Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

Energy Technology Data Exchange (ETDEWEB)

McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Alaee, Mehran [Environment Canada, 867 Lakeshore Rd., P.O. Box 5050, Burlington, ON L7R 4A6 (Canada); Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada)

2011-12-15

Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: > NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. > Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. > NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - {sup 1}H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

1H NMR-based metabolomics of time-dependent responses of Eisenia fetida to sub-lethal phenanthrene exposure

International Nuclear Information System (INIS)

Lankadurai, Brian P.; Wolfe, David M.; Simpson, Andre J.; Simpson, Myrna J.

2011-01-01

1 H NMR-based metabolomics was used to examine the response of the earthworm Eisenia fetida after exposure to sub-lethal concentrations of phenanthrene over time. Earthworms were exposed to 0.025 mg/cm 2 of phenanthrene (1/64th of the LC 50 ) via contact tests over four days. Earthworm tissues were extracted using a mixture of chloroform, methanol and water, resulting in polar and non-polar fractions that were analyzed by 1 H NMR after one, two, three and four days. NMR-based metabolomic analyses revealed heightened E. fetida responses with longer phenanthrene exposure times. Amino acids alanine and glutamate, the sugar maltose, the lipids cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. The conversion of succinate to fumarate in the Krebs cycle was also interrupted by phenanthrene. Therefore, this study shows that NMR-based metabolomics is a powerful tool for elucidating time-dependent relationships in addition to the mode of toxicity of phenanthrene in earthworm exposure studies. - Highlights: → NMR-based earthworm metabolomic analysis of the mode of action of phenanthrene is presented. → The earthworm species E. fetida were exposed to sub-lethal phenanthrene concentrations. → Both polar and non-polar metabolites of E. fetida tissue extracts were analyzed by 1 H NMR. → Longer phenanthrene exposure times resulted in heightened earthworm responses. → An interruption of the Krebs cycle was also observed due to phenanthrene exposure. - 1 H NMR metabolomics is used to determine the relationship between phenanthrene exposure and the metabolic response of the earthworm E. fetida over time and also to elucidate the phenanthrene mode of toxicity.

Exposure to Sublethal Doses of Fipronil and Thiacloprid Highly Increases Mortality of Honeybees Previously Infected by Nosema ceranae

Science.gov (United States)

Vidau, Cyril; Diogon, Marie; Aufauvre, Julie; Fontbonne, Régis; Viguès, Bernard; Brunet, Jean-Luc; Texier, Catherine; Biron, David G.; Blot, Nicolas; El Alaoui, Hicham; Belzunces, Luc P.; Delbac, Frédéric

2011-01-01

Background The honeybee, Apis mellifera, is undergoing a worldwide decline whose origin is still in debate. Studies performed for twenty years suggest that this decline may involve both infectious diseases and exposure to pesticides. Joint action of pathogens and chemicals are known to threaten several organisms but the combined effects of these stressors were poorly investigated in honeybees. Our study was designed to explore the effect of Nosema ceranae infection on honeybee sensitivity to sublethal doses of the insecticides fipronil and thiacloprid. Methodology/Finding Five days after their emergence, honeybees were divided in 6 experimental groups: (i) uninfected controls, (ii) infected with N. ceranae, (iii) uninfected and exposed to fipronil, (iv) uninfected and exposed to thiacloprid, (v) infected with N. ceranae and exposed 10 days post-infection (p.i.) to fipronil, and (vi) infected with N. ceranae and exposed 10 days p.i. to thiacloprid. Honeybee mortality and insecticide consumption were analyzed daily and the intestinal spore content was evaluated 20 days after infection. A significant increase in honeybee mortality was observed when N. ceranae-infected honeybees were exposed to sublethal doses of insecticides. Surprisingly, exposures to fipronil and thiacloprid had opposite effects on microsporidian spore production. Analysis of the honeybee detoxification system 10 days p.i. showed that N. ceranae infection induced an increase in glutathione-S-transferase activity in midgut and fat body but not in 7-ethoxycoumarin-O-deethylase activity. Conclusions/Significance After exposure to sublethal doses of fipronil or thiacloprid a higher mortality was observed in N. ceranae-infected honeybees than in uninfected ones. The synergistic effect of N. ceranae and insecticide on honeybee mortality, however, did not appear strongly linked to a decrease of the insect detoxification system. These data support the hypothesis that the combination of the increasing

Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

International Nuclear Information System (INIS)

McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A.; Alaee, Mehran; Simpson, Andre J.; Simpson, Myrna J.

2011-01-01

Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: → NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. → Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. → NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - 1 H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

{sup 1}H NMR-based metabolomics of time-dependent responses of Eisenia fetida to sub-lethal phenanthrene exposure

Energy Technology Data Exchange (ETDEWEB)

Lankadurai, Brian P.; Wolfe, David M.; Simpson, Andre J. [Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada (Canada)

2011-10-15

{sup 1}H NMR-based metabolomics was used to examine the response of the earthworm Eisenia fetida after exposure to sub-lethal concentrations of phenanthrene over time. Earthworms were exposed to 0.025 mg/cm{sup 2} of phenanthrene (1/64th of the LC{sub 50}) via contact tests over four days. Earthworm tissues were extracted using a mixture of chloroform, methanol and water, resulting in polar and non-polar fractions that were analyzed by {sup 1}H NMR after one, two, three and four days. NMR-based metabolomic analyses revealed heightened E. fetida responses with longer phenanthrene exposure times. Amino acids alanine and glutamate, the sugar maltose, the lipids cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. The conversion of succinate to fumarate in the Krebs cycle was also interrupted by phenanthrene. Therefore, this study shows that NMR-based metabolomics is a powerful tool for elucidating time-dependent relationships in addition to the mode of toxicity of phenanthrene in earthworm exposure studies. - Highlights: > NMR-based earthworm metabolomic analysis of the mode of action of phenanthrene is presented. > The earthworm species E. fetida were exposed to sub-lethal phenanthrene concentrations. > Both polar and non-polar metabolites of E. fetida tissue extracts were analyzed by {sup 1}H NMR. > Longer phenanthrene exposure times resulted in heightened earthworm responses. > An interruption of the Krebs cycle was also observed due to phenanthrene exposure. - {sup 1}H NMR metabolomics is used to determine the relationship between phenanthrene exposure and the metabolic response of the earthworm E. fetida over time and also to elucidate the phenanthrene mode of toxicity.

Repeated sublethal exposures to the sea lice pesticide Salmosan® (azamethiphos) on adult male lobsters (Homarus americanus) causes neuromuscular dysfunction, hypoxia, metabolic disturbances and mortality.

Science.gov (United States)

Dounia, Daoud; Andrea, Battison; Lefort, Natalie; Van Geest, Jordana Lynne

2016-12-01

In Atlantic Canada and other salmon-growing regions, treatment of sea lice infestations in salmon aquaculture is necessary to protect fish health. The product Salmosan®, which contains the organophosphate azamethiphos as the active ingredient, is a pesticide presently used for treatment against sea lice. It is applied as a bath treatment and then released into the surrounding seawater. The potential for lethality to non-target species following acute and chronic exposures to Salmosan® has been studied over the past decade, however, the potential for sublethal effects on lobsters remains a concern. Adult male lobsters were exposed to 0.06, 0.5, and 5µgL -1 azamethiphos for one hour, repeated five times, over 48h. Lobsters were assessed immediately after exposure and over six days of recovery. Inhibition of muscle cholinesterase activity was detected in lobsters exposed to 0.5 and 5µgL -1 azamethiphos. The 5µgL -1 dose was considered lethal (93% cumulative mortality). Significant changes in hemolymph plasma biochemistry were most apparent in the 5µgL -1 exposure group in the immediate post-exposure samples. Citrate synthase activity was significantly lower in muscles of the 0.5µgL -1 exposure group compared to control lobsters. Mean electron transport system and standard metabolic rates tended to be lower in muscle tissue of the 0.5µgL -1 exposure group than control group lobsters. These results suggest that sublethal effects on lobster energetics may occur under laboratory exposure conditions (i.e., concentrations and duration) considered environmentally relevant, which could result in impairment under natural conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Subchronic exposure to sublethal dose of imidacloprid changes electrophysiological properties and expression pattern of nicotinic acetylcholine receptor subtypes in insect neurosecretory cells.

