Inhibition of human placental aromatase activity by hydroxylated polybrominated diphenyl ethers (OH-PBDEs).

Science.gov (United States)

Cantón, Rocío F; Scholten, Deborah E A; Marsh, Göran; de Jong, Paul C; van den Berg, Martin

2008-02-15

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in many different polymers, resins and substrates. Due to their widespread production and use, their high binding affinity to particles, and their lipophilic properties, several PBDE congeners can bioaccumulate in the environment. As a result, PBDEs and their hydroxylated metabolites (OH-PBDEs) have been detected in humans and various wildlife samples, such as birds, seals, and whales. Furthermore, certain OH-PBDEs and their methoxylated derivatives (MeO-PBDEs) are natural products in the marine environment. Recently, our laboratory focused on the possible effects on steroidogenesis of PBDEs and OH-PBDEs, e.g. in the human adrenocortical carcinoma (H295R) cell line indicating that some OH-PBDEs can significantly influence steroidogenic enzymes like CYP19 (aromatase) and CYP17. In the present study, human placental microsomes have been used to study the possible interaction of twenty two OH-PBDEs and MeO-PBDEs with aromatase, the enzyme that mediates the conversion of androgens into estrogens. All OH-PBDE derivates showed significant inhibition of placental aromatase activity with IC(50) values in the low micromolar range, while the MeO-PBDEs did not have any effect on this enzyme activity. Enzyme kinetics studies indicated that two OH-PBDEs, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE47) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), had a mixed-type inhibition of aromatase activity with apparent K(i)/K(i)' of 7.68/0,02 microM and 5.01/0.04 microM respectively. For comparison, some structurally related compounds, a dihydroxylated polybrominated biphenyl, which is a natural product (2,2'-dihyroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80)) and its non-bromo derivative were also included in the study. Again inhibition of aromatase activity could be measured, but their potency was significantly less than those observed for the OH-PBDEs. These results show that a

Inhibition of human placental aromatase activity by hydroxylated polybrominated diphenyl ethers (OH-PBDEs)

International Nuclear Information System (INIS)

Canton, Rocio F.; Scholten, Deborah E.A.; Marsh, Goeran; Jong, Paul C. de; Berg, Martin van den

2008-01-01

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in many different polymers, resins and substrates. Due to their widespread production and use, their high binding affinity to particles, and their lipophilic properties, several PBDE congeners can bioaccumulate in the environment. As a result, PBDEs and their hydroxylated metabolites (OH-PBDEs) have been detected in humans and various wildlife samples, such as birds, seals, and whales. Furthermore, certain OH-PBDEs and their methoxylated derivatives (MeO-PBDEs) are natural products in the marine environment. Recently, our laboratory focused on the possible effects on steroidogenesis of PBDEs and OH-PBDEs, e.g. in the human adrenocortical carcinoma (H295R) cell line indicating that some OH-PBDEs can significantly influence steroidogenic enzymes like CYP19 (aromatase) and CYP17. In the present study, human placental microsomes have been used to study the possible interaction of twenty two OH-PBDEs and MeO-PBDEs with aromatase, the enzyme that mediates the conversion of androgens into estrogens. All OH-PBDE derivates showed significant inhibition of placental aromatase activity with IC 50 values in the low micromolar range, while the MeO-PBDEs did not have any effect on this enzyme activity. Enzyme kinetics studies indicated that two OH-PBDEs, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE47) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), had a mixed-type inhibition of aromatase activity with apparent K i /K i ' of 7.68/0,02 μM and 5.01/0.04 μM respectively. For comparison, some structurally related compounds, a dihydroxylated polybrominated biphenyl, which is a natural product (2,2'-dihyroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80)) and its non-bromo derivative were also included in the study. Again inhibition of aromatase activity could be measured, but their potency was significantly less than those observed for the OH-PBDEs. These results show that a wide

Polybrominated diphenyl ether (PBDE) effects in rat neuronal cultures: 14C-PBDE accumulation, biological effect, and structure-activity relationships

Energy Technology Data Exchange (ETDEWEB)

Kodavanti, P.R.; Ward, T. [Neurotoxicology Div., NHEERL/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States); Burka, T. [National Insts. of Environmental Health Sciences, Research Triangle Park, NC (United States); Ludewig, G.; Robertson, L. [The Univ. of Iowa Coll. of Public Health, Iowa City, IA (United States); Birnbaum, L. [Experimental Toxicology Div., NHEERL/ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

2004-09-15

Polybrominated diphenyl ethers (PBDEs) are used as flame-retardants in many types of consumer products such as electrical equipment, plastics, and building materials. PBDEs are structurally similar to dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs). PBDEs are now ubiquitous; they can be found in air, water, fish, birds, marine mammals, and humans, and in many cases, they are increasing over time. In spite of their widespread occurrence in the environment, only limited information is available on the toxicology of PBDEs. Recent studies showed that PBDE exposure caused aberrations in spontaneous behavior and reduced learning and memory in mice these effects are similar to those seen after exposure to DDT or PCBs. However, the mode of action for this group of chemicals remains unclear. Previously, we demonstrated that PCBs, which are known to cause neurotoxic effects, affected intracellular signaling pathways including [{sup 3}H]arachidonic acid ([{sup 3}H]AA) release, calcium homeostasis, and translocation of protein kinase C (PKC). Regarding PBDEs, we have reported that PBDEs altered [{sup 3}H]AA release in neuronal cultures like PCBs. These signaling pathways have been associated with learning and memory, and the development of the nervous system. The objectives of the present study were to test: (a) whether biologically relevant PBDE congeners affected PKC translocation in neuronal cultures in a similar way to those of other organohalogens; (b) compare the potency and efficacy of PBDE congeners with their 14C-accumulation; and (c) understand the structure-activity relationships among PBDE congeners.

Hydroxylated PBDEs induce developmental arrest in zebrafish

Energy Technology Data Exchange (ETDEWEB)

Usenko, Crystal Y., E-mail: Crystal_usenko@baylor.edu; Hopkins, David C.; Trumble, Stephen J., E-mail: Stephen_trumble@baylor.edu; Bruce, Erica D., E-mail: Erica_bruce@baylor.edu

2012-07-01

The ubiquitous spread of polybrominated diphenyl ethers (PBDEs) has led to concerns regarding the metabolites of these congeners, in particular hydroxylated PBDEs. There are limited studies regarding the biological interactions of these chemicals, yet there is some concern they may be more toxic than their parent compounds. In this study three hydroxylated PBDEs were assessed for toxicity in embryonic zebrafish: 3-OH-BDE 47, 5-OH-BDE 47, and 6-OH-BDE 47. All three congeners induced developmental arrest in a concentration-dependent manner; however, 6-OH-BDE 47 induced adverse effects at lower concentrations than the other congeners. Furthermore, all three induced cell death; however apoptosis was not observed. In short-term exposures (24–28 hours post fertilization), all hydroxylated PBDEs generated oxidative stress in the region corresponding to the cell death at 5 and 10 ppm. To further investigate the short-term effects that may be responsible for the developmental arrest observed in this study, gene regulation was assessed for embryos exposed to 0.625 ppm 6-OH-BDE 47 from 24 to 28 hpf. Genes involved in stress response, thyroid hormone regulation, and neurodevelopment were significantly upregulated compared to controls; however, genes related to oxidative stress were either unaffected or downregulated. This study suggests that hydroxylated PBDEs disrupt development, and may induce oxidative stress and potentially disrupt the cholinergic system and thyroid hormone homeostasis. -- Highlights: ► OH-PBDEs induce developmental arrest in a concentration-dependent manner. ► Hydroxyl group location influences biological interaction. ► OH-PBDEs induce oxidative stress. ► Thyroid hormone gene regulation was disrupted following exposure. ► To our knowledge, this is the first whole organism study of OH-PBDE toxicity.

Long term trends in PBDE concentrations in gannet (Morus bassanus) eggs from two UK colonies

International Nuclear Information System (INIS)

Crosse, John D.; Shore, Richard F.; Jones, Kevin C.; Pereira, M. Glória

2012-01-01

We used the eggs of an avian sentinel, the Northern gannet (Morus bassanus), to determine long-term (1977–2007) trends in PBDE contamination in Western Atlantic (Ailsa Craig colony) and North Sea (Bass Rock colony) waters around the UK. BDEs 47, 49, 99, 100, 153, 154 were the most abundant and were found in all eggs. Individual congener and ΣPBDE concentrations in eggs from both colonies increased mainly from the late 1980s, peaked in 1994, and then rapidly declined so that concentrations in 2002 were similar to or lower than those in the 1970s and 1980s. The PBDE congener profile and temporal variation in PBDE concentrations suggests that the Penta-BDE technical formula was the main source of PBDE contamination. However, contributions of heavier BDE congeners to ΣPBDE concentrations have increased over time, suggesting other sources are becoming more important. PBDEs had no measurable effect on egg volume or eggshell index. - Highlights: ► Detailed long-term (1977–2007) PBDE trends are presented in gannet eggs from the UK. ► Temporal trends mirror consumption of PeBDE technical products. ► In recent years the PBDE profile heavier BDEs became increasingly more important. ► BDE35 concentrations decreased linearly throughout the monitoring period. ► ΣPBDE levels in gannet eggs are below levels linked to impaired reproductive output. - PBDE levels in gannet eggs from two UK colonies mirrored patterns of PBDE consumption, but sources other than PeBDE became more prevalent in recent years.

Differences in neonatal neurotoxicity of brominated flame retardants, PBDE 99 and TBBPA, in mice

International Nuclear Information System (INIS)

Viberg, Henrik; Eriksson, Per

2011-01-01

Highlights: → Neonatal exposure to PBDE 99, but not TBBPA, causes changes in the neonatal brain. → CaMKII increases in neonatal hippocampus after PBDE 99 exposure. → CaMKII, GAP-43 and synaptophysin increase in neonatal cortex after PBDE 99 exposure. → CaMKII increase in hippocampus has earlier been seen to proceed behavioral changes. → Neonatal exposure to PBDE 99, but not TBBPA, is known to cause behavioral deficits. -- Abstract: Flame retardants such as polybrominated diphenyl ethers (PBDE) and tetrabromobisphenol A are used as flame retardants and detected in the environmental, wildlife species and human tissues. Exposure to PBDEs during the neonatal development of the brain has been shown to affect behavior and learning and memory in adult mice, while neonatal exposure to TBBPA (another brominated flame retardant) did not affect behavioral variables in the adult. In this study, we hypothesized that the effects of these compounds could be reflected by changes in biochemical substrates and cholinergic receptors and have examined the levels of four proteins involved in maturation of the brain, neuronal growth and synaptogenesis and the densities of both muscarinic and nicotinic cholinergic receptors. We measured the levels of radioactivity in the brain after administration of 14 C-labelled TBBPA at different time points and saw that levels of TBBA peaked earlier and decreased faster than the earlier reported levels of PBDE 99. The protein analysis in the neonatal brain showed changes in the levels of calcium/calmodulin-dependent protein kinase II (CaMKII), growth associated protein-43 (GAP-43) and synaptophysin following neonatal exposure to PBDE 99 (21 μmol/kg body weight), but not following exposure TBBPA. Furthermore, neonatal exposure to PBDE 99 and TBBPA caused a decrease in binding sites of the nicotinic ligand cytisine in frontal cortex. These results confirm earlier reported data that PBDE 99 can act as a developmental neurotoxicant, possibly

Determination and prediction of octanol-air partition coefficients of hydroxylated and methoxylated polybrominated diphenyl ethers.

Science.gov (United States)

Zhao, Hongxia; Xie, Qing; Tan, Feng; Chen, Jingwen; Quan, Xie; Qu, Baocheng; Zhang, Xin; Li, Xiaona

2010-07-01

The octanol-air partition coefficient (K(OA)) of 19 hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and 10 methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were measured as a function of temperature using a gas chromatographic retention time technique. At room temperature (298.15K), log K(OA) ranged from 8.30 for monobrominated OH/MeO-PBDEs to 13.29 for hexabrominated OH/MeO-PBDEs. The internal energies of phase change from octanol to air (Delta(OA)U) for 29 OH/MeO-PBDE congeners ranged from 72 to 126 kJ mol(-1). Using partial least-squares (PLS) analysis, a statistically quantitative structure-property relationship (QSPR) model for logK(OA) of OH/MeO-PBDE congeners was developed based on the 16 fundamental quantum chemical descriptors computed by PM3 Hamiltonian, for which the Q(cum)(2) was about 0.937. The molecular weight (Mw) and energy of the lowest unoccupied molecular orbital (E(LUMO)) were found to be main factors governing the log K(OA). 2010 Elsevier Ltd. All rights reserved.

Brominated diphenyl ether levels. A comparison of tributary sediments versus biosolid material

Energy Technology Data Exchange (ETDEWEB)

Kolic, T.M.; MacPherson, K.A.; Reiner, E.J. [Ontario Ministry of the Environment, Laboratory Services Branch, Toronto, ON (Canada); Ho, T.; Kleywegt, S. [Ontario Ministry of the Environment, Standards Development Branch, Toronto, ON (Canada); Dove, A.; Marvin, C. [Environment Canada, Burlington, ON (Canada)

2004-09-15

PBDEs are persistent in the environment, have low water solubility and are known to have a tendency to bioaccumulate in wildlife and humans. There are 209 possible PBDE congeners. There has been concern over the bioaccumulation of these compounds since they have been found in mother's milk. Some of the brominated diphenyl ethers are known to metabolize into hydroxylated compounds and these metabolites are known to compete with and reduce thyroxine (T4) from binding to the thyroxine binding protein, transthyretin. This disrupts the thyroid hormone system interaction that has recently been notable amongst women in the form of hypothyroidism that can affect the fetus development in the form of neurodevelopmental deficits. There have been reports of estrogenic activities regarding PBDEs and their hydroxylated counterparts. Information such as this is indicative that PBDEs are endocrine disruptors. Due to their lipophilic nature, PBDEs have a high binding affinity to particulates and accumulate in sediments. Various reports on sediments and sludge type matrices have been reported in Austria, Switzerland, Netherlands and Canada. The following paper is a presentation of levels of PBDEs found in Tributary sediments and their comparison of levels to nearby biosolid sampling locations along Lake Ontario.

PBDE levels in human milk: the situation in Germany and potential influencing factors - a controlled study

Energy Technology Data Exchange (ETDEWEB)

Vieth, B.; Mielke, H.; Ostermann, B.; Ruediger, T. [Federal Inst. for Risk Assessment, Berlin (Germany); Herrmann, T.; Paepke, O. [ERGO Forschungsgesellschaft mbH, Hamburg (Germany)

2004-09-15

An exponential increase of PBDE levels in breast milk from Sweden between 1972 and 1997 has been reported, which is in contrast to the continuous decline of other chlorinated POPs in breast milk. Also in blood samples from Germany, an increasing trend has been observed during the period from 1985 to 1999. The knowledge about human exposure pathways, which contribute to the PBDE body burden, is very limited. Consumption of food of animal origin, inhalation or ingestion of dust and further factors possibly influencing the PBDE levels in human matrices, like age, breast-feeding or smoking are under discussion. Only a few data on PBDE levels in breast milk from Germany have been published. To fill the data gaps, a controlled study was started in 2001 to characterise the PBDE levels in human milk from Germany with special efforts to identify and quantify deca-BDE-209. Furthermore, it was intended to verify potential factors possibly influencing PBDE levels. Two main hypotheses were proposed: (1) Are PBDE levels in breast milk from mothers consuming traditional food (omnivores) higher than those found in breast milk from mothers consuming vegetarian or vegan food? and (2) Are the PBDE levels found in human milk after a three-months period of breast-feeding lower than those detected at the beginning or does breast feeding result in a lower body burden, respectively? This paper summarises preliminary results. Further analytical data and results of data evaluation will be presented at the conference.

Spatial trends of polybrominated diphenyl ether (PBDE) congeners

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Spatial trends of polybrominated diphenyl ether (PBDE) congeners were analyzed in young of the year bluefish collected along the U.S. Atlantic coastline from...

Revisión global de los contaminantes emergentes PBDE y el caso particular de México

OpenAIRE

Rocha-Gutiérrez, Beatriz Adriana; Peralta-Pérez, María del Rosario; Zavala-Díaz de la Serna, Francisco Javier

2015-01-01

Los éteres de bifenilos polibromados (PBDE, por sus siglas en inglés) son un grupo específico de contaminantes emergentes que se caracterizan por ser lipofílicos, hidrofóbicos, bioacumulables y resistentes a la biodegradación. La familia de PBDE consiste de 209 isómeros o congéneres y su estructura química, persistencia y distribución en el ambiente siguen patrones muy similares a los polibromobifenilos (PBB) y a los policlorobifenilos (PCB). El uso principal de los PBDE es como retardantes d...

Global occurrence of polybrominated diphenyl ethers and their hydroxylated and methoxylated structural analogues in an important animal feed (fishmeal).

Science.gov (United States)

Li, Xiaomin; Dong, Shujun; Zhang, Wei; Fan, Xia; Li, Yang; Wang, Ruiguo; Su, Xiaoou

2018-03-01

Polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH) and methoxylated (MeO) structural analogues have been found widely distributed in aquatic ecosystems, and may exhibit potential adverse effects to humans due to their bioaccumulative behavior through food chain. Fishmeal is an important animal feed applied around the world and is generally of marine origin. However, the levels and sources of PBDEs in fishmeal have not been thoroughly evaluated and their structural analogues have not been reported to date. The present study collected ninety-two fishmeal samples from world main fishmeal producing area to determine 27 PBDEs, 10 MeO-PBDEs and 11 OH-PBDEs. The concentrations of Σ 27 PBDEs, Σ 10 MeO-PBDEs and Σ 11 OH-PBDEs were in the ranges of 0.1-1498 (mean: 75.8), 1.14-881 (37.4) and 1.00-47.5 (8.17) ng/g lipid, respectively. PBDEs were found primarily correlated with the historically commercial production, meaning higher production of certain commercial product in a country, higher corresponding PBDE congeners in local fishmeal. A market shift from penta- and octa-formulations toward deca-formulation was observed. BDE209 was identified as a major congener in fishmeal. Both the MeO-PBDEs and the OH-PBDEs were influenced by fishmeal producing areas (p 1 in the northern hemisphere and <1 in the southern hemisphere in the present study, which was consistent with the results obtained from previous published papers. Both MeO-PBDEs and OH-PBDEs were in accordance with the specialties of naturally produced halogenated compounds. Copyright © 2017. Published by Elsevier Ltd.

Highest PBDE levels (max 63 ppm) yet found in biota measured in seabird eggs from San Francisco Bay

Energy Technology Data Exchange (ETDEWEB)

She, J.; Holden, A.; Tanner, M.; Sharp, M.; Hooper, K. [Department of Toxic Substances Control, Berkeley, CA (United States). Hazardous Materials Lab.; Adelsbach, T. [Environmental Contaminants Division, Sacramento Fish and Wildlife Office, US Fish and Wildlife Service, Sacramento, CA (United States)

2004-09-15

High levels of polybrominated diphenylethers (PBDEs) have been found in humans and wildlife from the San Francisco Bay Area, with levels in women among the highest in the world, and levels in piscivorous seabird eggs at the ppm level. Seabirds are useful for monitoring and assessing ecosystem health at various times and places because they occupy a high trophic level in the marine food web, are long-lived, and are generally localized near their breeding and non-breeding sites. In collaboration with the US Fish and Wildlife Services (USFWS), we are carrying out a three-year investigation of dioxin, PCB and PBDE levels in eggs from fish-eating seabirds. Year 1 (2002) PBDE measurements from 73 bird eggs were reported at Dioxin2003. Year 2 (2003) PBDE measurements from 45 samples are presented in this report. The highest PBDE level measured in eggs was 63 ppm, lipid, which is the highest PBDE level, yet reported in biota.

Thyroid hormone levels and hepatic enzyme activity in lactating dams after gestational exposure to low dose PBDE 47

Energy Technology Data Exchange (ETDEWEB)

Kuriyama, S.N.; Grande, S.W.; Akkoc, Z.; Souza, C.A.M. de; Chahoud, I. [Charite Univ. Medical School Berlin (Germany). Inst. of Clinical Pharmacology and Toxicology, Dept. Toxicology, Campus Benjamin Franklin; Fidalgo-Neto, A.A. [Oswaldo Cruz Foundation, Rio de Janeiro (Brazil). Lab. of Environmental Toxicology

2004-09-15

Polybrominated diphenyl ethers (PBDEs), a class of widely used flame retardants, are found extensively in the environment (shown by several studies on sentinel animal species), as well as in humans. In rodents, technical commercial PBDE mixtures and individual congeners have shown to interfere with thyroid hormone homeostasis, produce a mix-type induction of hepatic microsomal enzymes, disrupt spontaneous behaviour, impair learning and memory and alter the cholinergic transmitter system. In rat and mice, some technical PBDE commercial mixtures such as DE-71 and Bromkal 70 and the congener PBDE 47 have shown to decrease circulating thyroid hormone levels. PBDEs are also able to induce both hepatic phase I and phase II detoxification enzymes, demonstrated by several investigations in laboratory animals. For example, induction of ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-Odespenthylase (PROD) and uridinediphospho-glucuronosyltransferase (UDPGT) has been shown in rodents and cell lines after exposure to technical mixtures or individual congeners. However, these studies deal with doses much higher than that found in human tissues, highlighting the importance of assessing the adverse effects of doses close to human exposure levels. PBDE 47 is the most predominant congener found in environmental and human samples (including human milk) and, therefore, hazard identification is extremely important for human risk assessment. We administered a single dose to gravid dams on gestation day 6 of either 140 {mu}g/kg BW or 700 {mu}g/kg BW of the congener, 2,2'4,4'-tetrabromo diphenyl ether (PBDE 47). These doses are pertinent to human exposure levels because a study by She et al. found a mean level of 33.3 {mu}g PBDE 47 /kg fat in human breast adipose tissue with a range from 7.01 to 196 {mu}g PBDE 47 /kg fat. In this study, thyroid hormone levels and hepatic enzyme activity were evaluated in lactating dams after in utero administration of low dose PBDE 47.

Hepatic in vitro toxicity assessment of PBDE congeners BDE47, BDE153 and BDE154 in Atlantic salmon (Salmo salar L.)

Energy Technology Data Exchange (ETDEWEB)

Softeland, Liv, E-mail: lso@nifes.no [National Institute of Nutrition and Seafood Research, PO Box 2029 Nordnes, N-5817 Bergen (Norway); Petersen, Kjell [Computational Biology Unit, Bergen Centre for Computational Science, Uni Research AS, Thormohlensgt 55, N5008 Bergen (Norway); Stavrum, Anne-Kristin [Dept of Clinical Medicine, University of Bergen (Norway); Wu, Terence [Yale University W.M. Keck Biotechnology Resource, 300 George St., Room G001, New Haven, CT 06511 (United States); Olsvik, Pal A. [National Institute of Nutrition and Seafood Research, PO Box 2029 Nordnes, N-5817 Bergen (Norway)

2011-10-15

The brominated flame retardant congeners BDE47, BDE153 and BDE154 are among the congeners accumulating to the highest degree in fish. In order to gain knowledge about the toxicological effects of PBDEs in fish, microarray-based transcriptomic and 2D-DIGE/MALDI-TOF/TOF proteomic approaches were used to screen for effects in primary Atlantic salmon hepatocytes exposed to these congeners alone or in combination (PBDE-MIX). A small set of stress related transcripts and proteins were differentially expressed in the PBDE exposed hepatocytes. The PBDE-MIX, and BDE153 to a lesser degree, seems to have induced metabolic disturbances by affecting several pathways related to glucose homeostasis. Further, effects on cell cycle control and proliferation signal pathways in PBDE-MIX-exposed hepatocytes clearly suggest that the PBDE exposure affected cell proliferation processes. CYP1A was 7.41- and 7.37-fold up-regulated in hepatocytes exposed to BDE47 and PBDE-MIX, respectively, and was the only biotransformation pathway affected by the PBDE exposure. The factorial design and PLS regression analyses of the effect of the PBDE-MIX indicated that BDE47 contributed the most to the observed CYP1A response, suggesting that this congener should be incorporated in the toxic equivalent (TEQ) concept in future risk assessment of dioxin-like chemicals. Additionally, a significant up-regulation of the ER-responsive genes VTG and ZP3 was observed in cells exposed to BDE47 and PBDE-MIX. Further analyses suggested that BDE47 and BDE154 have an estrogenic effect in male fish. The data also suggested an antagonistic interaction between BDE153 and BDE154. In conclusion, this study shows that PBDEs can affect several biological systems in Atlantic salmon cells, and demonstrates the need for more studies on the simultaneous exposure to chemical mixtures to identify combined effects of chemicals.

Toxicity and physiological effects of brominated flame retardant PBDE-47 on two life stages of grass shrimp, Palaemonetes pugio.

Science.gov (United States)

Key, Peter B; Chung, Katy W; Hoguet, Jennifer; Shaddrix, Brian; Fulton, Michael H

2008-07-25

This study examined the effects of a polybrominated diphenyl ether (PBDE) compound, PBDE-47, on adult and larval stages of the estuarine grass shrimp (Palaemonetes pugio). The 96-h LC50 test resulted in an estimate of 23.60 microg/L (95% confidence interval=14.51-38.37 microg/L) for larval shrimp. Adult shrimp had a higher 96-h LC50 of 78.07 microg/L (95% CI=65.1-93.63 microg/L). Four physiological biomarkers glutathione (GSH), lipid peroxidation (LPx), cholesterol (CHL) and acetylcholinesterase (AChE) were then assessed to study the sublethal effects of PBDE-47 exposure. GSH, LPx and AChE levels in both adults and larvae were not affected by PBDE-47 at concentrations up to 50 microg/L for 96 h. CHL levels were elevated in adults and larvae at the lowest exposure concentrations tested, but significant differences were found only in adult exposures. Effects associated with PBDE-47 aqueous exposures were observed at levels well above those reported in the environment.

Levels and distribution of polybrominated diphenyl ethers (PBDEs) in the freshwater environment surrounding a PBDE manufacturing plant in China

International Nuclear Information System (INIS)

Xu Jie; Gao Zishen; Xian Qiming; Yu Hongxia; Feng Jianfang

2009-01-01

Polybrominated diphenyl ethers (PBDEs) were determined in muscle, liver and eggs of freshwater fishes and surface sediments from the Nongkang River in Jinhu, Jiangsu Province, China. The present study is the first to report PBDE concentrations in the freshwater environment surrounding a PBDE manufacturing plant in China. The concentrations of 13 PBDE congeners in muscle, liver and eggs of freshwater fishes ranged from < LOD to 130, < LOD to 252 and < LOD to 33.3 ng/g lipid wt, respectively, while the concentrations of 13 PBDE congeners in surface sediments from sewage outfall, upstream and downstream of the river were 52, 9.2, 7.1 ng/g organic carbon wt, respectively. Contamination by PBDEs in this area was not serious when compared with other regions of the world. A relatively high proportion of BDE-183 was found, consistent with the octa-BDE technical mixtures from the manufacturing plant by the side of the river. - The first study to report concentrations of PBDEs in the freshwater environment surrounding a PBDE manufacturing plant in China.

Serum PBDE levels in exposed rats in relation to effects on thyroxine homeostasis

Energy Technology Data Exchange (ETDEWEB)

Darnerud, P.O.; Aune, M.; Larsson, L.; Hallgren, S. [National Food Administration, Uppsala (Sweden)

2004-09-15

Brominated flame retardants (BFRs) is a group of environmental chemicals for which lately both interest and knowledge have increased considerably. Among the BFRs, the polybrominated diphenyl ethers (PBDEs) have attained special interest. Much data on environmental and human levels have been presented and several toxicological reviews are now published. Among interesting results is the difference in human PBDE levels that seem to exist between U.S.A. and Europe, results that suggest differences in exposure but without being able to pin-point the exact sources. In experimental studies PBDEs alter serum thyroxin levels, an effect seen both in rats and in mice. The mechanism(s) are still not completely clarified, but are thought to include alterations in serum transport, induced enzymatic degradation and possibly also direct effects on the thyroid gland. As perinatal alterations in thyroid homeostasis could affect brain development, early effects on thyroid hormones may be of special concern. Indeed, PBDEs have been shown to affect behaviour and learning in mice, when given neonatally. The aim of the present study was to relate the serum levels of PBDEs in rats to effects of these compounds on thyroxine homeostasis in these animals. Specifically, the relation between serum PBDE levels and effects on serum thyroxine levels was investigated, after two weeks of daily oral exposure. The result may have consequences for the future risk assessment activities on PBDE and specifically in finding the critical serum PBDE concentration at which the effect on thyroid hormone levels begin to occur.

Associations between serum levels of polybrominated diphenyl ether (PBDE) flame retardants and environmental and behavioral factors in pregnant women.

Science.gov (United States)

Buttke, Danielle E; Wolkin, Amy; Stapleton, Heather M; Miranda, Marie Lynn

2013-03-01

Polybrominated diphenyl ethers (PBDE) are flame retardants that were previously used in upholstery, fabrics, and household appliances. PBDEs have been linked to adverse health outcomes, including neurotoxicity, thyroid hormone dysregulation, endocrine disruption, and poor semen quality. Because PBDEs pass into placental circulation, maternal exposures can approximate fetal exposures. Our objectives were to determine whether diet and specific human behaviors were significantly associated with PBDE exposures in a cohort of pregnant women. Women between the 34th and 38th week of pregnancy were given a questionnaire about behavioral, environmental, and dietary factors and asked to provide blood samples. Serum PBDE levels were measured using GS-MS and lipid adjusted. An adjusted ordinary least squares regression model was run to identify potential associations between behaviors and serum PBDE levels. Serum concentrations of BDEs 47, 99, 100, and 153 were found above the limit of detection in at least 50% of study participants and used in our models. Associations with serum PBDEs were observed with self-reported hand-to-mouth behaviors, including biting nails and licking fingers. Serum BDE levels of 47, 99, 153, and total PBDEs were also significantly higher in those individuals owning a large-screen TV compared with those who did not. Serum PBDE levels were comparable to levels reported in the general population. Hand-to-mouth behaviors may influence serum PBDE concentrations in adults. Household electronics such as large-screen TVs appear to serve as a significant source of PBDEs in pregnant women. Together, hand-to-mouth behaviors and TV ownership may serve as a route of exposure to PBDEs in adults.

Effects of developmental exposure to a Commercial PBDE mixture (DE-71) on protein networks in the rat Cerebellum and Hippocampus

Science.gov (United States)

Title (20 words): Effects of developmental exposure to a Commercial PBDE mixture (DE-71) on protein networks in the rat Cerebellum and Hippocampus. Introduction (120 words): Polybrominated diphenyl ethers (PBDE5) possess neurotoxic effects similar to those of PCBs. The cellular a...

Widespread polybrominated diphenyl ether (PBDE) contamination of urban soils in Melbourne, Australia.

Science.gov (United States)

McGrath, Thomas J; Morrison, Paul D; Sandiford, Christopher J; Ball, Andrew S; Clarke, Bradley O

2016-12-01

Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in a variety of materials and products. PBDEs have been shown to accumulate in the environment and human populations while exhibiting a range of toxic effects. In this study, surface soil samples from 30 sites in the city of Melbourne, Australia, were analysed for PBDEs. Eight congeners of environmental concern (BDE-28, -47, -99, -100, -153, -154 -183 and -209) were assessed using selective pressurized liquid extraction (S-PLE) and gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS). PBDEs were detected in 29/30 samples with Σ 8 PBDE soil concentrations ranging nd-13,200 ng/g dw and Σ 7 PBDEs (excluding BDE-209) levels of nd-70.5 ng/g dw. Soils from waste disposal sites (n = 6) contained the highest median Σ 7 PBDE and Σ 8 PBDE concentrations, followed by manufacturing sites (n = 18) and then non-source sites (n = 6). Electronics recycling facilities contained the greatest levels of Σ 8 PBDEs by a significant margin (p production, with the most significant congener correlation existing between BDE-47 and BDE-99 (p < 0.001, r = 0.943). This first assessment of PBDEs in Melbourne soils indicates widespread contamination of the urban environment, including locations where direct sources to soil are not clear. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of wild trout for PBDE assessment in freshwater environments: Review and summary of critical factors

Directory of Open Access Journals (Sweden)

Juan M. Ríos

2015-11-01

Full Text Available Certain wild animals represent sentinels to address issues related to environmental pollution, since they can provide integrative data on both pollutant exposure and biological effects. Despite their technological benefits, PBDEs are considered a threat to environmental health due to their persistence, toxicity, and capacity to be accumulated. These pollutants have been found geographically widespread in fish, particularly in predator species such as trout. The aim of this work is to critically review the applicability and usefulness of wild trout for assessing PBDEs in freshwater environments. Reviewed reports include data from highly industrialized areas as well as areas from remote regions with relatively low human activity, including European and North American great lakes and freshwater environments in Europe, Greenland, subarctic areas and Patagonia, respectively. A summary of relevant factors were grouped into organism-specific factors (food habits, age, size, lipid content, sex and reproduction, tissue type, mechanism of contaminant uptake and metabolism, and PBDE levels in the surrounding environment (sediment. Five wild trout species [rainbow trout (Oncorhynchus mykiss, brown trout (Salmo trutta, lake trout (Salvelinus namaycush, arctic char (Salvelinus alpinus, and brook trout (Salvelinus fontinalis], collected worldwide within the 1994 to present time frame, were considered. Multivariate techniques (principal component analysis-PCA and mapping approach, showed clear differences in geographic distribution patterns of PBDE levels in trout depending on the region studied: wild trout from European and North American great lakes have the highest PBDE loads. This pattern could be due to high industrial activity at these locations. A correlational approach used to explore intraspecific relationships between PBDE levels and morphometry, showed positive relationships only for brown trout. Further, brown trout showed the highest trout

Bioaccumulation and biomagnification of classical flame retardants, related halogenated natural compounds and alternative flame retardants in three delphinids from Southern European waters

International Nuclear Information System (INIS)

Barón, E.; Giménez, J.; Verborgh, P.; Gauffier, P.; De Stephanis, R.; Eljarrat, E.; 2O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona (Spain))" data-affiliation=" (Institute of Environmental Assessment and Water Research Studies (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona (Spain))" >Barceló, D.

2015-01-01

Occurrence and behaviour of classical (PBDEs) and alternative (HNs, HBB, PBEB, DBDPE and HBCD) flame retardants, together with naturally produced MeO-PBDEs, were studied in short-beaked common dolphin (Delphinus delphis), bottlenose dolphin (Tursiops truncatus) and long-finned pilot whale (Globicephala melas) in two sampling locations from Southern European waters. PBDEs, Dec 602, Dec 603, DP, α-HBCD and two MeO-PBDEs were detected in all three species. ∑PBDEs were between 17 and 2680 ng/g lw; ∑HNs were between 1.1 and 59 ng/g lw; α-HBCD levels ranged between 3.2 and 641 ng/g lw; ∑MeO-PBDEs were between 34 and 1966 ng/g lw. Bottlenose dolphins were the most contaminated species and some individuals could present health risk for endocrine disruption since levels found were above the reported threshold (1500 ng/g lw). Stable isotope analysis was used to evaluate the biomagnification capacity of these compounds. PBDEs, MeO-PBDEs and Dec 602 showed a significant positive correlation with trophic position. - Highlights: • Several FRs were detected in three dolphin species from Southern European waters. • Concentrations of classical FRs were higher than concentrations of alternative FRs. • MeO-PBDE concentrations were generally similar to PBDE concentrations. • Evidence of biomagnification capacity of some FRs was observed. • Some individuals were above the threshold level associated to endocrine disruption. - Bioaccumulation and biomagnification of halogenated compounds in dolphins

Exposure to brominated flame retardant PBDE-99 affects cytoskeletal protein expression in the neonatal mouse cerebral cortex

DEFF Research Database (Denmark)

Alm, Henrik; Kultima, Kim; Scholz, Birger

2008-01-01

, and the cytotoxic and apoptotic effects of PBDE-99 in primary cultures of fetal rat cortical cells. We used two-dimensional difference gel electrophoresis (2D-DIGE) to analyze protein samples isolated from the cortex of NMRI mice 24h after exposure to a single oral dose of 12 mg/kg PBDE-99 on post-natal day 10....... Protein resolution was enhanced by sample pre-fractionation. In the cell model, we determined cell viability using the trypan blue exclusion assay, and apoptosis using immunocytochemical detection of cleaved caspase-3. We determined the identity of 111 differentially expressed proteins, 32 (29%) of which...... are known to be cytoskeleton-related. Similar to previous findings in the striatum, we found elevated levels of the neuron growth-associated protein Gap43 in the cortex. In cultured cortical cells, a high concentration of PBDE-99 (30 microM) induced cell death without any apparent increase in caspase-3...

Bioaccumulation factors for radionuclides in freshwater biota

International Nuclear Information System (INIS)

Vanderploeg, H.A.; Parzyck, D.C.; Wilcox, W.H.; Kercher, J.R.; Kaye, S.V.

1975-11-01

This report analyzes over 200 carefully selected papers to provide concise data sets and methodology for estimation of bioaccumulation factors for tritium and isotopes of strontium, cesium, iodine, manganese, and cobalt in major biotic components of freshwater environments. Bioaccumulation factors of different tissues are distinguished where significant differences occur. Since conditions in the laboratory are often unnatural in terms of chemical and ecological relationships, this review was restricted as far as possible to bioaccumulation factors determined for natural systems. Because bioaccumulation factors were not available for some shorter-lived radionuclides, a methodology for converting bioaccumulation factors of stable isotopes to those of shorter-lived radionuclides was derived and utilized. The bioaccumulation factor for a radionuclide in a given organism or tissue may exhibit wide variations among bodies of water that are related to differences in ambient concentrations of stable-element and carrier-element analogues. To account for these variations, simple models are presented that relate bioaccumulation factors to stable-element and carrier-element concentrations in water. The effects of physicochemical form and other factors in causing deviations from these models are discussed. Bioaccumulation factor data are examined in the context of these models, and bioaccumulation factor relations for the selected radionuclides are presented

Neonatal exposure to polybrominated diphenyl ether (PBDE 153) disrupts spontaneous behaviour, impairs learning and memory, and decreases hippocampal cholinergic receptors in adult mice

International Nuclear Information System (INIS)

Viberg, Henrik; Fredriksson, Anders; Eriksson, Per

2003-01-01

Neonatal exposure to polybrominated diphenyl ether (PBDE 153) disrupts spontaneous behaviour, impairs learning and memory, and decreases hippocampal cholinergic receptors in adult mice. Flame retardants are used to suppress or inhibit combustion processes in an effort to reduce the risk of fire. One class of flame retardants, polybrominated diphenyl ethers (PBDEs), are present and increasing in the environment and in human milk. The present study shows that neonatal exposure to 2,2',4,4',5,5'-hexaBDE (PBDE 153), a PBDE persistent both in environment and in human milk, can induce developmental neurotoxic effects, such as changes in spontaneous behaviour (hyperactivity), impairments in learning and memory, and reduced amounts of nicotinic receptors, effects that get worse with age. Neonatal NMRI male mice were orally exposed on day 10 to 0.45, 0.9, or 9.0 mg of PBDE 153/kg of body weight. Spontaneous behaviour (locomotion, rearing, and total activity) was observed in 2-, 4-, and 6-month-old mice, Morris water maze at an age of 6 months. The behaviour tests showed that the effects were dose-response and time-response related. Animals showing defects in learning and memory also showed significantly reduced amounts of nicotinic receptors in hippocampus, using α-bungarotoxin binding assay. The observed developmental neurotoxic effects seen for PBDE 153 are similar to those seen for PBDE 99 and for certain PCBs. Furthermore, PBDEs appear to as potent as the PCBs

Do temporal and geographical patterns of HBCD and PBDE flame retardants in U.S. fish reflect evolving industrial usage?

Science.gov (United States)

Chen, Da; La Guardia, Mark J; Luellen, Drew R; Harvey, Ellen; Mainor, T Matteson; Hale, Robert C

2011-10-01

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) are common flame retardants in polymers and textiles. Recognition of the persistent, bioaccumulative, and toxic properties of PBDEs has prompted reductions in their use. In contrast, HBCD has received less scrutiny. The U.S has historically been a dominant BFR consumer. However, the few publications on HBCD in wildlife here suggest modest levels compared to Asian and European studies. In contrast, the HBCD concentrations we detected in U.S. fish are among the highest reported in the world. The temporal trends observed suggest that HBCD use may have risen, and that of Penta-BDE declined, following the 2004 termination of its U.S. manufacture. For example, Hyco River carp collected in 1999-2002 exhibited a mean ∑HBCD (sum of α-, β- and γ-HBCD) concentration of only 13 ng/g (lipid weight basis), but was 4640 ng/g in fish collected in 2006-2007. In contrast, the mean ∑PBDE level in these same fish decreased from 40,700 ng/g in 1999-2002 to 9140 ng/g in 2006-2007. Concentrations of HBCD and PBDEs in several Hyco River fish species exceeded those from rivers less influenced by manufacturing outfalls. Results support the contention that textile-related production, relative to its BFR market share, may release disproportionately large amounts of HBCD to the environment.

Effects of Feeding Strategy, Sediment Characteristics, and Chemical Properties on Polychlorinated Biphenyl and Polybrominated Diphenyl Ether Bioaccumulation from Marine Sediments in Two Invertebrates.

Science.gov (United States)

Frouin, H; Jackman, P; Dangerfield, N D; Ross, P S

2017-08-01

Shellfish and sediment invertebrates have been widely used to assess pollution trends over space and time in coastal environments around the world. However, few studies have compared the bioaccumulation potential of different test species over a range of sediment-contaminant concentrations and profiles. The bioavailability of sediment-related contaminants was evaluated using sediments collected from sites (n = 12) throughout the Salish Sea, British Columbia, Canada. Two benthic marine invertebrates-the Baltic clam Macoma balthica and the polychaete worm Neanthes arenaceodentata-were exposed for 28 days in a controlled environment to these field-collected coastal sediments. The congener-specific uptake of legacy polychlorinated biphenyls (PCBs) and emergent polybrominated diphenyl ethers (PBDEs) was determined using high-resolution gas chromatography/mass spectrometry in sediments and in invertebrates after the experimental exposure. The polychaete Neanthes accumulated lower concentrations of PCBs but higher concentrations of PBDEs. The present study indicates that differences in bioaccumulation between these two invertebrates shape the accumulation of PCB and PBDE congeners, reflect differences in feeding strategies, and reveal the physicochemical properties of the contaminants and sediment properties. Because biota-sediment accumulation factor values are often calculated for environmental monitoring or site-specific impact assessments, our results provide insight into potentially confounding factors and the need for caution when selecting indicator species for coastal marine pollution.

Effect of polybrominated diphenyl ether (PBDE) treatment on the composition and function of the bacterial community in the sponge Haliclona cymaeformis.

KAUST Repository

Tian, Ren-Mao

2014-01-01

Marine sponges play important roles in benthic environments and are sensitive to environmental stresses. Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants since the 1970s and are cytotoxic and genotoxic to organisms. In the present study, we studied the short-period effect of PBDE-47 (2,2\\',4,4\\'-tetrabromodiphenyl ether) treatment on the community structure and functional gene composition of the bacterial community inhabiting the marine sponge Haliclona cymaeformis. Our results showed that the bacterial community shifted from an autotrophic bacteria-dominated community to a heterotrophic bacteria-dominated community in response to PBDE-47 in a time- and concentration-dependent manner. A potentially symbiotic sulfur-oxidizing bacterium (SOB) was dominant (>80% in abundance) in the untreated sponge. However, exposure to a high concentration (1 μg/L) of PBDE-47 caused a substantial decrease in the potential symbiont and an enrichment of heterotrophic bacteria like Clostridium. A metagenomic analysis showed a selective effect of the high concentration treatment on the functional gene composition of the enriched heterotrophic bacteria, revealing an enrichment for the functions responsible for DNA repair, multidrug efflux pumping, and bacterial chemotaxis and motility. This study demonstrated that PBDE-47 induced a shift in the composition of the community and functional genes in the sponge-associated bacterial community, revealing the selective effect of PBDE-47 treatment on the functions of the bacterial community in the microenvironment of the sponge.

Time trends of polybrominated diphenyl ethers in East China Seas: Response to the booming of PBDE pollution industry in China.

Science.gov (United States)

Li, Yuanyuan; Lin, Tian; Hu, Limin; Feng, Jialiang; Guo, Zhigang

2016-01-01

The East China Seas (ECSs) are the receptors of the land-based persistent organic pollutants (POPs), such as polybrominated diphenyl ethers (PBDEs) mainly from China through atmospheric deposition driven by the East Asian winter monsoon and fluvial discharge (e.g., Yangtze River and Yellow River), making the offshore sediments to be a good proxy to reconstruct history of those pollutants in China. In this work, four well-placed sediment cores were extracted from the mud areas in the ECSs, and the (210)Pb-dated cores were analyzed to yield historical concentration profiles of PBDEs in the area. The results showed that there was a persistent increase from 1970s and almost no clear sign in the decline of PBDEs until recently in China. More importantly, there was a faster increase of PBDEs from 1990s in China; while this period was just shown as gradually leveling off or even declining trends in developed countries. The persistently increasing trend of PBDEs in China since 1990s could be largely due to the booming of the manufacturing industry and unexpectedly transfer of PBDE pollution from developed countries to China. Besides, the relative high concentrations and fluxes of PBDEs in the core from coastal ECS located near a well-known electrical/electronic waste (e-waste) recycling area suggests an important contribution of PBDE emissions from recycling centers of e-waste in China. Although efforts in environmental monitoring of PBDE contamination have been substantially increased over the last decade, China is still lagging behind in terms of nationwide regulation of PBDE usage and treatment of disposal PBDE-containing products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Occurrence and fate of PBDE in sewage sludge from municipal waste water treatment plants

Energy Technology Data Exchange (ETDEWEB)

Knoth, W.; Mann, W.; Meyer, R.; Nebhuth, J. [Federal Environmental Agency, POP Laboratory, Langen (Germany)

2004-09-15

With the rapidly growing use of combustible polymer material, e.g. for IT/TV casings, mattresses, upholstered furniture, the use of flame retardants like polybrominated diphenyl ether (PBDE) has also increased strongly. PBDE are available as three commercial mixtures of BDE congeners named after their principal component: PeBDE, OcBDE and DeBDE. They can release into the environment during their production, use or after disposal and have become ubiquitous. Because of (exponentially) increasing levels of the main congeners of technical Pe- and OcBDE in human blood and milk in Europe and California, the use and the placing on the market of preparations and articles containing these two flame retardants in concentrations >0.1% by mass are prohibited from August 15, 2004 in the European Union4 and in California from the year 2008. The main North American manufacturer of PeBDE flame retardant will voluntarily cease production by the end of 2004. For DeBDE a risk assessment is in progress. Surprising high levels were analysed in blood samples from 155 volunteers in the UK2 and a debromination to more bioavailable Hx- and HpBDE by juvenile carp (cyprinus carpio) following dietary exposure was observed. The objective of this study is to get more information about the actual levels and time trend of PBDE in sewage sludge in Germany and on a possible degradation of DeBDE by photolytic or reductive debromination during waste water treatment process.

Bar-coded pyrosequencing reveals the responses of PBDE-degrading microbial communities to electron donor amendments.

Directory of Open Access Journals (Sweden)

Meiying Xu

Full Text Available Polybrominated diphenyl ethers (PBDEs can be reductively degraded by microorganisms under anaerobic conditions. However, little is known about the effect of electron donors on microbial communities involved in PBDEs degradation. Here we employed 454 Titanium pyrosequencing to examine the phylogenetic diversity, composition, structure and dynamics of microbial communities from microcosms under the conditions of different electron donor amendments. The community structures in each of the five alternate electron donor enrichments were significantly shifted in comparison with those of the control microcosm. Commonly existing OTUs between the treatment and control consortia increased from 5 to 17 and more than 50% of OTUs increased around 13.7 to 186 times at least in one of the microcosms after 90-days enrichment. Although the microbial communities at different taxonomic levels were significantly changed by different environmental variable groups in redundancy analysis, significant correlations were observed between the microbial communities and PBDE congener profiles. The lesser-brominated PBDE congeners, tri-BDE congener (BDE-32 and hexa-BDE, were identified as the key factors shaping the microbial community structures at OTU level. Some rare populations, including the known dechlorinating bacterium, Dehalobacter, showed significant positive-correlation with the amounts of PBDE congeners in the consortia. The same results were also observed on some unclassified bacteria. These results suggest that PBDEs-degrading microbial communities can be successfully enriched, and their structures and compositions can be manipulated through adjusting the environmental parameters.

Temporal variability of polybrominated diphenyl ether (PBDE) serum concentrations over one year.

Science.gov (United States)

Makey, Colleen M; McClean, Michael D; Sjödin, Andreas; Weinberg, Janice; Carignan, Courtney C; Webster, Thomas F

2014-12-16

Polybrominated diphenyl ethers (PBDEs) are flame retardant chemicals used in consumer products. They are common contaminants in human serum and associated with adverse health effects. Our objectives were to characterize PBDE serum concentrations in a New England cohort and assess temporal variability of this exposure biomarker over a one-year period. We collected three repeated measurements at six-month intervals from 52 office workers from the greater Boston (MA, United States) area from 2010 to 2011. The intraclass correlation coefficient for BDEs 28, 47, 99, 100, and 153 ranged from 0.87 to 0.99, indicating that a single serum measurement can reliably estimate exposure over a one-year period. This was true for both lipid adjusted and nonlipid adjusted concentrations. The kappa statistics, quantifying the level of agreement of categorical exposure classification, based on medians, tertiles, or quartiles ranged from 0.67 to 0.90. Some congeners showed nonsignificant increases from sampling round 1 (winter) to round 2 (summer) and significant decreases from round 2 to round 3 (winter). This study highlights the high reliability of a single serum PBDE measurement for use in human epidemiologic studies.

Levels of polybrominated diphenyl ether (PBDE) flame retardants in animals representing different trophic levels of the North Sea food Web.

Science.gov (United States)

Boon, Jan P; Lewis, Wilma E; Tjoen-A-Choy, Michael R; Allchin, Colin R; Law, Robin J; De Boer, Jacob; Ten Hallers-Tjabbes, Cato C; Zegers, Bart N

2002-10-01

The levels of individual PBDE congeners were investigated in the invertebrate species whelk (Buccinum undatum), seastar (Asterias rubens), and hermit crab (Pagurus bernhardus), the gadoid fish species whiting (Merlangius merlangus) and cod (Gadus morhua), and the marine mammal species harbor seal (Phoca vitulina) and harbor porpoise (Phocoena phocoena). These species are all important representatives of different trophic levels of the North Sea food web. All six major PBDE congeners detected (BDEs 28, 47, 99, 100, 153, and 154) are most prevalent in the commercial Penta-BDE formulation. There is no evidence for the occurrence of the Octa-BDE formulation in the North Sea food web, since its dominant congener, BDE183, was never detected. BDE209, the main congener (> 97%) in the Deca-BDE formulation, was detected only in a minority of the samples and always in concentrations around the limit of detection. Since BDE209 is often the major BDE congener in sediments from the area, the main reason for its low concentrations in biota from the North Sea seems to be a relatively low bioaccumulation potential. This can either be due to a low uptake rate of the very large molecule or a relatively rapid excretion after biotransformation. Since all invertebrates investigated are sentinel species, they are highly representative for the area of capture. The highest lipid-normalized concentrations of PBDEs in the invertebrates occurred near the mouth of the river Tees at the East coast of the UK. The geographical distribution of the PBDEs can be explained by the residual currents in the area. The direction of these currents differs between the summer and the winter season as a result of the presence or absence of vertical summer stratification of the deeper waters north of the Dogger Bank. Summer stratification results in the development of a density-driven bottom water current formed after the onset of vertical stratification of the water column in May leaving the UK coast near

Biosynthesis of hydroxylated polybrominated diphenyl ethers and the correlation with photosynthetic pigments in the red alga Ceramium tenuicorne.

Science.gov (United States)

Lindqvist, Dennis; Dahlgren, Elin; Asplund, Lillemor

2017-01-01

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been identified in a variety of marine organisms from different trophic levels indicating a large spread in the environment. There is much evidence pointing towards natural production as the major source of these compounds in nature. However, much is still not known about the natural production of these compounds. Seasonal trend studies have shown large fluctuations in the levels of OH-PBDEs in Ceramium tenuicorne from the Baltic Sea. Yet, even though indications of stimuli that can induce the production of these compounds have been observed, none, neither internal nor external, has been assigned to be responsible for the recorded fluctuations. In the present study the possible relationship between the concentration of pigments and that of OH-PBDEs in C. tenuicorne has been addressed. Significant correlations were revealed between the concentrations of all OH-PBDEs quantified and the concentrations of both chlorophyll a and Σxanthophylls + carotenoids. All of which displayed a concentration peak in mid-July. The levels of OH-PBDEs may be linked to photosynthetic activity, and hence indirectly to photosynthetic pigments, via bromoperoxidase working as a scavenger for hydrogen peroxide formed during photosynthesis. Yet the large apparent investment in producing specific OH-PBDE congeners point towards an targeted production, with a more specific function than being a waste product of photosynthesis. The OH-PBDE congener pattern observed in this study is not agreeable with some currently accepted models for the biosynthesis of these compounds, and indicates a more selective route than previously considered in C. tenuicorne. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exposure to a PBDE/OH-BDE mixture alters juvenile zebrafish (Danio rerio) development.

Science.gov (United States)

Macaulay, Laura J; Chernick, Melissa; Chen, Albert; Hinton, David E; Bailey, Jordan M; Kullman, Seth W; Levin, Edward D; Stapleton, Heather M

2017-01-01

Polybrominated diphenyl ethers (PBDEs) and their metabolites (e.g., hydroxylated BDEs [OH-BDEs]) are contaminants frequently detected together in human tissues and are structurally similar to thyroid hormones. Thyroid hormones partially mediate metamorphic transitions between life stages in zebrafish, making this a critical developmental window that may be vulnerable to chemicals disrupting thyroid signaling. In the present study, zebrafish were exposed to 6-OH-BDE-47 (30 nM; 15 μg/L) alone, or to a low-dose (30 μg/L) or high-dose (600 μg/L) mixture of PentaBDEs, 6-OH-BDE-47 (0.5-6 μg/L), and 2,4,6-tribromophenol (5-100 μg/L) during juvenile development (9-23 d postfertilization) and evaluated for developmental endpoints mediated by thyroid hormone signaling. Fish were sampled at 3 time points and examined for developmental and skeletal morphology, apical thyroid and skeletal gene markers, and modifications in swimming behavior (as adults). Exposure to the high-dose mixture resulted in >85% mortality within 1 wk of exposure, despite being below reported acute toxicity thresholds for individual congeners. The low-dose mixture and 6-OH-BDE-47 groups exhibited reductions in body length and delayed maturation, specifically relating to swim bladder, fin, and pigmentation development. Reduced skeletal ossification was also observed in 6-OH-BDE-47-treated fish. Assessment of thyroid and osteochondral gene regulatory networks demonstrated significantly increased expression of genes that regulate skeletal development and thyroid hormones. Overall, these results indicate that exposures to PBDE/OH-BDE mixtures adversely impact zebrafish maturation during metamorphosis. Environ Toxicol Chem 2017;36:36-48. © 2016 SETAC. © 2016 SETAC.

PBDE exposure from food in Ireland: optimising data exploitation in probabilistic exposure modelling.

Science.gov (United States)

Trudel, David; Tlustos, Christina; Von Goetz, Natalie; Scheringer, Martin; Hungerbühler, Konrad

2011-01-01

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants added to plastics, polyurethane foam, electronics, textiles, and other products. These products release PBDEs into the indoor and outdoor environment, thus causing human exposure through food and dust. This study models PBDE dose distributions from ingestion of food for Irish adults on congener basis by using two probabilistic and one semi-deterministic method. One of the probabilistic methods was newly developed and is based on summary statistics of food consumption combined with a model generating realistic daily energy supply from food. Median (intermediate) doses of total PBDEs are in the range of 0.4-0.6 ng/kg(bw)/day for Irish adults. The 97.5th percentiles of total PBDE doses lie in a range of 1.7-2.2 ng/kg(bw)/day, which is comparable to doses derived for Belgian and Dutch adults. BDE-47 and BDE-99 were identified as the congeners contributing most to estimated intakes, accounting for more than half of the total doses. The most influential food groups contributing to this intake are lean fish and salmon which together account for about 22-25% of the total doses.

Hydroxylated polybrominated diphenyl ethers exhibit different activities on thyroid hormone receptors depending on their degree of bromination.

Science.gov (United States)

Ren, Xiao-Min; Guo, Liang-Hong; Gao, Yu; Zhang, Bin-Tian; Wan, Bin

2013-05-01

Polybrominated diphenyl ethers (PBDEs) have been shown to disrupt thyroid hormone (TH) functions in experimental animals, and one of the proposed disruption mechanisms is direct binding of hydroxylated PBDE (OH-PBDE) to TH receptors (TRs). However, previous data on TH receptor binding and TH activity of OH-PBDEs were very limited and sometimes inconsistent. In the present paper, we examined the binding potency of ten OH-PBDEs with different degrees of bromination to TR using a fluorescence competitive binding assay. The results showed that the ten OH-PBDEs bound to TR with potency that correlated to their bromination level. We further examined their effect on TR using a coactivator binding assay and GH3 cell proliferation assay. Different TR activities of OH-PBDEs were observed depending on their degree of bromination. Four low-brominated OH-PBDEs (2'-OH-BDE-28, 3'-OH-BDE-28, 5-OH-BDE-47, 6-OH-BDE-47) were found to be TR agonists, which recruited the coactivator peptide and enhanced GH3 cell proliferation. However, three high-brominated OH-PBDEs (3-OH-BDE-100, 3'-OH-BDE-154, 4-OH-BDE-188) were tested to be antagonists. Molecular docking was employed to simulate the interactions of OH-PBDEs with TR and identify the structural determinants for TR binding and activity. According to the docking results, low-brominated OH-PBDEs, which are weak binders but TR agonists, bind with TR at the inner side of its binding pocket, whereas high-brominated compounds, which are potent binders but TR antagonists, reside at the outer region. These results indicate that OH-PBDEs have different activities on TR (agonistic or antagonistic), possibly due to their different binding geometries with the receptor. Copyright © 2013 Elsevier Inc. All rights reserved.

Species-specific accumulation of polybrominated diphenyl ether flame retardants in birds of prey from the Chesapeake Bay region, USA

Energy Technology Data Exchange (ETDEWEB)

Chen Da, E-mail: chen@vims.ed [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Hale, Robert C. [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Watts, Bryan D. [Center for Conservation Biology, College of William and Mary, Williamsburg, VA 23185 (United States); La Guardia, Mark J.; Harvey, Ellen [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Mojica, Elizabeth K. [Center for Conservation Biology, College of William and Mary, Williamsburg, VA 23185 (United States)

2010-05-15

Compared to organochlorines, little is known about polybrominated diphenyl ether (PBDE) contamination of birds of prey breeding in the Chesapeake Bay, the largest estuary in the U.S. This study examined and compared PBDE contamination in eggs of osprey, double-crested cormorant, brown pelican and peregrine falcon from this area. Several legacy persistent organic pollutants such as PCBs and DDE were also investigated. The level of urbanization of the landscape appeared to influence the level of PBDE exposure. PBDE congener distribution patterns varied between piscivorous and terrestrial-feeding birds. This suggests individual congeners may be subject to differences in bioaccumulation, biomagnification or metabolism in the aquatic and terrestrial food webs. Biomagnification of PBDEs was studied in the Bay aquatic food chains for the first time. A biomagnification factor of 25.1 was estimated for SIGMAPBDEs for the fish - osprey egg food chain. Hazard quotients, applied as a preliminary evaluation, indicated that PBDEs may pose a moderate hazard to ospreys and peregrine falcons through impairment of reproductive performance. - Birds of prey breeding in the Chesapeake Bay (USA) exhibited species-specific PBDE accumulation patterns.

Species-specific accumulation of polybrominated diphenyl ether flame retardants in birds of prey from the Chesapeake Bay region, USA

International Nuclear Information System (INIS)

Chen Da; Hale, Robert C.; Watts, Bryan D.; La Guardia, Mark J.; Harvey, Ellen; Mojica, Elizabeth K.

2010-01-01

Compared to organochlorines, little is known about polybrominated diphenyl ether (PBDE) contamination of birds of prey breeding in the Chesapeake Bay, the largest estuary in the U.S. This study examined and compared PBDE contamination in eggs of osprey, double-crested cormorant, brown pelican and peregrine falcon from this area. Several legacy persistent organic pollutants such as PCBs and DDE were also investigated. The level of urbanization of the landscape appeared to influence the level of PBDE exposure. PBDE congener distribution patterns varied between piscivorous and terrestrial-feeding birds. This suggests individual congeners may be subject to differences in bioaccumulation, biomagnification or metabolism in the aquatic and terrestrial food webs. Biomagnification of PBDEs was studied in the Bay aquatic food chains for the first time. A biomagnification factor of 25.1 was estimated for ΣPBDEs for the fish - osprey egg food chain. Hazard quotients, applied as a preliminary evaluation, indicated that PBDEs may pose a moderate hazard to ospreys and peregrine falcons through impairment of reproductive performance. - Birds of prey breeding in the Chesapeake Bay (USA) exhibited species-specific PBDE accumulation patterns.

Trace Metals Bioaccumulation Potentials of Three Indigenous ...

African Journals Online (AJOL)

User

grasses as bioaccumulators of trace metals from polluted soils. Seeds of ... transfer factor (TF) showed that Zn was the most bioaccumulated trace metals by all the grasses followed by. Pb, Mn ... was used to de-contaminate copper (Cu) and.

Developmental exposure to PBDE 99 and PCB affects estrogen sensitivity of target genes in rat brain regions and female sexual behavior

Energy Technology Data Exchange (ETDEWEB)

Lichtensteiger, W; Faass, O; Ceccatelli, R; Schlumpf, M [Zurich Univ. (Switzerland). Inst. of Pharmacology and Toxicology

2004-09-15

We recently reported effects of PBDE99 (2,2',4,4'5-pentabromoBDE) on sexual differentiation processes in rat reproductive organs and central nervous system. These studies were prompted by reports on an increase of PBDE levels in human milk, an indicator of the body burden of pregnant women and of potential exposure of the nursing infant, during the last decade. Even higher human adipose tissue and milk levels were reported for North America. PBDE99 is present in human and animal samples and exhibits developmental neurotoxicity in mice. The developing brain is subject to the organizing action of estradiol locally formed from circulating testosterone, and thus represents a target for endocrine active chemicals. One molecular mechanism by which chemicals may interfere with sexual brain differentiation, may be a change in the expression of sex hormone (estrogen)-regulated genes. Such effects may manifest themselves in mRNA expression levels, or in the sensitivity of the genes to estrogen. In order to detect alterations of the latter, more subtle parameter, we have conducted experiments in developmentally chemical-exposed rat offspring that were gonadectomized in adulthood and injected with a challenge dose of estradiol. Effects of PBDE99 were compared with those of a commercial PCB mixture, Aroclor 1254, which had previously been found to influence sexual brain differentiation. We analyzed the expression of estrogen-regulated genes in ventromedial hypothalamus (VMH) and medial preoptic area (MPO), two brain regions that are part of a network involved in the integration of environmental cues, sexual behavior and gonadal function. Since prominent changes were observed in VMH which is particularly important for female sexual behavior, the study was completed by a behavioral analysis.

Exponential increases of the brominated flame retardants, polybrominated diphenyl ethers, in the Canadian Arctic from 1981 to 2000.

Science.gov (United States)

Ikonomou, Michael G; Rayne, Sierra; Addison, Richard F

2002-05-01

A suite of 37 polybrominated diphenyl ether (PBDE) congeners and all of the homologue groups from mono- to deca-brominated were determined in ringed seal (Phoca hispida) blubber collected from subsistence hunts in the Canadian Arctic in 1981, 1991, 1996, and 2000. Total PBDE (sum(PBDE)) concentrations have increased exponentially over this period in male ringed seals aged 0-15 years. Penta- and hexa-BDEs are increasing at approximately the same rate (t2 = 4.7 and 4.3 years, respectively) and more rapidly than tetra-BDEs (t2 = 8.6 years) and tri-BDEs (t2 = infinity) in this age/sex grouping. In contrast to declining PBDE concentrations since 1997 in human milk from Sweden, sum(PBDE) concentrations in arctic ringed seals continue to increase exponentially similar to worldwide commercial penta-BDE production. PBDE congener profiles in male ringed seals aged 0-15 years from 1991 to 2000 also differ significantly from other aquatic organisms and semipermeable membrane devices collected from temperate coastal regions of British Columbia. While PBDE concentrations are 50 times lower than those of mono-ortho and non-ortho PCBs, and approxiamately 500 times higher than PCDD/Fs, our data indicate that, at current rates of bioaccumulation, PBDEs will surpass PCBs to become the most prevalent organohalogen compound in Canadian arctic ringed seals by 2050.

Bioaccumulation in aquatic systems: methodological approaches, monitoring and assessment

DEFF Research Database (Denmark)

Schäfer, Sabine; Buchmeier, Georgia; Claus, Evelyn

2015-01-01

, various scientific and regulatory aspects of bioaccumulation in aquatic systems and the relevant critical issues are discussed. Monitoring chemical concentrations in biota can be used for compliance checking with regulatory directives, for identification of chemical sources or event-related environmental...... temporal and geographical range. Bioaccumulation is also assessed for regulation of chemicals of environmental concern whereby mainly data from laboratory studies on fish bioaccumulation are used. Field data can, however, provide additional important information for regulators. Strategies...... for bioaccumulation assessment still need to be harmonised for different regulations and groups of chemicals. To create awareness for critical issues and to mutually benefit from technical expertise and scientific findings, communication between risk assessment and monitoring communities needs to be improved...

Developmental exposure to PBDE 99 and PCB affects estrogen sensitivity of target genes in rat brain regions and female sexual behavior

Energy Technology Data Exchange (ETDEWEB)

Lichtensteiger, W.; Faass, O.; Ceccatelli, R.; Schlumpf, M. [Zurich Univ. (Switzerland). Inst. of Pharmacology and Toxicology

2004-09-15

We recently reported effects of PBDE99 (2,2',4,4'5-pentabromoBDE) on sexual differentiation processes in rat reproductive organs and central nervous system. These studies were prompted by reports on an increase of PBDE levels in human milk, an indicator of the body burden of pregnant women and of potential exposure of the nursing infant, during the last decade. Even higher human adipose tissue and milk levels were reported for North America. PBDE99 is present in human and animal samples and exhibits developmental neurotoxicity in mice. The developing brain is subject to the organizing action of estradiol locally formed from circulating testosterone, and thus represents a target for endocrine active chemicals. One molecular mechanism by which chemicals may interfere with sexual brain differentiation, may be a change in the expression of sex hormone (estrogen)-regulated genes. Such effects may manifest themselves in mRNA expression levels, or in the sensitivity of the genes to estrogen. In order to detect alterations of the latter, more subtle parameter, we have conducted experiments in developmentally chemical-exposed rat offspring that were gonadectomized in adulthood and injected with a challenge dose of estradiol. Effects of PBDE99 were compared with those of a commercial PCB mixture, Aroclor 1254, which had previously been found to influence sexual brain differentiation. We analyzed the expression of estrogen-regulated genes in ventromedial hypothalamus (VMH) and medial preoptic area (MPO), two brain regions that are part of a network involved in the integration of environmental cues, sexual behavior and gonadal function. Since prominent changes were observed in VMH which is particularly important for female sexual behavior, the study was completed by a behavioral analysis.

Complexity of Naturally Produced Polybrominated Diphenyl Ethers Revealed via Mass Spectrometry

Science.gov (United States)

Agarwal, Vinayak; Li, Jie; Rahman, Imran; Borgen, Miles; Aluwihare, Lihini I.; Biggs, Jason S.; Paul, Valerie J.; Moore, Bradley S.

2015-01-01

Polybrominated diphenyl ethers (PBDEs) are persistent and bioaccumulative anthropogenic and natural chemicals that are broadly distributed in the marine environment. PBDEs are potentially toxic due to inhibition of various mammalian signaling pathways and enzymatic reactions. PBDE isoforms vary in toxicity in accordance with structural differences, primarily in the number and pattern of hydroxyl moieties afforded upon a conserved core structure. Over four decades of isolation and discovery-based efforts have established an impressive repertoire of natural PBDEs. Based on our recent reports describing the bacterial biosyntheses of PBDEs, we predicted the presence of additional classes of PBDEs to those previously identified from marine sources. Using mass spectrometry and NMR spectroscopy, we now establish the existence of new structural classes of PBDEs in marine sponges. Our findings expand the chemical space explored by naturally produced PBDEs, which may inform future environmental toxicology studies. Furthermore, we provide evidence for iodinated PBDEs and direct attention toward the contribution of promiscuous halogenating enzymes in further expanding the diversity of these polyhalogenated marine natural products. PMID:25559102

A Sustainable Alternative to a Breast Milk Monitoring Program: Using NHANES Serum Data to Estimate Breast Milk PBDE Concentrations

Science.gov (United States)

Polybrominated diphenyl ethers (PBDEs) are high-production-volume chemicals that have been widely used as flame retardants in a variety of consumer products. PBDE concentrations in the environment, wildlife, and humans have been increasing for several decades. Concentrations in t...

21 CFR 172.814 - Hydroxylated lecithin.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxylated lecithin. 172.814 Section 172.814 Food... Multipurpose Additives § 172.814 Hydroxylated lecithin. The food additive hydroxylated lecithin may be safely... obtained by the treatment of lecithin in one of the following ways, under controlled conditions whereby the...

Current levels of primary polybrominated diphenyl ethers (PBDEs) in Norwegian seafood

Energy Technology Data Exchange (ETDEWEB)

Bethune, C.; Nielsen, J.; Julshamn, K. [National Institute of Nutrition and Seafood Research, Bergen (Norway)

2004-09-15

The brominated flame retardants (BFRs) represent major industrial chemicals whose use has increased dramatically over the past few decades. Polybrominated diphenyl ethers (PBDEs) are BFRs that are used in many types of consumer products. PBDEs have come to the attention of regulators and scientists due to their bioaccumulation, increasing exposure and persistence in the environment, and adverse health effects in animals and humans. Although PBDE contamination in marine fish was first detected in Sweden in 1979, and certain PBDEs are now banned as of this year, the European Union has yet to establish regulations on PBDE levels in either feed or seafood. The determination of these contaminants in consumer seafood is important for dietary exposure assessment and protection of human health. This study reports on the levels of 6 prominent PBDE congeners (28, 47, 99, 100, 153, and 154) in a selection of common Norwegian seafood.

Effect of developmental low dose PBDE 47 exposure on thyroid hormone status and serum concentrations of FSH and inhibin B in male rats

Energy Technology Data Exchange (ETDEWEB)

Andrade, A.J.M.; Kuriyama, S.N.; Akkoc, Z.; Talsness, C.E.; Chahoud, I. [Charite Univ. Medical School Berlin (Germany). Inst. of Clinical Pharmacology and Toxicology, Dept. Toxicology, Campus Benjamin Franklin

2004-09-15

Several persistent halogenated organic compounds such as PCBs, dioxins and more recently, polybrominated diphenyl ethers (PBDEs) have been shown to disrupt thyroid hormone homeostasis in experimental animals. Particular concern exists regarding exposure to these compounds during critical periods of development when thyroid hormones orchestrate the growth and differentiation of many organs including the brain and the testis. While the contamination levels of PCBs and other persistent organic pollutants have declined in the past years, increasing levels of PBDEs have been detected in environmental and human samples including human breast milk. PBDEs are produced in large quantities and used worldwide as flame retardants in electrical appliances, carpets and furniture upholstery. Similar to other halogenated environmental organic pollutants, PBDEs seem to present a wide range of toxic effects including reproductive, endocrine, neurobehavioral and hepatic toxicity. Recently, it has been demonstrated that in utero and pubertal exposures to DE-71 (a commercial mixture containing mostly tetra- and penta-bromodiphenyl ethers) significantly reduce thyroxine levels (T4) in rats. The present study has focused on the possible effects of the tetra- BDE congener 2,2'4,4'-tetrabromo diphenyl ether (PBDE 47) on thyroid hormone status and associated changes on FSH and inhibin B levels in the developing male rat. We administered a single dose to gravid dams on gestation day 6 of either 140 {mu}g/kg BW or 700 {mu}g/kg BW PBDE 47. These doses are pertinent to human exposure situation because a study by She et al.3 found a mean level of 33.3 {mu}g PBDE 47 /kg fat in human breast adipose tissue with a range from 7.01 to 196 {mu}g PBDE 47 /kg fat.

Quantification of hydroxyl radical produced during phacoemulsification.

Science.gov (United States)

Gardner, Jonathan M; Aust, Steven D

2009-12-01

To quantitate hydroxyl radicals produced during phacoemulsification with various irrigating solutions and conditions used in cataract surgery. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. All experiments were performed using an Infiniti Vision System phacoemulsifier with irrigation and aspiration. Hydroxyl radicals were quantitated using electron spin resonance spectroscopy and a spectrophotometric assay for malondialdehyde, which is formed by the oxidation of deoxyribose by the hydroxyl radical. Hydroxyl radical production increased during longitudinal-stroking phacoemulsification as power levels were increased in a nonlinear, nonexponential fashion. The detection of hydroxyl radical was reduced in irrigating solutions containing organic molecules (eg, citrate, acetate, glutathione, dextrose) and further reduced in Navstel, an irrigating solution containing a viscosity-modifying agent, hydroxypropyl methylcellulose. Hydroxyl radicals produced in settings representative of those used in phacoemulsification cataract surgery were quantitated using the deoxyribose method. Hydroxyl radical production was dependent on the level of ultrasound power applied and the irrigating solution used. Oxidative stress on the eye during phacoemulsification may be minimized by using irrigating solutions that contain organic molecules, including the viscosity-modifying agent hydroxypropyl methylcellulose, that can compete for reaction with hydroxyl radicals.

Prolyl hydroxylation in elastin is not random.

Science.gov (United States)

Schmelzer, Christian E H; Nagel, Marcus B M; Dziomba, Szymon; Merkher, Yulia; Sivan, Sarit S; Heinz, Andrea

2016-10-01

This study aimed to investigate the prolyl and lysine hydroxylation in elastin from different species and tissues. Enzymatic digests of elastin samples from human, cattle, pig and chicken were analyzed using mass spectrometry and bioinformatics tools. It was confirmed at the protein level that elastin does not contain hydroxylated lysine residues regardless of the species. In contrast, prolyl hydroxylation sites were identified in all elastin samples. Moreover, the analysis of the residues adjacent to prolines allowed the determination of the substrate site preferences of prolyl 4-hydroxylase. It was found that elastins from all analyzed species contain hydroxyproline and that at least 20%-24% of all proline residues were partially hydroxylated. Determination of the hydroxylation degrees of specific proline residues revealed that prolyl hydroxylation depends on both the species and the tissue, however, is independent of age. The fact that the highest hydroxylation degrees of proline residues were found for elastin from the intervertebral disc and knowledge of elastin arrangement in this tissue suggest that hydroxylation plays a biomechanical role. Interestingly, a proline-rich domain of tropoelastin (domain 24), which contains several repeats of bioactive motifs, does not show any hydroxyproline residues in the mammals studied. The results show that prolyl hydroxylation is not a coincidental feature and may contribute to the adaptation of the properties of elastin to meet the functional requirements of different tissues. The study for the first time shows that prolyl hydroxylation is highly regulated in elastin. Copyright © 2016 Elsevier B.V. All rights reserved.

Levels of Polybrominated Diphenyl Ether (PBDE) flame retardants in animals representing different trophic levels of the North Sea food web

NARCIS (Netherlands)

Boon, J.P.; Lewis, W.E.; Tjoen-A-Choy, M.R.; Allchin, C.R.; Law, R.J.; Boer, de J.

2002-01-01

The levels of individual PBDE congeners were investigated in the invertebrate species whelk (Buccinum undatum), seastar (Asterias rubens), and hermit crab (Pagurus bernhardus), the gadoid fish species whiting (Merlangius merlangus) and cod (Gadus morhua), and the marine mammal species harbor seal

Prolyl hydroxylation in elastin is not random

DEFF Research Database (Denmark)

Schmelzer, Christian E H; Nagel, Marcus B M; Dziomba, Szymon

2016-01-01

BACKGROUND: This study aimed to investigate the prolyl and lysine hydroxylation in elastin from different species and tissues. METHODS: Enzymatic digests of elastin samples from human, cattle, pig and chicken were analyzed using mass spectrometry and bioinformatics tools. RESULTS: It was confirmed...... at the protein level that elastin does not contain hydroxylated lysine residues regardless of the species. In contrast, prolyl hydroxylation sites were identified in all elastin samples. Moreover, the analysis of the residues adjacent to prolines allowed the determination of the substrate site preferences...... of prolyl 4-hydroxylase. It was found that elastins from all analyzed species contain hydroxyproline and that at least 20%-24% of all proline residues were partially hydroxylated. Determination of the hydroxylation degrees of specific proline residues revealed that prolyl hydroxylation depends on both...