Science.gov (United States)

Benzidane, Yassine; Goven, Delphine; Abd-Ella, Aly Ahmed; Deshayes, Caroline; Lapied, Bruno; Raymond, Valérie

2017-09-01

Neonicotinoids are the most important class of insecticides used in agriculture over the last decade. They act as selective agonists of insect nicotinic acetylcholine receptors (nAChRs). The emergence of insect resistance to these insecticides is one of the major problems, which limit the use of neonicotinoids. The aim of our study is to better understand physiological changes appearing after subchronic exposure to sublethal doses of insecticide using complementary approaches that include toxicology, electrophysiology, molecular biology and calcium imaging. We used cockroach neurosecretory cells identified as dorsal unpaired median (DUM) neurons, known to express two α-bungarotoxin-insensitive (α-bgt-insensitive) nAChR subtypes, nAChR1 and nAChR2, which differ in their sensitivity to imidacloprid. Although nAChR1 is sensitive to imidacloprid, nAChR2 is insensitive to this insecticide. In this study, we demonstrate that subchronic exposure to sublethal dose of imidacloprid differentially changes physiological and molecular properties of nAChR1 and nAChR2. Our findings reported that this treatment decreased the sensitivity of nAChR1 to imidacloprid, reduced current density flowing through this nAChR subtype but did not affect its subunit composition (α3, α8 and β1). Subchronic exposure to sublethal dose of imidacloprid also affected nAChR2 functions. However, these effects were different from those reported on nAChR1. We observed changes in nAChR2 conformational state, which could be related to modification of the subunit composition (α1, α2 and β1). Finally, the subchronic exposure affecting both nAChR1 and nAChR2 seemed to be linked to the elevation of the steady-state resting intracellular calcium level. In conclusion, under subchronic exposure to sublethal dose of imidacloprid, cockroaches are capable of triggering adaptive mechanisms by reducing the participation of imidacloprid-sensitive nAChR1 and by optimizing functional properties of nAChR2, which is

Exposure to Sub-lethal 2,4-Dichlorophenoxyacetic Acid Arrests Cell Division and Alters Cell Surface Properties in Escherichia coli

Science.gov (United States)

Bhat, Supriya V.; Kamencic, Belma; Körnig, André; Shahina, Zinnat; Dahms, Tanya E. S.

2018-01-01

Escherichia coli is a robust, easily adaptable and culturable bacterium in vitro, and a model bacterium for studying the impact of xenobiotics in the environment. We have used correlative atomic force – laser scanning confocal microscopy (AFM-LSCM) to characterize the mechanisms of cellular response to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). One of the most extensively used herbicides world-wide, 2,4-D is known to cause hazardous effects in diverse non-target organisms. Sub-lethal concentrations of 2,4-D caused DNA damage in E. coli WM1074 during short exposure periods which increased significantly over time. In response to 2,4-D, FtsZ and FtsA relocalized within seconds, coinciding with the complete inhibition of cell septation and cell elongation. Exposure to 2,4-D also resulted in increased activation of the SOS response. Changes to cell division were accompanied by concomitant changes to surface roughness, elasticity and adhesion in a time-dependent manner. This is the first study describing the mechanistic details of 2,4-D at sub-lethal levels in bacteria. Our study suggests that 2,4-D arrests E. coli cell division within seconds after exposure by disrupting the divisome complex, facilitated by dissipation of membrane potential. Over longer exposures, 2,4-D causes filamentation as a result of an SOS response to oxidative stress induced DNA damage. PMID:29472899

Effects Of Exposure To Sublethal Concentrations Of Azadirachta ...

African Journals Online (AJOL)

The physiological impairment on the fingerlings of Clarias gariepinus when exposed to sublethal concentrations of Azadirachta Indica was investigated. The fish were exposed to concentrations of 1.25, 2.50, 5.0, 10.0, 20.0 ML -1 for the period of 12 weeks. The crude protein content decreased with increased concentration ...

Effects of sublethal exposure to boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta.

Science.gov (United States)

Ali, Arshad; Xue, Rui-De; Barnard, Donald R

2006-09-01

Effects of sublethal exposure to 0.1% boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta were studied in the laboratory. Survival of males as well as females was significantly reduced when exposed to the bait, compared to control adults. The host-seeking and bloodfeeding activities in the baited females decreased, but the mean duration of blood engorgement (probing to voluntary withdrawal of proboscis) was not significantly different between the baited and control females. The landing and biting rates (human forearm) were significantly reduced in the baited females compared to nonbaited controls. Fecundity and fertility (based on number of laid eggs per female and percentage egg hatch, respectively) in the baited females were significantly reduced, and ovarian development was retarded. Sublethal exposure to sugar-based boric acid bait has the potential to reduce adult populations of St. albopicta.

Assessment of chronic sublethal effects of imidacloprid on honey bee colony health

Science.gov (United States)

Here we present results of a three-year study to determine the fate of imidacloprid residues in hive matrices and to assess chronic sublethal effects on whole honey bee colonies fed supplemental pollen diet containing imidacloprid at 5, 20 and 100 µg/kg over multiple brood cycles. Various endpoints ...

Sublethal Exposure to Diatomaceous Earth Increases Net Fecundity of Flour Beetles (Tribolium confusum) by Inhibiting Egg Cannibalism

Science.gov (United States)

Shostak, Allen W.

2014-01-01

Population regulation results from an interplay of numerous intrinsic and external factors, and for many insects cannibalism is such a factor. This study confirms a previously-reported observation that sublethal exposure to the fossilized remains of diatoms (i.e. diatomaceous earth) increases net fecundity (eggs produced minus eggs destroyed/day) of flour beetles, Tribolium confusum. The aim was to experimentally test two non-mutually-exclusive ecological mechanisms potentially responsible for the increased net fecundity: higher egg production and lower egg cannibalism. Adult T. confusum were maintained at low or high density in medium containing sublethal (0–4%) diatomaceous earth. Net fecundity increased up to 2.1× control values during diatomaceous earth exposure, and returned to control levels following removal from diatomaceous earth. Cannibalism assays on adults showed that diatomaceous earth reduced the number of eggs produced to 0.7× control values at low density and to 0.8× controls at high density, and also reduced egg cannibalism rates of adults to as little as 0.4× control values, but at high density only. Diatomaceous earth also reduced cannibalism by larvae on eggs to 0.3× control values. So, while the presence of diatomaceous earth reduced egg production, net fecundity increased as a result of strong suppression of the normal egg cannibalism by adults and larvae that occurs at high beetle density. Undisturbed cultures containing sublethal diatomaceous earth concentrations reached higher population densities than diatomaceous earth-free controls. Cohort studies on survival from egg to adult indicated that this population increase was due largely to decreased egg cannibalism by adult females. This is the first report of inhibition of egg cannibalism by diatomaceous earth on larval or adult insects. The ability of diatomaceous earth to alter cannibalism behavior without causing mortality makes it an ideal investigative tool for cannibalism

Effects of chlorimuron ethyl on terrestrial and wetland plants: Levels of, and time to recovery following sublethal exposure

International Nuclear Information System (INIS)

Carpenter, David; Boutin, Céline; Allison, Jane E.

2013-01-01

Current pesticide registration guidelines call for short-term testing of plants; long-term effects on vegetative parts and reproduction remain untested. The aims of our study were to determine level of recovery and recovery times for plants exposed to the sulfonylurea herbicide chlorimuron ethyl using data collected from single species, dose–response greenhouse experiments. The nine terrestrial and eight wetland species tested showed variable levels of recovery and recovery timeframes. Many species (six terrestrial and five wetland) were vegetatively stunted at sublethal doses and were reproductively impaired. Full recovery did not occur at all doses and maximum recovery times varied from 3 to 15 weeks in this controlled environment. In a complex community, affected species may be displaced by tolerant species, through interspecific competition, before they fully recover. It is plausible that individual populations could be diminished or eliminated through reduced seedbank inputs (annuals and perennials) and asexual reproduction (perennials). - Highlights: ► Native terrestrial and wetland plants were used to assess the risks of herbicide drift. ► Vegetative and reproductive health endpoints were evaluated over time. ► Recovery rates were found to be both species and dose dependant. ► Reproductive recovery does not always equal vegetative recovery. ► Susceptible species may be displaced by resilient or resistant species. - Capsule: This study serves to bridge the gap between simplified short-term greenhouse tests and effects of herbicides on recovery of non-target plant species after sublethal exposures.

Acute and sub-lethal exposure to copper oxide nanoparticles causes oxidative stress and teratogenicity in zebrafish embryos.

Science.gov (United States)

Ganesan, Santhanamari; Anaimalai Thirumurthi, Naveenkumar; Raghunath, Azhwar; Vijayakumar, Savitha; Perumal, Ekambaram

2016-04-01

Nano-copper oxides are a versatile inorganic material. As a result of their versatility, the immense applications and usage end up in the environment causing a concern for the lifespan of various beings. The ambiguities surround globally on the toxic effects of copper oxide nanoparticles (CuO-NPs). Hence, the present study endeavored to study the sub-lethal acute exposure effects on the developing zebrafish embryos. The 48 hpf LC50 value was about 64 ppm. Therefore, we have chosen the sub-lethal dose of 40 and 60 ppm for the study. Accumulation of CuO-NPs was evidenced from the SEM-EDS and AAS analyzes. The alterations in the AChE and Na(+)/K(+)-ATPase activities disrupted the development process. An increment in the levels of oxidants with a concomitant decrease in the antioxidant enzymes confirmed the induction of oxidative stress. Oxidative stress triggered apoptosis in the exposed embryos. Developmental anomalies were observed with CuO-NPs exposure in addition to oxidative stress in the developing embryos. Decreased heart rate and hatching delay hindered the normal developmental processes. Our work has offered valuable data on the connection between oxidative stress and teratogenicity leading to lethality caused by CuO-NPs. A further molecular mechanism unraveling the uncharted connection between oxidative stress and teratogenicity will aid in the safe use of CuO-NPs. Copyright © 2015 John Wiley & Sons, Ltd.

Sublethal effect of imidacloprid on Solenopsis invicta (Hymenoptera: Formicidae) feeding, digging, and foraging behavior

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There is increasing evidence that exposure to neonicotinoid insecticides at sublethal levels impairs colonies of honeybee and other pollinators. Recently, it was found that sublethal contamination with neonicotinoids also affect growth and behavior of ants. In this study, we exposed red imported fi...

Survival rate of honeybee (Apis mellifera) workers after exposure to sublethal concentrations of imidacloprid

NARCIS (Netherlands)

Blacquiere, T.

2010-01-01

Imidacloprid is a commonly used systemic insecticide which can induce several sublethal effects. Previous research has not shown any increased mortality in bees that were fed with sublethal doses. However, there is very little research conducted with the focus on survival rate of honeybees in the

Chronic exposure to sublethal doses of radiation mimetic ZeocinTM selects for clones deficient in homologous recombination

International Nuclear Information System (INIS)

Delacote, Fabien; Deriano, Ludovic; Lambert, Sarah; Bertrand, Pascale; Saintigny, Yannick; Lopez, Bernard S.

2007-01-01

DNA double-strand breaks (DSBs) are highly toxic lesions leading to genome variability/instability. The balance between homologous recombination (HR) and non-homologous end-joining (NHEJ), two alternative DSB repair systems, is essential to ensure genome maintenance in mammalian cells. Here, we transfected CHO hamster cells with the pcDNA TM 3.1/Zeo plasmid, and selected transfectants with Zeocin TM , a bleomycin analog which produces DSBs. Despite the presence of a Zeocin TM resistance gene in pcDNA TM 3.1/Zeo, Zeocin TM induced 8-10 γ-H2AX foci per cell. This shows that the Zeocin TM resistance gene failed to fully detoxify cells treated with Zeocin TM , and that during selection cells were submitted to a chronic sublethal DSB stress. Selected clones show decreases in both spontaneous and induced intrachromosomal HR. In contrast, in an in vitro assay, these clones show an increase in NHEJ products specific to the KU86 pathway. We selected cells, in the absence of pcDNA TM 3.1/Zeo, with low and sublethal doses of Zeocin TM , producing a mean 8-10 γ-H2AX foci per cell. Newly selected clones exhibited similar phenotypes: HR decrease accompanied by an increase in KU86-dependent NHEJ efficiency. Thus chronic exposure to sublethal numbers of DSBs selects cells whose HR versus NHEJ balance is altered. This may well have implications for radio- and chemotherapy, and for management of environmental hazards

Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

Science.gov (United States)

Flores, Florita; Hoogenboom, Mia O.; Smith, Luke D.; Cooper, Timothy F.; Abrego, David; Negri, Andrew P.

2012-01-01

Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l−1 TSS (25 mg cm−2 day−1) for M. aequituberculata and 100 mg l−1 TSS (83 mg cm−2 day−1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue. PMID:22662225

Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts.

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Florita Flores

Full Text Available Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata more than the upright branching species (Acropora millepora. The lowest sediment treatments that caused full colony mortality were 30 mg l(-1 TSS (25 mg cm(-2 day(-1 for M. aequituberculata and 100 mg l(-1 TSS (83 mg cm(-2 day(-1 for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue.

Acclimation-induced changes in toxicity and induction of metallothionein-like proteins in the fathead minnow following sublethal exposure to cobalt, silver, and zinc

International Nuclear Information System (INIS)

Hobson, J.F.