Effect of polybrominated diphenyl ether (PBDE) treatment on the composition and function of the bacterial community in the sponge Haliclona cymaeformis.

KAUST Repository

Tian, Ren-Mao; Lee, On On; Wang, Yong; Cai, Lin; Bougouffa, Salim; Chiu, Jill Man Ying; Wu, Rudolf Shiu Sun; Qian, Pei-Yuan

2014-01-01

. In the present study, we studied the short-period effect of PBDE-47 (2,2',4,4'-tetrabromodiphenyl ether) treatment on the community structure and functional gene composition of the bacterial community inhabiting the marine sponge Haliclona cymaeformis. Our

Fish bioaccumulation and biomarkers in environmental risk assessment : a review

NARCIS (Netherlands)

van der Oost, Ron; Beyer, Jonny; Vermeulen, Nico P E

In this review, a wide array of bioaccumulation markers and biomarkers, used to demonstrate exposure to and effects of environmental contaminants, has been discussed in relation to their feasibility in environmental risk assessment (ERA). Fish bioaccumulation markers may be applied in order to

Bioaccumulation factors in aquatic ecosystems. A critical review

Energy Technology Data Exchange (ETDEWEB)

Karlsson, Sara; Meili, Markus; Bergstroem, Ulla [Studsvik Eco and Safety AB, Nykoeping (Sweden)

2002-07-01

The calculated concentrations of radionuclides in organisms are often obtained by means of bioaccumulation factors (BAF) that describe the internal concentration relative to an external concentration e.g. in the abiotic environments at steady-state conditions. Such factors are often used when modelling the dose to man from radio-nuclides released to the biosphere. Values of bioaccumulation factors vary widely in magnitude among elements, organisms, and environmental conditions which is not always considered. In order to relate the bioaccumulation factors for some radionuclides to environmental conditions as well as to the trophic level of the organism of concern we have compiled an extensive database with bioaccumulation factors (about 5,500 values) together with information on some environmental conditions. The data for nine radionuclides has been extracted and examined. A comparison between the bioaccumulation factors found in this study and values given in literature by IAEA and NCRP shows that the ranges presented in this study are generally somewhat higher with the exception of BAF for molybdenum in freshwater fish which is of the same order of magnitude. This is startling and calls for a thorough research. The amount of readily accessible and reliable values of BAF is limited, often because basic information such as e.g. units and part of organism examined, is not reported. This is surprising and also unfortunate for those who need such data for use in generic or specific models. A major update of recommended values appears to be necessary for many elements to account for the development of analytical methods and experiences from case studies over the past two decades.

Bioaccumulation factors in aquatic ecosystems. A critical review

International Nuclear Information System (INIS)

Karlsson, Sara; Meili, Markus; Bergstroem, Ulla

2002-07-01

The calculated concentrations of radionuclides in organisms are often obtained by means of bioaccumulation factors (BAF) that describe the internal concentration relative to an external concentration e.g. in the abiotic environments at steady-state conditions. Such factors are often used when modelling the dose to man from radio-nuclides released to the biosphere. Values of bioaccumulation factors vary widely in magnitude among elements, organisms, and environmental conditions which is not always considered. In order to relate the bioaccumulation factors for some radionuclides to environmental conditions as well as to the trophic level of the organism of concern we have compiled an extensive database with bioaccumulation factors (about 5,500 values) together with information on some environmental conditions. The data for nine radionuclides has been extracted and examined. A comparison between the bioaccumulation factors found in this study and values given in literature by IAEA and NCRP shows that the ranges presented in this study are generally somewhat higher with the exception of BAF for molybdenum in freshwater fish which is of the same order of magnitude. This is startling and calls for a thorough research. The amount of readily accessible and reliable values of BAF is limited, often because basic information such as e.g. units and part of organism examined, is not reported. This is surprising and also unfortunate for those who need such data for use in generic or specific models. A major update of recommended values appears to be necessary for many elements to account for the development of analytical methods and experiences from case studies over the past two decades

Phytotoxicity and bioavailablity of nickel: chemical speciation and bioaccumulation

NARCIS (Netherlands)

Weng, L.P.; Lexmond, T.M.; Wolthoorn, A.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

2003-01-01

The effect of pH on the bioaccumulation of nickel (Ni) by plants is opposite when using a nutrient solution or a soil as a growing medium. This paradox can be understood if the pH effect on the bioaccumulation, on the chemical speciation in the soil solution, and on the binding to the soil of Ni are

Selection of bioaccumulation criteria for environmental emergency (E2) planning

International Nuclear Information System (INIS)

Ketcheson, K.; Hradecky, K.; Gagne, M.; St-Amant-Verret, M.

2006-01-01

Environment Canada's Environmental Emergency regulations require the evaluation of a substance by a Risk Evaluation Framework (REF). Bioaccumulation criteria are used within the environmental hazard ratings section of the REF to determine the risk of a substance to organisms and are obtained from 3 types of measurements depending on data reliability: (1) bioaccumulation factors (BAF); (2) bioconcentration factors (BCF); and (3) an octanol-water partition coefficient (log K ow ). This paper presented details of a study of international and regional bioaccumulation criteria conducted to aid in determining appropriate criteria for E2 regulations and plans, with specific reference to substances toxic to aquatic organisms. An E2 plan is required if a substance has a bioconcentration factor of more than 500 in conjunction with aquatic toxicity. Bioaccumulation criteria from several sources for 745 substances were obtained to aid in choosing the most important parameters. Various international and regional criteria were examined and corresponding sources were summarized, and different source criteria was compared with empirical chemical data. The criteria chosen included both log K ow values and BCF values, although it was suggested that BCF and BAF are more realistic measures of bioaccumulation than log K ow , as they are derived from animal studies. The chosen values agreed with the virtual elimination criteria set out by the Canadian Environmental Protection Act (CEPA) 1999 as well as United States Environmental Protection Agency (EPA) criteria. It was concluded that the bioaccumulation criteria for E2 planning will help Environment Canada ensure the protection of the environment from hazardous substances. 11 refs., 3 tabs., 5 figs

Bioaccumulation and uptake routes of perfluoroalkyl acids in Daphnia magna.

Science.gov (United States)

Dai, Zhineng; Xia, Xinghui; Guo, Jia; Jiang, Xiaoman

2013-02-01

Perfluoroalkyl acids (PFAs), one kind of emerging contaminants, have attracted great attentions in recent years. However, the study about their bioaccumulation mechanism remains scarce. In this research, the bioaccumulation of six kinds of PFAs in water flea Daphnia magna was studied. The uptake rates of PFAs in D. magna ranged from 178 to 1338 L kg(-1) d(-1), and they increased with increasing perfluoroalkyl chain length; the elimination rates ranged from 0.98 to 2.82 d(-1). The bioaccumulation factors (BAFs) of PFAs ranged from 91 to 380 L kg(-1) in wet weight after 25 d exposure; they increased with increasing perfluoroalkyl chain length and had a significant positive correlation with the n-octanol/water partition coefficients (logK(ow)) of PFAs (pPFAs plays an important role in their bioaccumulation. The BAFs almost kept constant when the PFA concentrations in aqueous phase increased from 1 to 10 μg L(-1). Scenedesmus subspicatus, as the food of D. magna, did not significantly affect the bioaccumulation of PFAs by D. magna. Furthermore, the body burden of PFAs in the dead D. magna was 1.08-2.52 times higher than that in the living ones, inferring that the body surface sorption is a main uptake route of PFAs in D. magna. This study suggested that the bioaccumulation of PFAs in D. magna is mainly controlled by their partition between organisms and water; further research should be conducted to study the intrinsic mechanisms, especially the roles of protein and lipid in organisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Sustainable Alternative to a U.S. Breast Milk Monitoring Program: Using NHANES Serum Data to Estimate Breast Milk PBDE Concentrations

Science.gov (United States)

Polybrominated diphenyl ethers (PBDEs) are high-production-volume chemicals that have been widely used as flame retardants in a variety of consumer products. PBDE concentrations in the environment, wildlife, and humans have been increasing for several decades. Concentrations in t...

Bioaccumulation of decamethylcyclopentasiloxane in perch in Swedish lakes.

Science.gov (United States)

Kierkegaard, Amelie; Bignert, Anders; McLachlan, Michael S

2013-10-01

Decamethylcyclopentasiloxane (D5), a high production volume chemical used in personal care products, enters the environment both via air and sewage treatment plant (STP) recipients. It has been found in fish, and there is concern that it may be a bioaccumulative substance. In this work D5 was analyzed in perch from six Swedish lakes that did not receive STP effluent, and in perch and sediment from six lakes that received STP effluent. In the lakes receiving the STP effluent, the D5 concentrations in sediment varied over three orders of magnitude and were correlated with the number of persons connected to the STP normalized to the surface area of the receiving body. In the lakes not receiving effluent, the D5 levels in perch were all below the LOQ, while D5 was above the LOQ in almost all perch from lakes that received effluent. The D5 concentrations in perch and sediment from the lakes receiving STP effluent were correlated. This shows that STP effluent is a much more important source of D5 to aquatic ecosystems than atmospheric deposition, and that the risk of adverse effects of D5 on aquatic life will be greatest in small recipients receiving large amounts of STP effluent. The bioaccumulation of D5 was compared to that of PCB 180 on the basis of multimedia bioaccumulation factors (mmBAFs), which describe the fraction of the contaminant present in the whole aquatic environment (i.e. water and surface sediment) that is transferred to the fish. In four of the six lakes the mmBAF of D5 was >0.3 of the mmBAF of PCB 180. Given that PCB 180 is a known highly bioaccumulative chemical, this indicates that the bioaccumulation of D5 in perch is considerable. Copyright © 2012 Elsevier Ltd. All rights reserved.

Uptake and bioaccumulation of Cry toxins by an aphidophagous predator

International Nuclear Information System (INIS)

Paula, Débora P.; Andow, David A.

2016-01-01

Uptake of Cry toxins by insect natural enemies has rarely been considered and bioaccumulation has not yet been demonstrated. Uptake can be demonstrated by the continued presence of Cry toxin after exposure has stopped and gut contents eliminated. Bioaccumulation can be demonstrated by showing uptake and that the concentration of Cry toxin in the natural enemy exceeds that in its food. We exposed larvae of the aphidophagous predator, Harmonia axyridis, to Cry1Ac and Cry1F through uniform and constant tritrophic exposure via an aphid, Myzus persicae, and looked for toxin presence in the pupae. We repeated the experiment using only Cry1F and tested newly emerged adults. Both Cry toxins were detected in pupae, and Cry1F was detected in recently emerged, unfed adults. Cry1Ac was present 2.05 times and Cry1F 3.09 times higher in predator pupae than in the aphid prey. Uptake and bioaccumulation in the third trophic level might increase the persistence of Cry toxins in the food web and mediate new exposure routes to natural enemies. - Highlights: • Uptake and bioaccumulation of two Cry toxins by a larval coccinellid was tested. • Uptake was demonstrated by presence of the toxins in pupae and adults. • Bioaccumulation was shown by higher toxin concentration in pupae than prey. • Cry1Ac was present 2.05× and Cry1F 3.09× higher in predator pupae than prey. • This might increase persistence of Cry toxins in food webs with new exposure routes. - Immatures of the predaceous coccinellid Harmonia axyridis can uptake and bioaccumulate Cry toxins delivered via their aphid prey.

DNA Binding Hydroxyl Radical Probes.

Science.gov (United States)

Tang, Vicky J; Konigsfeld, Katie M; Aguilera, Joe A; Milligan, Jamie R

2012-01-01

The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different chromophores which produce fluorescent products when hydroxylated. Of these, the coumarin system suffers from the fewest disadvantages. We have therefore examined its behavior when linked to a cationic peptide ligand designed to bind strongly to DNA.

Assessing element-specific patterns of bioaccumulation across New England lakes

Energy Technology Data Exchange (ETDEWEB)

Ward, Darren M.; Mayes, Brandon; Sturup, Stefan; Folt, Carol L.; Chen, Celia Y., E-mail: celia.chen@dartmouth.edu

2012-04-01

Little is known about differences among trace elements in patterns of bioaccumulation in freshwater food webs. Our goal was to identify patterns in bioaccumulation of different elements that are large and consistent enough to discern despite variation across lakes. We measured methylmercury (MeHg) and trace element (As, Cd, Hg, Pb, and Zn) concentrations in food web components of seven New England lakes on 3-5 dates per lake, and contrasted patterns of bioaccumulation across lakes, metals and seasons. In each lake, trace element concentrations were compared across trophic levels, including three size fractions of zooplankton, planktivorous fish, and piscivorous fish. The trophic position of each food web component was estimated from N isotope analysis. Trace element concentrations varied widely among taxa, lakes and sampling dates. Yet, we identified four consistent patterns of bioaccumulation that were consistent across lakes: (1) MeHg concentration increased (i.e., was biomagnified) and Pb concentration decreased (i.e., was biodiminished) with increased trophic position. (2) Zinc concentration (as with MeHg) was higher in fish than in zooplankton, but overall variation in Zn concentration (unlike MeHg) was low. (3) Arsenic and Cd concentrations (as with Pb) were lower in fish than in zooplankton, but (unlike Pb) were not significantly correlated with trophic position within zooplankton or fish groups. (4) Average summer concentrations of As, Pb, Hg, and MeHg in zooplankton significantly predicted their concentrations in either planktivorous or piscivorous fish. Our secondary goal was to review sampling approaches in forty-five published studies to determine the extent to which current sampling programs facilitate cross-lake and cross-study comparisons of bioaccumulation. We found that studies include different components of the food web and sample too infrequently to enable strong cross-lake and cross-study comparisons. We discuss sampling strategies that would

Assessing element-specific patterns of bioaccumulation across New England lakes

International Nuclear Information System (INIS)

Ward, Darren M.; Mayes, Brandon; Sturup, Stefan; Folt, Carol L.; Chen, Celia Y.

2012-01-01

Little is known about differences among trace elements in patterns of bioaccumulation in freshwater food webs. Our goal was to identify patterns in bioaccumulation of different elements that are large and consistent enough to discern despite variation across lakes. We measured methylmercury (MeHg) and trace element (As, Cd, Hg, Pb, and Zn) concentrations in food web components of seven New England lakes on 3–5 dates per lake, and contrasted patterns of bioaccumulation across lakes, metals and seasons. In each lake, trace element concentrations were compared across trophic levels, including three size fractions of zooplankton, planktivorous fish, and piscivorous fish. The trophic position of each food web component was estimated from N isotope analysis. Trace element concentrations varied widely among taxa, lakes and sampling dates. Yet, we identified four consistent patterns of bioaccumulation that were consistent across lakes: (1) MeHg concentration increased (i.e., was biomagnified) and Pb concentration decreased (i.e., was biodiminished) with increased trophic position. (2) Zinc concentration (as with MeHg) was higher in fish than in zooplankton, but overall variation in Zn concentration (unlike MeHg) was low. (3) Arsenic and Cd concentrations (as with Pb) were lower in fish than in zooplankton, but (unlike Pb) were not significantly correlated with trophic position within zooplankton or fish groups. (4) Average summer concentrations of As, Pb, Hg, and MeHg in zooplankton significantly predicted their concentrations in either planktivorous or piscivorous fish. Our secondary goal was to review sampling approaches in forty-five published studies to determine the extent to which current sampling programs facilitate cross-lake and cross-study comparisons of bioaccumulation. We found that studies include different components of the food web and sample too infrequently to enable strong cross-lake and cross-study comparisons. We discuss sampling strategies that would

Fish bioaccumulation and biomarkers in environmental risk assessment: a review.

Science.gov (United States)

van der Oost, Ron; Beyer, Jonny; Vermeulen, Nico P E

2003-02-01

In this review, a wide array of bioaccumulation markers and biomarkers, used to demonstrate exposure to and effects of environmental contaminants, has been discussed in relation to their feasibility in environmental risk assessment (ERA). Fish bioaccumulation markers may be applied in order to elucidate the aquatic behavior of environmental contaminants, as bioconcentrators to identify certain substances with low water levels and to assess exposure of aquatic organisms. Since it is virtually impossible to predict the fate of xenobiotic substances with simple partitioning models, the complexity of bioaccumulation should be considered, including toxicokinetics, metabolism, biota-sediment accumulation factors (BSAFs), organ-specific bioaccumulation and bound residues. Since it remains hard to accurately predict bioaccumulation in fish, even with highly sophisticated models, analyses of tissue levels are required. The most promising fish bioaccumulation markers are body burdens of persistent organic pollutants, like PCBs and DDTs. Since PCDD and PCDF levels in fish tissues are very low as compared with the sediment levels, their value as bioaccumulation markers remains questionable. Easily biodegradable compounds, such as PAHs and chlorinated phenols, do not tend to accumulate in fish tissues in quantities that reflect the exposure. Semipermeable membrane devices (SPMDs) have been successfully used to mimic bioaccumulation of hydrophobic organic substances in aquatic organisms. In order to assess exposure to or effects of environmental pollutants on aquatic ecosystems, the following suite of fish biomarkers may be examined: biotransformation enzymes (phase I and II), oxidative stress parameters, biotransformation products, stress proteins, metallothioneins (MTs), MXR proteins, hematological parameters, immunological parameters, reproductive and endocrine parameters, genotoxic parameters, neuromuscular parameters, physiological, histological and morphological parameters

Prey species as possible sources of PBDE exposures for peregrine falcons (Falco peregrinus) nesting in major California cities.

Science.gov (United States)

Park, June-Soo; Fong, Alison; Chu, Vivian; Holden, Arthur; Linthicum, Janet; Hooper, Kim

2011-04-01

Our earlier findings indicate that (1) peregrine falcons (Falco peregrinus anatum Bonaparte) nesting in major California cities have among the highest polybrominated diphenyl ether (PBDE) levels in the world (max ∑PBDEs=100 ppm), and (2) Big City peregrines have higher levels and proportions of the higher-brominated congeners (hepta- to deca-BDEs) than do their Coastal counterparts. In this study we classified the prey species (n =185) from the remains of prey (feathers) at 38 peregrine nest sites over 25 years (1974-1998). We grouped the prey species into 15 categories based on diet and found distinctly different prey patterns for Big City vs. Coastal peregrines. Big City peregrines had a higher (almost three times) weight percentage intake of food waste-eating birds (e.g., rock pigeons, Columba livia) than Coastal peregrines. These differing prey patterns suggest diet as a potential source of the unusually high levels and proportions of higher-brominated PBDEs in Big City peregrines. The relative contributions of diet and dust (e.g., preening) exposure to PBDE patterns in Big City peregrines will be explored in future investigations. © Springer Science+Business Media, LLC 2010

Hydroxyl radical reactivity with diethylhydroxylamine

International Nuclear Information System (INIS)

Gorse, R.A. Jr.; Lii, R.R.; Saunders, B.B.

1977-01-01

Diethylhydroxylamine (DEHA) reacts with gas-phase hydroxyl radicals on every third collision, whereas the corresponding reaction in aqueous solution is considerably slower. The high gas-phase reactivity explains the predicted inhibitory effect of DEHA in atmospheric smog processes. Results from the studies in the aqueous phase are helpful in predicting the mechanism of the reaction of DEHA with hydroxyl radicals

Comparing trace metal bioaccumulation characteristics of three freshwater decapods of the genus Macrobrachium

Energy Technology Data Exchange (ETDEWEB)

Cresswell, Tom, E-mail: tom.cresswell@ansto.gov.au [Centre for Environmental Contaminants Research, CSIRO Land and Water, New Illawarra Rd, Lucas Heights, 2234, NSW (Australia); School of Applied Sciences, RMIT University, Plenty Road, Bundoora 3083, VIC (Australia); Smith, Ross E.W. [Hydrobiology, Lang Parade, Auchenflower 4066, QLD (Australia); Nugegoda, Dayanthi [School of Applied Sciences, RMIT University, Plenty Road, Bundoora 3083, VIC (Australia); Simpson, Stuart L. [Centre for Environmental Contaminants Research, CSIRO Land and Water, New Illawarra Rd, Lucas Heights, 2234, NSW (Australia)

2014-07-01

Highlights: • Exposed three species of prawns of same genus to solid- and dissolved-phase metals. • Cd bioaccumulated from dissolved phase was significantly different between species. • All three species retained >95% of bioaccumulated Cd during the depuration phase. • Bioaccumulation of As, Pb and Zn from solid phase was different between species. • Results highlight variability among species, even under controlled conditions. - Abstract: Potential sources and kinetics of metal bioaccumulation by the three Macrobrachium prawn species M. australiense, M. rosenbergii and M. latidactylus were assessed in laboratory experiments. The prawns were exposed to two scenarios: cadmium in water only; and exposure to metal-rich mine tailings in the same water. The cadmium accumulation from the dissolved exposure during 7 days, followed by depuration in cadmium-free water for 7 days, was compared with predictions from a biokinetic model that had previously been developed for M. australiense. M. australiense and M. latidactylus accumulated significant tissue cadmium during the exposure phase, albeit with different uptake rates. All three species retained >95% of the bioaccumulated cadmium during the depuration phase, indicating very slow efflux rates. Following exposure to tailings, there were significant (p < 0.05) differences in tissue arsenic, cadmium, lead and zinc concentrations among species. Cadmium and zinc concentrations were increased relative to controls for all three species but were not different between treatments (direct/indirect contact with tailings), suggesting these metals were primarily accumulated via the dissolved phase. All species bioaccumulated significantly greater arsenic and lead when in direct contact with mine tailings, demonstrating the importance of an ingestion pathway for these metals. Copper was not bioaccumulated above control concentrations for any species. The differences between the metal accumulation of the three prawns indicated

Role of metal mixtures (Ca, Cu and Pb) on Cd bioaccumulation and phytochelatin production by Chlamydomonas reinhardtii

International Nuclear Information System (INIS)

Abboud, Pauline; Wilkinson, Kevin J.

2013-01-01

The goal of the study was to determine whether metal uptake and biological effects could be predicted by free ion concentrations when organisms were exposed to Cd and a second metal. Bioaccumulation and algal phytochelatin (PC) concentrations were determined for Chlamydomonas reinhardtii following a 6-h exposure. Bioaccumulation results, after six hours of exposure, showed that Cd uptake decreased in the presence of relatively high concentrations of Ca, Cu and Pb, however, Cd bioaccumulation increased in the presence of ca. equimolar concentrations of Cu. A good correlation was observed between the production of PCs and the amount of metals bioaccumulated for the binary mixtures of Cd–Pb and Cd–Cu, but not the Cd–Ca mixture. Overall, the results suggested that, in the case of mixtures, bioaccumulated metal rather than free ion concentrations would be a better predictor of biological effect. -- Highlights: •Cd bioaccumulation and phytochelatin production were evaluated for metal mixtures. •Bioaccumulated metal rather than free ion was a better predictor of biological effect. •Calcium additions decreased Cd bioaccumulation but increased phytochelatin production. •Copper additions increased Cd bioaccumulation and phytochelatin production. •Lead additions had little effect on either Cd bioaccumulation or phytochelatin production. -- In metal mixtures containing Cd and Ca, Pb or Cu, bioaccumulated metal rather than free ion was a better predictor of biological effect

Uranium bioaccumulation in a freshwater ecosystem: Impact of feeding ecology

Energy Technology Data Exchange (ETDEWEB)

Kraemer, Lisa D., E-mail: lisakraemer@trentu.ca [Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8 (Canada); Evans, Douglas [Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8 (Canada)

2012-11-15

Uranium bioaccumulation in a lake that had been historically affected by a U mine and (2) to use a combined approach of gut content examination and stable nitrogen and carbon isotope analysis to determine if U bioaccumulation in fish was linked to foodweb ecology. We collected three species of fish: smallmouth bass (Micropterus dolomieu), yellow perch (Perca flavescens) and bluegill (Lepomis macrochirus), in addition to several invertebrate species including freshwater bivalves (family: Sphaeriidae), dragonfly nymphs (order: Odonata), snails (class: Gastropoda) and zooplankton (family: Daphniidae). Results showed significant U bioaccumulation in the lake impacted by historical mining activities. Uranium accumulation was 2-3 orders of magnitude higher in invertebrates than in the fish species. Within fish, U was measured in operculum (bone), liver and muscle tissue and accumulation followed the order: operculum > liver > muscle. There was a negative relationship between stable nitrogen ratios ({sup 15}N/{sup 14}N) and U bioaccumulation, suggesting U biodilution in the foodweb. Uranium bioaccumulation in all three tissues (bone, liver, muscle) varied among fish species in a consistent manner and followed the order: bluegill > yellow perch > smallmouth bass. Collectively, gut content and stable isotope analysis suggests that invertebrate-consuming fish species (i.e. bluegill) have the highest U levels, while fish species that were mainly piscivores (i.e. smallmouth bass) have the lowest U levels. Our study highlights the importance of understanding the feeding ecology of fish when trying to predict U accumulation.

The Dessau workshop on bioaccumulation: state of the art, challenges and regulatory implications.

Science.gov (United States)

Treu, Gabriele; Drost, Wiebke; Jöhncke, Ulrich; Rauert, Caren; Schlechtriem, Christian

2015-01-01

Bioaccumulation plays a vital role in understanding the fate of a substance in the environment and is key to the regulation of chemicals in several jurisdictions. The current assessment approaches commonly use the octanol-water partition coefficient (log K OW ) as an indicator for bioaccumulation and the bioconcentration factor (BCF) as a standard criterion to identify bioaccumulative substances show limitations. The log K OW does not take into account active transport phenomena or special structural properties (e.g., amphiphilic substances or dissociating substances) and therefore additional screening criteria are required. Regulatory BCF studies are so far restricted to fish and uptake through the gills. Studies on (terrestrial) air-breathing organisms are missing. Though there are alternative tests such as the dietary exposure bioaccumulation fish test described in the recently revised OECD test guideline 305, it still remains unclear how to deal with results of alternative tests in regulatory decision-making processes. A substantial number of bioaccumulation fish tests are required in regulation. The development of improved test systems following the 3R principles, namely to replace, reduce and refine animal testing, is thus required. All these aspects stress the importance to further develop the assessment of bioaccumulation. The Dessau Workshop on Bioaccumulation which was held from June 26th to 27th 2014, in Dessau, Germany, provided a comprehensive overview of the state of the art of bioaccumulation assessment, provided insights into the problems and challenges addressed by the regulatory authorities and described new research concepts and their regulatory implications. The event was organised by UBA (Dessau, Germany) and Fraunhofer IME (Schmallenberg, Germany). About 50 participants from industry, regulatory bodies and academia listened to 14 lectures on selected topics and joined the plenary discussions.

Cytochrome P450-dependent N-hydroxylation of an aminoguanidine (amidinohydrazone) and microsomal retroreduction of the N-hydroxylated product.

Science.gov (United States)

Clement, B; Schultze-Mosgau, M H; Richter, P H; Besch, A

1994-07-01

1. The first example of a P450-dependent N-hydroxylation of an aminoguanidine (amidinohydrazone) is reported for 2-amino-5-chlorobenzophenone amidinohydrazone 1 (G 256) as substrate. 2. The N-hydroxylated metabolite 2 (2-amino-5-chlorobenzophenone N-hydroxyamidinohydrazone NOH-G256) and a further metabolite of 1, the phenol 3, were identified by tlc and ms analysis. 3. The microsomal reduction of an N-hydroxyaminoguanidine (N-hydroxy-amidino-hydrazone) was also demonstrated for the transformation of 2 to 1. 4. Both the N-hydroxylation of the aminoguanidine and the retroreduction of the N-hydroxyaminoguanidine were characterized by quantitative hplc analysis. 5. The conversion of the aminoguanidine 1 to N-hydroxyaminoguanidine 2 may be considered as an analogue of the physiological N-hydroxylation of arginine to N-hydroxyarginine by NO synthases.

Biosorption and bioaccumulation of thallium by thallium-tolerant fungal isolates.

Science.gov (United States)

Sun, Jialong; Zou, Xiao; Xiao, Tangfu; Jia, Yanlong; Ning, Zengping; Sun, Min; Liu, Yizhang; Jiang, Tao

2015-11-01

Little is known about the biosorption and bioaccumulation capacity of thallium (Tl) by microorganisms that occur in Tl-polluted soil. The present study focused on characterizing the biosorption and bioaccumulation of Tl by Tl-tolerant fungi isolated from Tl-polluted soils. Preliminary data showed a positive correlation between the biomass and the biosorbed Tl content. The Tl-tolerant strains were capable of bioaccumulating Tl, up to 7189 mg kg(-1) dry weight. The subcellular distribution of Tl showed obvious compartmentalization: cytoplasm ≫ cell wall > organelle. The majority of Tl (up to 79%) was found in the cytoplasm, suggesting that intracellular compartmentalization appeared to be responsible for detoxification. These findings further suggest the applicability of the fungal isolates for cleanup of Tl in Tl-polluted water and soil.

Bioaccumulation versus adsorption of reactive dye by immobilized growing Aspergillus fumigatus beads

International Nuclear Information System (INIS)

Wang, B.-E.; Hu Yongyou

2008-01-01

The removal of reactive brilliant blue KN-R using growing Aspergillus fumigatus (abbr. A. fumigatus) immobilized on carboxymethylcellulose (CMC) beads with respect to initial dye concentration was investigated. Bioaccumulation was the dominant mechanism of the dye removal. According to the UV-vis spectra and the results of three sets of experiments, it could be concluded that the bioaccumulation using immobilized growing A. fumigatus beads was achieved by metabolism-dependent accumulation and metabolism-independent adsorption (15-23% proportion of overall dye removal), which included biosorption by mycelia entrapped in them and adsorption on immobilization matrix. The transmission electron microscope (TEM) images showed the intracellular structures of mycelia and the toxicity of dye. It was found that the fungus had a considerable tolerance to reactive brilliant blue KN-R at initial dye concentrations of <114.7 mg/l. Though at high initial dye concentrations the growth of mycelia was inhibited significantly by the dye molecules in the growth medium, the bioaccumulation capacity was not markedly affected and the maximum bioaccumulation capacity was 190.5 ± 2.0 mg/g at an initial dye concentration of 374.4 mg/l. The bioaccumulation rates were not constant over the contact time

Trait-based modelling of bioaccumulation by freshwater benthic invertebrates.

Science.gov (United States)

Sidney, Livia Alvarenga; Diepens, Noël J; Guo, Xiaoying; Koelmans, Albert A

2016-07-01

Understanding the role of species traits in chemical exposure is crucial for bioaccumulation and toxicity assessment of chemicals. We measured and modelled bioaccumulation of polychlorinated biphenyls (PCBs) in Chironomus riparius, Hyalella azteca, Lumbriculus variegatus and Sphaerium corneum. We used a battery test procedure with multiple enclosures in one aquarium, which maximized uniformity of exposure for the different species, such that the remaining variability was due mostly to species traits. The relative importance of uptake from either pore water or sediment ingestion was manipulated by using 28 d aged standard OECD sediment with low (1%) and medium (5%) OM content and 13 months aged sediment with medium OM (5%) content. Survival was ≥76% and wet weight increased for all species. Reproduction of H. azteca and weight gain of H. azteca and S. corneum were significantly higher in the medium OM aged sediments than in other sediments, perhaps due to a more developed microbial community (i.e., increase in food resources). Biota-sediment accumulation factors (BSAF) ranged from 3 to 114, depending on species and PCB congener, with C. riparius (3-10)bioaccumulation model with species-specific bioaccumulation parameters fitted well to the experimental data and showed that bioaccumulation parameters were depended on species traits. Enclosure-based battery tests and mechanistic BSAF models are expected to improve the quality of the exposure assessment in whole sediment toxicity tests. Copyright © 2016 Elsevier B.V. All rights reserved.

Heavy metal distribution and bioaccumulation in Chihuahuan Desert Rough Harvester ant (Pogonomyrmex rugosus) populations

International Nuclear Information System (INIS)

Del Toro, I.; Floyd, K.; Gardea-Torresdey, J.; Borrok, D.

2010-01-01

Heavy metal contamination can negatively impact arid ecosystems; however a thorough examination of bioaccumulation patterns has not been completed. We analyzed the distribution of As, Cd, Cu, Pb and Zn in soils, seeds and ant (Pogonomyrmex rugosus) populations of the Chihuahuan Desert near El Paso, TX, USA. Concentrations of As, Cd, Cu, and Pb in soils, seeds and ants declined as a function of distance from a now inactive Cu and Pb smelter and all five metals bioaccumulated in the granivorous ants. The average bioaccumulation factors for the metals from seeds to ants ranged from 1.04x (As) to 8.12x (Cd). The findings show bioaccumulation trends in linked trophic levels in an arid ecosystem and further investigation should focus on the impacts of heavy metal contamination at the community level. - Heavy metals bioaccumulate in desert ants.

Importance of growth rate on Hg and PCB bioaccumulation in fish

Science.gov (United States)

Li, Jiajia; Haffner, G. Douglas; Patterson, Gordon; Walters, David M.; Burtnyk, Michael D.; Drouillard, Ken G.

2018-01-01

To evaluate the effect of fish growth on mercury (Hg) and polychlorinated biphenyls (PCBs) bioaccumulation, a non‐steady state toxicokinetic model, combined with a Wisconsin bioenergetics model, was developed to simulate Hg and PCB bioaccumulation in Bluegill (Lepomis macrochirus). The model was validated by comparing observed versus predicted Hg and PCB 180 concentrations across 5 age classes from five different waterbodies across North America. The non‐steady state model generated accurate predictions for Hg and PCB bioaccumulation in three of five waterbodies: Apsey, Sharbot and Stonelick Lake. The poor performance of the model for the Detroit River and Lake Hartwell, which were two well‐known contaminated sites with possibly high heterogeneity in spatial contamination, was attributed to changes in the feeding behavior and/ or change in prey contamination. Model simulations indicate that growth dilution is a major component of contaminant bioaccumulation patterns in fish especially during early life stages and was predicted to be more important for hydrophobic PCBs compared to Hg. Simulations which considered tissue specific growth provided some improvement in model performance particularly for PCBs in fish populations which exhibited changes in their whole body lipid content with age. Higher variation in lipid growth compared with that of lean dry protein was also observed between different bluegill populations which partially explains the greater variation in PCB bioaccumulation slopes compared with Hg across sampling sites.

Bioaccumulation and chemical modification of Tc by soil bacteria

International Nuclear Information System (INIS)

Henrot, J.

1989-01-01

Bioaccumulation and chemical modification of pertechnetate (TcO 4 -) by aerobically and anaerobically grown soil bacteria and by pure cultures of sulfate-reducing bacteria (Desulfovibrio sp.) were studied to gain insight on the possible mechanisms by which bacteria can affect the solubility of Tc in soil. Aerobically grown bacteria had no apparent effect on TcO 4 -; they did not accumulate Tc nor modify its chemical form. Anaerobically grown bacteria exhibited high bioaccumulation and reduced TcO 4 -, enabling its association with organics of the growth medium. Reduction was a metabolic process and not merely the result of reducing conditions in the growth medium. Association of Tc with bacterial polysaccharides was observed only in cultures of anaerobic bacteria. Sulfate-reducing bacteria efficiently removed Tc from solution and promoted its association with organics. Up to 70% of the total Tc in the growth medium was bioaccumulated and/or precipitated. The remaining Tc in soluble form was entirely associated with organics. Pertechnetate was not reduced by the same mechanism as dissimilatory sulfate reduction, but rather by some reducing agent released in the growth medium. A calculation of the amount of Tc that could be associated with the bacterial biomass present in soil demonstrates that high concentration ratios in cultures do not necessarily imply that bioaccumulation is an important mechanism for long-term retention of Tc in soil

A closer look at bioaccumulation of petroleum hydrocarbon mixtures in aquatic worms.

NARCIS (Netherlands)

Muijs, B.; Jonker, M.T.O.

2010-01-01

Petroleum hydrocarbons (oils) are ubiquitous in the aquatic environment, and adequate risk assessment is thus essential. Bioaccumulation plays a key role in risk assessment, but the current knowledge on bioaccumulation of oils is limited. Therefore, this process was studied in detail, using the

Pollutant Dehalogenation Capability May Depend on the Trophic Evolutionary History of the Organism: PBDEs in Freshwater Food Webs

Science.gov (United States)

Bartrons, Mireia; Grimalt, Joan O.; de Mendoza, Guillermo; Catalan, Jordi

2012-01-01

Organohalogen compounds are some of the most notorious persistent pollutants disturbing the Earth biosphere. Although human-made, these chemicals are not completely alien to living systems. A large number of natural organohalogens, part of the secondary metabolism, are involved in chemical trophic interactions. Surprisingly, the relationship between organisms’ trophic position and synthetic organohalogen biotransformation capability has not been investigated. We studied the case for polybromodiphenyl ethers (PBDE), a group of flame-retardants of widespread use in the recent years, in aquatic food webs from remote mountain lakes. These relatively simple ecosystems only receive pollution by atmospheric transport. A large predominance of the PBDE congener currently in use in Europe, BDE-209, largely dominated the PBDE composition of the basal resources of the food web. In contrast, primary consumers (herbivores and detritivores) showed a low proportion of BDE-209, and dominance of several less brominated congeners (e.g. BDE-100, BDE47). Secondary consumers (predators) showed large biomagnification of BDE-209 compare to other congeners. Finally, top predator fish characterized by low total PBDE concentrations. Examination of the bromine stable isotopic composition indicates that primary consumers showed higher PBDE biotransformation capability than secondary consumers. We suggest that the evolutionary response of primary consumers to feeding deterrents would have pre-adapted them for PBDE biotransformation. The observed few exceptions, some insect taxa, can be interpreted in the light of the trophic history of the evolutionary lineage of the organisms. Bromine isotopic composition in fish indicates that low PBDE values are due to not only biotransformation but also to some other process likely related to transport. Our finding illustrates that organohalogen compounds may strongly disturb ecosystems even at low concentrations, since the species lacking or having

Pollutant dehalogenation capability may depend on the trophic evolutionary history of the organism: PBDEs in freshwater food webs.

Directory of Open Access Journals (Sweden)

Mireia Bartrons

Full Text Available Organohalogen compounds are some of the most notorious persistent pollutants disturbing the Earth biosphere. Although human-made, these chemicals are not completely alien to living systems. A large number of natural organohalogens, part of the secondary metabolism, are involved in chemical trophic interactions. Surprisingly, the relationship between organisms' trophic position and synthetic organohalogen biotransformation capability has not been investigated. We studied the case for polybromodiphenyl ethers (PBDE, a group of flame-retardants of widespread use in the recent years, in aquatic food webs from remote mountain lakes. These relatively simple ecosystems only receive pollution by atmospheric transport. A large predominance of the PBDE congener currently in use in Europe, BDE-209, largely dominated the PBDE composition of the basal resources of the food web. In contrast, primary consumers (herbivores and detritivores showed a low proportion of BDE-209, and dominance of several less brominated congeners (e.g. BDE-100, BDE47. Secondary consumers (predators showed large biomagnification of BDE-209 compare to other congeners. Finally, top predator fish characterized by low total PBDE concentrations. Examination of the bromine stable isotopic composition indicates that primary consumers showed higher PBDE biotransformation capability than secondary consumers. We suggest that the evolutionary response of primary consumers to feeding deterrents would have pre-adapted them for PBDE biotransformation. The observed few exceptions, some insect taxa, can be interpreted in the light of the trophic history of the evolutionary lineage of the organisms. Bromine isotopic composition in fish indicates that low PBDE values are due to not only biotransformation but also to some other process likely related to transport. Our finding illustrates that organohalogen compounds may strongly disturb ecosystems even at low concentrations, since the species lacking

Bioaccumulation of 14C-hexachlorobenzene in eggs and fry of Japanese medaka (Oryzias latipes)

International Nuclear Information System (INIS)

Huang, Y.; Biddinger, G.R.; Gloss, S.P.

1986-01-01

Hexachlorobenzene (HCB) is a widespread pollutant that is persistent once it enters the ecosphere. It bioaccumulates in both terrestrial and aquatic animals and is not readily metabolized. Although HCB bioaccumulation in fresh water fish has been reported, few data are available on bioaccumulation of this or other chemicals during early developmental stages of fish. The authors used the Japanese medaka (Oryzias latipes) to examine the rates of HCB bioaccumulation during early life stages subjected to both short term (24 h) and long term (14 day) aqueous exposure. The relatively rapid development and ease of laboratory maintenance made the medaka an ideal organism for this purpose

Explaining differences between Bioaccumulation Measurements in laboratory and field data through use of probabilistic modeling approach

NARCIS (Netherlands)

Selck, H.; Drouillard, K.; Eisenreich, K.; Koelmans, A.A.; Palmqvist, A.; Ruus, A.; Salvito, D.; Schultz, I.; Stewart, R.; Weisbrod, A.; Brink, van den N.W.; Heuvel-Greve, van den M.J.

2012-01-01

In the regulatory context, bioaccumulation assessment is often hampered by substantial data uncertainty as well as by the poorly understood differences often observed between results from laboratory and field bioaccumulation studies. Bioaccumulation is a complex, multifaceted process, which calls

DNA Binding Hydroxyl Radical Probes

OpenAIRE

Tang, Vicky J; Konigsfeld, Katie M; Aguilera, Joe A; Milligan, Jamie R

2012-01-01

The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different c...

Bioaccumulation Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010

Energy Technology Data Exchange (ETDEWEB)

Adams, Marshall [ORNL; Brandt, Craig C [ORNL; Fortner, Allison M [ORNL

2012-05-01

In December 2008, an ash dike at the Tennessee Valley Authority (TVA) Kingston Fossil Plant ruptured, releasing over one billion gallons of coal fly ash into the Emory and Clinch Rivers. Coal fly ash may contain several contaminants of concern, but of these selenium (Se) and arsenic (As) have been highlighted because of their toxicity and tendency to bioaccumulate in aquatic food chains. To assess the potential impact of the spilled fly ash on humans and the environment, a comprehensive biological and environmental monitoring program was established, for which resident aquatic organisms (among other sample media) are collected to determine contaminant exposure and evaluate the risk to humans and wildlife. Studies on bioaccumulation and fish health are major components of the TVA Biological Monitoring Program for the Kingston fly ash project. These studies were initiated in early Spring 2009 for the purposes of: (1) documenting the levels of fly ash-associated metals in various tissues of representative sentinel fish species in the area of the fly ash spill, (2) determining if exposure to fly ash-associated metals causes short, intermediate, or long-term health effects on these sentinel fish species, (3) assessing if there are causal relationships between exposure (to metals) and effects on fish, (4) evaluating, along with information regarding other ecological and physicochemical studies, the nature and route of contaminant transfer though food chains into higher level consumers, (5) providing important information for the Ecological Risk Assessment (ERA) for the Kingston fly ash project, and (6) serving as an important technology transfer or model study focused on how to best evaluate the environmental effects of fly ash, not only at the Kingston site, but also at sites on other aquatic systems where coal-fired generating stations are located. This report summarizes the bioaccumulation results from the first two years of study after the fly ash spill, including

Great Lakes water quality initiative technical support document for the procedure to determine bioaccumulation factors. Draft report

International Nuclear Information System (INIS)

1993-03-01

The purpose of the document is to provide the technical information and rationale in support of the proposed procedures to determine bioaccumulation factors. Bioaccumulation factors, together with the quantity of aquatic organisms eaten, determine the extent to which people and wildlife are exposed to chemicals through the consumption of aquatic organisms. The more bioaccumulative a pollutant is, the more important the consumption of aquatic organisms becomes as a potential source of contaminants to humans and wildlife. Bioaccumulation factors are needed to determine both human health and wildlife tier I water quality criteria and tier II values. Also, they are used to define Bioaccumulative Chemicals of Concern among the Great Lakes Initiative universe of pollutants. Bioaccumulation factors range from less than one to several million

Mercury in mercury(II)-spiked soils is highly susceptible to plant bioaccumulation.

Science.gov (United States)

Hlodák, Michal; Urík, Martin; Matúš, Peter; Kořenková, Lucia

2016-01-01

Heavy metal phytotoxicity assessments usually use soluble metal compounds in spiked soils to evaluate metal bioaccumulation, growth inhibition and adverse effects on physiological parameters. However, exampling mercury phytotoxicity for barley (Hordeum vulgare) this paper highlights unsuitability of this experimental approach. Mercury(II) in spiked soils is extremely bioavailable, and there experimentally determined bioaccumulation is significantly higher compared to reported mercury bioaccumulation efficiency from soils collected from mercury-polluted areas. Our results indicate this is not affected by soil sorption capacity, thus soil ageing and formation of more stable mercuric complexes with soil fractions is necessary for reasonable metal phytotoxicity assessments.

Cyclic volatile methylsiloxane bioaccumulation in flounder and ragworm in the Humber Estuary.

Science.gov (United States)

Kierkegaard, Amelie; van Egmond, Roger; McLachlan, Michael S

2011-07-15

Cyclic volatile methylsiloxanes are being subjected to regulatory scrutiny as possible PBT chemicals. The investigation of bioaccumulation has yielded apparently contradictory results, with high laboratory fish bioconcentration factors on the one hand and low field trophic magnification factors on the other. In this study, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) were studied along with polychlorinated biphenyls (PCBs) in sediments, ragworm, and flounder from six sites in the Humber Estuary. Bioaccumulation was evaluated using multimedia bioaccumulation factors (mmBAFs) which quantified the fraction of the contaminant present in the aquatic environment that is transferred to the biota. PCB 180, a known strongly bioaccumulative chemical, was used as a benchmark. The mean mmBAF of D5 was about twice that of PCB 180 in both polycheates and flounder, while for D4 it was 6 and 14 times higher, respectively. The mmBAF of D6 was a factor 5-10 lower than that of PCB180. The comparatively strong multimedia bioaccumulation of D4 and D5, even in the absence of biomagnification, was explained by both compounds having a >100 times stronger tendency to partition into lipid rather than into organic carbon, while PCB 180 partitions to a similar extent into both matrices.

Mercury bioaccumulation and elimination by Xenomelanires brasiliensis - radioactive tracers technique

International Nuclear Information System (INIS)

Malagrino, Waldir; Mesquita, Carlos Henrique de; Sousa, Eduinetty Ceci P.M. de

2002-01-01

The present work has as main objective to emphasized the importance of using radioactive tracers as well as to establish a methodology for the utilization of 203 Hg in the bioaccumulation study of mercury by X enomelanires brasiliensis. The exposure time was 168 hours. The bioaccumulation of mercury from the water as well as the elimination of the metal previously absorbed were determined by measuring the activity of 203 Hg, which was added to the water in the beginning of the experiments. The technique chosen is suitable to study the behavior of the stable mercury since the radioisotope used is an isotope of the same element and therefore presents the same chemical properties. The results obtained show that the absorption and elimination of mercury by Xenomelanires brasiliensis is slow, 168 hours being necessary for the elimination of 38 % of the previously absorbed mercury. The results are of main concern if it is considered that the literature about bioaccumulation of mercury by the Brazilian ichthyofauna is scarce. Furthermore the species Xenomelanires brasiliensis is part of the food chain and the results can be used in the evaluation of the potential risk of the mercury bioaccumulation by fishes of higher trophic levels and by men who are the final link of the food chain. (author)

A Nondestructive Method to Identify POP Contamination Sources in Omnivorous Seabirds.

Science.gov (United States)

Michielsen, Rosanne J; Shamoun-Baranes, Judy; Parsons, John R; Kraak, Michiel H S

2018-03-13

Persistent organic pollutants (POPs) are present in almost all environments due to their high bioaccumulation potential. Especially species that adapted to human activities, like gulls, might be exposed to harmful concentrations of these chemicals. The nature and degree of the exposure to POPs greatly vary between individual gulls, due to their diverse foraging behavior and specialization in certain foraging tactics. Therefore, in order clarify the effect of POP-contaminated areas on gull populations, it is important to identify the sources of POP contamination in individual gulls. Conventional sampling methods applied when studying POP contamination are destructive and ethically undesired. The aim of this literature review was to evaluate the potential of using feathers as a nondestructive method to determine sources of POP contamination in individual gulls. The reviewed data showed that high concentrations of PCBs and PBDEs in feathers together with a large proportion of less bioaccumulative congeners may indicate that the contamination originates from landfills. Low PCB and PBDE concentrations in feathers and a large proportion of more bioaccumulative congeners could indicate that the contamination originates from marine prey. We propose a nondestructive approach to identify the source of contamination in individual gulls based on individual contamination levels and PCB and PBDE congener profiles in feathers. Despite some uncertainties that might be reduced by future research, we conclude that especially when integrated with other methods like GPS tracking and the analysis of stable isotopic signatures, identifying the source of POP contamination based on congener profiles in feathers could become a powerful nondestructive method.

An investigation into ciguatoxin bioaccumulation in sharks.

Science.gov (United States)

Meyer, Lauren; Capper, Angela; Carter, Steve; Simpfendorfer, Colin

2016-09-01

Ciguatoxins (CTXs) produced by benthic Gambierdiscus dinoflagellates, readily biotransform and bioaccumulate in food chains ultimately bioconcentrating in high-order, carnivorous marine species. Certain shark species, often feeding at, or near the top of the food-chain have the ability to bioaccumulate a suite of toxins, from both anthropogenic and algal sources. As such, these apex predators are likely sinks for CTXs. This assumption, in conjunction with anecdotal knowledge of poisoning incidents, several non-specific feeding trials whereby various terrestrial animals were fed suspect fish flesh, and a single incident in Madagascar in 1994, have resulted in the widespread acceptance that sharks may accumulate CTXs. This prompted a study to investigate original claims within the literature, as well as investigate CTX bioaccumulation in the muscle and liver of 22 individual sharks from nine species, across four locations along the east coast of Australia. Utilizing an updated ciguatoxin extraction method with HPLC-MS/MS, we were unable to detect P-CTX-1, P-CTX-2 or P-CTX-3, the three primary CTX congeners, in muscle or liver samples. We propose four theories to address this finding: (1) to date, methods have been optimized for teleost species and may not be appropriate for elasmobranchs, or the CTXs may be below the limit of detection; (2) CTX may be biotransformed into elasmobranch-specific congeners as a result of unique metabolic properties; (3) 22 individuals may be an inadequate sample size given the rare occurrence of high-order ciguatoxic organisms and potential for CTX depuration; and (4) the ephemeral nature and inconsistent toxin profiles of Gambierdiscus blooms may have undermined our classifications of certain areas as CTX hotspots. These results, in combination with the lack of clarity within the literature, suggest that ciguatoxin bioaccumulation in sharks remains elusive, and warrants further investigation to determine the dynamics of toxin production

Bioaccumulation of zinc in foodstuffs by nuclear and related techniques

International Nuclear Information System (INIS)

Diaz Rizo, O.; Olivares Reumont, S.; Lima Cazorla, L.; Gelen Rudnikas, A.; D'Alessandro Rodriguez, K.; Arado Lopez, J. O.; Denis Alpizar, O.; Diaz Arado, O.; Viguri Fuente, J.

2011-01-01

The bioaccumulation of zinc in regular consumption foodstuff (sugar, rice, some vegetables, roots and shellfishes) in Cuba is reported. Zinc content in food samples and its corresponding soils or sediments are determined by Instrumental Neutron Activation analysis (INAA), X-Ray Fluorescence analysis (XRF), inductively coupled plasma emission spectrometry (ICP-AES) and Atomic Absorption spectrometry (AES). The obtained results show rice as the major Zn bioaccumulator of the studied products and the main Zn source in Cuban human diet. (Author)

Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation (IPSW)

Science.gov (United States)

This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) as it relates to organism bioaccumulation in the water column and interstitial water. Fifty-five studies were found where both passive samplers and organism bioaccumulation were used to measur...

BIOACCUMULATION AND AQUATIC SYSTEM SIMULATOR (BASS) USER'S MANUAL BETA TEST VERSION 2.1

Science.gov (United States)

BASS (Bioaccumulation and Aquatic System Simulator) is a Fortran 95 simulation program that predicts the population and bioaccumulation dynamics of age-structured fish assemblages that are exposed to hydrophobic organic pollutants and class B and borderline metals that complex wi...

Trophic transfer of naturally produced brominated aromatic compounds in a Baltic Sea food chain.

Science.gov (United States)

Dahlgren, Elin; Lindqvist, Dennis; Dahlgren, Henrik; Asplund, Lillemor; Lehtilä, Kari

2016-02-01

Brominated aromatic compounds (BACs) are widely distributed in the marine environment. Some of these compounds are highly toxic, such as certain hydroxylated polybrominated diphenyl ethers (OH-PBDEs). In addition to anthropogenic emissions through use of BACs as e.g. flame retardants, BACs are natural products formed by marine organisms such as algae, sponges, and cyanobacteria. Little is known of the transfer of BACs from natural producers and further up in the trophic food chain. In this study it was observed that total sum of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and OH-PBDEs increased in concentration from the filamentous red alga Ceramium tenuicorne, via Gammarus sp. and three-spined stickleback (Gasterosteus aculeatus) to perch (Perca fluviatilis). The MeO-PBDEs, which were expected to bioaccumulate, increased in concentration accordingly up to perch, where the levels suddenly dropped dramatically. The opposite pattern was observed for OH-PBDEs, where the concentration exhibited a general trend of decline up the food web, but increased in perch, indicating metabolic demethylation of MeO-PBDEs. Debromination was also indicated to occur when progressing through the food chain resulting in high levels of tetra-brominated MeO-PBDE and OH-PBDE congeners in fish, while some penta- and hexa-brominated congeners were observed to be the dominant products in the alga. As it has been shown that OH-PBDEs are potent disruptors of oxidative phosphorylation and that mixtures of different congener may act synergistically in terms of this toxic mode of action, the high levels of OH-PBDEs detected in perch in this study warrants further investigation into potential effects of these compounds on Baltic wildlife, and monitoring of their levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improving plant bioaccumulation science through consistent reporting of experimental data.

Science.gov (United States)

Fantke, Peter; Arnot, Jon A; Doucette, William J

2016-10-01

Experimental data and models for plant bioaccumulation of organic contaminants play a crucial role for assessing the potential human and ecological risks associated with chemical use. Plants are receptor organisms and direct or indirect vectors for chemical exposures to all other organisms. As new experimental data are generated they are used to improve our understanding of plant-chemical interactions that in turn allows for the development of better scientific knowledge and conceptual and predictive models. The interrelationship between experimental data and model development is an ongoing, never-ending process needed to advance our ability to provide reliable quality information that can be used in various contexts including regulatory risk assessment. However, relatively few standard experimental protocols for generating plant bioaccumulation data are currently available and because of inconsistent data collection and reporting requirements, the information generated is often less useful than it could be for direct applications in chemical assessments and for model development and refinement. We review existing testing guidelines, common data reporting practices, and provide recommendations for revising testing guidelines and reporting requirements to improve bioaccumulation knowledge and models. This analysis provides a list of experimental parameters that will help to develop high quality datasets and support modeling tools for assessing bioaccumulation of organic chemicals in plants and ultimately addressing uncertainty in ecological and human health risk assessments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metal Bioaccumulation by Estuarine Food Webs in New England, USA

Directory of Open Access Journals (Sweden)

Celia Y. Chen

2016-06-01

Full Text Available Evaluating the degree of metal exposure and bioaccumulation in estuarine organisms is important for understanding the fate of metals in estuarine food webs. We investigated the bioaccumulation of Hg, methylmercury (MeHg, Cd, Se, Pb, and As in common intertidal organisms across a watershed urbanization gradient of coastal marsh sites in New England to relate metal exposure and bioaccumulation in fauna to both chemical and ecological factors. In sediments, we measured metal and metalloid concentrations, total organic carbon (TOC and SEM-AVS (Simultaneously extracted metal-acid volatile sulfides. In five different functional feeding groups of biota, we measured metal concentrations and delta 15N and delta 13C signatures. Concentrations of Hg and Se in biota for all sites were always greater than sediment concentrations whereas Pb in biota was always lower. There were positive relationships between biota Hg concentrations and sediment concentrations, and between biota MeHg concentrations and both pelagic feeding mode and trophic level. Bioavailability of all metals measured as SEM-AVS or Benthic-Sediment Accumulation Factor was lower in more contaminated sites, likely due to biogeochemical factors related to higher levels of sulfides and organic carbon in the sediments. Our study demonstrates that for most metals and metalloids, bioaccumulation is metal specific and not directly related to sediment concentrations or measures of bioavailability such as AVS-SEM.

Modelling PCB bioaccumulation in a Baltic food web

International Nuclear Information System (INIS)

Nfon, Erick; Cousins, Ian T.

2007-01-01

A steady state model is developed to describe the bioaccumulation of organic contaminants by 14 species in a Baltic food web including pelagic and benthic aquatic organisms. The model is used to study the bioaccumulation of five PCB congeners of different chlorination levels. The model predictions are evaluated against monitoring data for five of the species in the food web. Predicted concentrations are on average within a factor of two of measured concentrations. The model shows that all PCB congeners were biomagnified in the food web, which is consistent with observations. Sensitivity analysis reveals that the single most sensitive parameter is log K OW . The most sensitive environmental parameter is the annual average temperature. Although not identified amongst the most sensitive input parameters, the dissolved concentration in water is believed to be important because of the uncertainty in its determination. The most sensitive organism-specific input parameters are the fractional respiration of species from the water column and sediment pore water, which are also difficult to determine. Parameters such as feeding rate, growth rate and lipid content of organism are only important at higher trophic levels. - The bioaccumulation behaviour of PCB congeners in a Baltic food web is studied using a novel mechanistic model

Bioaccumulation of 137Cs by culture collection strains of bacteria and fungi

International Nuclear Information System (INIS)

Pipiska, M.; Rozloznik, M.; Augustin, J.

2003-01-01

Soil decontamination of soil contaminated by low-level activities of radionuclides, mainly by caesium-137, which come from accidental releases by maintenance of nuclear devices and by liquid wastes reprocessing, is long-term and expensive technology. Knowledge of the causations, which control the processes of bioaccumulation of radionuclides, is a necessary condition for critical assessment and successful utilization of processes of bioremediation in situ in practise. The authors present the experimentally gained quantitative values of bioaccumulation of caesium-137 from water solutions by micro organism cultures of Rhodotorula aurantiaca CCY 20-9-1, Sacharomyces cerevisiae, Rhodococcus rhodochrous ATCC 15906, Streptomyces sp. DX-IX, Coriolus versicolor CCWDF-14 and Rhizopus sp. R-18. Intensively growing cultures reach the highest values of bioaccumulation; the cultures in non-growing phase reach several orders lower values. From researched micro organisms the highest values of bioaccumulation of Cs + 5.1 pmol/g (wet weight) at initial concentration of Cs + in solution co = 1 nmol/l (without carrier) and 29.2 μmol/g (wet weight) at co = 6 mmol/l Cs + (adding of carrier CsCl) were found out at growing culture S. cerevisiae as model of eukaryotic cell after an achievement of maximal stationary grow phase. Acquired information refer to the possible role of soil micro organisms at bioaccumulation of 137 Cs in contaminated soils and their potential utilization in lowering of radioactive contamination of environment (authors)

Importance of growth rate on mercury and polychlorinated biphenyl bioaccumulation in fish

Science.gov (United States)

Li, Jiajia; Haffner, G. Douglas; Patterson, Gordon; Walters, David M.; Burtnyk, Michael D.; Drouillard, Ken G.

2018-01-01

To evaluate the effect of fish growth on mercury (Hg) and polychlorinated biphenyl (PCB) bioaccumulation, a non–steady‐state toxicokinetic model, combined with a Wisconsin bioenergetics model, was developed to simulate Hg and PCB bioaccumulation in bluegill (Lepomis macrochirus). The model was validated by comparing observed with predicted Hg and PCB 180 concentrations across 5 age classes from 5 different waterbodies across North America. The non–steady‐state model generated accurate predictions for Hg and PCB bioaccumulation in 3 of 5 waterbodies: Apsey Lake (ON, Canada), Sharbot Lake (ON, Canada), and Stonelick Lake (OH, USA). The poor performance of the model for the Detroit River (MI, USA/ON, Canada) and Lake Hartwell (GA/SC, USA), which are 2 well‐known contaminated sites with possibly high heterogeneity in spatial contamination, was attributed to changes in feeding behavior and/or prey contamination. Model simulations indicate that growth dilution is a major component of contaminant bioaccumulation patterns in fish, especially during early life stages, and was predicted to be more important for hydrophobic PCBs than for Hg. Simulations that considered tissue‐specific growth provided some improvement in model performance particularly for PCBs in fish populations that exhibited changes in their whole‐body lipid content with age. Higher variation in lipid growth compared with that of lean dry protein was also observed between different bluegill populations, which partially explains the greater variation in PCB bioaccumulation slopes compared with Hg across sampling sites.

A biodynamic model predicting waterborne lead bioaccumulation in Gammarus pulex: Influence of water chemistry and in situ validation

International Nuclear Information System (INIS)

Urien, N.; Uher, E.; Billoir, E.; Geffard, O.; Fechner, L.C.; Lebrun, J.D.

2015-01-01

Metals bioaccumulated in aquatic organisms are considered to be a good indicator of bioavailable metal contamination levels in freshwaters. However, bioaccumulation depends on the metal, the species, and the water chemistry that influences metal bioavailability. In the laboratory, a kinetic model was used to describe waterborne Pb bioaccumulated in Gammarus pulex. Uptake and elimination rate constants were successfully determined and the effect of Ca 2+ on Pb uptake was integrated into the model. Thereafter, accumulated Pb concentrations in organisms were predicted with the model and compared with those measured in native populations from the Seine watershed (France). The predictions had a good agreement with the bioaccumulation levels observed in native gammarids and particularly when the effect of calcium was considered. To conclude, kinetic parameters experimentally derived for Pb in G. pulex are applicable in environmental conditions. Moreover, the consideration of the water's chemistry is crucial for a reliable interpretation of bioaccumulation. - Highlights: • Kinetic model was used to describe waterborne Pb bioaccumulation in G. pulex. • Ca 2+ inhibits Pb uptake by G. pulex in the laboratory. • Model predictions were compared to bioaccumulated Pb in native G. pulex. • Model accurately predicts waterborne bioaccumulated Pb in gammarids. • Considering the influence of Ca 2+ improves the model predictions in the field. - An experimentally-derived kinetic model considering the effect of calcium was relevant to predict the waterborne Pb bioaccumulation in native Gammarus pulex

Bioaccumulation of short chain chlorinated paraffins in a typical freshwater food web contaminated by e-waste in south china: Bioaccumulation factors, tissue distribution, and trophic transfer.

Science.gov (United States)

Sun, Runxia; Luo, Xiaojun; Tang, Bin; Chen, Laiguo; Liu, Yu; Mai, Bixian

2017-03-01

Short chain chlorinated paraffins (SCCPs) are under review for inclusion into the Stockholm Convention on Persistent Organic Pollutants. However, limited information is available on their bioaccumulation and biomagnification in ecosystems, which is hindering evaluation of their ecological and health risks. In the present study, wild aquatic organisms (fish and invertebrates), water, and sediment collected from an enclosed freshwater pond contaminated by electronic waste (e-waste) were analyzed to investigate the bioaccumulation, distribution, and trophic transfer of SCCPs in the aquatic ecosystem. SCCPs were detected in all of the investigated aquatic species at concentrations of 1700-95,000 ng/g lipid weight. The calculated bioaccumulation factors (BAFs) varied from 2.46 to 3.49. The relationship between log BAF and the octanol/water partition coefficient (log K OW ) for benthopelagic omnivorous fish species followed the empirical model of bioconcentration, indicating that bioconcentration plays an important role in accumulation of SCCPs. In contrast, the relationship for the benthic carnivorous fish and invertebrates was not consistent with the empirical model of bioconcentration, implying that the bioaccumulation of SCCPs in these species could be more influenced by other complex factors (e.g., habitat and feeding habit). Preferential distribution in the liver rather than in other tissues (e.g., muscle, gills, skin, and kidneys) was noted for the SCCP congeners with higher log K OW , and bioaccumulation pathway (i.e. water or sediment) can affect the tissue distribution of SCCP congeners. SCCPs underwent trophic dilution in the aquatic food web, and the trophic magnification factor (TMF) values of SCCP congener groups significantly correlated with their corresponding log K OW values (p < 0.0001). The present study results improved our understanding on the environmental behavior and fate of SCCPs in aquatic ecosystem. Copyright © 2016 Elsevier Ltd. All rights

PCB and PBDE levels in a highly threatened dolphin species from the Southeastern Brazilian coast

International Nuclear Information System (INIS)

Lavandier, Ricardo; Arêas, Jennifer; Quinete, Natalia; Moura, Jailson F. de; Taniguchi, Satie; Montone, Rosalinda; Siciliano, Salvatore; Moreira, Isabel

2016-01-01

In the Northern coast of Rio de Janeiro State is located the major urban centers of the oil and gas industry of Brazil. The intense urbanization in recent decades caused an increase in human use of the coastal areas, which is constantly impacted by agricultural, industrial and wastewater discharges. Franciscana dolphin (Pontoporia blainvillei) is a small cetacean that inhabits coastal regions down to a 30 m depth. This species is considered the most threatened cetacean in the Western South Atlantic Ocean. This study investigated the levels of 52 PCB congeners and 9 PBDE congeners in liver of nine individuals found stranded or accidentally caught between 2011 and 2012 in the Northern coast of Rio de Janeiro. PCB mean levels ranged from 208 to 5543 ng g"−"1 lw and PBDEs mean concentrations varied between 13.84 and 36.94 ng g"−"1 lw. Contamination patterns suggest the previous use of Aroclor 1254, 1260 and penta-BDE mixtures in Brazil. While still few studies have assessed the organic contamination in cetaceans from the Southern Hemisphere, including Brazil, the levels found in this study could represent a health risk to these endangered species. - Highlights: • PCBs and PBDEs were measured in liver samples from Franciscana dolphins. • BDE 47, 99 and 100 were found in all individuals samples. • PCB-153, 138 and 180 were the major PCB congeners detected. • Results suggest the existence of PCBs and PBDEs contamination sources in Brazil. • PCBs and PDBEs levels could represent a risk to these endangered dolphin species. - PCB and PBDE concentrations found in Franciscana dolphins suggest the presence of contamination sources in Southeastern Brazil and could represent a high health risk to these endangered species.

Methylmercury bioaccumulation in an urban estuary: Delaware River USA.

Science.gov (United States)

Buckman, Kate; Taylor, Vivien; Broadley, Hannah; Hocking, Daniel; Balcom, Prentiss; Mason, Rob; Nislow, Keith; Chen, Celia

2017-09-01

Spatial variation in mercury (Hg) and methylmercury (MeHg) bioaccumulation in urban coastal watersheds reflects complex interactions between Hg sources, land use, and environmental gradients. We examined MeHg concentrations in fauna from the Delaware River estuary, and related these measurements to environmental parameters and human impacts on the waterway. The sampling sites followed a north to south gradient of increasing salinity, decreasing urban influence, and increasing marsh cover. Although mean total Hg in surface sediments (top 4cm) peaked in the urban estuarine turbidity maximum and generally decreased downstream, surface sediment MeHg concentrations showed no spatial patterns consistent with the examined environmental gradients, indicating urban influence on Hg loading to the sediment but not subsequent methylation. Surface water particulate MeHg concentration showed a positive correlation with marsh cover whereas dissolved MeHg concentrations were slightly elevated in the estuarine turbidity maximum region. Spatial patterns of MeHg bioaccumulation in resident fauna varied across taxa. Small fish showed increased MeHg concentrations in the more urban/industrial sites upstream, with concentrations generally decreasing farther downstream. Invertebrates either showed no clear spatial patterns in MeHg concentrations (blue crabs, fiddler crabs) or increasing concentrations further downstream (grass shrimp). Best-supported linear mixed models relating tissue concentration to environmental variables reflected these complex patterns, with species specific model results dominated by random site effects with a combination of particulate MeHg and landscape variables influencing bioaccumulation in some species. The data strengthen accumulating evidence that bioaccumulation in estuaries can be decoupled from sediment MeHg concentration, and that drivers of MeHg production and fate may vary within a small region.

Biomonitoring of Danish school children and mothers including biomarkers of PBDE and glyphosate

DEFF Research Database (Denmark)

Knudsen, Lisbeth E.; Hansen, Pernille Winton; Mizrak, Seher

2017-01-01

Danish school children aged 6–11 years and their mothers from rural and urban areas in autumn 2011. Some – but not all – results were published; however, the concurrence of the chemicals has not been assessed. Methods: The measured concentrations of polybrominated diphenyl ethers (PBDEs) and glyphosate...... is assessed to complete the investigation of all 66 chemicals in DEMOCOPHES. The concentrations of PBDEs were measured in plasma samples of 143 mothers and 116 children. Glyphosate was measured in a subsample of 27 urine samples. Previously assessed chemicals were polychlorinated biphenyls (PCBs...... the concentrations of the different environmental chemicals. investigated by correlation analysis. Results: PBDE47 was found in relatively high levels compared with previous Danish results in both mothers and children, with a significantly higher level in the children compared to their mothers. Glyphosate...

Bioaccumulation factor of 137Cs in some marine biotas from West Bangka Indonesia

Science.gov (United States)

Suseno, Heny

2014-03-01

Radionuclides may be released from nuclear facilities to the marine environment. Concentrations of radionuclides within marine biotic systems can be influenced by a number of factors, including the type of biota, its source, the radionuclide, and specific characteristics of the sampled specimens and the marine environment (salinity, etc.). The bioconcentration factor for a marine organism is the ratio of the concentration of a radionuclide in that organism to the concentration found in its marine water environment - under conditions of equilibrium. Information on the bioaccumulation of Cs-137 in marine organisms is required to risk assessment evaluates the potential risks to human health. Bioaccumulation of Cs was investigated in marine biota from west Bangka such as Marine cat fish (Arius thalassinus), Baramundi (Lates calcarifer), Mackerel (Scomberomorus commerson), Striped eel catfish (Plotosus lineatus), eel tailed fish (Euristhmus microceps), Yellowtail fusilier (Caesio erythrogaster), Coastal crab (Scylla sp), White shrimp (Penaeus merguiensis) and marine bivalve mollusk (Anadara granosa). Muscle of these marine biota, sediments and water were assayed for Cs-137 by HPGe gamma spectrometer. The bioaccumulation factor for fishes were calculated by ratio of concentration Cs-137 in muscle biota to the its concentration in water. The bioaccumulation factor for mollusks were calculates by ratio of concentration Cs-137 in muscle biota to the its concentration in sediments. The bioaccumulation factor were range 4.99 to 136.34.

Bioaccumulation factor of 137Cs in some marine biotas from West Bangka Indonesia

International Nuclear Information System (INIS)

Suseno, Heny

2014-01-01

Radionuclides may be released from nuclear facilities to the marine environment. Concentrations of radionuclides within marine biotic systems can be influenced by a number of factors, including the type of biota, its source, the radionuclide, and specific characteristics of the sampled specimens and the marine environment (salinity, etc.). The bioconcentration factor for a marine organism is the ratio of the concentration of a radionuclide in that organism to the concentration found in its marine water environment - under conditions of equilibrium. Information on the bioaccumulation of Cs-137 in marine organisms is required to risk assessment evaluates the potential risks to human health. Bioaccumulation of Cs was investigated in marine biota from west Bangka such as Marine cat fish (Arius thalassinus), Baramundi (Lates calcarifer), Mackerel (Scomberomorus commerson), Striped eel catfish (Plotosus lineatus), eel tailed fish (Euristhmus microceps), Yellowtail fusilier (Caesio erythrogaster), Coastal crab (Scylla sp), White shrimp (Penaeus merguiensis) and marine bivalve mollusk (Anadara granosa). Muscle of these marine biota, sediments and water were assayed for Cs-137 by HPGe gamma spectrometer. The bioaccumulation factor for fishes were calculated by ratio of concentration Cs-137 in muscle biota to the its concentration in water. The bioaccumulation factor for mollusks were calculates by ratio of concentration Cs-137 in muscle biota to the its concentration in sediments. The bioaccumulation factor were range 4.99 to 136.34

The bioaccumulation factor for phosphorus-32 in edible fish tissue. Final report 1 Aug 77-15 Oct 79

International Nuclear Information System (INIS)

Kaho, B.; Turgeon, K.

1980-03-01

Information used to derive the bioaccumulation factor for P-32 in edible portions of fish from water was reviewed to evaluate the currently recommended values of 100,000 in fresh water and 29,000 in sea water that are applied in generic calculations of radiation doses to persons from nuclear power reactor effluents. A phosphorus bioaccumulation factor of 70,000 was calculated for larger rivers and estuarine waters on the basis of geometric mean phosphorus concentrations of 2 mg/g wet weight in fish muscle and 0.03 mg/1 dissolved in water. A bioaccumulation factor for P-32 of 3,000 was computed by multiplying the phosphorus bioaccumulation factor by the ratio of the biological to the effective turnover rate in fish muscle. A biological turnover rate in muscle of 0.2 percent per day was estimated from phosphorus balances as a long-term average for large fish, although more rapid turnovers have been observed for brief periods. Large deviations from these selected generic bioaccumulation factors occur because of differences in phosphorus concentrations and turnover rates. Bioaccumulation of this magnitude is due to P-32 concentration at lowest trophic levels in the food web, not by concentration in fish, hence the availability of concentrating organisms determines whether this bioaccumulation factor is reached. Several other conditions that affect the P-32 bioaccumulation factor have not been quantified but are suggested for study. Measurement programs are recommended to determine site-specific P-32 bioaccumulation factors and enlarge the data base for the generic values

Mercury bioaccumulation in the Mediterranean

Directory of Open Access Journals (Sweden)

Cinnirella S.

2013-04-01

Full Text Available This study details mercury pollution within the food chain of the Mediterranean by analysing the most comprehensive mercury dataset available for biota and water measurements. In this study we computed a bioaccumulation factor (BAF for datasets in the existing mercury-related scientific literature, in on-going programs, and in past measurement campaigns. Preliminary results indicate a major lack of information, making the outcome of any assessment very uncertain. Importantly, not all marine eco-regions are (or have ever been covered by measurement campaigns. Most lacking is information associated with the South-Eastern part of the Mediterranean, and in several eco-regions it is still impossible to reconstruct a trophic net, as the required species were not accounted for when mercury measurements were taken. The datasets also have additional temporal sampling problems, as species were often not sampled systematically (but only sporadically during any given sampling period. Moreover, datasets composed of mercury concentrations in water also suffer from similar geographic limitations, as they are concentrated in the North-Western Mediterranean. Despite these concerns, we found a very clear bioaccumulation trend in 1999, the only year where comprehensive information on both methylmercury concentrations in water and biota was available.

Bioaccumulation and food chain transfer of corrosion products from radioactive stainless steel

International Nuclear Information System (INIS)

Young, J.S.

1986-07-01

Two sets of experiments were conducted to determine if corrosion products from radioactive Type 347 stainless steel could be biologically transferred from sediment through a marine food chain, and whether corrosion products dissolved in seawater could be bioaccumulated and then eliminated. Corrosion products containing 60 Co and 63 Ni from the radioactive stainless steel were introduced into marine sediments. Infaunal polychaete worms exposed to these sediments bioaccumulated the radionuclides. The feeding of these worms to shrimp and fish resulted in a trophic transfer of the radioactive products across a one-step food chain. The magnitude of the transfers are described in terms of transfer factors. Dissolved corrosion products as measured by the radionuclides were also bioaccumulated by shrimp and fish concentrating more than fish. Concentration factors were calculated

Toxicity and bioaccumulation of chlorophenols in earthworms, in relation to bioavailability in soil

Energy Technology Data Exchange (ETDEWEB)

van Gestel, C.A.; Ma, W.C.

1988-06-01

The acute toxicity of five chlorophenols for two earthworm species was determined in two sandy soils differing in organic matter content and the results were compared with adsorption data. Adsorption increased with increasing organic matter content of the soils, but for tetra- and pentachlorophenol was also influenced by soil pH. Earthworm toxicity was significantly higher in the soil with a low level of organic matter. This difference disappeared when LC50 values were recalculated to concentrations in soil solution using adsorption data. Eisenia fetida andrei showed LC50 values lower than those of Lumbricus rubellus although bioaccumulation was generally higher in the latter species. Toxicity and bioaccumulation based on soil solution concentrations increased with increasing lipophilicity of the chlorophenols. The present results indicate that the toxicity and bioaccumulation and therefore the bioavailability of chlorophenols in soil to earthworms are dependent on the concentration in soil solution and can be predicted on the basis of adsorption data. Both the toxicity of and bioaccumulation data on chlorophenols in earthworms demonstrated surprisingly good agreement with those on chlorophenols in fish.