1986-01-01

Increases in tolerance and resistance to metal toxicity by aquatic organisms have been linked to elevated levels of low-molecular-weight metal-binding proteins (e.g., metallothioneins). Acclimation-induced changes in toxic response and the concentration of metallothionein-like proteins (MTP) were studied in laboratory populations of the fathead minnow, Pimephales promelas, following sublethal exposure to Co, Ag, and Zn. Following 7 and 14 days of sublethal exposure, tolerance and resistance, as measured by acute toxicity values, were altered in a dose dependent fashion. Acute toxicity values returned to control levels after 21 days of continuous exposure. Tolerance and resistance of Co- and Zn-acclimated animals were depressed after a 7-day post-acclimation period in control water. Tolerance and resistance of Ag-acclimated animals were temporarily enhanced after 7 days post-acclimation and returned to control levels after 14 days. Accumulation of Co, Ag, and Zn measured as wholebody residues appeared to be regulated in 4 of 6 exposure regimes with residues reaching stable levels after 7 to 14 days of exposure. MTP was induced by exposure to 1.8 mg Zn/L and 0.01 mg Ag/L, however, no sustained (i.e., post 21 days) tolerance or resistance were observed at these dose levels indicating that these two biological responses may not be directly related

Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae

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Zhengyu Huang

2015-05-01

Full Text Available The diamondback moth, Plutella xylostella (Linnaeus (Lepidoptera: Plutellidae, is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations. Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management.

Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae).

Science.gov (United States)

Huang, Zhengyu; Zhang, Yalin

2015-05-29

The diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations) and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations). Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management.

Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae)

Science.gov (United States)

Huang, Zhengyu; Zhang, Yalin

2015-01-01

The diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations) and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations). Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management. PMID:26035491

Contact Irritant Responses of Aedes aegypti Using Sublethal Concentration and Focal Application of Pyrethroid Chemicals

OpenAIRE

Manda, Hortance; Shah, Pankhil; Polsomboon, Suppaluck; Chareonviriyaphap, Theeraphap; Castro-Llanos, Fanny; Morrison, Amy; Burrus, Roxanne G.; Grieco, John P.; Achee, Nicole L.

2013-01-01

BACKGROUND: Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. METHODS: Cont...

Exposure to sublethal concentrations of tributyltin reduced survival, growth, and 20-hydroxyecdysone levels in a marine mysid.

Science.gov (United States)

Kim, Bo-Mi; Saravanan, Manoharan; Lee, Do-Hee; Kang, Jung-Hoon; Kim, Moonkoo; Jung, Jee-Hyun; Rhee, Jae-Sung

2018-06-07

Tributyltin (TBT) is as an antifouling organotin compound used in boat paints. Although organotin-based antifouling agents have been banned on a global scale, the mode of action of TBT has been studied in numerous aquatic species because of its toxicity, persistence, bioaccumulation potential, and endocrine-disrupting characteristics. In this study, we conducted 96-h acute toxicity tests wherein we exposed juvenile and adult marine mysids to waterborne TBT. Over 4 weeks of exposure, mortality was dose-dependently increased in juveniles and adult mysids. To test sublethal effects of TBT on juvenile development, newborn juvenile mysids were exposed to 1, 5, or 10 ng L -1  TBT for 4 weeks. Subsequently, we measured morphological growth parameters and quantified the hormone ecdysterone (20-hydroxyecdysone: 20E), which controls molting in mysids. The lengths of the whole body, antennal scale, exopod, endopod, and telson were significantly smaller in the 5 and/or 10 ng L -1 TBT-exposed juvenile mysids than in control and DMSO-exposed groups. Levels of 20E were significantly lower at 5 and 10 ng L -1  TBT exposures. Additionally, the number of newly hatched juveniles was significantly lower from females previously exposed to 10 ng L -1  TBT. Our results indicate sublethal concentrations of TBT have inhibitory effects on the survival, growth, and production of juveniles. The lower 20E levels could be strongly associated with TBT-triggered inhibition. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

Energy Technology Data Exchange (ETDEWEB)

Pavlikova, Nela, E-mail: nela.pavlikova@lf3.cuni.cz [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Smetana, Pavel [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Halada, Petr [Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague (Czech Republic); Kovar, Jan [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic)

2015-10-15

Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

International Nuclear Information System (INIS)

Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

2015-01-01

Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

Assessment of Chronic Sublethal Effects of Imidacloprid on Honey Bee Colony Health

Science.gov (United States)

Dively, Galen P.; Embrey, Michael S.; Kamel, Alaa; Hawthorne, David J.; Pettis, Jeffery S.

2015-01-01

Here we present results of a three-year study to determine the fate of imidacloprid residues in hive matrices and to assess chronic sublethal effects on whole honey bee colonies fed supplemental pollen diet containing imidacloprid at 5, 20 and 100 μg/kg over multiple brood cycles. Various endpoints of colony performance and foraging behavior were measured during and after exposure, including winter survival. Imidacloprid residues became diluted or non-detectable within colonies due to the processing of beebread and honey and the rapid metabolism of the chemical. Imidacloprid exposure doses up to 100 μg/kg had no significant effects on foraging activity or other colony performance indicators during and shortly after exposure. Diseases and pest species did not affect colony health but infestations of Varroa mites were significantly higher in exposed colonies. Honey stores indicated that exposed colonies may have avoided the contaminated food. Imidacloprid dose effects was delayed later in the summer, when colonies exposed to 20 and 100 μg/kg experienced higher rates of queen failure and broodless periods, which led to weaker colonies going into the winter. Pooled over two years, winter survival of colonies averaged 85.7, 72.4, 61.2 and 59.2% in the control, 5, 20 and 100 μg/kg treatment groups, respectively. Analysis of colony survival data showed a significant dose effect, and all contrast tests comparing survival between control and treatment groups were significant, except for colonies exposed to 5 μg/kg. Given the weight of evidence, chronic exposure to imidacloprid at the higher range of field doses (20 to 100 μg/kg) in pollen of certain treated crops could cause negative impacts on honey bee colony health and reduced overwintering success, but the most likely encountered high range of field doses relevant for seed-treated crops (5 μg/kg) had negligible effects on colony health and are unlikely a sole cause of colony declines. PMID:25786127

Do Biopesticides Affect the Demographic Traits of a Parasitoid Wasp and Its Biocontrol Services through Sublethal Effects?

Science.gov (United States)

Biondi, Antonio; Zappalà, Lucia; Stark, John D.; Desneux, Nicolas

2013-01-01

Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM) programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®), emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae), on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae). Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment) and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life-history variables

Gulf of Mexico offshore operations monitoring experiment (GOOMEX), phase I : sublethal responses to contaminant exposure - introduction and overview

International Nuclear Information System (INIS)

Kennicutt, M.C.; Green, R.H.; Montagna, P.

1996-01-01

The Gulf of Mexico Offshore Operations Monitoring Experiment (GOOMEX) is a three-phase study to test and evaluate a range of biological, biochemical, and chemical methodologies to detect and assess chronic sublethal biological impacts in the vicinity of long-duration activities associated with oil and gas exploration and production. A chronic impact is defined as an effect on the biota caused by exposure to the long-term accumulation of chemicals in the environment. The basic program, comprising four field activities over a 2-yr period, was designed to detect nearfield impacts and contaminant gradients extending out from each site. Five test sites were evaluated and three selected as most appropriate for long-term study: MU-A85, MAI-686, and HI-A389. The sampling design included a radial pattern with stations at 30-50, 100, 200, 500, and 3000 m distance and employed a dose-response model to test the hypotheses that biological, chemical, and biochemical variations are due to platform-derived contaminants. Study components included contaminant (trace metals and hydrocarbons) analysis in sediments, pore waters, and biological tissues; assemblage analysis of benthic meiofauna, infauna, and epifauna, assessment of community health based on life history and reproduction studies; and the induction of detoxification responses. (author). 57 refs., 9 tabs., 5 figs

Sublethal and hormesis effects of imidacloprid on the soybean aphid Aphis glycines.

Science.gov (United States)

Qu, Yanyan; Xiao, Da; Li, Jinyu; Chen, Zhou; Biondi, Antonio; Desneux, Nicolas; Gao, Xiwu; Song, Dunlun

2015-04-01

The soybean aphid, Aphis glycines Matsumura, is a major pest in soybean crop. Current management of this pest relies mainly on insecticides applications, and the neonicotinoid imidacloprid has been proposed as an effective insecticide to control A. glycines in soybean field. Imidacloprid at lethal concentrations not only exerts acute toxicity to A. glycines, but also cause various biological changes when aphids are chronically exposed to lower concentrations. In this study, we assessed the effects of a low-lethal (0.20 mg L(-1)) and two sublethal (0.05 and 0.10 mg L(-1)) imidacloprid concentrations on various A. glycines life history traits. Aphid exposure to 0.20 mg L(-1) imidacloprid caused slower juvenile development, shorter reproductive period, and reduced adult longevity, fecundity and total lifespan. Stimulatory effects, i.e. hormesis, on reproduction and immature development duration were observed in aphids exposed to the lower sublethal imidacloprid concentrations. Consequently, the net reproduction rate (R 0) was significantly higher than in the control aphids. These findings stress the importance of the actual imidacloprid concentration in its toxicological properties on A. glycines. Therefore, our results would be useful for assessing the overall effects of imidacloprid on A. glycines and for optimizing integrated pest management programs targeting this pest.

Sublethal Toxic effects of spent Oil Based Drilling Mud and Cuttings ...

African Journals Online (AJOL)

Sublethal toxic effects of spent oil based drilling mud collected from an abandoned oil drilling site in Mpanak, Akwa Ibom State, Nigeria were assessed in the earthworm Aporrectodea longa. The test annelid was exposed to sub-lethal Concentration of 0ppm SPP; 62,500ppm SPP; 125, 000ppm SPP; 250,000ppm SPP and ...

Host defenses in experimental scrub typhus: effect of sublethal gamma radiation

International Nuclear Information System (INIS)

Kelly, D.J.

1983-01-01

The effect of sublethal gamma radiation on inbred mice chronically infected with scrub typhus rickettsiae was examined. Inbred mice which have been inoculated with Gilliam or Karp strain of Rickettsia tsutsugamushi by the subcutaneous route harbored the infection for at least one year. Irradiation of these animals at 12 or 52 weeks post inoculation at normally sublethal levels induced a significantly higher percentage of rickettsemic mice (recrudescence) than in the unirradiated similarly infected control animals. In addition, sublethal irradiation at 12 weeks also induced a quantitative increase in total rickettsiae. Homologous antibody titers to the rickettsiae were examined for five weeks following irradiation to determine the role of the humoral response in radiation induced recrudescence. Modification of recrudescence was investigated using radioprotective drugs. The expected results of this investigation supported the conclusion that the recrudescence of a chronic rickettsial infection in the appropriate host following immunological impairment due to battlefield or clinical exposure to gamma radiation can result in an acute, possibly lethal rickettsemia

Histological examination of sublethal effects of diazinon on ovary of bluegill, Lepomis macrochirus

International Nuclear Information System (INIS)

Dutta, H.M.; Maxwell, L.B.

2003-01-01

Sublethal doses of diazinon can alter microscopic anatomy of fish ovary. - The effects of the insecticide, diazinon (an organophosphorous compound), on the ovaries of bluegill (Lepomis macrohirus) were studied. Histological preparations of bluegill ovarian tissue was examined at 24, 48, 72 and 96 h and 1, 2 and 3 weeks following exposure to sublethal doses of diazinon (60 μg/l). The control contained primary follicles with an intact ovigerous lamellae and tunica albuginea. The control also revealed well developed stage IV oocytes with properly distributed provitelline nucleoli. After 24 h of exposure to diazinon, primary follicles began to show adhesion and cytoplasmic retraction in oocyte II occured. Cytoplasmic degeneration and additional adhesion and more retraction were visible at 48 h in oocyte II; 72 h brought forth adhesion, retraction and cytoplamic expulsion from oocyte IV. The number of atretic oocytes increased. Damages to the oocyte IV started to occur after 72 h of exposure. Cytoplasmic retraction and clumping was more visible at 96 h in oocyte IV. Partial destruction of the ovigerous lamellae and vitellogenic membrane occurred after 1 week. Two weeks continued to reveal destruction of follicles. Severe damage of the ovigerous lamellae, increased intrafollicular spaces, vacuolated cytoplasm, extrusion of karyoplasm and necrosis in the cytoplasm were most evident following 3 weeks of exposure. The ovarian wall became frayed and broken. Additionally, a marked increase of atretic follicles, shrinkage, and embedded nucleoli into the surrounding cytoplasm in oocyte II, III and IV were observed at week 3. This study revealed that oocytes at their different stages of maturation get affected differently at various exposure. Based on observations of the ovarian tissue compositional and structural changes following given exposure times, it becomes evident that consistent sublethal doses of diazinon can and will alter microscopic anatomy of the fish ovary

Histological examination of sublethal effects of diazinon on ovary of bluegill, Lepomis macrochirus

Energy Technology Data Exchange (ETDEWEB)

Dutta, H.M.; Maxwell, L.B

2003-01-01

Sublethal doses of diazinon can alter microscopic anatomy of fish ovary. - The effects of the insecticide, diazinon (an organophosphorous compound), on the ovaries of bluegill (Lepomis macrohirus) were studied. Histological preparations of bluegill ovarian tissue was examined at 24, 48, 72 and 96 h and 1, 2 and 3 weeks following exposure to sublethal doses of diazinon (60 {mu}g/l). The control contained primary follicles with an intact ovigerous lamellae and tunica albuginea. The control also revealed well developed stage IV oocytes with properly distributed provitelline nucleoli. After 24 h of exposure to diazinon, primary follicles began to show adhesion and cytoplasmic retraction in oocyte II occured. Cytoplasmic degeneration and additional adhesion and more retraction were visible at 48 h in oocyte II; 72 h brought forth adhesion, retraction and cytoplamic expulsion from oocyte IV. The number of atretic oocytes increased. Damages to the oocyte IV started to occur after 72 h of exposure. Cytoplasmic retraction and clumping was more visible at 96 h in oocyte IV. Partial destruction of the ovigerous lamellae and vitellogenic membrane occurred after 1 week. Two weeks continued to reveal destruction of follicles. Severe damage of the ovigerous lamellae, increased intrafollicular spaces, vacuolated cytoplasm, extrusion of karyoplasm and necrosis in the cytoplasm were most evident following 3 weeks of exposure. The ovarian wall became frayed and broken. Additionally, a marked increase of atretic follicles, shrinkage, and embedded nucleoli into the surrounding cytoplasm in oocyte II, III and IV were observed at week 3. This study revealed that oocytes at their different stages of maturation get affected differently at various exposure. Based on observations of the ovarian tissue compositional and structural changes following given exposure times, it becomes evident that consistent sublethal doses of diazinon can and will alter microscopic anatomy of the fish ovary.

Effect of lethal and sub-lethal concentrations of tobacco (Nicotiana ...

African Journals Online (AJOL)

Lethal and sub-lethal bioassays on Clarias gariepinus were conducted to evaluate the toxicity of tobacco (Nicotiana tobaccum) leaf dust on weight gain and haematological indices of Clarias gariepinus (mean weight 10.5±0.70g) in glass aquaria with aeration system. The concentrations used during the lethal exposure are: ...

Sublethal dose of phoxim and Bombyx mori nucleopolyhedrovirus interact to elevate silkworm mortality.