Determination of PBDEs in human milk. Analysis and quality control

Energy Technology Data Exchange (ETDEWEB)

Paepke, O.; Herrmann, T. [Ergo Research, Hamburg (Germany); Vieth, B.; Ostermann, B. [Federal Institute for Risk Assessment, Berlin (Germany)

2004-09-15

Polybrominated diphenylethers (PBDEs) are widely used as flame retardants in polymer materials, textiles, electronic boards and various other materials. Technical PBDE preparations are produced as mixtures of mainly penta-, octa- or decabromobiphenyl ethers. PBDEs are structurally similar to other environmental pollutants, such as dioxins and PCBs. They are lipophilic and persistent compounds and widespread in the environment. For certain congeners, bioaccumulation has been observed. Recent findings of increasing levels in humans showed that more detailed investigations of human milk (or other suitable matrices) will be required in order to evaluate the general human exposure to this group of environmental contaminants. Only a few data on PBDE levels in breast milk from Germany had been published. To fill the data gaps, in 2001 a controlled study was started to characterize the PBDE levels in human milk from Germany with special efforts to identify and quantify deca-BDE-209. 103 samples were analyzed in this study so far including 10 hidden pool samples provided by Federal Institute for Risk Assessment to ERGO laboratory (total number of samples finally will be 157 (including 14 hidden pool samples)). This paper describes the analytical procedure applied and emphasizes on the quality control procedure.

Brominated flame retardants in birds of prey from Flanders, Belgium

Energy Technology Data Exchange (ETDEWEB)

Voorspoels, S.; Covaci, A.; Schepens, P. [Antwerp Univ., Wilrijk (Belgium). Toxicological Centre

2004-09-15

Since their introduction on the market, environmental levels of polybrominated diphenyl ethers (PBDEs) are continuously increasing. This is caused by spillage and emission during production and use, but also by improper disposal at the end-of-life of the products in which they are used. These chemicals are highly persistent and lipophilic which results in bioaccumulation in fatty tissues of biota and biomagnification throughout the food chain. Because PBDEs have a high toxicological potential, this biomagnification can have serious health consequences for top-predators, such as birds of prey. Data about PBDE concentrations in terrestrial biota, especially in birds of prey, is scarce. A rapid increase of PBDE concentrations has been seen in pooled guillemot (Uria algae) eggs from the Baltic proper7 during the late 1970's and early 1980's, followed by a decrease during the 1990's8. In herring gull eggs from the Great Lakes, the PBDE concentrations increased exponentially from 1981 to 2000. Most of the studies look at concentrations in eggs, while less is known about tissue levels and distribution of these pollutants in birds of prey.

Heavy metal bioaccumulation in Callinectes amnicola and ...

African Journals Online (AJOL)

The bioaccumulation of heavy metals in organisms is as a result of pollutants discharge generated by anthropogenic and natural activities which has become a tremendous concern in developing nations. The levels of cadmium, copper, chromium, lead, zinc and nickel in the tissue of Callinectes amnicola and ...

Bioaccumulation and distribution of organochlorine residues across ...

African Journals Online (AJOL)

Eighteen organochlorine pesticide (OCP) residues were measured in the water, sediment, plankton, benthic invertebrates and fish in various sections of the Lagos Lagoon in 2014 to investigate their bioaccumulation and distribution in the food web. The analysis was done using gas chromatography with an electron capture ...

Enantiomerization and stereoselectivity in bioaccumulation of furalaxyl in Tenebrio molitor larvae.

Science.gov (United States)

Yin, Jing; Gao, Yongxin; Zhu, Feilong; Hao, Weiyu; Xu, Qi; Wang, Huili; Guo, Baoyuan

2017-11-01

Furalaxyl is a chiral pesticide and widely used in modern agriculture as racemate mixture. The enantiomerization and enantioselecive bioaccumulation by a single dose of furalaxyl to Tenebrio molitor larvae under laboratory conditions were studied using a high-performance liquid chromatography tandem mass spectroscopy method based on a ChiralPAK IC column. Our results showed that a significant enantiomerization (interconversion between R-enantiomer and S-enantiomer) was observed in Tenebrio molitor larvae under R- or S-furalaxyl exposure. Though the two furalaxyl enantiomers exhibited low-capacity of bioaccumulation in Tenebrio molitor larvae, bioaccumulation of rac-furalaxyl was enantioselective with a preferential accumulation of S-furalaxyl at 10mg/kg dosage exposure. In addition, enantiomerization and enantioselective degradation of the two enantiomers was not observed in wheat bran. These results showed that enantioselectivtiy of furalaxyl enantiomers was an important process combined with degradation, metabolism and enatiomerization in organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Apparent bioaccumulation of cylindrospermopsin and paralytic shellfish toxins by finfish in Lake Catemaco (Veracruz, Mexico).

Science.gov (United States)

Berry, J P; Jaja-Chimedza, A; Dávalos-Lind, L; Lind, O

2012-01-01

Compared to the well-characterized health threats associated with contamination of fish and shellfish by algal toxins in marine fisheries, the toxicological relevance of the bioaccumulation of toxins from cyanobacteria (blue-green algae), as the primary toxigenic algae in freshwater systems, remains relatively unknown. Lake Catemaco (Veracruz, Mexico) is a small, tropical lake system specifically characterized by a year-round dominance of the known toxigenic cyanobacterial genus, Cylindrospermopsis, and by low, but detectable, levels of both a cyanobacterial hepatotoxin, cylindrospermopsin (CYN), and paralytic shellfish toxins (PSTs). In the present study, we evaluated, using enzyme-linked immunoassay (ELISA), levels of both toxins in several species of finfish caught and consumed locally in the region to investigate the bioaccumulation of, and possible health threats associated with, these toxins as potential foodborne contaminants. ELISA detected levels of both CYN and PSTs in fish tissues from the lake. Levels were generally low (≤ 1 ng g(-1) tissue); however, calculated bioaccumulation factors (BAFs) indicate that toxin levels exceed the rather low levels in the water column and, consequently, indicated bioaccumulation (BAF >1). A reasonable correlation was observed between measured bioaccumulation of CYN and PSTs, possibly indicating a mutual source of both toxins, and most likely cells of Cylindrospermopsis, the dominant cyanobacteria in the lake, and a known producer of both metabolites. The potential roles of trophic transport in the system, as well as possible implications for human health with regards to bioaccumulation, are discussed.

Black Carbon Inclusive Multichemical Modeling of PBDE and PCB Biomagnification and -Transformation in Estuarine Food Webs

NARCIS (Netherlands)

Paolo, C.; Gandhi, N.; Bhavsar, S.; Heuvel-Greve, van den M.J.; Koelmans, A.A.

2010-01-01

Bioavailability and bioaccumulation of polybrominated diphenylethers (PBDEs) are affected by adsorption on black carbon (BC) and metabolism in biota, respectively. Recent studies have addressed these two processes separately, illustrating their importance in assessing contaminant dynamics. In order

Bioaccumulation of hydroxylated polychlorinated biphenyls and pentachlorophenol in the serum of northern elephant seal pups (Mirounga angustirostris)

Energy Technology Data Exchange (ETDEWEB)

Louis, Caroline, E-mail: caroline.louis@uclouvain.be [Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium); Covaci, Adrian [Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Stas, Marie [Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium); Crocker, Daniel E. [Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928 (United States); Malarvannan, Govindan [Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Dirtu, Alin C. [Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Department of Chemistry, “Al. I. Cuza” University of Iasi, 700506 Iasi (Romania); Debier, Cathy [Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium)

2015-01-15

Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were sampled at 1-, 4-, 7- and 10-week post-weaning. Concentrations of hydroxylated polychlorinated biphenyls (HO-PCBs) and their parent PCBs were measured in the serum of each individual. The ΣHO-PCB concentrations in the serum increased significantly between early and late fast (from 282±20 to 529±31 pg/mL). This increase might result from a mobilisation of HO-PCBs transferred from the mother during gestation and/or lactation and stored in the pup's liver. Food deprivation has been shown to exacerbate biotransformation capacities in mammals, birds and fish. The HO-penta-CBs was the predominant homologue group, followed by HO-hexa-CBs and HO-hepta-CBs. No preferential pathway for the metabolism of HO-PCBs (HO-direct insertion or NIH-shift of a chlorine atom) could be evidenced. The concentrations of pentachlorophenol (PCP) in the serum of weaned NES increased from 103±7 pg/mL at early fast to 246±41 pg/mL at late fast, which is within the range of PCP concentrations usually encountered in marine mammals. - Highlights: • Σ HO-PCB concentrations in serum significantly increased between early and late fast. • The HO-penta-CBs were the predominant homologue group measured in serum. • No preferential pathway for the metabolism of HO-PCBs could be evidenced. • PCP concentrations in serum significantly increased between early and late fast.

Bioaccumulation of hydroxylated polychlorinated biphenyls and pentachlorophenol in the serum of northern elephant seal pups (Mirounga angustirostris)

International Nuclear Information System (INIS)

Louis, Caroline; Covaci, Adrian; Stas, Marie; Crocker, Daniel E.; Malarvannan, Govindan; Dirtu, Alin C.; Debier, Cathy

2015-01-01

Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were sampled at 1-, 4-, 7- and 10-week post-weaning. Concentrations of hydroxylated polychlorinated biphenyls (HO-PCBs) and their parent PCBs were measured in the serum of each individual. The ΣHO-PCB concentrations in the serum increased significantly between early and late fast (from 282±20 to 529±31 pg/mL). This increase might result from a mobilisation of HO-PCBs transferred from the mother during gestation and/or lactation and stored in the pup's liver. Food deprivation has been shown to exacerbate biotransformation capacities in mammals, birds and fish. The HO-penta-CBs was the predominant homologue group, followed by HO-hexa-CBs and HO-hepta-CBs. No preferential pathway for the metabolism of HO-PCBs (HO-direct insertion or NIH-shift of a chlorine atom) could be evidenced. The concentrations of pentachlorophenol (PCP) in the serum of weaned NES increased from 103±7 pg/mL at early fast to 246±41 pg/mL at late fast, which is within the range of PCP concentrations usually encountered in marine mammals. - Highlights: • Σ HO-PCB concentrations in serum significantly increased between early and late fast. • The HO-penta-CBs were the predominant homologue group measured in serum. • No preferential pathway for the metabolism of HO-PCBs could be evidenced. • PCP concentrations in serum significantly increased between early and late fast

Role of metal mixtures (Ca, Cu and Pb) on Cd bioaccumulation and phytochelatin production by Chlamydomonas reinhardtii.

Science.gov (United States)

Abboud, Pauline; Wilkinson, Kevin J

2013-08-01

The goal of the study was to determine whether metal uptake and biological effects could be predicted by free ion concentrations when organisms were exposed to Cd and a second metal. Bioaccumulation and algal phytochelatin (PC) concentrations were determined for Chlamydomonas reinhardtii following a 6-h exposure. Bioaccumulation results, after six hours of exposure, showed that Cd uptake decreased in the presence of relatively high concentrations of Ca, Cu and Pb, however, Cd bioaccumulation increased in the presence of ca. equimolar concentrations of Cu. A good correlation was observed between the production of PCs and the amount of metals bioaccumulated for the binary mixtures of Cd-Pb and Cd-Cu, but not the Cd-Ca mixture. Overall, the results suggested that, in the case of mixtures, bioaccumulated metal rather than free ion concentrations would be a better predictor of biological effect. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydroxylated polychlorinated biphenyls increase reactive oxygen species formation and induce cell death in cultured cerebellar granule cells

International Nuclear Information System (INIS)

Dreiem, Anne; Rykken, Sidsel; Lehmler, Hans-Joachim; Robertson, Larry W.; Fonnum, Frode

2009-01-01

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in the body, however, they can be metabolized to more water-soluble products. Although they are more readily excreted than the parent compounds, some of the metabolites are still hydrophobic and may be more available to target tissues, such as the brain. They can also cross the placenta and reach a developing foetus. Much less is known about the toxicity of PCB metabolites than about the parent compounds. In the present study, we have investigated the effects of eight hydroxylated (OH) PCB congeners (2'-OH PCB 3, 4-OH PCB 14, 4-OH PCB 34, 4'-OH PCB 35, 4-OH PCB 36, 4'-OH PCB 36, 4-OH PCB 39, and 4'-OH PCB 68) on reactive oxygen species (ROS) formation and cell viability in rat cerebellar granule cells. We found that, similar to their parent compounds, OH-PCBs are potent ROS inducers with potency 4-OH PCB 14 < 4-OH PCB 36 < 4-OH PCB 34 < 4'-OH PCB 36 < 4'-OH PCB 68 < 4-OH PCB 39 < 4'-OH PCB 35. 4-OH PCB 36 was the most potent cell death inducer, and caused apoptotic or necrotic morphology depending on concentration. Inhibition of ERK1/2 kinase with U0126 reduced both cell death and ROS formation, suggesting that ERK1/2 activation is involved in OH-PCB toxicity. The results indicate that the hydroxylation of PCBs may not constitute a detoxification reaction. Since OH-PCBs like their parent compounds are retained in the body and may be more widely distributed to sensitive tissues, it is important that not only the levels of the parent compounds but also the levels of their metabolites are taken into account during risk assessment of PCBs and related compounds.

Biochemical basis of mercury remediation and bioaccumulation by Enterobacter sp. EMB21.

Science.gov (United States)

Sinha, Arvind; Kumar, Sumit; Khare, Sunil Kumar

2013-01-01

The aims of this study were to isolate metal bioaccumulating bacterial strains and to study their applications in removal of environmental problematic heavy metals like mercury. Five bacterial strains belonging to genera Enterobacter, Bacillus, and Pseudomonas were isolated from oil-spilled soil. Among these, one of the strains Enterobacter sp. EMB21 showed mercury bioaccumulation inside the cells simultaneous to its bioremediation. The bioaccumulation of remediated mercury was confirmed by transmission electron microscopy and energy dispersive X-ray. The mercury-resistant loci in the Enterobacter sp. EMB21 cells were plasmid-mediated as confirmed by transformation of mercury-sensitive Escherichia coli DH5α by Enterobacter sp. EMB21 plasmid. Effect of different culture parameters viz-a-viz inoculum size, pH, carbon, and nitrogen source revealed that alkaline pH and presence of dextrose and yeast extract favored better remediation. The results indicated the usefulness of Enterobacter sp. EMB21 for the effective remediation of mercury in bioaccumulated form. The Enterobacter sp. EMB21 seems promising for heavy metal remediation wherein the remediated metal can be trapped inside the cells. The process can further be developed for the synthesis of valuable high-end functional alloy, nanoparticles, or metal conjugates from the metal being remediated.

Intracrystalline fractionation of oxygen isotopes between hydroxyl and non-hydroxyl sites in kaolinite measured by thermal dehydroxylation and partial fluorination

Science.gov (United States)

Girard, Jean-Pierre; Savin, Samuel M.

1996-02-01

Thermal dehydroxylation and partial fluorination techniques were used to measure intracrystalline fractionation of oxygen isotopes between hydroxyl and non-hydroxyl sites in kaolinite. Several aliquots of a well characterized, fine-grained (rates, and target temperatures. Measured δ18O values of both the liberated water and the dehydroxylated residue are consistent over a wide range of temperatures (550 850°C) when dehydroxylation is performed in a single-step fashion at a rapid heating rate (>50°C/min.). Similar dehydroxylation experiments indicate that brucite dehydroxylation occurs without any significant isotopic fractionation of the oxygen isotopes. By extrapolation we postulate that no significant fractionation occurs during single-step thermal dehydroxylation of fine-grained kaolinite, provided that dehydroxylation is performed under well controlled conditions. In contrast, gibbsite dehydroxylation is accompanied by substantial isotopic fractionation. This is probably the result of the complex, multi-pathway dehydroxylation reaction of this mineral. Similarly, thermal dehydroxylation of coarsegrained (>1 μm) kaolinites and dickites of weathering and hydrothermal origin yield results that are dependent on the temperature of dehydroxylation. We suggest that this effect may be caused by isotopic exchange during diffusion of water molecules through coarse particles. Partial fluorination of fine-grained kaolinite in the presence of excess F2 at low temperatures (rate of reaction of hydroxyl oxygen than of non-hydroxyl oxygen, but examination of the isotopic data as well as XRD and IR analyses of the residues after partial fluorination indicates that the separation between the two types of oxygen is not complete. The results, therefore, do not yield a reliable δ18O value of the hydroxyl oxygen. The results of this study suggest that the thermal dehydroxylation technique may be appropriate for analysis of OH groups in fine-grained kaolinite. The partial

Medium-chain chlorinated paraffins (MCCPs): a review of bioaccumulation potential in the aquatic environment.

Science.gov (United States)

Thompson, Roy; Vaughan, Martin

2014-01-01

Chlorinated paraffins (CPs) are high molecular weight organochlorine compounds that have been used in a variety of industrial applications for many years. Medium-chain chlorinated paraffins (MCCPs) (CAS 85535-85-9; Alkanes, C14-17 , chloro) are currently under investigation as potential persistent bioaccumulative toxic (PBT) compounds. In this article, the bioaccumulation potential of MCCPs is assessed using a tiered framework proposed after a recent Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop in 2008. The framework proposes the use of physicochemical properties and modeling assessment, bioconcentration/bioaccumulation (BCF/BAF) assessment, biomagnification (BMF) assessment, and trophic magnification factor (TMF) assessment. It is hoped that use of this framework could harmonize and improve the efficiency and effectiveness of the chemical substance evaluation screening process for PBT properties. When applied to MCCPs, the following conclusions were made: empirical physiochemical data is available negating the use of models; laboratory BCFs range from 1000 to 15 000 (growth-corrected lipid normalized values) for 2 MCCP structures; field BAFs were an order of magnitude higher than the trigger criterion for "B status possible"; although results may not meet acceptance criteria for field studies, laboratory-derived BMFs for a number of C14-17 chlorinated alkanes were less than the trigger value of 1 (based on whole-body concentrations) whereas field-derived BMFs were less than 1 (based on lipid corrected values [generally used for field data] excluding one measure for sculpin, [Cottus cognatus]-Diporeia that was based on only one detectable sample); and finally, TMFs were less than the trigger criterion value of 1, which are considered the most convincing evidence for bioaccumulative properties of a compound and the "Gold Standard" measure of bioaccumulation. This article also discusses the uncertainties surrounding the published data

Review of laboratory-based terrestrial bioaccumulation assessment approaches for organic chemicals: Current status and future possibilities.

Science.gov (United States)

Hoke, Robert; Huggett, Duane; Brasfield, Sandra; Brown, Becky; Embry, Michelle; Fairbrother, Anne; Kivi, Michelle; Paumen, Miriam Leon; Prosser, Ryan; Salvito, Dan; Scroggins, Rick

2016-01-01

In the last decade, interest has been renewed in approaches for the assessment of the bioaccumulation potential of chemicals, principally driven by the need to evaluate large numbers of chemicals as part of new chemical legislation, while reducing vertebrate test organism use called for in animal welfare legislation. This renewed interest has inspired research activities and advances in bioaccumulation science for neutral organic chemicals in aquatic environments. In January 2013, ILSI Health and Environmental Sciences Institute convened experts to identify the state of the science and existing shortcomings in terrestrial bioaccumulation assessment of neutral organic chemicals. Potential modifications to existing laboratory methods were identified, including areas in which new laboratory approaches or test methods could be developed to address terrestrial bioaccumulation. The utility of "non-ecotoxicity" data (e.g., mammalian laboratory data) was also discussed. The highlights of the workshop discussions are presented along with potential modifications in laboratory approaches and new test guidelines that could be used for assessing the bioaccumulation of chemicals in terrestrial organisms. © 2015 SETAC.

Bioaccumulation factor of {sup 137}Cs in some marine biotas from West Bangka Indonesia

Energy Technology Data Exchange (ETDEWEB)

Suseno, Heny, E-mail: henis@batan.go.id [Radioactive Waste Technology Center - The Indonesia Nuclear Energy Agency (BATAN) (Indonesia)

2014-03-24

Radionuclides may be released from nuclear facilities to the marine environment. Concentrations of radionuclides within marine biotic systems can be influenced by a number of factors, including the type of biota, its source, the radionuclide, and specific characteristics of the sampled specimens and the marine environment (salinity, etc.). The bioconcentration factor for a marine organism is the ratio of the concentration of a radionuclide in that organism to the concentration found in its marine water environment - under conditions of equilibrium. Information on the bioaccumulation of Cs-137 in marine organisms is required to risk assessment evaluates the potential risks to human health. Bioaccumulation of Cs was investigated in marine biota from west Bangka such as Marine cat fish (Arius thalassinus), Baramundi (Lates calcarifer), Mackerel (Scomberomorus commerson), Striped eel catfish (Plotosus lineatus), eel tailed fish (Euristhmus microceps), Yellowtail fusilier (Caesio erythrogaster), Coastal crab (Scylla sp), White shrimp (Penaeus merguiensis) and marine bivalve mollusk (Anadara granosa). Muscle of these marine biota, sediments and water were assayed for Cs-137 by HPGe gamma spectrometer. The bioaccumulation factor for fishes were calculated by ratio of concentration Cs-137 in muscle biota to the its concentration in water. The bioaccumulation factor for mollusks were calculates by ratio of concentration Cs-137 in muscle biota to the its concentration in sediments. The bioaccumulation factor were range 4.99 to 136.34.

Organochlorine pollution in tropical rivers (Guadeloupe): Role of ecological factors in food web bioaccumulation

Energy Technology Data Exchange (ETDEWEB)

Coat, Sophie, E-mail: coatsophie@gmail.com [EA 926 DYNECAR, Laboratoire de Biologie Marine, UFR Sciences, Universite des Antilles et de la Guyane, BP592, 97159 Pointe-a-Pitre Cedex (France); Monti, Dominique, E-mail: dominique.monti@univ-ag.fr [EA 926 DYNECAR, Laboratoire de Biologie Marine, UFR Sciences, Universite des Antilles et de la Guyane, BP592, 97159 Pointe-a-Pitre Cedex (France); Legendre, Pierre, E-mail: pierre.legendre@umontreal.ca [Departement de Sciences Biologique, Universite de Montreal, C.P. 6128, succursale A, Montreal, Quebec H3C 3J7 (Canada); Bouchon, Claude, E-mail: claude.bouchon@univ-ag.fr [EA 926 DYNECAR, Laboratoire de Biologie Marine, UFR Sciences, Universite des Antilles et de la Guyane, BP592, 97159 Pointe-a-Pitre Cedex (France); Massat, Felix, E-mail: fmassat@ladrome.fr [LDA26, laboratoire Departemental d' Analyses de la Drome, 27 avenue Lautagne, 26000 Valence (France); Lepoint, Gilles, E-mail: g.lepoint@ulg.ac.be [MARE Centre, Laboratoire d' Oceanologie, Universite de Liege, Bat. B6, 4000 Sart Tilman, Belgique (Belgium)

2011-06-15

Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon were measured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examine the bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a general and heavy contamination of the entire food web. They revealed the strong accumulation of pollutants by juveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in the bioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone and monohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of {beta}-HCH was only influenced by animal lipid content. The biomagnification potential of chlordecone through the food chain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulation process. In contrast, bioconcentration by passive diffusion from water seemed to be the main exposure route of biota to {beta}-HCH. - Highlights: > We measured OC pesticides and stable isotope ratios in a tropical stream. > Results showed a strong and ubiquitous contamination of the entire food web. > Diadromous juveniles strongly accumulated pollutants when they re-enter the river. > The most persistent pollutant (chlordecone) was related to species diet and habitat. > {beta}-HCH was only influenced by animal lipid content. - This paper determines the bioaccumulation and transfer processes of organochlorine pesticides within the stream food web in Guadeloupe (Caribbean).

Self-hydroxylation of the splicing factor lysyl hydroxylase, JMJD6

DEFF Research Database (Denmark)

Mantri, M.; Webby, C.J.; Loik, N.D.

2012-01-01

The lysyl 5S-hydroxylase, JMJD6 acts on proteins involved in RNA splicing. We find that in the absence of substrate JMJD6 catalyses turnover of 2OG to succinate. H-NMR analyses demonstrate that consumption of 2OG is coupled to succinate formation. MS analyses reveal that JMJD6 undergoes self......-hydroxylation in the presence of Fe(ii) and 2OG resulting in production of 5S-hydroxylysine residues. JMJD6 in human cells is also found to be hydroxylated. Self-hydroxylation of JMJD6 may play a regulatory role in modulating the hydroxylation status of proteins involved in RNA splicing. This journal is...

Stereoselectivity in bioaccumulation and excretion of epoxiconazole by mealworm beetle (Tenebrio molitor) larvae.

Science.gov (United States)

Lv, Xiaotian; Liu, Chen; Li, Yaobin; Gao, Yongxin; Wang, Huili; Li, Jianzhong; Guo, Baoyuan

2014-09-01

Stereoselectivity in bioaccumulation and excretion of stereoisomers of epoxiconazole by mealworm beetle (Tenebrio molitor) larvae through dietary exposure was investigated. Liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method that use a ChiralcelOD-3R[cellulosetris-Tris-(3, 5-dichlorophenyl-carbamate)] chromatography column was applied to carry out chiral separation of the stereoisomers. Wheat bran was spiked with racemic epoxiconazole at two dose levels of 20mg/kg and 2mg/kg (dry weight) to feed T. molitor larvae. The results showed that both the doses of epoxiconazole were taken up by Tenebrio molitor larvae rapidly at the initial stages. There was a significant trend of stereoselective bioaccumulation in the larvae with a preferential accumulation of (-)-epoxiconazole in the 20mg/kg dose. The stereoselectivity in bioaccumulation in the 2mg/kg dosage was not obvious compared to the 20mg/kg group. Results of excretion indicated an active excretion is an important pathway for the larvae to eliminate epoxiconazole which was a passive transport process with non stereoselectivity. The faster elimination might be the reason for the low accumulation of epoxiconazole, as measured by bioaccumulation factor (BAF). Copyright © 2014 Elsevier Inc. All rights reserved.

Bioaccumulation of radiocesium by fish: the influence of physicochemical factors and trophic structure

International Nuclear Information System (INIS)

Rowan, D.J.; Rasmussen, J.B.

1994-01-01

Although many measurements have been made on radiocesium levels in water and aquatic biota, no agreement has been reached regarding the factors affecting bioaccumulation of these radionuclides. With monitoring data from countries that operate nuclear facilities and data from the primary literature, we explored the chemical and ecological factors that determine the bioaccumulation of radiocesium. Using log-linear regression we found that the bioaccumulation of 137 CS by fish was a negative function of both dissolved potassium and suspended sediment concentration, and a positive function of temperature. Important ecological factors were the trophic level of the fish (piscivores bioaccumulate more than planktivores and benthivores), and the length of the food chain as reflected by the ratio of piscivore yield relative to net primary production. Fish from softwater drainages, which make up a large portion of northern Europe and Canada, are more vulnerable to radiocesium contamination than fish from hardwater sedimentary drainages, because these waters are extremely low in potassium and suspended sediment, and their watersheds are less efficient in retaining radiocesium. High dissolved potassium, short food chains, and the much greater volume and mixing potential of the ocean make marine fish less vulnerable to releases of radiocesium. (author)

Bioaccumulation of 137Cs and 60Co by Helianthus annuus

International Nuclear Information System (INIS)

Hornik, M.; Pipiska, M.; Vrtoch, L.; Augustin, J.; Lesny, J.

2005-01-01

The 60 Co and 137 Cs bioaccumulation by Helianthus annuus L. was measured during 9 day cultivation at 20 ± 2 o C in hydroponic Hoagland medium. Previous starvation for K + and for NH 4 + 2.2 and 2.7 times, respectively, enhanced 137 Cs uptake rate. Previous cultivation in surplus of K + ions 50 mmol·l -1 has no effect on 137 Cs bioaccumulation rate. Both 137 Cs and 60 Co bioaccumulation significantly increase with dilution of basic Hoagland medium up to 1:7 for caesium and up to 1:3 for cobalt followed by mild decrease at higher dilutions. Root to shoot specific 137 Cs radioactivity ratio (Bq.g -1 /Bq·g -1 , fresh wt.) increased with dilution from 1.46 to 9.6-9.8. The values root to shoot specific radioactivity ratio for 60 Co were less dependent on the nutrient concentrations and were within the range 5.7 to 8.5. 137 Cs was localized mainly in young leaves (30%) and roots (39%) and 60 Co mainly in roots (67%) and leaves (20%). Obtained data showed less sensitivity of 60 Co uptake by sunflower on nutrient concentration in hydroponic media. (author)

Bioaccumulation of microcystins in two freshwater gastropods from a cyanobacteria-bloom plateau lake, Lake Dianchi

International Nuclear Information System (INIS)

Zhang Junqian; Wang Zhi; Song Zhuoyan; Xie Zhicai; Li Lin; Song, Lirong

2012-01-01

To investigate the bioaccumulation patterns of microcystins (MCs) in organs of two gastropods, samples were collected in Lake Dianchi monthly from May to October, 2008, when cyanobacteria typically bloom. The average MCs concentrations for Radix swinhoei (pulmonate) and Margarya melanioides (prosobranch) tended to be similar for the different organs: the highest values in the hepatopancreas (9.33 by 3.74 μg/g DW), followed by digestive tracts (1.66 by 3.03 μg/g DW), gonads (0.45 by 1.34 μg/g DW) and muscles (0.22 by 0.40 μg/g DW). Pulmonate had higher value than prosobranch because of the stronger bioaccumulation ability in hepatopancreas. The levels in organs of R. swinhoei were correlated with environmentally dissolved MCs, but influenced by intracellular MCs for M. melanioides. The estimated MCs concentrations in edible parts of M. melanioides were beyond the WHO’s provisional tolerable daily intake (0.04 μg/kg), suggesting the risk of consumption of M. melanioides from the lake. Highlights: ► We probe bioaccumulated patterns of microcystins in organs of pulmonate and prosobranch. ► The highest microcystins in hepatopancreas for both snails. ► The higher microcystins for pulmonate results from the stronger bioaccumulation ability in hepatopancreas. ► Environmentally dissolved microcystins are the main sources for pulmonate, but intracellular for prosobranch. ► Suggesting the risk of consumption snails in the studying regions. - Higher bioaccumulation MCs level for pulmonate mainly contributed to the stronger bioaccumulation ability in its hepatopancreas.

Polybrominated diphenyl ether flame retardants in Virginia freshwater fishes (USA).

Science.gov (United States)

Hale, R C; La Guardia, M J; Harvey, E P; Mainor, T M; Duff, W H; Gaylor, M O

2001-12-01

Polybrominated diphenyl ethers (PBDEs) were examined in fish fillets collected from two large Virginia watersheds. Emphasis was on the tetra- to hexabrominated congeners since these exhibit the greatest bioaccumulation and toxicological potentials. These congeners are dominant constituents of Penta-, a commercial PBDE product used to flame retard polyurethane foam. In 1999, North America accounted for98% of global Penta-demand. Concentrations of total tetra- to hexabrominated congeners in fillets ranged from furniture and textile manufacturing, although polyurethane foam production here has been limited.

BIOACCUMULATION AND DEPURATION STUDIES OF LEAD NITRATE ON ECONOMICALLY IMPORTANT SHRIMP PENAEOUS MONODON

OpenAIRE

S.Palani Kumar; A.S.Sharadhamma

2013-01-01

Current study of Bioaccumulation and Depuration of Lead nitrate on marine shrimp Penaeous monodon shows Lead nitrate accumulation more in hepatopancreas compared to muscle and the depuration level of heavy metal Lead nitrate was more through hepatopancreas comparing to muscle tissues, when comparing to the control animals.This shows the major role of Hepatopacreas in Bioaccumulation and depuration in this study on muscle tissues and hepatopancreas tissues

Regioselective alkane hydroxylation with a mutant AlkB enzyme

Science.gov (United States)

Koch, Daniel J.; Arnold, Frances H.

2012-11-13

AlkB from Pseudomonas putida was engineered using in-vivo directed evolution to hydroxylate small chain alkanes. Mutant AlkB-BMO1 hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. Mutant AlkB-BMO2 similarly hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. These biocatalysts are highly active for small chain alkane substrates and their regioselectivity is retained in whole-cell biotransformations.

Hydroxylation of the herbicide isoproturon by fungi isolated from agricultural soil.

Science.gov (United States)

Rønhede, Stig; Jensen, Bo; Rosendahl, Søren; Kragelund, Birthe B; Juhler, René K; Aamand, Jens

2005-12-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N-(4-isopropylphenyl)-N'-methylurea. In soils, however, hydroxylated metabolites have also been detected. In this study we identified fungi as organisms that potentially play a major role in the formation of these hydroxylated metabolites in soils treated with isoproturon. Isolates of Mortierella sp. strain Gr4, Phoma cf. eupyrena Gr61, and Alternaria sp. strain Gr174 hydroxylated isoproturon at the first position of the isopropyl side chain, yielding N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea, while Mucor sp. strain Gr22 hydroxylated the molecule at the second position, yielding N-(4-(1-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea. Hydroxylation was the dominant mode of isoproturon transformation in these fungi, although some cultures also produced traces of the N-demethylated metabolite N-(4-isopropylphenyl)-N'-methylurea. A basidiomycete isolate produced a mixture of the two hydroxylated and N-demethylated metabolites at low concentrations. Clonostachys sp. strain Gr141 and putative Tetracladium sp. strain Gr57 did not hydroxylate isoproturon but N demethylated the compound to a minor extent. Mortierella sp. strain Gr4 also produced N-(4-(2-hydroxy-1-methylethyl)phenyl)-N'-methylurea, which is the product resulting from combined N demethylation and hydroxylation.

Effects of polybrominated diphenyl ethers (PBDEs) and their derivatives on protein disulfide isomerase activity and growth hormone release of GH3 cells.

Science.gov (United States)

Hashimoto, Shoko; Yoshimura, Hiromi; Okada, Kazushi; Uramaru, Naoto; Sugihara, Kazumi; Kitamura, Shigeyuki; Imaoka, Susumu

2012-03-19

Polybrominated diphenyl ethers (PBDEs) have been used in a variety of consumer products such as flame retardants and recently have been known to be widespread environmental pollutants, which probably affect biological functions of mammalian cells. However, the risk posed by PBDE metabolites has not been clarified. Our previous study suggested that bisphenol A (BPA), an endocrine-disrupting chemical, binds to protein disulfide isomerase (PDI) and inhibits its activity. PDI is an isomerase enzyme in the endoplasmic reticulum and facilitates the formation or cleavage of disulfide bonds. PDI consists of a, b, b', and a' domains and the c region, with the a and a' domains having isomerase active sites. In the present study, we tested the effects of 10 kinds of PBDE compounds and their metabolites on PDI. OH-PBDEs specifically inhibited the isomerase activity of PDI, with 4'-OH-PBDE more effective than 2' (or 2)-OH-PBDEs. 4'-OH-PBDE inhibited the isomerase activity of the b'a'c fragment but not that of ab and a'c, suggesting that the b' domain of PDI is essential for the inhibition by 4'-OH-PBDE. We also investigated the effects of these chemicals on the production of growth hormone (GH) in GH3 cells. In GH3 cells, levels of mRNA and protein of GH stimulated by T(3) were reduced by 4'-OH-PBDE and 4'-MeO-PBDE. The reduction in GH expression caused by these compounds was not changed by the overexpression or knockdown of PDI in GH3 cells, while these manipulations of PDI levels significantly suppressed the expression of GH. These results suggest that the biological effects of PBDEs differed depending on their brominated and hydroxylated positions. © 2011 American Chemical Society

Bioaccumulation dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bioaccumulation dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides was examined in young-of-the-year bluefish from seven sub-estuaries of New...

Nanoparticle interactions with co-existing contaminants: joint toxicity, bioaccumulation and risk.

Science.gov (United States)

Deng, Rui; Lin, Daohui; Zhu, Lizhong; Majumdar, Sanghamitra; White, Jason C; Gardea-Torresdey, Jorge L; Xing, Baoshan

2017-06-01

With their growing production and application, engineered nanoparticles (NPs) are increasingly discharged into the environment. The released NPs can potentially interact with pre-existing contaminants, leading to biological effects (bioaccumulation and/or toxicity) that are poorly understood. Most studies on NPs focus on single analyte exposure; the existing literature on joint toxicity of NPs and co-existing contaminants is rather limited but beginning to develop rapidly. This is the first review paper evaluating the current state of knowledge regarding the joint effects of NPs and co-contaminants. Here, we review: (1) methods for investigating and evaluating joint effects of NPs and co-contaminants; (2) simultaneous toxicities from NPs co-exposed with organic contaminants, metal/metalloid ions, dissolved organic matter (DOM), inorganic ligands and additional NPs; and (3) the influence of NPs co-exposure on the bioaccumulation of organic contaminants and heavy metal ions, as well as the influence of contaminants on NPs bioaccumulation. In addition, future research needs are discussed so as to better understand risk associated with NPs-contaminant co-exposure.

Modeling the role of microplastics in Bioaccumulation of organic chemicals to marine aquatic organisms. Critical Review

NARCIS (Netherlands)

Koelmans, A.A.

2015-01-01

It has been shown that ingestion of microplastics may increase bioaccumulation of organic chemicals by aquatic organisms. This paper critically reviews the literature on the effects of plastic ingestion on the bioaccumulation of organic chemicals, emphasizing quantitative approaches and mechanistic

Hydroxyl radical induced degradation of ibuprofen

Energy Technology Data Exchange (ETDEWEB)

Illés, Erzsébet, E-mail: erzsebet.illes@chem.u-szeged.hu [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary); Takács, Erzsébet [Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary); Dombi, András [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Gajda-Schrantz, Krisztina [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged (Hungary); EMPA, Laboratory for High Performance Ceramics, Duebendorf (Switzerland); Rácz, Gergely; Gonter, Katalin; Wojnárovits, László [Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary)

2013-03-01

Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1 mmol dm{sup −3}. For end product characterization {sup 60}Co γ-irradiation was used and the samples were evaluated either by taking their UV–vis spectra or by HPLC with UV or MS detection. The reactions of {sup ·}OH resulted in hydroxycyclohexadienyl type radical intermediates. The intermediates produced in further reactions hydroxylated the derivatives of ibuprofen as final products. The hydrated electron attacked the carboxyl group. Ibuprofen degradation is more efficient under oxidative conditions than under reductive conditions. The ecotoxicity of the solution was monitored by Daphnia magna standard microbiotest and Vibrio fischeri luminescent bacteria test. The toxic effect of the aerated ibuprofen solution first increased upon irradiation indicating a higher toxicity of the first degradation products, then decreased with increasing absorbed dose. Highlights: ► In hydroxyl radical attack on the ring mainly hydroxylated products form ► The hydrated electron attacks the carboxyl group. ► Oxidative conditions are more effective in ibuprofen decomposition than reductive. ► Ecotoxicity of ibuprofen solution first increases then decreases with irradiation.

Hydroxyl radical induced degradation of ibuprofen

International Nuclear Information System (INIS)

Illés, Erzsébet; Takács, Erzsébet; Dombi, András; Gajda-Schrantz, Krisztina; Rácz, Gergely; Gonter, Katalin; Wojnárovits, László

2013-01-01

Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1 mmol dm −3 . For end product characterization 60 Co γ-irradiation was used and the samples were evaluated either by taking their UV–vis spectra or by HPLC with UV or MS detection. The reactions of · OH resulted in hydroxycyclohexadienyl type radical intermediates. The intermediates produced in further reactions hydroxylated the derivatives of ibuprofen as final products. The hydrated electron attacked the carboxyl group. Ibuprofen degradation is more efficient under oxidative conditions than under reductive conditions. The ecotoxicity of the solution was monitored by Daphnia magna standard microbiotest and Vibrio fischeri luminescent bacteria test. The toxic effect of the aerated ibuprofen solution first increased upon irradiation indicating a higher toxicity of the first degradation products, then decreased with increasing absorbed dose. Highlights: ► In hydroxyl radical attack on the ring mainly hydroxylated products form ► The hydrated electron attacks the carboxyl group. ► Oxidative conditions are more effective in ibuprofen decomposition than reductive. ► Ecotoxicity of ibuprofen solution first increases then decreases with irradiation

Contrasting PCB bioaccumulation patterns among Lake Huron lake trout reflect basin-specific ecology.

Science.gov (United States)

Paterson, Gordon; Ryder, Mark; Drouillard, Ken G; Haffner, G Douglas

2016-01-01

This study collected multiple age classes of lake trout from Lake Huron's Main Basin, Georgian Bay, and North Channel regions to compare and contrast top predator polychlorinated biphenyl (PCB) bioaccumulation patterns in separate compartments of the same ecosystem. Sum PCB concentrations were highest for Main Basin (260 ± 24.9 ng g(-1) wet wt) fish, followed by Georgian Bay (74.6 ± 16.2 ng g(-1) ) and North Channel (42.0 ± 3.3 ng g(-1)) fish. Discriminant functions analysis of lake trout PCB profiles and stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope values clearly distinguished fish by location, indicating high degrees of basin fidelity throughout their lifetimes in addition to highly contrasting PCB bioaccumulation profiles. These unique profiles were not attributable to significant differences in lake trout lipid contents (p = 0.856) or trophic position (δ(15)N; p = 0.334), with rainbow smelt representing the primary prey across the basins. Furthermore, significant differences were observed among the basins for the relationships between PCB biomagnification factors and hydrophobicity. An empirical model for predicting PCB biomagnification in Lake Huron lake trout indicated that basin-specific population growth rates and prey abundances were significant for explaining these contrasting patterns of PCB bioaccumulation. The results of the present study are fundamental for understanding the role of ecology in legacy persistent organic pollutant (POP) bioaccumulation. Specifically, ecosystem characteristics such as prey abundances, foraging ecology, and ultimately consumer growth can regulate the variability of legacy POP bioaccumulation as observed within and among a wide range of freshwater ecosystems. © 2015 SETAC.

Bioaccumulation of heavy metals in two wet retention ponds

DEFF Research Database (Denmark)

Søberg, Laila C.; Vollertsen, Jes; Blecken, Godecke-Tobias

2016-01-01

Metal accumulation in stormwater ponds may contaminate the inhabiting fauna, thus jeopardizing their ecosystem servicing function. We evaluated bioaccumulation of metals in natural fauna and caged mussel indicator organisms in two wet retention ponds. Mussel cages were distributed throughout...... the ponds to detect bioaccumulation gradients and obtain a time-integrated measure of metal bioavailability. We further investigated if sediment metal concentrations correlate with those in the fauna and mussels. Metal concentrations in the fauna tended to be higher in the ponds than in a reference lake......, but statistical significance was only shown for Cu. Positive correlations were found for some metals in fauna and sediment. Sediment metal concentrations in one pond decreased from inlet to outlet while no gradients were observed in the mussels in either pond. These findings indicate that metal accumulation...

Infrared absorption characteristics of hydroxyl groups in coal tars

Energy Technology Data Exchange (ETDEWEB)

Cannon, S A; Chu, C J; Hange, R H; Margrave, J L

1987-01-01

Tar evolution was observed over a temperature range of 150-600 C for four coals. Pittsburgh bituminous, Illinois No.6, Rawhide subbituminous, and Texas lignite. Isolation of the evolved tars in a nitrogen matrix at 15 degrees K produced better resolved infrared spectra than those in a coal matrix, thus enhancing structural characterization of the tar molecules. Two distinct hydroxyl functional groups in the tar molecules free of hydrogen bonding were identified for the first time without interference from H/sub 2/O absorptions. These absorptions at 3626.5 cm/sup -1/ have been assigned to phenolic hydroxyls. It is suggested that carboxylic and aliphatic hydroxyl groups do not survive the vaporization process. Tars from Illinois No.6 were found to contain the largest amount of phenolic hydroxyl; Pittsburgh No. 8 tar contains approximately half of that for Illinois No.6 while Rawhide and Texas lignite contain much less phenolic than either of the other coals. 10 references, 6 figures, 1 table.

Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

Directory of Open Access Journals (Sweden)

Cohn Corey A

2008-02-01

Full Text Available Abstract Background Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF, amplex ultrared, and dichlorofluorescein (DCFH] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles. Results APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity. Conclusion The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.

Influence of salinity on uptake rate and bioaccumulation of /sup 137/Cs in the oyster crassostrea glomerata

International Nuclear Information System (INIS)

Mashiatullah, A.; Qureshi, R.M.; Khan, S.; Chaghtai, F.; Akhter, P.; Jabbar, A.

2008-01-01

This paper describes results of experiment on bioaccumulation and uptake rate of radiocesium /sup 137/Cs from dissolved phase in the flesh of the Oysters (Crassostrea glomerata) collected off Karachi coast. A radiotracer experiment was conducted under laboratory conditions to determine the uptake rate and bioaccumulation of /sup 137/Cs from dissolved phase in the flesh of the Oyster. Oysters (size: 6-7 cm) were subjected to radiocesium activity of 24 Kilobecquerel per liter (kBq L/sup -1/) under three salinity Ievels (25, 30 and 35 ppt). The uptake of /sup 137/Cs was monitored for a period of seven days. The results showed that bioaccumulation and uptake of /sup 137/Cs in oysters were considerably dependent of salinity levels. Higher bioaccumulation factors and uptake rates were found at low salinity levels. (author)

Zinc bioaccumulation in a terrestrial invertebrate fed a diet treated with particulate ZnO or ZnCl2 solution.

Science.gov (United States)

Pipan-Tkalec, Ziva; Drobne, Damjana; Jemec, Anita; Romih, Tea; Zidar, Primoz; Bele, Marjan

2010-03-10

A number of reports on potential toxicity of nanoparticles are available, but there is still a lack of knowledge concerning bioaccumulation. The aim of this work was to investigate how different sources of zinc, such as uncoated and unmodified ZnO nanoparticles, ZnCl(2) in solution, and macropowder ZnO influence the bioaccumulation of this metal in the terrestrial isopod Porcellio scaber. After exposure to different sources of Zn in the diet, the amount of assimilated Zn in whole body, the efficiency of zinc assimilation, and bioaccumulation factors (BAFs) were assessed. The bioaccumulation potential of Zn was found to be the same regardless of Zn source. The amount of assimilated Zn and BAF were dose-dependent, and Zn assimilation efficiency was independent of exposure concentrations. The Zn assimilation capacity was found to be up to 16% of ingested Zn. It is known that as much as approximately 20% of Zn can be accreted from ZnO particles by dissolution. We conclude that bioaccumulation of Zn in isopods exposed to particulate ZnO depends most probably on Zn dissolution from ZnO particles and not on bioaccumulation of particulate ZnO.

Habitat-specific bioaccumulation of methylmercury in invertebrates of small mid-latitude lakes in North America

Energy Technology Data Exchange (ETDEWEB)

Chetelat, John, E-mail: john.chetelat@ec.gc.c [Groupe de recherche interuniversitaire en limnologie, Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7 (Canada); Amyot, Marc; Garcia, Edenise [Groupe de recherche interuniversitaire en limnologie, Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec H3C 3J7 (Canada)

2011-01-15

We examined habitat-specific bioaccumulation of methylmercury (MeHg) in aquatic food webs by comparing concentrations in pelagic zooplankton to those in littoral macroinvertebrates from 52 mid-latitude lakes in North America. Invertebrate MeHg concentrations were primarily correlated with water pH, and after controlling for this influence, pelagic zooplankton had significantly higher MeHg concentrations than littoral primary consumers but lower MeHg than littoral secondary consumers. Littoral primary consumers and pelagic zooplankton are two dominant prey for fish, and greater MeHg in zooplankton is likely sufficient to increase bioaccumulation in pelagic feeders. Intensive sampling of 8 lakes indicated that habitat-specific bioaccumulation in invertebrates (of similar trophic level) may result from spatial variation in aqueous MeHg concentration or from more efficient uptake of aqueous MeHg into the pelagic food web. Our findings demonstrate that littoral-pelagic differences in MeHg bioaccumulation are widespread in small mid-latitude lakes. - Methylmercury levels in dominant invertebrate prey for fish differ between littoral and pelagic habitats within a lake.

Habitat-specific bioaccumulation of methylmercury in invertebrates of small mid-latitude lakes in North America

International Nuclear Information System (INIS)

Chetelat, John; Amyot, Marc; Garcia, Edenise

2011-01-01

We examined habitat-specific bioaccumulation of methylmercury (MeHg) in aquatic food webs by comparing concentrations in pelagic zooplankton to those in littoral macroinvertebrates from 52 mid-latitude lakes in North America. Invertebrate MeHg concentrations were primarily correlated with water pH, and after controlling for this influence, pelagic zooplankton had significantly higher MeHg concentrations than littoral primary consumers but lower MeHg than littoral secondary consumers. Littoral primary consumers and pelagic zooplankton are two dominant prey for fish, and greater MeHg in zooplankton is likely sufficient to increase bioaccumulation in pelagic feeders. Intensive sampling of 8 lakes indicated that habitat-specific bioaccumulation in invertebrates (of similar trophic level) may result from spatial variation in aqueous MeHg concentration or from more efficient uptake of aqueous MeHg into the pelagic food web. Our findings demonstrate that littoral-pelagic differences in MeHg bioaccumulation are widespread in small mid-latitude lakes. - Methylmercury levels in dominant invertebrate prey for fish differ between littoral and pelagic habitats within a lake.

Evaluation of bio-accumulation stress in chicken by arsenite: haematological case study

International Nuclear Information System (INIS)

Rasul, L.; Tufail, S.; Rasool, H.

2016-01-01

Water. This bio-accumulation disturbs the eco-physiological and blood parameters. Haematological studies of anti-coagulated and serum blood samples core parameters reveals that As (III) contamination in drinking water is the significant source of adverse disturbance of blood parameters of red blood cell, white blood cell, hemoglobin, packed cell volume, sodium, calcium, potassium ions, albumin, urea, creatinine and cholesterol, with a highly significant p value of less than 0.01 after 14th brooding day with bio-accumulation of 25.8 micro g/L of As (III) in blood samples. (author)

Speciation of bioaccumulated uranium(VI) by Euglena mutabilis cells obtained by laser fluorescence spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Brockmann, Sina; Bernhard, Gert [Technical Univ. Dresden (Germany). Radiochemistry; Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany). Inst. of Resource Ecology; Arnold, Thuro [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany). Inst. of Resource Ecology

2014-07-01

The ability of Euglena mutabilis cells - a unicellular protozoan with a flexible pellicle, which is typically found in acid mine drainage (AMD) environments - to bioaccumulate uranium under acid conditions was studied in batch sorption experiments at pH 3 and 4 using Na{sub 2}SO{sub 4} and NaClO{sub 4} as background media. It was found that axenic cultures of Euglena mutabilis Schmitz were able to bioaccumulate in 5 days 94.9 to 99.2% of uranium from a 1 x 10{sup -5} mol/L uranium solution in perchlorate medium and 95.1 to 95.9% in sodium sulfate medium, respectively. The speciation of uranium in solution and uranium bioaccumulated by Euglena mutabilis cells, were studied by laser induced fluorescence spectroscopy (LIFS). The LIFS investigations showed that the uranium speciation in the NaClO{sub 4} systems was dominated by free uranyl(VI) species and that the UO{sub 2}SO{sub 4} species was dominating in the Na{sub 2}SO{sub 4} medium. Fluorescence spectra of the bioaccumulated uranium revealed that aqueous uranium binds to carboxylic and/or (organo)phosphate groups located on the euglenid pellicle or inside the Euglena mutabilis cells. Reduced uranium immobilization rates of 0.93-1.43 mg uranium per g Euglena mutabilis biomass were observed in similar experiments, using sterile filtrated AMD waters containing, 4.4 x 10{sup -5} mol/L uranium. These lower rates were attributed to competition with other cations for available sorption sites. Additional LIFS measurements, however, showed that the speciation of the bioaccumulated uranium by the Euglena mutabilis cells was found to be identical with the uranium speciation found in the bioaccumulation experiments carried out in Na{sub 2}SO{sub 4} and NaClO{sub 4} media. The results indicate that Euglena mutabilis has the potential to immobilize aqueous uranium under acid condition and thus may be used in future as promising agent for immobilizing uranium in low pH waste water environments. (orig.)

Speciation of bioaccumulated uranium(VI) by Euglena mutabilis cells obtained by laser fluorescence spectroscopy

International Nuclear Information System (INIS)

Brockmann, Sina; Bernhard, Gert; Helmholtz-Zentrum Dresden-Rossendorf; Arnold, Thuro

2014-01-01

The ability of Euglena mutabilis cells - a unicellular protozoan with a flexible pellicle, which is typically found in acid mine drainage (AMD) environments - to bioaccumulate uranium under acid conditions was studied in batch sorption experiments at pH 3 and 4 using Na 2 SO 4 and NaClO 4 as background media. It was found that axenic cultures of Euglena mutabilis Schmitz were able to bioaccumulate in 5 days 94.9 to 99.2% of uranium from a 1 x 10 -5 mol/L uranium solution in perchlorate medium and 95.1 to 95.9% in sodium sulfate medium, respectively. The speciation of uranium in solution and uranium bioaccumulated by Euglena mutabilis cells, were studied by laser induced fluorescence spectroscopy (LIFS). The LIFS investigations showed that the uranium speciation in the NaClO 4 systems was dominated by free uranyl(VI) species and that the UO 2 SO 4 species was dominating in the Na 2 SO 4 medium. Fluorescence spectra of the bioaccumulated uranium revealed that aqueous uranium binds to carboxylic and/or (organo)phosphate groups located on the euglenid pellicle or inside the Euglena mutabilis cells. Reduced uranium immobilization rates of 0.93-1.43 mg uranium per g Euglena mutabilis biomass were observed in similar experiments, using sterile filtrated AMD waters containing, 4.4 x 10 -5 mol/L uranium. These lower rates were attributed to competition with other cations for available sorption sites. Additional LIFS measurements, however, showed that the speciation of the bioaccumulated uranium by the Euglena mutabilis cells was found to be identical with the uranium speciation found in the bioaccumulation experiments carried out in Na 2 SO 4 and NaClO 4 media. The results indicate that Euglena mutabilis has the potential to immobilize aqueous uranium under acid condition and thus may be used in future as promising agent for immobilizing uranium in low pH waste water environments. (orig.)

The stability of the hydroxylated (0001) surface of alpha-Al2O3

DEFF Research Database (Denmark)

Lodziana, Zbigniew; Nørskov, Jens Kehlet; Stoltze, Per

2003-01-01

Self-consistent density functional calculations of the hydroxylated (0001) corundum surfaces are presented. It is demonstrated that the hydroxylated surfaces are the most stable under most, but not all, conditions. Hydroxylation significantly lowers the surface free energy of alpha-alumina. The s......Self-consistent density functional calculations of the hydroxylated (0001) corundum surfaces are presented. It is demonstrated that the hydroxylated surfaces are the most stable under most, but not all, conditions. Hydroxylation significantly lowers the surface free energy of alpha......-alumina. The stability of the hydrated surface resolves the discrepancies between the morphology of the alpha-alumina (0001) surface observed under ultra-high vacuum, and at ambient conditions. A method for the calculation of the equilibrium surface stoichiometry is proposed. The proposed approach provides a valuable...

Feeding reduces waterborne Cu bioaccumulation in a marine rabbitfish Siganus oramin

International Nuclear Information System (INIS)

Guo, Zhiqiang; Zhang, Wei; Du, Sen; Zhou, Yanyan; Gao, Na; Zhang, Li; Green, Iain

2016-01-01

Waterborne metal uptake has been extensively studied and dietary metal assimilation is increasingly recognized in fish, whilst the interaction between the two uptake routes is largely overlooked. This study compared the waterborne Cu bioaccumulation ("6"5Cu as tracer) in a juvenile rabbitfish at different feeding regimes (starvation (SG), feeding normal diet (NDG) or diet supplemented with extra Cu (DCG)) to test the hypothesis that feeding can influence waterborne metal uptake in marine fish. NDG and DCG diet was fed as a single meal and then all fish were exposed to waterborne "6"5Cu for 48 h, during which the time course sampling was conducted to determine "6"5Cu bioaccumulation, chyme flow and dietary Cu assimilation. The results revealed that SG fish accumulated the highest "6"5Cu, followed by NDG (61% of SG), whilst DCG fish accumulated the lowest "6"5Cu (34% of SG). These results suggested a protective effect of feeding against waterborne Cu bioaccumulation. This effect was most notable between 10 min and 16 h when there was chyme in gastrointestinal tract (GT). Dietary Cu assimilation mainly occurred before 16 h after feeding. Waterborne "6"5Cu influx rate in the GT was positively correlated with "6"5Cu contents of chyme in NDG, whereas it was largely negatively correlated with "6"5Cu contents of chyme in DCG. The waterborne Cu uptake in the GT was mainly influenced by the chyme flow and dietary Cu assimilation. Overall, our findings suggested that feeding has an important effect on waterborne metal uptake and that both the feeding status of the fish and the relative metal exposure through water and food should be considered in prediction of the metal bioaccumulation and biomonitoring programs. - Highlights: • Feeding shows a protective effect against waterborne Cu uptake in fish. • The elevated dietary Cu can greatly suppress the waterborne Cu uptake. • The presence of chyme reduces Cu uptake in the gastrointestinal tract. • Feeding status has

Tuning the Slide-Roll Motion Mode of Carbon Nanotubes via Hydroxyl Groups

Science.gov (United States)

Li, Rui; Wang, Shiwei; Peng, Qing

2018-05-01

Controlling the motion of carbon nanotubes is critical in manipulating nanodevices, including nanorobots. Herein, we investigate the motion behavior of SWCNT (10,10) on Si substrate utilizing molecular dynamics simulations. We show that hydroxyl groups have sensitive effect on the carbon nanotube's motion mode. When the hydroxyl groups' ratio on carbon nanotube and silicon substrate surfaces is larger than 10 and 20%, respectively, the motion of carbon nanotube transforms from sliding to rolling. When the hydroxyl groups' ratio is smaller, the slide or roll mode can be controlled by the speed of carbon nanotube, which is ultimately determined by the competition between the interface potential energy and kinetic energy. The change of motion mode holds true for different carbon nanotubes with hydroxyl groups. The chirality has little effect on the motion behavior, as opposed to the diameter, attributed to the hydroxyl groups' ratio. Our study suggests a new route to control the motion behavior of carbon nanotube via hydroxyl groups.

Bioaccumulation of Fe2O3(magnetic) nanoparticles in Ceriodaphnia dubia

International Nuclear Information System (INIS)

Hu Ji; Wang Demin; Wang Jiangtao; Wang Jianmin

2012-01-01

While nano-Fe 2 O 3 (magnetic) is generally considered non-toxic, it could serve as a carrier of other toxic chemicals such as As(V) and enhance their toxicity. The bioaccumulation of nano-Fe 2 O 3 (m) with different exposure times, NP concentrations, and pH conditions was investigated using Ceriodaphnia dubia (C. dubia) as the model organism. Under natural pH conditions, C. dubia significantly accumulated nano-Fe 2 O 3 (m) in the gut, with the maximum accumulation being achieved after 6 h of exposure. The concentration of nano-Fe 2 O 3 also impacted its accumulation, with the maximum uptake occurring at 20 mg/L or more. In addition, the highest bioaccumulation occurred in a pH range of 7–8 where the highest feeding rate was reported, confirming that the ingestion of NPs is the main route of nano-Fe 2 O 3 (m) bioaccumulation. In a clean environment without NPs, depuration of nano-Fe 2 O 3 (m) occurred, and food addition accelerated the depuration process. - Highlights: ► Nano-Fe 2 O 3 (m) enhances the toxicity of As(V). ► C. dubia significantly accumulate nano-Fe 2 O 3 (m) through ingestion. ► The bioaccumulation of nano-Fe 2 O 3 (m) is affected by time, NP concentration, and pH. ► Food addition accelerates the depuration process of accumulated nano-Fe 2 O 3 (m). - Nano-Fe 2 O 3 (m) could enhance the toxicity of As(V) due to the significant accumulation of nano-Fe 2 O 3 (m) along with sorbed As(V) by C. dubia through ingestion.

Relationship between the lability of sediment-bound Cd and its bioaccumulation in edible oyster.

Science.gov (United States)

Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita; Chennuri, Kartheek; Bardhan, Pratirupa

2015-11-15

A linkage between Cd speciation in sediments and its bioaccumulation in edible oyster (Crassostrea sp.) from a tropical estuarine system was established. Bioaccumulation of Cd in edible oyster increased with the increasing lability and dissociation rate constants of Cd-sediment complexes in the bottom sediments. Total Cd concentration in sediment was not a good indicator of Cd-bioavailability. Increasing trace metal competition in sediments increased lability and bioavailability of Cd in the tropical estuarine sediment. Low thermodynamic stability and high bioavailability of Cd in the estuarine sediment were responsible for high bioaccumulation of Cd in edible oysters (3.2-12.2mgkg(-1)) even though the total concentration of Cd in the bottom sediment was low (0.17-0.49mgkg(-1)). Copyright © 2015 Elsevier Ltd. All rights reserved.

Enantioselective bioaccumulation of diniconazole in Tenebrio molitor larvae.

Science.gov (United States)

Liu, Chen; LV, Xiao Tian; Zhu, Wen Xue; QU, Hao Yang; Gao, Yong Xin; Guo, Bao Yuan; Wang, Hui Li

2013-12-01

The enantioselective bioaccumulation of diniconazole in Tenebrio molitor Linne larva was investigated with liquid chromatography tandem mass spectrometry based on the ChiralcelOD-3R[cellulose tri-(3,5-dimethylphenyl carbamate)] column. In this study we documented the effects of dietary supplementation with wheat bran contaminated by racemic diniconazole at two dose levels of 20 mg kg(-1) and 2 mg kg(-1) (dry weight) in Tenebrio molitor. The results showed that both doses of diniconazole were taken up by Tenebrio molitor rapidly in the first few days, the concentrations of R-enantiomer and S-enantiomer at high doses reached the highest level of 0.55 mg kg(-1) and 0.48 mg kg(-1) , respectively, on the 1(st) d, and the concentrations of them obtained a maxima of 0.129 mg kg(-1) and 0.128 mg kg(-1) at low dose, respectively, on the 3(rd) d, which means that the concentration of diniconazole was proportional to the time of achieving the highest accumulated level. It afterwards attained equilibrium after a sharp decline at both 20 mg kg(-1) and 2 mg kg(-1) of diniconazole. The determination results from the feces of Tenebrio molitor demonstrated that the extraction recovery (ER) values of the high dose group were higher than that of the low dose group and the values were all above 1; therefore, it could be inferred that enantiomerization existed in Tenebrio molitor. Additionally, the biota accumulation factor was used to evaluate the bioaccumulation of diniconazole enantiomers, showing that the bioaccumulation of diniconazole in Tenebrio molitor was enantioselective with preferential accumulation of S-enantiomer. © 2013 Wiley Periodicals, Inc.

Tissue-specific bioaccumulation of human and veterinary antibiotics in bile, plasma, liver and muscle tissues of wild fish from a highly urbanized region

International Nuclear Information System (INIS)

Zhao, Jian-Liang; Liu, You-Sheng; Liu, Wang-Rong; Jiang, Yu-Xia; Su, Hao-Chang; Zhang, Qian-Qian; Chen, Xiao-Wen; Yang, Yuan-Yuan; Chen, Jun; Liu, Shuang-Shuang; Pan, Chang-Gui; Huang, Guo-Yong; Ying, Guang-Guo

2015-01-01

We investigated the bioaccumulation of antibiotics in bile, plasma, liver and muscle tissues of wild fish from four rivers in the Pearl River Delta region. In total, 12 antibiotics were present in at least one type of fish tissues from nine wild fish species in the four rivers. The mean values of log bioaccumulation factors (log BAFs) for the detected antibiotics in fish bile, plasma, liver, and muscle tissues were at the range of 2.06–4.08, 1.85–3.47, 1.41–3.51, and 0.48–2.70, respectively. As the digestion tissues, fish bile, plasma, and liver showed strong bioaccumulation ability for some antibiotics, indicating a different bioaccumulation pattern from hydrophobic organic contaminants. Human health risk assessment based on potential fish consumption indicates that these antibiotics do not appear to pose an appreciable risk to human health. To the best of our knowledge, this is first report of bioaccumulation patterns of antibiotics in wild fish bile and plasma. - Highlights: • We investigated the bioaccumulation of antibiotics in wild fish from the Pearl River Delta region. • Twelve antibiotics were found in fish bile, plasma, liver and muscle tissues. • High log bioaccumulation factors suggested strong bioaccumulation ability for some antibiotics in wild fish tissues. • The presence of antibiotics in fish bile and plasma tissues indicates a novel bioaccumulation pattern. • Potential adverse effects are possibly caused by the high internal antibiotic concentrations in tissues. - Fish bile and plasma displayed strong bioaccumulation ability for some antibiotics, indicating a novel bioaccumulation pattern for antibiotics in the contaminated environment

PCDD/F and dioxin-like PCB bioaccumulation by Manila clam from polluted areas of Venice lagoon (Italy)

International Nuclear Information System (INIS)

Sfriso, Adriano; Facca, Chiara; Raccanelli, Stefano

2014-01-01

POP bioaccumulation pathways in the clam Tapes philippinarum were examined for two years from juveniles to adult size. Two polluted sites, one with sandy sediment, the other muddy were compared with a reference site characterized by low contamination levels. Juvenile clams coming from a hatchery were reared both on the sediment and in nets suspended at 30 cm from the bottom. POP changes in clam tissue were related to the concentrations recorded in sediments and in the particulate matter during the entire fattening period. Results provided interesting data on the relationships between environmental contamination and bioaccumulation. Contrary to studies on the decontamination times of the clams collected in polluted areas, this work investigates the preferential clam bioaccumulation pathways during growth under different environmental conditions. In general POP bioaccumulation resulted to be correlated to concentrations in SPM rather than in sediments and was higher in S-clams rather than in B-clams. -- Highlights: • PCDD/Fs and dioxin-like PCB accumulation in clam tissues during growth. • Muddy and sandy polluted areas. • How sediment and suspended matter contamination affect clam toxicity. • Clam toxicity and law limits. -- Clam bioaccumulation pathways in polluted areas

Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

Energy Technology Data Exchange (ETDEWEB)

Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

2015-12-29

Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

Fate, partitioning, and mass loading of polybrominated diphenyl ethers (PBDEs) during the treatment processing of municipal sewage.

Science.gov (United States)

Song, Min; Chu, Shaogang; Letcher, Robert J; Seth, Rajesh

2006-10-15

Sewage treatment plant (STP) effluents are likely a major source of contamination for PBDEs, especially in the receiving water bodies of local aquatic environments surrounding the location of these discharges. Congeners of the pentaBDE mixture, 2,2,',4,4'-tetrabromodiphenyl ether (BDE47), 2,2,',4,4',5-pentabromodiphenyl ether (BDE99), 2,2,',4,4',6-pentabromodiphenyl ether (BDE100), 2,2,',4,4',5,5'-hexabromodiphenyl ether (BDE153), and 2,2,',4,4',5,6'-hexabromodiphenyl ether (BDE154), are of great environmental concern in North America due to their persistence, potential for bioaccumulation, and >97% use of the global production of the mixture in the region. Detailed characterization of the distribution of eight PBDE congeners (2,4,4'-tribromoDE (BDE28) and BDE47, 99, 100, 138, 153, 154, and 183) was carried out at five sites along the treatment process at an activated sludge-type secondary treatment municipal STP facility. PentaBDE mixture congeners, sigma5PBDE (sum of BDE47, 99, 100, 153, and 154) accounted for >98% of the total (sigma 8) PBDE concentration at all sites, with over 80% of the composition being BDE47 and BDE99. Presence of dissolved organic matter affected the mobility of PBDEs during the initial stages of the treatment process. About 9% of the influent mass of sigma5PBDE to the facility is estimated to be discharged into the Little River (leading to the Detroit River) with the final effluent, resulting in an estimated mass loading of approximately 0.7 kg/year. The total mass loading of sigma5PBDE to the Detroit River is expected to be much larger as effluent from this facility accounts for <10% of the total STP discharges to the river.

Polybrominated diphenyl ethers: occurrence, dietary exposure, and toxicology.

Science.gov (United States)

Darnerud, P O; Eriksen, G S; Jóhannesson, T; Larsen, P B; Viluksela, M

2001-03-01

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in plastics (concentration, 5--30%) and in textile coatings. Commercial products consist predominantly of penta-, octa-, and decabromodiphenyl ether mixtures, and global PBDE production is about 40,000 tons per year. PBDEs are bioaccumulated and biomagnified in the environment, and comparatively high levels are often found in aquatic biotopes from different parts of the world. During the mid-1970--1980s there was a substantial increase in the PBDE levels with time in both sediments and aquatic biota, whereas the latest Swedish data (pike and guillemot egg) may indicate that levels are at steady state or are decreasing. However, exponentially increasing PBDE levels have been observed in mother's milk during 1972--1997. Based on levels in food from 1999, the dietary intake of PBDE in Sweden has been estimated to be 0.05 microg per day. Characteristic end points of animal toxicity are hepatotoxicity, embryotoxicity, and thyroid effects as well as maternal toxicity during gestation. Recently, behavioral effects have been observed in mice on administration of PBDEs during a critical period after birth. Based on the critical effects reported in available studies, we consider the lowest-observed-adverse-effect level (LOAEL) value of the PBDE group to be 1 mg/kg/day (primarily based on effects of pentaBDEs). In conclusion, with the scientific knowledge of today and based on Nordic intake data, the possible consumer health risk from PBDEs appears limited, as a factor of over 10(6) separates the estimated present mean dietary intake from the suggested LOAEL value. However, the presence of many and important data gaps, including those in carcinogenicity, reproduction, and developmental toxicity, as well as additional routes of exposure, make this conclusion only preliminary. Moreover, the time trend of PBDEs in human breast milk is alarming for the future.

Polybrominated diphenylethers (PBDES) in fish samples of various origin

Energy Technology Data Exchange (ETDEWEB)

Paepke, O.; Herrmann, T. [ERGO Research, Hamburg (Germany)

2004-09-15

Polybrominated diphenylethers (PBDEs) are widely used as flame retardants in polymer materials, textiles, electronic boards and various other materials. Technical PBDE preparations are produced as mixtures of mainly penta-, octa- or decabrombiphenyl ethers. PBDEs are structurally similar to other environmental pollutants like dioxins and PCBs, they are lipophilic and persistent components and widespread in the environment. For certain congeners bioaccumulation has been observed. Due to recent findings of increasing values in humans, food investigations for this group of components become raising importance. An early investigation for PBDEs in food from the German market has been performed by Krueger. In general, here is only limited information for PBDE of actual food in Germany. Because of the importance of fish for the estimated dietary intake of PBDEs by adults, actual information for Germany is needed. This papers gives an impression of the contamination of a limited number of fish samples bought on the German market in mid 2003.

Zinc bioaccumulation by microbial consortium isolated from nickel smelter sludge disposal site

Directory of Open Access Journals (Sweden)

Kvasnová Simona

2017-06-01

Full Text Available Heavy metal pollution is one of the most important environmental issues of today. Bioremediation by microorganisms is one of technologies extensively used for pollution treatment. In this study, we investigated the heavy metal resistance and zinc bioaccumulation by microbial consortium isolated from nickel sludge disposal site near Sereď (Slovakia. The composition of consortium was analyzed based on MALDI-TOF MS of cultivable bacteria and we have shown that the consortium was dominated by bacteria of genus Arthrobacter. While consortium showed very good growth in the zinc presence, it was able to remove only 15 % of zinc from liquid media. Selected members of consortia have shown lower growth rates in the zinc presence but selected isolates have shown much higher bioaccumulation abilities compared to whole consortium (up to 90 % of zinc removal for NH1 strain. Bioremediation is frequently accelerated through injection of native microbiota into a contaminated area. Based on data obtained in this study, we can conclude that careful selection of native microbiota could lead to the identification of bacteria with increased bioaccumulation abilities.

Cyanotoxins: Bioaccumulation and Effects on Aquatic Animals

Directory of Open Access Journals (Sweden)

Betina Kozlowsky-Suzuki

2011-12-01

Full Text Available Cyanobacteria are photosynthetic prokaryotes with wide geographic distribution that can produce secondary metabolites named cyanotoxins. These toxins can be classified into three main types according to their mechanism of action in vertebrates: hepatotoxins, dermatotoxins and neurotoxins. Many studies on the effects of cyanobacteria and their toxins over a wide range of aquatic organisms, including invertebrates and vertebrates, have reported acute effects (e.g., reduction in survivorship, feeding inhibition, paralysis, chronic effects (e.g., reduction in growth and fecundity, biochemical alterations (e.g., activity of phosphatases, GST, AChE, proteases, and behavioral alterations. Research has also focused on the potential for bioaccumulation and transferring of these toxins through the food chain. Although the herbivorous zooplankton is hypothesized as the main target of cyanotoxins, there is not unquestionable evidence of the deleterious effects of cyanobacteria and their toxins on these organisms. Also, the low toxin burden in secondary consumers points towards biodilution of microcystins in the food web as the predominant process. In this broad review we discuss important issues on bioaccumulation and the effects of cyanotoxins, with emphasis on microcystins, as well as drawbacks and future needs in this field of research.

Cyanotoxins: bioaccumulation and effects on aquatic animals.

Science.gov (United States)

Ferrão-Filho, Aloysio da S; Kozlowsky-Suzuki, Betina

2011-12-01

Cyanobacteria are photosynthetic prokaryotes with wide geographic distribution that can produce secondary metabolites named cyanotoxins. These toxins can be classified into three main types according to their mechanism of action in vertebrates: hepatotoxins, dermatotoxins and neurotoxins. Many studies on the effects of cyanobacteria and their toxins over a wide range of aquatic organisms, including invertebrates and vertebrates, have reported acute effects (e.g., reduction in survivorship, feeding inhibition, paralysis), chronic effects (e.g., reduction in growth and fecundity), biochemical alterations (e.g., activity of phosphatases, GST, AChE, proteases), and behavioral alterations. Research has also focused on the potential for bioaccumulation and transferring of these toxins through the food chain. Although the herbivorous zooplankton is hypothesized as the main target of cyanotoxins, there is not unquestionable evidence of the deleterious effects of cyanobacteria and their toxins on these organisms. Also, the low toxin burden in secondary consumers points towards biodilution of microcystins in the food web as the predominant process. In this broad review we discuss important issues on bioaccumulation and the effects of cyanotoxins, with emphasis on microcystins, as well as drawbacks and future needs in this field of research.

Comparing humic substance and protein compound effects on the bioaccumulation of perfluoroalkyl substances by Daphnia magna in water.

Science.gov (United States)

Xia, Xinghui; Dai, Zhineng; Rabearisoa, Andry Harinaina; Zhao, Pujun; Jiang, Xiaoman

2015-01-01

The influence of humic substances and protein compounds on the bioaccumulation of six types of perfluoroalkyl substances (PFASs) in Daphnia magna was compared. The humic substances included humic acid (HA) and fulvic acid (FA), the protein compounds included chicken egg albumin (albumin) and peptone, and the PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Four concentrations (0, 1, 10, and 20 mg L(-1)) of the four dissolved organic matter (DOM) types were investigated. At the 1 mg L(-1) level, HA and albumin enhanced all tested PFAS bioaccumulation, whereas FA and peptone only enhanced the bioaccumulation of shorter-chain PFASs (PFOS, PFOA, and PFNA). However, all four DOM types decreased all tested PFAS bioaccumulation at the 20 mg L(-1) level, and the decreasing ratios of bioaccumulation factors caused by FA, HA, albumin, and peptone were 1-49%, 23-77%, 17-58%, and 8-56%, respectively compared with those without DOM. This is because DOM not only reduced the bioavailable concentrations and uptake rates of PFASs but also lowered the elimination rates of PFASs in D. magna, and these opposite effects would change with different DOM types and concentrations. Although the partition coefficients (L kg(-1)) of PFASs between HA and water (10(4.21)-10(4.98)) were much lower than those between albumin and water (10(4.92)-10(5.86)), their effects on PFAS bioaccumulation were comparable. This study suggests that although PFASs are a type of proteinophilic compounds, humic substances also have important effects on their bioavailability and bioaccumulation in aquatic organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Estimation of Anaerobic Debromination Rate Constants of PBDE Pathways Using an Anaerobic Dehalogenation Model.

Science.gov (United States)

Karakas, Filiz; Imamoglu, Ipek

2017-04-01

This study aims to estimate anaerobic debromination rate constants (k m ) of PBDE pathways using previously reported laboratory soil data. k m values of pathways are estimated by modifying a previously developed model as Anaerobic Dehalogenation Model. Debromination activities published in the literature in terms of bromine substitutions as well as specific microorganisms and their combinations are used for identification of pathways. The range of estimated k m values is between 0.0003 and 0.0241 d -1 . The median and maximum of k m values are found to be comparable to the few available biologically confirmed rate constants published in the literature. The estimated k m values can be used as input to numerical fate and transport models for a better and more detailed investigation of the fate of individual PBDEs in contaminated sediments. Various remediation scenarios such as monitored natural attenuation or bioremediation with bioaugmentation can be handled in a more quantitative manner with the help of k m estimated in this study.

Bioaccumulation and effects of perfluorinated compounds (PFCs) in zebra mussels (Dreissena polymorpha).