Science.gov (United States)

Gu, ZhiYa; Li, FanChi; Hu, JingSheng; Ding, Chao; Wang, Chaoqian; Tian, JiangHai; Xue, Bin; Xu, KaiZun; Shen, WeiDe; Li, Bing

2017-03-01

Silkworm (Bombyx mori) is an economically important insect. It is relatively less resistant to certain chemicals and environment exposures such as pesticides and pathogens. After pesticide exposures, the silkworms are more susceptible to microbial infections. The mechanism underlying the susceptibility might be related to immune response and oxidative stress. A sublethal dose of phoxim combined with Bombyx mori nucleopolyhedrovirus (BmNPV) elevated the silkworm mortality at 96 h. We found a higher content of H 2 O 2 and increased levels of genes related to oxidative stress and immune response after treatment with a sublethal dose of phoxim for 24 h or 48 h. However, such response decreased with longer pesticide treatment. Mortality increased by 44% when B. mori was exposed to combined treatment with BmNPV and phoxim rather than BmNPV alone. The level of examined immune-related and oxidative-stress-related genes significantly decreased in the combined treatment group compared with the BmNPV group. Our results indicated that, with long-term exposure to pesticides such as OPs, even at sublethal dose, the oxidative stress response and immune responses in silkworm were inhibited, which may lead to further immune impairment and accumulation of oxidative stress, resulting in susceptibility to the virus and harm to the silkworm. Our study provided insights for understanding the susceptibility to pathogen after pesticide exposures, which may promote the development of better pesticide controls to avoid significant economic losses. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Sub-lethal effects of neonicitinoids on the alfalfa leafcutter bee, Megachile rotundata

Science.gov (United States)

Neonicotinoids are commonly used pesticides in U.S. agriculture. For many beneficial insect species, lethal effects of neonicotinoids are well-documented; however, much less is known about sublethal exposure. The alfalfa leaf cutter bee Megachile rotundata is a managed pollinator that constructs com...

Do biopesticides affect the demographic traits of a parasitoid wasp and its biocontrol services through sublethal effects?

Directory of Open Access Journals (Sweden)

Antonio Biondi

Full Text Available Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®, emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae, on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae. Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life

Toxic effects of sublethal concentrations of diethyl Phthalate on the ...

African Journals Online (AJOL)

An investigation on the effect of Diethyl phthalate (DEP) on the gill of the African catfish Clarias gariepinus was carried out in the laboratory. Seventy-five (75) catfish fingerlings were subjected to continuous exposure to sublethal concentrations of DEP (30, 40, 60 and 80 ìg/L) for a period of four weeks. The gills of the catfish ...

Effects of Sublethal Concentrations of Insecticides on the Functional Response of Two Mirid Generalist Predators.

Directory of Open Access Journals (Sweden)

Angeliki F Martinou

Full Text Available The use of agrochemicals particularly pesticides, can hamper the effectiveness of natural enemies, causing disruption in the ecosystem service of biological control. In the current study, the effects of the insecticides thiacloprid and chlorantraniliprole on the functional response curves were assessed for two mirid predator nymphs, Macrolophus pygmaeus Rambur and Nesidiocoris tenuis Reuter. In the absence of insecticides, both predators exhibited a type II functional response when feeding on eggs of the moth Ephestia kuehniella. N. tenuis seems to be a more efficient predator than M. pygmaeus, as model estimated handling time was significantly lower for the former than for the latter. Residual exposure of M. pygmaeus to sublethal concentrations of either insecticide was associated with a change in the asymptote but not the type of the functional response curve. Thiacloprid seems to be the least compatible with M. pygmaeus, as it led to both a significant reduction of the attack rate and an increase in handling time. In contrast, chlorantraniliprole exposure significantly increased the handling time, but not the attack rate of the predator. Residual exposure of N. tenuis to sublethal concentrations of either insecticide did not have a significant effect on the type nor the parameters of the functional response model. The results show that pesticide residues that do not have lethal effects on beneficial arthropods can reduce prey consumption depending on predator species and on likely risks associated with toxicity.

Effects of Sublethal Concentrations of Insecticides on the Functional Response of Two Mirid Generalist Predators.

Science.gov (United States)

Martinou, Angeliki F; Stavrinides, Menelaos C

2015-01-01

The use of agrochemicals particularly pesticides, can hamper the effectiveness of natural enemies, causing disruption in the ecosystem service of biological control. In the current study, the effects of the insecticides thiacloprid and chlorantraniliprole on the functional response curves were assessed for two mirid predator nymphs, Macrolophus pygmaeus Rambur and Nesidiocoris tenuis Reuter. In the absence of insecticides, both predators exhibited a type II functional response when feeding on eggs of the moth Ephestia kuehniella. N. tenuis seems to be a more efficient predator than M. pygmaeus, as model estimated handling time was significantly lower for the former than for the latter. Residual exposure of M. pygmaeus to sublethal concentrations of either insecticide was associated with a change in the asymptote but not the type of the functional response curve. Thiacloprid seems to be the least compatible with M. pygmaeus, as it led to both a significant reduction of the attack rate and an increase in handling time. In contrast, chlorantraniliprole exposure significantly increased the handling time, but not the attack rate of the predator. Residual exposure of N. tenuis to sublethal concentrations of either insecticide did not have a significant effect on the type nor the parameters of the functional response model. The results show that pesticide residues that do not have lethal effects on beneficial arthropods can reduce prey consumption depending on predator species and on likely risks associated with toxicity.

Sublethal Dosage of Imidacloprid Reduces the Microglomerular Density of Honey Bee Mushroom Bodies

Science.gov (United States)

Peng, Yi-Chan; Yang, En-Cheng

2016-01-01

The dramatic loss of honey bees is a major concern worldwide. Previous studies have indicated that neonicotinoid insecticides cause behavioural abnormalities and have proven that exposure to sublethal doses of imidacloprid during the larval stage decreases the olfactory learning ability of adults. The present study shows the effect of sublethal doses of imidacloprid on the neural development of the honey bee brain by immunolabelling synaptic units in the calyces of mushroom bodies. We found that the density of the synaptic units in the region of the calyces, which are responsible for olfactory and visual functions, decreased after being exposed to a sublethal dose of imidacloprid. This not only links a decrease in olfactory learning ability to abnormal neural connectivity but also provides evidence that imidacloprid damages the development of the nervous system in regions responsible for both olfaction and vision during the larval stage of the honey bee. PMID:26757950

Lethal and sublethal effects of azadirachtin on the bumblebee Bombus terrestris (Hymenoptera: Apidae).