Science.gov (United States)

Fernández-Sanjuan, María; Faria, Melissa; Lacorte, Silvia; Barata, Carlos

2013-04-01

Perfluorinated chemicals (PFCs) have been used for many years in numerous industrial products and are known to accumulate in organisms. A recent survey showed that tissue levels of PFCs in aquatic organisms varied among compounds and species being undetected in freshwater zebra mussels Dreissena polymorpha. Here we studied the bioaccumulation kinetics and effects of two major PFCs, perfluorooctane sulfonic acid compound (PFOS) and perfluorooctanoic acid (PFOA), in multixenobiotic transporter activity (MXR) and filtration and oxygen consumption rates in zebra mussel exposed to a range of concentrations of a PCF mixture (1-1,000 μg/L) during 10 days. Results indicate a low potential of the studied PFCs to bioaccumulate in zebra mussel tissues. PFCs altered mussel MXR transporter activity being inhibited at day 1 but not at day 10. Bioaccumulation kinetics of PFCs were inversely related with MXR transporter activity above 9 ng/g wet weight and unrelated at tissue concentration lower than 2 ng/g wet weight suggesting that at high tissue concentrations, these type of compounds may be effluxed out by MXR transporters and as a result have a low potential to be bioaccumulated in zebra mussels. Oxygen consumption rates but not filtering rates were increased in all exposure levels and periods indicating that at environmental relevant concentrations of 1 μg/L, the studied PFCs enhanced oxidative metabolism of mussels. Overall, the results obtained in this study confirm previous findings in the field indicating that an important fraction of PFC accumulated in mussel tissues is eliminated actively by MXR transporters or other processes that are metabolically costly.

Effect of curcumin against oxidation of biomolecules by hydroxyl radicals.

Science.gov (United States)

Borra, Sai Krishna; Mahendra, Jaideep; Gurumurthy, Prema; Jayamathi; Iqbal, Shabeer S; Mahendra, Little

2014-10-01

Among various reactive oxygen species, hydroxyl radicals have the strongest chemical activity, which can damage a wide range of essential biomolecules such as lipids, proteins, and DNA. The objective of this study was to investigate the beneficial effects of curcumin on prevention of oxidative damage of biomolecules by hydroxyl radicals generated in in vitro by a Fenton like reaction. We have incubated the serum, plasma and whole blood with H2O2/Cu2+/ Ascorbic acid system for 4 hours at 37 0C and observed the oxidation of biomolecules like albumin, lipids, proteins and DNA. Curcumin at the concentrations of 50,100 and 200 μmoles, prevented the formation of ischemia modified albumin, MDA, protein carbonyls, oxidized DNA and increased the total antioxidant levels and GSH significantly. These observations suggest the hydroxyl radical scavenging potentials of curcumin and protective actions to prevent the oxidation of biomolecules by hydroxyl radicals.

Bioaccumulation of sediment-bound Cr-51, Ni-63 and C-14 by benthic invertebrates

International Nuclear Information System (INIS)

Kumblad, L.; Bradshaw, C.; Giled, M.

2004-01-01

Sediments in many areas of the Baltic Sea are highly contaminated with particle-reactive trace metals and/or radionuclides. These may be re-mobilised into aquatic food chains by bioaccumulation into benthic organisms. In this study, we examined and compared assimilation efficiencies and bioaccumulation kinetics (rates of uptake and elimination) of sediment-associated Cr-51, Ni-63 and organic-associated C- 14 in three common benthic invertebrates from the Baltic Sea (the bivalve Macoma balthica, the amphipod Monoporeia affinis and the priapulid worm Halicryptus spinulosus). There were differences between animals and radionuclides in both the rate of uptake and elimination and the maximum amount accumulated. Understanding how and to what degree different deposit-feeding benthic invertebrates are exposed to and bio-accumulate sediment-associated metals are important for both ecological risk assessment and management decisions in coastal ecosystems. (author)

Bioaccumulation studies with Eisenia fetida using an established degradation test system

Energy Technology Data Exchange (ETDEWEB)

Norr, C.; Riepert, F. [Biological Research Centre for Agriculture and Forestry, Inst. for Ecotoxicology and Ecochemistry in Plant Protection, Berlin (Germany)

2007-12-15

Background. Earthworms are considered as an appropriate test system to assess the bioaccumulation potential of substances in the terrestrial environment. For regulatory purposes test methods were developed and incorporated in the validation process. A test design that is particularly suited for testing {sup 14}C-labelled substances will be described here. This design was adapted from an established degradation test system for bioaccumulation tests with earthworms in soil. The antibiotic sulfadiazine was used as test substance in this study. Due to the biological activity and the widespread entering into soil by manure application, veterinary medicines have become the target of ecotoxicological risk assessment. A German research group provided the soil samples mixed with liquid pig manure, which contained the {sup 14}C-labelled test substance after having passed through the gut of animals. This exposure pathway reflects the real environmental conditions. Therefore, sulfadiazine was tested even though a significant bioaccumulation potential was not expected to be detected owing to its chemical properties. Methods. Two adult earthworms of the species Eisenia fetida were inserted in a 500 ml glass container filled with 100 g soil. The test substrate consisted of soil mixed with liquid manure containing {sup 14}C-sulfadiazine. The glass containers were fitted with a soda-lime trap, which is permeable for oxygen but absorbs produced CO{sub 2} and other volatile metabolites. As food source for the earthworms, 5 g of mashed potato powder was applied per test container at the beginning of the test. The levels of radioactivity in soil samples and earthworms were determined by combustion in an oxidizer over a four-week exposure phase. The test design follows the instructions described by the OECD draft guideline for testing the bioaccumulation behaviour of chemicals with oligochaetes in soil. (orig.)

Evaluating mercury bioaccumulation rates in fish using mark-recapture techniques

Science.gov (United States)

Mathews, T.; Surendran Nair, S.; McManamay, R.

2017-12-01

Mercury (Hg) bioaccumulation can be described by models of varying complexity, from the simplified bioconcentration factor which describes the partitioning of contaminants between water and the organism, to more sophisticated models which take into consideration speciation, complexation, and/or bioavailability. At contaminated sites, especially those that are undergoing remediation, it is helpful to have a dynamic framework to identify critical Hg sources and processes, and to predict time scales to recovery. However, understanding the relationship between changes in exposure concentrations and bioaccumulation rates remains a challenge. East Fork Poplar Creek (EFPC) is a Hg-contaminated stream located in East Tennessee. Over the past 30 years, various remediation actions have succeeded in significantly reducing Hg inputs to this stream. One of the major goals of remediation is to reduce Hg bioaccumulation in resident sunfish in order to meet human health guidelines. Mercury is measured in sunfish fillets bi-annually at various sites along the stream. Because Hg analysis requires only 100 mg of tissue, fish can be sampled non-lethally and released at the site of capture. Since 2008, passive induced transponder (PIT) tags have been used to identify individual fish that are collected from EFPC for Hg analysis. Approximately 10% of PIT tagged fish were recaptured, allowing for the measurement of growth rates and Hg bioaccumulation rates in individual fish. While traditional biomonitoring studies conducted in EFPC have found that the average Hg concentrations in sacrificed fish have not responded to changes in aqueous Hg concentrations over the past 10 years, data from the mark-recapture study show that individual fish may respond to changes in aqueous inorganic Hg concentrations on shorter time scales. Rapid changes in aqueous Hg concentrations over a four year period resulted in measurable increases and decreases in Hg concentrations in individual fish that could not

Characterization of the Ornithine Hydroxylation Step in Albachelin Biosynthesis

Directory of Open Access Journals (Sweden)

Kendra Bufkin

2017-10-01

Full Text Available N-Hydroxylating monooxygenases (NMOs are involved in siderophore biosynthesis. Siderophores are high affinity iron chelators composed of catechol and hydroxamate functional groups that are synthesized and secreted by microorganisms and plants. Recently, a new siderophore named albachelin was isolated from a culture of Amycolatopsis alba growing under iron-limiting conditions. This work focuses on the expression, purification, and characterization of the NMO, abachelin monooxygenase (AMO from A. alba. This enzyme was purified and characterized in its holo (FAD-bound and apo (FAD-free forms. The apo-AMO could be reconstituted by addition of free FAD. The two forms of AMO hydroxylate ornithine, while lysine increases oxidase activity but is not hydroxylated and display low affinity for NADPH.

Reductive debromination of polybrominated diphenyl ethers in anaerobic sediment and a biomimetic system.

Science.gov (United States)

Tokarz, John A; Ahn, Mi-Youn; Leng, June; Filley, Timothy R; Nies, Loring

2008-02-15

Because of the bioaccumulation of penta- and tetrapolybrominated diphenyl ether (PBDE) flame retardants in biota,the environmental biotransformation of decabromodiphenyl ether (BDE-209) is of interest. BDE-209 accounts for more than 80% by mass of PBDE production and is the dominant PBDE in sediments. Most sediments are anaerobic and reports of microbial reductive dehalogenation of hydrophobic persistent organohalogen pollutants are numerous. Reductive debromination of BDE-209 in the environment could provide a significant source of lesser-brominated PBDEs to biota. Moreover, a recent study showed that BDE-209 debrominates in sewage sludge, and another demonstrated that some halorespiring bacteria will debrominate BDE-209. To determine whether reductive debromination of BDE-209 occurs in sediments, parallel experiments were conducted using anaerobic sediment microcosms and a cosolvent-enhanced biomimetic system. In the biomimetic system, reductive debromination occurred at rates corresponding to bromine substitution levels with a BDE-209 half-life of only 18 s compared with a halflife of almost 60 days for 2,2',4,4'-tetrabromodiphenyl ether. In sediment, the measured debromination half-life of BDE-209 was well over a decade and was in good agreement with the predicted value obtained from the biomimetic experiment. Product congeners were predominantly double para-substituted. BDE-209 debrominated in sediment with a corresponding increase in nona-, octa-, hepta-, and hexa-PBDEs. Nine new PBDE congeners appeared in sediment from reductive debromination. Given the very large BDE-209 burden already in sediments globally, it is important to determine whether this transformation is a significant source of lesser-brominated PBDEs to the environment.

Hydroxyl radical reactivity at the air-ice interface

Directory of Open Access Journals (Sweden)

T. F. Kahan

2010-01-01

Full Text Available Hydroxyl radicals are important oxidants in the atmosphere and in natural waters. They are also expected to be important in snow and ice, but their reactivity has not been widely studied in frozen aqueous solution. We have developed a spectroscopic probe to monitor the formation and reactions of hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and react rapidly with benzene to form phenol. Similar phenol formation rates were observed in aqueous solution and bulk ice. However, no reaction was observed at air-ice interfaces, or when bulk ice samples were crushed prior to photolysis to increase their surface area. We also monitored the heterogeneous reaction between benzene present at air-water and air-ice interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol formation was observed on water surfaces, but no reaction was observed at the surface of ice. Under the same conditions, we observed rapid loss of the polycyclic aromatic hydrocarbon (PAH anthracene at air-water interfaces, but no loss was observed at air-ice interfaces. Our results suggest that the reactivity of hydroxyl radicals toward aromatic organics is similar in bulk ice samples and in aqueous solution, but is significantly suppressed in the quasi-liquid layer (QLL that exists at air-ice interfaces.

Improving plant bioaccumulation science through consistent reporting of experimental data

DEFF Research Database (Denmark)

Fantke, Peter; Arnot, Jon A.; Doucette, William J.

2016-01-01

Experimental data and models for plant bioaccumulation of organic contaminants play a crucial role for assessing the potential human and ecological risks associated with chemical use. Plants are receptor organisms and direct or indirect vectors for chemical exposures to all other organisms. As new...... experimental data are generated they are used to improve our understanding of plant-chemical interactions that in turn allows for the development of better scientific knowledge and conceptual and predictive models. The interrelationship between experimental data and model development is an ongoing, never......-ending process needed to advance our ability to provide reliable quality information that can be used in various contexts including regulatory risk assessment. However, relatively few standard experimental protocols for generating plant bioaccumulation data are currently available and because of inconsistent...

Bioaccumulation of Cs-137 and Co-57 by marine phytoplankton

International Nuclear Information System (INIS)

Heldal, H.E.; Stupakoff, I.; Fisher, N.S.

1999-01-01

Under controlled laboratory conditions we have examined the bioaccumulation of Cs-137 and Co-57 in three prymnesiophytes, the coccolithophorid Emiliania huxleyi and the non-calcareous species Isochrysis galbana and Phaeocystis globosa, and two diatoms Skeletonema costatum and Thalassiosira pseudonana. We measured uptake in growing and non-growing cells, and determined concentration factors on both volume and dry weight basis. For Co-57 uptake in non-growing cells, volume concentration factors (VCF) at equilibrium ranged from 0.2 * 10 3 for Emiliana huxleyi to 4 * 10 3 for the diatom Thalassiosira pseudonana. For Cs-137 uptake in non-growing cells the VCFs were close to zero. The results suggest that, in contrast to Co, the cycling and bioaccumulation in animals of Cs in marine systems is unlikely to be affected by primary producers. (au)

Platinum bioaccumulation by mustard plants (Sinapis alba L.)

International Nuclear Information System (INIS)

Hawienczyk, M.; Bystrzejewska-Piotrowska, G.; Kowalska, J.; Asztemborska, M.

2005-01-01

The ability of hydroponically cultivated Indian mustard plants (Sinapis alba L.) to accumulate platinum was investigated. The Pt-bioaccumulation in leaves, stem and shoots of plants growing for 2 and 4 weeks at Pt-concentration of 50 and 500 μg/L was compared. The relation between dry and fresh weight was also estimated. Adsorptive stripping voltammetry (AdSV) and mass spectrometry with inductively coupled plasma (ICP-MS) were applied for determination of Pt. Increasing Pt-concentration from 50 to 500 μg/L in the medium causes: (1) reduction of the root tissue hydration level at unchanged modification in aboveground parts of the plants and (2) decrease of the Pt transfer factor (TF) for roots and increase for leaves and stem. Duration of the culture influenced on Pt-accumulation in roots and in aboveground organs of mustard plants. Transfer factor for Pt between 560 and 1600 makes Indian mustard plants one at Pt-hyperaccumulators. Distribution of Pt-bioaccumulation in the plant organs may be useful for biomonitoring of platinum in the environment. (author)

Bioaccumulation of animal adenoviruses in the pink shrimp

Directory of Open Access Journals (Sweden)

Roger B. Luz

2015-09-01

Full Text Available Adenoviruses are among the most promising viral markers of fecal contamination. They are frequently found in the water, sediment and soil of regions impacted by human activity. Studies of the bioaccumulation of enteric viruses in shrimp are scarce. The cities located in the northern coast of the lake systems in Southern Brazil have high urbanization and intensive farming rates, and poor sewage collection and treatment. One hundred (n = 100 Farfantepenaeus paulensis pink-shrimp specimens and 48 water samples were collected from coastal lagoons between June 2012 and May 2013. Water samples were concentrated and the shrimp, mashed. After DNA extraction, samples were analyzed by real time polymerase chain reaction (qPCR in order to detect and quantify viral genomes. Thirty-five percent of shrimp samples were positive for contamination, predominantly by avian adenoviruses. A total of 91.7% of water samples contained adenoviruses DNA, with the human form being the most frequent. Our results provided evidence of significant bioaccumulation of adenoviruses in shrimp, showing the extent of the impact of fecal pollution on aquatic ecosystems.

Hydroxyl-dependent Evolution of Oxygen Vacancies Enables the Regeneration of BiOCl photocatalyst

KAUST Repository

Wu, Sujuan

2017-05-02

Photoinduced oxygen vacancies (OVs) are widely investigated as a vital point defect in wide-band-gap semiconductors. Still, the formation mechanism of OVs remains unclear in various materials. To elucidate the formation mechanism of photoinduced OVs in bismuth oxychloride (BiOCl), we synthesized two surface hydroxyl discrete samples in light of the discovery of the significant variance of hydroxyl groups before and after UV light exposure. It is noted that OVs can be obtained easily after UV light irradiation in the sample with surface hydroxyl groups, while variable changes were observed in samples without surface hydroxyls. Density functional theory (DFT) calculations reveal that the binding energy of Bi-O is drastically influenced by surficial hydroxyl groups, which is intensely correlated to the formation of photoinduced OVs. Moreover, DFT calculations reveal that the adsorbed water molecules are energetically favored to dissociate into separate hydroxyl groups at the OV sites via proton transfer to a neighboring bridging oxygen atom, forming two bridging hydroxyl groups per initial oxygen vacancy. This result is consistent with the experimental observation that the disappearance of photoinduced OVs and the recovery of hydroxyl groups on the surface of BiOCl after exposed to a H2O(g)-rich atmosphere, and finally enables the regeneration of BiOCl photocatalyst. Here, we introduce new insights that the evolution of photoinduced OVs is dependent on surface hydroxyl groups, which will lead to the regeneration of active sites in semiconductors. This work is useful for controllable designs of defective semiconductors for applications in photocatalysis and photovoltaics.

Organophosphorus and Organochlorine Pesticides Bioaccumulation by Eichhornia crassipes in Irrigation Canals in an Urban Agricultural System.

Science.gov (United States)

Mercado-Borrayo, B M; Cram Heydrich, Silke; Pérez, Irma Rosas; Hernández Quiroz, Manuel; De León Hill, Claudia Ponce

2015-01-01

A natural wetland in Mexico City Metropolitan Area is one of the main suppliers of crops and flowers, and in consequence its canals hold a high concentration of organochlorine (OC) and organophosphorus (OP) pesticides. There is also an extensive population of water hyacinth (Eichhornia crassipes), which is considered a plague; but literature suggests water hyacinth may be used as a phytoremediator. This study demonstrates bioaccumulation difference for the OC in vivo suggesting their bioaccumulation is ruled by their log K(ow), while all the OP showed bioaccumulation regardless of their log K(ow). The higher bioaccumulation factors (BAF) of the accumulated OC pesticides cannot be explained by their log K(ow), suggesting that the OC pesticides may also be transported passively into the plant. Translocation ratios showed that water hyacinth is an accumulating plant with phytoremediation potential for all organophosphorus pesticides studied and some organochlorine pesticides. An equation for free water surface wetlands with floating macrophytes, commonly used for the construction of water-cleaning wetlands, showed removal of the pesticides by the wetland with room for improvement with appropriate management.

In vitro to in vivo extrapolation of biotransformation rates for assessing bioaccumulation of hydrophobic organic chemicals in mammals.

Science.gov (United States)

Lee, Yung-Shan; Lo, Justin C; Otton, S Victoria; Moore, Margo M; Kennedy, Chris J; Gobas, Frank A P C

2017-07-01

Incorporating biotransformation in bioaccumulation assessments of hydrophobic chemicals in both aquatic and terrestrial organisms in a simple, rapid, and cost-effective manner is urgently needed to improve bioaccumulation assessments of potentially bioaccumulative substances. One approach to estimate whole-animal biotransformation rate constants is to combine in vitro measurements of hepatic biotransformation kinetics with in vitro to in vivo extrapolation (IVIVE) and bioaccumulation modeling. An established IVIVE modeling approach exists for pharmaceuticals (referred to in the present study as IVIVE-Ph) and has recently been adapted for chemical bioaccumulation assessments in fish. The present study proposes and tests an alternative IVIVE-B technique to support bioaccumulation assessment of hydrophobic chemicals with a log octanol-water partition coefficient (K OW ) ≥ 4 in mammals. The IVIVE-B approach requires fewer physiological and physiochemical parameters than the IVIVE-Ph approach and does not involve interconversions between clearance and rate constants in the extrapolation. Using in vitro depletion rates, the results show that the IVIVE-B and IVIVE-Ph models yield similar estimates of rat whole-organism biotransformation rate constants for hypothetical chemicals with log K OW  ≥ 4. The IVIVE-B approach generated in vivo biotransformation rate constants and biomagnification factors (BMFs) for benzo[a]pyrene that are within the range of empirical observations. The proposed IVIVE-B technique may be a useful tool for assessing BMFs of hydrophobic organic chemicals in mammals. Environ Toxicol Chem 2017;36:1934-1946. © 2016 SETAC. © 2016 SETAC.

PCDD/F and dioxin-like PCB bioaccumulation by Manila clam from polluted areas of Venice lagoon (Italy).

Science.gov (United States)

Sfriso, Adriano; Facca, Chiara; Raccanelli, Stefano

2014-01-01

POP bioaccumulation pathways in the clam Tapes philippinarum were examined for two years from juveniles to adult size. Two polluted sites, one with sandy sediment, the other muddy were compared with a reference site characterized by low contamination levels. Juvenile clams coming from a hatchery were reared both on the sediment and in nets suspended at 30 cm from the bottom. POP changes in clam tissue were related to the concentrations recorded in sediments and in the particulate matter during the entire fattening period. Results provided interesting data on the relationships between environmental contamination and bioaccumulation. Contrary to studies on the decontamination times of the clams collected in polluted areas, this work investigates the preferential clam bioaccumulation pathways during growth under different environmental conditions. In general POP bioaccumulation resulted to be correlated to concentrations in SPM rather than in sediments and was higher in S-clams rather than in B-clams. Copyright © 2013 Elsevier Ltd. All rights reserved.

Anaerobic Dehalogenation of Hydroxylated Polychlorinated Biphenyls by Desulfitobacterium dehalogenans

OpenAIRE

Wiegel, Juergen; Zhang, Xiaoming; Wu, Qingzhong

1999-01-01

Ten years after reports on the existence of anaerobic dehalogenation of polychlorinated biphenyls (PCBs) in sediment slurries, we report here on the rapid reductive dehalogenation of para-hydroxylated PCBs (HO-PCBs), the excreted main metabolites of PCB in mammals, which can exhibit estrogenic and antiestrogenic activities in humans. The anaerobic bacterium Desulfitobacterium dehalogenans completely dehalogenates all flanking chlorines (chlorines in ortho position to the para-hydroxyl group) ...

Bioaccumulation of heavy metals in fauna from wet detention ponds for stormwater runoff

DEFF Research Database (Denmark)

Stephansen, Diana; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild

2012-01-01

Stormwater detention ponds remove pollutants e.g. heavy metals and nutrients from stormwater runoff. These pollutants accumulate in the pond sediment and thereby become available for bioaccumulation in fauna living in the ponds. In this study the bioaccumulation was investigated by fauna samples...... from 5 wet detention ponds for analyses of heavy metal contents. Five rural shallow lakes were included in the study to survey the natural occurrence of heavy metals in water-dwelling fauna. Heavy metal concentrations in water-dwelling fauna were generally found higher in wet detention ponds compared...

Influence of body size on Cu bioaccumulation in zebra mussels Dreissena polymorpha exposed to different sources of particle-associated Cu

Energy Technology Data Exchange (ETDEWEB)

Zhong, Huan, E-mail: huanzhong1982@hotmail.com [Environmental and Resource Studies Program, Trent University, Peterborough, Ontario (Canada); Nanjing University, School of Environment, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province (China); Kraemer, Lisa; Evans, Douglas [Environmental and Resource Studies Program, Trent University, Peterborough, Ontario (Canada)

2013-10-15

Highlights: • Mussels exposed to algal/sediment-Cu have different size-related Cu accumulation. • Size-related Cu accumulation in mussels could be more dependant on algal-Cu uptake. • Importance of algal/sediment-Cu to Cu bioaccumulation varies with mussel body size. • Cu sources (algae and sediments) should be considered in “mussel watch” programs. • Cu stable isotope offers many advantages in Cu bioaccumulation studies. -- Abstract: Size of organisms is critical in controlling metal bioavailability and bioaccumulation, while mechanisms of size-related metal bioaccumulation are not fully understood. To investigate the influences of different sources of particle-associated Cu on body size-related Cu bioavailability and bioaccumulation, zebra mussels (Dreissena polymorpha) of different sizes were exposed to stable Cu isotope ({sup 65}Cu) spiked algae (Chlorella vulgaris) or sediments in the laboratory and the Cu tissue concentration-size relationships were compared with that in unexposed mussels. Copper tissue concentrations decreased with mussel size (tissue or shell dry weight) in both unexposed and algal-exposed mussels with similar decreasing patterns, but were independent of size in sediment-exposed mussels. Furthermore, the relative contribution of Cu uptake from algae (65–91%) to Cu bioaccumulation is always higher than that from sediments (9–35%), possibly due to the higher bioavailability of algal-Cu. Therefore, the size-related ingestion of algae could be more important in influencing the size-related variations in Cu bioaccumulation. However, the relative contribution of sediment-Cu to Cu bioaccumulation increased with body size and thus sediment ingestion may also affect the size-related Cu variations in larger mussels (tissue weight >7.5 mg). This study highlights the importance of considering exposure pathways in normalization of metal concentration variation when using bivalves as biomonitors.

Towards a proportionality assessment of risk reduction measures aimed at restricting the use of persistent and bioaccumulative substances.

NARCIS (Netherlands)

Oosterhuis, Frans; Brouwer, Roy; Janssen, Martien; Verhoeven, Julia; Luttikhuizen, Cees

2017-01-01

International chemicals legislation aims at adequately controlling persistent organic pollutants (POPs) and substances of very high concern (SVHCs), such as persistent, bioaccumulative, and toxic (PBT) and very persistent and very bioaccumulative (vPvB) substances, with a view to progressively

Bioaccumulation of Heavy Metals by Moringa Oleifera in Automobile ...

African Journals Online (AJOL)

Plants accumulate minerals essential for their growth from the environment alongside with heavy metals from contaminated areas.This study investigated bioaccumulation of heavy metals by Moringa oleifera in automobile workshops in three selected local government areas in Ibadan. This was done with a view to ...

Bioaccumulation and toxic effects of some heavy metals in ...

African Journals Online (AJOL)

The contamination of the aquatic systems with heavy metals from natural anthropogenic sources has become a global problem which poses threats to ecosystems and natural communities. Hence this study reviews the effects of heavy metals in freshwater fishes. Fishes bioaccumulate heavy metals (including cadmium, zinc ...

Functionalization of hydroxyl terminated polybutadiene with ...

Indian Academy of Sciences (India)

CBDT), has been covalently attached at the terminal carbon atoms of the hydroxyl terminated polybutadiene (HTPB) backbone. The modification of HTPB backbone by CBDT molecule does not affect the unique physico-chemical properties such ...

“One-shot” analysis of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogs in human breast milk and serum using gas chromatography-tandem mass spectrometry

International Nuclear Information System (INIS)

Butryn, Deena M.; Gross, Michael S.; Chi, Lai-Har; Schecter, Arnold; Olson, James R.; Aga, Diana S.

2015-01-01

The presence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-BDE) and methoxylated (MeO-BDE) analogs in humans is an area of high interest to scientists and the public due to their neurotoxic and endocrine disrupting effects. Consequently, there is a rise in the investigation of the occurrence of these three classes of compounds together in environmental matrices and in humans in order to understand their bioaccumulation patterns. Analysis of PBDEs, OH-BDEs, and MeO-BDEs using liquid chromatography-mass spectrometry (LC-MS) can be accomplished simultaneously, but detection limits for PBDEs and MeO-BDEs in LC-MS is insufficient for trace level quantification. Therefore, fractionation steps of the phenolic (OH-BDEs) and neutral (PBDEs and MeO-BDEs) compounds during sample preparation are typically performed so that different analytical techniques can be used to achieve the needed sensitivities. However, this approach involves multiple injections, ultimately increasing analysis time. In this study, an analytical method was developed for a “one-shot” analysis of 12 PBDEs, 12 OH-BDEs, and 13 MeO-BDEs using gas chromatography with tandem mass spectrometry (GC-MS/MS). This overall method includes simultaneous extraction of all analytes via pressurized liquid extraction followed by lipid removal steps to reduce matrix interferences. The OH-BDEs were derivatized using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (TBDMS-MTFA), producing OH-TBDMS derivatives that can be analyzed together with PBDEs and MeO-BDEs by GC-MS/MS in “one shot” within a 25-min run time. The overall recoveries were generally higher than 65%, and the limits of detection ranged from 2 to 14 pg in both breast milk and serum matrices. The applicability of the method was successfully validated on four paired human breast milk and serum samples. The mean concentrations of total PBDEs, OH-BDEs, and MeO-BDEs in breast milk were 59, 2.2, and 0.57 ng g −1 lipid

“One-shot” analysis of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogs in human breast milk and serum using gas chromatography-tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Butryn, Deena M.; Gross, Michael S. [Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Chi, Lai-Har [Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Schecter, Arnold [Department of Pharmacology and Toxicology, University of Louisville College of Medicine, Louisville, KY 40202 (United States); Olson, James R. [Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Aga, Diana S., E-mail: dianaaga@buffalo.edu [Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States)

2015-09-10

The presence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-BDE) and methoxylated (MeO-BDE) analogs in humans is an area of high interest to scientists and the public due to their neurotoxic and endocrine disrupting effects. Consequently, there is a rise in the investigation of the occurrence of these three classes of compounds together in environmental matrices and in humans in order to understand their bioaccumulation patterns. Analysis of PBDEs, OH-BDEs, and MeO-BDEs using liquid chromatography-mass spectrometry (LC-MS) can be accomplished simultaneously, but detection limits for PBDEs and MeO-BDEs in LC-MS is insufficient for trace level quantification. Therefore, fractionation steps of the phenolic (OH-BDEs) and neutral (PBDEs and MeO-BDEs) compounds during sample preparation are typically performed so that different analytical techniques can be used to achieve the needed sensitivities. However, this approach involves multiple injections, ultimately increasing analysis time. In this study, an analytical method was developed for a “one-shot” analysis of 12 PBDEs, 12 OH-BDEs, and 13 MeO-BDEs using gas chromatography with tandem mass spectrometry (GC-MS/MS). This overall method includes simultaneous extraction of all analytes via pressurized liquid extraction followed by lipid removal steps to reduce matrix interferences. The OH-BDEs were derivatized using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (TBDMS-MTFA), producing OH-TBDMS derivatives that can be analyzed together with PBDEs and MeO-BDEs by GC-MS/MS in “one shot” within a 25-min run time. The overall recoveries were generally higher than 65%, and the limits of detection ranged from 2 to 14 pg in both breast milk and serum matrices. The applicability of the method was successfully validated on four paired human breast milk and serum samples. The mean concentrations of total PBDEs, OH-BDEs, and MeO-BDEs in breast milk were 59, 2.2, and 0.57 ng g{sup −1} lipid

Antibiotics in typical marine aquaculture farms surrounding Hailing Island, South China: Occurrence, bioaccumulation and human dietary exposure

International Nuclear Information System (INIS)

Chen, Hui; Liu, Shan; Xu, Xiang-Rong; Liu, Shuang-Shuang; Zhou, Guang-Jie; Sun, Kai-Feng; Zhao, Jian-Liang; Ying, Guang-Guo

2015-01-01

Highlights: • Thirty-seven antibiotics were systematically investigated in typical marine aquaculture farms. • Enrofloxacin was widely detected in the feed samples (16.6–31.8 ng/g). • ETM-H 2 O in the adult shrimp samples may pose a potential risk to human safety. • TMP was bioaccumulative in fish muscles. • Antibiotics were weakly bioaccumulated in mollusks. - Abstract: The occurrence, bioaccumulation, and human dietary exposure via seafood consumption of 37 antibiotics in six typical marine aquaculture farms surrounding Hailing Island, South China were investigated in this study. Sulfamethoxazole, salinomycin and trimethoprim were widely detected in the water samples (0.4–36.9 ng/L), while oxytetracycline was the predominant antibiotic in the water samples of shrimp larvae pond. Enrofloxacin was widely detected in the feed samples (16.6–31.8 ng/g) and erythromycin–H 2 O was the most frequently detected antibiotic in the sediment samples (0.8–4.8 ng/g). Erythromycin–H 2 O was the dominant antibiotic in the adult Fenneropenaeus penicillatus with concentrations ranging from 2498 to 15,090 ng/g. In addition, trimethoprim was found to be bioaccumulative in young Lutjanus russelli with a median bioaccumulation factor of 6488 L/kg. Based on daily intake estimation, the erythromycin–H 2 O in adult F. penicillatus presented a potential risk to human safety

Bioaccumulation of heavy metals by Dyera costulata cultivated in ...

African Journals Online (AJOL)

High concentrations of heavy metals are harmful to plants, animals and humans and their potential accumulation in human tissues and bio-magnification through the food chain cause serious health hazards. An experiment was conducted in the glasshouse to evaluate the potential of Dyera costulata as a bioaccumulator to ...

Toxicity and bioaccumulation of sediment-associated contaminants using freshwater invertebrates: A review of methods and applications

Science.gov (United States)

Ingersoll, C.G.; Ankley, G.T.; Benoit, D.A.; Brunson, E.L.; Burton, G.A.; Dwyer, F.J.; Hoke, R.A.; Landrum, P.F.; Norberg-King, T. J.; Winger, P.V.

1995-01-01

This paper reviews recent developments in methods for evaluating the toxicity and bioaccumulation of contaminants associated with freshwater sediments and summarizes example case studies demonstrating the application of these methods. Over the past decade, research has emphasized development of more specific testing procedures for conducting 10-d toxicity tests with the amphipod Hyalella azteca and the midge Chironomus tentans. Toxicity endpoints measured in these tests are survival for H. azteca and survival and growth for C. tentans. Guidance has also been developed for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus, including determination of bioaccumulation kinetics for different compound classes. These methods have been applied to a variety of sediments to address issues ranging from site assessments to bioavailability of organic and inorganic contaminants using field-collected and laboratory-spiked samples. Survival and growth of controls routinely meet or exceed test acceptability criteria. Results of laboratory bioaccumulation studies with L. variegatus have been confirmed with comparisons to residues (PCBs, PAHs, DDT) present from synoptically collected field populations of oligochaetes. Additional method development is currently underway to develop chronic toxicity tests and to provide additional data-confirming responses observed in laboratory sediment tests with natural benthic populations.

Thermophysical properties of hydroxyl ammonium ionic liquids

International Nuclear Information System (INIS)

Kurnia, K.A.; Wilfred, C.D.; Murugesan, T.

2009-01-01

The thermophysical properties of hydroxyl ammonium ionic liquids: density ρ, T = (293.15 to 363.15) K; dynamic viscosity η, T = (298.2 to 348.2) K; and refractive indices n D , T = (293.15 to 333.15) K have been measured. The coefficients of thermal expansion α, values were calculated from the experimental density results using an empirical correlation for T = (293.15 to 363.15) K. The variation of volume expansion of ionic liquids studied was found to be independent of temperature within the range covered in the present work. The thermal decomposition temperature 'T d ' for all the six hydroxyl ammonium ionic liquids is also investigated using thermogravimetric analyzer (TGA)

Bioaccumulation of metals in constructed wetlands used to treat acid drainage

International Nuclear Information System (INIS)

Edwards, G.S.; Mays, P.A.

1994-01-01

Constructed wetlands are being used extensively as a potential mitigation for acid drainage. However, removal of metals to meet compliance requirements has varied among wetlands, ranging from partial to total success. In addition, wetlands are sinks for contaminants found in acid drainage, and bioaccumulation of these contaminants to levels that would adversely affect the food web is of growing concern. The primary objective of this project was to determine whether bioaccumulation of metals occurs in wetlands constructed for treatment of acid drainage. Water, sediment, plant and benthos samples were collected from two wetlands constructed by the Tennessee Valley Authority and a natural wetland in the spring and fall of 1992, and metal concentrations were determined. One of the constructed wetlands, Impoundment 1, has generally been in compliance for NPDES; the other, Widow's Creek, has never been in compliance. Preliminary results indicate similarities in sediment and plant metal concentrations between Impoundment 1 and the natural wetland and greater metal concentrations in the sediment and plants at Widow's Creek. Data also indicate that Mn, Zn, Cu, Ni, and Cr are being accumulated in the plants at each wetland. However, accumulation of metals by these plants probably accounts for only a small percentage of the removal of the annual metal load supplied to each wetland. Bioaccumulation of metals in the benthic organisms at each wetland is currently being investigated

Habitat type-based bioaccumulation and risk assessment of metal and As contamination in earthworms, beetles and woodlice

International Nuclear Information System (INIS)

Vermeulen, Frouke; Van den Brink, Nico W.; D'Have, Helga; Mubiana, Valentine K.; Blust, Ronny; Bervoets, Lieven; De Coen, Wim

2009-01-01

The present study investigated the contribution of environmental factors to the accumulation of As, Cd, Cu, Pb and Zn in earthworms, beetles and woodlice, and framed within an exposure assessment of the European hedgehog. Soil and invertebrate samples were collected in three distinct habitat types. Results showed habitat-specific differences in soil and invertebrate metal concentrations and bioaccumulation factors when normalized to soil metal concentration. Further multiple regression analysis showed residual variability (habitat differences) in bioaccumulation that could not be fully explained by differences in soil metal contamination, pH or organic carbon (OC). Therefore, the study demonstrated that in bioaccumulation studies involving terrestrial invertebrates or in risk assessment of metals, it is not sufficient to differentiate habitat types on general soil characteristics such as pH and/or OC alone. Furthermore, simple generic soil risk assessments for Cd and Cu showed that risk characterization was more accurate when performed in a habitat-specific way. - Our study provided essential insights into habitat-specific accumulation patterns with respect to factors influencing metal bioaccumulation, BAFs, and site-specific risk assessment.

Habitat type-based bioaccumulation and risk assessment of metal and As contamination in earthworms, beetles and woodlice

Energy Technology Data Exchange (ETDEWEB)

Vermeulen, Frouke, E-mail: frouke.vermeulen@ua.ac.b [Ecophysiology, Biochemistry and Toxicology Group (U7), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van den Brink, Nico W., E-mail: nico.vandenbrink@wur.n [Alterra, Wageningen UR, Box 47, NL6700AA Wageningen (Netherlands); D' Have, Helga [Ecophysiology, Biochemistry and Toxicology Group (U7), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Mubiana, Valentine K., E-mail: kayawe.mubiana@ua.ac.b [Ecophysiology, Biochemistry and Toxicology Group (U7), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Blust, Ronny, E-mail: ronny.blust@ua.ac.b [Ecophysiology, Biochemistry and Toxicology Group (U7), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Bervoets, Lieven, E-mail: lieven.bervoets@ua.ac.b [Ecophysiology, Biochemistry and Toxicology Group (U7), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); De Coen, Wim, E-mail: wim.decoen@ua.ac.b [Ecophysiology, Biochemistry and Toxicology Group (U7), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

2009-11-15

The present study investigated the contribution of environmental factors to the accumulation of As, Cd, Cu, Pb and Zn in earthworms, beetles and woodlice, and framed within an exposure assessment of the European hedgehog. Soil and invertebrate samples were collected in three distinct habitat types. Results showed habitat-specific differences in soil and invertebrate metal concentrations and bioaccumulation factors when normalized to soil metal concentration. Further multiple regression analysis showed residual variability (habitat differences) in bioaccumulation that could not be fully explained by differences in soil metal contamination, pH or organic carbon (OC). Therefore, the study demonstrated that in bioaccumulation studies involving terrestrial invertebrates or in risk assessment of metals, it is not sufficient to differentiate habitat types on general soil characteristics such as pH and/or OC alone. Furthermore, simple generic soil risk assessments for Cd and Cu showed that risk characterization was more accurate when performed in a habitat-specific way. - Our study provided essential insights into habitat-specific accumulation patterns with respect to factors influencing metal bioaccumulation, BAFs, and site-specific risk assessment.

Sterilization affects soil organic matter chemistry and bioaccumulation of spiked p,p'-DDE and anthracene by earthworms

Energy Technology Data Exchange (ETDEWEB)

Kelsey, Jason W., E-mail: kelsey@muhlenberg.ed [Program in Environmental Science and Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, PA 18104 (United States); Slizovskiy, Ilya B.; Peters, Richard D.; Melnick, Adam M. [Program in Environmental Science and Department of Chemistry, Muhlenberg College, 2400 Chew Street, Allentown, PA 18104 (United States)

2010-06-15

Laboratory experiments were conducted to assess the effects of soil sterilization on the bioavailability of spiked p,p'-DDE and anthracene to the earthworms Eisenia fetida and Lumbricus terrestris. Physical and chemical changes to soil organic matter (SOM) induced by sterilization were also studied. Uptake of both compounds added after soil was autoclaved or gamma irradiated increased for E. fetida. Sterilization had no effect on bioaccumulation of p,p'-DDE by L. terrestris, and anthracene uptake increased only in gamma-irradiated soils. Analyses by FT-IR and DSC indicate sterilization alters SOM chemistry and may reduce pollutant sorption. Chemical changes to SOM were tentatively linked to changes in bioaccumulation, although the effects were compound and species specific. Artifacts produced by sterilization could lead to inaccurate risk assessments of contaminated sites if assumptions derived from studies carried out in sterilized soil are used. Ultimately, knowledge of SOM chemistry could aid predictions of bioaccumulation of organic pollutants. - Soil sterilization affects soil organic matter chemistry and pollutant bioaccumulation.

Methylmercury bioaccumulation in invertebrates of boreal streams in Norway: Effects of aqueous methylmercury and diet retention

International Nuclear Information System (INIS)

Wit, Heleen A. de; Kainz, Martin J.; Lindholm, Markus

2012-01-01

Transfer of aqueous methylmercury (MeHg) to primary consumers in aquatic foodwebs is poorly understood despite its importance for bioaccumulation of MeHg. We studied bioaccumulation of MeHg in simple aquatic food chains of two humic boreal streams in relation to streamwater chemistry, food web characteristics and dietary fatty acid (FA) biomarkers. Transfer of aqueous MeHg into primary consumers was similar in both streams, resulting in higher MeHg in consumers in the MeHg-rich stream. Trophic enrichment of MeHg and dietary retention of FA biomarkers was the same in both streams, suggesting that exposure to aqueous MeHg at the base of the food chain determined levels of MeHg in biota. In addition, contents of dietary biomarkers suggested that ingestion of algae reduced MeHg bioaccumulation, while ingestion of bacteria stimulated MeHg uptake. Dietary uptake of bacteria could thus be an important pathway for MeHg-transfer at the bottom of food chains in humic streams. - Highlights: ► We examined MeHg bioaccumulation in simple food chains in two boreal streams. ► Higher MeHg in invertebrates was associated with higher aqueous MeHg. ► Dietary biomarkers showed that consumers in both streams accessed similar food sources. ► We concluded at exposure to aqueous MeHg determined bioaccumulation of MeHg. ► Seasonal variation in MeHg in biota could be related to diet using dietary biomarkers. - Exposure to aqueous methylmercury at the base of the food chain in boreal streams determines mercury in aquatic biota at higher trophic levels.

Bioaccumulation and retention kinetics of cadmium in the freshwater decapod Macrobrachium australiense

Energy Technology Data Exchange (ETDEWEB)

Cresswell, Tom, E-mail: tom.cresswell@ansto.gov.au [Centre for Environmental Contaminants Research, CSIRO Land and Water, Locked Bag 2007, Kirrawee, NSW 2232 (Australia); School of Applied Sciences, RMIT University, Plenty Road, Bundoora, VIC 3083 (Australia); Simpson, Stuart L. [School of Applied Sciences, RMIT University, Plenty Road, Bundoora, VIC 3083 (Australia); Smith, Ross E.W. [Hydrobiology, Lang Parade, Auchenflower, QLD 4066 (Australia); Nugegoda, Dayanthi [School of Applied Sciences, RMIT University, Plenty Road, Bundoora, VIC 3083 (Australia); Mazumder, Debashish [Institute for Environmental Research, ANSTO, Locked Bag 2001, Kirrawee, NSW 2232 (Australia); Twining, John [Austral Radioecology, Oyster Bay, NSW, 2225 (Australia)

2014-03-01

Highlights: • Sources and mechanisms of Cd bioaccumulation were examined using radiotracers. • Macrobrachium australiense readily accumulated cadmium from the dissolved phase. • Assimilation efficiencies were comparable for sediment and algae. • A biokinetic model predicted ingestion accounted for majority of bioaccumulated Cd. - Abstract: The potential sources and mechanisms of cadmium bioaccumulation by the native freshwater decapods Macrobrachium species in the waters of the highly turbid Strickland River in Papua New Guinea were examined using {sup 109}Cd-labelled water and food sources and the Australian species Macrobrachium australiense as a surrogate. Synthetic river water was spiked with environmentally relevant concentrations of cadmium and animals were exposed for 7 days with daily renewal of test solutions. Dietary assimilation of cadmium was assessed through pulse-chase experiments where prawns were fed separately {sup 109}Cd-labelled fine sediment, filamentous algae and carrion (represented by cephalothorax tissue of water-exposed prawns). M. australiense readily accumulated cadmium from the dissolved phase and the uptake rate increased linearly with increasing exposure concentration. A cadmium uptake rate constant of 0.10 ± 0.05 L/g/d was determined in synthetic river water. During depuration following exposure to dissolved cadmium, efflux rates were low (0.9 ± 5%/d) and were not dependent on exposure concentration. Assimilation efficiencies of dietary sources were comparable for sediment and algae (48–51%), but lower for carrion (28 ± 5%) and efflux rates were low (0.2–2.6%/d) demonstrating that cadmium was well retained by M. australiense. A biokinetic model of cadmium accumulation by M. australiense predicted that for exposures to environmentally relevant cadmium concentrations in the Strickland River, uptake from ingestion of fine sediment and carrion would be the predominant sources of cadmium to the organism. The model predicted

Influence of body size on Cu bioaccumulation in zebra mussels Dreissena polymorpha exposed to different sources of particle-associated Cu.

Science.gov (United States)

Zhong, Huan; Kraemer, Lisa; Evans, Douglas

2013-10-15

Size of organisms is critical in controlling metal bioavailability and bioaccumulation, while mechanisms of size-related metal bioaccumulation are not fully understood. To investigate the influences of different sources of particle-associated Cu on body size-related Cu bioavailability and bioaccumulation, zebra mussels (Dreissena polymorpha) of different sizes were exposed to stable Cu isotope ((65)Cu) spiked algae (Chlorella vulgaris) or sediments in the laboratory and the Cu tissue concentration-size relationships were compared with that in unexposed mussels. Copper tissue concentrations decreased with mussel size (tissue or shell dry weight) in both unexposed and algal-exposed mussels with similar decreasing patterns, but were independent of size in sediment-exposed mussels. Furthermore, the relative contribution of Cu uptake from algae (65-91%) to Cu bioaccumulation is always higher than that from sediments (9-35%), possibly due to the higher bioavailability of algal-Cu. Therefore, the size-related ingestion of algae could be more important in influencing the size-related variations in Cu bioaccumulation. However, the relative contribution of sediment-Cu to Cu bioaccumulation increased with body size and thus sediment ingestion may also affect the size-related Cu variations in larger mussels (tissue weight >7.5mg). This study highlights the importance of considering exposure pathways in normalization of metal concentration variation when using bivalves as biomonitors. Copyright © 2013 Elsevier B.V. All rights reserved.

Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms

Science.gov (United States)

The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) capped silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) and titanium dioxide (TiO2) NPs in marine organisms via marine sediment exposure were investigated. Results from 7-d sedimen...

Study of heavy metals bioaccumulation in the process of ...

African Journals Online (AJOL)

Jane

2011-07-18

Jul 18, 2011 ... The bioaccumulation of heavy metals (Cd, Zn, Ni, Pb and Cr) and the relationship between them was investigated on ... this elements in 14 days) exposure, the metal accumulation was measured using atomic absorption spectroscopy. ... sed to the point that it endangers human life in some areas, and the ...

Structural changes in response to bioaccumulation of iron and mercury in Chromolaena odorata (L.) King & Robins.

Science.gov (United States)

Swapna, K S; Salim, Nabeesa; Chandra, Ratheesh; Puthur, Jos T

2015-09-01

A comparative study was designed to elucidate the effect of iron and mercury on the morphological and anatomical changes as well as bioaccumulation potential in Chromolaena odorata. Plants were grown in half-strength Hoagland nutrient medium artificially contaminated with known quantities of HgCl2 (15 μM) and FeCl3 (1000 μM). Bioaccumulation of Hg and Fe was maximum in the root, and comparatively reduced bioaccumulation was recorded in the stem and leaves. Microscopic studies on morphology and anatomy revealed development of trichomes and lenticels on the stem and modified trichomes on leaves. Localized deposits of stained masses in various internal parts of the root, stem and leaf also were observed. Differential adaptation/strategy of C. odorata to attain tolerance towards Hg and Fe and phytoremediation potential of the plant is discussed.

A comparison of PCB bioaccumulation factors between an arctic and a temperate marine food web.

Science.gov (United States)

Sobek, Anna; McLachlan, Michael S; Borgå, Katrine; Asplund, Lillemor; Lundstedt-Enkel, Katrin; Polder, Anuschka; Gustafsson, Orjan

2010-06-01

To test how environmental conditions in the Arctic and the resulting ecological adaptations affect accumulation of persistent organic pollutants (POPs) in the marine food web, bioaccumulation of four polychlorinated biphenyls (PCBs) in an arctic (Barents Sea 77 degrees N-82 degrees N) and a temperate marine (Baltic Sea 54 degrees N-62 degrees N) food web were compared. Three different trophic levels were studied (zooplankton, fish, and seal), representing the span from first-level consumer to top predator. Previously published high-quality data on PCB water concentrations in the two areas were used for calculation of bioaccumulation factors (BAF). BAF was calculated as the ratio of the PCB concentration in the organism ([PCB](org); pg/kg lipid) to the dissolved water concentration (C(w); pg/L). The BAF(Arctic):BAF(Temperate) ratios were above 1 for all four PCB congeners in zooplankton (6.4-13.8) and planktivorous fish (2.9-5.0)), whereas the ratios were below 1 in seal. The mean ratio between arctic and temperate BAFs for all trophic levels and congeners (BAF(Arcti):BAF(Temperate)) was 4.8. When the data were corrected for the seawater temperature difference between the two ecosystems, the ratio was 2.0. We conclude that bioaccumulation differences caused by ecological or physiological adaptations of organisms between the two ecosystems were well within a water concentration variability of 50%. Further, our data support the hypothesis that lower seawater temperature lead to a thermodynamically favoured passive partitioning to organic matrices and thus elevated ambient BAFs in the Arctic compared to the Baltic Sea. This would imply that bioaccumulation in the Arctic may be described in the same way as bioaccumulation in temperate regions, e.g. by the use of mechanistic models parameterised for the Arctic. Copyright (c) 2010. Published by Elsevier B.V.

A comparison of PCB bioaccumulation factors between an arctic and a temperate marine food web

International Nuclear Information System (INIS)

Sobek, Anna; McLachlan, Michael S.; Borga, Katrine; Asplund, Lillemor; Lundstedt-Enkel, Katrin; Polder, Anuschka; Gustafsson, Orjan

2010-01-01

To test how environmental conditions in the Arctic and the resulting ecological adaptations affect accumulation of persistent organic pollutants (POPs) in the marine food web, bioaccumulation of four polychlorinated biphenyls (PCBs) in an arctic (Barents Sea 77 o N-82 o N) and a temperate marine (Baltic Sea 54 o N-62 o N) food web were compared. Three different trophic levels were studied (zooplankton, fish, and seal), representing the span from first-level consumer to top predator. Previously published high-quality data on PCB water concentrations in the two areas were used for calculation of bioaccumulation factors (BAF). BAF was calculated as the ratio of the PCB concentration in the organism ([PCB] org ; pg/kg lipid) to the dissolved water concentration (C w ; pg/L). The BAF Arctic :BAF Temperate ratios were above 1 for all four PCB congeners in zooplankton (6.4-13.8) and planktivorous fish (2.9-5.0)), whereas the ratios were below 1 in seal. The mean ratio between arctic and temperate BAFs for all trophic levels and congeners (BAF Arcti :BAF Temperate ) was 4.8. When the data were corrected for the seawater temperature difference between the two ecosystems, the ratio was 2.0. We conclude that bioaccumulation differences caused by ecological or physiological adaptations of organisms between the two ecosystems were well within a water concentration variability of 50%. Further, our data support the hypothesis that lower seawater temperature lead to a thermodynamically favoured passive partitioning to organic matrices and thus elevated ambient BAFs in the Arctic compared to the Baltic Sea. This would imply that bioaccumulation in the Arctic may be described in the same way as bioaccumulation in temperate regions, e.g. by the use of mechanistic models parameterised for the Arctic.

Hydroxyl migration disorders the surface structure of hydroxyapatite nanoparticles

Science.gov (United States)

Cheng, Xiajie; Wu, Hong; Zhang, Li; Ma, Xingtao; Zhang, Xingdong; Yang, Mingli

2017-09-01

The surface structure of nano-hydroxyapatite (HAP) was investigated using a combined simulated annealing and molecular dynamics method. The stationary structures of nano-HAP with 4-7 nm in diameter and annealed under different temperatures were analyzed in terms of pair distribution function, structural factor, mean square displacement and atomic coordination number. The particles possess different structures from bulk crystal. A clear radial change in their atomic arrangements was noted. From core to surface the structures change from ordered to disordered. A three-shell model was proposed to describe the structure evolution of nano-HAP. Atoms in the core zone keep their arrangements as in crystal, while atoms in the surface shell are in short-range order and long-range disorder, adopting a typically amorphous structure. Atoms in the middle shell have small displacements and/or deflections but basically retain their original locations as in crystal. The disordered shell is about 1 nm in thickness, in agreement with experimental observations. The disordering mainly stems from hydroxyl migration during which hydroxyls move to the surface and bond with the exposed Ca ions, and their left vacancies bring about a rearrangement of nearby atoms. The disordering is to some extent different for particles unannealed under different temperatures, resulting from fewer number of migrated hydroxyls at lower temperatures. Particles with different sizes have similar surface structures, and their surface energy decreases with increasing size. Moreover, the surface energy is reduced by hydroxyl migration because the exposed Ca ions on the surface are ionically bonded with the migrated hydroxyls. Our calculations proposed a new structure model for nano-HAP, which indicates a surface structure with activities different from those without surface reorganization. This is particularly interesting because most bioactivities of biomaterials are dominated by their surface activity.

Evaluation of PCB bioaccumulation by Lumbriculus variegatus in field-collected sediments

Science.gov (United States)

Sediment bioaccumulation tests with Lumbriculus variegatus were performed on polychlorinated biphenyl (PCBs) contaminated sediment samples from the Hudson, Grasse, and Fox Rivers Superfund sites with concurrent measurement of PCB concentrations in sediment interstitial water. Th...

Arsenic bioaccumulation in a marine juvenile fish Terapon jarbua

International Nuclear Information System (INIS)

Zhang Wei; Huang Liangmin; Wang Wenxiong

2011-01-01

Highlights: Radiotracer technique was used to quantify the biokinetics of As(V) in a marine fish. As(V) had a low bioavailability to Terapon jarbua. Dietary assimilation of As was only 3.1–7.4% for fish fed with different preys. Dietary uptake could be the primary route for As bioaccumulation in fish. - Abstract: Arsenic (As) is a ubiquitous toxic metalloid that is causing widespread public concern. Recent measurements have indicated that some marine fish in China might be seriously contaminated with As. Yet the biokinetics and bioaccumulation pathway of As in fish remain little understood. In this study, we employed a radiotracer technique to quantify the dissolved uptake, dietary assimilation and subsequent efflux of As(V) in a marine predatory fish, Terapon jarbua. The dissolved uptake of As showed a linear pattern over a range of dissolved concentrations from 0.5 to 50 μg L −1 , with a corresponding uptake rate constant of 0.0015 L g −1 d −1 . The assimilation efficiencies (AEs) of dietary As were only 3.1–7.4% for fish fed with copepods, clams, prey fish, or artificial diets, and were much lower than the As that entered the trophically available metal fraction in the prey. The dietary AEs were independent of the As(V) concentrations in the artificial diets. The efflux rate constant of As in fish following the dietary exposure was 0.03 d −1 . Modeling calculations showed that dietary uptake could be the primary route for As bioaccumulation in fish, and the corresponding contributions of waterborne and dietary uptakes were related to the bioconcentration factor (BCF) of the prey and the ingestion rate of fish. This study demonstrates that As(V) has a low bioavailability to T. jarbua.

Equilibrium sampling to determine the thermodynamic potential for bioaccumulation of persistent organic pollutants from sediment.

Science.gov (United States)

Jahnke, Annika; MacLeod, Matthew; Wickström, Håkan; Mayer, Philipp

2014-10-07

Equilibrium partitioning (EqP) theory is currently the most widely used approach for linking sediment pollution by persistent hydrophobic organic chemicals to bioaccumulation. Most applications of the EqP approach assume (I) a generic relationship between organic carbon-normalized chemical concentrations in sediments and lipid-normalized concentrations in biota and (II) that bioaccumulation does not induce levels exceeding those expected from equilibrium partitioning. Here, we demonstrate that assumption I can be obviated by equilibrating a silicone sampler with chemicals in sediment, measuring chemical concentrations in the silicone, and applying lipid/silicone partition ratios to yield concentrations in lipid at thermodynamic equilibrium with the sediment (CLip⇌Sed). Furthermore, we evaluated the validity of assumption II by comparing CLip⇌Sed of selected persistent, bioaccumulative and toxic pollutants (polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB)) to lipid-normalized concentrations for a range of biota from a Swedish background lake. PCBs in duck mussels, roach, eel, pikeperch, perch and pike were mostly below the equilibrium partitioning level relative to the sediment, i.e., lipid-normalized concentrations were ≤CLip⇌Sed, whereas HCB was near equilibrium between biota and sediment. Equilibrium sampling allows straightforward, sensitive and precise measurement of CLip⇌Sed. We propose CLip⇌Sed as a metric of the thermodynamic potential for bioaccumulation of persistent organic chemicals from sediment useful to prioritize management actions to remediate contaminated sites.

Testosterone 15β-hydroxylation by solvent tolerant Pseudomonas putida S12

NARCIS (Netherlands)

Ruijssenaars, H.J.; Sperling, E.M.G.M.; Wiegerinck, P.H.G.; Brands, F.T.L.; Wery, J.; Bont, J.A.M.de

2007-01-01

A steroid 15β-hydroxylating whole-cell solvent tolerant biocatalyst was constructed by expressing the Bacillus megaterium steroid hydroxylase CYP106A2 in the solvent tolerant Pseudomonas putida S12. Testosterone hydroxylation was improved by a factor 16 by co-expressing Fer, a putative Fe-S protein

Differential effects of collagen prolyl 3-hydroxylation on skeletal tissues.

Directory of Open Access Journals (Sweden)

Erica P Homan

2014-01-01

Full Text Available Mutations in the genes encoding cartilage associated protein (CRTAP and prolyl 3-hydroxylase 1 (P3H1 encoded by LEPRE1 were the first identified causes of recessive Osteogenesis Imperfecta (OI. These proteins, together with cyclophilin B (encoded by PPIB, form a complex that 3-hydroxylates a single proline residue on the α1(I chain (Pro986 and has cis/trans isomerase (PPIase activity essential for proper collagen folding. Recent data suggest that prolyl 3-hydroxylation of Pro986 is not required for the structural stability of collagen; however, the absence of this post-translational modification may disrupt protein-protein interactions integral for proper collagen folding and lead to collagen over-modification. P3H1 and CRTAP stabilize each other and absence of one results in degradation of the other. Hence, hypomorphic or loss of function mutations of either gene cause loss of the whole complex and its associated functions. The relative contribution of losing this complex's 3-hydroxylation versus PPIase and collagen chaperone activities to the phenotype of recessive OI is unknown. To distinguish between these functions, we generated knock-in mice carrying a single amino acid substitution in the catalytic site of P3h1 (Lepre1(H662A . This substitution abolished P3h1 activity but retained ability to form a complex with Crtap and thus the collagen chaperone function. Knock-in mice showed absence of prolyl 3-hydroxylation at Pro986 of the α1(I and α1(II collagen chains but no significant over-modification at other collagen residues. They were normal in appearance, had no growth defects and normal cartilage growth plate histology but showed decreased trabecular bone mass. This new mouse model recapitulates elements of the bone phenotype of OI but not the cartilage and growth phenotypes caused by loss of the prolyl 3-hydroxylation complex. Our observations suggest differential tissue consequences due to selective inactivation of P3H1 hydroxylase

A method for improving predictive modeling by taking into account lag time: Example of selenium bioaccumulation in a flowing system

Energy Technology Data Exchange (ETDEWEB)

Beckon, William N., E-mail: William_Beckon@fws.gov

2016-07-15

Highlights: • A method for estimating response time in cause-effect relationships is demonstrated. • Predictive modeling is appreciably improved by taking into account this lag time. • Bioaccumulation lag is greater for organisms at higher trophic levels. • This methodology may be widely applicable in disparate disciplines. - Abstract: For bioaccumulative substances, efforts to predict concentrations in organisms at upper trophic levels, based on measurements of environmental exposure, have been confounded by the appreciable but hitherto unknown amount of time it may take for bioaccumulation to occur through various pathways and across several trophic transfers. The study summarized here demonstrates an objective method of estimating this lag time by testing a large array of potential lag times for selenium bioaccumulation, selecting the lag that provides the best regression between environmental exposure (concentration in ambient water) and concentration in the tissue of the target organism. Bioaccumulation lag is generally greater for organisms at higher trophic levels, reaching times of more than a year in piscivorous fish. Predictive modeling of bioaccumulation is improved appreciably by taking into account this lag. More generally, the method demonstrated here may improve the accuracy of predictive modeling in a wide variety of other cause-effect relationships in which lag time is substantial but inadequately known, in disciplines as diverse as climatology (e.g., the effect of greenhouse gases on sea levels) and economics (e.g., the effects of fiscal stimulus on employment).

A method for improving predictive modeling by taking into account lag time: Example of selenium bioaccumulation in a flowing system

International Nuclear Information System (INIS)

Beckon, William N.

2016-01-01

Highlights: • A method for estimating response time in cause-effect relationships is demonstrated. • Predictive modeling is appreciably improved by taking into account this lag time. • Bioaccumulation lag is greater for organisms at higher trophic levels. • This methodology may be widely applicable in disparate disciplines. - Abstract: For bioaccumulative substances, efforts to predict concentrations in organisms at upper trophic levels, based on measurements of environmental exposure, have been confounded by the appreciable but hitherto unknown amount of time it may take for bioaccumulation to occur through various pathways and across several trophic transfers. The study summarized here demonstrates an objective method of estimating this lag time by testing a large array of potential lag times for selenium bioaccumulation, selecting the lag that provides the best regression between environmental exposure (concentration in ambient water) and concentration in the tissue of the target organism. Bioaccumulation lag is generally greater for organisms at higher trophic levels, reaching times of more than a year in piscivorous fish. Predictive modeling of bioaccumulation is improved appreciably by taking into account this lag. More generally, the method demonstrated here may improve the accuracy of predictive modeling in a wide variety of other cause-effect relationships in which lag time is substantial but inadequately known, in disciplines as diverse as climatology (e.g., the effect of greenhouse gases on sea levels) and economics (e.g., the effects of fiscal stimulus on employment).

Capability of pentavalent arsenic bioaccumulation and biovolatilization of three fungal strains under laboratory conditions

Energy Technology Data Exchange (ETDEWEB)

Su, Shiming; Li, Lianfang; Bai, Lingyu; Zhang, Yanrong [Key Laboratory of Agro-Environment and Climate Change, Chinese Academy of Agricultural Sciences, Beijing (China); Jiang, Xiliang [Key Laboratory for Biological Control, Chinese Academy of Agricultural Sciences, Beijing (China); Zeng, Xibai

2010-03-15

In order to control and remediate arsenic (As) contaminated soil, sediment or water, fungi are used to investigate their potential accumulation and volatilization of As. In this study, after cultivation for 2 days, the dry weights of mycelia for Trichoderma asperellum, Fusarium oxysporum and Penicillium janthinellum all show an increased trend when the As(V) concentration ranges from 0-50, 0-50, 0-80 mg/L, respectively. When the culture system is loaded with 2500 {mu}g As(V), which represents 50 mg/L As, and cultivated for 5 days, P. janthinellum presents the highest efficiency of 87.0 {mu}g/g for As bioaccumulation, and the order of the efficiency for As bioaccumulation is P. janthinellum > T. asperellum > F. oxysporum. However, the order of the amount of volatilized As is F. oxysporum > P. janthinellum > T. asperellum, and the highest amount of volatilized As is observed for F. oxysporum at 181.0 {mu}g. Thus, the ability of As bioaccumulation and biovolatilization for T. asperellum and P. janthinellum is reported for the first time in this study. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

The bioaccumulation and toxicity induced by gold nanoparticles in ...

African Journals Online (AJOL)

It is essential to characterize the bioaccumulation and toxicity of gold nanoparticles (GNPs) in blood prior to using them in drug delivery, diagnostics, and treatment. The aim of the present study was to evaluate the blood absorbance spectra after intraperitoneal administration of 50 μl of 10, 20, and 50 nm GNPs in rat for ...

Presence of hydrogen peroxide, a source of hydroxyl radicals, in acid electrolyzed water.

Directory of Open Access Journals (Sweden)

Takayuki Mokudai

Full Text Available BACKGROUND: Acid electrolyzed water (AEW, which is produced through the electrolysis of dilute sodium chloride (NaCl or potassium chloride solution, is used as a disinfectant in various fields because of its potent antimicrobial activity. The hydroxyl radical, an oxygen radical species, is often suggested as a putative active ingredient for AEW antimicrobial activity. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study is to detect hydroxyl radicals in AEW. The hydroxyl radicals in AEW prepared under different conditions were determined using an electron spin resonance (ESR technique. A signal from 5,5-dimethyl-1-pyrroline N-oxide (DMPO-OH, an adduct of DMPO and the hydroxyl radical, was detected in AEW prepared by double or triple electrolyses of 1% NaCl but not of 0.1% NaCl solution. Then the presence of hydrogen peroxide as a proposed source of hydroxyl radicals was examined using a combination of ESR and a Fenton reaction. The DMPO-OH signal was clearly detected, even in AEW prepared by single electrolysis of 0.1% NaCl solution, when ferrous sulfate was added to induce a Fenton reaction, indicating the presence of hydrogen peroxide in the AEW. Since sodium formate, a hydroxyl radical scavenger, did not affect the bactericidal activity of AEW, it is concluded that the radical is unlikely to contribute to the antimicrobial activity of AEW, although a small amount of the radical is produced from hydrogen peroxide. Dimethyl sulfoxide, the other hydroxyl radical scavenger used in the present study, canceled the bactericidal activity of AEW, accompanied by complete depletion of free available chlorine, suggesting that hypochlorous acid is probably a major contributor to the antimicrobial activity. CONCLUSIONS: It is strongly suggested that although hydrogen peroxide is present in AEW as a source of hydroxyl radicals, the antimicrobial activity of AEW does not depend on these radicals.

Reviewing the serotonin reuptake inhibitors (SSRIs) footprint in the aquatic biota: Uptake, bioaccumulation and ecotoxicology

International Nuclear Information System (INIS)

a Comba, 3000-548 Coimbra (Portugal))" data-affiliation=" (REQUIMTE, Group of Bromatology, Pharmacognosy and Analytical Sciences, Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Sta Comba, 3000-548 Coimbra (Portugal))" >Silva, Liliana J.G.; a Comba, 3000-548 Coimbra (Portugal))" data-affiliation=" (REQUIMTE, Group of Bromatology, Pharmacognosy and Analytical Sciences, Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Sta Comba, 3000-548 Coimbra (Portugal))" >Pereira, André a Comba, 3000-548 Coimbra (Portugal))" data-affiliation=" (REQUIMTE, Group of Bromatology, Pharmacognosy and Analytical Sciences, Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Sta Comba, 3000-548 Coimbra (Portugal))" >M.P.T.; Meisel, Leonor M.; a Comba, 3000-548 Coimbra (Portugal))" data-affiliation=" (REQUIMTE, Group of Bromatology, Pharmacognosy and Analytical Sciences, Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Sta Comba, 3000-548 Coimbra (Portugal))" >Lino, Celeste M.; a Comba, 3000-548 Coimbra (Portugal))" data-affiliation=" (REQUIMTE, Group of Bromatology, Pharmacognosy and Analytical Sciences, Faculty of Pharmacy, University of Coimbra, Polo III, Azinhaga de Sta Comba, 3000-548 Coimbra (Portugal))" >Pena, Angelina

2015-01-01

Selective serotonin re-uptake inhibitors (SSRIs) antidepressants are amongst the most prescribed pharmaceutical active substances throughout the world. Their presence, already described in different environmental compartments such as wastewaters, surface, ground and drinking waters, and sediments, and their remarkable effects on non-target organisms justify the growing concern about these emerging environmental pollutants. A comprehensive review of the literature data with focus on their footprint in the aquatic biota, namely their uptake, bioaccumulation and both acute and chronic ecotoxicology is presented. Long-term multigenerational exposure studies, at environmental relevant concentrations and in mixtures of related compounds, such as oestrogenic endocrine disruptors, continue to be sparse and are imperative to better know their environmental impact. - Highlights: • Current knowledge of uptake and bioaccumulation of SSRIs. • Ecotoxicology and effects of SSRIs in the aquatic biota. • Identification of existing knowledge gaps. - A comprehensive review focussing SSRIs antidepressants footprint in the aquatic biota, namely their uptake, bioaccumulation, and both acute and chronic ecotoxicology is presented

Enantiomerization and enantioselective bioaccumulation of metalaxyl in Tenebrio molitor larvae.

Science.gov (United States)

Gao, Yongxin; Wang, Huili; Qin, Fang; Xu, Peng; Lv, Xiaotian; Li, Jianzhong; Guo, Baoyuan

2014-02-01

The enantiomerization and enantioselective bioaccumulation of metalaxyl by a single dose of exposure to Tenebrio molitor larvae under laboratory condition were studied by high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS) based on a ChiralcelOD-3R [cellulosetris-tris-(3, 5-dichlorophenyl-carbamate)] column. Exposure of enantiopure R-metalaxyl and S-metalaxyl in Tenebrio molitor larvae exhibited significant enantiomerization, with formation of the R enantiomers from the S enantiomers, and vice versa, which might be attributed to the chiral pesticide catalyzed by a certain enzyme in Tenebrio molitor larvae. Enantiomerization was not observed in wheat bran during the period of 21 d. In addition, bioaccumulation of rac-metalaxyl in Tenebrio molitor larvae was enantioselective with a preferential accumulation of S-metalaxyl. These results showed that enantioselectivity was caused not only by actual degradation and metabolism but also by enantiomerization, which was an important process in the environmental fate and behavior of metalaxyl enantiomers. Copyright © 2013 Wiley Periodicals, Inc.

Variation in bioaccumulation of persistent organic pollutants based on octanol-air partitioning: Influence of respiratory elimination in marine species.

Science.gov (United States)

Moses, Sara K; Harley, John R; Lieske, Camilla L; Muir, Derek C G; Whiting, Alex V; O'Hara, Todd M

2015-11-15

Risk assessments of persistent organic pollutants (POPs) are often based on octanol-water (KOW) partitioning dynamics and may not adequately reflect bioaccumulation in air-breathing organisms. It has been suggested that compounds with low KOW and high octanol-air partitioning (KOA) coefficients have the potential to bioaccumulate in air-breathing organisms, including marine mammals. Here we evaluate differences in concentrations of POPs for two trophically matched Arctic species, spotted seal (Phoca largha) and sheefish (Stenodus leucichthys). We compared concentrations of 108 POPs in matched tissues (liver and muscle) across three ranges of KOW. We found a significant positive correlation between POP concentration and log KOA in spotted seal tissues for low log KOW compounds (log KOW <5.5, p<0.05). This provides further evidence for empirical models and observed bioaccumulation patterns in air-breathing organisms, and highlights the potential for bioaccumulation of these compounds in Arctic marine mammals. Copyright © 2015 Elsevier Ltd. All rights reserved.

The mismatch between bioaccumulation in field and laboratory environments: Interpreting the differences for metals in benthic bivalves

International Nuclear Information System (INIS)

Belzunce-Segarra, Maria J.; Simpson, Stuart L.; Amato, Elvio D.; Spadaro, David A.; Hamilton, Ian L.; Jarolimek, Chad V.; Jolley, Dianne F.

2015-01-01

Laboratory-based bioaccumulation and toxicity bioassays are frequently used to predict the ecological risk of contaminated sediments in the field. This study investigates the bioassay conditions most relevant to achieving environmentally relevant field exposures. An identical series of metal-contaminated marine sediments were deployed in the field and laboratory over 31 days. Changes in metal concentrations and partitioning in both sediments and waters were used to interpret differences in metal exposure and bioaccumulation to the benthic bivalve Tellina deltoidalis. Loss of resuspended sediments and deposition of suspended particulate matter from the overlying water resulted in the concentrations of Cu, Pb and Zn (major contaminants) becoming lower in the 1-cm surface layer of field-deployed sediments. Lower exchange rates of overlying waters in the laboratory resulted in higher dissolved metal exposures. The prediction of metal bioaccumulation by the bivalves in field and laboratory was improved by considering the metal partitioning within the surface sediments. - Highlights: • Particulate metals are the dominant metal exposure route in laboratory and field tests (87). • There is an over-representation of the dissolved metal exposure in the laboratory (81). • Laboratory bioassays result in higher bioaccumulation of major metals, Cu, Pb, Zn (82). • Differences in exposure must be considered for a proper sediment quality evaluation (83). • Traditional measurements are not sufficient to explain bioaccumulation results (79). - To improve the value of field- and laboratory-based sediment bioassays in ecological risk assessments, it is necessary to create exposure conditions that resemble those in the field

Functionalization of hydroxyl terminated polybutadiene with ...

Indian Academy of Sciences (India)

Administrator

The hydroxyl terminated polybutadiene (HTPB) used in this work was prepared by free radical polymerization using hydrogen peroxide as initiator and was received from HEMRL Pune, India, as a gift sample. The molecu- lar weight and polydispersity of the HTPB was deter- mined by using gel permeable chromatography ...

Agricultural wetlands as potential hotspots for mercury bioaccumulation: Experimental evidence using caged fish

Science.gov (United States)

Ackerman, Joshua T.; Eagles-Smith, Collin A.

2010-01-01

Wetlands provide numerous ecosystem services, but also can be sources of methylmercury (MeHg) production and export. Rice agricultural wetlands in particular may be important sites for MeHg bioaccumulation due to their worldwide ubiquity, periodic flooding schedules, and high use by wildlife. We assessed MeHg bioaccumulation within agricultural and perennial wetlands common to California's Central Valley during summer, when the majority of wetland habitats are shallowly flooded rice fields. We introduced caged western mosquitofish (Gambusia affinis) within white rice (Oryza sativa), wild rice (Zizania palustris), and permanent wetlands at water inlets, centers, and outlets. Total mercury (THg) concentrations and body burdens in caged mosquitofish increased rapidly, exceeding baseline values at introduction by 135% to 1197% and 29% to 1566% among sites, respectively, after only 60 days. Mercury bioaccumulation in caged mosquitofish was greater in rice fields than in permanent wetlands, with THg concentrations at wetland outlets increasing by 12.1, 5.8, and 2.9 times over initial concentrations in white rice, wild rice, and permanent wetlands, respectively. In fact, mosquitofish caged at white rice outlets accumulated 721 ng Hg/fish in just 60 days. Mercury in wild mosquito fish and Mississippi silversides (Menidia audens) concurrently sampled at wetland outlets also were greater in white rice and wild rice than permanent wetlands. Within wetlands, THg concentrations and body burdens of both caged and wild fish increased from water inlets to outlets in white rice fields, and tended to not vary among sites in permanent wetlands. Fish THg concentrations in agricultural wetlands were high, exceeding 0.2 ??g/g ww in 82% of caged fish and 59% of wild fish. Our results indicate that shallowly flooded rice fields are potential hotspots for MeHg bioaccumulation and, due to their global prevalence, suggest that agricultural wetlands may be important contributors to Me

Assessment of Mercury Bioaccumulation in Zebra Cichlid (Cichlasoma Nigrofasciatum Exposed to Sublethal Concentrations of Permethrin

Directory of Open Access Journals (Sweden)

Mahdi Banaee

2014-12-01

Full Text Available Background: Aquatic ecosystems are frequently subjected to contamination by toxic heavy metals and pesticides, yet very little is known about the influence of pesticides on bioaccumulation of heavy metals in aquatic organisms. Mercury is a toxic metal with no known biological benefit to organisms. Bioavailability of mercury in aquatic environments depends on biological and non-biological parameters including other pollutants. Therefore, the objectives of this research were to determine the effects of permethrin on bioaccumulation of mercury in zebra cichlid. Methods: Acute toxicity (LC50 of permethrin and mercury chloride was evaluated by estimating mortality in Probit Model in SPSS (version 19.0 IBM. In sub-lethal toxicity, zebra cichlid (Cichlasoma nigrofasciatum was exposed to various concentrations of permethrin (0.0, 0.40, 0.80, 1.20 and 1.60 µg.L-1 combined with 20 µg.L-1 mercury chloride for 15 days. At the end of the experiment, mercury concentrations were measured using ICP-OES-Perkin elmer (optima 7300-DV. Results: 96 h LC50 values of permethrin and mercury for C. nigrofasciatum were calculated to be 17.55 µg.L-1 and 140.38 µg.L-1, respectively. Our results clearly showed that the bioaccumulation of mercury in the specimens increased with increasing concentrations of permethrin to 1.20 and 1.60 µg.L-1. Conclusion: Increasing the concentration of permethrin had synergistic effects on the bioaccumulation of mercury in fish.