Science.gov (United States)

Barbosa, Wagner Faria; De Meyer, Laurens; Guedes, Raul Narciso C; Smagghe, Guy

2015-01-01

Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and sublethal effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L(-1)). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L(-1). Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L(-1). Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L(-1). At 3.2 mg L(-1), azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the sublethal effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L(-1). Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of sublethal effects. Taking into account that sublethal effects are as important as lethal effects for the development and survival of the colonies of B. terrestris

Addressing the recovery of feeding rates in post-exposure feeding bioassays: Cyathura carinata as a case study

Energy Technology Data Exchange (ETDEWEB)

Pais-Costa, Antonia Juliana [IMAR—Institute of Marine Research, MARE—Marine and Environmental Sciences Centre, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra (Portugal); Acevedo, Pelayo [SaBio IREC, Instituto de Investigación en Recursos Cinegéticos (UCLM-CSIC-JCCM), Ciudad Real 13005 (Spain); Marques, João Carlos [IMAR—Institute of Marine Research, MARE—Marine and Environmental Sciences Centre, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra (Portugal); Martinez-Haro, Mónica, E-mail: monica.martinezharo@gmail.com [IMAR—Institute of Marine Research, MARE—Marine and Environmental Sciences Centre, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra (Portugal)

2015-02-15

Post-exposure bioassays are used in environmental assessment as a cost-effective tool, but the effects of organism's recovery after exposure to pollutant has not yet been addressed in detail. The recoveries of post-exposure feeding rates after being exposed to two sublethal concentrations of cadmium during two different exposure periods (48 h and 96 h) were evaluated under laboratory conditions using the estuarine isopod Cyathura carinata. Results showed that feeding depression was a stable endpoint up to 24 h after cadmium exposure, which is useful for ecotoxicological bioassays. - Highlights: • We studied recovery of post-exposure feeding rates 48–96 h after cadmium exposure. • The assay is based on the isopod Cyathura carinata. • Post-exposure feeding inhibition is a stable sublethal endpoint.

Pesticides and Arthropods: Sublethal Effects and Demographic Toxicology

Directory of Open Access Journals (Sweden)

Dejan Marčić

2007-01-01

Full Text Available Insecticides and acaricides designed to control primary harmful insects and mites may also variously affect some other arthopods present in an (agroecosystem (e.g. secondary pests, predators, parasitoids, saprophytes, bioindicators, pollinators. Apart from insecticides and acaricides, arthropods may also be affected by the activity of other pesticides (fungicides, herbicides, etc.. Regardless of whether they are deemed desirable or not, the effects that pesticides have on arthopods need to be quantified as closely as possible through appropriate experimental procedures. Data acquired in tests designed to determined LD50/LC50 values are inadequate for evaluation of pesticide effectiveness in the field as pesticidesalso cause various sublethal effects, generally disregarded in such investigations. The sublethal effects of pesticides refer to any altered behaviour and/or physiology of individuals that have survived exposure to pesticides at doses/concentrations that can be lethal(within range causing mortality in an experimental population that exceeds mortality in an untreated population or sublethal (below that range. Pesticides affect locomotion and mobility, stimulate dispersion of arthropods from treated areas, complicate or prevent their navigation, orientation and ability to locate hosts, and cause changes in their feeding, mating and egg-laying patterns. Sublethal pesticide effects on arthropod physiology reflect on the life span, rate of development, fecundity and/or fertility, sex ratio and immunity of surviving individuals. Different parameters are being used in arthropod bioassays to determine sublethal effects (ED50/EC50, LOEC, NOEC, total effect index. Compared to acute toxicity tests, these parameters improve the quality of evaluation and create a more accurate view of the effects of a pesticide. However, such approach covers mainly fecundity/fertility alone, while all other sublethal effects remain unaccounted for. Besides, it

Vertical transmission of sublethal granulovirus infection in the Indian meal moth, Plodia interpunctella.

Science.gov (United States)

Burden, J P; Griffiths, C M; Cory, J S; Smith, P; Sait, S M

2002-03-01

Knowledge of the mechanisms of pathogen persistence in relation to fluctuations in host density is crucial to our understanding of disease dynamics. In the case of insect baculoviruses, which are typically transmitted horizontally via a lifestage that can persist outside the host, a key issue that remains to be elucidated is whether the virus can also be transmitted vertically as a sublethal infection. We show that RNA transcripts for the Plodia interpunctella GV granulin gene are present in a high proportion of P. interpunctella insects that survive virus challenge. Granulin is a late-expressed gene that is only transcribed after viral genome replication, its presence thus strongly indicates that viral genome replication has occurred. Almost all insects surviving the virus challenge tested positive for viral RNA in the larval and pupal stage. However, this proportion declined in the emerging adults. Granulin mRNA was also detected in both the ovaries and testes, which may represent a putative mechanism by which reduced fecundity in sublethally affected hosts might be manifested. RNA transcripts were also detected in 60-80% of second-generation larvae that were derived from mating surviving adults, but there was no difference between the sexes, with both males and females capable of transmitting a sublethal infection to their offspring. The data indicate that low-level persistent infection, with at least limited gene expression, can occur in P. interpunctella following survival of a granulovirus challenge. We believe that this is the first demonstration of a persistent, sublethal infection by a baculovirus to be initiated by a sublethal virus dose. We hypothesize that the 'latent' baculovirus infections frequently referred to in the literature may also be low level persistent, sublethal infections resulting from survival from initial baculovirus exposure.

Sublethal effects of carbaryl on embryonic and gonadal ...

African Journals Online (AJOL)

Carbaryl is a broad-spectrum insecticide used to control insect pests. In aquatic environments, it can disrupt the endocrine system and adversely affect the reproductive function of aquatic animals. This study investigated sublethal impacts of carbaryl on embryos and gonads of zebrafish Danio rerio in order to assess the ...

The sublethal effects of the organochlorines dieldrin and lindane on growth and reproduction of Eudrilus eugeniae and Eisenia fetida (Oligochaeta

Directory of Open Access Journals (Sweden)

Editorial Office

1994-07-01

Full Text Available Experimental exposure of the earthworm species Eudrilus eugeniae to organochlorines showed that dieldrin causes damage to sperm ultrastructure when viewed electronmicroscopically. Worms containing concentrations of 7,27 mg/kg dieldrin and higher showed more than 10% sperm damage. Exposure of Eisenia fetida to sublethal concentrations of lindane did not result in sperm damage but demonstrated an increase in growth and reproductive activity. It is argued that quantification of sperm damage and correlation with pesticide concentration could provide a useful tool for evaluating environmental quality. Furthermore, the effects of sublethal concentrations of pesticides that manifest themselves in increased growth and reproductive activity could affect ecological balances.

Larval Red Drum (Sciaenops ocellatus) Sublethal Exposure to Weathered Deepwater Horizon Crude Oil: Developmental and Transcriptomic Consequences.

Science.gov (United States)

Xu, Elvis Genbo; Khursigara, Alex J; Magnuson, Jason; Hazard, E Starr; Hardiman, Gary; Esbaugh, Andrew J; Roberts, Aaron P; Schlenk, Daniel

2017-09-05

The Deepwater Horizon (DWH) incident resulted in extensive oiling of the pelagic zone and shoreline habitats of many commercially important fish species. Exposure to the water-accommodated fraction (WAF) of oil from the spill causes developmental toxicity through cardiac defects in pelagic fish species. However, few studies have evaluated the effects of the oil on near-shore estuarine fish species such as red drum (Sciaenops ocellatus). Following exposure to a certified weathered slick oil (4.74 μg/L ∑PAH 50 ) from the DWH event, significant sublethal impacts were observed ranging from impaired nervous system development [average 17 and 22% reductions in brain and eye area at 48 h postfertilization (hpf), respectively] to abnormal cardiac morphology (100% incidence at 24, 48, and 72 hpf) in red drum larvae. Consistent with the phenotypic responses, significantly differentially expressed transcripts, enriched gene ontology, and altered functions and canonical pathways predicted adverse outcomes in nervous and cardiovascular systems, with more pronounced changes at later larval stages. Our study demonstrated that the WAF of weathered slick oil of DWH caused morphological abnormalities predicted by a suite of advanced bioinformatic tools in early developing red drum and also provided the basis for a better understanding of molecular mechanisms of crude oil toxicity in fish.

Acute toxicity and sublethal effects of gallic and pelargonic acids on the zebrafish Danio rerio.