Different modes of TiO2 uptake by Ceriodaphnia dubia: relevance to toxicity and bioaccumulation.

Science.gov (United States)

Dalai, Swayamprava; Iswarya, V; Bhuvaneshwari, M; Pakrashi, Sunandan; Chandrasekaran, N; Mukherjee, Amitava

2014-07-01

The extensive environmental exposure of engineered metal oxide nanoparticles (NPs) may result in their bioaccumulation in aquatic organisms leading to their biotransfer in a food chain through various routes in a freshwater ecosystem. The present study focuses on the possible modes of TiO2 NP trophic transfer to Ceriodaphnia dubia, in presence and/absence of its diet, Scenedesmus obliquus (primary producer). The acute exposure studies (48h) were designed to have daphnids exposed to (i) the free NPs, (ii) both the free and the algae-borne NPs; and (iii) only the algae-borne NPs in separate tests to understand the possible routes of NP transfer. The dietary uptake of TiO2 NPs (algae-borne) was found to be the primary route for NP biotransfer with ∼70% of total NP uptake. Interestingly, in a separate study it was noticed that the NPs coated with algal exudates were easily taken up by daphnids as compared to pristine NPs of same concentrations, leading to their higher bioaccumulation. A chronic toxicity study, where daphnids were exposed to both free and algae-borne NPs for 21 days was undertaken to comprehend the TiO2 NP effect on daphnia growth and reproduction upon chronic exposure and also the bioaccumulation potential. Both acute and chronic exposure studies suggested higher bioaccumulation of TiO2 in daphnids when the particles were less toxic to the diet (algae). Copyright © 2014 Elsevier B.V. All rights reserved.

Measurement of hydroxyl radical production in ultrasonic aqueous solutions by a novel chemiluminescence method.

Science.gov (United States)

Hu, Yufei; Zhang, Zhujun; Yang, Chunyan

2008-07-01

Measurement methods for ultrasonic fields are important for reasons of safety. The investigation of an ultrasonic field can be performed by detecting the yield of hydroxyl radicals resulting from ultrasonic cavitations. In this paper, a novel method is introduced for detecting hydroxyl radicals by a chemiluminescence (CL) reaction of luminol-hydrogen peroxide (H2O2)-K5[Cu(HIO6)2](DPC). The yield of hydroxyl radicals is calculated directly by the relative CL intensity according to the corresponding concentration of H2O2. This proposed CL method makes it possible to perform an in-line and real-time assay of hydroxyl radicals in an ultrasonic aqueous solution. With flow injection (FI) technology, this novel CL reaction is sensitive enough to detect ultra trace amounts of H2O2 with a limit of detection (3sigma) of 4.1 x 10(-11) mol L(-1). The influences of ultrasonic output power and ultrasonic treatment time on the yield of hydroxyl radicals by an ultrasound generator were also studied. The results indicate that the amount of hydroxyl radicals increases with the increase of ultrasonic output power (< or = 15 W mL(-1)). There is a linear relationship between the time of ultrasonic treatment and the yield of H2O2. The ultrasonic field of an ultrasonic cleaning baths has been measured by calculating the yield of hydroxyl radicals.

Acute toxicity and bio-accumulation of mercury and copper in ...

African Journals Online (AJOL)

The acute toxicity of Mercury and Copper on C. africanus and T. fuscatus and the bio-accumulation potentials of the metals were investigated in laboratory experiments employing standard bio–assay techniques. On the basis of LC50 values, both metals had similar magnitudes of toxicity against C. africanus. However ...

气相色谱-质谱法分析某阻燃剂生产厂周边淡水鱼中的多溴联苯醚及其累积特征%Determination of Polybrominated Diphenyl Ethers and Bioaccumulation in Freshwater Fish Surrounding a Flame Retardant Manufacturing Plant by Gas Chromatography-Mass Spectrometry

Institute of Scientific and Technical Information of China (English)

徐洁; 鲜啟鸣

2017-01-01

In recent years, the research on polybrominated diphenyl ethers (PBDEs) has been heavily concentrated in polluted areas, such as the developed areas of the electronic industry, electronic waste disposal arrears, and plastic materials production areas.Research on PBDEs surrounding a flame retardant manufacturing plant may contribute to a better comprehension of their bioaccumulation characteristics and environmental processes.Five species of fish were collected from a freshwater environment surrounding a PBDE technical mixtures manufacturing plant in Jiangsu Province.Concentrations of thirteen PBDE congeners were determined by Gas Chromatography-Mass Spectrometry (GC-MS).Results show that the average concentrations of ∑13PBDEs (BDE17, 28, 71, 47, 66, 100, 99, 85, 154, 153, 138, 183, 190) in muscle, liver and egg tissues are 34.5 ng/g.lip, 41.5 ng/g.lip and 18.2 ng/g.lip, respectively.Feeding and living habits as well as metabolic ability may influence the occurrence of PBDEs in fish in this area.BDE47 was the predominant compound in most fish samples, however, the fish in the present study have a higher proportion of hexa-and hepta-BDEs such as BDE153, BDE154 and BDE183 compared to the data reported in other studies, which is consistent with the octa-BDE technical mixtures (dominated by hexa-, hepta-and octa-BDEs) from the manufacturing plant near the river.The octa-BDE technical mixtures produced here, and the PBDE technical mixtures produced and used in other regions were carried in by upstream runoff and released into the environment, which were selectively bioaccumulated and metabolized by freshwater fish, resulting in the specific distribution of PBDE congeners in fish in this area.%近年来多溴联苯醚(PBDEs)的研究集中在电子行业发达地区、电子废物处置区、塑料制品生产区等重点污染区域.对阻燃剂生产厂周边PBDEs的研究有助于更好地理解PBDEs的累积特征和环境过程.本文�

Equilibrium Sampling to Determine the Thermodynamic Potential for Bioaccumulation of Persistent Organic Pollutants from Sediment

DEFF Research Database (Denmark)

Jahnke, Annika; MacLeod, Matthew; Wickström, Håkan

2014-01-01

Equilibrium partitioning (EqP) theory is currently the most widely used approach for linking sediment pollution by persistent hydrophobic organic chemicals to bioaccumulation. Most applications of the EqP approach assume (I) a generic relationship between organic carbon-normalized chemical...... chemical concentrations in the silicone, and applying lipid/silicone partition ratios to yield concentrations in lipid at thermodynamic equilibrium with the sediment (CLip⇌Sed). Furthermore, we evaluated the validity of assumption II by comparing CLip⇌Sed of selected persistent, bioaccumulative and toxic...... organic chemicals from sediment useful to prioritize management actions to remediate contaminated sites....

Mechanism of aromatic hydroxylation of lidocaine at a Pt electrode under acidic conditions

International Nuclear Information System (INIS)

Gul, Turan; Bischoff, Rainer; Permentier, Hjalmar P.

2017-01-01

Aromatic hydroxylation reactions, which are mainly catalyzed by cytochrome P450 (CYP) enzymes in vivo, are some of the most important reactions of Phase I metabolism, because insertion of a hydroxyl group into a lipophilic drug compound increases its hydrophilicity and prepares it for subsequent Phase II metabolic conjugation reactions as a prerequisite to excretion. Aromatic hydroxylation metabolites of pharmaceuticals may be obtained through various synthetic and enzymatic methods Electrochemical oxidation is an alternative with advantages in terms of mild reaction conditions and less hazardous chemicals. In the present study, we report that aromatic hydroxylation metabolites of lidocaine can be readily obtained electrochemically under aqueous acidic conditions at platinum electrodes. Our results show that the dominant N-dealkylation reaction can be suppressed by decreasing the solution pH below 0.5 resulting in selective 3-hydroxylidocaine, which is an in vivo metabolite of lidocaine. Experiments in 18 O labelled water indicated that water is the primary source of oxygen, while dissolved molecular oxygen contributes to a minor extent to the hydroxylation reaction.

The hydroxyl species and acid sites on diatomite surface: a combined IR and Raman study

Science.gov (United States)

Yuan, P.; Wu, D. Q.; He, H. P.; Lin, Z. Y.

2004-04-01

Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy of adsorbed pyridine molecules (Py-Raman) and in situ Py-IR have been used to investigate the hydroxyl species and acid sites on diatomite surfaces. The Lewis (L) and Brønsted (B) acid sites, and various hydroxyl species, including isolated hydroxyl groups, H-bonded hydroxyl groups and physically adsorbed water, are identified. The L acid sites in diatomite samples are resulted from the clay impurities, and the B acid sites are resulted from some moderate strength H-bonded hydroxyl groups. At room temperature, both of the isolated and H-bonded silanols associate with the physically adsorbed water by hydrogen bond. After calcination treatment, physically adsorbed water will be desorbed from the silanols, and the silanols will condense with the increase of temperature. Generally, the H-bonded silanols condense more easily than the isolated ones. The properties of surface hydroxyl species of diatomaceous silica are more similar to precipitated silica rather than fumed silica.

Bioaccumulation of heavy metals by freshwater algal species of Bhavnagar, Gujarat, India.

Science.gov (United States)

Jaiswar, Santial; Kazi, Mudassar Anisoddin; Mehta, Shailesh

2015-11-01

The present study investigated copper, cadmium, lead and zinc accumulation in algal species Oedogonium, Cladophora, Oscillatoria and Spirogyra from freshwater habitats of Bhavnagar, India. Eight different locations were periodically sampled during August 2009 to March 2011. The general trend of heavy metal concentrations in all the algal species in present study (except at few stations), were found to be in the following order: Zn > Cu > Pb > Cd. Highest accumulation of Cu was recorded in Oedogonium, while Cladophora showed highest accumulation of Pb signifying a good bioaccumulator. Oscillatoria and Oedogonium were highest Zn accumulating algae which showed significant difference between the means at P Cu > Pb > Cd. The present study showed that Oedogonium, Cladophora, Oscillatoria and Spirogyra were excellent bioaccumulator and could be utilized as biomonitoring agents in water bodies receiving waste contaminated by metals.

Bioaccumulation Pattern of Mercury in Bacopa monnieri (L. Pennell

Directory of Open Access Journals (Sweden)

Hussain K

2012-05-01

Full Text Available Bioaccumulation pattern of mercury was studied in Bacopa monnieri plants cultivated in Hoagland nutrient medium artificially contaminated with 5 and 10μM HgCl2. Mercury content of roots, stem and leaves were analysed using Atomic Absorption Spectrophotometry (AAS. During a period 12 days of growth, more accumulation was noticed in roots followed by stem and leaves. Repeated addition of HgCl2 and enhanced growth period up to 50 days showed only negligible increase in accumulation maintaining a threshold level of mercury in the root. When a comparison was done between the quantities of HgCl2 added to the growth medium and the sum of total accumulation of the plant and content present in the residual medium, a significant quantity of mercury is found to be lost presumably through the process of phytovolatilization from the plant. Studies on the effect of pH on bioaccumulation of mercury showed that acidic pH enhanced accumulation rate and hence for phytoremediation technology ‘chlorination’ is recommended whereas for medicinal purpose, Bacopa monnieri plants can be harvested after ‘liming’ to increase the pH and thereby reducing accumulation rate of mercury.

Structure and Dynamics of Hydroxyl-Functionalized Protic Ammonium Carboxylate Ionic Liquids.

Science.gov (United States)

Thummuru, Dhileep Nagi Reddy; Mallik, Bhabani S

2017-10-26

We performed classical molecular dynamics simulations to investigate the structure and dynamics of protic ionic liquids, 2-hydroxy ethylammonium acetate, ethylammonium hydroxyacetate, and 2-hydroxyethylammonium hydroxyacetate at ambient conditions. Structural properties such as density, radial distribution functions, spatial distribution functions, and structure factors have been calculated. Dynamic properties such as mean square displacements, as well as residence and hydrogen bond dynamics have also been calculated. Hydrogen bond lifetimes and residence times change with the addition of hydroxyl groups. We observe that when a hydroxyl group is present on the cation, dynamics become very slow and it forms a strong hydrogen bond with carboxylate oxygen atoms of the anion. The hydroxyl functionalized ILs show more dynamic diversity than structurally similar ILs.

A GIS-based tool for bioaccumulation risk analysis and its application to study polychlorinated biphenyls in the Great Lakes

Directory of Open Access Journals (Sweden)

Fernanda P. Maciel

2018-01-01

Full Text Available This paper presents a GIS-based tool named Arc-BEST (Bioaccumulation Evaluation Screening Tool to perform spatially distributed bioaccumulation risk analyses. Estimating bioaccumulation risk is important to help predict potentially adverse effects from contaminants on ecosystems and human health, which are key factors in the development of sound public policy. Arc-BEST is based on the BEST model in the U.S. Army Corps of Engineers BRAMS (Bioaccumulation Risk Assessment Modeling System software, released in 2012. It predicts concentration of concern contaminants in predators’ tissues from concentrations in organisms at the bottom of the food chain, and corresponding bioaccumulation factors. Additionally, it estimates carcinogenic and non-carcinogenic risks for humans that consume those species. The greatest contribution of Arc-BEST is that it enables the automated use of digital spatial data sets, which improves model creation speed, analysis and visualization of results, and comparison and cross-referencing with other geographic datasets. Furthermore, the model was improved to consider up to four trophic levels. The code is written in Python and is open-source. In this work Arc-BEST is used as part of a screening-level risk assessment process in order to identify hot spots where further studies and monitoring should be performed to ensure humans and ecosystems health. The tool is successfully applied to a case study in the Laurentian Great Lakes, where long-term effects of polychlorinated biphenyls (PCBs is performed, based on measured concentrations in zebra mussels (Dreissena polymorpha, and local bioaccumulation factors from previous studies. Zebra mussels have a great filtration capacity and high bioconcentration rates, increasing the bioavailability of contaminants for predator species. PCBs concentrations in different-level predators are predicted. Furthermore, health risks for humans that consume sport fish are estimated for various

Atmospheric hydroxyl radical production from electronically excited NO2 and H2O.

Science.gov (United States)

Li, Shuping; Matthews, Jamie; Sinha, Amitabha

2008-03-21

Hydroxyl radicals are often called the "detergent" of the atmosphere because they control the atmosphere's capacity to cleanse itself of pollutants. Here, we show that the reaction of electronically excited nitrogen dioxide with water can be an important source of tropospheric hydroxyl radicals. Using measured rate data, along with available solar flux and atmospheric mixing ratios, we demonstrate that the tropospheric hydroxyl contribution from this source can be a substantial fraction (50%) of that from the traditional O(1D) + H2O reaction in the boundary-layer region for high solar zenith angles. Inclusion of this chemistry is expected to affect modeling of urban air quality, where the interactions of sunlight with emitted NOx species, volatile organic compounds, and hydroxyl radicals are central in determining the rate of ozone formation.

METHOD EVALUATION TO MEASURE PERSISTENT BIOACCUMULATIVE TOXIC POLLUTANTS IN COW MILK

Science.gov (United States)

It is important to understand the persistent and bioaccumulative toxic (PBT) levels in milk, as milk fat may be one of the highest dietary sources of PBT exposure. Analysis of milk also allows the opportunity to investigate geographic variability, as milk is produced and distrib...

Study of metal bioaccumulation by nuclear microprobe analysis of algae fossils and living algae cells

International Nuclear Information System (INIS)

Guo, P.; Wang, J.; Li, X.; Zhu, J.; Reinert, T.; Heitmann, J.; Spemann, D.; Vogt, J.; Flagmeyer, R.-H.; Butz, T.

2000-01-01

Microscopic ion-beam analysis of palaeo-algae fossils and living green algae cells have been performed to study the metal bioaccumulation processes. The algae fossils, both single cellular and multicellular, are from the late Neoproterozonic (570 million years ago) ocean and perfectly preserved within a phosphorite formation. The biosorption of the rare earth element ions Nd 3+ by the green algae species euglena gracilis was investigated with a comparison between the normal cells and immobilized ones. The new Leipzig Nanoprobe, LIPSION, was used to produce a proton beam with 2 μm size and 0.5 nA beam current for this study. PIXE and RBS techniques were used for analysis and imaging. The observation of small metal rich spores (<10 μm) surrounding both of the fossils and the living cells proved the existence of some specific receptor sites which bind metal carrier ligands at the microbic surface. The bioaccumulation efficiency of neodymium by the algae cells was 10 times higher for immobilized algae cells. It confirms the fact that the algae immobilization is an useful technique to improve its metal bioaccumulation

Hydroxyl-dependent Evolution of Oxygen Vacancies Enables the Regeneration of BiOCl photocatalyst

KAUST Repository

Wu, Sujuan; Xiong, Jiawei; Sun, Jianguo; Hood, Zachary D.; Zeng, Wen; Yang, Zhenzhong; Gu, Lin; Zhang, Xixiang; Yang, Shize

2017-01-01

irradiation in the sample with surface hydroxyl groups, while variable changes were observed in samples without surface hydroxyls. Density functional theory (DFT) calculations reveal that the binding energy of Bi-O is drastically influenced by surficial

Understanding differences in the body burden-age relationships of bioaccumulating contaminants based on population cross sections versus individuals.

Science.gov (United States)

Quinn, Cristina L; Wania, Frank

2012-04-01

Body burdens of persistent bioaccumulative contaminants estimated from the cross-sectional biomonitoring of human populations are often plotted against age. Such relationships have previously been assumed to reflect the role of age in bioaccumulation. We used a mechanistic modeling approach to reproduce concentration-versus-age relationships and investigate factors that influence them. CoZMoMAN is an environmental fate and human food chain bioaccumulation model that estimates time trends in human body burdens in response to time-variant environmental emissions. Trends of polychlorinated biphenyl (PCB) congener 153 concentrations versus age for population cross sections were estimated using simulated longitudinal data for individual women born at different times. The model was also used to probe the influence of partitioning and degradation properties, length of emissions, and model assumptions regarding lipid content and liver metabolism on concentration-age trends of bioaccumulative and persistent contaminants. Body burden-age relationships for population cross sections and individuals over time are not equivalent. The time lapse between the peak in emissions and sample collection for biomonitoring is the most influential factor controlling the shape of concentration-age trends for chemicals with human metabolic half-lives longer than 1 year. Differences in observed concentration-age trends for PCBs and polybrominated diphenyl ethers are consistent with differences in emission time trends and human metabolic half-lives. Bioaccumulation does not monotonically increase with age. Our model suggests that the main predictors of cross-sectional body burden trends with age are the amount of time elapsed after peak emissions and the human metabolic and environmental degradation rates.

SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Z; Ngwa, W [University of Massachusetts Lowell, Lowell, MA (United States); Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Strack, G; Sajo, E [University of Massachusetts Lowell, Lowell, MA (United States)

2016-06-15

Purpose: Hydroxyl radicals can be produced within tissue by radiation therapy, and they are largely responsible for DNA damage and cell killing. Coumarin-3-carboxylic acid (3-CCA) and crystal violet are reported to react with hydroxyl radicals and can be used for fluorescence and absorbance measurements, respectively. This study assesses the ability of hydroxyl measurement for both 3-CCA and crystal violet in radiolized water systems in order to provide dosimetric information in radiation chemistry and radiation biology experiments. Methods: 3-CCA and crystal violet were both dissolved in phosphate buffered saline (PBS, pH 7.4) with final concentrations 0.5 mg/mL and 0.05 mg/mL. 3-CCA and control solutions (PBS only) were loaded in black bottom 96-well plates. Crystal violet and control solutions were loaded in clear bottom 96-well plates. The prepared solutions were irradiated at 2 Gy using a small animal radiation research platform. Fluorescence reading with 360 nm excitation wavelength and 485 nm emission wavelength was done for 3-CCA, and absorbance reading at wavelength 580 nm was done for crystal violet before and after radiation. Results: 3-CCA showed clear difference in fluorescence before and after radiation, which suggested hydroxyl production during radiation. However, crystal violet absorbance at 580 nm was not changed significantly by radiation. Conclusion: The overall conclusion is that 3-CCA can be used for hydroxyl measurement in radiolized water systems, while crystal violet cannot, although crystal violet is reported widely to react with hydroxyl radicals produced in Fenton reactions. Possible reasons could relate to reaction pH.

Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α upregulation in human tumours.

Directory of Open Access Journals (Sweden)

Cameron E Snell

Full Text Available The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564, was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer.

Development of a liquid chromatography-electrospray chemical ionization tandem mass spectrometry analytical method for analysis of eleven hydroxylated polybrominated diphenyl ethers.

Science.gov (United States)

Feo, Maria Luisa; Barón, Enrique; Aga, Diana S; Eljarrat, Ethel; Barceló, Damià

2013-08-02

Recently, hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have emerged as environmentally relevant pollutants due to recent reports of their natural production and metabolism. Recent mechanistic studies in human and rats have shown that some OH-PBDEs are more potent than parent compounds (PBDEs) and may contribute substantially to neurodevelopmental disorders by direct neurotoxicity, or indirectly through altered thyroid disruption. However, analytical methodologies for determination of OH-PBDEs are currently limited. In this study a robust liquid chromatography-electrospray tandem triple quadrupole-linear ion trap mass spectrometer (LC-ESI-QqLIT-MS-MS) in negative mode method was developed for the determination of eleven OH-tri- to OH-hexa-PBDEs. Two different columns were tested and compared for chromatographic separation: a C18 BetaBasic and a Purospher STAR RP 18, working at pH 8 and 10, respectively. Mobile phase (acetonitrile:water) was optimized by changing the pH of the aqueous phase and the concentration of the organic modifier (methanol). The MS-MS parameters (declustering potential (DP), collision energy (CE) and cell exit potential (CXP)) were optimized. Selected reaction monitoring (SRM) was used in order to increase sensitivity. Two SRM transitions ([M-H](-)>[Br](-)) were selected for each OH-PBDE, one for quantification and the second one for confirmation. Under the optimized conditions, the instrumental limits of detection were between 0.17 and 0.72injectedpg. The method provided good linearity (r>0.99 for a concentration range of 0.30-100ng/mL), accuracy and precision (%Dev and %RSD≤20% for intra- and inter-assays). Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation,

Science.gov (United States)

Objectives. This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Approach/Activities. Fifty-five studies were found where both passive sampler uptake...

CATALYTIC PERFORMANCES OF Fe2O3/TS-1 CATALYST IN PHENOL HYDROXYLATION REACTION

Directory of Open Access Journals (Sweden)

Didik Prasetyoko

2010-07-01

Full Text Available Hydroxylation reaction of phenol into diphenol, such as hydroquinone and catechol, has a great role in many industrial applications. Phenol hydroxylation reaction can be carried out using Titanium Silicalite-1 (TS-1 as catalyst and H2O2 as an oxidant. TS-1 catalyst shows high activity and selectivity for phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption toward the active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to be low. Addition of metal oxide Fe2O3 enhanced hydrophilicity of TS-1 catalyst. Liquid phase catalytic phenol hydroxylation using hydrogen peroxide as oxidant was carried out over iron (III oxide-modified TS-1 catalyst (Fe2O3/TS-1, that were prepared by impregnation method using iron (III nitrate as precursor and characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption, pyridine adsorption, and hydrophilicity techniques. Catalysts 1Fe2O3/TS-1 showed maximum catalytic activity of hydroquinone product. In this research, the increase of hydroquinone formation rate is due to the higher hydrophilicity of Fe2O3/TS-1 catalysts compare to the parent catalyst, TS-1.   Keywords: Fe2O3/TS-1, hydrophilic site, phenol hydroxylation

Prolyl hydroxylation regulates protein degradation, synthesis, and splicing in human induced pluripotent stem cell-derived cardiomyocytes.

Science.gov (United States)

Stoehr, Andrea; Yang, Yanqin; Patel, Sajni; Evangelista, Alicia M; Aponte, Angel; Wang, Guanghui; Liu, Poching; Boylston, Jennifer; Kloner, Philip H; Lin, Yongshun; Gucek, Marjan; Zhu, Jun; Murphy, Elizabeth

2016-06-01

Protein hydroxylases are oxygen- and α-ketoglutarate-dependent enzymes that catalyse hydroxylation of amino acids such as proline, thus linking oxygen and metabolism to enzymatic activity. Prolyl hydroxylation is a dynamic post-translational modification that regulates protein stability and protein-protein interactions; however, the extent of this modification is largely uncharacterized. The goals of this study are to investigate the biological consequences of prolyl hydroxylation and to identify new targets that undergo prolyl hydroxylation in human cardiomyocytes. We used human induced pluripotent stem cell-derived cardiomyocytes in combination with pulse-chase amino acid labelling and proteomics to analyse the effects of prolyl hydroxylation on protein degradation and synthesis. We identified 167 proteins that exhibit differences in degradation with inhibition of prolyl hydroxylation by dimethyloxalylglycine (DMOG); 164 were stabilized. Proteins involved in RNA splicing such as serine/arginine-rich splicing factor 2 (SRSF2) and splicing factor and proline- and glutamine-rich (SFPQ) were stabilized with DMOG. DMOG also decreased protein translation of cytoskeletal and sarcomeric proteins such as α-cardiac actin. We searched the mass spectrometry data for proline hydroxylation and identified 134 high confidence peptides mapping to 78 unique proteins. We identified SRSF2, SFPQ, α-cardiac actin, and cardiac titin as prolyl hydroxylated. We identified 29 prolyl hydroxylated proteins that showed a significant difference in either protein degradation or synthesis. Additionally, we performed next-generation RNA sequencing and showed that the observed decrease in protein synthesis was not due to changes in mRNA levels. Because RNA splicing factors were prolyl hydroxylated, we investigated splicing ± inhibition of prolyl hydroxylation and detected 369 alternative splicing events, with a preponderance of exon skipping. This study provides the first extensive

Hydroxyl radical induced degradation of salicylates in aerated aqueous solution

International Nuclear Information System (INIS)

Szabó, László; Tóth, Tünde; Homlok, Renáta; Rácz, Gergely; Takács, Erzsébet; Wojnárovits, László

2014-01-01

Ionizing radiation induced degradation of acetylsalicylic acid, its hydrolysis product salicylic acid and a salicylic acid derivative 5-sulpho-salicylic acid, was investigated in dilute aqueous solutions by UV–vis spectrophotometry, HPLC separation and diode-array or MS/MS detection, chemical oxygen demand, total organic carbon content and by Vibrio fischeri toxicity measurements. Hydroxyl radicals were shown to degrade these molecules readily, and first degradation products were hydroxylated derivatives in all cases. Due to the by-products, among them hydrogen peroxide, the toxicity first increased and then decreased with the absorbed dose. With prolonged irradiation complete mineralization was achieved. - Highlights: • In OH induced reactions of salicylates first products are hydroxylated derivatives. • With prolonged irradiation dihydroxy derivatives also form. • In aerated solutions the one-electron oxidant OH induces 3–4 oxidations. • Toxicity first increases and then decreases with dose mainly due to H 2 O 2 formation. • The toxicity in tap water is smaller than in pure water

Emerging and Legacy Contaminants in The Foodweb in The Lower Columbia River: USGS ConHab Project

Science.gov (United States)

Nilsen, E. B.; Alvarez, D.; Counihan, T.; Elias, E.; Gelfenbaum, G. R.; Hardiman, J.; Jenkins, J.; Mesa, M.; Morace, J.; Patino, R.; Torres, L.; Waite, I.; Zaugg, S.

2012-12-01

An interdisciplinary study, USGS Columbia River Contaminants and Habitat Characterization (ConHab) project, investigates transport pathways, chemical fate, and effects of polybrominated diphenyl ethers (PBDEs) and other endocrine disrupting chemicals (EDCs) in aquatic media and the foodweb in the lower Columbia River, Oregon and Washington. Polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs) were co-deployed at each of 10 sites in 2008 to provide a measure of the dissolved concentrations of select PBDEs, chlorinated pesticides, and other EDCs. PBDE-47 was the most prevalent of the PBDEs detected. Numerous organochlorine pesticides, both banned and current-use, including hexachlorobenzene, pentachloroanisole, dichlorodiphenyltrichloroethane (DDT) and its degradates, chlorpyrifos, endosulfan, and the endosulfan degradation products, were measured at each site. EDCs commonly detected included a series of polycyclic aromatic hydrocarbons (PAHs), fragrances (galaxolide), pesticides (chlorpyrifos and atrazine), plasticizers (phthalates), and flame retardants (phosphates). The downstream sites tended to have the highest concentrations of contaminants in the lower Columbia River. In 2009 and 2010 passive samplers were deployed and resident largescale suckers (Catostomus macrocheilus) and surface bed sediments were collected at three of the original sites representing a gradient of exposure based on 2008 results. Brain, fillet, liver, stomach, and gonad tissues were analyzed. Chemical concentrations were highest in livers, followed by brain, stomach, gonad, and, lastly, fillet. Concentrations of halogenated compounds in tissue samples ranged from PBDE-100 > PBDE-154 > PBDE-153. Concentrations in tissues and in sediments increased moving downstream from Skamania, WA to Columbia City, OR to Longview, WA. Preliminary biomarker results indicate that fish at the downstream sites experience greater stress relative to the upstream site

Rate constant for reaction of hydroxyl radicals with bicarbonate ions

International Nuclear Information System (INIS)

Buxton, G.V.; Elliot, A.J.

1986-01-01

The rate constant for reaction of hydroxyl radicals with the bicarbonate ion has been determined to be 8.5 x 10 6 dm 3 mol -1 s -1 . This value was calculated from: the measured rate of formation of the CO 3 - radical in pulsed electron irradiation of bicarbonate solutions over the pH range 7.0 to 9.4; the pK for the equilibrium HCO 3 - = CO 3 2- + H + ; and the rate constant for hydroxyl radicals reacting with the carbonate ion. (author)

11 µ-Hydroxylation of cortexolone using immobilized ...

African Journals Online (AJOL)

Transformation of cortexolone to cortisol and prednisolone by the filamentous fungus Cunninghamella elegans protoplasts as a research tool was studied. The immobilized protoplasts of the fungus hydroxylated cortexolone at 11β -position had significantly higher activity than the free protoplasts. Sucrose as an osmotic ...

NATIONAL COW MILK SURVEY FOR PERSISTENT, BIOACCUMULATIVE AND TOXIC (PBT) POLLUTANTS

Science.gov (United States)

This is a survey for persistent, bioaccumulative, and toxic (PBT) pollutants in the U.S. milk supply. The EPA Environmental Radiation Ambient Monitoring System (ERAMS) was used to collect two sets of milk samples, one set in July 2000 and the second in January 2001. ERAMS has abo...

Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680.

Science.gov (United States)

Roh, Changhyun; Seo, Su-Hyun; Choi, Kwon-Young; Cha, Minho; Pandey, Bishnu Prasad; Kim, June-Hyung; Park, Jun-Seong; Kim, Duck Hee; Chang, Ih Seop; Kim, Byung-Gee

2009-07-01

Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.

Monkey liver cytochrome P450 2C19 is involved in R- and S-warfarin 7-hydroxylation.

Science.gov (United States)

Hosoi, Yoshio; Uno, Yasuhiro; Murayama, Norie; Fujino, Hideki; Shukuya, Mitsunori; Iwasaki, Kazuhide; Shimizu, Makiko; Utoh, Masahiro; Yamazaki, Hiroshi

2012-12-15

Cynomolgus monkeys are widely used as primate models in preclinical studies. However, some differences are occasionally seen between monkeys and humans in the activities of cytochrome P450 enzymes. R- and S-warfarin are model substrates for stereoselective oxidation in humans. In this current research, the activities of monkey liver microsomes and 14 recombinantly expressed monkey cytochrome P450 enzymes were analyzed with respect to R- and S-warfarin 6- and 7-hydroxylation. Monkey liver microsomes efficiently mediated both R- and S-warfarin 7-hydroxylation, in contrast to human liver microsomes, which preferentially catalyzed S-warfarin 7-hydroxylation. R-Warfarin 7-hydroxylation activities in monkey liver microsomes were not inhibited by α-naphthoflavone or ketoconazole, and were roughly correlated with P450 2C19 levels and flurbiprofen 4-hydroxylation activities in microsomes from 20 monkey livers. In contrast, S-warfarin 7-hydroxylation activities were not correlated with the four marker drug oxidation activities used. Among the 14 recombinantly expressed monkey P450 enzymes tested, P450 2C19 had the highest activities for R- and S-warfarin 7-hydroxylations. Monkey P450 3A4 and 3A5 slowly mediated R- and S-warfarin 6-hydroxylations. Kinetic analysis revealed that monkey P450 2C19 had high V(max) and low K(m) values for R-warfarin 7-hydroxylation, comparable to those for monkey liver microsomes. Monkey P450 2C19 also mediated S-warfarin 7-hydroxylation with V(max) and V(max)/K(m) values comparable to those for recombinant human P450 2C9. R-warfarin could dock favorably into monkey P450 2C19 modeled. These results collectively suggest high activities for monkey liver P450 2C19 toward R- and S-warfarin 6- and 7-hydroxylation in contrast to the saturation kinetics of human P450 2C9-mediated S-warfarin 7-hydroxylation. Copyright © 2012 Elsevier Inc. All rights reserved.

Modelling 2,4-dichlorophenol bioavailability and bioaccumulation by the freshwater fingernail clam Sphaerium corneum using artificial particles and humic acids

International Nuclear Information System (INIS)

Verrengia Guerrero, N.R.; Taylor, M.G.; Simkiss, K.

2007-01-01

The complex and variable composition of natural sediments makes it very difficult to predict the bioavailability and bioaccumulation of sediment-bound contaminants. Several approaches have been proposed to overcome this problem, including an experimental model using artificial particles with or without humic acids as a source of organic matter. For this work, we have applied this experimental model, and also a sample of a natural sediment, to investigate the uptake and bioaccumulation of 2,4-dichlorophenol (2,4-DCP) by Sphaerium corneum. Additionally, the particle-water partition coefficients (K d ) were calculated. The results showed that the bioaccumulation of 2,4-DCP by clams did not depend solely on the levels of chemical dissolved, but also on the amount sorbed onto the particles and the characteristics and the strength of that binding. This study confirms the value of using artificial particles as a suitable experimental model for assessing the fate of sediment-bound contaminants. - An experimental model is proposed to better understand the bioavailability and bioaccumulation of sediment-bound 2,4-dichlorophenol

Synthesis of hydroxyl liquid polybutadiene by photochemical decomposition of hydrogen peroxide

International Nuclear Information System (INIS)

Moutinho, Marcus Tadeu Moura

1995-01-01

The synthesis of hydroxyl terminated polybutadienes (HTPB) by photochemical decomposition (λ=254 nm) of hydrogen peroxide (H 2 O 2 ) in alcoholic medium was studied. The influence of reaction time, H 2 O 2 and alcohol concentrations, type of alcohol and radiation intensity on the polymerization rate was determined. Higher polymerization rates were attained when t-butyl alcohol was used as the compatibilizing agent (19% conversion after 8 hours). The HTPBs were characterized by hydroxyl content (acetylation), functionality, IR microstructure and types of hydroxyl groups ( 1 H-NMR and 13 C-NMR), 2-vinyl cyclohexene (VCH) content and viscosity. The polymers showed molecular weights (Mn) in the range of 458 to 1,099, molecular weight distribution (Mw/Mn) in the range of 1.20 to 1.46 and functionality between 1.2 and 3.2 depending on the alcohol used. NMR results 1 H and 13 C) revealed low cis content for the polybutadienes and identified primary and secondary hydroxyl groups, depending on the alcohol employed as compatibilizing agent. The incorporation of alcohol in polymer chain ends was evidenced. The produced HTPBs presented viscosities in the range of 850 to 1,250 cP (at 25 deg C) and were VCH free. (author)

Distribution, bioaccumulation and trophic transfer of chlorinated polyfluoroalkyl ether sulfonic acids in the marine food web of Bohai, China.

Science.gov (United States)

Chen, Hong; Han, Jianbo; Cheng, Jiayi; Sun, Ruijun; Wang, Xiaomeng; Han, Gengchen; Yang, Wenchao; He, Xin

2018-06-04

Chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs) caused great concerns recently as novel fluorinated alternatives. However, information on their bioconcentration, bioaccumulation and biomagnification in marine ecosystems is limited. In this study, 152 biological samples including invertebrates, fishes, seabirds and mammals collected from Bohai Sea of China were analyzed to investigate the residual level, spatial distribution, bioaccumulation and biomagnification of Cl-PFESAs. 6:2 Cl-PFESA was found in concentrations ranging from bioaccumulation factors (BAFs) for 6:2 Cl-PFESA ranged from 2.23 to 4.21, implying the bioaccumulation of this compound. The trophic magnification factor (BMF) for 6:2 Cl-PFESA was determined to be 3.37 in the marine food web, indicating biomagnification potential along the marine food chain. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of soil stabilization by chemical extraction and bioaccumulation using earthworm, Eisenia fetida

Science.gov (United States)

Lee, Byung-Tae; Abd Aziz, Azilah; Han, Heop Jo; Kim, Kyoung-Woong

2014-05-01

Soil stabilization does not remove heavy metals from contaminated soil, but lowers their exposures to ecosystem. Thus, it should be evaluated by measuring the fractions of heavy metals which are mobile and/or bioavailable in soils. The study compared several chemical extractions which intended to quantify the mobile or bioaccessible fractions with uptake and bioaccumulation by earthworm, Eisenia fetida. Soil samples were taken from the abandoned mine area contaminated with As, Cd, Cu, Pb and/or Zn. To stabilize heavy metals, the soils were amended with limestone and steel slag at 5% and 2% (w/w), respectively. All chemical extractions and earthworm tests were applied to both the contaminated and the stabilized soils with triplicates. The chemical extractions consisted of six single extractions which were 0.01M CaCl2 (unbufferred), EDTA or DTPA (chelating), TCLP (acidic), Mehlich 3 (mixture), and aqua regia (peudo-total). Sequential extractions were also applied to fractionate heavy metals in soils. In earthworm tests, worms were exposed to the soils for uptake of heavy metals. After 28 days of exposure to soils, worms were transferred to clean soils for elimination. During the tests, three worms were randomly collected at proper sampling events. Worms were rinsed with DI water and placed on moist filter paper for 48 h for depuration. Filter paper was renewed at 24 h to prevent coprophagy. The worms were killed with liquid nitrogen, dried in the oven, and digested with aqua regia for ICP-MS analysis. In addition to the bioaccumulation, several toxicity endpoints were observed such as burrowing time, mortality, cocoon production, and body weight changes. Toxicokinetics was applied to determine the uptake and elimination heavy metals by the earthworms. Bioaccumulation factor (BAF) was estimated using total metal concentrations and body burdens. Pearson correlation and simple linear regression were applied to evaluate the relationship between metal fractions by single

Mechanism of aromatic hydroxylation of lidocaine at a Pt electrode under acidic conditions

NARCIS (Netherlands)

Gul, Turan; Bischoff, Rainer; Permentier, Hjalmar P.

2017-01-01

Aromatic hydroxylation reactions, which are mainly catalyzed by cytochrome P450 (CYP) enzymes in vivo, are some of the most important reactions of Phase I metabolism, because insertion of a hydroxyl group into a lipophilic drug compound increases its hydrophilicity and prepares it for subsequent

Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

International Nuclear Information System (INIS)

Sekiguchi, H; Ando, M; Kojima, H

2005-01-01

The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C 4 -compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C 4 -compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring

Bioaccumulation of microcystins in invasive bivalves: A case study from the boreal lagoon ecosystem

Directory of Open Access Journals (Sweden)

Aistė Paldavičienė

2015-01-01

Full Text Available In the current study we present the first report on the bioaccumulation of microcystins (MC in zebra mussel Dreissena polymorpha from the eutrophic brackish water Curonian Lagoon. The bioaccumulation capacity was related to age structure of mussels and ambient environmental conditions. We also discuss the relevant implications of these findings for biomonitoring of toxic cyanobacteria blooms in the Curonian Lagoon and potential consequences for D. polymorpha cultivation activities considered for the futures as remediation measure. Samples for the analysis were collected twice per year, in June and September, in 2006, 2007 and 2008, from two sites within the littoral zone of the lagoon. The highest microcystin concentrations were measured in mussels larger than 30 mm length and sampled in 2006 (when a severe toxic cyanobacteria bloom occurred. In the following years, a consistent reduction in bioaccumulated MC concentration was noticed. However, certain amount of microcystin was recorded in mussel tissues in 2007 and 2008, when no cyanotoxins were reported in the phytoplankton. Considering high depuration rates and presence of cyanotoxins in the bottom sediments well after the recorded toxic blooms, we assume mechanism of secondary contamination when microcystin residuals could be uptaken by mussels with resuspended sediment particles.

Bioaccumulation of organic micropollutants in different aquatic organisms. Sublethal toxic effects on fish

NARCIS (Netherlands)

van der Oost, Ron; Heida, Henk; Opperhuizen, Antoon; Vermeulen, Nico P E

1991-01-01

Bioaccumulation of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) was investigated in plankton, crustaceans, and fish from two relatively small Amsterdam lakes, with different levels of contamination. Ratios between contaminant

Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural Soil

OpenAIRE

Rønhede, Stig; Jensen, Bo; Rosendahl, Søren; Kragelund, Birthe B.; Juhler, René K.; Aamand, Jens

2005-01-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N′,N′-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N′,N′-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N′,N′-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N-(4-isopropylphenyl)-N′-methylurea. In soils, however, hydroxylated metaboli...

Influences on Mercury Bioaccumulation Factors for the Savannah River

International Nuclear Information System (INIS)

Paller, M.H.

2003-01-01

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118 km reach of the Savannah River demonstrated that species specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat and season related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 106 for largemouth bass, 1.4 x 106 for sunfishes, and 2.5 x 106 for white catfish. Inaccurate and imprecise BAFs can result in unnecessary economic impact or insufficient protection of human health. Determination of representative and precise BAFs for mercury in fish FR-om large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle FR-om the entire area and all habitats to be represented by the TMDL

Hydroxyl-radical induced dechlorination of pentachlorophenol in water

International Nuclear Information System (INIS)

He Yongke; Wu Jilan; Fang Xingwang; Sonntag, C. von

1998-01-01

The hydroxyl-radical induced dechlorination of pentachlorophenol (PCP) in water has been investigated pulse radiolytically. Hydroxyl radicals react with PCP by both electron transfer and addition. The former process results in pentachlorophenoxyl radicals (PCP-O), the latter process followed by rapid HCl elimination gives birth to deprotonated hydroxytetrachlorophenoxyl radicals ( - O-TCP-O). These phenoxyl radicals exhibit maximum absorption around 452 nm, which hinders the proper estimation of the ratio of the two processes. However, these two processes cause different changes in conductivity. In basic solution, the electron transfer causes a conductivity increase due to the formation of OH - whereas an addition followed by HCl elimination results in a conductivity decrease. The concurrence of these two processes reduces the relative variation in conductivity, from which about 53% electron transfer is deduced

Modeling the effect of water chemistry on the bioaccumulation of waterborne cadmium in zebra mussels.

Science.gov (United States)

Bourgeault, Adeline; Gourlay-Francé, Catherine; Tusseau-Vuillemin, Marie-Hélène

2010-10-01

The present study aims at investigating the effects of Zn, Ca, and dissolved organic carbon (DOC) on the waterborne Cd bioaccumulation of a freshwater bivalve (Dreissena polymorpha). Mussels were exposed for 48 h at 3 µg/L of Cd in different media. Their physiological activities were assessed by separately measuring the filtration rate in the same exposure water. Increased Zn (from 3 to 89 µg/L) and Ca (from 37 to 131 mg/L) concentrations in water led to a threefold and sevenfold reduction of Cd bioaccumulation, whereas the effect of DOC varied greatly depending on its concentration. At low DOC concentrations (from 0.2 to 1.1 mg/L), the uptake of Cd increased, whereas at higher concentrations (from 1.1 to 17.1 mg/L), the uptake decreased. The filtration activity was not strongly influenced by either Zn or Ca concentration, whereas it was modified in enriched DOC media in the same manner as Cd uptake. A competitive model was built to predict the waterborne uptake rate constant of Cd (k (u)) as a function of Zn and Ca concentrations in the water. Over the range of DOC concentrations we tested, organic matter was shown to influence Cd bioaccumulation in two ways: by modifying Cd speciation and thus its bioavailability and its interaction with the biological membrane, and by affecting the mussel's physiology and therefore its sensitivity to metal. The present study provides a useful means of adjusting the toxicokinetic constant to the water's physicochemical characteristics and proposes a unifying model that takes into account the different geochemical and biological influences on bioaccumulation. Environ. Toxicol. Chem. 2010;29:2182-2189. © 2010 SETAC.

BIOACCUMULATION AND BIOTRANSFORMATION OF CHIRAL TRIAZOLE FUNGICIDES IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Science.gov (United States)

There are very little data on the bioaccumulation and biotransformation of current-use pesticides (CUPs) despite the fact that such data are critical in assessing their fate and potential toxic effects in aquatic organisms. To help address this issue, juvenile rainbow trout (Onco...

Precipitation and temperature drive seasonal variation in bioaccumulation of polycyclic aromatic hydrocarbons in the planktonic food webs of a subtropical shallow eutrophic lake in China.

Science.gov (United States)

Tao, Yuqiang; Yu, Jing; Xue, Bin; Yao, Shuchun; Wang, Sumin

2017-04-01

Hydrophobic organic contaminants (HOCs) are toxic and ubiquitous in aquatic environments and pose great risks to aquatic organisms. Bioaccumulation by plankton is the first step for HOCs to enter aquatic food webs. Trophic status is considered to dominate variations in bioaccumulation of HOCs in plankton in temperate and frigid deep oligotrophic waters. However, long-term driving factors for bioaccumulation of HOCs in planktonic food webs of subtropical shallow eutrophic waters have not been well investigated. China has the largest subtropical lake density in the Northern Hemisphere. Due to limited field data, long-term variations in the bioaccumulation of HOCs in these lakes are almost unknown. Here we take Lake Xuanwu as an example to investigate long-term variations in the bioaccumulation, and biomagnification of polycyclic aromatic hydrocarbon (PAHs) in planktonic food webs of subtropical shallow eutrophic lakes in China, and elucidate the driving factors. Our results indicate that temperature rather than nutrients dominates long-term dynamics of planktonic biomass in this lake. Precipitation significantly enhances the concentrations of the PAHs, and total suspended particles, and consequently affects the distribution of the PAHs in the water column. Biomass dilution induced by temperature dominates bioaccumulation of the PAHs by both phytoplankton and zooplankton (copepods and cladocerans). Biomagnification of the PAHs from phytoplankton to zooplankton is positively correlated with temperature. Our study suggests that temperature and precipitation drive long-term variations in the bioaccumulation of the PAHs in the planktonic food webs of this subtropical shallow eutrophic lake. Lake Xuanwu has a similar mean annual temperature, annual precipitation, sunshine duration, and nutrient levels as other subtropical shallow eutrophic lakes in China. This study may also help to understand the bioaccumulation of HOCs in planktonic food webs of other subtropical shallow

Distribution of total and methylmercury in different ecosystem compartments in the Everglades: Implications for mercury bioaccumulation

International Nuclear Information System (INIS)

Liu Guangliang; Cai Yong; Philippi, Thomas; Kalla, Peter; Scheidt, Daniel; Richards, Jennifer; Scinto, Leonard; Appleby, Charlie

2008-01-01

We analyzed Hg species distribution patterns among ecosystem compartments in the Everglades at the landscape level in order to explore the implications of Hg distribution for Hg bioaccumulation and to investigate major biogeochemical processes that are pertinent to the observed Hg distribution patterns. At an Everglade-wide scale, THg concentrations were significantly increased in the following order: periphyton < flocculent material (floc) < soil, while relatively high MeHg concentrations were observed in floc and periphyton. Differences in the methylation potential, THg concentration, and MeHg retention capacity could explain the relatively high MeHg concentrations in floc and periphyton. The MeHg/THg ratio was higher for water than for soil, floc, or periphyton probably due to high dissolved organic carbon (DOC) concentrations present in the Everglades. Mosquitofish THg positively correlated with periphyton MeHg and DOC-normalized water MeHg. The relative THg and MeHg distribution patterns among ecosystem compartments favor Hg bioaccumulation in the Everglades. - Mercury bioaccumulation in Florida Everglades is related to the distribution patterns of mercury species among ecosystem compartments

Distribution of total and methylmercury in different ecosystem compartments in the Everglades: Implications for mercury bioaccumulation

Energy Technology Data Exchange (ETDEWEB)

Liu Guangliang [Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States); Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Cai Yong [Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States); Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States)], E-mail: cai@fiu.edu; Philippi, Thomas [Department of Biological Sciences, Florida International University, Miami, FL 33199 (United States); Kalla, Peter; Scheidt, Daniel [US Environmental Protection Agency, Region 4, Science and Ecosystem Support Division, Athens, GA 30605 (United States); Richards, Jennifer [Department of Biological Sciences, Florida International University, Miami, FL 33199 (United States); Scinto, Leonard [Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Appleby, Charlie [US Environmental Protection Agency, Region 4, Science and Ecosystem Support Division, Athens, GA 30605 (United States)

2008-05-15

We analyzed Hg species distribution patterns among ecosystem compartments in the Everglades at the landscape level in order to explore the implications of Hg distribution for Hg bioaccumulation and to investigate major biogeochemical processes that are pertinent to the observed Hg distribution patterns. At an Everglade-wide scale, THg concentrations were significantly increased in the following order: periphyton < flocculent material (floc) < soil, while relatively high MeHg concentrations were observed in floc and periphyton. Differences in the methylation potential, THg concentration, and MeHg retention capacity could explain the relatively high MeHg concentrations in floc and periphyton. The MeHg/THg ratio was higher for water than for soil, floc, or periphyton probably due to high dissolved organic carbon (DOC) concentrations present in the Everglades. Mosquitofish THg positively correlated with periphyton MeHg and DOC-normalized water MeHg. The relative THg and MeHg distribution patterns among ecosystem compartments favor Hg bioaccumulation in the Everglades. - Mercury bioaccumulation in Florida Everglades is related to the distribution patterns of mercury species among ecosystem compartments.

Bioaccumulation of 137Cs and 57Co by five marine phytoplankton species

International Nuclear Information System (INIS)

Heldal, H.E.; Stupakoff, I.; Fisher, N.S.

2001-01-01

Under controlled laboratory conditions, we have examined the bioaccumulation of 137 Cs and 57 Co in three prymnesiophytes, the coccolithophorid Emiliania huxleyi and the non-calcareous species Isochrysis galbana and Phaeocystis globosa, and two diatoms Skeletonema costatum and Thalassiosira pseudonana. We measured the uptake in growing and non-growing cells and determined concentration factors on both volume and dry weight bases. For uptake of 57 Co in non-growing cells, volume concentration factors (VCF) at equilibrium ranged from 0.2x10 3 for E. huxleyi to 4x10 3 for T. pseudonana. For uptake of 137 Cs in non-growing cells, the VCFs were low for all species and the uptake pattern seemed unsystematic. The results suggest that, in contrast to Co, the cycling and bioaccumulation of Cs in marine animals are unlikely to be affected by Cs accumulation in primary producers

Bioaccumulation of trace elements in pelagic fish from the Western Indian Ocean

International Nuclear Information System (INIS)

Kojadinovic, Jessica; Potier, Michel; Le Corre, Matthieu; Cosson, Richard P.; Bustamante, Paco

2007-01-01

Trace elements were analyzed in fish of commercial interest to determine their importance in marine systems of the Western Indian Ocean and their bioaccumulation patterns. The results are equivalent or lower than levels reported in ichthyofauna worldwide. Certain values of muscular Cd, Hg, Pb and Zn were, however, above thresholds for human consumption. Levels varied among tissues, species and fish length, but were seldom influenced by the nutritional condition of the fish, its gender and its reproductive status. Correlations between hepatic Hg and Se levels in Swordfish (r 2 = 0.747) and Yellowfin Tunas (r 2 = 0.226), and among metallothionein linking metals imply the existence of detoxification processes in these species. Level differences between fish from the Mozambique Channel and Reunion Island reflect differences of diets rather than differences of elemental availability in both environments. - Metal bioaccumulation was quantified in four species of pelagic fish

Sewage sludge biochar influence upon rice (Oryza sativa L) yield, metal bioaccumulation and greenhouse gas emissions from acidic paddy soil.

Science.gov (United States)

Khan, Sardar; Chao, Cai; Waqas, Muhammad; Arp, Hans Peter H; Zhu, Yong-Guan

2013-08-06

Biochar addition to soil has been proposed to improve plant growth by increasing soil fertility, minimizing bioaccumulation of toxic metal(liod)s and mitigating climate change. Sewage sludge (SS) is an attractive, though potentially problematic, feedstock of biochar. It is attractive because of its large abundance; however, it contains elevated concentrations of metal(loid)s and other contaminants. The pyrolysis of SS to biochar (SSBC) may be a way to reduce the availability of these contaminants to the soil and plants. Using rice plant pot experiments, we investigated the influence of SSBC upon biomass yield, bioaccumulation of nutrients, and metal(loid)s, and green housegas (GHG) emissions. SSBC amendments increased soil pH, total nitrogen, soil organic carbon and available nutrients and decreased bioavailable As, Cr, Co, Ni, and Pb (but not Cd, Cu, and Zn). Regarding rice plant properties, SSBC amendments significantly (P ≤ 0.01) increased shoot biomass (71.3-92.2%), grain yield (148.8-175.1%), and the bioaccumulation of phosphorus and sodium, though decreased the bioaccumulation of nitrogen (except in grain) and potassium. Amendments of SSBC significantly (P ≤ 0.05) reduced the bioaccumulation of As, Cr, Co, Cu, Ni, and Pb, but increased that of Cd and Zn, though not above limits set by Chinese regulations. Finally regarding GHG emissions, SSBC significantly (P rice paddy soil but the actual associated benefits will depend on site-specific conditions and source of SS; long-term effects remain a further unknown.

Bioaccumulation factor of tritium in oyster and tilapia

International Nuclear Information System (INIS)

Garcia, T.Y.; Juan, N.B.

1984-01-01

This paper reports on the bioaccumulation factor as well as the residence time of tritium in marine organisms such as tilapia fish (Tilapia mossambica) and oyster (Crassostrea iredalei) reared under laboratory conditions. The organisms were submerged in aquarium water containing tritium with specific activity of 1.0 nCi/ml. The samples were analyzed for tissue-free water tritium (TFWT) by freeze drying and for tissue-bound tritium (TBT) by combustion methods. Tritiated water collected was assayed using the liquid scintillation counting technique. (author)

Contribution to freshwater hydro systems multi pollution study: experimental study of metallic and organic micro-pollutants on radionuclides bioaccumulation by fish

International Nuclear Information System (INIS)

Ausseil, O.

2001-07-01

The influence of some metallic (cadmium, zinc) and organic (17 β-oestradiol, atrazine, polychlorinated biphenyls, polycyclic aromatic hydrocarbons) pollutants on artificial radionuclide ( 110m Ag, 134 Cs 57 Co) bioaccumulation characteristics by rainbow trout (Oncorhynchus mykiss) has been tested. The basic hypothesis of this work assume that the organisms' exposure to pollutants induces mechanisms of response which could modify radionuclides bioaccumulation characteristics. During the experiments, some biological and biochemical (bio-markers) analyses were performed in order to characterize the nature and the intensity of induced stress in the organisms. These experiments were performed in field and in laboratory. The results show that a cadmium and zinc exposure leads to the induction of systems against oxidative stress or systems implied in metal sequestration. It also leads to a strong reduction of 110m Ag (- 60 %) and 134 Cs (- 33 %) bioaccumulation. No effect has been observed on 57 Co bioaccumulation. For all tested organic compounds except for fluoranthene, exposure leads to an increase of radioactive caesium ( + 10 to 45 %) and cobalt (+ 30 to 60 %) quantities bio-accumulated by rainbow trout. Only 17 β-oestradiol exposure leads to an increase of 110m Ag uptake by rainbow trout. Some hypothesis concerning the involved mechanisms are proposed, and the main implications of this work in operational radioecology are discussed. (author)

Modeling bioaccumulation in humans using poly-parameter linear free energy relationships (PPLFERS)

Energy Technology Data Exchange (ETDEWEB)

Undeman, Emma, E-mail: emma.undeman@itm.su.se; Czub, Gertje; McLachlan, Michael S.

2011-04-01

Chemical partition coefficients between environmental media and biological tissues are a key component of bioaccumulation models. The single-parameter linear free energy relationships (spLFERs) commonly used for predicting partitioning are often derived using apolar chemicals and may not accurately capture polar chemicals. In this study, a poly-parameter LFER (ppLFER) based model of organic chemical bioaccumulation in humans is presented. Chemical partitioning was described by an air-body partition coefficient that was a volume weighted average of ppLFER based partition coefficients for the major organs and tissues constituting the human body. This model was compared to a spLFER model treating the body as a mixture of lipid ({approx} octanol) and water. Although model agreement was good for hydrophobic chemicals (average difference 15% for log K{sub OW} > 4 and log K{sub OA} > 8), the ppLFER model predicted {approx} 90% lower body burdens for hydrophilic chemicals (log K{sub OW} < 0). This was mainly due to lower predictions of muscle and adipose tissue sorption capacity for these chemicals. A comparison of the predicted muscle and adipose tissue sorption capacities of hydrophilic chemicals with measurements indicated that the ppLFER and spLFER models' uncertainties were similar. Consequently, little benefit from the implementation of ppLFERs in this model was identified. - Research Highlights: {yields}Implementation of ppLFERs resulted in on average 90% lower predicted body burdens. {yields}Uncertainties in spLFER and ppLFER predictions were similar. {yields}The benefit from implementation of ppLFERs in bioaccumulation models was limited.

Environmental contaminants in arctic foxes (Alopex lagopus) in Svalbard: Relationships with feeding ecology and body condition

International Nuclear Information System (INIS)

Fuglei, E.; Bustnes, J.O.; Hop, H.; Mork, T.; Bjoernfoth, H.; Bavel, B. van

2007-01-01

Adipose tissues from 20 arctic foxes (Alopex lagopus) of both sexes from Svalbard were analysed for polybrominated diphenyl ether (PBDE), polychlorinated biphenyl (PCB), p,p'-dichlorodiphenyltrichloroethane (DDE), chlordane, and hexachlorobenzene (HCB) concentrations. Gender (0.43 15 N from muscle samples and showed significantly positive relationship with all contaminants, with the exception of HCB concentrations. This indicates that foxes feeding at high trophic levels had higher tissue contaminant levels as a result of bioaccumulation in the food chain. - High contaminant concentrations in the coastal ecotype of arctic fox may cause toxic health effects due to huge annual cyclic variation in storage and mobilisation of adipose tissue

Selenium bioaccumulation in fish exposed to coal ash at the Tennessee Valley Authority Kingston spill site.

Science.gov (United States)

Mathews, Teresa J; Fortner, Allison M; Jett, R Trent; Morris, Jesse; Gable, Jennifer; Peterson, Mark J; Carriker, Neil

2014-10-01

In December 2008, 4.1 million cubic meters of coal ash were released into the Emory and Clinch Rivers by the Tennessee Valley Authority Kingston Fossil Plant. Coal ash contains several contaminants, including the bioaccumulative metalloid selenium (Se). Because Se is predominantly accumulated in aquatic organisms through dietary rather than aqueous exposure, tissue-based toxicity thresholds for Se are currently being considered. The proposed threshold concentrations range between 4 μg/g and 9 μg/g Se (dry wt.) in whole body fish, with a proposed fillet threshold of 11.8 μg/g. In the present study, the authors examined the spatial and temporal trends in Se bioaccumulation and examined the relationship between the Se content in fillets and in whole bodies of fish collected around the Kingston spill site to determine whether Se bioaccumulation was a significant concern at the ash spill site. Whereas Se concentrations in fish (whole bodies and fillets) were elevated at sampling locations affected by the Kingston ash spill relative to reference locations, concentrations do not appear to be above risk thresholds and have not been increasing over the 5-yr period since the spill. These findings are not only relevant to guiding the human health and ecological risk assessments at the Kingston ash spill site, but because of current national discussions on appropriate guidelines for Se in fish as well for the disposal of coal combustion wastes, the results are also relevant to the general understanding of Se bioaccumulation in contaminated water bodies. © 2014 SETAC.

Risk Assessment of Bioaccumulation Substances. Part II: Description of a Model Framework

NARCIS (Netherlands)

Tamis, J.E.; Vries, de P.; Karman, C.C.

2009-01-01

This report provides a proposal for a framework for risk assessment of bioaccumulative substances, either from produced water discharges or present as background contamination. The proposed framework is such that it is compatible to the current EIF risk assessment models that are used in the

On the spatial coincidence of hydroxyl and methanol masers

Science.gov (United States)

Hartquist, T. W.; Menten, K. M.; Lepp, S.; Dalgarno, A.

1995-01-01

We argue that purely gas-phase chemical models for the production of OH in hydroxyl masers around ultracompact H II regions such as W3(OH) cannot account for the CH_3OH in the methanol masers that are found to coincide with the hydroxyl masers in these sources. We suggest that the CH_3OH in the masers is injected into the gas phase by evaporation of the grain mantles, the grains being heated by the passage of weak shocks. Gas evaporation also injects H_2O into the gas. Photodissociation of H_2O, CH_3OH and OH occur at similar rates, and substantial abundances of CH_3OH and OH coexist.

Mercury Speciation and Bioaccumulation In Riparian and Upland Food Webs of the White Mountains Region, New Hampshire, USA

Science.gov (United States)

Rodenhouse, N.; Gebauer, R.; Lowe, W.; McFarland, K.; Bank, M. S.

2015-12-01

The soils and foods webs associated with mid to high elevation, forested, headwater streams are potential hotspots for mercury methylation and bioaccumulation but are not well studied. We tested the hypothesis that spatial variation in mercury bioaccumulation in upland taxa associated with headwater streams can be explained by variation in soil conditions promoting Hg methylation such as soil moisture, pH, and sulfur and organic matter content. We sampled at high (c. 700m) and mid elevation (c. 500m) in northern hardwood forest adjacent to and away from (75m) replicate headwater streams in the Hubbard Brook and Jeffers Brook watersheds of the White Mountains region, New Hampshire, USA. These forested watersheds differed primarily in soil calcium content and pH. We measured and assessed spatial variation in total Hg (THg) and methyl Hg (MeHg) concentrations in soils, insects, spiders, salamanders and birds. We also tested whether trophic position, as determined by nitrogen stable isotopes, was a major predictor of Hg bioaccumulation across these riparian and upland forest taxa. We found elevated levels of THg in all measured components of the food web, and conditions for methylation were better in the upland forest sites compared to the riparian sites located adjacent to headwater streams. Both THg and MeHg in biota were positively correlated with trophic position as indicated by 15N enrichment. In fact, trophic position was a better predictor of THg and MeHg content than spatial location, but the spatial patterning of bioaccumulation differed among taxa. Our data show that that significant Hg bioaccumulation and biomagnification can occur in soils and food webs of mid to high elevation temperate deciduous forests of the Northeast. They also suggest that mercury methylation in forested watersheds is a widespread phenomenon and not limited to areas with high soil moisture, such as lotic environments.

Effects of climate change on bioaccumulation and biomagnification of polycyclic aromatic hydrocarbons in the planktonic food web of a subtropical shallow eutrophic lake in China.

Science.gov (United States)

Tao, Yuqiang; Xue, Bin; Lei, Guoliang; Liu, Fei; Wang, Zhen

2017-04-01

To date effects of climate change on bioaccumulation and biomagnification of chemical pollutants in planktonic food webs have rarely been studied. Recruitments of plankton have shifted earlier due to global warming. Global warming and precipitation patterns are projected to shift seasonally. Whether and how the shifts in plankton phenology induced by climate change will impact bioaccumulation and biomagnification of chemical pollutants, and how they will respond to climate change are largely unknown. Here, we combine data analysis of the past seven decades, high temporal resolution monitoring and model development to test this hypothesis with nine polycyclic aromatic hydrocarbons (PAHs) in the planktonic food web of a subtropical shallow eutrophic lake in China. We find biphasic correlations between both bioconcentration factors and bioaccumulation factors of the PAHs and the mean temperature, which depend on the recruitment temperatures of cyanobacteria, and copepods and cladocerans. The positive correlations between bioconcentration factors, bioaccumulation factors and the mean temperature will be observed less than approximately 13-18 days by 2050-2060 due to the shifts in plankton phenology. The PAHs and their bioaccumulation and biomagnification will respond seasonally and differently to climate change. Bioaccumulation of most of the PAHs will decrease with global warming, with higher decreasing rates appearing in winter and spring. Biomagnification of most of the PAHs from phytoplankton to zooplankton will increase with global warming, with higher increasing rates appearing in winter and spring. Our study provides novel insights into bioaccumulation and biomagnification of chemical pollutants in eutrophic waters under climate change scenarios. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of humic substances on the aqueous solubility, uptake and bioaccumulation of platinum, palladium and rhodium in exposure studies with Dreissena polymorpha

International Nuclear Information System (INIS)

Sures, Bernd; Zimmermann, Sonja

2007-01-01

Zebra mussels (Dreissena polymorpha) were exposed to different types of water containing PGE salts (PtCl 4 , PdSO 4 , RhCl 3 ) to investigate the influence of humic substances on the aqueous solubility, uptake and bioaccumulation of noble metals. The results showed a time dependent decrease of the aqueous PGE concentrations in tank water for all groups. This could mainly be related to non-biological processes. The aqueous solubility of Pd and Rh was higher in humic water compared with non-chlorinated tap water, whereas Pt showed opposing results. Highest metal uptake rates and highest bioaccumulation plateaus were found for Pd, followed by Pt and Rh. Pd uptake and bioaccumulation was significantly hampered by humic substances, whose presence appear to increase Pt uptake and bioaccumulation. No clear trend emerged for Rh. Differences in effects of humic matter among the PGE may be explained by formation of metal complexes with different fractions of humic substances. - Precious metal accumulation in Dreissena polymorpha is affected by humic substances

EPR detection of hydroxyl radical generation and its interaction with antioxidant system in Carassius auratus exposed to pentachlorophenol

Energy Technology Data Exchange (ETDEWEB)

Luo Yi [Key Laboratory of Pollution Processes and Environmental Criteria (Nankai University), Ministry of Education, College of Environmental Sciences and Engineering, Nankai University, Tianjin 300071 (China); Wang Xiaorong, E-mail: yiyluo@gmail.com [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093 (China); Ji Liangliang; Su Yan [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093 (China)

2009-11-15

In the present study, direct evidence of hydroxyl radical production in livers of Carassius auratus exposed to pentachlorophenol (PCP) was provided using electron paramagnetic resonance (EPR) with spin-trapping. A dose-effect relationship was obtained between hydroxyl radical intensities and PCP exposure. It was observed that hydroxyl radical was significantly induced by 0.001 mg l{sup -1} (below the criteria for Chinese fishery water quality) of PCP exposure. A strong positive correlation (r = 0.9581, p < 0.001) was observed between PCP liver concentrations and hydroxyl radical intensities within 7 d of PCP exposure, which suggests that hydroxyl radical are mainly produced from PCP itself. However, no correlation was observed between PCP liver concentrations and hydroxyl radical intensities after 7 d, and a higher intensity of hydroxyl radical could still be observed when the PCP liver concentrations decreased to a lower level, which suggests that other mechanisms may possibly contribute to hydroxyl radical production after 7 d. The glutathione/oxidized glutathione (GSH/GSSG) ratio decreased below that of the control level during the entire period of PCP exposure (0.05 mg l{sup -1}), which suggested oxidative stress occurred.

Organohalogen Compounds in Pet Dog and Cat: Do Pets Biotransform Natural Brominated Products in Food to Harmful Hydroxlated Substances?

Science.gov (United States)

Mizukawa, Hazuki; Nomiyama, Kei; Nakatsu, Susumu; Iwata, Hisato; Yoo, Jean; Kubota, Akira; Yamamoto, Miyuki; Ishizuka, Mayumi; Ikenaka, Yoshinori; Nakayama, Shouta M M; Kunisue, Tatsuya; Tanabe, Shinsuke

2016-01-05

There are growing concerns about the increase in hyperthyroidism in pet cats due to exposure to organohalogen contaminants and their hydroxylated metabolites. This study investigated the blood contaminants polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated derivatives (OH-PCBs, OH-PBDEs, and MeO-PBDEs), in pet dogs and cats. We also measured the residue levels of these compounds in commercially available pet foods. Chemical analyses of PCBs and OH-PCBs showed that the OH-PCB levels were 1 to 2 orders of magnitude lower in cat and dog food products than in their blood, suggesting that the origin of OH-PCBs in pet dogs and cats is PCBs ingested with their food. The major congeners of OH-/MeO-PBDEs identified in both pet food products and blood were natural products (6OH-/MeO-BDE47 and 2'OH-/MeO-BDE68) from marine organisms. In particular, higher concentrations of 6OH-BDE47 than 2'OH-BDE68 and two MeO-PBDE congeners were observed in the cat blood, although MeO-BDEs were dominant in cat foods, suggesting the efficient biotransformation of 6OH-BDE47 from 6MeO-BDE47 in cats. We performed in vitro demethylation experiments to confirm the biotransformation of MeO-PBDEs to OH-PBDEs using liver microsomes. The results showed that 6MeO-BDE47 and 2'MeO-BDE68 were demethylated to 6OH-BDE47 and 2'OH-BDE68 in both animals, whereas no hydroxylated metabolite from BDE47 was detected. The present study suggests that pet cats are exposed to MeO-PBDEs through cat food products containing fish flavors and that the OH-PBDEs in cat blood are derived from the CYP-dependent demethylation of naturally occurring MeO-PBDE congeners, not from the hydroxylation of PBDEs.

Progress modelling of aqueous electrons and hydroxyl radicals in RAIM code

Energy Technology Data Exchange (ETDEWEB)

Kim, A Yeong; Kim, Han-Chul; Lee, Jongseong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-10-15

In this paper, the RAIM code was revised minutely with regards to aqueous electrons and hydroxyl radicals, and simulated the P10T2 test. The recent study indicated that the RAIM had the potential for improvement of simulating the iodine behavior influenced by water radiolysis products such as aqueous electrons and hydroxyl radicals. In the existing RAIM modelling, it was considered that aqueous electrons only interacted with oxygen as a consumption reaction, but the reaction with hydrogen peroxide also could be major contributor to the iodine behavior as well as the consumption reaction of aqueous electrons. In case of hydroxyl radicals, RAIM took no notice of the pH impact. In other words, it dealt with the consumption reaction constants but not as a variable of pH. In this communication, the procedures to develop the model related to aqueous electrons and hydroxyl radicals in RAIM will be addressed. And the upgraded RAIM (RAIM-1, 2, 3) codes were applied to OECD-BIP P10T2 test which showed the effect of pH on the iodine behavior and compared with the existing RAIM1.8.3 code. Comparing with the existing RAIM, the improvement reduced the difference about 10%. However, the absolute difference values that is about one order at pH 10 could not be reduced by this approach.

Modeling 137Cs bioaccumulation in the salmon–resident killer whale food web of the Northeastern Pacific following the Fukushima Nuclear Accident

International Nuclear Information System (INIS)

Alava, Juan José; Gobas, Frank A.P.C.

2016-01-01

To track the long term bioaccumulation of 137 Cs in marine organisms off the Pacific Northwest coast of Canada, we developed a time dependent bioaccumulation model for 137 Cs in a marine mammalian food web that included fish-eating resident killer whales. The model outcomes show that 137 Cs can be expected to gradually bioaccumulate in the food web over time as demonstrated by the increase of the apparent trophic magnification factor of 137 Cs, ranging from 0.76 after 1 month of exposure to 2.0 following 30 years of exposure. 137 Cs bioaccumulation is driven by relatively rapid dietary uptake rates, moderate depuration rates in lower trophic level organisms and slow elimination rates in high trophic level organisms. Model estimates of the 137 Cs activity in species of the food web, based on current measurements and forecasts of 137 Cs activities in oceanic waters and sediments off the Canadian Pacific Northwest, indicate that the long term 137 Cs activities in fish species including Pacific herring, wild Pacific salmon, sablefish and halibut will remain well below the current 137 Cs-Canada Action Level for consumption (1000 Bq/kg) following a nuclear emergency. Killer whales and Pacific salmon are expected to exhibit the largest long term 137 Cs activities and may be good sentinels for monitoring 137 Cs in the region. Assessment of the long term consequences of 137 Cs releases from the Fukushima aftermath should consider the extent of ecological magnification in addition to ocean dilution. - Highlights: • A food web bioaccumulation model to assess the biomagnification of 137 Cs is developed. • Cesium 137 exhibits bioaccumulation over time as simulated by the model. • Predicted activities in marine biota are below 137 Cs-food consumption benchmarks. • Long-term monitoring of 137 Cs in the ocean will improve the model predictions.

Mercury cycling in stream ecosystems. 3. Trophic dynamics and methylmercury bioaccumulation

Science.gov (United States)

Chasar, L.C.; Scudder, B.C.; Stewart, A.R.; Bell, A.H.; Aiken, G.R.

2009-01-01

Trophic dynamics (community composition and feeding relationships) have been identified as important drivers of methylmercury (MeHg) bioaccumulation in lakes, reservoirs, and marine ecosystems. The relative importance of trophic dynamics and geochemical controls on MeHg bioaccumulation in streams, however, remains poorly characterized. MeHg bioaccumulation was evaluated in eight stream ecosystems across the United States (Oregon, Wisconsin, and Florida) spanning large ranges in climate, landscape characteristics, atmospheric Hg deposition, and stream chemistry. Across all geographic regions and all streams, concentrations of total Hg (THg) in top predator fish and forage fish, and MeHg in invertebrates, were strongly positively correlated to concentrations of filtered THg (FTHg), filtered MeHg (FMeHg), and dissolved organic carbon (DOC); to DOC complexity (as measured by specific ultraviolet absorbance); and to percent wetland in the stream basins. Correlations were strongest for nonurban streams. Although regressions of log[Hg] versus ??15N indicate that Hg in biota increased significantly with increasing trophic position within seven of eight individual streams, Hg concentrations in top predator fish (including cutthroat, rainbow, and brown trout; green sunfish; and largemouth bass) were not strongly influenced by differences in relative trophic position. Slopes of log[Hg] versus ??15N, an indicator of the efficiency of trophic enrichment, ranged from 0.14 to 0.27 for all streams. These data suggest that, across the large ranges in FTHg (0.14-14.2 ng L-1), FMeHg (0.023-1.03 ng L-1), and DOC (0.50-61.0 mg L-1) found in this study, Hg contamination in top predator fish in streams likely is dominated by the amount of MeHg available for uptake at the base of the food web rather than by differences in the trophic position of top predator fish. ?? 2009 American Chemical Society.

Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata.

Science.gov (United States)

Li, Shun-Xing; Chen, Li-Hui; Zheng, Feng-Ying; Huang, Xu-Guang

2014-07-23

Oysters (Crassostrea angulata) are often exposed to eutrophication. However, how these exposures influence metal bioaccumulation and oral bioavailability (OBA) in oysters is unknown. After a four month field experimental cultivation, bioaccumulation factors (BAF) of metals (Fe, Cu, As, Cd, and Pb) from seawater to oysters and metal oral bioavailability in oysters by bionic gastrointestinal tract were determined. A positive effect of macronutrient (nitrate N and total P) concentration in seawater on BAF of Cd in oysters was observed, but such an effect was not significant for Fe, Cu, Pb, and As. Only OBA of As was significantly positively correlated to N and P contents. For Fe, OBA was negatively correlated with N. The regular variation of the OBA of Fe and As may be due to the effect of eutrophication on the synthesis of metal granules and heat-stable protein in oysters, respectively.

Bioaccumulation of lead nitrate in freshwater crayfish (Astacus leptodactylus) tissues under aquaculture conditions.

Science.gov (United States)

Naghshbandi, N; Zare, S; Heidari, R; Soleimani Palcheglu, S

2007-09-15

The aim of this research was to evaluate the amount of lead in the tissue of Astacus leptodactylus especially in their muscle which the consumed part of their body. In this study the crayfish was exposed to intermediate concentration of lead nitrate (500 microg L(-1)) for periods up to 3 weeks. In the first, second and third weeks bioaccumulation in various tissues was under investigation. The data of toxicological analysis obtained by the method of atomic absorption revealed that the levels of bioaccumulation of metal are different in various tissues of this crayfish. The accumulation of the lead in gills was the highest and in muscles was lowest degree. The amount of heavy metals in the tissues of crayfish was as follow. Gills>exoskeleton>hepatopancreas (digestive glands)>digestive tract>green gland>testis and ovary>muscles.

Regioselective alkane hydroxylation with a mutant CYP153A6 enzyme

Science.gov (United States)

Koch, Daniel J.; Arnold, Frances H.

2013-01-29

Cytochrome P450 CYP153A6 from Myobacterium sp. strain HXN1500 was engineered using in-vivo directed evolution to hydroxylate small-chain alkanes regioselectively. Mutant CYP153A6-BMO1 selectively hydroxylates butane and pentane at the terminal carbon to form 1-butanol and 1-pentanol, respectively, at rates greater than wild-type CYP153A6 enzymes. This biocatalyst is highly active for small-chain alkane substrates and the regioselectivity is retained in whole-cell biotransformations.

Biosorption of Strontium from Simulated Nuclear Wastewater by Scenedesmus spinosus under Culture Conditions: Adsorption and Bioaccumulation Processes and Models

Science.gov (United States)

Liu, Mingxue; Dong, Faqin; Kang, Wu; Sun, Shiyong; Wei, Hongfu; Zhang, Wei; Nie, Xiaoqin; Guo, Yuting; Huang, Ting; Liu, Yuanyuan

2014-01-01

Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions. PMID:24919131

Biosorption of Strontium from Simulated Nuclear Wastewater by Scenedesmus spinosus under Culture Conditions: Adsorption and Bioaccumulation Processes and Models

Directory of Open Access Journals (Sweden)

Mingxue Liu

2014-06-01

Full Text Available Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions.

Bioaccumulation and excretion of enantiomers of myclobutanil in Tenebrio molitor larvae through dietary exposure.

Science.gov (United States)

Lv, Xiaotian; Liu, Chen; Li, Yaobin; Gao, Yongxin; Guo, Baoyuan; Wang, Huili; Li, Jianzhong

2013-12-01

The bioaccumulation and excretion of enantiomers of myclobutanil in Tenebrio molitor larvae through dietary exposure under laboratory conditions were investigated using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) based on a ChiralcelOD-3R [cellulosetris-tris-(3, 5-dichlorophenyl-carbamate)] column. The wheat bran fed to Tenebrio molitor larvae was spiked with racemic myclobutanil at two dose levels of 20 mg/kg and 2 mg/kg (dry weight). The results showed that there was a significant trend of enantioselective bioaccumulation in the larvae with a preferential accumulation of (-)-myclobutanil in 20 mg/kg dose exposure, but it was not obviously observed in the 2 mg/kg dose group. A kinetic model considering enantiomerization between the two enantiomers based on first-order reactions was built and the rate constants were estimated to discuss the kinetic reason for the different concentrations of individual enantiomers in the larvae. The approximations implied an inversion between the two enantiomers with a relatively higher rate of the inversion from (-)-myclobutanil to (+)-myclobutanil. Meanwhile, analysis of data of excretion samples suggested the active excretion is probably an important pathway for the insect to eliminate myclobutanil rapidly with nonenantioselectivity as a passive transport process, which was consistent with the low accumulation efficiency of myclobutanil measured by BAF (bioaccumulation factor). © 2013 Wiley Periodicals, Inc.

Methylmercury cycling, bioaccumulation, and export from agricultural and non-agricultural wetlands in the Yolo Bypass

Science.gov (United States)

Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark; Fleck, Jacob; Alpers, Charles N.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Stricker, Craig; Stephenson, Mark; Feliz, David; Gill, Gary; Bachand, Philip; Brice, Ann; Kulakow, Robin

2010-01-01

This 18-month field study addresses the seasonal and spatial patterns and processes controlling methylmercury (MeHg) production, bioaccumulation, and export from natural and agricultural wetlands of the Yolo Bypass Wildlife Area (YBWA). The data were collected in conjuntion with a Proposition 40 grant from the State Water Resources Control Board in support of the development of Best Management Practices (BMP's) for reducing MeHg loading from agricultural lands in the wetland-dominated Yolo Bypass to the Sacramento-San Joaquin River Delta. The four managemenr-based questions addressed in this study were: 1. Is there a different among agricultural and managfed wetland types in terms of Me Hg dynamic (production, degradation, bioaccumulation, or export)?

Novel denture-cleaning system based on hydroxyl radical disinfection.

Science.gov (United States)

Kanno, Taro; Nakamura, Keisuke; Ikai, Hiroyo; Hayashi, Eisei; Shirato, Midori; Mokudai, Takayuki; Iwasawa, Atsuo; Niwano, Yoshimi; Kohno, Masahiro; Sasaki, Keiichi

2012-01-01

The purpose of this study was to evaluate a new denture-cleaning device using hydroxyl radicals generated from photolysis of hydrogen peroxide (H2O2). Electron spin resonance analysis demonstrated that the yield of hydroxyl radicals increased with the concentration of H2O2 and light irradiation time. Staphylococcus aureus, Pseudomonas aeruginosa, and methicillin-resistant S aureus were killed within 10 minutes with a > 5-log reduction when treated with photolysis of 500 mM H2O2; Candida albicans was killed within 30 minutes with a > 4-log reduction with photolysis of 1,000 mM H2O2. The clinical test demonstrated that the device could effectively reduce microorganisms in denture plaque by approximately 7-log order within 20 minutes.

Lettuce irrigated with contaminated water: Photosynthetic effects, antioxidative response and bioaccumulation of microcystin congeners.

Science.gov (United States)

Bittencourt-Oliveira, Maria do Carmo; Cordeiro-Araújo, Micheline Kézia; Chia, Mathias Ahii; Arruda-Neto, João Dias de Toledo; de Oliveira, Ênio Tiago; dos Santos, Flávio

2016-06-01

The use of microcystins (MCs) contaminated water to irrigate crop plants represents a human health risk due to their bioaccumulation potential. In addition, MCs cause oxidative stress and negatively influence photosynthetic activities in plants. The present study was aimed at investigating the effect of MCs on photosynthetic parameters and antioxidative response of lettuce. Furthermore, the bioaccumulation factor (BAF) of total MCs, MC-LR and MC-RR in the vegetable after irrigation with contaminated water was determined. Lettuce crops were irrigated for 15 days with water containing cyanobacterial crude extracts (Microcystis aeruginosa) with MC-LR (0.0, 0.5, 2.0, 5.0 and 10.0 µg L(-1)), MC-RR (0.0, 0.15, 0.5, 1.5 and 3.0 µg L(-1)) and total MCs (0.0, 0.65, 2.5, 6.5 and 13.0 µg L(-1)). Increased net photosynthetic rate, stomatal conductance, leaf tissue transpiration and intercellular CO2 concentration were recorded in lettuce exposed to different MCs concentrations. Antioxidant response showed that glutathione S-transferase activity was down-regulated in the presence of MCs. On the other hand, superoxide dismutase, catalase and peroxidase activities were upregulated with increasing MCs concentrations. The bioaccumulation factor (BAF) of total MCs and MC-LR was highest at 6.50 and 5.00 µg L(-1), respectively, while for MC-RR, the highest BAF was recorded at 1.50 µg L(-1) concentration. The amount of total MCs, MC-LR and MC-RR bioacumulated in lettuce was highest at the highest exposure concentrations. However, at the lowest exposure concentration, there were no detectable levels of MC-LR, MC-RR and total MCs in lettuce. Thus, the bioaccumulation of MCs in lettuce varies according to the exposure concentration. In addition, the extent of physiological response of lettuce to the toxins relies on exposure concentrations. Copyright © 2016 Elsevier Inc. All rights reserved.

Environmental contaminants in arctic foxes (Alopex lagopus) in Svalbard: Relationships with feeding ecology and body condition

Energy Technology Data Exchange (ETDEWEB)

Fuglei, E. [Norwegian Polar Institute, Polar Environmental Centre, N-9296 Tromso (Norway)]. E-mail: eva.fuglei@npolar.no; Bustnes, J.O. [Norwegian Institute for Nature Research, Division of Arctic Ecology, Polar Environmental Centre, N-9296 Tromso (Norway); Hop, H. [Norwegian Polar Institute, The Polar Environmental Centre, N-9296 Tromso (Norway); Mork, T. [National Veterinary Institute, Regional Laboratory, N-9292 Tromso (Norway); Bjoernfoth, H. [MTM Research Centre, Department of Natural Sciences, Orebro University, 701 82 Orebro (Sweden); Bavel, B. van [MTM Research Centre, Department of Natural Sciences, Orebro University, 701 82 Orebro (Sweden)

2007-03-15

Adipose tissues from 20 arctic foxes (Alopex lagopus) of both sexes from Svalbard were analysed for polybrominated diphenyl ether (PBDE), polychlorinated biphenyl (PCB), p,p'-dichlorodiphenyltrichloroethane (DDE), chlordane, and hexachlorobenzene (HCB) concentrations. Gender (0.43 < p < 0.97) and age (0.15 < p < 0.95) were not significantly related to any of the organohalogen groups. Body condition showed a significant inverse relationship with {sigma}PBDE, {sigma}Chlordane and HCB, suggesting that increased tissue contaminant concentrations are associated with depletion of adipose tissue. The seasonal cyclic storage and mobilisation of adipose tissue, characteristic in Arctic wildlife, may then provide increased input of contaminants to sensitive, vital effect organs. Trophic position was estimated by {delta} {sup 15}N from muscle samples and showed significantly positive relationship with all contaminants, with the exception of HCB concentrations. This indicates that foxes feeding at high trophic levels had higher tissue contaminant levels as a result of bioaccumulation in the food chain. - High contaminant concentrations in the coastal ecotype of arctic fox may cause toxic health effects due to huge annual cyclic variation in storage and mobilisation of adipose tissue.

Steroid hydroxylations: A paradigm for cytochrome P450 catalyzed mammalian monooxygenation reactions

International Nuclear Information System (INIS)

Estabrook, Ronald W.

2005-01-01

The present article reviews the history of research on the hydroxylation of steroid hormones as catalyzed by enzymes present in mammalian tissues. The report describes how studies of steroid hormone synthesis have played a central role in the discovery of the monooxygenase functions of the cytochrome P450s. Studies of steroid hydroxylation reactions can be credited with showing that: (a) the adrenal mitochondrial enzyme catalyzing the 11β-hydroxylation of deoxycorticosterone was the first mammalian enzyme shown by O 18 studies to be an oxygenase; (b) the adrenal microsomal enzyme catalyzing the 21-hydroxylation of steroids was the first mammalian enzyme to show experimentally the proposed 1:1:1 stoichiometry (substrate:oxygen:reduced pyridine nucleotide) of a monooxygenase reaction; (c) application of the photochemical action spectrum technique for reversal of carbon monoxide inhibition of the 21-hydroxylation of 17α-OH progesterone was the first demonstration that cytochrome P450 was an oxygenase; (d) spectrophotometric studies of the binding of 17α-OH progesterone to bovine adrenal microsomal P450 revealed the first step in the cyclic reaction scheme of P450, as it catalyzes the 'activation' of oxygen in a monooxygenase reaction; (e) purified adrenodoxin was shown to function as an electron transport component of the adrenal mitochondrial monooxygenase system required for the activity of the 11β-hydroxylase reaction. Adrenodoxin was the first iron-sulfur protein isolated and purified from mammalian tissues and the first soluble protein identified as a reductase of a P450; (f) fractionation of adrenal mitochondrial P450 and incubation with adrenodoxin and a cytosolic (flavoprotein) fraction were the first demonstration of the reconstitution of a mammalian P450 monooxygenase reaction

Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

Directory of Open Access Journals (Sweden)

Béla Fiser

Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

Effects of microplastic on fitness and PCB bioaccumulation by the lugworm Arenicola marina

NARCIS (Netherlands)

Besseling, E.; Wegner, A.; Foekema, E.M.; Heuvel_Greve, van den M.J.; Koelmans, A.A.

2013-01-01

It has been speculated that marine microplastics may cause negative effects on benthic marine organisms and increase bioaccumulation of persistent organic pollutants (POPs). Here, we provide the first controlled study of plastic effects on benthic organisms including transfer of POPs. The effects of

Heavy metal bioaccumulation by the important food plant, olea europaea L., in an ancient metalliferous polluted area of Cyprus

OpenAIRE

Wilson, B; Pyatt, FB

2007-01-01

Aspects of the bioaccumulation of heavy metals are reviewed and possible evidence of homeostasis is highlighted. Examination and analysis of olive (Olea europaea L.) trees growing in close proximity to a copper dominated spoil tip dating from at least 2000 years BP, on the island of Cyprus, revealed both bioaccumulation and partitioning of copper, lead and zinc in various parts of the tree. A factor to quantify the degree of accumulation is illustrated and a possible seed protective mechanism...

Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

Energy Technology Data Exchange (ETDEWEB)

Tu, Tengxiu [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Li, Shunxing, E-mail: lishunxing@mnnu.edu.cn [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China); Chen, Lihui [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Zheng, Fengying; Huang, Xu-Guang [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China)

2014-10-15

Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams.

Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

International Nuclear Information System (INIS)

Tu, Tengxiu; Li, Shunxing; Chen, Lihui; Zheng, Fengying; Huang, Xu-Guang

2014-01-01

Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams

Bioaccumulation and biomagnification of short and medium chain polychlorinated paraffins in different species of fish from Liaodong Bay, North China

OpenAIRE

Huang, Huiting; Gao, Lirong; Xia, Dan; Qiao, Lin

2017-01-01

Chlorinated paraffins (CPs) are highly complex technical mixtures, and the short chain chlorinated paraffins (SCCPs) are classed as persistent and have been included in the Stockholm Convention. However, there have been few studies of SCCPs and medium chain chlorinated paraffins (MCCPs) and their bioaccumulation and biomagnification in different species of fish. The present study investigated the levels, congener group profiles, bioaccumulation, and biomagnification of SCCPs and MCCPs in diff...

Exposure assessment of French women and their newborn to brominated flame retardants: Determination of tri- to deca- polybromodiphenylethers (PBDE) in maternal adipose tissue, serum, breast milk and cord serum

International Nuclear Information System (INIS)

Antignac, Jean-Philippe; Cariou, Ronan; Zalko, Daniel; Berrebi, Alain; Cravedi, Jean-Pierre; Maume, Daniel; Marchand, Philippe; Monteau, Fabrice; Riu, Anne; Andre, Francois; Le Bizec, Bruno

2009-01-01

In the frame of a French monitoring program, tri- to deca- polybromodiphenylethers (PBDE) have been measured in maternal and cord serum, adipose tissue, and breast milk samples, collected from 93 volunteer women during caesarean deliveries. The seven major tri- to heptaBDE (BDE-28, 47, 99, 100, 153, 154, and 183) were detected in adipose tissue and breast milk with cumulated median values of 2.59 and 2.51 ng g -1 l w. Nine highly brominated octa- to decaBDE (BDE-196, 197, 201, 202, 203, 206, 207, 208 and 209) was performed in the same samples, with cumulated median values of 2.73 and 3.39 ng g -1 l w in adipose tissue and breast milk, respectively. At this opposite, median levels of octa- to decaBDE in maternal and cord serum appeared significantly higher than the levels of tri- to heptaBDE in the same matrices, i.e. 8.85 and 12.34 versus 0.98 and 0.69 ng g -1 l w, respectively. - This study provides the first data at the French level regarding the occurrence of PBDE in human, and demonstrates the exposure of both human foetus at late stage of pregnancy and newborn at early stages of life through breastfeeding with special emphasis on the presence of highly brominated compounds

Exposure assessment of French women and their newborn to brominated flame retardants: Determination of tri- to deca- polybromodiphenylethers (PBDE) in maternal adipose tissue, serum, breast milk and cord serum

Energy Technology Data Exchange (ETDEWEB)

Antignac, Jean-Philippe [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France)], E-mail: antignac@vet-nantes.fr; Cariou, Ronan [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France); Zalko, Daniel [UMR 1089 Xenobiotiques, INRA, 31931 Toulouse (France); Berrebi, Alain [Centre Hospitalier Universitaire de Toulouse, Hopital Paule de Viguier, Service de gynecologie-obstetrique, Toulouse (France); Cravedi, Jean-Pierre [UMR 1089 Xenobiotiques, INRA, 31931 Toulouse (France); Maume, Daniel; Marchand, Philippe; Monteau, Fabrice [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France); Riu, Anne [Unite Signalisation Hormonale, Environnement et Cancer, U824 INSERM, 34298 Montpellier Cedex 5 (France); Andre, Francois; Le Bizec, Bruno [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France)

2009-01-15

In the frame of a French monitoring program, tri- to deca- polybromodiphenylethers (PBDE) have been measured in maternal and cord serum, adipose tissue, and breast milk samples, collected from 93 volunteer women during caesarean deliveries. The seven major tri- to heptaBDE (BDE-28, 47, 99, 100, 153, 154, and 183) were detected in adipose tissue and breast milk with cumulated median values of 2.59 and 2.51 ng g{sup -1} l w. Nine highly brominated octa- to decaBDE (BDE-196, 197, 201, 202, 203, 206, 207, 208 and 209) was performed in the same samples, with cumulated median values of 2.73 and 3.39 ng g{sup -1} l w in adipose tissue and breast milk, respectively. At this opposite, median levels of octa- to decaBDE in maternal and cord serum appeared significantly higher than the levels of tri- to heptaBDE in the same matrices, i.e. 8.85 and 12.34 versus 0.98 and 0.69 ng g{sup -1} l w, respectively. - This study provides the first data at the French level regarding the occurrence of PBDE in human, and demonstrates the exposure of both human foetus at late stage of pregnancy and newborn at early stages of life through breastfeeding with special emphasis on the presence of highly brominated compounds.

V color centers in electrolytically colored hydroxyl-doped sodium chloride crystals

International Nuclear Information System (INIS)

Gu Hongen; Song Cuiying; Han Li

2006-01-01

Hydroxyl-doped sodium chloride crystals were successfully colored electrolytically by using pointed anode and flat cathode at various temperatures and under various electric field strengths. V 2 and V 3 color centers were produced in the colored crystals. Current-time curves for the electrolytic colorations were given, and activation energy for the V 2 and V 3 color center migration was determined. Production of the V 2 and V 3 color centers and formation of current zones for the electrolytic colorations of the hydroxyl-doped sodium chloride crystals are explained

Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural soil

DEFF Research Database (Denmark)

Rønhede, S.; Jensen, Bo; Rosendahl, Søren

2005-01-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N......Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl...

Impact of humic substances on the aqueous solubility, uptake and bioaccumulation of platinum, palladium and rhodium in exposure studies with Dreissena polymorpha

Energy Technology Data Exchange (ETDEWEB)

Sures, Bernd [Department of Applied Zoology/Hydrobiology, University of Duisburg-Essen, D-45177 Essen (Germany)]. E-mail: bernd.sures@uni-due.de; Zimmermann, Sonja [Department of Applied Zoology/Hydrobiology, University of Duisburg-Essen, D-45177 Essen (Germany)

2007-03-15

Zebra mussels (Dreissena polymorpha) were exposed to different types of water containing PGE salts (PtCl{sub 4}, PdSO{sub 4}, RhCl{sub 3}) to investigate the influence of humic substances on the aqueous solubility, uptake and bioaccumulation of noble metals. The results showed a time dependent decrease of the aqueous PGE concentrations in tank water for all groups. This could mainly be related to non-biological processes. The aqueous solubility of Pd and Rh was higher in humic water compared with non-chlorinated tap water, whereas Pt showed opposing results. Highest metal uptake rates and highest bioaccumulation plateaus were found for Pd, followed by Pt and Rh. Pd uptake and bioaccumulation was significantly hampered by humic substances, whose presence appear to increase Pt uptake and bioaccumulation. No clear trend emerged for Rh. Differences in effects of humic matter among the PGE may be explained by formation of metal complexes with different fractions of humic substances. - Precious metal accumulation in Dreissena polymorpha is affected by humic substances.

Enantiomerization and enantioselective bioaccumulation of benalaxyl in Tenebrio molitor larvae from wheat bran.

Science.gov (United States)

Gao, Yongxin; Chen, Jinhui; Wang, Huili; Liu, Chen; Lv, Xiaotian; Li, Jianzhong; Guo, Baoyuan

2013-09-25

The enantiomerization and enatioselecive bioaccumulation of benalaxyl by dietary exposure to Tenebrio molitor larvae under laboratory conditions were studied by HPLC-MS/MS. Exposure of enantiopure R-benalaxyl and S-benalaxyl in T. molitor larvae revealed significant enantiomerization with formation of the R enantiomers from the S enantiomers, and vice versa. Enantiomerization was not observed in wheat bran during the period of 21 days. For the bioaccumulation experiment, the enantiomer fraction in T. molitor larvae was maintained approximately at 0.6, whereas the enantiomer fraction in wheat bran was maintained at 0.5; in other words, the bioaccumulation of benalaxyl was enantioselective in T. molitor larvae. Mathematical models for a process of uptake, degradation, and enantiomerization were developed, and the rates of uptake, degradation, and enantiomerization of R-benealaxyl and S-benealaxyl were estimated, respectively. The results were that the rate of uptake of R-benalaxyl (kRa = 0.052 h(-1)) was slightly lower than that of S-benalaxyl (kSa = 0.061 h(-1)) from wheat bran; the rate of degradation of R-benalaxyl (kRd = 0.285 h(-1)) was higher than that of S-benalaxyl (kSd = 0.114 h(-1)); and the rate of enantiomerization of R-benalaxyl (kRS = 0.126 h(-1)) was higher than that of S-benalaxyl (kSR = 0.116 h(-1)). It was suggested that enantioselectivtiy was caused not only by actual degradation and metabolism but also by enantiomerization, which was an important process in the environmental fate and behavior of chiral pesticides.

Presence of polybrominated diphenyl ethers in Spanish sewage sludges. Important contribution of deca-BDE

Energy Technology Data Exchange (ETDEWEB)

Fabrellas, B.; Larrazabal, D.; Martinez, M.A. [CIEMAT, Madrid (Spain); Eljarrat, E.; Barcelo, D. [I.I.Q.A.B., C.S.I.C, Barcelona (Spain)

2004-09-15

Introduction Polybrominated diphenyl ethers (PBDE) are a family of synthetic chemicals widely used in industry to delay, inhibit or even suppress combustion process in manufactured items. Flame retardant products are frequently added into plastic, electronic, paint and textile materials to reduce the risk of ignition. During last years, increasing levels of PBDE have been detected in the environment, suggesting release from the treated surface as main pathway for environmental intake. Their physicochemical structure make them substances of highly lypophylic, bioaccumulative and persistent nature, with potential toxic effects observed onto wildlife and humans. Some European countries (Switzerland and Sweden) have promoted strategies to enlarge the knowledge of PBDE, in particular their occurrence and levels on sewage sludge. Observations point domestic washing of garment/clothes and industrial discharges from plastic and textile manufacture industry as major sources of contamination. First European results from 1988 revealed levels of about 20-30 {mu}g/kg dw of PBDEs (BDEs 47, 99 and 100) in sludge samples collected in Sweden. More recently, another Swedish survey conducted on three waste-water treatment facilities pointed levels of PBDE (BDE 47, 99 and 209) of about 200 ng/g dw, along with minor contribution of other contaminants such as TBBPA and HBCD iv. Few studies have been carried out in US. Hale et al. compared levels of Tetra-, PentaBDE (BDE 47, BDE 99 and BDE 100) and DecaBDE 209 congeners in sludge from different US locations. Values ranged from 1000 to 2290 {mu}g/kg dw (Tri- to HexaBDE) and from 84 to 4890 {mu}g/kg dw for DecaBDE 209, with mean values of about 1600 and 1000 {mu}g/kg dw, respectively. In general, concentrations of BDE 47, 99, 100 and 209 exceeded those of the major PCB congeners and other halogenated contaminants also found in the sludge. Following this trend, this work aims a preliminary assessment of selected PBDE congener levels on

Retracted: Long-term copper toxicity in apple trees (Malus pumila Mill) and bioaccumulation in fruits.

Science.gov (United States)

Sun, Bai-Ye; Kan, Shi-Hong; Zhang, Yan-Zong; Wu, Jun; Deng, Shi-Huai; Liu, Chun-Sheng; Yang, Gang

2010-01-15

The following article from Environmental Toxicology, 'Long-term Copper Toxicity in Apple Trees (Malus pumila Mill) and Bioaccumulation in Fruits' by Bai-Ye Sun, Shi- Hong Kan, Yan-Zong Zhang, Jun Wu, Shi-Huai Deng, Chun-Sheng Liu and Gang Yang, published online on January 15, 2010 in Wiley InterScience (www.interscience.wiley.com; DOI: 10.1002/tox.20565), has been retracted by agreement between the authors, the journal Editor in Chief, Dr. Paul Tchounwou, and Wiley Periodicals, Inc. The retraction has been agreed at the request of the authors due to overlap with 'Copper Toxicity and Bioaccumulation in Chinese Cabbage (Brassica pekinensis Rupr.)' by Zhi-Ting Xiong and Hai Wang, published in Environmental Toxicology, Volume 20, pages 188-194, 2005.

Coupling marine monitoring and risk assessment by integrating exposure, bioaccumulation and effect studies

DEFF Research Database (Denmark)

Strand, J.

This Ph.D. thesis focuses on the highly toxic organotin compounds, mainly tri-n-butyltin (TBT) but also triphenyltin (TPhT), which have been widely used as antifouling agents in ship paints, and covers several aspects investigated by field studies of spatial distributions, bioaccumulation...

Modeling the thermostability of surface functionalisation by oxygen, hydroxyl, and water on nanodiamonds.

Science.gov (United States)

Lai, Lin; Barnard, Amanda S

2011-06-01

Understanding nanodiamond functionalisation is of great importance for biological and medical applications. Here we examine the stabilities of oxygen, hydroxyl, and water functionalisation of the nanodiamonds using the self-consistent charge density functional tight-binding simulations. We find that the oxygen and hydroxyl termination are thermodynamically favourable and form strong C–O covalent bonds on the nanodiamond surface in an O2 and H2 gas reservoir, which confirms previous experiments. Yet, the thermodynamic stabilities of oxygen and hydroxyl functionalisation decrease dramatically in a water vapour reservoir. In contrast, H2O molecules are found to be physically adsorbed on the nanodiamond surface, and forced chemical adsorption results in decomposition of H2O. Moreover, the functionalisation efficiency is found to be facet dependent. The oxygen functionalisation prefers the {100} facets as opposed to alternative facets in an O2 and H2 gas reservoir. The hydroxyl functionalisation favors the {111} surfaces in an O2 and H2 reservoir and the {100} facets in a water vapour reservoir, respectively. This facet selectivity is found to be largely dependent upon the environmental temperature, chemical reservoir, and morphology of the nanodiamonds.

Electrolytic coloration and spectral properties of hydroxyl-doped potassium chloride single crystals

International Nuclear Information System (INIS)

Gu Hongen; Wu Yanru

2011-01-01

Hydroxyl-doped potassium chloride single crystals are colored electrolytically at various temperatures and voltages using a pointed cathode and a flat anode. Characteristic OH - spectral band is observed in the absorption spectrum of uncolored single crystal. Characteristic O - , OH - , U, V 2 , V 3 , O 2- -V a + , F, R 2 and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current-time curve for electrolytic coloration of hydroxyl-doped potassium chloride single crystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained. - Highlights: → Expanded the traditional electrolysis method. → Hydroxyl-doped potassium chloride crystals were colored electrolytically for the first time. → Useful V, F and F-aggregate color centers were produced in colored crystals. → V color centers were produced directly and F and F-aggregate color centers indirectly.

Heavy metal bioaccumulation by the important food plant, Olea europaea L., in an ancient metalliferous polluted area of Cyprus.

Science.gov (United States)

Wilson, B; Pyatt, F B

2007-05-01

Aspects of the bioaccumulation of heavy metals are reviewed and possible evidence of homeostasis is highlighted. Examination and analysis of olive (Olea europaea L.) trees growing in close proximity to a copper dominated spoil tip dating from at least 2000 years BP, on the island of Cyprus, revealed both bioaccumulation and partitioning of copper, lead and zinc in various parts of the tree. A factor to quantify the degree of accumulation is illustrated and a possible seed protective mechanism suggested.

FIH Regulates Cellular Metabolism through Hydroxylation of the Deubiquitinase OTUB1.

Directory of Open Access Journals (Sweden)

Carsten C Scholz

2016-01-01

Full Text Available The asparagine hydroxylase, factor inhibiting HIF (FIH, confers oxygen-dependence upon the hypoxia-inducible factor (HIF, a master regulator of the cellular adaptive response to hypoxia. Studies investigating whether asparagine hydroxylation is a general regulatory oxygen-dependent modification have identified multiple non-HIF targets for FIH. However, the functional consequences of this outside of the HIF pathway remain unclear. Here, we demonstrate that the deubiquitinase ovarian tumor domain containing ubiquitin aldehyde binding protein 1 (OTUB1 is a substrate for hydroxylation by FIH on N22. Mutation of N22 leads to a profound change in the interaction of OTUB1 with proteins important in cellular metabolism. Furthermore, in cultured cells, overexpression of N22A mutant OTUB1 impairs cellular metabolic processes when compared to wild type. Based on these data, we hypothesize that OTUB1 is a target for functional hydroxylation by FIH. Additionally, we propose that our results provide new insight into the regulation of cellular energy metabolism during hypoxic stress and the potential for targeting hydroxylases for therapeutic benefit.

- Hydroxylated Anthraquinones Produced by Geosmithia species

Czech Academy of Sciences Publication Activity Database

Stodůlková, Eva; Kolařík, Miroslav; Křesinová, Zdena; Kuzma, Marek; Šulc, Miroslav; Man, Petr; Novák, Petr; Maršík, Petr; Landa, Přemysl; Olšovská, Jana; Chudíčková, Milada; Pažoutová, Sylvie; Černý, J.; Bella, J.; Flieger, Miroslav

2009-01-01

Roč. 54, č. 3 (2009), s. 179-187 ISSN 0015-5632 R&D Projects: GA AV ČR KAN200200651; GA MŠk LC07017; GA MŠk 1M0506; GA ČR GP203/05/P575 Grant - others:CZ(CZ) 205/2004 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50380511 Keywords : hydroxylated anthraquinones * staphylococcus aureus * mammalian cell lines Subject RIV: EE - Microbiology, Virology Impact factor: 0.978, year: 2009

Assessment of metals bioaccumulation and bioavailability in mussels Mytilus galloprovincialis exposed to outfalls pollution in coastal areas of Casablanca.

Science.gov (United States)

Mejdoub, Zineb; Zaid, Younes; Hmimid, Fouzia; Kabine, Mostafa

2018-07-01

The present work aims to study the metallic contamination of four sampling sites located nearby major sewage outfalls of the Casablanca coast (Morocco), using indigenous mussels Mytilus galloprovincialis as bioindicators of pollution. This research offered the opportunity to study trace metals bioaccumulation mechanisms, which represent a major factor in assessment processes of the pollution effects in coastal ecosystem health. The bioavailability and the bioaccumulation of trace metals (Cu, Zn, Ni, Pb) were evaluated in order to compare the metallic contamination in mussels' tissues and find a possible correlation with physiological parameters of this filter feeding species. Our results showed a significant spatiotemporal variation of bioaccumulation, compared to control. A significant correlation coefficient between metals (Zn and Pb) bioavailability and physiological index (CI) was revealed in mussels from the most polluted location. The seasonal variation of trace metal accumulation was also raised; the highest values recorded during the dry period. Copyright © 2018 Elsevier GmbH. All rights reserved.

Bioaccumulation of 137Cs in pelagic food webs in the Norwegian and Barents Seas

International Nuclear Information System (INIS)

Heldal, Hilde Elise; Foeyn, Lars; Varskog, Per

2003-01-01

Knowledge and documentation of the levels of radioactive contamination in fish stocks important to Norwegian fisheries is of major importance to Norwegian consumers and fish export industry. In the present study, the bioaccumulation of caesium-137 ( 137 Cs) has been investigated in marine food webs in the Barents and Norwegian Seas. The contents of 137 Cs in the different organisms were generally low ( -1 wet weight), but a marked bioaccumulation was apparent: The concentration of 137 Cs was about 10-fold higher in the harbour porpoise Phocoena phocoena, representing the upper level of the food web, than in the amphipod Themisto sp., representing the lower level of the food web. The Concentration Factors (CF=Bq kg -1 wet weight/Bq l -1 seawater) increased from 10±3 for a mixed sample of krill and amphipods to 165±5 for harbour porpoises

Hydrotreating of compounds and mixtures of compounds having mercapto and hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Viljava, T.R.; Krause, A.O.I. [Helsinki University of Technology, Espoo (Finland)

1997-07-01

Simultaneous hydrodesulfurization (HDS) and hydrodeoxygenation (HDO) of mercapto and hydroxyl group containing benzenes was studied using a commercial presulfided CoMo/{gamma}- Al{sub 2}O{sub 3} catalyst under hydrotreating conditions (150-280 deg C, 7 MPa). Mercaptobenzene, phenol and 4-mercaptophenol were used as model compounds, and CS{sub 2} was used as precursor for H{sub 2}S. The HDS rate of a mercapto group in the presence of a hydroxyl substituent in the para position was higher than that for the molecule containing only a mercapto group. When the hydroxyl group was present as phenol, the HDS rate of the mercapto group was about 30% lower than that for mercaptobenzene without an oxygen-containing additive. The decrease in the HDS rate was independent of the initial molar ratio of sulfur and oxygen within the ratios studied (5:1-1:1). The HDO rate of a hydroxyl group was suppressed by the mercapto group present either in the same or in a separate molecule. HDO reactions did not start until HDS conversion was almost complete. CS{sub 2} also decreased the HDO rate of phenol. When compared to the reactions of phenol alone, the rate of the hydrogenolysis route to benzene was decreased in the presence of a sulfur additive more than the hydrogenolysis- hydrogenation route to cyclohexane. 19 refs.

Bioaccumulation of perfluoroalkyl acids by earthworms (Eisenia fetida) exposed to contaminated soils.

Science.gov (United States)

Rich, Courtney D; Blaine, Andrea C; Hundal, Lakhwinder; Higgins, Christopher P

2015-01-20

The presence of perfluoroalkyl acids (PFAAs) in biosolids-amended and aqueous film-forming foam (AFFF)-impacted soils results in two potential pathways for movement of these environmental contaminants into terrestrial foodwebs. Uptake of PFAAs by earthworms (Eisenia fetida) exposed to unspiked soils with varying levels of PFAAs (a control soil, an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and two AFFF-impacted soils) was measured. Standard 28 day exposure experiments were conducted in each soil, and measurements taken at additional time points in the municipal soil were used to model the kinetics of uptake. Uptake and elimination rates and modeling suggested that steady state bioaccumulation was reached within 28 days of exposure for all PFAAs. The highest concentrations in the earthworms were for perfluorooctane sulfonate (PFOS) in the AFFF-impacted Soil A (2160 ng/g) and perfluorododecanoate (PFDoA) in the industrially impacted soil (737 ng/g). Wet-weight (ww) and organic carbon (OC)-based biota soil accumulation factors (BSAFs) for the earthworms were calculated after 28 days of exposure for all five soils. The highest BSAF in the industrially impacted soil was for PFDoA (0.42 goc/gww,worm). Bioaccumulation factors (BAFs, dry-weight-basis, dw) were also calculated at 28 days for each of the soils. With the exception of the control soil and perfluorodecanoate (PFDA) in the industrially impacted soil, all BAF values were above unity, with the highest being for perfluorohexanesulfonate (PFHxS) in the AFFF-impacted Soil A (139 gdw,soil/gdw,worm). BSAFs and BAFs increased with increasing chain length for the perfluorocarboxylates (PFCAs) and decreased with increasing chain length for the perfluoroalkyl sulfonates (PFSAs). The results indicate that PFAA bioaccumulation into earthworms depends on soil concentrations, soil characteristics, analyte, and duration of exposure, and that accumulation into earthworms may be a potential

Levels and bioaccumulation of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in fishes from the Pearl River estuary and Daya Bay, South China

International Nuclear Information System (INIS)

Guo Lingli; Qiu Yaowen; Zhang Gan; Zheng, Gene J.; Lam, Paul K.S.; Li Xiangdong

2008-01-01

Fifty fish samples were collected from the Pearl River estuary (PRE) and Daya Bay, South China and were analyzed for DDTs, HCHs, chlordanes and polybrominated biphenyl ethers (PBDEs). Except the high concentrations of DDT observed in fishes, the concentrations of HCHs, chlordanes and PBDEs were low when compared to other regions. BDE-47 was the predominant PBDE congener and the BDE-209 concentrations were relatively low, despite its high concentration in surface sediments. The absence of significant increase of DDT, HCH, chlordane and PBDE concentrations towards higher δ 15 N values, as well as the lack of a significant correlation (p 15 N, may indicate a weak biomagnification of these chemicals in the food webs. Good agreement was observed between their concentrations and lipid contents of the organisms. Bioconcentration was suggested to be responsible for the accumulation of OCPs and PBDEs in the lower trophic organisms in the studied subtropical waters. - Bioconcentration was suggested to be responsible for the accumulation of OCPs and PBDEs in the lower trophic organisms of subtropical waters

Bioaccumulation of selenium and induced biological effects in the filter feeding bivalve Corbicula fluminea: influence of ventilatory activity, selenium speciation and route of transfer

International Nuclear Information System (INIS)

Fournier, E.

2005-10-01

Selenium is an essential micro-nutrient for most of living organisms. However, toxic effects in several ecosystems have been reported in the literature. Toxicity comprehension is difficult due to the complexity of Se oxidation states in the environment. The aim of this thesis work was to acquire knowledge on the physiological and environmental factors involved in bioaccumulation and toxicity processes in the freshwater filter-feeding bivalve C. fluminea. The aims were: i) to define what the factors involved in Se bioaccumulation processes in the bivalve are, ii) to characterize Se bioaccumulation at different biological organisation levels, iii) to investigate Se toxic effects. First experiments, carried out for short term exposure duration (3 days), have permitted to underline the importance of Se chemical speciation in bioaccumulation processes in C. fluminea. It has been shown that the organic form, seleno-methionine, was much more bio-available than the inorganic forms, selenite and selenate. Moreover, the route of transfer was determinant in those processes. Inorganic forms have been better extracted by trophic route, whereas seleno-methionine has been better extracted by the direct route. In our experimental conditions, ventilation of the bivalve has not been a limiting factor for Se bioaccumulation by the direct route, whereas it has been for bioaccumulation by the trophic route. Ventilation has been largely modified by the presence of dissolved selenite and seleno-methionine. We have shown that the kinetics of seleno-methionine bioaccumulation are much more fast than those of selenite. Moreover, when introduced as SeMet, internalized Se appeared to be relatively remanent in soft tissues of C. fluminea in comparison with Se internalized when introduced as selenite. Subcellular and molecular distributions of these forms were very different. Finally, it has been shown that seleno-methionine and selenite could generate weak alterations of the anti

Bioaccumulation of perfluoroalkyl carboxylates (PFCAs) and perfluoroalkane sulfonates (PFSAs) by earthworms (Eisenia fetida) in soil

International Nuclear Information System (INIS)

Zhao, Shuyan; Zhu, Lingyan; Liu, Li; Liu, Zhengtao; Zhang, Yahui

2013-01-01

Earthworms were exposed to artificially contaminated soils with ten perfluoroalkyl substances (PFASs). PFASs with longer perfluorinated carbon chain displayed higher uptake rate coefficients (k u ), longer half-life (t 1/2 ) and time to steady-state (t ss ) but lower elimination rate coefficients (k e ) than the shorter ones. Similarly, perfluorosulfonates acids (PFSAs) displayed higher k u , longer t 1/2 and t ss but lower k e than perflurocarboxylic acids (PFCAs) with the same perfluorinated chain length. All the studied PFASs, including those with seven or less perfluorinated carbons, were bioaccumulated in the earthworms and the biota-to-soil accumulation factors (BSAFs) increased with perfluorinated carbon chain length and were greater for PFSAs than for PFCAs of equal perfluoroalkyl chain length. The BSAFs were found to be dependent on the concentrations of PFASs in soil and decreased as the level of PFASs in soil increased. -- Highlights: •PFASs with seven or less perfluoroalkyl carbons were bioaccumulated in earthworm. •The BSAFs of PFASs in earthworm increased with perfluoroalkyl chain length. •The BSAFs of PFSAs were greater than PFCAs of equal perfluoroalkyl chain length. •The k u increased with perfluorinated chain length while k e decreased. •The BSAFs of PFASs decreased as their concentrations in soil increased. -- Perfluoroalkyl substances (PFASs) can be effectively bioaccumulated in earthworms including those with seven or less perfluoroalkyl carbon chain length

Apoptosis of THP-1 derived macrophages induced by sonodynamic therapy using a new sonosensitizer hydroxyl acetylated curcumin.

Directory of Open Access Journals (Sweden)

Longbin Zheng

Full Text Available Curcumin is extracted from the rhizomes of the traditional Chinese herb Curcuma longa. Our previous study indicated curcumin was able to function as a sonosensitizer. Hydroxyl acylated curcumin was synthesized from curcumin to eliminate the unstable hydroxy perssad in our group. The potential use of Hydroxyl acylated curcumin as a sonosensitizer for sonodynamic therapy (SDT requires further exploration. This study investigated the sonodynamic effect of Hydroxyl acylated curcumin on THP-1 macrophage. THP-1 macrophages were cultured with Hydroxyl acylated curcumin at a concentration of 5.0 μg/mL for 4 hours and then exposed to pulse ultrasound irradiation (0.5 W/cm2 with 1.0 MHz for 5 min, 10 min and 15 min. Six hours later, cell viability decreased significantly by CCK-8 assay. After ultrasound irradiation, the ratio of apoptosis and necrosis in SDT group was higher than that in control, Hydroxyl acylated curcumin alone and ultrasound alone. Moreover, the apoptotic rate was higher than necrotic rate with the flow cytometry analysis. Furthermore, Hydroxyl acylated curcumin-SDT induced reactive oxygen species (ROS generation in THP-1 macrophages immediately after the ultrasound treatment while ROS generation was reduced significantly with the scavenger of singlet oxygen Sodium azide (NaN3. Hydroxyl acylated curcumin-SDT led to a conspicuous loss of mitochondrial membrane potential (MMP compared with other groups, while MMP was increased significantly with the scavenger of singlet oxygen Sodium azide (NaN3, ROS inhibitor N-acetyl cysteine (NAC and Mitochondrial Permeability Transition Pore (MPTP inhibitor Cyclosporin A (CsA. The cytochrome C, cleaved-Caspase-9, cleaved-Caspase-3 and cleaved-PARP upregulated after SDT through Western blotting. These findings suggested that Hydroxyl acylated curcumin under low-intensity ultrasound had sonodynamic effect on THP-1 macrophages via generation of intracellular singlet oxygen and mitochondria

Bioaccumulation and toxicity of CuO nanoparticles by a freshwater invertebrate after waterborne and dietborne exposures

Science.gov (United States)

Croteau, Marie-Noele; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

2014-01-01

The incidental ingestion of engineered nanoparticles (NPs) can be an important route of uptake for aquatic organisms. Yet, knowledge of dietary bioavailability and toxicity of NPs is scarce. Here we used isotopically modified copper oxide (65CuO) NPs to characterize the processes governing their bioaccumulation in a freshwater snail after waterborne and dietborne exposures. Lymnaea stagnalis efficiently accumulated 65Cu after aqueous and dietary exposures to 65CuO NPs. Cu assimilation efficiency and feeding rates averaged 83% and 0.61 g g–1 d–1 at low exposure concentrations (–1), and declined by nearly 50% above this concentration. We estimated that 80–90% of the bioaccumulated 65Cu concentration in L. stagnalis originated from the 65CuO NPs, suggesting that dissolution had a negligible influence on Cu uptake from the NPs under our experimental conditions. The physiological loss of 65Cu incorporated into tissues after exposures to 65CuO NPs was rapid over the first days of depuration and not detectable thereafter. As a result, large Cu body concentrations are expected in L. stagnalis after exposure to CuO NPs. To the degree that there is a link between bioaccumulation and toxicity, dietborne exposures to CuO NPs are likely to elicit adverse effects more readily than waterborne exposures.

Reactivity of glycyl-amino acids toward hydroxyl radical in neutral aqueous solutions

International Nuclear Information System (INIS)

Masuda, Takahiro; Iwashita, Naomi; Shinohara, Hiroyuki; Kondo, Masaharu

1978-01-01

Rate constants for reactions of hydroxyl radicals with several glycyl-amino acids were determined by a competition method using p-nitrosodimethylailine as a reference compound. For glycyl-aliphatic amino acids, the enhancement of reactivity was observed as compared with the corresponding free amino acids. The reactivity was explained qualitatively in terms of partial reactivities assigned to each C-H bond of the dipeptides. For glycyl-aromatic amino acids, the rate constants were found to be almost equal to those of the corresponding free amino acids. The reactivity of a protein toward hydroxyl radical was well understood by summation of the rate constants, corrected by steric factors, of amino acid residues located on surface of the protein. The enhanced reactivity of the aliphatic peptides was interpreted in terms of the difference in interaction energy between NH 2 - and NH 3 + -forms of an aliphatic amino acid, which was calculated for the system including glycine and hydroxyl radical according to CNDO/2 method. (auth.)

Electrolytic coloration and spectral properties of hydroxyl-doped potassium bromide single crystals

International Nuclear Information System (INIS)

Qi, Lan; Song, Cuiying; Gu, Hongen

2013-01-01

Hydroxyl-doped potassium bromide single crystals are colored electrolytically at various temperatures and voltages by using a pointed cathode and a flat anode. The characteristic OH − spectral band is observed in absorption spectrum of uncolored single crystal. The characteristic O − , OH − , U, V 2 , O 2− −V a + , M L1 , F and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current–time curve for electrolytic coloration of hydroxyl-doped potassium bromide single crystal and its relationship with electrolytic coloration processes are given. Production and conversion of color centers are explained. - Highlights: ► We expanded the traditional electrolysis method. ► Hydroxyl-doped potassium bromide crystals were colored electrolytically for the first time. ► Useful V, F and F-aggregate color centers were produced in colored crystals. ► V color centers were produced directly and F as well as F-aggregate color centers indirectly.

Modelling the bioaccumulation of persistent organic pollutants in agricultural food chains for regulatory exposure assessment.

Science.gov (United States)

Takaki, Koki; Wade, Andrew J; Collins, Chris D

2017-02-01

New models for estimating bioaccumulation of persistent organic pollutants in the agricultural food chain were developed using recent improvements to plant uptake and cattle transfer models. One model named AgriSim was based on K OW regressions of bioaccumulation in plants and cattle, while the other was a steady-state mechanistic model, AgriCom. The two developed models and European Union System for the Evaluation of Substances (EUSES), as a benchmark, were applied to four reported food chain (soil/air-grass-cow-milk) scenarios to evaluate the performance of each model simulation against the observed data. The four scenarios considered were as follows: (1) polluted soil and air, (2) polluted soil, (3) highly polluted soil surface and polluted subsurface and (4) polluted soil and air at different mountain elevations. AgriCom reproduced observed milk bioaccumulation well for all four scenarios, as did AgriSim for scenarios 1 and 2, but EUSES only did this for scenario 1. The main causes of the deviation for EUSES and AgriSim were the lack of the soil-air-plant pathway and the ambient air-plant pathway, respectively. Based on the results, it is recommended that soil-air-plant and ambient air-plant pathway should be calculated separately and the K OW regression of transfer factor to milk used in EUSES be avoided. AgriCom satisfied the recommendations that led to the low residual errors between the simulated and the observed bioaccumulation in agricultural food chain for the four scenarios considered. It is therefore recommended that this model should be incorporated into regulatory exposure assessment tools. The model uncertainty of the three models should be noted since the simulated concentration in milk from 5th to 95th percentile of the uncertainty analysis often varied over two orders of magnitude. Using a measured value of soil organic carbon content was effective to reduce this uncertainty by one order of magnitude.

Trimeric Hydrogen Bond in Geometrically Frustrated Hydroxyl Cobalt Halogenides

International Nuclear Information System (INIS)

Xiao-Dong, Liu; Masato, Hagihala; Xu-Guang, Zheng; Dong-Dong, Meng; Wan-Jun, Tao; Sen-Lin, Zhang; Qi-Xin, Guo

2011-01-01

The mid-infrared absorption spectra of geometrically frustrated hydroxyl cobalt halogenides Co 2 (OH) 3 Cl and Co 2 (OH) 3 Br are measured by FTIR spectrometers, and the stretching vibrational modes of hydroxyl groups are found to be 3549cm −1 and 3524cm −1 respectively. Through finding their true terminal O-H group stretching vibration frequencies, we obtain 107cm −1 and 99cm −1 red shift caused by the corresponding O-H···Cl and O-H···Br hydrogen bonds. Rarely reported trimeric hydrogen bonds (Co 3 ≡O-H) 3 ···Cl/Br are pointed out to demonstrate the relative weakness of this kind of hydrogen bond which may have a critical effect on the lattice symmetry and magnetic structures. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Biosynthesis of polybrominated aromatic organic compounds by marine bacteria

Science.gov (United States)

Agarwal, Vinayak; El Gamal, Abrahim A.; Yamanaka, Kazuya; Poth, Dennis; Kersten, Roland D.; Schorn, Michelle; Allen, Eric E.; Moore, Bradley S.

2014-01-01

Polybrominated diphenyl ethers (PBDEs) and polybrominated bipyrroles are natural products that bioaccumulate in the marine food chain. PBDEs have attracted widespread attention due to their persistence in the environment and potential toxicity to humans. However, the natural origins of PBDE biosynthesis are not known. Here we report marine bacteria as producers of PBDEs and establish a genetic and molecular foundation for their production that unifies paradigms for the elaboration of bromophenols and bromopyrroles abundant in marine biota. We provide biochemical evidence of marine brominase enzymes revealing decarboxylative-halogenation enzymology previously unknown among halogenating enzymes. Biosynthetic motifs discovered in our study were used to mine sequence databases to discover unrealized marine bacterial producers of organobromine compounds. PMID:24974229

Literature review on the use of bioaccumulation for heavy metal removal and recovery

International Nuclear Information System (INIS)

Benemann, J.R.; Wilde, E.W.

1991-02-01

Bioaccumulation of metals by microbes -- '' bioremoval'' -- is a powerful new technology for the concentration, recovery, and removal of toxic heavy metals and radionuclides from waste streams and contaminated environments. Algae are particularly well suited for metal bioremoval. A recent commercial application of bioremoval utilizes inert (dead) immobilized microalgae biomass as ion exchange materials for the removal of heavy metals from industrial waste waters. Also, living microalgal cultures have been used to remove metals from mine effluents. Microbial cells and biomass can bioaccumulate metals and radionuclides by a large variety of mechanisms, both dependent and independent of cell metabolism. Microbial cell walls can act as ion exchange and metal complexation agents. Heavy metals can precipitate and even crystallize on cell surfaces. Metabolically produced hydrogen sulfide or other metabolic products can bioprecipitate heavy metals. Many microbes produce both intra- and extracellular metal complexing agents which could be considered in practical metal removal processes. Bioremoval processes are greatly affected by the microbial species and even strain used, pH, redox potential, temperature, and other conditions under which the microbes are grown. Development of practical applications of bioremoval requires applies research using the particular waste solutions to be treated, or close simulations thereof. From a practical perspective, the selection of the microbial biomass and the process for contacting the microbial biomass with the metal containing solutions are the key issues. Much of the recent commercial R ampersand D has emphasized commercially available, inert, microbial biomass sources as these can be acquired in sufficient quantities at affordable costs. The fundamental research and practical applications of bioaccumulation by microalgae suggests these organisms warrant a high priority in the development of advanced bioremoval processes

Literature review on the use of bioaccumulation for heavy metal removal and recovery

Energy Technology Data Exchange (ETDEWEB)

Benemann, J.R. (Benemann (J.R.), Pinole, CA (United States)); Wilde, E.W. (Westinghouse Savannah River Co., Aiken, SC (United States))

1991-02-01

Bioaccumulation of metals by microbes -- bioremoval'' -- is a powerful new technology for the concentration, recovery, and removal of toxic heavy metals and radionuclides from waste streams and contaminated environments. Algae are particularly well suited for metal bioremoval. A recent commercial application of bioremoval utilizes inert (dead) immobilized microalgae biomass as ion exchange materials for the removal of heavy metals from industrial waste waters. Also, living microalgal cultures have been used to remove metals from mine effluents. Microbial cells and biomass can bioaccumulate metals and radionuclides by a large variety of mechanisms, both dependent and independent of cell metabolism. Microbial cell walls can act as ion exchange and metal complexation agents. Heavy metals can precipitate and even crystallize on cell surfaces. Metabolically produced hydrogen sulfide or other metabolic products can bioprecipitate heavy metals. Many microbes produce both intra- and extracellular metal complexing agents which could be considered in practical metal removal processes. Bioremoval processes are greatly affected by the microbial species and even strain used, pH, redox potential, temperature, and other conditions under which the microbes are grown. Development of practical applications of bioremoval requires applies research using the particular waste solutions to be treated, or close simulations thereof. From a practical perspective, the selection of the microbial biomass and the process for contacting the microbial biomass with the metal containing solutions are the key issues. Much of the recent commercial R D has emphasized commercially available, inert, microbial biomass sources as these can be acquired in sufficient quantities at affordable costs. The fundamental research and practical applications of bioaccumulation by microalgae suggests these organisms warrant a high priority in the development of advanced bioremoval processes.

Predicting the bioaccumulation of polyaromatic hydrocarbons and polychlorinated biphenyls in benthic animals in sediments

Energy Technology Data Exchange (ETDEWEB)

Tuikka, A.I., E-mail: anitat@student.uef.fi [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 111, FI-80101 Joensuu (Finland); Leppänen, M.T., E-mail: Matti.T.Leppanen@ymparisto.fi [Finnish Environment Institute, Laboratories/Research and Innovation Laboratory, P.O. Box 35, University of Jyväskylä, FI-40014 Jyväskylä (Finland); Akkanen, J., E-mail: jarkko.akkanen@uef.fi [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 111, FI-80101 Joensuu (Finland); Sormunen, A.J., E-mail: Arto.Sormunen@mamk.fi [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 111, FI-80101 Joensuu (Finland); Leonards, P.E.G., E-mail: pim.leonards@vu.nl [Institute for Environmental Studies, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Hattum, B. van, E-mail: bert.vanhattum@deltares.nl [Institute for Environmental Studies, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands); Vliet, L.A. van, E-mail: lavanvliet@hotmail.com [Ministry of Transport, Public Works and Water Management, National Institute for Coastal and Marine Management/RIKZ, P.O. Box 207, 9750 AE Haren (Netherlands); Brack, W., E-mail: werner.brack@ufz.de [Helmholtz Centre for Environmental Research - UFZ, Department of Effect-Directed Analysis, Permoserstraße 15, 04318 Leipzig (Germany); Smedes, F., E-mail: smedes@recetox.muni.cz [Ministry of Transport, Public Works and Water Management, National Institute for Coastal and Marine Management/RIKZ, P.O. Box 207, 9750 AE Haren (Netherlands); and others

2016-09-01

There were two main objectives in this study. The first was to compare the accuracy of different prediction methods for the chemical concentrations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the organism, based on the measured chemical concentrations existing in sediment dry matter or pore water. The predicted tissue concentrations were compared to the measured ones after 28-day laboratory test using oligochaeta worms (Lumbriculus variegatus). The second objective was to compare the bioaccumulation of PAHs and PCBs in the laboratory test with the in situ bioaccumulation of these compounds. Using the traditional organic carbon-water partitioning model, tissue concentrations were greatly overestimated, based on the concentrations in the sediment dry matter. Use of an additional correction factor for black carbon with a two-carbon model, significantly improved the bioaccumulation predictions, thus confirming that black carbon was important in binding the chemicals and reducing their accumulation. The predicted PAH tissue concentrations were, however, high compared to the observed values. The chemical concentrations were most accurately predicted from their freely dissolved pore water concentrations, determined using equilibrium passive sampling. The patterns of PCB and PAH accumulation in sediments for laboratory-exposed L. variegatus were similar to those in field-collected Lumbriculidae worms. Field-collected benthic invertebrates and L. variegatus accumulated less PAHs than PCBs with similar lipophilicity. The biota to sediment accumulation factors of PAHs tended to decrease with increasing sediment organic carbon normalized concentrations. The presented data yields bioconcentration factors (BCF) describing the chemical water-lipid partition, which were found to be higher than the octanol-water partition coefficients, but on a similar level with BCFs drawn from relevant literature. In conclusion, using the two-carbon model method

Iron-functionalized Al-SBA-15 for benzene hydroxylation

NARCIS (Netherlands)

Li, Y.; Xia, H.; Fan, F.; Feng, Z.; Santen, van R.A.; Hensen, E.J.M.; Li, Can

2008-01-01

For the first time an ordered mesoporous silica (Fe–Al-SBA-15) with catalytically active isolated Fe surface species for the hydroxylation of benzene with nitrous oxide is prepared by introduction of Fe3+ in the synthesis gel of Al-SBA-15. Graphical abstract image for this article (ID: b717079c)

Modeling {sup 137}Cs bioaccumulation in the salmon–resident killer whale food web of the Northeastern Pacific following the Fukushima Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Alava, Juan José, E-mail: jalavasa@sfu.ca; Gobas, Frank A.P.C.

2016-02-15

To track the long term bioaccumulation of {sup 137}Cs in marine organisms off the Pacific Northwest coast of Canada, we developed a time dependent bioaccumulation model for {sup 137}Cs in a marine mammalian food web that included fish-eating resident killer whales. The model outcomes show that {sup 137}Cs can be expected to gradually bioaccumulate in the food web over time as demonstrated by the increase of the apparent trophic magnification factor of {sup 137}Cs, ranging from 0.76 after 1 month of exposure to 2.0 following 30 years of exposure. {sup 137}Cs bioaccumulation is driven by relatively rapid dietary uptake rates, moderate depuration rates in lower trophic level organisms and slow elimination rates in high trophic level organisms. Model estimates of the {sup 137}Cs activity in species of the food web, based on current measurements and forecasts of {sup 137}Cs activities in oceanic waters and sediments off the Canadian Pacific Northwest, indicate that the long term {sup 137}Cs activities in fish species including Pacific herring, wild Pacific salmon, sablefish and halibut will remain well below the current {sup 137}Cs-Canada Action Level for consumption (1000 Bq/kg) following a nuclear emergency. Killer whales and Pacific salmon are expected to exhibit the largest long term {sup 137}Cs activities and may be good sentinels for monitoring {sup 137}Cs in the region. Assessment of the long term consequences of {sup 137}Cs releases from the Fukushima aftermath should consider the extent of ecological magnification in addition to ocean dilution. - Highlights: • A food web bioaccumulation model to assess the biomagnification of {sup 137}Cs is developed. • Cesium 137 exhibits bioaccumulation over time as simulated by the model. • Predicted activities in marine biota are below {sup 137}Cs-food consumption benchmarks. • Long-term monitoring of {sup 137}Cs in the ocean will improve the model predictions.

Removal of some radionuclides from water by bioaccumulation

International Nuclear Information System (INIS)

Miskovic, D.; Conkic, L.; Dalmacija, B.; Gantar, M.

1992-01-01

First objective of this study was to investigate the application of biologically activated carbon (BAC) as well as its comparison to adsorption, with the aim of removing some radionuclides from water. The isotopes Cs 134 and Cs 137 were bioaccumulated by BAC up to 50%, while the I 131 isotope was only physicochemically adsorbed (about 40%). Also, the process of radionuclides (Cs 137 , Ce 139 , Co 57 , Co 60 ) fixation on blue-green algae (Nostoc sp.) was investigated. The kinetics of the removal of these radionuclides from water was recorded. It was found that after a contact period of about half an hour 40-70% of the activity was removed. (Author)

Bioaccumulation of heavy metals in organs of fresh water fish Cyprinus carpio (Common carp)

International Nuclear Information System (INIS)

Vinodhini, R.; Narayanan, M.

2008-01-01

The objective of the present study is to determine the bioaccumulation of heavy metals in various organs of the fresh water fish exposed to heavy metal contaminated water system. The experimental fish was exposed to Cr. Ni, Cd and Pb at sublethal concentrations for periods of 32 days. The elements Cd, Pb, Ni and Cr were assayed using Shimadzu AA 6200 atomic absorption spectrophotometry and the results were given as μg/g dry wt. The accumulation of heavy metal gradually increases in liver during the heavy metal exposure period. All the results were statistically significant at p Pb > Ni > Cr and Pb > Cd > Ni > Cr. Similarly, in case of kidney and flesh tissues, the order was Pb > Cd > Cr > Ni and Pb > Cr > Cd > Ni. In all heavy metals, the bioaccumulation of lead and cadmium proportion was significantly increased in the tissues of Cyprinus carpio (Common carp)

The Influence of Hydroxylated Carbon Nanotubes on Epoxy Resin Composites

Directory of Open Access Journals (Sweden)

Jiaoxia Zhang

2012-01-01

Full Text Available Hydroxylated multiwall carbon nanotubes (MWNTs/epoxy resin nanocomposites were prepared with ultrasonic dispersion and casting molding. The effect of hydroxylated MWNTs content on reactive activity of composites is discussed. Then the flexural and electrical properties were studied. Transmission electron microscope was employed to characterize the microstructure of nanocomposites. As a result, the reactive activity of nanocomposites obtained increases with the increasing content of MWNTs. When MWNTs content of the composites is 1 wt%, as compared to neat resin, the flexural strength increases from 143 Mpa to 156 MPa, the modulus increases from 3563 Mpa to 3691 MPa, and the volume and surface resistance of nanocomposites decrease by two orders of magnitude, respectively.

Steroid Hydroxylation by Basidiomycete Peroxygenases: a Combined Experimental and Computational Study

Science.gov (United States)

Babot, Esteban D.; del Río, José C.; Cañellas, Marina; Sancho, Ferran; Lucas, Fátima; Guallar, Víctor; Kalum, Lisbeth; Lund, Henrik; Gröbe, Glenn; Scheibner, Katrin; Ullrich, René; Hofrichter, Martin; Martínez, Angel T.

2015-01-01

The goal of this study is the selective oxyfunctionalization of steroids under mild and environmentally friendly conditions using fungal enzymes. With this purpose, peroxygenases from three basidiomycete species were tested for the hydroxylation of a variety of steroidal compounds, using H2O2 as the only cosubstrate. Two of them are wild-type enzymes from Agrocybe aegerita and Marasmius rotula, and the third one is a recombinant enzyme from Coprinopsis cinerea. The enzymatic reactions on free and esterified sterols, steroid hydrocarbons, and ketones were monitored by gas chromatography, and the products were identified by mass spectrometry. Hydroxylation at the side chain over the steroidal rings was preferred, with the 25-hydroxyderivatives predominating. Interestingly, antiviral and other biological activities of 25-hydroxycholesterol have been reported recently (M. Blanc et al., Immunity 38:106–118, 2013, http://dx.doi.org/10.1016/j.immuni.2012.11.004). However, hydroxylation in the ring moiety and terminal hydroxylation at the side chain also was observed in some steroids, the former favored by the absence of oxygenated groups at C-3 and by the presence of conjugated double bonds in the rings. To understand the yield and selectivity differences between the different steroids, a computational study was performed using Protein Energy Landscape Exploration (PELE) software for dynamic ligand diffusion. These simulations showed that the active-site geometry and hydrophobicity favors the entrance of the steroid side chain, while the entrance of the ring is energetically penalized. Also, a direct correlation between the conversion rate and the side chain entrance ratio could be established that explains the various reaction yields observed. PMID:25862224

Bioaccumulation of sodium alkyl sulfate zinc chloride and their mixture in young goby proterorhinus marmoratus pall

Energy Technology Data Exchange (ETDEWEB)

Topcuoglu, S.; Birol, E. (Cekmece Nuclear Research and Training Center, Istanbul (Turkey))

1982-12-01

The bioaccumulation of labelled surfactant, 35S-labelled sodium lauryl sulfate and 65Zn-labelled zinc chloride, was investigated both as a mixture and alone by themselves in young goby. The concentration factor of 7.15 was calculated for the surfactant in the whole-body fish and there was no effect of zinc chloride on this bioaccumulation process. Biological half-life of the surfactant was around 35 hours. The effects of surfactants on the zinc accumulation were also followed under the same conditions. The results indicated that the sodium lauryl sulfate had no effect on the accumulation of zinc, however, the other surfactant, linear alkylbenzene sulfonate, caused a significant increase in the zinc accumulation in comparison with the control group, during the uptake period.

Bioaccumulation of sodium alkyl sulfate zinc chloride and their mixture in young goby proterorhinus marmoratus pall

International Nuclear Information System (INIS)

Topcuoglu, S.; Birol, E.

1982-01-01

The bioaccumulation of labelled surfactant, 35S-labelled sodium lauryl sulfate and 65Zn-labelled zinc chloride, was investigated both as a mixture and alone by themselves in young goby. The concentration factor of 7.15 was calculated for the surfactant in the whole-body fish and there was no effect of zinc chloride on this bioaccumulation process. Biological half-life of the surfactant was around 35 hours. The effects of surfactants on the zinc accumulation were also followed under the same conditions. The results indicated that the sodium lauryl sulfate had no effect on the accumulation of zinc, however, the other surfactant, linear alkylbenzene sulfonate, caused a significant increase in the zinc accumulation in comparison with the control group, during the uptake period. (author)

Use of 65 Zn as radioactive tracer in the bioaccumulation study of zinc by aquatic organisms

International Nuclear Information System (INIS)

Malagrino, W.

1992-01-01

The present work has as main objective to emphasize the importance of using radioactive tracers as well as to establish a methodology for the utilization of 65 Zn in the bioaccumulation study of zinc by Poecilia reticulata. The exposure time varied from 5 days (short term experiments) to 30 days (long term experiments). The bioaccumulation of zinc from the water as well as the elimination of the metal previously absorbed were determined by measuring the activity of 65 Zn which was added to the water in the beginning of the experiments. The technique chosen is suitable to study the behaviour of the stable zinc since the radionuclide used is an isotope of the same element and therefore presents the same chemical properties. (author)

Formation of Hydroxylamine from Ammonia and Hydroxyl Radicals

Science.gov (United States)

Krim, Lahouari; Zins, Emilie-Laure

2014-06-01

In the interstellar medium, as well as in icy comets, ammonia may be a crucial species in the first step toward the formation of amino-acids and other prebiotic molecules such as hydroxylamine (NH2OH). It is worth to notice that the NH3/H2 ratio in the ISM is 3 10-5 compared the H2O/H2 one which is only 7 10-5. Using either electron-UV irradiations of water-ammonia ices or successive hydrogenation of solid nitric oxide, laboratory experiments have already shown the feasibility of reactions that may take place on the surface of ice grains in molecular clouds, and may lead to the formation of this precursor. Herein is proposed a new reaction pathway involving ammonia and hydroxyl radicals generated in a microwave discharge. Experimental studies, at 3 and 10 K, in solid phase as well as in neon matrix have shown that this reaction proceed via a hydrogen abstraction, leading to the formation of NH2 radical, that further recombine with hydroxyl radical to form hydroxylamine, under non-energetic conditions.

Thyroid hormone-like and estrogenic activity of hydroxylated PCBs in cell culture

International Nuclear Information System (INIS)

Kitamura, Shigeyuki; Jinno, Norimasa; Suzuki, Tomoharu; Sugihara, Kazumi; Ohta, Shigeru; Kuroki, Hiroaki; Fujimoto, Nariaki

2005-01-01

The thyroid hormone-disrupting activity of hydroxylated PCBs was examined. 4-Hydroxy-2,2',3,4',5,5'-hexachlorobiphenyl (4-OH-2,2',3,4',5,5'-HxCB), 4-hydroxy-3,3',4',5-tetrachlorobiphenyl (4-OH-3,3',4',5-TCB) and 4,4'-dihydroxy-3,3',5,5'-tetrachlorobiphenyl (4,4'-diOH-3,3',5,5'-TCB), which have been detected as metabolites of PCBs in animals and humans, and six other 4-hydroxylated PCBs markedly inhibited the binding of triiodothyronine (1 x 10 -10 M) to thyroid hormone receptor (TR) in the concentration range of 1 x 10 -6 to 1 x 10 -4 M. However, 4-hydroxy-2',4',6'-trichlorobiphenyl (4-OH-2',4',6'-TCB), 3-hydroxy-2,2',5,5'-tetrachlorobiphenyl, 4-hydroxy-2,2',5,5'-tetrachlorobiphenyl, 4-hydroxy-2,3,3',4'-tetrachlorobiphenyl, 2,3',5,5'-tetrachlorobiphenyl and 2,3',4',5,5'-pentachlorodiphenyl did not show affinity for TR. The thyroid hormonal activity of PCBs was also examined using rat pituitary cell line GH3 cells, which grow and release growth hormone in a thyroid hormone-dependent manner. 4-OH-2,2',3,4',5,5'-HxCB, 4,4'-diOH-3,3',5,5'-TCB and 4-OH-3,3',4',5-TCB enhanced the proliferation of GH3 cells and stimulated their production of growth hormone in the concentration range of 1 x 10 -7 to 1 x 10 -4 M, while PCBs which had no affinity for thyroid hormone receptor were inactive. In contrast, only 4-OH-2',4',6'-TCB exhibited a significant estrogenic activity using estrogen-responsive reporter assay in MCF-7 cells. However, the 3,5-dichloro substitution of 4-hydroxylated PCBs markedly decreased the estrogenic activity. These results suggest that, at least for the 17 PCB congeners and hydroxylated metabolites tested, a 4-hydroxyl group in PCBs is essential for thyroid hormonal and estrogenic activities, and that 3,5-dichloro substitution favors thyroid hormonal activity, but not estrogenic activity

New fluorescent probes of the hydroxyl radical: characterisation and modelization of the reactivity of coumarin derivatives with HO

International Nuclear Information System (INIS)

Louit, G.

2005-10-01

The hydroxyl radical is involved in a wide range of different fields, from oxidative stress to atmospheric chemistry. In addition to the study of oxidative damage in biological media, the hydroxyl radical detection allows to perform a dosimetry when it is produced by ionising radiation. The aims of this work have been double: - to improve the detection of the hydroxyl radical by the design of new probes - to improve knowledge on the reactive pathways in which the hydroxyl radical is involved. We have studied the coumarin molecule, as well as 6 derivatives that we have synthesised, as fluorescent probes of the hydroxyl radical. Firstly, fluorescence spectroscopy and HPLC chromatography have allowed the evaluation of the sensibility and selectivity of detection of the probes. Consequently to this study, two applications have been developed, concerning the determination of rate constants by competition kinetics and bidimensional dosimetry. Secondly, we have studied the reactivity of the hydroxyl radical through the regioselectivity of its addition on the aromatic cycle. This problem was addressed by the combined use of experimental methods such as time resolved kinetics and HPLC along with interpretation from classical and ab initio modelization. (author)

Structure, electronic properties, and aggregation behavior of hydroxylated carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

López-Oyama, A. B.; Silva-Molina, R. A.; Ruíz-García, J.; Guirado-López, R. A., E-mail: guirado@ifisica.uaslp.mx [Instituto de Física “Manuel Sandoval Vallarta,” Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí (Mexico); Gámez-Corrales, R. [Departamento de Física, Universidad de Sonora, Apartado Postal 5-088, 83190, Hermosillo, Sonora (Mexico)

2014-11-07

We present a combined experimental and theoretical study to analyze the structure, electronic properties, and aggregation behavior of hydroxylated multiwalled carbon nanotubes (OH–MWCNT). Our MWCNTs have average diameters of ∼2 nm, lengths of approximately 100–300 nm, and a hydroxyl surface coverage θ∼0.1. When deposited on the air/water interface the OH–MWCNTs are partially soluble and the floating units interact and link with each other forming extended foam-like carbon networks. Surface pressure-area isotherms of the nanotube films are performed using the Langmuir balance method at different equilibration times. The films are transferred into a mica substrate and atomic force microscopy images show that the foam like structure is preserved and reveals fine details of their microstructure. Density functional theory calculations performed on model hydroxylated carbon nanotubes show that low energy atomic configurations are found when the OH groups form molecular islands on the nanotube's surface. This patchy behavior for the OH species is expected to produce nanotubes having reduced wettabilities, in line with experimental observations. OH doping yields nanotubes having small HOMO–LUMO energy gaps and generates a nanotube → OH direction for the charge transfer leading to the existence of more hole carriers in the structures. Our synthesized OH–MWCNTs might have promising applications.

Synthesis and properties evaluation of sulfobetaine surfactant with double hydroxyl

Science.gov (United States)

Zhou, Ming; Luo, Gang; Zhang, Ze; Li, Sisi; Wang, Chengwen

2017-09-01

A series of sulfobetaine surfactants {N-[(3-alkoxy-2-hydroxyl)propoxy] ethyl-N,N-dimethyl-N-(2-hydroxyl)propyl sulfonate} ammonium chloride were synthesized with raw materials containing linear saturated alcohol, N,N-dimethylethanolamine, sodium 3-chloro-2-hydroxyl propane sulfonic acid and epichlorohydrin. The molecule structures of sulfobetaine surfactants were characterized by FTIR, 1HNMR and elemental analysis. Surface tension measurements can provide us information about the surface tension at the CMC (γCMC), pC20, Γmax and Amin. The pC20 values of sulfobetaine surfactants increase with the hydrophobic chain length increasing. Amin values of the surfactants decrease with increasing hydrophobic chain length from 10 to 14. The critical micelle concentration (CMC) and surface tension (γCMC) values of the sulfobetaine surfactants decrease with increasing hydrophobic chain length from 10 to 16. The lipophilicity of surfactant was enhanced with the increase of the carbon chain, however, the ability of anti-hard water was weakened. The minimum oil/water interfacial tension of four kinds of sulfobetaine surfactants is 10-2-10-3 mN/m magnitude, which indicates that the synthesized bis-hydroxy sulfobetaine surfactants have a great ability to reduce interfacial tension in the surfactant flooding system. The surface tension (γCMC) values of synthesized surfactants were lower compared with conventional anionic surfactant sodium dodecyl sulfonate.

Lead (Pb) bioaccumulation; genera Bacillus isolate S1 and SS19 as a case study

Science.gov (United States)

Arifiyanto, Achmad; Apriyanti, Fitria Dwi; Purwaningsih, Puput; Kalqutny, Septian Hary; Agustina, Dyah; Surtiningsih, Tini; Shovitri, Maya; Zulaika, Enny

2017-06-01

Lead (Pb) includes a group of large heavy metal in nature was toxic either on animal or human and did not provide an advantage function biologically. Bacillus isolates S1 and SS19 known resistant to lead up to 50 mg / L PbCl2. In this research will be examined whether genera Bacillus isolates S1 and SS19 could accumulate metal lead (Pb), their capability in accumulating and profile protein differences when the bacteria genera Bacillus isolates S1 and SS19 get exposed metal lead (Pb). Inoculum at age ± 9 hours are used, with a Nutrient Broth (NB) containing 50, 75 and 100 mg / L PbCl2. Inductively Coupled Plasma Atomic Emission Spectrometry (ICP) used to assessed Pb2+ concentrations. Bioaccumulation levels of Pb2+ by Bacillus isolate S1 and SS19 related to the distinction of beginning concentration to the final concentration. Bacillus isolate S1 achieved 53% and 51% bioaccumulation efficiency rate in lead presence concentration (75 and 100 mg/L) and 51% (50 mg/L). Another way Bacillus isolate SS19 was able to accumulate 57% (50 mg/L PbCl2) and kept stable on 36% bioaccumulation efficiency rate (75 and 100 mg/L PbCl2). Regarding SDS-PAGE electrophoresis protein profile result, protein in ± 127 kDa, molecule mass detected in the presence of Lead for Bacillus isolate S1.

Bioaccumulation of glyphosate and its formulation Roundup Ultra in Lumbriculus variegatus and its effects on biotransformation and antioxidant enzymes

Energy Technology Data Exchange (ETDEWEB)

Contardo-Jara, Valeska [Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Inland Fisheries, Biochemical Regulation, Mueggelseedamm 301, 12587 Berlin (Germany)], E-mail: contardo@igb-berlin.de; Klingelmann, Eva [Technische Universitaet Berlin/Berlin Institute of Technology, Department of Ecology, Chair of Soil Protection, Salzufer 12, 10587 Berlin (Germany)], E-mail: eva.klingelmann@TU-Berlin.de; Wiegand, Claudia [Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Inland Fisheries, Biochemical Regulation, Mueggelseedamm 301, 12587 Berlin (Germany); Humboldt University Berlin, Faculty of Biology, Unter den Linden 6, 10099 Berlin (Germany)], E-mail: cwiegand@igb-berlin.de

2009-01-15

The bioaccumulation potential of glyphosate and the formulation Roundup Ultra, as well as possible effects on biotransformation and antioxidant enzymes in Lumbriculus variegatus were compared by four days exposure to concentrations between 0.05 and 5 mg L{sup -1} pure glyphosate and its formulation. Bioaccumulation was determined using {sup 14}C labeled glyphosate. The bioaccumulation factor (BCF) varied between 1.4 and 5.9 for the different concentrations, and was higher than estimated from log P{sub ow}. Glyphosate and its surfactant POEA caused elevation of biotransformation enzyme soluble glutathione S-transferase at non-toxic concentrations. Membrane bound glutathione S-transferase activity was significantly elevated in Roundup Ultra exposed worms, compared to treatment with equal glyphosate concentrations, but did not significantly differ from the control. Antioxidant enzyme superoxide dismutase was significantly increased by glyphosate but in particular by Roundup Ultra exposure indicating oxidative stress. The results show that the formulation Roundup Ultra is of more ecotoxicological relevance than the glyphosate itself. - Roundup Ultra is of more ecotoxicological relevance than the active ingredient, glyphosate, to Lumbriculus variegatus regarding accumulation potential and enzymatic responses.

Bioaccumulation of glyphosate and its formulation Roundup Ultra in Lumbriculus variegatus and its effects on biotransformation and antioxidant enzymes

International Nuclear Information System (INIS)

Contardo-Jara, Valeska; Klingelmann, Eva; Wiegand, Claudia

2009-01-01

The bioaccumulation potential of glyphosate and the formulation Roundup Ultra, as well as possible effects on biotransformation and antioxidant enzymes in Lumbriculus variegatus were compared by four days exposure to concentrations between 0.05 and 5 mg L -1 pure glyphosate and its formulation. Bioaccumulation was determined using 14 C labeled glyphosate. The bioaccumulation factor (BCF) varied between 1.4 and 5.9 for the different concentrations, and was higher than estimated from log P ow . Glyphosate and its surfactant POEA caused elevation of biotransformation enzyme soluble glutathione S-transferase at non-toxic concentrations. Membrane bound glutathione S-transferase activity was significantly elevated in Roundup Ultra exposed worms, compared to treatment with equal glyphosate concentrations, but did not significantly differ from the control. Antioxidant enzyme superoxide dismutase was significantly increased by glyphosate but in particular by Roundup Ultra exposure indicating oxidative stress. The results show that the formulation Roundup Ultra is of more ecotoxicological relevance than the glyphosate itself. - Roundup Ultra is of more ecotoxicological relevance than the active ingredient, glyphosate, to Lumbriculus variegatus regarding accumulation potential and enzymatic responses

Role of hydroxylation modification on the structure and property of reduced graphene oxide/TiO{sub 2} hybrids

Energy Technology Data Exchange (ETDEWEB)

Cao, Shiyi [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Liu, Tiangui, E-mail: tianguiliu@gmail.com [College of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Tsang, Yuenhong [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, 999077 (China); Chen, Chuansheng, E-mail: 1666423158@qq.com [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China)

2016-09-30

Graphical abstract: The structure model and enhancement mechanism of hydroxylation treatment on adsorbability and photocatalytic activity. - Highlights: • Highly-hydroxylated TiO{sub 2}/rGO hybrids can be obtained by UV pre-excitation and microwave method. • Surface hydroxylation induces many defects (Ti{sup 3+}, O vacancy and Ti-OH) and changes color into yellow. • Hydroxylation expands the light absorption up to about 600 nm and benefits to adsorb organic dyes. • ESR reveals the self-accumulation of hydroxyl radicals under the irradiation of UV and visible light. • The photoinduced defects and rGO/TiO{sub 2}@OH-TiO{sub 2} heterojunctions enable the excellent applicability. - Abstract: To extend the spectra response of TiO{sub 2} and enhance its photocatalytic activity, surface modification and catalyst supporter have attracted great attention. In this report, a simple and versatile approach has been developed to hydroxylate the reduced graphene oxide/TiO{sub 2} hybrids (OH-rGO/TiO{sub 2}) by UV-microwave method, and the enhanced mechanisms of hydroxylation were analyzed in details. Experimental results show that TiO{sub 2} nanocrystals@OH-TiO{sub 2} heterojunctions formed on rGO sheets in situ by UV/H{sub 2}O{sub 2} process. Hydroxylation not only can induce many surface defects (Ti{sup 3+}, O vacancy and Ti-OH) on the surface of TiO{sub 2}, but also change the color into yellow and strengthen the interaction between rGO and TiO{sub 2}. OH-rGO/TiO{sub 2} hybrids showed excellent durability for high-concentration dyes, and exhibited strong adsorbability and photocatalytic activity. These enhancements are attributed to the excellent property of rGO and surface defects of TiO{sub 2} induced by hydroxylation, which expand the light absorption up to 600 nm, benefit to the self-dispersion of hybrids, and improve the adsorption dynamic and charge transfer with lower carrier’s recombination.

Biochars induced modification of dissolved organic matter (DOM) in soil and its impact on mobility and bioaccumulation of arsenic and cadmium.

Science.gov (United States)

Li, Gang; Khan, Sardar; Ibrahim, Muhammad; Sun, Tian-Ran; Tang, Jian-Feng; Cotner, James B; Xu, Yao-Yang

2018-04-15

Biochar application has attracted great attention due to its diverse uses and benefits in the fields of environmental management and agriculture. Biochar modifies the composition of dissolved organic matter (DOM) in soil, which directly or indirectly controls the mobility of metal contaminants and their bioaccumulation. In this study, ten different hydrothermal biochars pyrolysed from mushroom waste (MSBC), soybean straw (SBBC), sewage sludge (SSBC), peanut shells (PNBC) and rice straw (RSBC) at two pyrolysis temperatures (200 °C and 350 °C) were used to investigate DOM changes in soil solution and their effects on metal availability and bioaccumulation. Biochar induced modification of soil DOM which was characterized by spectroscopic analysis of water soluble organic carbon, specific absorbance (SUVA 254 ), UV-vis absorption, spectral slope (S R ) and the absorption coefficient. Regarding rice plant growth, the biochar effects on biomass were greatly varied. Biochars (except for RSBC and MSBC) prepared at high temperature significantly (P ≤ 0.05) suppressed the availability of As and Cd in soil and their subsequent bioaccumulation in rice plants. The highest reduction (88%) in bioaccumulated As was observed in rice grown on soil amended with SBBC prepared at 350 °C (the highest temperature for hydrothermal technique). The addition of biochars (except RSBC and MSBC) prepared at high temperature markedly (p < 0.05) decreased AsIII (30-92%), while the effects on dimethylarsenic acid (DMA) and arsenate (AsV) concentrations were not significant except for SSBC350 (prepared at 350 °C) treatment. These results highlight the potential of biochar-DOM interactions as an important mechanism for suppressing the mobility and bioaccumulation of As and Cd in biochar-amended paddy agricultural systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Formation of hydroxyl radicals in the human lens is related to the severity of nuclear cataract

DEFF Research Database (Denmark)

Garner, B; Davies, Michael Jonathan; Truscott, R J

2000-01-01

Recent studies have identified specific hydroxylated amino acid oxidation products which strongly suggest the presence of hydroxyl radical (HO.)-damaged proteins in human cataractous lenses. In the present study, the ability of early stage (type II) and advanced (type IV) nuclear cataractous lens...

Effects of nanoplastics and microplastics on toxicity, bioaccumulation, and environmental fate of phenanthrene in fresh water.

Science.gov (United States)

Ma, Yini; Huang, Anna; Cao, Siqi; Sun, Feifei; Wang, Lianhong; Guo, Hongyan; Ji, Rong

2016-12-01

Contamination of fine plastic particles (FPs), including micrometer to millimeter plastics (MPs) and nanometer plastics (NPs), in the environment has caught great concerns. FPs are strong adsorbents for hydrophobic toxic pollutants and may affect their fate and toxicity in the environment; however, such information is still rare. We studied joint toxicity of FPs with phenanthrene to Daphnia magna and effects of FPs on the environmental fate and bioaccumulation of 14 C-phenanthrene in fresh water. Within the five sizes particles we tested (from 50 nm to 10 μm), 50-nm NPs showed significant toxicity and physical damage to D. magna. The joint toxicity of 50-nm NPs and phenanthrene to D. magna showed an additive effect. During a 14-days incubation, the presence of NPs significantly enhanced bioaccumulation of phenanthrene-derived residues in daphnid body and inhibited the dissipation and transformation of phenanthrene in the medium, while 10-μm MPs did not show significant effects on the bioaccumulation, dissipation, and transformation of phenanthrene. The differences may be attributed to higher adsorption of phenanthrene on 50-nm NPs than 10-μm MPs. Our findings underlined the high potential ecological risks of FPs, and suggested that NPs should be given more concerns, in terms of their interaction with hydrophobic pollutants in the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioaccumulation of selenium and induced biological effects in the filter feeding bivalve Corbicula fluminea: influence of ventilatory activity, selenium speciation and route of transfer; Bioaccumulation du selenium et effets biologiques induits chez le bivalve filtreur Corbicula fluminea: prise en compte de l'activite ventilatoire, de la speciation du selenium et de la voie de contamination

Energy Technology Data Exchange (ETDEWEB)

Fournier, E

2005-10-15

Selenium is an essential micro-nutrient for most of living organisms. However, toxic effects in several ecosystems have been reported in the literature. Toxicity comprehension is difficult due to the complexity of Se oxidation states in the environment. The aim of this thesis work was to acquire knowledge on the physiological and environmental factors involved in bioaccumulation and toxicity processes in the freshwater filter-feeding bivalve C. fluminea. The aims were: i) to define what the factors involved in Se bioaccumulation processes in the bivalve are, ii) to characterize Se bioaccumulation at different biological organisation levels, iii) to investigate Se toxic effects. First experiments, carried out for short term exposure duration (3 days), have permitted to underline the importance of Se chemical speciation in bioaccumulation processes in C. fluminea. It has been shown that the organic form, seleno-methionine, was much more bio-available than the inorganic forms, selenite and selenate. Moreover, the route of transfer was determinant in those processes. Inorganic forms have been better extracted by trophic route, whereas seleno-methionine has been better extracted by the direct route. In our experimental conditions, ventilation of the bivalve has not been a limiting factor for Se bioaccumulation by the direct route, whereas it has been for bioaccumulation by the trophic route. Ventilation has been largely modified by the presence of dissolved selenite and seleno-methionine. We have shown that the kinetics of seleno-methionine bioaccumulation are much more fast than those of selenite. Moreover, when introduced as SeMet, internalized Se appeared to be relatively remanent in soft tissues of C. fluminea in comparison with Se internalized when introduced as selenite. Subcellular and molecular distributions of these forms were very different. Finally, it has been shown that seleno-methionine and selenite could generate weak alterations of the anti

Synthesis and gas transport properties of hydroxyl-functionalized polyimides with intrinsic microporosity

KAUST Repository

Ma, Xiaohua

2012-05-08

A newly designed diamine monomer, 3,3,3′,3′-tetramethyl-1, 1′-spirobisindane-5,5′-diamino-6,6′-diol, was successfully used to synthesize two types of polyimides for membrane-based gas separation applications. The novel polymers integrate significant microporosity and polar hydroxyl groups, showing the combined features of polymers of intrinsic microporosity (PIMs) and functional polyimides (PIs). They possess high thermal stability, good solubility, and easy processability for membrane fabrication; the resulting membranes exhibit good permeability owing to the intrinsic microporosity introduced by the highly contorted PIM segments as well as high CO 2/CH 4 selectivity that arises from the hydroxyl groups. The membranes show CO 2/CH 4 selectivities of >20 when tested with a 1:1 CO 2/CH 4 mixture for feed pressures up to 50 bar. In addition, the incorporation of hydroxyl groups and microporosity in the polymers enhances their affinity to water, leading to remarkable water sorption capacities of up to 22 wt % at 35 °C and 95% relative humidity. © 2012 American Chemical Society.

Optimal choice of pH for toxicity and bioaccumulation studies of ionizing organic chemicals

DEFF Research Database (Denmark)

Rendal, Cecilie; Kusk, Kresten Ole; Trapp, Stefan

2011-01-01

a dynamic flux model based on the Fick-Nernst-Planck diffusion equation known as the cell model. The cell model predicts that bases with delocalized charges may in some cases show declining bioaccumulation with increasing pH. Little information is available for amphoteric and zwitterionic compounds; however...

Toxicity and bioaccumulation of sediment-associated silvernanoparticles in the estuarine polychaete, Nereis (Hediste) diversicolor

DEFF Research Database (Denmark)

Cong, Yi; Banta, Gary Thomas; Selck, Henriette

2014-01-01

damage (comet assay tail moment and tail DNA intensity %) of Nereis coelomocytes increased in a concentration-dependent manner in all three Ag treatments. Ag NP treatments were more toxic than aqueous Ag for all toxicity endpoints, even though bioaccumulation did not differ significantly among Ag forms...

Comprehensive database of Manufactured Gas Plant tars. Part C. Heterocyclic and hydroxylated polycyclic aromatic hydrocarbons.

Science.gov (United States)

Gallacher, Christopher; Thomas, Russell; Lord, Richard; Kalin, Robert M; Taylor, Chris

2017-08-15

Coal tars are a mixture of organic and inorganic compounds that were by-products from the manufactured gas and coke making industries. The tar compositions varied depending on many factors such as the temperature of production and the type of retort used. For this reason a comprehensive database of the compounds found in different tar types is of value to understand both how their compositions differ and what potential chemical hazards are present. This study focuses on the heterocyclic and hydroxylated compounds present in a database produced from 16 different tars from five different production processes. Samples of coal tar were extracted using accelerated solvent extraction (ASE) and derivatized post-extraction using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS). The derivatized samples were analysed using two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC/TOFMS). A total of 865 heterocyclic compounds and 359 hydroxylated polycyclic aromatic hydrocarbons (PAHs) were detected in 16 tar samples produced by five different processes. The contents of both heterocyclic and hydroxylated PAHs varied greatly with the production process used, with the heterocyclic compounds giving information about the feedstock used. Of the 359 hydroxylated PAHs detected the majority would not have been be detected without the use of derivatization. Coal tars produced using different production processes and feedstocks yielded tars with significantly different heterocyclic and hydroxylated contents. The concentrations of the individual heterocyclic compounds varied greatly even within the different production processes and provided information about the feedstock used to produce the tars. The hydroxylated PAH content of the samples provided important analytical information that would otherwise not have been obtained without the use of derivatization and GCxGC/TOFMS. Copyright © 2017 John Wiley & Sons, Ltd.

Oxidative transformation of polybrominated diphenyl ether congeners (PBDEs) and of hydroxylated PBDEs (OH-PBDEs).

Science.gov (United States)

Moreira Bastos, Patricia; Eriksson, Johan; Vidarson, Jenny; Bergman, Ake

2008-10-01

The historical and widespread use of polybrominated diphenyl ethers (PBDEs) as flame retardants in consumer products worldwide has caused PBDEs to now be regarded as pervasive environmental contaminants. Most recently, hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have emerged as environmentally relevant due to reports of their natural production and metabolism. An important parameter for assessing the environmental impact of a chemical substance is persistence. By formulating the concept that persistence is the result of the substance's physicochemical properties and chemical reactivity, Green and Bergman have proposed a new methodology to determine the inherent persistence of a chemical. If persistence could be predicted by straightforward methods, substances with this quality could be screened out before large-scale production/manufacturing begins. To provide data to implement this concept, we have developed new methodologies to study chemical transformations through photolysis; hydrolysis, substitution, and elimination; and via oxidation. This study has focused on adapting an oxidative reaction method to be applicable to non-water soluble organic pollutants. PBDEs and one MeO-PBDE were dissolved in tetrahydrofuran/methanol and then diluted in alkaline water. The OH-PBDEs were dissolved in alkaline water prior to reaction. The oxidation degradation reaction was performed at 50 degrees C using potassium permanganate as described elsewhere. The pH was maintained at 7.6 with disodium hydrogen phosphate and barium hydrogen phosphate, the latter also serving as a trapping agent for manganate ions. The oxidation reactions were monitored by high-performance liquid chromatography and reaction rates were calculated. The OH-PBDEs have very fast oxidative transformation rates compared to the PBDEs. The reaction rates seem to be primarily dependent on substitution pattern of the pi-electron-donating bromine substituents and of bromine content. There are

Bioaccumulation, toxicokinetics, and effects of copper from sediment spiked with aqueous Cu, nano-CuO, or micro-CuO in the deposit-feeding snail, Potamopyrgus antipodarum

DEFF Research Database (Denmark)

Pang, Chengfang; Selck, Henriette; Banta, Gary Thomas

2013-01-01

The present study examined the relative importance of copper (aqueous Cu and CuO particles of different sizes) added to sediment to determine the bioaccumulation, toxicokinetics, and effects in the deposit feeder Potamopyrgus antipodarum. In experiment 1, the bioaccumulation of Cu (240 mg Cu/g dr...

Comparative investigation of toxicity and bioaccumulation of Cd-based quantum dots and Cd salt in freshwater plant Lemna minor L.

Science.gov (United States)

Modlitbová, Pavlína; Novotný, Karel; Pořízka, Pavel; Klus, Jakub; Lubal, Přemysl; Zlámalová-Gargošová, Helena; Kaiser, Jozef

2018-01-01

The purpose of this study was to determine the toxicity of two different sources of cadmium, i.e. CdCl 2 and Cd-based Quantum Dots (QDs), for freshwater model plant Lemna minor L. Cadmium telluride QDs were capped with two coating ligands: glutathione (GSH) or 3-mercaptopropionic acid (MPA). Growth rate inhibition and final biomass inhibition of L. minor after 168-h exposure were monitored as toxicity endpoints. Dose-response curves for Cd toxicity and EC50 168h values were statistically evaluated for all sources of Cd to uncover possible differences among the toxicities of tested compounds. Total Cd content and its bioaccumulation factors (BAFs) in L. minor after the exposure period were also determined to distinguish Cd bioaccumulation patterns with respect to different test compounds. Laser-Induced Breakdown Spectroscopy (LIBS) with lateral resolution of 200µm was employed in order to obtain two-dimensional maps of Cd spatial distribution in L. minor fronds. Our results show that GSH- and MPA-capped Cd-based QDs have similar toxicity for L. minor, but are significantly less toxic than CdCl 2 . However, both sources of Cd lead to similar patterns of Cd bioaccumulation and distribution in L. minor fronds. Our results are in line with previous reports that the main mediators of Cd toxicity and bioaccumulation in aquatic plants are Cd 2+ ions dissolved from Cd-based QDs. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata

Science.gov (United States)

Lee, J.-S.; Lee, B.-G.; Yoo, H.; Koh, C.-H.; Luoma, S.N.

2001-01-01

A laboratory bioassay determined the relative contribution of various pathways of Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata exposed to moderately contaminated sediments. Juvenile worms were exposed for 25 d to experimental sediments containing 5 different reactive sulfide (acid volatile sulfides, AVS) concentrations (1 to 30 ??mol g-1), but with constant Ag, Cd, and Zn concentrations of 0.1, 0.1 and 7 ??mol g-1, respectively. The sediments were supplemented with contaminated food (TetraMin??) containing 3 levels of Ag-Cd-Zn (uncontaminated, 1?? or 5??1 metal concentrations in the contaminated sediment). The results suggest that bioaccumulation of Ag, Cd and Zn in the worms occurred predominantly from ingestion of contaminated sediments and contaminated supplementary food. AVS or dissolved metals (in porewater and overlying water) had a minor effect on bioaccumulation of the 3 metals in most of the treatments. The contribution to uptake from the dissolved source was most important in the most oxic sediments, with maximum contributions of 8% for Ag, 30% for Cd and 20% for Zn bioaccumulation. Sediment bioassays where uncontaminated supplemental food is added could seriously underestimate metal exposures in an equilibrated system; N. arenaceodentata feeding on uncontaminated food would be exposed to 40-60% less metal than if the food source was equilibrated (as occurs in nature). Overall, the results show that pathways of metal exposure are dynamically linked in contaminated sediments and shift as external geochemical characteristics and internal biological attributes vary.

Pentachlorophenol (PCP) bioaccumulation and effect on heat production on salmon eggs at different stages of development

Energy Technology Data Exchange (ETDEWEB)

Maeenpaeae, Kimmo A.; Penttinen, Olli-Pekka; Kukkonen, Jussi V.K

2004-05-28

In this study, pentachlorophenol (PCP) bioaccumulation and its effect on heat dissipation was studied in eggs of the lake salmon (Salmo salar m. sebago). In bioaccumulation studies, the eggs were exposed to low concentrations (0.051-0.056 {mu}mol/l, 13.583-14.915) of waterborne [{sup 14}C]-labeled PCP at two developmental stages: (1) 3 weeks after fertilization, and (2) just before hatching. The effect of PCP on egg heat dissipation was measured by a microcalorimeter after exposing the eggs to gradual concentrations (0-0.992 {mu}mol/l) of PCP for 48 h. After both the bioaccumulation and heat dissipation experiments, the eggs were dissected and the concentrations of PCP in tissue were determined separately for eggshell, yolk and embryo. The bioaccumulation studies showed that PCP accumulates more in the eggs at the late developmental stage. Bioconcentration factors (BCF) for different tissues were 3-42 times higher for the eggs at the late developmental stage compared with the eggs that were incubated only for 3 weeks. In early developmental stage, the eggshell adsorbs a large portion of the chemical. In late developmental stage, the actual embryo accumulated both proportionately and totally more than other dissected tissues in the beginning of the exposure, but eventually the yolk accumulated highest total amount of the chemical. A probable reason for the higher PCP body burden in the late developmental stage is that the respiration rate and metabolic activity of the embryo increases as it grows. The salmon eggs responded to an exposure to PCP with an elevated rate of heat dissipation. The threshold concentration above which the embryo heat dissipation was amplified was 29.64 {mu}mol/kg embryo wet weight (ww) or 0.28 {mu}mol/l. The highest embryo heat production was measured at the exposure concentration of 0.992 {mu}mol/l. At higher exposure concentrations the heat dissipation decreased. The basic findings of the study are that PCP accumulates in growing embryonic

Bioaccumulation factors and the steady state assumption for cesium isotopes in aquatic foodwebs near nuclear facilities.

Science.gov (United States)

Rowan, D J

2013-07-01

Steady state approaches, such as transfer coefficients or bioaccumulation factors, are commonly used to model the bioaccumulation of (137)Cs in aquatic foodwebs from routine operations and releases from nuclear generating stations and other nuclear facilities. Routine releases from nuclear generating stations and facilities, however, often consist of pulses as liquid waste is stored, analyzed to ensure regulatory compliance and then released. The effect of repeated pulse releases on the steady state assumption inherent in the bioaccumulation factor approach has not been evaluated. In this study, I examine the steady state assumption for aquatic biota by analyzing data for two cesium isotopes in the same biota, one isotope in steady state (stable (133)Cs) from geologic sources and the other released in pulses ((137)Cs) from reactor operations. I also compare (137)Cs bioaccumulation factors for similar upstream populations from the same system exposed solely to weapon test (137)Cs, and assumed to be in steady state. The steady state assumption appears to be valid for small organisms at lower trophic levels (zooplankton, rainbow smelt and 0+ yellow perch) but not for older and larger fish at higher trophic levels (walleye). Attempts to account for previous exposure and retention through a biokinetics approach had a similar effect on steady state, upstream and non-steady state, downstream populations of walleye, but were ineffective in explaining the more or less constant deviation between fish with steady state exposures and non-steady state exposures of about 2-fold for all age classes of walleye. These results suggest that for large, piscivorous fish, repeated exposure to short duration, pulse releases leads to much higher (137)Cs BAFs than expected from (133)Cs BAFs for the same fish or (137)Cs BAFs for similar populations in the same system not impacted by reactor releases. These results suggest that the steady state approach should be used with caution in any

MLS/Aura L2 Hydroxyl (OH) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2OH is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydroxyl derived from radiances measured by the THz radiometer. The current version is 2.2....

Diatom. A potential bio-accumulator of gold

International Nuclear Information System (INIS)

Chakraborty, N.; Pal, R.; Ramaswami, A.; Nayak, D.; Lahiri, S.

2006-01-01

The bioaccumulation of gold in trace concentration by Nitzschia obtusa and Navicula minima, two members of bacillariophyceae, has been studied. It has been observed that Nitzschia obtusa showed better accumulation of gold in acidic pH in comparison to neutral and basic pH. Maximum accumulation was observed with 1 mg x kg -1 or less gold concentration. However, the accumulation by the living cells was reduced when the matrix concentration was higher. Navicula minima, on the other hand, found to be a better accumulator of gold in wide ranges of pH and substrate concentration of the media. It was also inferred that the gold accumulation by diatom was mainly due to adsorption by biosilica (siliceous frustules of dead diatom cells). Accumulated gold was recovered with conc. HNO 3 . (author)

Microbial carbonylation and hydroxylation of 20(R)-panaxadiol by Aspergillus niger.

Science.gov (United States)

Yan, Bin; Chen, Zhihua; Zhai, Xuguang; Yin, Guibo; Ai, Yafei; Chen, Guangtong

2018-04-01

20(R)-panaxadiol (PD) was metabolised by the fungus Aspergillus niger AS 3.3926 to its C-3 carbonylated metabolite and five other hydroxylated metabolites (1-6). Their structures were elucidated as 3-oxo-20(R)-panaxadiol (1), 3-oxo-7β-hydroxyl- 20(R)-panaxadiol (2), 3-oxo-7β,23α-dihydroxyl-20(R)-panaxadiol (3), 3,12-dioxo- 7β,23β-dihydroxyl-20(R)-panaxadiol (4), 3-oxo-1α,7β-dihydroxyl-20(R)-panaxadiol (5) and 3-oxo-7β,15β-dihydroxyl-20(R)-panaxadiol (6) by spectroscopic analysis. Among them, compounds 2-6 were new compounds. Pharmacological studies revealed that compound 6 exhibited significant anti-hepatic fibrosis activity.

Linkage between speciation of Cd in mangrove sediment and its bioaccumulation in total soft tissue of oyster from the west coast of India.

Science.gov (United States)

Chakraborty, Parthasarathi; Ramteke, Darwin; Gadi, Subhadra Devi; Bardhan, Pratirupa

2016-05-15

This study established a mechanistic linkage between Cd speciation and bioavailability in mangrove system from the west coast of India. High bioaccumulation of Cd was found in the oyster (Crassostrea sp.) even at low Cd loading in the bottom sediment. Bioaccumulation of Cd in the oyster gradually increased with the increasing concentrations of water soluble, exchangeable and carbonate/bicarbonate forms of Cd in the sediments. Fe/Mn oxyhydroxide phase was found to control Cd bioavailability in the sediment system. Cd-associated with sedimentary organic matter was bioavailable and organic ligands in the sediments were poor chelating agents for Cd. This study suggests that bioaccumulation of Cd in oyster (Crassostrea sp.) depends not on the total Cd concentration but on the speciation of Cd in the system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of some radionuclides from water by bioaccumulation

Energy Technology Data Exchange (ETDEWEB)

Miskovic, D.; Conkic, L.; Dalmacija, B.; Gantar, M. (Trg D. Obradvica 3, Novi Sad (Yugoslavia). Faculty of Sciences)

1992-01-01

First objective of this study was to investigate the application of biologically activated carbon (BAC) as well as its comparison to adsorption, with the aim of removing some radionuclides from water. The isotopes Cs[sup 134] and Cs[sup 137] were bioaccumulated by BAC up to 50%, while the I[sup 131] isotope was only physicochemically adsorbed (about 40%). Also, the process of radionuclides (Cs[sup 137], Ce[sup 139], Co[sup 57], Co[sup 60]) fixation on blue-green algae (Nostoc sp.) was investigated. The kinetics of the removal of these radionuclides from water was recorded. It was found that after a contact period of about half an hour 40-70% of the activity was removed. (Author).

Bioaccumulation trends of arsenic and antimony in a freshwater ecosystem affected by mine drainage

Science.gov (United States)

Dovick, Meghan A.; Kulp, Thomas R.; Arkle, Robert .; Pilliod, David S.

2015-01-01

We compared As and Sb bioaccumulation and biomagnification when these metalloids co-occurred at varying environmental concentrations in a stream and wetlands near a contaminated mine site in Idaho (USA). We measured As and Sb concentrations in water and substrate samples, and in tissues of organisms representing several trophic levels. Bioaccumulation of both As and Sb was observed in stream organisms with the following trend of bio-diminution with increasing trophic level: primary producers > tadpoles > macroinvertebrates > trout. We also note reductions in metalloid concentrations in one of two stream remediation reaches engineered within the past 17 years to ameliorate metalloid contamination in the stream. Several wetlands contained thick microbial mats and were highly populated with boreal toad tadpoles that fed on them. The mats were extremely contaminated (up to 76 564 mg kg–1 As and 675 mg kg–1 Sb) with amorphous As- and Sb-bearing minerals that we interpret as biogenic precipitates from geomicrobiological As- and Sb-cycling. Ingested mat material provided a direct source of metalloids to tadpoles, and concentrations of 3867 mg kg–1 (As) and 375 mg kg–1 (Sb) reported here represent the highest whole body As and Sb levels ever reported in living tadpoles. The bulk of tadpole metalloid burden remained in the gut despite attempts to purge the tadpoles prior to analysis. This study adds to a number of recent investigations reporting bioaccumulation, but not biomagnification, of As and Sb in food webs. Moreover, our results suggest that tadpoles, in particular, may be more resistant to metalloid contamination than previously assumed.

A dynamic and mechanistic model of PCB bioaccumulation in the European hake ( Merluccius merluccius)

Science.gov (United States)

Bodiguel, Xavier; Maury, Olivier; Mellon-Duval, Capucine; Roupsard, François; Le Guellec, Anne-Marie; Loizeau, Véronique

2009-08-01

Bioaccumulation is difficult to document because responses differ among chemical compounds, with environmental conditions, and physiological processes characteristic of each species. We use a mechanistic model, based on the Dynamic Energy Budget (DEB) theory, to take into account this complexity and study factors impacting accumulation of organic pollutants in fish through ontogeny. The bioaccumulation model proposed is a comprehensive approach that relates evolution of hake PCB contamination to physiological information about the fish, such as diet, metabolism, reserve and reproduction status. The species studied is the European hake ( Merluccius merluccius, L. 1758). The model is applied to study the total concentration and the lipid normalised concentration of 4 PCB congeners in male and female hakes from the Gulf of Lions (NW Mediterranean sea) and the Bay of Biscay (NE Atlantic ocean). Outputs of the model compare consistently to measurements over the life span of fish. Simulation results clearly demonstrate the relative effects of food contamination, growth and reproduction on the PCB bioaccumulation in hake. The same species living in different habitats and exposed to different PCB prey concentrations exhibit marked difference in the body accumulation of PCBs. At the adult stage, female hakes have a lower PCB concentration compared to males for a given length. We successfully simulated these sex-specific PCB concentrations by considering two mechanisms: a higher energy allocation to growth for females and a transfer of PCBs from the female to its eggs when allocating lipids from reserve to eggs. Finally, by its mechanistic description of physiological processes, the model is relevant for other species and sets the stage for a mechanistic understanding of toxicity and ecological effects of organic contaminants in marine organisms.

Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants

International Nuclear Information System (INIS)

Peterson, Sarah H.; Peterson, Michael G.; Debier, Cathy; Covaci, Adrian; Dirtu, Alin C.; Malarvannan, Govindan; Crocker, Daniel E.; Schwarz, Lisa K.; Costa, Daniel P.

2015-01-01

As top predators in the northeast Pacific Ocean, northern elephant seals (Mirounga angustirostris) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N = 24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males, we sampled different adults and sub-adults before (N = 14) and after (N = 15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ∑ DDTs and ∑ PCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ∑ DDT and ∑ PBDEs were highly correlated in blubber and serum. While ∑ PCBs were highly correlated with ∑ DDTs and ∑ PBDEs in blubber and serum for males, ∑ PCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ∑ DDTs, ∑ PBDEs, MeO-BDE 47, as well as the ratio of ∑ DDTs to ∑ PCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations of ∑ DDTs and ∑ PBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in 13 C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in deep

Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Peterson, Sarah H., E-mail: sarahpeterson23@gmail.com [Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 (United States); Peterson, Michael G. [Department of Environmental Science, Policy and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA 94720 (United States); Debier, Cathy [Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve (Belgium); Covaci, Adrian [Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Dirtu, Alin C. [Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Department of Chemistry, “Al. I. Cuza” University of Iasi, 700506 Iasi (Romania); Malarvannan, Govindan [Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk (Belgium); Crocker, Daniel E. [Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928 (United States); Schwarz, Lisa K. [Institute of Marine Sciences, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 (United States); Costa, Daniel P. [Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060 (United States)

2015-11-15

As top predators in the northeast Pacific Ocean, northern elephant seals (Mirounga angustirostris) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N = 24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males, we sampled different adults and sub-adults before (N = 14) and after (N = 15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ∑ DDTs and ∑ PCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ∑ DDT and ∑ PBDEs were highly correlated in blubber and serum. While ∑ PCBs were highly correlated with ∑ DDTs and ∑ PBDEs in blubber and serum for males, ∑ PCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ∑ DDTs, ∑ PBDEs, MeO-BDE 47, as well as the ratio of ∑ DDTs to ∑ PCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations of ∑ DDTs and ∑ PBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in {sup 13}C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in

Spatial analysis of polybrominated diphenylethers (PBDEs) and polybrominated biphenyls (PBBs) in fish collected from UK and proximate marine waters.

Science.gov (United States)

Zhihua, Li; Panton, S; Marshall, Lisa; Fernandes, A; Rose, M; Smith, F; Holmes, Mel

2018-03-01

Some commonly consumed marine fish species are considered to display a higher risk of bio-accumulating organic environmental contaminants such as PBDEs. As part of a study to investigate the spatial distribution of these contaminants, data on polybrominated diphenlyethers (PBDEs) and polybrominated biphenyls (PBBs) were collected and analysed by introducing a web-based resource which enables efficient spatial, species and concentration level representations. Furthermore, hierarchical cluster analyses permits correlations within the data to be predicted. The data provide current information on levels of PBDE and PBB occurrence, allowing identification of locations that show higher contaminant levels. 135 fish samples of various species were analysed from UK marine waters, but encompassing the waters around Norway in the North and to the Algarve in the South. PBDEs were observed in all samples with the majority of measured congeners being detected. The concentrations ranged from 0.087 μg/kg to 8.907 μg/kg whole weight (ww) for the sum of all measured PBDE congeners. PBBs occurred less frequently showing a corresponding range of <0.02 μg/kg to 0.97 μg/kg ww for the sum of seven PBB congeners. Concentrations vary depending on species and locations where landed, e.g. PBBs occurred more frequently and at higher levels in grey mullet from French waters. The high frequency of PBDE occurrence makes it prudent to continue the monitoring of these commonly consumed marine fish species. The web-based resource provides a flexible and efficient tool for assessors and policy-makers to monitor and evaluate levels within caught fish species improving evidenced-based decision processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

International Nuclear Information System (INIS)

Yu, Rui; Ran, Maofei; Wen, Jie; Sun, Wenjing; Chu, Wei; Jiang, Chengfa; He, Zhiwei

2015-01-01

Graphical abstract: - Highlights: • The effect of hydroxylation on CNT to form Chitosan-CNT composites was studied. • The adsorption of Chitosan on CNTs is very weak by electrostatic interactions. • Chitosan loads onto CNT-OH_n via hydrogen-bond interactions. • Chitosan transfers electron to CNT-OH_n and thus improves the reactivity of CNT. - Abstract: The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (E_a_d_s) of CS on the pristine CNT and hydroxylated CNTs (CNT-OH_n, n = 1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OH_n is thermodynamically favored. The E_a_d_s of CS on CNTs was calculated to be −20.387 kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OH_n, E_a_d_s ranges from −20.612 to −37.567 kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OH_n via hydrogen-bond interactions. The CS-CNT-OH_3 is the most sable composite among tested complexes. The energy gap (ΔE_g_a_p) of CS-CNT-OH_3 was calculated less than pristine CNT and CNT-OH_3, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH_3. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Yu, Rui [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China); Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Ran, Maofei [College of Chemistry & Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041, Sichuan (China); Wen, Jie [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan (China); Sun, Wenjing, E-mail: swj_gdmc@163.com [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China); Chu, Wei; Jiang, Chengfa [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); He, Zhiwei, E-mail: zhiweihe688@yahoo.com [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China)

2015-12-30

Graphical abstract: - Highlights: • The effect of hydroxylation on CNT to form Chitosan-CNT composites was studied. • The adsorption of Chitosan on CNTs is very weak by electrostatic interactions. • Chitosan loads onto CNT-OH{sub n} via hydrogen-bond interactions. • Chitosan transfers electron to CNT-OH{sub n} and thus improves the reactivity of CNT. - Abstract: The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (E{sub ads}) of CS on the pristine CNT and hydroxylated CNTs (CNT-OH{sub n}, n = 1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OH{sub n} is thermodynamically favored. The E{sub ads} of CS on CNTs was calculated to be −20.387 kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OH{sub n}, E{sub ads} ranges from −20.612 to −37.567 kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OH{sub n} via hydrogen-bond interactions. The CS-CNT-OH{sub 3} is the most sable composite among tested complexes. The energy gap (ΔE{sub gap}) of CS-CNT-OH{sub 3} was calculated less than pristine CNT and CNT-OH{sub 3}, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH{sub 3}. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

Exploring the Use of Multimedia Fate and Bioaccumulation Models to Calculate Trophic Magnification Factors (TMFs)

Science.gov (United States)

The trophic magnification factor (TMF) is considered to be a key metric for assessing the bioaccumulation potential of organic chemicals in food webs. Fugacity is an equilibrium criterion and thus reflects the relative thermodynamic status of a chemical in the environment and in ...

Elemental bioaccumulators in air pollution studies

International Nuclear Information System (INIS)

Freitas, M.C.

1995-01-01

K 0 -Based instrumental neutron activation analysis (k 0 INAA) was used to determine the concentrations of Cr, Fe, Co, Zn, Se, Sb and Hg in the vascular plants Cistus salvifolius and Inula viscosa and in the lichen Parmelia sulcata. The samples were collected in the neighbourhood of industrial complexes. The elemental accumulation in the vascular plants and the lichen are compared to optimize the choice of the bioaccumulator. It is concluded that P.sulcata seems to be the best accumulator of the three species for the element studied; Cistus salvifolius is sensitive to the contents of Zn, Fe, Cr and Sb in the air; Inula viscosa seems to accumulate Fe, Sb, Co, Cr and Zn. Nevertheless, it is concluded that lichen is a good air pollution indicator, while the vascular plants are not due to the large seasonal variations found in the elemental concentrations. (author) 11 refs.; 7 figs.; 2 tabs

Stability, electrochemical behaviors and electronic structures of iron hydroxyl-phosphate

International Nuclear Information System (INIS)

Wang Zhongli; Sun Shaorui; Li Fan; Chen Ge; Xia Dingguo; Zhao Ting; Chu Wangsheng; Wu Ziyu

2010-01-01

Iron hydroxyl-phosphate with a uniform spherical particle size of around 1 μm, a compound of the type Fe 2-y □ y (PO 4 )(OH) 3-3y (H 2 O) 3y-2 (where □ represents a vacancy), has been synthesized by hydrothermal methods. The particles are composed of spheres of diameter -1 and 120 mAh g -1 at current densities of 170 mA g -1 and 680 mA g -1 , respectively. The stability of crystal structure of this material was studied by TGA and XRD which show that the material remains stable at least up to the temperature 200 deg. C. Investigation of the electronic structure of the iron hydroxyl-phosphate by GGA + U calculation has indicated that it has a better electronic conductivity than LiFePO 4 .

Mercury in western North America: A synthesis of environmental contamination, fluxes, bioaccumulation, and risk to fish and wildlife

Science.gov (United States)

Eagles-Smith, Collin A.; Wiener, James G.; Eckley, Chris S.; Willacker, James J.; Evers, David C.; Marvin-DiPasquale, Mark C.; Obrist, Daniel; Fleck, Jacob; Aiken, George R.; Lepak, Jesse M.; Jackson, Allyson K.; Webster, Jackson; Stewart, Robin; Davis, Jay; Alpers, Charles N.; Ackerman, Joshua T.

2016-01-01

Western North America is a region defined by extreme gradients in geomorphology and climate, which support a diverse array of ecological communities and natural resources. The region also has extreme gradients in mercury (Hg) contamination due to a broad distribution of inorganic Hg sources. These diverse Hg sources and a varied landscape create a unique and complex mosaic of ecological risk from Hg impairment associated with differential methylmercury (MeHg) production and bioaccumulation. Understanding the landscape-scale variation in the magnitude and relative importance of processes associated with Hg transport, methylation, and MeHg bioaccumulation requires a multidisciplinary synthesis that transcends small-scale variability. The Western North America Mercury Synthesis compiled, analyzed, and interpreted spatial and temporal patterns and drivers of Hg and MeHg in air, soil, vegetation, sediments, fish, and wildlife across western North America. This collaboration evaluated the potential risk from Hg to fish, and wildlife health, human exposure, and examined resource management activities that influenced the risk of Hg contamination. This paper integrates the key information presented across the individual papers that comprise the synthesis. The compiled information indicates that Hg contamination is widespread, but heterogeneous, across western North America. The storage and transport of inorganic Hg across landscape gradients are largely regulated by climate and land-cover factors such as plant productivity and precipitation. Importantly, there was a striking lack of concordance between pools and sources of inorganic Hg, and MeHg in aquatic food webs. Additionally, water management had a widespread influence on MeHg bioaccumulation in aquatic ecosystems, whereas mining impacts where relatively localized. These results highlight the decoupling of inorganic Hg sources with MeHg production and bioaccumulation. Together the findings indicate that developing

Heavy metal bio-accumulation in tissues of sturgeon species of the Lower Danube River, Romania

Directory of Open Access Journals (Sweden)

ONĂRĂ Dalia Florentina

2013-12-01

Full Text Available This study investigates bio-accumulation of heavy metals in tissues of sturgeons of the North-Western Black Sea and Lower Danube River (LDR. Samples (10 – 30 gr of liver, muscle, fat, gonads and skin tissues collected in October 2003 from 21 adult specimens of three sturgeon species: Acipenser stellatus (10, A. gueldenstaedtii (2, and Huso huso (9 were analysed for content in Cd, Cu, Zn, Pb, Mn, Fe and Ni, using VARIAN Spectra A100. The highest concentrations of Zn, Cu and Cd were found in liver and the smallest in muscles of sturgeons. The highest heavy metal content was detected in tissues of stellate sturgeons, followed by Russian sturgeons. In all three species Cd and Cu content of the liver as well as of the stellate sturgeon muscle surpassed the admitted limits for human consumption (Cd – 0.05; Zn - 50; Cu – 5.0; Pb – 0.3 [mg / kg wet weight]. In view of a future re-opening of the commercial fishing of wild sturgeons it is strongly recommended testing the heavy metal level prior delivering sturgeon products to the market. Avoiding human consumption of liver of sturgeons captured in the LDR is strongly recommended as well. In the case of Cd a bio-accumulation with age of sturgeons was visible. In all species males seem to accumulate more heavy metals in their tissues. We explain this as effect of more frequent spawning migration of males in the LDR, the major contamination source. Beluga sturgeons show less heavy metal bio-accumulation of tissues.

Effects of Selenite on Unicellular Green Microalga Chlorella pyrenoidosa: Bioaccumulation of Selenium, Enhancement of Photosynthetic Pigments, and Amino Acid Production.

Science.gov (United States)

Zhong, Yu; Cheng, Jay J

2017-12-20

Microalgae were studied as function bioaccumulators of selenium (Se) for food and feed supplement. To investigate the bioaccumulation of Se and its effects on the unicellular green alga Chlorella pyrenoidosa, the algal growth curve, fluorescence parameters, antioxidant enzyme activity, and fatty acid and amino acid profiles were examined. We found that Se at low concentrations (≤40 mg L -1 ) positively promoted algal growth and inhibited lipid peroxidation and intracellular reactive oxygen species. The antioxidative effect was associated with an increase in the levels of glutathione peroxidase, catalase, linolenic acid, and photosynthetic pigments. Meanwhile, a significant increase in amino acid and organic Se content was also detected in the microalgae. In contrast, we found opposite effects in C. pyrenoidosa exposed to >60 mg L -1 Se. The antioxidation and toxicity appeared to be correlated with the bioaccumulation of excess Se. These results provide a better understanding of the effect of Se on green microalgae, which may help in the development of new technological applications for the production of Se-enriched biomass from microalgae.

Bile acid synthesis in man. In vivo activity of the 25-hydroxylation pathway

International Nuclear Information System (INIS)

Duane, W.C.; Pooler, P.A.; Hamilton, J.N.

1988-01-01

During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side-chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. We have previously shown in the rat that the contribution of the 25-hydroxylation pathway can be quantitated in vivo by measuring production of [ 14 C]acetone from [ 14 C]26-cholesterol. In the present study, we adapted this method to human subjects. 4 d after oral administration of 100 microCi of [ 14 C]26-cholesterol and 1 d after beginning a constant infusion of 16.6 mumol/min unlabeled acetone, three men and two women underwent breath collections. Expired acetone was trapped and purified as the 2,4 dinitrophenylhydrazine derivative. 14 CO 2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied by the acetone infusion rate to calculate production of [ 14 C]acetone. [ 14 C]Acetone production averaged 4.9% of total release of 14 C from [ 14 C]26-cholesterol, estimated by 14 CO2 output. The method was validated by showing that [ 14 C]acetone production from [ 14 C]isopropanol averaged 86.9% of the [ 14 C]-isopropanol infusion rate. We conclude that in man, as in the rat, the 25-hydroxylation pathway accounts for less than 5% of bile acid synthesis

Structure-based engineering of steroidogenic CYP260A1 for stereo- and regioselective hydroxylation of progesterone

NARCIS (Netherlands)

Khatri, Yogan; Jóźwik, Ilona K; Ringle, Michael; Ionescu, Irina Alexandra; Litzenburger, Martin; Hutter, Michael Christopher; Thunnissen, Andy-Mark W H; Bernhardt, Rita

The production of regio- and stereoselectively hydroxylated steroids is of high pharmaceutical interest and can be achieved by cytochrome P450-based biocatalysts. CYP260A1 from Sorangium cellulosum strain So ce56 catalyzes hydroxylation of C19 or C21 steroids at the very unique 1-position. However,

The effects of experimental reservoir creation on the bioaccumulation of methylmercury and reproductive success of tree swallows (Tachycineta bicolor).

Science.gov (United States)

Gerrard, P M; St Louis, V L

2001-04-01

Reservoir creation results in decomposition of flooded organic matter and increased rates of mercury methylation. Methylmercury (MeHg), the most toxic form of mercury, bioaccumulates through aquatic food webs. Our objective was to quantify the transfer of MeHg from aquatic food webs into terrestrial organisms. We examined rates of MeHg bioaccumulation in an insectivorous songbird, the tree swallow, breeding near an experimentally created reservoir. We also determined the impact of flooding and MeHg bioaccumulation on the reproductive success of these birds. Mean MeHg burdens in nestling swallows from near the experimental reservoir increased from 1,210 +/- 150 ng before flooding to 2,200 +/- 102 ng after flooding. Postflood MeHg concentrations in both the body and feathers of the birds were significantly greater than preflood MeHg concentrations. Although MeHg burdens in swallows were elevated in postflood years, we found no overt toxicological affects. An increase in dipteran productivity (the primary food source of tree swallows) after reservoir creation resulted in earlier nest initiation, larger eggs, and faster growth rates of wing and bill length in nestlings raised during postflood years.

Bioaccumulation and toxicity of zinc in the green alga, Cladophora glomerata.

Science.gov (United States)

McHardy, B M; George, J J

1990-01-01

The bioaccumulation and toxicity of zinc in Cladophora glomerata from two populations in the River Roding, Essex, UK, were examined in experimental laboratory flowing-water channels. Plants were subjected to zinc concentrations ranging from 0 to 4.0 mg litre(-1) at current velocities of 20-33 cm s(-1) for up to 3 h. Zinc in algal tissue was then quantified and toxicity was assessed by the ability of the alga to grow in a recovery medium after the experimental treatment. There was little difference in zinc bioaccumulation between Cladophora from the site showing mild organic pollution and that from the site subjected to considerable inputs from urban and motorway runoff. Uptake of zinc increased with increasing concentration in the test solution and was linear and proportional up to 0.4 mg litre(-1). Three stages of uptake were identified with the most dramatic accumulation occurring in the first 10 min. Experimental concentration factors ranged from 1.9-5.2 x 10(3), which were in agreement with those previously obtained in the field. Cellular damage was evident in Cladophora subjected to 0.4 mg litre(-1) zinc, and this increased with increasing zinc concentration, thus leading to the conclusion that, at times, the levels of zinc found in the river could be potentially damaging.

Optimizing fish and stream-water mercury metrics for calculation of fish bioaccumulation factors

Science.gov (United States)

Paul Bradley; Karen Riva Murray; Barbara C. Scudder Elkenberry; Christopher D. Knightes; Celeste A. Journey; Mark A. Brigham

2016-01-01

Mercury (Hg) bioaccumulation factors (BAFs; ratios of Hg in fish [Hgfish] and water[Hgwater]) are used to develop Total Maximum Daily Load and water quality criteria for Hg-impaired waters. Protection of wildlife and human health depends directly on the accuracy of site-specific estimates of Hgfish and Hgwater and the predictability of the relation between these...

Hydroxyl radical scavenging activity of peptide from sea cucumber ...

African Journals Online (AJOL)

enzyme complex, sea cucumber protein hydrolysis was carried out to obtain hydrolysates that have hydroxyl-radical-scavenging activity (HRSA). The hydrolytic process was monitored by HRSA and conditions for this process were optimized as follows: pH 6.5, temperature 35°C, 12 mg enzyme complex in a reaction solution ...

Hydroxylative activity of Aspergillus niger towards androst-4-ene and androst-5-ene steroids.

Science.gov (United States)

Świzdor, Alina; Panek, Anna; Milecka-Tronina, Natalia

2017-10-01

Aspergillus niger, one of fungal species most frequently used for experimental and industrial-scale biotransformations of various organic compounds, is generally known to transform steroids at 16β position. In this work, application of the strain A. niger KCH910 to bioconversion of dehydroepiandrosterone (DHEA), androstenediol and testosterone is described, with emphasis on the metabolic steps leading to the products. Evidence from this study indicated that incubated 5-ene steroids underwent bioconversion within two metabolic pathways: oxidation by the action of 3β-HSD (3β-hydroxysteroid dehydrogenase) to 4-ene steroids, and minor allylic hydroxylation to epimeric 7-alcohols. Further transformation of the 3-oxo-4-ene metabolites resulted in non-selective 16-hydroxylation. It is the first report on an A. niger strain able to introduce not only 16β- but also 16α-hydroxyl function into steroids. Copyright © 2017. Published by Elsevier Inc.

Occurrence of PCDD/F, PCB, PBDE, PFAS, and organotin compounds in fish meal, fish oil and fish feed.

Science.gov (United States)

Suominen, K; Hallikainen, A; Ruokojärvi, P; Airaksinen, R; Koponen, J; Rannikko, R; Kiviranta, H

2011-10-01

We analysed polychlorinated dibenzo-p-dioxins and furans (PCDD/F, dioxins), and polychlorinated biphenyls (PCB) in 13 fish meal, five fish oil, and seven fish feed samples. Polybrominated diphenyl ethers (PBDE), organotin compounds (OTC), and perfluoroalkylated substances (PFAS) were analysed in ten fish meal, two fish oil, and two fish feed samples. All measured TEQ concentrations of PCDD/F and PCB were below the maximum levels set by Directive 2002/32/EC. There was no correlation between concentrations of WHOPCDD/F-TEQ and indicator PCB in our samples. The most common congeners among PBDEs were BDE-47 and BDE-100. BDE-209 was present in five fish meals of the ten analysed. Tributyltin (TBT) was the predominant congener in all samples except in three fish meals, where monobutyltin (MBT) was the major congener. Perfluorooctane sulphonate (PFOS) was the predominant congener in six fish meals of the ten analysed. There was large variation in concentrations and congener distributions of the studied compounds between our samples. Our results underline a need to pay special attention to the origin and purity of feed raw material of marine origin. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hydroxyl Radical-Mediated Novel Modification of Peptides: N-Terminal Cyclization through the Formation of α-Ketoamide.

Science.gov (United States)

Lee, Seon Hwa; Kyung, Hyunsook; Yokota, Ryo; Goto, Takaaki; Oe, Tomoyuki

2015-01-20

The hydroxyl radical-mediated oxidation of peptides and proteins constitutes a large group of post-translational modifications that can result in structural and functional changes. These oxidations can lead to hydroxylation, sulfoxidation, or carbonylation of certain amino acid residues and cleavage of peptide bonds. In addition, hydroxyl radicals can convert the N-terminus of peptides to an α-ketoamide via abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. In the present study, we identified N-terminal cyclization as a novel modification mediated by a hydroxyl radical. The reaction of angiotensin (Ang) II (DRVYIHPF) and the hydroxyl radical generated by the Cu(II)/ascorbic acid (AA) system or UV/hydrogen peroxide system produced N-terminal cyclized-Ang II (Ang C) and pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The structure of Ang C was confirmed by mass spectrometry and comparison to an authentic standard. The subsequent incubation of isolated Ang P in the presence of Cu(II)/AA revealed that Ang P was the direct precursor of Ang C. The proposed mechanism involves the formation of a nitrogen-centered (aminyl) radical, which cyclizes to form a five-membered ring containing the alkoxy radical. The subsequent β-scission reaction of the alkoxyl radical results in the cleavage of the terminal CH3CO group. The initial aminyl radical can be stabilized by chelation to the Cu(II) ions. The affinity of Ang C toward the Ang II type 1 receptor was significantly lower than that of Ang II or Ang P. Ang C was not further metabolized by aminopeptidase A, which converts Ang II to Ang III. Hydroxyl radical-mediated N-terminal cyclization was also observed in other Ang peptides containing N-terminal alanine, arginine, valine, and amyloid β 1-11 (DAEFRHDSGYE).

Differential bioaccumulation and translocation patterns in three mangrove plants experimentally exposed to iron. Consequences for environmental sensing.

Science.gov (United States)

Arrivabene, Hiulana Pereira; Campos, Caroline Quenupe; Souza, Iara da Costa; Wunderlin, Daniel Alberto; Milanez, Camilla Rozindo Dias; Machado, Silvia Rodrigues

2016-08-01

Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle were experimentally exposed to increasing levels of iron (0, 10, 20 and 100 mg L(-1) added Fe(II) in Hoagland's nutritive medium). The uptake and translocation of iron from roots to stems and leaves, Fe-secretion through salt glands (Avicennia schaueriana and Laguncularia racemosa) as well as anatomical and histochemical changes in plant tissues were evaluated. The main goal of this work was to assess the diverse capacity of these plants to detect mangroves at risk in an area affected by iron pollution (Vitoria, Espírito Santo, Brazil). Results show that plants have differential patterns with respect to bioaccumulation, translocation and secretion of iron through salt glands. L. racemosa showed the best environmental sensing capacity since the bioaccumulation of iron in both Fe-plaque and roots was higher and increased as the amount of added-iron rose. Fewer changes in translocation factors throughout increasing added-iron were observed in this species. Furthermore, the amount of iron secreted through salt glands of L. racemosa was strongly inhibited when exposed to added-iron. Among three studied species, A. schaueriana showed the highest levels of iron in stems and leaves. On the other hand, Rhizophora mangle presented low values of iron in these compartments. Even so, there was a significant drop in the translocation factor between aerial parts with respect to roots, since the bioaccumulation in plaque and roots of R. mangle increased as iron concentration rose. Moreover, rhizophores of R. mangle did not show changes in bioaccumulation throughout the studied concentrations. So far, we propose L. racemosa as the best species for monitoring iron pollution in affected mangroves areas. To our knowledge, this is the first detailed report on the response of these plants to increasing iron concentration under controlled conditions, complementing existing data on the behavior of the same plants

Oxygen activation at the plasma membrane: relation between superoxide and hydroxyl radical production by isolated membranes.

Science.gov (United States)

Heyno, Eiri; Mary, Véronique; Schopfer, Peter; Krieger-Liszkay, Anja

2011-07-01

Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.

Heavy Metals Bioaccumulation by Iranian and Australian Earthworms (Eisenia fetida in the Sewage Sludge Vermicomposting

Directory of Open Access Journals (Sweden)

MR Shahmansouri, H Pourmoghadas, AR Parvaresh, H Alidadi

2005-01-01

Full Text Available Vermicomposting of organic waste has an important part to play in an integrated waste management strategy. In this study, the possibility of heavy metals accumulation with two groups of Iranian and Australian earthworms in sewage sludge vermicompost was investigated. Eisenia fetida was the species of earthworms used in the vermicomposting process. The bioaccumulation of Cr, Cd, Pb, Cu, and Zn as heavy metals by Iranian and Australian earthworms was studied. The results indicated that heavy metals concentration decreased with increasing vermicomposting time. Comparison of the two groups of earthworms showed that the Iranian earthworms consumed higher quantities of micronutrients such as Cu and Zn comparing with the Australian earthworms, while the bioaccumulation of non-essential elements such as Cr, Cd, and Pb by the Australian group was higher. The significant decrease in heavy metal concentrations in the final vermicompost indicated the capability of both Iranian and Australian E.fetida species in accumulating heavy metals in their body tissues.

Sensing dissolved sediment porewater concentrations of persistent and bioaccumulative poolutants using disposable solid-phase microextraction fibers

NARCIS (Netherlands)

Mayer, P.; Vaes, W.H.J.; Wijnker, F.; Legierse, K.C.H.M.; Kraaij, R.H.; Tolls, J.; Hermens, J.L.M.

2000-01-01

Polymer coated glass fibers were applied as disposable samplers to measure dissolved concentrations of persistent and bioaccumulative pollutants (PBPs) in sediment porewater. The method is called matrix solid-phase microextraction (matrix-SPME), because it utilizes the entire sediment matrix as a

An experimental study of hydroxyl in quartz using infrared spectroscopy and ion microprobe techniques

Energy Technology Data Exchange (ETDEWEB)

Rovetta, M. R.; Blacic, J. D.; Hervig, R. L.; Holloway, J. R.

1989-05-10

We have measured the concentrations of hydroxyl, deuterium, Al, Fe, Li,Na, K, and Rb in a natural quartz crystal before and after hydrothermaltreatment at 1.5 GPa and 800/degree/--1050 /degree/C. We employed microbeam infraredspectroscopy and ion probe techniques to avoid impurities trapped in healedcracks and fluid inclusions that might bias a normal bulk analysis.The /ital f//sub H/sub 2// of our experiments were buffered to thehematite-magnetite-(OH)fluid, nickel-nickel oxide-(OH)fluid, oriron-wustite-(OH)fluid phase assemblages. After hydrothermal treatment,the samples contained local concentrations of hydrogen or deuterium ofseveral hundred atoms/10/sup 6/ Si (the starting crystal contained 45 H/10/sup 6/ Si).We did several experiments with Al/sub 2/O/sub 3/ or RbCl added to the sample chargeand found local Al enrichment where the deuterium concentration was highbut no Rb enrichment. Finally, we measured trace elements and hydroxyl in aquartz sample after plastic deformation in a talc furnace assembly; inregions of the sample containing basal and prismatic deformation lamellae(but no visible healed microcracks at 400/times/ optical magnification)hydroxyl had increased to /similar to/200 oO/10/sup 6/ Si with no increase in Al or Fe.Samples enriched in hydroxyl but not Al (including the plastically strainedsample) gave infrared spectra resembling natural amethyst crystals.

Bioaccumulation factor for 32P measured in bluegill, Lepomis macrochirus, and catfish, Ictalurus punctatus

International Nuclear Information System (INIS)

Kahn, B.; Turgeon, K.S.; Martini, D.K.; Dunkerly, S.J.; el-Shinawy, R.M.; Wilson, M.D.

1987-01-01

The ratio of the bioaccumulation factors for 32 P and phosphorus was determined for edible tissue in two species of freshwater fish by measuring the specific activity ( 32 P activity per milligram phosphorus) in muscle relative to feed. The 32 P tracer was added to the feed at a uniform level throughout the study. Feeding was at two levels: ad libitum and at a lower but constant intake per body weight. In the main experiment, bluegill were maintained in a large flow-through tank and sacrificed at approximately weekly intervals for 51 d of 32 P accumulation and 28 d of depuration to compare the specific activity with values predicted with a calculational model. In experiments performed in smaller aquaria, the specific activity in bluegill and catfish muscle was compared at two feeding levels and two temperatures. In addition, unfed fish were exposed to 32 P in water at a known specific activity to determine the extent of phosphorus uptake directly from water. The pattern of specific activity increase and decrease in fish muscle during the accumulation/depuration experiment was consistent with a one-compartment model, so that specific activity ratios at steady state could be predicted from measurements during relatively brief exposures. On this basis, the ratio of the bioaccumulation factors of 32 P and phosphorus in fish feeding ad libitum was 0.081 for bluegill and 0.17 for catfish. Hence, at a mean phosphorus bioaccumulation factor of 70,000, the factors for 32 P are 6000 and 12,000, respectively. The ratios were less at lower phosphorus intakes associated with lower feeding rates; moreover, the lesser value for bluegill occurred at a much lower phosphorus intake than by catfish

Hydrogen bonding analysis of hydroxyl groups in glucose aqueous solutions by a molecular dynamics simulation study

International Nuclear Information System (INIS)

Chen, Cong; Li, Wei Zhong; Song, Yong Chen; Weng, Lin Dong; Zhang, Ning

2012-01-01

Molecular dynamics simulations have been performed to investigate hydrogen bonding characteristics of hydroxyl groups in glucose aqueous solutions with different concentrations. The hydrogen bonding abilities and strength of different O and H atom types have been calculated and compared. The acceptor/donor efficiencies have been predicted and it has been found that: (1) O2-HO2 and O3-HO3 are more efficient intramolecular hydrogen bonding acceptors than donors; (2) O1-HO1, O4-HO4 and O6-HO6 are more efficient intramolecular hydrogen bonding donors than acceptors; (5) O1-HO1 and O6-HO6 are more efficient intermolecular hydrogen bonding acceptors than donors while hydroxyl groups O2-HO2 and O4-HO4 are more efficient intermolecular hydrogen bonding donors than acceptors. The hydrogen bonding abilities of hydroxyl groups revealed that: (1) the hydrogen bonding ability of OH2-H w is larger than that of hydroxyl groups in glucose; (2) among the hydroxyl groups in glucose, the hydrogen bonding ability of O6-HO6 is the largest and the hydrogen bonding ability of O4-HO4 is the smallest; (3) the intermolecular hydrogen bonding ability of O6-HO6 is the largest; (4) the order for intramolecular hydrogen bonding abilities (from large to small) is O2-HO2, O1-HO1, O3-HO3, O6-HO6 and O4-HO4

Hydroxyl and water molecule orientations in trypsin: Comparison to molecular dynamics structures

Energy Technology Data Exchange (ETDEWEB)

McDowell, R.S.; Kossiakoff, A.A. [Genentech, Inc., South San Francisco, CA (United States)

1994-12-31

A comparison is presented of experimentally observed hydroxyl and water hydrogens in trypsin determined from neutron density maps with the results of a 140ps molecular dynamics (MD) simulation. Experimental determination of hydrogen and deuterium atom positions in molecules as large as proteins is a unique capability of neutron diffraction. The comparison addresses the degree to which a standard force-field approach can adequately describe the local electrostatic and van der Waals forces that determine the orientations of these hydrogens. Neutron densities, derived from 2.1{Angstrom} D{sub 2}O-H{sub 2}O difference Fourier maps, provide a database of 27 well-ordered hydroxyl hydrogens. Most of the simulated hydroxyl orientations are within a standard deviation of the experimentally-observed positions, including several examples in which both the simulation and the neutron density indicate that a hydroxyl group is shifted from a {open_quote}standard{close_quote} rotamer. For the most highly ordered water molecules, the hydrogen distributions calculated from the trajectory were in good agreement with neutron density; simulated water molecules that displayed multiple hydrogen bonding networks had correspondingly broadened neutron density profiles. This comparison was facilitated by development of a method to construct a pseudo 2{Angstrom} density map based on the hydrogen atom distributions from the simulation. The degree of disorder of internal water molecules is shown to result primarily from the electrostatic environment surrounding that water molecule as opposed to the cavity size available to the molecule. A method is presented for comparing the discrete observations sampled in a dynamics trajectory with the time- averaged data obtained from X-ray or neutron diffraction studies. This method is particularly useful for statically-disordered water molecules, in which the average location assigned from a trajectory may represent a site of relatively low occupancy.

Literature review on the use of bioaccumulation for heavy metal removal and recovery. Volume 2

Energy Technology Data Exchange (ETDEWEB)

Benemann, J.R. [Benemann (J.R.), Pinole, CA (United States); Wilde, E.W. [Westinghouse Savannah River Co., Aiken, SC (United States)

1991-02-01

Bioaccumulation of metals by microbes -- `` bioremoval`` -- is a powerful new technology for the concentration, recovery, and removal of toxic heavy metals and radionuclides from waste streams and contaminated environments. Algae are particularly well suited for metal bioremoval. A recent commercial application of bioremoval utilizes inert (dead) immobilized microalgae biomass as ion exchange materials for the removal of heavy metals from industrial waste waters. Also, living microalgal cultures have been used to remove metals from mine effluents. Microbial cells and biomass can bioaccumulate metals and radionuclides by a large variety of mechanisms, both dependent and independent of cell metabolism. Microbial cell walls can act as ion exchange and metal complexation agents. Heavy metals can precipitate and even crystallize on cell surfaces. Metabolically produced hydrogen sulfide or other metabolic products can bioprecipitate heavy metals. Many microbes produce both intra- and extracellular metal complexing agents which could be considered in practical metal removal processes. Bioremoval processes are greatly affected by the microbial species and even strain used, pH, redox potential, temperature, and other conditions under which the microbes are grown. Development of practical applications of bioremoval requires applies research using the particular waste solutions to be treated, or close simulations thereof. From a practical perspective, the selection of the microbial biomass and the process for contacting the microbial biomass with the metal containing solutions are the key issues. Much of the recent commercial R&D has emphasized commercially available, inert, microbial biomass sources as these can be acquired in sufficient quantities at affordable costs. The fundamental research and practical applications of bioaccumulation by microalgae suggests these organisms warrant a high priority in the development of advanced bioremoval processes.

Bioaccumulation factor for I-131 in aquatic biota II fish - tilapia (Tilapia Mossambica)

International Nuclear Information System (INIS)

Garcia, G.F.; Casyao, J.M.; Bautista, E.Rb.

1982-01-01

The study was undertaken to provide local values for an essential parameter in the estimation of the dose contribution of I-131 through ingestion of fresh water fish. The result showed that the tilapia used in the experiment did not vary significantly in weight and no definite conclusion can be derived as to the effect of body size to bioaccumulation of I-131. (ELC)

Integrated testing strategies (ITS) for bioaccumulation: hierarchical scheme of chemistrydriven modules and definition of applicability domains

DEFF Research Database (Denmark)

Nendza, M.; Scheringer, M.; Strempel, S.

2011-01-01

The efficient assessment of the bioaccumulation potential of chemicals under REACH with integrated test strategies (ITS) requires multiple tools. Existing data have to be searched and information from chemical structures and physico-chemical properties need to be evaluated prior to considering to...

Fluoride bioaccumulation and toxic effects on the survival and behavior of the endangered white-clawed crayfish Austropotamobius pallipes (Lereboullet).

Science.gov (United States)

Aguirre-Sierra, Arantxa; Alonso, Alvaro; Camargo, Julio A

2013-08-01

Laboratory experiments were performed to examine the toxic effects of fluoride (F(-)) on the survival and behavior of white-clawed crayfish (Austropotamobius pallipes). Body fluoride contents (bioaccumulation) of test crayfish were also examined. No significant differences between male and female crayfish regarding mortality, escape (tail-flip) response, and fluoride bioaccumulation were detected. For mortality, 48-, 72-, 96-, 120-, 144-, 168-, and 192-h median lethal concentrations (LC50) were estimated to be 93.0, 55.3, 42.7, 36.5, 32.9, 30.6, and 28.9 mg F(-)/l, respectively. For the escape response, 48-, 72-, 96-, 120-, 144-, 168- and 192-h median effective concentrations (EC50) were estimated to be 18.4, 11.1, 8.6, 7.4, 6.7, 6.2 and 5.9 mg F(-)/l, respectively. Average food consumption in test crayfish tended to decrease with increasing water fluoride concentration with a 192-h lowest-observed effect concentration of 10.7 mg F(-)/l. These results indicate that the escape response was the most sensitive end point to fluoride toxicity followed by food consumption and mortality. Fluoride bioaccumulation in test crayfish increased with increasing water fluoride concentration and exposure time. The exoskeleton accumulated more fluoride than muscle. A comparison of the obtained results with previous data for other freshwater invertebrates shows that white-clawed crayfish are relatively tolerant to fluoride toxicity. We conclude that fluoride pollution in freshwater ecosystems should not be viewed as an important risk factor contributing to the catastrophic decrease of A. pallipes in many European countries. Our results indicate that fluoride bioaccumulation in A. pallipes might be used as a bioindicator of fluoride pollution in freshwater ecosystems where it is present.

Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

International Nuclear Information System (INIS)

Garaev, Valeriy; Pavlovica, Sanita; Vaivars, Guntars; Kleperis, Janis

2012-01-01

In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

Effect of nitrogen doping of graphene oxide on hydrogen and hydroxyl adsorption

Energy Technology Data Exchange (ETDEWEB)

Min, Byeong June; Jeong, Hae Kyung [Daegu University, Kyungsan (Korea, Republic of)

2014-05-15

We investigate how nitrogen-doping affects the hydrogen (H) and the hydroxyl (OH) adsorption on graphene oxide (GO) and on nitrogen-doped GO (NGO) via pseudopotential plane wave density functional calculations within the local spin density approximation. We find that the nitrogen doping brings about drastic changes in the hydrogen and the hydroxyl adsorption energetics, but its effects depend sensitively on the nitrogen configuration in NGO. The H and the OH adsorption energies are comparable only for pyrrolic NGO. In GO and quarternary NGO, the H adsorption energy is greater than the OH adsorption energy while the trend is reversed in pyridinic NGO. Also, the OH adsorption process is less affected by nitrogen-doping than the H adsorption is.

Pristine and thermally-rearranged gas separation membranes from novel o-hydroxyl-functionalized spirobifluorene-based polyimides

KAUST Repository

Ma, Xiaohua

2014-01-01

A novel o-hydroxyl-functionalized spirobifluorene-based diamine monomer, 2,2′-dihydroxyl-9,9′-spiro-bifluorene- 3,3′-diamine (HSBF), was successfully prepared by a universal synthetic method. Two o-hydroxyl-containing polyimides, denoted as 6FDA-HSBF and SPDA-HSBF, were synthesized and characterized. The BET surface areas of 6FDA-HSBF and SPDA-HSBF are 70 and 464 m2 g-1, respectively. To date, SPDA-HSBF exhibits the highest CO2 permeability (568 Barrer) among all hydroxyl-containing polyimides. The HSBF-based polyimides exhibited higher CO2/CH4 selectivity than their spirobifluorene (SBF) analogues (42 for 6FDA-HSBF vs. 27 for 6FDA-SBF) due to an increase in their diffusivity selectivity. Polybenzoxazole (PBO) membranes obtained from HSBF-based polyimide precursors by thermal rearrangement showed enhanced permeability but at the cost of significantly decreased selectivity.

Decomposition of water into highly combustible hydroxyl gas used in ...

African Journals Online (AJOL)

The method proposed involves the decomposition of water into highly combustible hydroxyl gas via electrolysis, which is used in internal combustion engines of electrical generators for electricity generation. The by-product obtained from combustion of this gas is water vapour and oxygen to replenish the atmosphere.

Modeling (137)Cs bioaccumulation in the salmon-resident killer whale food web of the Northeastern Pacific following the Fukushima Nuclear Accident.

Science.gov (United States)

Alava, Juan José; Gobas, Frank A P C

2016-02-15

To track the long term bioaccumulation of (137)Cs in marine organisms off the Pacific Northwest coast of Canada, we developed a time dependent bioaccumulation model for (137)Cs in a marine mammalian food web that included fish-eating resident killer whales. The model outcomes show that (137)Cs can be expected to gradually bioaccumulate in the food web over time as demonstrated by the increase of the apparent trophic magnification factor of (137)Cs, ranging from 0.76 after 1 month of exposure to 2.0 following 30 years of exposure. (137)Cs bioaccumulation is driven by relatively rapid dietary uptake rates, moderate depuration rates in lower trophic level organisms and slow elimination rates in high trophic level organisms. Model estimates of the (137)Cs activity in species of the food web, based on current measurements and forecasts of (137)Cs activities in oceanic waters and sediments off the Canadian Pacific Northwest, indicate that the long term (137)Cs activities in fish species including Pacific herring, wild Pacific salmon, sablefish and halibut will remain well below the current (137)Cs-Canada Action Level for consumption (1000 Bq/kg) following a nuclear emergency. Killer whales and Pacific salmon are expected to exhibit the largest long term (137)Cs activities and may be good sentinels for monitoring (137)Cs in the region. Assessment of the long term consequences of (137)Cs releases from the Fukushima aftermath should consider the extent of ecological magnification in addition to ocean dilution. Copyright © 2015 Elsevier B.V. All rights reserved.

Enhanced electrical properties in solution-processed InGaZnO thin-film transistors by viable hydroxyl group transfer process

Science.gov (United States)

Kim, Do-Kyung; Jeong, Hyeon-Seok; Kwon, Hyeok Bin; Kim, Young-Rae; Kang, Shin-Won; Bae, Jin-Hyuk

2018-05-01

We propose a simple hydroxyl group transfer method to improve the electrical characteristics of solution-processed amorphous InGaZnO (IGZO) thin-film transistors (TFTs). Tuned poly(dimethylsiloxane) elastomer, which has a hydroxyl group as a terminal chemical group, was adhered temporarily to an IGZO thin-film during the solidification step to transfer and supply sufficient hydroxyl groups to the IGZO thin-film. The transferred hydroxyl groups led to efficient hydrolysis and condensation reactions, resulting in a denser metal–oxygen–metal network being achieved in the IGZO thin-film compared to the conventional IGZO thin-film. In addition, it was confirmed that there was no morphological deformation, including to the film thickness and surface roughness. The hydroxyl group transferred IGZO based TFTs exhibited enhanced electrical properties (field-effect mobility of 2.21 cm2 V‑1 s‑1, and on/off current ratio of 106) compared to conventional IGZO TFTs (field-effect mobility of 0.73 cm2 V‑1 s‑1 and on/off current ratio of 105).

MERCURY IN EDIBLE WILD-GROWN MUSHROOMS FROM HISTORICAL MINING AREA – SLOVAKIA: BIOACCUMULATION AND RISK ASSESSMENT

Directory of Open Access Journals (Sweden)

Július Árvay

2015-02-01

Full Text Available In the present paper, we focused on assessment of the contamination levels of five species (n = 33 of edible wild mushrooms (Macrolepiota procera, Boletus reticulatus, Suillus grevillei, Russula xerampelina and Xerocomellus chrysenteron. We collected samples of above-ground parts of the macroscopic fungi species in historical mining and processing area surrounding Banská Bystrica (Central Slovakia in 2014. Within 2 m radius of the samples, we also took samples of underlying substrate. On the basis of the substrate, along with the monitored contaminant – mercury, we calculated bioaccumulation factors for individual species and their anatomical parts (cap and stipe. From the obtained results of the mercury content in the edible mushrooms, we then determined provisionally tolerable weekly intake (PTWI. The limit value for mercury (0.350 mg Hg kg-1 for an individual with average weight of 70 kg is defined by the World Health Organization (WHO. Our results suggest that despite the relatively low level of Hg in the underlying substrate, the species Macrolepiota procera (1.98 mg kg-1 ± 68.2 (0.41 - 3.20 mg kg-1 DW is characterized by extremely high bioaccumulation ability, as confirmed by the bioaccumulation factors (BAFc = 15.3; BAFs = 8.02. PTWI value was exceeded by almost 20%. In case of the other studied edible wild mushroom species, we did not record any increased risk of mercury intake by consumers. Generally it can be stated that consumption of wild mushrooms represents a relatively small but significant risk of negative impact on the consumer´s health.

Stability, electrochemical behaviors and electronic structures of iron hydroxyl-phosphate

Energy Technology Data Exchange (ETDEWEB)

Wang Zhongli; Sun Shaorui; Li Fan; Chen Ge [College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Chaoyang District, Beijing 100022 (China); Xia Dingguo, E-mail: dgxia@bjut.edu.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Chaoyang District, Beijing 100022 (China); Zhao Ting; Chu Wangsheng [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Science and Technology of China, Hefei 230026 (China); Wu Ziyu, E-mail: wuzy@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Science and Technology of China, Hefei 230026 (China)

2010-09-01

Iron hydroxyl-phosphate with a uniform spherical particle size of around 1 {mu}m, a compound of the type Fe{sub 2-y}{open_square}{sub y}(PO{sub 4})(OH){sub 3-3y}(H{sub 2}O){sub 3y-2} (where {open_square} represents a vacancy), has been synthesized by hydrothermal methods. The particles are composed of spheres of diameter <100 nm. The compound exhibits good electrochemical performance, with reversible capacities of around 150 mAh g{sup -1} and 120 mAh g{sup -1} at current densities of 170 mA g{sup -1} and 680 mA g{sup -1}, respectively. The stability of crystal structure of this material was studied by TGA and XRD which show that the material remains stable at least up to the temperature 200 deg. C. Investigation of the electronic structure of the iron hydroxyl-phosphate by GGA + U calculation has indicated that it has a better electronic conductivity than LiFePO{sub 4}.

Bioaccumulation of Aluminium in Hydromacrophytes in Polish Coastal Lakes

Directory of Open Access Journals (Sweden)

Senze Magdalena

2015-03-01

Full Text Available The research on aluminium content was conducted in water and on aquatic flora of Polish lakes in the central part of the coast. The study included the lakes Sarbsko, Choczewskie, Bia.e, K.odno, D.brze and Salino investigated in the summer of 2013. The examined lakes belong mainly to the direct basin of the Baltic Sea. Samples of aquatic plants and lake waters were collected. In the water samples pH and electrolytic conductivity were measured. The aluminium content was determined both in water and aquatic plants. Submerged hydromacrophyte studies included Myriophyllum alterniflorum L., Potamogeton perfoliatus L. and Ceratophyllum demersum L. Emergent hydromacrophyte studies included Phragmites australis (Cav. Trin. ex Steud., Juncus bulbosus L., Iris pseudacorus L., Eleocharis palustris (L. Roem. % Schult., Phalaris arundinacea L., Carex riparia Curt., Mentha aquatic L., Stratiotes aloides L., Alisma plantago-aquatica L., Glyceria maxima (Hartman Holmb., Sagittaria sagittifolia L., Scirpus lacustris L. and Typha angustifolia L. The purpose of this investigation was the determination of the aluminium content in submerged and emergent hydromacrophytes and also the definition of their bioaccumulative abilities. The average concentration of aluminium in water was 2.68 fęg Al dm.3. The average content of aluminium in plants was 2.8015 mg Al kg.1. The bioaccumulation factor ranged from BCF=19.74 to BCF=16619. On the basis of the analysis of the aluminium content in water and aquatic plants results show that both water and plants were characterized by a moderate level of aluminium. The recorded concentrations indicate a mid-range value and are much lower than those which are quoted for a variety of surface waters in various parts of the world.

Selenium speciation influences bioaccumulation in Limnodynastes peronii tadpoles

Energy Technology Data Exchange (ETDEWEB)

Lanctôt, C.M., E-mail: c.lanctot@griffith.edu.au [Central Queensland University, School of Medical and Applied Sciences, Gladstone, QLD 4680 (Australia); Australian Rivers Institute, School of Environment, Griffith University, Southport, QLD 4215 (Australia); Melvin, S.D., E-mail: s.melvin@griffith.edu.au [Australian Rivers Institute, School of Environment, Griffith University, Southport, QLD 4215 (Australia); Cresswell, T., E-mail: tom.cresswell@ansto.gov.au [Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

2017-06-15

Highlights: • Differences in SeIV and SeVI bioaccumulation and biodistribution were assessed. • Limnodynastes peronii tadpoles accumulated more selenite than selenate. • Selenium depuration kinetics was similar for both forms. • Tadpoles accumulated Se predominantly in the digestive and excretory organs. - Abstract: Despite being essential for animal health and fitness, Se has a relatively narrow range between deficiency and toxicity, and excess Se can cause a variety of adverse effects in aquatic organisms. Amphibians are particularly vulnerable to contaminants during larval aquatic life stage, because they can accumulate toxic ions through various routes including skin, gills, lungs and digestive tract. Few attempts have been made to understand the tissue-specific accumulation of trace elements, including the impacts of chemical speciation in developing amphibian larvae. We used radiolabelled {sup 75}Se to explore the biokinetics and tissue distributions of the two dominant forms occurring in surface waters, selenite (SeIV) and selenate (SeVI). Tadpoles of the native Australian frog Limnodynastes peronii were exposed to Se in both forms, and live-animal gamma spectroscopy was used to track accumulation and retention over time. Tissue biodistributions were also quantified at the end of the uptake and depuration phases. Results showed the bioconcentration of SeIV to be 3 times greater compared to SeVI, but rates of elimination were similar for both forms. This suggests a change of Se speciation within the organism prior to excretion. Depuration kinetics were best described by a one-phase exponential decay model, and tadpoles retained approximately 19% of the accumulated Se after 12 days of depuration in clean water. Selenium bioaccumulation was greatest in digestive and excretory organs, as well as the eye, which may directly relate to previously reported Se-induced impairments. Results demonstrate how the use of radiotracing techniques can significantly

Bioaccumulation of silver nanoparticles in rainbow trout (Oncorhynchus mykiss): Influence of concentration and salinity

International Nuclear Information System (INIS)

Salari Joo, Hamid; Kalbassi, Mohammad Reza; Yu, Il Je; Lee, Ji Hyun; Johari, Seyed Ali

2013-01-01

Highlights: •We studied influence of concentration and salinity on bioaccumulation of silver nanoparticles in rainbow trout (Oncorhynchus mykiss). •The Ag-NPs were characterized using standard methods. •The organisms were exposed to Ag-NPs in three different salinity concentrations, for 14 days in static renewal systems. •The bioaccumulation of Ag in the studied tissues was concentration-dependent in all the salinities and its order were liver > kidneys ≈ gills > white muscles respectively. -- Abstract: With the increasing use of silver nanoparticles (Ag-NPs), their entrance into aquatic ecosystems is inevitable. Thus, the present study simulated the potential fate, toxicity, and bioaccumulation of Ag-NPs released into aquatic systems with different salinities. The Ag-NPs were characterized using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), and UV–vis spectroscopy. Juvenile rainbow trout were exposed to Ag-NPs in three different salinity concentrations, including low (0.4 ppt), moderate (6 ± 0.3 ppt), and high (12 ± 0.2 ppt) salinity, for 14 days in static renewal systems. The nominal Ag-NP concentrations in the low salinity were 0.032, 0.1, 0.32, and 1 ppm, while the Ag-NP concentrations in the moderate and high salinity were 3.2, 10, 32, and 100 ppm. UV–vis spectroscopy was used during 48 h (re-dosing time) to evaluate the stability and possible changes in size of the Ag-NPs in the water. The results revealed that the λ max of the Ag-NPs remained stable (415–420 nm) at all concentrations in the low salinity with a reduction of absorbance between 380 and 550 nm. In contrast, the λ max quickly shifted to a longer wavelength and reduced absorbance in the moderate and higher salinity. The bioaccumulation of Ag in the studied tissues was concentration-dependent in all the salinities based on the following order

Bioaccumulation of silver nanoparticles in rainbow trout (Oncorhynchus mykiss): Influence of concentration and salinity

Energy Technology Data Exchange (ETDEWEB)

Salari Joo, Hamid, E-mail: h.salary1365@gmail.com [Department of Aquaculture, Marine Science Faculty, Tarbiat Modares University, Mazandaran, Noor (Iran, Islamic Republic of); Kalbassi, Mohammad Reza, E-mail: kalbassi_m@modares.ac.ir [Department of Aquaculture, Marine Science Faculty, Tarbiat Modares University, Mazandaran, Noor (Iran, Islamic Republic of); Yu, Il Je, E-mail: u1670916@chol.com [Institute of Nano-product Safety Research, Hoseo University, 165 Sechul-ri, Baebang-myun, Asan 336-795 (Korea, Republic of); Lee, Ji Hyun, E-mail: toxin@dreamwiz.com [Institute of Nano-product Safety Research, Hoseo University, Asan (Korea, Republic of); Johari, Seyed Ali, E-mail: a.johari@uok.ac.ir [Aquaculture Department, Natural Resources Faculty, University of Kurdistan, Kurdistan, Sanandaj (Iran, Islamic Republic of)

2013-09-15

Highlights: •We studied influence of concentration and salinity on bioaccumulation of silver nanoparticles in rainbow trout (Oncorhynchus mykiss). •The Ag-NPs were characterized using standard methods. •The organisms were exposed to Ag-NPs in three different salinity concentrations, for 14 days in static renewal systems. •The bioaccumulation of Ag in the studied tissues was concentration-dependent in all the salinities and its order were liver > kidneys ≈ gills > white muscles respectively. -- Abstract: With the increasing use of silver nanoparticles (Ag-NPs), their entrance into aquatic ecosystems is inevitable. Thus, the present study simulated the potential fate, toxicity, and bioaccumulation of Ag-NPs released into aquatic systems with different salinities. The Ag-NPs were characterized using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), and UV–vis spectroscopy. Juvenile rainbow trout were exposed to Ag-NPs in three different salinity concentrations, including low (0.4 ppt), moderate (6 ± 0.3 ppt), and high (12 ± 0.2 ppt) salinity, for 14 days in static renewal systems. The nominal Ag-NP concentrations in the low salinity were 0.032, 0.1, 0.32, and 1 ppm, while the Ag-NP concentrations in the moderate and high salinity were 3.2, 10, 32, and 100 ppm. UV–vis spectroscopy was used during 48 h (re-dosing time) to evaluate the stability and possible changes in size of the Ag-NPs in the water. The results revealed that the λ{sub max} of the Ag-NPs remained stable (415–420 nm) at all concentrations in the low salinity with a reduction of absorbance between 380 and 550 nm. In contrast, the λ{sub max} quickly shifted to a longer wavelength and reduced absorbance in the moderate and higher salinity. The bioaccumulation of Ag in the studied tissues was concentration-dependent in all the salinities based on the following

Seasonal PCB bioaccumulation in an arctic marine ecosystem: a model analysis incorporating lipid dynamics, food-web productivity and migration.

Science.gov (United States)

Laender, Frederik De; Oevelen, Dick Van; Frantzen, Sylvia; Middelburg, Jack J; Soetaert, Karline

2010-01-01

Primary production and species' lipid contents in Arctic ecosystems are notoriously seasonal. Additionally, seasonal migration patterns of fish may alter prey availability and thus diet. Taking the southern Barents Sea as a study region and PCBs as model contaminants, we examined to what extent each of these factors cause bioaccumulation in fish to change throughout the year. Data on physiology and standing stocks of multiple trophic levels were used to estimated season-specific carbon budgets and by inference also corresponding values for food ingestion and production of cod, capelin, and herring. When combining these values with Arctic lipid dynamics for bioaccumulation model parameter setting, we predicted bioaccumulation factors (BAFs) that were in good agreement with BAFs for cod and capelin observed between 1998 and 2008. BAFs in all fish were 10 times lower in summer than in spring and fall/winter and were mainly driven by lipid dynamics. Trophic magnification factors (TMFs: increase in BAF per unit increase in trophic level as derived from our carbon budgets) were highest for PCB 153 during spring (2.3-2.4) and lowest for PCB 52 in summer and fall/winter (1.5-1.6) and were driven by seasonal shifts in trophic level and lipid dynamics.

Influence of temperature on fluoride toxicity and bioaccumulation in the nonindigenous freshwater mollusk Dreissena polymorpha Pallas, 1769.

Science.gov (United States)

Del Piero, Stefania; Masiero, Luciano; Casellato, Sandra

2012-11-01

Fluoride toxicity and bioaccumulation tests (short- and long-term) were performed on the nonindigenous freshwater mollusk Dreissena polymorpha at two different temperatures: 17 ± 0.5°C and 22 ± 0.5°C. Concentrations that did not result in toxicity in short-term experiments (96 h) induced effects over a longer period (17 weeks), especially at the warmest temperature, highlighting the role of this parameter. Fluoride bioaccumulation increased linearly with increasing concentration and temperature, reaching 4,202 µg F(-)/g dry weight in soft tissues only after 48 h of exposure at 22°C at a concentration of 640 mg F(-)/L. Comparing tolerance to fluoride and bioaccumulation values of this species with those of other freshwater invertebrates, D. polymorpha was much more resistant and revealed its capacity to accumulate a great quantity of this xenobiotic substance. The results of the present study demonstrated that fluoride accumulation in the soft tissue of this animal was much higher (up to 1,409.6 µg F(-)/g dry wt) than that in its shell (up to 706.4 µg F(-)/g dry wt). If we consider this datum and the fact that D. polymorpha is widespread in many aquatic ecosystems around the world, representing a food source for many birds and other vertebrates, we must acknowledge the possibility that it can represent a serious danger in view of fluoride biomagnification in the aquatic environment. Copyright © 2012 SETAC.

Hydroxyl group as IR probe to detect the structure of ionic liquid-acetonitrile mixtures

Science.gov (United States)

Xu, Jing; Deng, Geng; Zhou, Yu; Ashraf, Hamad; Yu, Zhi-Wu

2018-06-01

Task-specific ionic liquids (ILs) are those with functional groups introduced in the cations or anions of ILs to bring about specific properties for various tasks. In this work, the hydrogen bonding interactions between a hydroxyl functionalized IL 1-(2-hydroxylethyl)-3-methylimidazolium tetrafluoroborate ([C2OHMIM][BF4]) and acetonitrile were investigated in detail by infrared spectroscopy, excess spectroscopy, two-dimensional correlation spectroscopy, combined with hydrogen nuclear magnetic resonance and density functional theory calculations (DFT). The hydroxyl group rather than C2sbnd H is found to be the main interaction site in the cation. And the ν(Osbnd H) is more sensitive than v(C-Hs) to the environment, which has been taken as an intrinsic probe to reflect the structural change of IL. Examining the region of ν(Osbnd H), by combining excess spectroscopy and DFT calculation, a number of species were identified in the mixtures. Other than the hydrogen bond between a cation and an anion, the hydroxyl group allows the formation of a hydrogen bond between two like-charged cations. The Osbnd H⋯O hydrogen bonding interactions in the hydroxyl-mediated cation-cation complexes are cooperative, while Osbnd H⋯F and C2sbnd H⋯F hydrogen bonding interactions in cation-anion complexes are anti-cooperative. These in-depth studies on the properties of the ionic liquid-acetonitrile mixtures may shed light on exploring their applications as mixed solvents and understanding the nature of doubly ionic hydrogen bonds.

Metal bioaccumulation by the freshwater alga Scenedesmus quadricauda

International Nuclear Information System (INIS)

Fargasova, A.

1997-01-01

Bioaccumulation of six metals (Cu 2+ , Cu + , Mo 6+ , Mn 2+ , V 5+ , Ni 2+ ) and their combinations by alga Scenedesmus quadricauda was determined by using radio nuclide X-ray fluorescence (RXFA). The metals were added into the cultivation medium in concentrations corresponding with EC 50 value for each metal. The obtained results indicate that Ni 2+ , Cu 2+ and Cu + were accumulated in high amounts (20%, 17.5% and 15.9%) the Mo 6+ ion ( 2+ , Ni, Mn, V; V→Ni, Mn; Mn→Ni, Cu 2+ , Cu + ; Cu + →Ni; Cu 2+ →Ni; Ni→Mn, V), enhancement (V→Cu + ; Cu 2+ →Mn; Cu + →V, Mn; Mn→V; Ni→Cu 2+ , Cu + ) and neutral effect (V→Mo; Cu 2+ →Mo; Cu + →Mo; Mn→Mo; Ni→Mo). (author)

The hydroxyl-functionalized magnetic particles for purification of glycan-binding proteins.

Science.gov (United States)

Sun, Xiuxuan; Yang, Ganglong; Sun, Shisheng; Quan, Rui; Dai, Weiwei; Li, Bin; Chen, Chao; Li, Zheng

2009-12-01

Glycan-protein interactions play important biological roles in biological processes. Although there are some methods such as glycan arrays that may elucidate recognition events between carbohydrates and protein as well as screen the important glycan-binding proteins, there is a lack of simple effectively separate method to purify them from complex samples. In proteomics studies, fractionation of samples can help to reduce their complexity and to enrich specific classes of proteins for subsequent downstream analyses. Herein, a rapid simple method for purification of glycan-binding proteins from proteomic samples was developed using hydroxyl-coated magnetic particles coupled with underivatized carbohydrate. Firstly, the epoxy-coated magnetic particles were further hydroxyl functionalized with 4-hydroxybenzhydrazide, then the carbohydrates were efficiently immobilized on hydroxyl functionalized surface of magnetic particles by formation of glycosidic bond with the hemiacetal group at the reducing end of the suitable carbohydrates via condensation. All conditions of this method were optimized. The magnetic particle-carbohydrate conjugates were used to purify the glycan-binding proteins from human serum. The fractionated glycan-binding protein population was displayed by SDS-PAGE. The result showed that the amount of 1 mg magnetic particles coupled with mannose in acetate buffer (pH 5.4) was 10 micromol. The fractionated glycan-binding protein population in human serum could be eluted from the magnetic particle-mannose conjugates by 0.1% SDS. The methodology could work together with the glycan microarrays for screening and purification of the important GBPs from complex protein samples.

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

International Nuclear Information System (INIS)

Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

2015-01-01

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t d,E ) and hydroxyl-radical oxidation half-lives (t ·OH,E ) in sunlit surface waters. The t d,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas t ·OH,E ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways

Influence of time, temperature, pH and inhibitors on bioaccumulation of radiocaesium - 137Cs by lichen Hypogymnia physodes

International Nuclear Information System (INIS)

Pipiska, M.; Kociova, M.; Hornik, M.; Augustin, J.; Lesny, J.

2005-01-01

Caesium bioaccumulation experiments were carried out at 4 to 60 o C using natural samples of the lichen Hypogymnia physodes. Thalli were incubated in 2.5 μmol.l -1 CsCl solutions labelled with 137 CsCl for up to 24 h at pH values from 2 to 10. Bioaccumulation of Cs + ions in the first phase of the lichen-CsCl solution interaction is rapid, neither pH, nor temperature dependent within the range 4 to 60 o C and observed also with the lichen biomass thermally inactivated at 60 o C or chemically by formaldehyde. The second phase of 137 Cs bioaccumulation is time, temperature and pH dependent and is inhibited by formaldehyde and thermal inactivation. The process at the initial concentration C 0 = 2.5 μmol.l -1 CsCl and 20 o C reached equilibrium within 12 hours. It can be described by the first order reaction kinetics equation: log [C t ] = 1.89 - 0.00153 t, R = -0.950. Maximal values of Cs-bioaccumulation were observed at 20 o C with minimum at 4 o C and 40 o C and at pH 4-5 with minimum at pH 2 and pH 6. Low caesium efflux values from lichen thalli by water and 0.1 mol.l -1 neutral salts at 20 o C and 24 h equilibrium were observed. Efflux characterized by distribution coefficients D = [Cs] solution /[Cs] biomass at biomass/solution ratio 1:25 (w/v, wet wt.), decreases in the order: Li+ - 78 · 10 -3 > NH 4 + = K + - 15 · 10 -3 > Cs + = Na + - 11 · 10 -3 . Low extractability of caesium from lichen by water and salt solutions can explain long persistent times of radiocaesium contamination sorbed by lichens, observed by many authors in caesium contaminated forest and mountain regions. Hypothesis of the role of the lichen secondary metabolites as caesium binders is discussed. (author)

Involvement of hydroxyl radicals in the release by ionizing radiation of a cell surface nuclease from Micorcoccus radiodurans

International Nuclear Information System (INIS)

Mitchel, R.E.J.

1975-01-01

The ionizing radiation-induced release of a surface exonuclease from Micrococcus radiodurans is to a large extent inhibited by the removal of water. Irradiation of a cell suspension saturated with O 2 (an effective aqueous electron and hydrogen atom scavenger) allows the same release as irradiation in the presence of N 2 . Ethanol (a good hydroxyl radical scavenger) protects the enzyme from release. These data suggest that hydroxyl radicals produced by the radiolysis of water are important releasing agents. Hydroxyl radicals produced by the ultraviolet decomposition of H 2 O 2 were effective in releasing the enzyme

Influence of lead-doped hydroponic medium on the adsorption/bioaccumulation processes of lead and phosphorus in roots and leaves of the aquatic macrophyte Eicchornia crassipes.

Science.gov (United States)

Espinoza-Quiñones, Fernando R; Módenes, Aparecido Nivaldo; de Oliveira, Ana Paula; Trigueros, Daniela Estelita Goes

2013-11-30

In this study, lead bioaccumulation by the living free-floating aquatic macrophyte Eicchornia crassipes in different hydroponic conditions with variations in phosphorus and lead concentrations was investigated. A set of growth experiments in hydroponic media doped with lead and phosphorus within a wide concentration range was performed for 32 days in a greenhouse. All experiments were carried out with periodic replacement of all nutrients and lead. The concentration of lead and nutrients in biomass was determined by synchrotron radiation-excited total reflection X-ray fluorescence. By increasing the lead concentration in the medium, a reduction in biomass growth was observed, but a higher phosphorus retention in roots and leaves was shown at lower lead concentrations. In addition, an increase in the amount of bioaccumulated lead and phosphorus in roots was observed for higher lead and phosphorus concentrations in the medium, reaching saturation values of 4 mg Pb g(-1) and 7 mg P g(-1), respectively. Four non-structural kinetic models were tested, to represent the bioaccumulation of lead and phosphorus in roots. Pseudo-second order and irreversible kinetic models described the lead bioaccumulation data well, however, an irreversible kinetic model better fitted phosphorus uptake in roots. Copyright © 2013 Elsevier Ltd. All rights reserved.

Species-dependent effects of biochar amendment on bioaccumulation of atrazine in earthworms

International Nuclear Information System (INIS)

Wang, Fang; Ji, Rong; Jiang, Zhongwei; Chen, Wei

2014-01-01

We observed that at a contamination level of 4.25 mg-atrazine/kg-soil, the biota–soil accumulation factor (BSAF) for the anecic M. guillelmi is approximately 5 times that for the epigeic E. foetida. This is attributable to the fact that bio-uptake by E. foetida is mainly through dermal absorption, whereas bio-uptake by M. guillelmi is largely affected by the gut processes, through which the physical grinding and surfactant-like materials facilitate the desorption of atrazine from soil. Strikingly, biochar amendment resulted in much greater reduction in BSAF for M. guillelmi than for E. foetida. At a biochar dose of 0.5% (wt:wt) the difference in BSAF between the two species became much smaller, and at a dose of 2% no statistical difference was observed. A likely explanation is that gut processes by M. guillelmi were much less effective in extracting atrazine from the biochar (the predominant phase wherein atrazine resided) than from soil particles. -- Highlights: • Greater bio-uptake was observed for anecic M. guillelmi than for epigeic E. foetida. • Gut processes of M. guillelmi can facilitate desorption of contaminants from soil. • Biochar amendment caused greater reduction in bioaccumulation for M. guillelmi. • Gut processes are much less effective in extracting atrazine from biochar. -- Amendment of contaminated soils/sediments with biochar is more effective for earthworm species with greater bioaccumulation capabilities

In situ exposures using caged organisms: a multi-compartment approach to detect aquatic toxicity and bioaccumulation

International Nuclear Information System (INIS)

Burton, G. Allen; Greenberg, Marc S.; Rowland, Carolyn D.; Irvine, Cameron A.; Lavoie, Daniel R.; Brooker, John A.; Moore, Laurie; Raymer, Delia F.N.; McWilliam, Ruth A.

2005-01-01

An in situ toxicity and bioaccumulation assessment approach is described to assess stressor exposure and effects in surface waters (low and high flow), the sediment-water interface, surficial sediments and pore waters (including groundwater upwellings). This approach can be used for exposing species, representing major functional and taxonomic groups. Pimephales promelas, Daphnia magna, Ceriodaphnia dubia, Hyalella azteca, Hyalella sp., Chironomus tentans, Lumbriculus variegatus, Hydra attenuatta, Hexagenia sp. and Baetis tibialis were successfully used to measure effects on survival, growth, feeding, and/or uptake. Stressors identified included chemical toxicants, suspended solids, photo-induced toxicity, indigenous predators, and flow. Responses varied between laboratory and in situ exposures in many cases and were attributed to differing exposure dynamics and sample-processing artifacts. These in situ exposure approaches provide unique assessment information that is complementary to traditional laboratory-based toxicity and bioaccumulation testing and reduce the uncertainties of extrapolating from the laboratory to field responses. - In situ exposures provide unique information that is complementary to traditional lab-based toxicity results

Methyl mercury bioaccumulation in long-finned eels, Anguilla dieffenbachii, from three rivers in Otago, New Zealand.

Science.gov (United States)

Redmayne, A C; Kim, J P; Closs, G P; Hunter, K A

2000-10-30

This research focuses on mercury (Hg) bioaccumulation in New Zealand long-tinned eels (Anguilla dieffenbachii) from the aquatic environment. Total Hg (HgT) and methyl mercury (MeHg) concentrations were determined in muscle tissue from eels living in three South Island rivers dominated respectively by urban, native bush and agricultural land-uses. Most of the Hg in eels was MeHg (> 84%) and the MeHg concentrations increased linearly with both length and eel age for a given river habitat. The annual growth rates for eels from the urban and agricultural streams were greater than for eels from the native bush stream. The average MeHg accumulation rate was significantly higher for the eels in the agricultural stream compared with either the urban or native bush catchments. These results are probably due to a combination of factors and further investigations in the lower food web are necessary to elucidate the exact mechanisms of MeHg bioaccumulation in these creatures.

The Haber Process Made Efficient by Hydroxylated Graphene

OpenAIRE

Chaban, Vitaly; Prezhdo, Oleg

2016-01-01

The Haber-Bosch process is the main industrial method for producing ammonia from diatomic nitrogen and hydrogen. Very demanding energetically, it uses an iron catalyst, and requires high temperature and pressure. Any improvement of the Haber process will have an extreme scientific and economic impact. We report a significant increase of ammonia production using hydroxylated graphene. Exploiting the polarity difference between N2/H2 and NH3, as well as the universal proton acceptor behavior of...

Review on the occurrence and profiles of polybrominated diphenyl ethers in the Philippines.

Science.gov (United States)

Mackintosh, Susan A; Wallace, Joshua S; Gross, Michael S; Navarro, Denise D; Pérez-Fuentetaja, Alicia; Alaee, Mehran; Montecastro, Doris; Aga, Diana S

2015-12-01

The environmental occurrence of polybrominated diphenyl ethers (PBDEs) has been a subject of concern for the past decade because they are persistent, bioaccumulative, and toxic. These compounds have been listed as persistent organic pollutants (POPs) by the Stockholm Convention and are expected to disperse in the global environment even after their use and production. While the occurrence of PBDEs has been well characterized in environmental and biological samples from North America, Europe, and some Asian countries (i.e. China, Japan, and Korea), there is a scarcity of available data in developing Asian countries, such as the Philippines. Examination of PBDE contamination in the Philippine environment is particularly important because regulations have only recently been implemented on the production and use of PBDEs in this country. Additionally, the Philippines receives e-waste from Western countries, which is becoming a major source of organic contaminants in the tropical Asian regions. Ultimately, the Philippines may be a hot spot for contributing to on-going global PBDE pollution due to long-range atmospheric transport. This paper presents a review of the available literature on PBDEs in both environmental and biological samples collected from the Philippines. It is also intended to provide an overview on the levels and congener profiles of PBDEs in samples from the Philippines and to compare these data with other Asian countries. New data are presented on PBDE occurrence and congener profiles in fish commonly consumed by Filipinos and in particulate matter samples collected in Metro Manila, the capital of the Philippines. Both studies contribute to the available knowledge of PBDEs in the Philippines. We aim to stress the importance of future studies in countries receiving e-wastes, such as the Philippines, and suggest what future directions might be taken to enhance the available data on the presence of PBDEs in the Philippine environment. Copyright © 2015

Selective bioaccumulation, biomagnification, and dissipation of hexachlorocyclohexane isomers in a freshwater food chain.

Science.gov (United States)

Di, Shanshan; Liu, Ruiquan; Chen, Li; Diao, Jinling; Zhou, Zhiqiang

2018-04-30

Hexachlorocyclohexane isomers (HCHs) are persistent organic pollutants (POPs), having potential risks to humans and ecosystem. This work evaluated the propensity of organisms to accumulate, eliminate, and transfer HCHs along the food chain (Tubifex tubifex and common carp (Cyprinus carpio)). The accumulation of HCHs from water by worms and carp was observed, and the concentrations increased with exposure time. After 8 days, the HCH concentrations in organisms remained stable. The accumulation factor (AF) values of HCHs in T. tubifex were higher than those in carp, indicating that the bioaccumulation abilities of HCHs in T. tubifex were higher than those in carp. The contaminated worms as a dietary source in the food chain led to significantly higher bioaccumulation in carp. The biomagnification factor (BMF) values of HCH isomers were all greater than 1. In the dissipation experiments, the elimination was fast and the half-lives were shorter than 2.5 days. The enantioselective accumulation and dissipation of α-HCH enantiomers were observed in worms and carp (food chain), and the enantiomeric differences should be taken into consideration in the study of contaminants risk assessment. The results on trophic transfer of HCHs in a freshwater food chain should be helpful for better understanding the fate, transport, and transfer of HCHs in freshwater environments.

4-Substituted-2-Methoxyphenol: Suitable Building Block to Prepare New Bioactive Natural-like Hydroxylated Biphenyls.

Science.gov (United States)

Dettori, Maria Antonietta; Fabbri, Davide; Pisano, Marina; Rozzo, Carla; Palmieri, Giuseppe; Dess, Alessandro; Dallocchio, Roberto; Delogu, Giovanna

2015-02-01

A small collection of eugenol- and curcumin-analog hydroxylated biphenyls was prepared by straightforward methods starting from natural 4-substituted-2-methoxyphenols and their antitumoral activity was evaluated in vitro . Two curcumin-biphenyl derivatives showed interesting growth inhibitory activities on different malignant melanoma cell lines with IC 50 ranging from 13 to 1 µM. Preliminary molecular modeling studies were carried out to evaluate conformations and dihedral angles suitable for antiproliferative activity in hydroxylated biphenyls bearing a side aliphatic chain.

Levels of dechloranes and polybrominated diphenyl ethers (PBDEs) in human serum from France.

Science.gov (United States)

Brasseur, Catherine; Pirard, Catherine; Scholl, Georges; De Pauw, Edwin; Viel, Jean-François; Shen, Li; Reiner, Eric J; Focant, Jean-François

2014-04-01

Human exposure to dechloranes has been evaluated in Western Europe (France) with the analysis of Dechlorane Plus (DP), Dechloranes (Dec) 602, 603 and 604, Chlordene Plus (CP) and Mirex in 48 serum samples collected between 2003 and 2005. While no production source has been identified in Europe until now, detection frequencies for all investigated dechloranes were high, except for Dec 604 which was below detection limit for all samples. The mean DP concentration was 1.40±1.40ng/g lipid weight (lw), lower than levels reported in serum from Chinese population, but higher than levels reported in Canadian human milk. To the best of our knowledge, this is the first time that ∑5dechlorane levels are reported for human serum. A specific pattern of contamination was found (Dec 603>DP>Mirex>Dec 602>CP) compared to other biota samples that have been analyzed from Europe, with Dec 603 as the most abundant dechlorane (mean level: 2.61±2.63ng/g lw). Dec 603 and CP levels were correlated with age and with levels of some bioaccumulative organochlorine pesticides (OCPs). These results indicate that bioaccumulation properties should be further investigated and taken in consideration when assessing human exposure to dechloranes. For comparison purposes, polybrominated diphenyl ether (PBDE) levels were also measured for BDE-47, -99, -100, -153 and -154 in the serum samples. As expected, BDE-47 and BDE-153 were the major congeners with mean levels of 2.06±1.80ng/g lw and 1.39±0.97ng/g lw, respectively. The mean ∑5PBDE levels (4.32±2.99ng/g lw) were in the range typical of Western Europe levels, but lower than the mean ∑5dechlorane levels (6.24±4.16ng/g lw). These results indicate that the attention to dechloranes should be continued if research indicates toxicological concerns. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stereoselective bioaccumulation of chiral PCB 91 in earthworm and its metabolomic and lipidomic responses.

Science.gov (United States)

He, Zeying; Wang, Yuehua; Zhang, Yanwei; Cheng, Haiyan; Liu, Xiaowei

2018-07-01

Stereoselective bioaccumulation, elimination, metabolomic and lipidomic responses of earthworm Eisenia fetida exposed to chiral polychlorinated biphenyl (PCB) 91 in an earthworm-soil system were investigated. Preferential bioaccumulation of (-)-PCB 91 and elimination of (+)-PCB 91 were observed following 50 and 500 μg/kg dwt exposures. Enantiomer fraction (EF) values decreased over time during the uptake and elimination periods. Metabolomics and lipidomics techniques based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) revealed significant changes in 108 metabolites after earthworms exposure to (+)-, (-)-, and (±)-PCB 91, compared to control groups. Forty two of these metabolites were identified as amino acids, nucleosides, fatty acids, dicarboxylic acids, vitamins or others. Lysophospholipids including six lysophosphatidylcholines (LPC), six lysophosphatidylethanolamine (LPE), eight lysophosphatidylinositol (LPI) and five lysophosphatidylserine (LPS) were also differentially expressed between exposure and control groups. Alterations in the levels of metabolites and lipids indicated stereoselective effects of chiral PCB 91 on earthworm amino acid, energy, and nucleotide metabolism, neurodevelopment and gene expression. Overall, the effects of (+)-PCB 91 were more pronounced than that of (-)- and (±)-PCB 91. Copyright © 2018 Elsevier Ltd. All rights reserved.

Thermal inactivation of enteric viruses and bioaccumulation of enteric foodborne viruses in live oysters (Crassostrea virginica)

Science.gov (United States)

Human enteric viruses are one of the main causative agents of shellfish associated outbreaks. In this study, the kinetics of viral bioaccumulation in live oysters and the heat stability of the most predominant enteric viruses were determined in both tissue culture and in oyster tissues. A human nor...

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

Energy Technology Data Exchange (ETDEWEB)

Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Siyu [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Ren, Honglei; Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

2015-09-15

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t{sub d,E}) and hydroxyl-radical oxidation half-lives (t{sub ·OH,E}) in sunlit surface waters. The t{sub d,E} values range from 0.56 min to 28.8 min at 45° N latitude, whereas t{sub ·OH,E} ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways.

Assessment of persistency and bioaccumulation in pesticide registration frameworks within the Organization for Economic Cooperation and Development.

NARCIS (Netherlands)

Montforts, Mark H M M

This article describes the results of a survey conducted in 2003 on methods used by different member countries within the Organization for Economic Cooperation and Development (OECD) to evaluate persistent and bioaccumulative pesticides. The objectives were to establish the differences in taking

Trends of metal bioaccumulation from 1990 to 2005 in Germany. Quality assurance in the sampling, analytics, and geostatistical evaluation; Trend der Schwermetall-Bioakkumulation 1990 bis 2005. Qualitaetssicherung bei Probenahme, Analytik, geostatistischer Auswertung

Energy Technology Data Exchange (ETDEWEB)

Schroeder, Winfried; Pesch, Roland [Hochschule Vechta (Germany). Lehrstuhl fuer Landschaftsoekologie; Matter, Yehia; Goeritz, Axel [LUFA Nord-West, Hameln (Germany). Inst. fuer Duengemittel und Saatgut; Genssler, Lutz [Landesamt fuer Natur, Umwelt und Verbraucherschutz Nordrhein-Westfalen, Recklinghausen (Germany); Dieffenbach-Fries, Helga [Umweltbundesamt (UBA), Langen (Germany). Fachgebiet II 5.4

2009-12-15

Since 1990, the UN ECE Heavy Metals in Mosses Surveys provide data inventories of the atmospheric heavy metal bioaccumulation across national boundaries in Europe. The results prove how air pollution control in Germany and in all of Europe affected the bioaccumulation of metals in those ecosystems that are not directly influenced by nearby emission sources. This article focuses on the assessment of spatio temporal patterns of the metal bioaccumulation in Germany since 1990. Furthermore, the spatial variance of the metal bioaccumulation is analysed with regard to sampling site-specific and regional land characteristics. Special focus hereby relies on the correlation of the metal concentration in mosses and in depositions. Hence, the moss surveys contribute to paragraph 12 of the German Federal Nature Conservation Act as well as to the 'Convention on Long-range Transboundary Air Pollution' (CLRTAP). (orig.)

Bioaccumulation of heavy metals both in wild and mariculture food chains in Daya Bay, South China

Science.gov (United States)

Qiu, Yao-Wen

2015-09-01

Bioaccumulation and trophic transfer of heavy metals both in the natural marine ecosystem (seawater, sediment, coral reef, phytoplankton, macrophyte, shrimp, crab, shellfish, planktivorous and carnivorous fish) and in the mariculture ecosystem (compound feed, trash fish, farmed pompano and snapper) were studied at Daya Bay, a typical subtropical bay in Southern China. The levels of Cu, Zn, Pb and Cd in sediment were 11.7, 10.2, 53.8 and 2.8 times than those in coral reef, respectively. Pb and Zn levels were markedly higher in phytoplankton than in macrophyte, probably caused by the larger specific surface area in phytoplankton. The highest levels of Zn (98.1), Pb (1.87) and Cd (5.11 μg g-1 dw) in wild organisms were all found in clam (Veremolpa scabra), indicating that these metals were apt to bioaccumulate in shellfish. The average concentrations of Cu, Zn, Pb and Cd in wild fish were 3.7, 2.1, 0.4 and 22.2 times than those in farmed fish, confirming the "growth dilution" hypothesis in farmed fish. Heavy metal bioconcentration factors (BCFs) in algae, bioaccumulation factors (BAFs) in wild species and transfer factors (TFs) in organism were calculated and discussed. The results suggested that biologically essential Cu and Zn were easier to accumulate in fish than non-essential Cd. Concentrations of Cu, Zn and Cd were several times higher in wild fish than in farmed fish whereas the opposite was observed for Pb. This metal also showed the highest transfer factor from food, which means that special attention must be given to fish feed production in relation to metal contamination.

Measurement and modeling of diel variability of polybrominated diphenyl ethers and chlordanes in air.

Science.gov (United States)

Moeckel, Claudia; Macleod, Matthew; Hungerbühler, Konrad; Jones, Kevin C

2008-05-01

Short-term variability of concentrations of polybrominated diphenyl ethers (PBDEs) and chlordanes in air at a semirural site in England over a 5 day period is reported. Four-hour air samples were collected during a period dominated by a high pressure system that produced stable diel (24-h) patterns of meteorological conditions such as temperature and atmospheric boundary layer height. PBDE and chlordane concentrations showed clear diel variability with concentrations in the afternoon and evening being 1.9 - 2.7 times higher than in the early morning. The measurements are interpreted using a multimedia mass balance model parametrized with forcing functions representing local temperature, atmospheric boundary layer height, wind speed and hydroxyl radical concentrations. Model results indicate that reversible, temperature-controlled air-surface exchange is the primary driver of the diel concentration pattern observed for chlordanes and PBDE 28. For higher brominated PBDE congeners (47, 99 and 100), the effect of variable atmospheric mixing height in combination with irreversible deposition on aerosol particles is dominant and explains the diel patterns almost entirely. Higher concentrations of chlordanes and PBDEs in air observed at the end of the study period could be related to likely source areas using back trajectory analysis. This is the first study to clearly document diel variability in concentrations of PBDEs in air over a period of several days. Our model analysis indicates that high daytime and low nighttime concentrations of semivolatile organic chemicals can arise from different underlying driving processes, and are not necessarily evidence of reversible air-surface exchange on a 24-h time scale.

Effects of partial hydrogenation, epoxidation, and hydroxylation on the fuel properties of fatty acid methyl esters

Energy Technology Data Exchange (ETDEWEB)

Wadumesthrige, Kapila; Salley, Steven O.; Ng, K.Y. Simon [Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, MI 48202 (United States)

2009-10-15

The properties of biodiesel depend on the chemical structure of individual fatty acid methyl esters (FAME). In this work the chemical structure of fatty acid chains was modified by catalytic hydrogenation, epoxidation and hydroxylation under controlled conditions. Hydrolysis of ester functionality or oxidation of fatty acid chain was not observed during these reactions. The properties of hydrogenated FAME strongly depend on the hydrogenation time. The total saturated fatty acid (SFA) percentage increased from 29.3% to 76.2% after 2 h of hydrogenation. This hydrogenated FAME showed higher oxidation stability and higher cetane number but poor cold flow properties. Formation of trans FAME was observed during hydrogenation. Both hydroxylation and epoxidation resulted in a decrease of unsaturated fatty acid methyl ester (UFA) fraction. The percentages of total unsaturated FAME decreased 39% in the epoxidation reaction and 44% in the hydroxylation reaction. The addition of hydroxyl groups to the unsaturated regions of the fatty acid chain yields biodiesel with better cold flow properties, increased lubricity and slightly increased oxidative stability. However, epoxy FAME shows some interesting properties such as higher oxidation stability, higher cetane number and acceptable cold flow properties, which met the limits of ASTM D6751 biodiesel specifications. (author)

Monolayer arrangement of fatty hydroxystearic acids on graphite: Influence of hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Medina, S. [Laboratorio de Rayos-X, Centro de Investigación Tecnología e Innovación, de la Universidad de Sevilla (CITIUS), Universidad de Sevilla, Avenida Reina Mercedes, 4B. 41012, Sevilla (Spain); Benítez, J.J.; Castro, M.A. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain); Cerrillos, C. [Servicio de Microscopía, Centro de Investigación Tecnología e Innovación, de la Universidad de Sevilla (CITIUS), Universidad de Sevilla, Avenida Reina Mercedes, 4B. 41012, Sevilla (Spain); Millán, C. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain); Alba, M.D., E-mail: alba@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain)

2013-07-31

Previous studies have indicated that long-chain linear carboxylic acids form commensurate packed crystalline monolayers on graphite even at temperatures above their melting point. This study examines the effect on the monolayer formation and structure of adding one or more secondary hydroxyl, functional groups to the stearic acid skeleton (namely, 12-hydroxystearic and 9,10-dihydroxystearic acid). Moreover, a comparative study of the monolayer formation on recompressed and monocrystalline graphite has been performed through X-ray diffraction (XRD) and Scanning Tunneling Microscopy (STM), respectively. The Differential Scanning Calorimetry (DSC) and XRD data were used to confirm the formation of solid monolayers and XRD data have provided a detailed structural analysis of the monolayers in good correspondence with obtained STM images. DSC and XRD have demonstrated that, in stearic acid and 12-hydroxystearic acid adsorbed onto graphite, the monolayer melted at a higher temperature than the bulk form of the carboxylic acid. However, no difference was observed between the melting point of the monolayer and the bulk form for 9,10-dihydroxystearic acid adsorbed onto graphite. STM results indicated that all acids on the surface have a rectangular p2 monolayer structure, whose lattice parameters were uniaxially commensurate on the a-axis. This structure does not correlate with the initial structure of the pure compounds after dissolving, but it is conditioned to favor a) hydrogen bond formation between the carboxylic groups and b) formation of hydrogen bonds between secondary hydroxyl groups, if spatially permissible. Therefore, the presence of hydroxyl functional groups affects the secondary structure and behavior of stearic acid in the monolayer. - Highlights: • Hydroxyl functional groups affect structure and behavior of acids in the monolayer. • Acids on the surface have a rectangular p2 monolayer structure. • Lattice parameters of acids are uniaxially

Investigating the Source of Water and/or Hydroxyl on Asteroid (16) Psyche

Science.gov (United States)

Takir, D.; Reddy, V.; Sanchez, J. A.; Shepard, M. K.; Emery, J. P.

2017-12-01

Asteroid (16) Psyche will be visited by the Psyche mission, which was selected by NASA and will be launched in 2022 as the 14th Discovery mission. Psyche is thought to be one of the most massive exposed metallic core in the asteroid belt. The high radar albedos, thermal inertia, and density of Psyche revealed that this asteroid is composed of almost entirely of Fe-Ni metal. Psyche is also characterized by moderately red spectra and the presence of weak features (attributed to silicates) in the visible and near-infrared (NIR) region (0.3-2.5 µm). Recent NIR observations also showed rotational spectral variations indicating a possible change in the metal/silicate ratio on the surface of this asteroid. Additionally, we observed Psyche in the 3-µm spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 µm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). Our observations revealed that Psyche exhibits a 3-µm feature, more likely attributed to water- and/or hydroxyl molecules. While the source of water and/or hydroxyl on Psyche remains unclear, we proposed a few possible mechanisms for their formation: (1) the water/hydroxyl-rich materials detected on Psyche might have been delivered to its surface by carbonaceous impactors (like on Vesta), (2) Psyche may not be entirely exposed metallic, instead, its surface has a core-mantle boundary of a differentiated body that was disrupted by impacts (e.g., Pallasite-like), or (3) the water/hydroxyl-rich materials detected on Psyche is produced by Solar wind implantation (like on the Moon). In this talk we will discuss these three possible mechanisms and hypotheses and how they can be tested prior to the launch of the Psyche spacecraft using predictive laboratory measurements and modeling, and during the spacecraft encounter with the asteroid using the mission main instruments that will include the multispectral imagers, the gamma-ray and neutron spectrometer, and the dual

Urocanic acid isomers are good hydroxyl radical scavengers: a comparative study with structural analogues and with uric acid

NARCIS (Netherlands)

Kammeyer, A.; Eggelte, T. A.; Bos, J. D.; Teunissen, M. B.

1999-01-01

UV-exposure of the epidermis leads to the isomerisation of trans-UCA into cis-UCA as well as to the generation of hydroxyl radicals. This study shows by means of the deoxyribose degradation test that UCA isomers are more powerful hydroxyl radical scavengers than the other 4-(5-)substituted imidazole

In Situ Evaluation of Crop Productivity and Bioaccumulation of Heavy Metals in Paddy Soils after Remediation of Metal-Contaminated Soils.

Science.gov (United States)

Kim, Shin Woong; Chae, Yooeun; Moon, Jongmin; Kim, Dokyung; Cui, Rongxue; An, Gyeonghyeon; Jeong, Seung-Woo; An, Youn-Joo

2017-02-15

Soils contaminated with heavy metals have been reused for agricultural, building, and industrial uses following remediation. This study assesses plant growth and bioaccumulation of heavy metals following remediation of industrially contaminated soil. The soil was collected from a field site near a nonferrous smelter and was subjected to laboratory- and field-scale studies. Soil from the contaminated site was remediated by washing with acid or mixed with soil taken from a distant uncontaminated site. The activities of various soil exoenzymes, the rate of plant growth, and the bioaccumulations of six heavy metals were measured to assess the efficacy of these bioremediation techniques. Growth of rice (Oryza sativa) was unaffected in acid-washed soil or the amended soil compared to untreated soil from the contaminated site. The levels of heavy metals in the rice kernels remained within safe limits in treated and untreated soils. Rice, sorghum (Sorghum bicolor), and wheat (Triticum aestivum) cultivated in the same soils in the laboratory showed similar growth rates. Soil exoenzyme activities and crop productivity were not affected by soil treatment in field experiments. In conclusion, treatment of industrially contaminated soil by acid washing or amendment did not adversely affect plant productivity or lead to increased bioaccumulation of heavy metals in rice.

Trace metals bioaccumulation potentials of three indigenous grasses grown on polluted soils collected around mining areas in Pretoria, South Africa

International Nuclear Information System (INIS)

Lion, G. N.; Olowoyo, J. O.; Modise, T. A.

2016-01-01

The rapid increase in the number of industries may have increased the levels of trace metals in the soil. Phyto remediation of these polluted soils using indigenous grasses is now considered an alternative method in re mediating these polluted soils. The present study investigated and compared the ability of three indigenous grasses as bioaccumulators of trace metals from polluted soils. Seeds of these grasses were introduced into pots containing polluted soil samples after the addition of organic manure. The seeds of the grasses were allowed to germinate and grow to maturity before harvesting. The harvested grasses were later separated into shoots and roots and the trace metal contents were determined using ICP –MS. From all the grasses, the concentrations of trace metals in the roots were more than those recorded in the shoot with a significant difference (P Themeda trianda > Cynodon dactylon. The study concluded that the three grasses used were all able to bioaccumulate trace metals in a similar proportion from the polluted soils. However, since livestock feed on these grasses, they should not be allowed to feed on the grasses used in this study especially when harvested from a polluted soil due to their bioaccumulative potentials. (au)

Hydroxyl radical-modified fibrinogen as a marker of thrombosis: the role of iron.

Science.gov (United States)

Lipinski, B; Pretorius, E

2012-07-01

Excessive free iron in blood and in organ tissues (so called iron overload) has been observed in degenerative diseases such as atherosclerosis, cancer, neurological, and certain autoimmune diseases, in which fibrin-like deposits are also found. Although most of the body iron is bound to hemoglobin and myoglobin in a divalent ferrous form, a certain amount of iron exists in blood as a trivalent (ferric) ion. This particular chemical state of iron has been shown to be toxic to the human body when not controlled by endogenous and/or dietary chelating agents. Experiments described in this paper show for the first time that ferric ions (Fe(3+)) can generate hydroxyl radicals without participation of any redox agent, thus making it a special case of the Fenton reaction. Ferric chloride was also demonstrated to induce aggregation of purified fibrinogen at the same molar concentrations that were used for the generation of hydroxyl radicals. Iron-aggregated fibrinogen, by contrast to native molecule, could not be dissociated into polypeptide subunit chains as shown in a polyacrylamide gel electrophoresis. The mechanism of this phenomenon is very likely based on hydroxyl radical-induced modification of fibrinogen tertiary structure with the formation of insoluble aggregates resistant to enzymatic and chemical degradations. Soluble modified fibrinogen species can be determined in blood of thrombotic patients by the reaction with protamine sulfate and/or by scanning electron microscopy. In view of these findings, it is postulated that iron-induced alterations in fibrinogen structure is involved in pathogenesis of certain degenerative diseases associated with iron overload and persistent thrombosis. It is concluded that the detection of hydroxyl radical-modified fibrinogen may be utilized as a marker of a thrombotic condition in human subjects.

Fabrication and characterisation of fluidic based memristor sensor for liquid with hydroxyl group

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Nor Shahanim Mohamad Hadis

2017-06-01

Full Text Available Two types of memristor sensor were fabricated using two different TiO2 deposition methods of sputtering and sol-gel spin coating. The surface morphology of the sensors and the behaviour of the sensors were analysed by using scanning electron microscopy with energy dispersive x-ray system and I-V characterisation system respectively. The sensors were applied with liquid with hydroxyl group to check the capability of this sensor in sensing different concentration of hydroxyl ion inside the liquid. For that purpose, d-glucose liquid with four concentrations of 10mM, 20mM, 30mM and 40mM were chosen. The liquids dispensed onto the TiO2 surface to act as sensing material. The TiO2 surface was initially covered with polydimethylsiloxane to control the liquid. The sensing capability of the sensors was determined via the current-voltage measurement and off-on resistance ratio. The sensitivity of the sensors was analysed from the off-on resistance ratio analysis. Type II memristor sensor which was fabricated using sol-gel spin coating technique recorded high sensitivity of 120.65 (mM−1, while Type I sensor fabricated using the sputtering technique recorded low sensitivity of 0.035 (mM−1. However, SEM-EDX image illustrated that the sputtering technique produced more uniform TiO2 thin film than sol-gel spin coating technique with larger atomic number of oxygen through the sol-gel spin coating technique. This indicates Type II sensor that has large number of oxygen atom produced more reaction with hydroxyl ion inside the liquid. While, Type I sensor produced less reaction compared with Type II and thus produced smaller off-on resistance ratio. Keywords: Fluidic based memristor, Hydroxyl ion, I-V characteristics, Off-on resistance ratio

Diffusion of hydroxyl ions from calcium hydroxide and Aloe vera pastes.

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Batista, Victor Eduardo de Souza; Olian, Douglas Dáquila; Mori, Graziela Garrido

2014-01-01

This study evaluated the diffusion through the dentinal tubules of hydroxyl ions from different calcium hydroxide (CH) pastes containing Aloe vera. Sixty single-rooted bovine teeth were used. The tooth crowns were removed, the root canals were instrumented and the specimens were assigned to 4 groups (n=15) according to the intracanal medication: Group CH/S - CH powder and saline paste; Group CH/P - CH powder and propylene glycol paste; Group CH/A - calcium hydroxide powder and Aloe vera gel paste; Group CH/A/P - CH powder, Aloe vera powder and propylene glycol paste. After placement of the root canal dressings, the teeth were sealed coronally and apically with a two-step epoxy adhesive. The teeth were placed in identified flasks containing deionized water and stored in an oven with 100% humidity at 37 °C. After 3 h, 24 h, 72 h, 7 days, 15 days and 30 days, the deionized water in the flasks was collected and its pH was measured by a pH meter. The obtained data were subjected to statistical analysis at a significance level of 5%. The results demonstrated that all pastes provided diffusion of hydroxyl ions through the dentinal tubules. The combination of Aloe vera and CH (group CH/A) provided a constant release of calcium ions. Group CH/A/P showed the highest pH at 24 and 72 h. In conclusion, the experimental pastes containing Aloe vera were able to enable the diffusion of hydroxyl ions through the dentinal tubules.

Mechanism of the N-Hydroxylation of Primary and Secondary Amines by Cytochrome P450

DEFF Research Database (Denmark)

Seger, Signe T.; Rydberg, Patrik; Olsen, Lars

2015-01-01

Cytochrome P450 enzymes (CYPs) metabolize alkyl- and arylamines, generating several different products. For the primary and secondary amines, some of these reactions result in hydroxylated amines, which may be toxic. Thus, when designing new drugs containing amine groups, it is important to be able...... to predict if a given compound will be a substrate for CYPs, in order to avoid toxic metabolites, and hence to understand the mechanism that is utilized by CYPs. Two possible mechanisms, for the N-hydroxylation of primary and secondary amines mediated by CYPs, are studied by density functional theory (DFT...

Activity of Oligoresveratrols from Stem Bark of Hopea mengarawan (Dipterocarpaceae as Hydroxyl Radical Scavenger

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SRI ATUN

2006-06-01

Full Text Available Four oligoresveratrols ranging from dimer to tetramer, isolated from stem bark of Hopea mengarawan (Dipterocarpaceae plants were tested for their activity as hydroxyl radical scavenger. The activity of these compounds was evaluated against the 2-deoxyribose degradation induced by the hydroxyl radical generated via a Fenton-type reaction. Result showed that balanocarpol, heimiol A, vaticanol G, and vaticanol B had IC50 3.83; 15.44; 2.01; and 4.71 µM, respectively. These results suggest that oligoresveratrols from stem bark of H. mengarawan maybe useful as potential sources of natural antioxidants.

Determining the local origin of hydroxyl radical generation during phacoemulsification.

Science.gov (United States)

Aust, Steven D; Terry, Scott; Hebdon, Thomas; Gunderson, Broc; Terry, Michael; Dimalanta, Ramon

2011-06-01

To determine the local origin of hydroxyl radicals during phacoemulsification using an ultrasonic phacoemulsification device that includes longitudinal and torsional modalities. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. Experimental study. Experiments were conducted using the Infiniti Vision System and Ozil handpiece. Hydroxyl radical concentrations during longitudinal and torsional phacoemulsification were quantitated as malondialdehyde (MDA) determined spectrophotometrically using the deoxyribose assay. The difference between the total concentration found in the aspirated solution at steady-state concentrations and the pre-aspirate levels deductively determined the concentration of MDA formed along the interior of the sonicating tip. The time to reach 50% of steady state as a function of reaction vessel volume was determined. The mean maximum for torsional ultrasound at 100% amplitude was 7.70 nM ± 0.38 (SD), 91.1% of which was generated outside the tip. During longitudinal ultrasound at 100% power, MDA concentration in the aspirated solution was 29.5 ± 0.3 nM, 71.6% of which was generated outside the tip. The time (seconds) to reach 50% of maximum for longitudinal ultrasound using 5 mL, 10 mL, and 20 mL reaction vessels was 12.6 ± 1.5, 21.0 ± 1.5, and 25.3 ± 3.4, respectively. Although a significantly greater proportion of the hydroxyl radicals generated during ultrasound modality were formed outside the phaco tip (91.1% torsional; 71.6% longitudinal), torsional ultrasound generated only about one-fourth the amount of MDA as longitudinal ultrasound in total and about one-third that generated outside the tip (7.02 nM versus 21.1 nM). No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Methemoglobinemia Hemotoxicity of Some Antimalarial 8-Aminoquinoline Analogues and Their Hydroxylated Derivatives: Density Functional Theory Computation of Ionization Potentials.

Science.gov (United States)

Ding, Yuanqing; Liu, Haining; Tekwani, Babu L; Nanayakkara, N P Dhammika; Khan, Ikhlas A; Walker, Larry A; Doerksen, Robert J

2016-07-18

The administration of primaquine (PQ), an essential drug for the treatment and radical cure of malaria, can lead to methemoglobin formation and life-threatening hemolysis for glucose-6-phosphate dehydrogenase deficient patients. The ionization potential (IP, a quantitative measure of the ability to lose an electron) of the metabolites generated by antimalarial 8-aminoquinoline (8-AQ) drugs like PQ has been believed to be correlated in part to this methemoglobinemia hemotoxicity: the lower the IP of an 8-AQ derivative, the higher the concentration of methemoglobin generated. In this work, demethoxylated primaquine (AQ02) was employed as a model, by intensive computation at the B3LYP-SCRF(PCM)/6-311++G**//B3LYP/6-31G** level in water, to study the effects of hydroxylation at various positions on the ionization potential. Compared to the parent AQ02, the IPs of AQ02's metabolites hydroxylated at N1', C5, and C7 were lower by 61, 30, and 19 kJ/mol, respectively, while differences in the IP relative to PQ were small for hydroxylation at all other positions. The C6 position, at which the IP of the hydroxylated metabolite was greater than that of AQ02, by 2 kJ/mol, was found to be unique. Several literature and proposed 8-AQ analogues were studied to evaluate substituent effects on their potential to generate methemoglobin, with the finding that hydroxylations at N1' and C5 contribute the most to the potential hemotoxicity of PQ-based antimalarials, whereas hydroxylation at C7 has little effect. Phenoxylation at C5 in PQ-based 8-AQs can block the hydroxylation at C5 and reduce the potential for methemoglobin generation, while -CF3 and chlorines attached to the phenolic ring can further reduce the risk. The H-shift at N1' during the cationization of hydroxylated metabolites of 8-AQs sharply decreased their IPs, but this effect can be significantly reduced by the introduction of an electron-withdrawing group to the quinoline core. The results and this approach may be

Interactions between zooplankton and crude oil: toxic effects and bioaccumulation of polycyclic aromatic hydrocarbons.

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Rodrigo Almeda

Full Text Available We conducted ship-, shore- and laboratory-based crude oil exposure experiments to investigate (1 the effects of crude oil (Louisiana light sweet oil on survival and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs in mesozooplankton communities, (2 the lethal effects of dispersant (Corexit 9500A and dispersant-treated oil on mesozooplankton, (3 the influence of UVB radiation/sunlight exposure on the toxicity of dispersed crude oil to mesozooplankton, and (4 the role of marine protozoans on the sublethal effects of crude oil and in the bioaccumulation of PAHs in the copepod Acartia tonsa. Mortality of mesozooplankton increased with increasing oil concentration following a sigmoid model with a median lethal concentration of 32.4 µl L(-1 in 16 h. At the ratio of dispersant to oil commonly used in the treatment of oil spills (i.e. 1∶20, dispersant (0.25 µl L(-1 and dispersant-treated oil were 2.3 and 3.4 times more toxic, respectively, than crude oil alone (5 µl L(-1 to mesozooplankton. UVB radiation increased the lethal effects of dispersed crude oil in mesozooplankton communities by 35%. We observed selective bioaccumulation of five PAHs, fluoranthene, phenanthrene, pyrene, chrysene and benzo[b]fluoranthene in both mesozooplankton communities and in the copepod A. tonsa. The presence of the protozoan Oxyrrhis marina reduced sublethal effects of oil on A. tonsa and was related to lower accumulations of PAHs in tissues and fecal pellets, suggesting that protozoa may be important in mitigating the harmful effects of crude oil exposure in copepods and the transfer of PAHs to higher trophic levels. Overall, our results indicate that the negative impact of oil spills on mesozooplankton may be increased by the use of chemical dispersant and UV radiation, but attenuated by crude oil-microbial food webs interactions, and that both mesozooplankton and protozoans may play an important role in fate of PAHs in marine environments.

Interactions between Zooplankton and Crude Oil: Toxic Effects and Bioaccumulation of Polycyclic Aromatic Hydrocarbons

Science.gov (United States)

Almeda, Rodrigo; Wambaugh, Zoe; Wang, Zucheng; Hyatt, Cammie; Liu, Zhanfei; Buskey, Edward J.

2013-01-01

We conducted ship-, shore- and laboratory-based crude oil exposure experiments to investigate (1) the effects of crude oil (Louisiana light sweet oil) on survival and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in mesozooplankton communities, (2) the lethal effects of dispersant (Corexit 9500A) and dispersant-treated oil on mesozooplankton, (3) the influence of UVB radiation/sunlight exposure on the toxicity of dispersed crude oil to mesozooplankton, and (4) the role of marine protozoans on the sublethal effects of crude oil and in the bioaccumulation of PAHs in the copepod Acartia tonsa. Mortality of mesozooplankton increased with increasing oil concentration following a sigmoid model with a median lethal concentration of 32.4 µl L−1 in 16 h. At the ratio of dispersant to oil commonly used in the treatment of oil spills (i.e. 1∶20), dispersant (0.25 µl L−1) and dispersant- treated oil were 2.3 and 3.4 times more toxic, respectively, than crude oil alone (5 µl L−1) to mesozooplankton. UVB radiation increased the lethal effects of dispersed crude oil in mesozooplankton communities by 35%. We observed selective bioaccumulation of five PAHs, fluoranthene, phenanthrene, pyrene, chrysene and benzo[b]fluoranthene in both mesozooplankton communities and in the copepod A. tonsa. The presence of the protozoan Oxyrrhis marina reduced sublethal effects of oil on A. tonsa and was related to lower accumulations of PAHs in tissues and fecal pellets, suggesting that protozoa may be important in mitigating the harmful effects of crude oil exposure in copepods and the transfer of PAHs to higher trophic levels. Overall, our results indicate that the negative impact of oil spills on mesozooplankton may be increased by the use of chemical dispersant and UV radiation, but attenuated by crude oil-microbial food webs interactions, and that both mesozooplankton and protozoans may play an important role in fate of PAHs in marine environments. PMID:23840628

Effect of Bulky and Hydroxyl Groups on Gas Separation Performance of Polyimide Membranes.

Science.gov (United States)

Lee, Bo Mi; Kim, Deuk Ju; Nam, Sang Yong

2015-03-01

A series of polyimides were synthesized by a polycondensation reaction using various aromatic dianhydrides and diamines containing bulky cardo and hydroxyl groups. The imidization and chemical structure of the polyimides were confirmed by NMR and FT-IR. The thermal and gas properties of the polyimides were measured by time-lag, XRD, TGA, and DSC studies. The polyimides showed excellent solubility in common organic solvents and high thermal stability. The CO2 selectivity of HPI membrane was higher than traditional polyimides. In particular, the incorporation of hydroxyl groups improved the CO2 permeability of the polyimide due to increased carbon dioxide solubility. The HPI was thermally converted to polybenzoxazole (PBO) at 450 °C.

Effects of feeding and organism loading rate on PCB accumulation by Lumbriculus variegatus in sediment bioaccumulation testing

Science.gov (United States)

Sediment bioaccumulation test methods published by USEPA and ASTM in 2000 specify that the Lumbriculus variegatus, a freshwater oligochaete, should not be fed during the 28-day exposure and recommends an organism loading rate of total organic carbon in sediment to organism dry we...

Mercury bioaccumulation in bats reflects dietary connectivity to aquatic food webs.

Science.gov (United States)

Becker, Daniel J; Chumchal, Matthew M; Broders, Hugh G; Korstian, Jennifer M; Clare, Elizabeth L; Rainwater, Thomas R; Platt, Steven G; Simmons, Nancy B; Fenton, M Brock

2018-02-01

Mercury (Hg) is a persistent and widespread heavy metal with neurotoxic effects in wildlife. While bioaccumulation of Hg has historically been studied in aquatic food webs, terrestrial consumers can become contaminated with Hg when they feed on aquatic organisms (e.g., emergent aquatic insects, fish, and amphibians). However, the extent to which dietary connectivity to aquatic ecosystems can explain patterns of Hg bioaccumulation in terrestrial consumers has not been well studied. Bats (Order: Chiroptera) can serve as a model system for illuminating the trophic transfer of Hg given their high dietary diversity and foraging links to both aquatic and terrestrial food webs. Here we quantitatively characterize the dietary correlates of long-term exposure to Hg across a diverse local assemblage of bats in Belize and more globally across bat species from around the world with a comparative analysis of hair samples. Our data demonstrate considerable interspecific variation in hair total Hg concentrations in bats that span three orders of magnitude across species, ranging from 0.04 mg/kg in frugivorous bats (Artibeus spp.) to 145.27 mg/kg in the piscivorous Noctilio leporinus. Hg concentrations showed strong phylogenetic signal and were best explained by dietary connectivity of bat species to aquatic food webs. Our results highlight that phylogeny can be predictive of Hg concentrations through similarity in diet and how interspecific variation in feeding strategies influences chronic exposure to Hg and enables movement of contaminants from aquatic to terrestrial ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pesticide-contaminated feeds in integrated grass carp aquaculture: toxicology and bioaccumulation.

Science.gov (United States)

Pucher, J; Gut, T; Mayrhofer, R; El-Matbouli, M; Viet, P H; Ngoc, N T; Lamers, M; Streck, T; Focken, U

2014-02-19

Effects of dissolved pesticides on fish are widely described, but little is known about effects of pesticide-contaminated feeds taken up orally by fish. In integrated farms, pesticides used on crops may affect grass carp that feed on plants from these fields. In northern Vietnam, grass carp suffer seasonal mass mortalities which may be caused by pesticide-contaminated plants. To test effects of pesticide-contaminated feeds on health and bioaccumulation in grass carp, a net-cage trial was conducted with 5 differently contaminated grasses. Grass was spiked with 2 levels of trichlorfon/fenitrothion and fenobucarb. Unspiked grass was used as a control. Fish were fed at a daily rate of 20% of body mass for 10 d. The concentrations of fenitrothion and fenobucarb in pond water increased over time. Effects on fish mortality were not found. Fenobucarb in feed showed the strongest effects on fish by lowering feed uptake, deforming the liver, increasing blood glucose and reducing cholinesterase activity in blood serum, depending on feed uptake. Fenobucarb showed increased levels in flesh in all treatments, suggesting bio-concentration. Trichlorfon and fenitrothion did not significantly affect feed uptake but showed concentration-dependent reduction of cholinesterase activity and liver changes. Fenitrothion showed bioaccumulation in flesh which was dependant on feed uptake, whereas trichlorfon was only detected in very low concentrations in all treatments. Pesticide levels were all detected below the maximum residue levels in food. The pesticide-contaminated feeds tested did not cause mortality in grass carp but were associated with negative physiological responses and may increase susceptibility to diseases.

Polybrominated diphenyl ethers in marine ecosystems of the American continents: foresight from current knowledge.

Science.gov (United States)

Shaw, Susan D; Kannan, Kurunthachalam

2009-01-01

Polybrominated diphenyl ethers (PBDEs) are a class of synthetic halogenated organic compounds used in commercial and household products, such as textiles, furniture, and electronics, to increase their flame ignition resistance and to meet fire safety standards. The demonstrated persistence, bioaccumulation, and toxic potential of these compounds in animals and in humans are of increasing concern. The oceans are considered global sinks for PBDEs, as higher levels are found in marine organisms than in terrestrial biota. For the past three decades, North America has dominated the world market demand for PBDEs, consuming 95% of the penta-BDE formulation. Accordingly, the PBDE concentrations in marine biota and people from North America are the highest in the world and are increasing. Despite recent restrictions on penta- and octa-BDE commercial formulations, penta-BDE containing products will remain a reservoir for PBDE release for years to come, and the deca-BDE formulation is still in high-volume use. In this paper, we review all available data on the occurrence and trends of PBDEs in the marine ecosystems (air, water, sediments, invertebrates, fish, seabirds, and marine mammals) of North and South America. We outline here our concerns about the potential future impacts of large existing stores of banned PBDEs in consumer products, and the vast and growing reservoirs of deca-BDE as well as new and naturally occurring brominated compounds on marine ecosystems.

Assessing the effects of seawater temperature and pH on the bioaccumulation of emerging chemical contaminants in marine bivalves.

Science.gov (United States)

Maulvault, Ana Luísa; Camacho, Carolina; Barbosa, Vera; Alves, Ricardo; Anacleto, Patrícia; Fogaça, Fabiola; Kwadijk, Christiaan; Kotterman, Michiel; Cunha, Sara C; Fernandes, José O; Rasmussen, Rie R; Sloth, Jens J; Aznar-Alemany, Òscar; Eljarrat, Ethel; Barceló, Damià; Marques, António

2018-02-01

Emerging chemical contaminants [e.g. toxic metals speciation, flame retardants (FRs) and perfluorinated compounds (PFCs), among others], that have not been historically recognized as pollutants nor their toxicological hazards, are increasingly more present in the marine environment. Furthermore, the effects of environmental conditions (e.g. temperature and pH) on bioaccumulation and elimination mechanisms of these emerging contaminants in marine biota have been poorly studied until now. In this context, the aim of this study was to assess, for the first time, the effect of warmer seawater temperatures (Δ = + 4°C) and lower pH levels (Δ = - 0.4 pH units), acting alone or combined, on the bioaccumulation and elimination of emerging FRs (dechloranes 602, 603 and 604, and TBBPA), inorganic arsenic (iAs), and PFCs (PFOA and PFOS) in two estuarine bivalve species (Mytilus galloprovincialis and Ruditapes philippinarum). Overall, results showed that warming alone or combined with acidification promoted the bioaccumulation of some compounds (i.e. dechloranes 602, 604, TBBPA), but also facilitated the elimination of others (i.e. iAs, TBBPA). Similarly, lower pH also resulted in higher levels of dechloranes, as well as enhanced iAs, PFOA and PFOS elimination. Data also suggests that, when both abiotic stressors are combined, bivalves' capacity to accumulate contaminants may be time-dependent, considering significantly drastic increase observed with Dec 602 and TBBPA, during the last 10 days of exposure, when compared to reference conditions. Such changes in contaminants' bioaccumulation/elimination patterns also suggest a potential increase of human health risks of some compounds, if the climate continues changing as forecasted. Therefore, this first study pointed out the urgent need for further research on the effects of abiotic conditions on emerging contaminants kinetics, to adequately estimate the potential toxicological hazards associated to these compounds and

Hydroxyl pyridine containing polybenzimidazole membranes for proton exchange membrane fuel cells

DEFF Research Database (Denmark)

Yang, Jingshuai; Xu, Yixin; Zhou, Lu

2013-01-01

A polybenzimidazole variant polymer containing hydroxyl pyridine groups, termed as OHPyPBI, was synthesized from 3,3'-diaminobenzidine tetrahydrochloride and 4-hydroxy-2,6-pyridinedicarboxylic acid. The thermal-oxidative stability of the OHPyPBI polymer was as high as that of poly[2,2'-(m-phenyle...

Assessing the effects of seawater temperature and pH on the bioaccumulation of emerging chemical contaminants in marine bivalves

DEFF Research Database (Denmark)

Maulvault, Ana Luísa; Camacho, Carolina; Barbosa, Vera

2017-01-01

Emerging chemical contaminants [e.g. toxic metals speciation, flame retardants (FRs) and perfluorinated compounds (PFCs), among others], that have not been historically recognized as pollutants nor their toxicological hazards, are increasingly more present in the marine environment. Furthermore......, the effects of environmental conditions (e.g. temperature and pH) on bioaccumulation and elimination mechanisms of these emerging contaminants in marine biota have been poorly studied until now. In this context, the aim of this study was to assess, for the first time, the effect of warmer seawater...... and Ruditapes philippinarum). Overall, results showed that warming alone or combined with acidification promoted the bioaccumulation of some compounds (i.e. dechloranes 602, 604, TBBPA), but also facilitated the elimination of others (i.e. iAs, TBBPA). Similarly, lower pH also resulted in higher levels...

Influence of particle characteristics and organic matter content on the bioavailability and bioaccumulation of pyrene by clams

International Nuclear Information System (INIS)

Verrengia Guerrero, N.R.; Taylor, M.G.; Wider, E.A.; Simkiss, K.

2003-01-01

An experimental model with artificial particles and humic acids describes bioavailability of sediment-bound pyrene to clams. - Hydrophobic chemicals are known to associate with sediment particles including those from both suspended particulate matter and bottom deposits. The complex and variable composition of natural particles makes it very difficult therefore, to predict the bioavailability of sediment-bound contaminants. To overcome these problems we have previously devised a test system using artificial particles, with or without humic acids, for use as an experimental model of natural sediments. In the present work we have applied this experimental technique to investigate the bioavailability and bioaccumulation of pyrene by the freshwater fingernail clam Sphaerium corneum. The uptake and accumulation of pyrene in clams exposed to the chemical in the presence of a sample of natural sediment was also investigated. According to the results obtained, particle surface properties and organic matter content are the key factors for assessing the bioavailability and bioaccumulation of pyrene by clams

Studies on bioaccumulation of 152Eu, 137Cs, 60Co by different algal genera

International Nuclear Information System (INIS)

Saha, A.K.; Chakraborty, N.; Pal, R.; Nayak, Dalia; Lahiri, Susanta

2006-01-01

In the present paper, the bioaccumulation of a mixture of potentially hazardous, long lived radionuclides 152 Eu, 137 Cs and 60 Co by five algal genera of three different family, viz.: Lyngbya and Phormidium from cyanophyceae; Phizoclonium and Chaetomorpha from chlorophyceae and Catenella from rhodophyceae have been studied. Because of the long half life and high solubility, these radionuclides are considered the most hazardous in the nuclear spent fuel

Reaction of single-standard DNA with hydroxyl radical generated by iron(II)-ethylenediaminetetraacetic acid

International Nuclear Information System (INIS)

Prigodich, R.V.; Martin, C.T.

1990-01-01

This study demonstrates that the reaction of Fe(II)-EDTA and hydrogen peroxide with the single-stranded nucleic acids d(pT) 70 and a 29-base sequence containing a mixture of bases results in substantial damage which is not directly detected by gel electrophoresis. Cleavage of the DNA sugar backbone is enhanced significantly after the samples are incubated at 90 degree C in the presence of piperidine. The latter reaction is used in traditional Maxam-Gilbert DNA sequencing to detect base damage, and the current results are consistent with reaction of the hydroxyl radical with the bases in single-stranded DNA (although reaction with sugar may also produce adducts that are uncleaved but labile to cleavage by piperidine). We the authors propose that hydroxyl radicals may react preferentially with the nucleic acid bases in ssDNA and that reaction of the sugars in dsDNA is dominant because the bases are sequestered within the double helix. These results have implications both for the study of single-stranded DNA binding protein binding sites and for the interpretation of experiments using the hydroxyl radical to probe DNA structure or to footprint double-stranded DNA binding protein binding sites

Probing the Differential Tissue Distribution and Bioaccumulation Behavior of Per- and Polyfluoroalkyl Substances of Varying Chain-Lengths, Isomeric Structures and Functional Groups in Crucian Carp.

Science.gov (United States)

Shi, Yali; Vestergren, Robin; Nost, Therese Haugdahl; Zhou, Zhen; Cai, Yaqi

2018-04-17

Understanding the bioaccumulation mechanisms of per- and polyfluoroalkyl substances (PFASs) across different chain-lengths, isomers and functional groups represents a monumental scientific challenge with implications for chemical regulation. Here, we investigate how the differential tissue distribution and bioaccumulation behavior of 25 PFASs in crucian carp from two field sites impacted by point sources can provide information about the processes governing uptake, distribution and elimination of PFASs. Median tissue/blood ratios (TBRs) were consistently 90% of the amount of PFASs in the organism. Principal component analyses of TBRs and RBBs showed that the functional group was a relatively more important predictor of internal distribution than chain-length for PFASs. Whole body bioaccumulation factors (BAFs) for short-chain PFASs deviated from the positive relationship with hydrophobicity observed for longer-chain homologues. Overall, our results suggest that TBR, RBB, and BAF patterns were most consistent with protein binding mechanisms although partitioning to phospholipids may contribute to the accumulation of long-chain PFASs in specific tissues.

Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

International Nuclear Information System (INIS)

Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

1999-01-01

The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage (''-OH'') of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures

Hydroxylation of nitro-(pentafluorosulfanyl)benzenes via vicarious nucleophilic substitution of hydrogen

Czech Academy of Sciences Publication Activity Database

Beier, Petr; Pastýříková, Tereza

2011-01-01

Roč. 52, č. 34 (2011), s. 4392-4394 ISSN 0040-4039 R&D Projects: GA ČR GAP207/11/0344 Institutional research plan: CEZ:AV0Z40550506 Keywords : pentafluorosulfanyl group * vicarious nucleophilic substitution * hydroxylation Subject RIV: CC - Organic Chemistry Impact factor: 2.683, year: 2011