Science.gov (United States)

Techer, Didier; Milla, Sylvain; Fontaine, Pascal; Viot, Sandrine; Thomas, Marielle

2015-04-01

Gallic and pelargonic acids are naturally found in a variety of plants and food products. Despite their extensive use in man-made applications, little is known regarding their potential risks to aquatic vertebrates. The aim of this work was to assess the acute toxicity of these polyphenolic and fatty acid compounds to the zebrafish. In order to get insights into sublethal effects, the enzyme activity of usual biomarkers related to oxidative stress and biotransformation were also assessed in fish. These latter included total superoxide dismutase, catalase as well as total glutathione peroxidase for antioxidant defence mechanisms and glutathione S-transferase for biotransformation related enzyme. Gallic acid was practically non-toxic (96-h lethal concentration (LC50) > 100 mg/L) whereas pelargonic acid was slightly toxic (96-h LC50 of 81.2 mg/L). Moreover, biomarker analyses indicated enhanced superoxide dismutase activity in fish exposed to 20, 40 and 100 mg/L of gallic acid compared to control. A dose-dependent induction of glutathione peroxidase and glutathione S-transferase was reported following gallic acid exposure at the tested concentrations of 10, 20 and 40 mg/L, with the exception of 100 mg/L of substance where basal activity levels were reported. In the case of pelargonic acid, there was no change in antioxidant enzyme activity while an inhibition of glutathione S-transferase was observed from organisms exposed to 45, 58 and 76 mg/L of test solution. The results concerning sublethal effects on biological parameters of zebrafish highlighted thereby the need for further investigations following chronic exposure to both organic acids.

Differential Gene Expression in Explanted Human Retinal Pigment Epithelial Cells 24-Hours Post-Exposure to 532 nm, 3.0 ns Pulsed Laser Light and 1064 nm, 170 ps Pulsed Laser Light 12-Hours Post-Exposure: Results Compendium

National Research Council Canada - National Science Library

Obringer, John

2004-01-01

.... We assessed the sublethal insult to human retinal pigment epithelial cells using a cadaver organ donor explant system for genes differentially expressed 12 and 24 hours post- exposure using gene...

Contact irritant responses of Aedes aegypti Using sublethal concentration and focal application of pyrethroid chemicals.

Science.gov (United States)

Manda, Hortance; Shah, Pankhil; Polsomboon, Suppaluck; Chareonviriyaphap, Theeraphap; Castro-Llanos, Fanny; Morrison, Amy; Burrus, Roxanne G; Grieco, John P; Achee, Nicole L

2013-01-01

Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. Contact irritancy (escape) behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru) using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC) of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin. Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR) resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at time of exit (by four hours) and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%. Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human-vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is currently unknown and will depend on rate of biting on human hosts prior to house exiting.

Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells.

Science.gov (United States)

Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

2015-10-01

Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. Copyright © 2015 Elsevier Inc. All rights reserved.

Chronic exposure to sublethal hexavalent chromium affects organ histopathology and serum cortisol profile of a teleost, Channa punctatus (Bloch)

International Nuclear Information System (INIS)

Mishra, Ashish K.; Mohanty, Banalata

2009-01-01

Effects of chronic exposures (one and two months) to sublethal doses of hexavalent chromium (2 and 4 mg/L potassium dichromate) on organ histopathology and serum cortisol profile were investigated and their overall impact on growth and behavior of a teleost fish, Channa punctatus was elucidated. Histopathological lesions were distinct in the vital organs gill, kidney and liver. The gill lamellae became lifted, fused, and showed oedema. Hyperplasia and hypertrophy of lamellar epithelial cells were distinct with desquamation. Hypertrophy of epithelial cells of renal tubules and reduction in tubular lumens were observed in the trunk kidney. The atrophy of the head kidney interrenal cells and decreased serum cortisol level indicated exhaustion of interrenal activity. Hepatocyte vacuolization and shrinkage, nuclear pyknosis and increase of sinusoidal spaces were observed in the liver. Abnormal behavioral patterns and reduced growth rate were also noticed in the exposed fish. The chronic hexavalent chromium exposure thus by affecting histopathology of gill, kidney (including interrenal tissue) and liver could impair the vital functions of respiration, excretion, metabolic regulation and maintenance of stress homeostasis which in the long-run may pose serious threat to fish health and affect their population.

Chronic exposure to sublethal hexavalent chromium affects organ histopathology and serum cortisol profile of a teleost, Channa punctatus (Bloch)

Energy Technology Data Exchange (ETDEWEB)

Mishra, Ashish K. [Department of Zoology, University of Allahabad, Allahabad-211002 (India); Mohanty, Banalata, E-mail: drbana_mohanty@rediffmail.com [Department of Zoology, University of Allahabad, Allahabad-211002 (India)

2009-09-01

Effects of chronic exposures (one and two months) to sublethal doses of hexavalent chromium (2 and 4 mg/L potassium dichromate) on organ histopathology and serum cortisol profile were investigated and their overall impact on growth and behavior of a teleost fish, Channa punctatus was elucidated. Histopathological lesions were distinct in the vital organs gill, kidney and liver. The gill lamellae became lifted, fused, and showed oedema. Hyperplasia and hypertrophy of lamellar epithelial cells were distinct with desquamation. Hypertrophy of epithelial cells of renal tubules and reduction in tubular lumens were observed in the trunk kidney. The atrophy of the head kidney interrenal cells and decreased serum cortisol level indicated exhaustion of interrenal activity. Hepatocyte vacuolization and shrinkage, nuclear pyknosis and increase of sinusoidal spaces were observed in the liver. Abnormal behavioral patterns and reduced growth rate were also noticed in the exposed fish. The chronic hexavalent chromium exposure thus by affecting histopathology of gill, kidney (including interrenal tissue) and liver could impair the vital functions of respiration, excretion, metabolic regulation and maintenance of stress homeostasis which in the long-run may pose serious threat to fish health and affect their population.

Investigation of ionizing sublethal doses effects on endogenous radioresistance background

International Nuclear Information System (INIS)

Kudryashov, Yu.B.; Goncharenko, E.N.; Antonova, S.V.; Akhalaya, M.Ya.; Bajzhumanov, A.A.; Shestakova, S.V.

1997-01-01

Sublethal doses of X-radiation (0.5 Gy and 1 Gy) caused the alterations in levels of main components of endogenous radioresistance background in rat tissues. There were demonstrated the decrease of serotonin content in stomach mocosa and spleen, adrenalin, noradrenalin and corticosteroids contents in adrenal glands, nonprotein thiols content in spleen and the increase of lipid peroxide level in serum on the 3-14 days after irradiation. The recovery of the investigated parameters was occurred to the 21 day after exposure. (author)

Effect of sublethal gamma radiation on host defenses in experimental scrub typhus

International Nuclear Information System (INIS)

Kelly, D.J.; Rees, J.C.

1986-01-01

The effect of sublethal gamma radiation on inbred mice chronically infected with scrub typhus rickettsiae was examined. Inbred mice which were inoculated with the Gilliam or Karp strain of Rickettsia tsutsugamushi by the subcutaneous route harbored the infection for at least 1 year. Irradiation of these animals at 12 or 52 weeks postinoculation with normally sublethal levels induced a significantly higher percentage of rickettsemic mice (recrudescence) than was seen in the unirradiated, similarly infected control animals. In addition, sublethal irradiation at 12 weeks induced a quantitative increase in total rickettsiae. Homologous antibody titers to the rickettsiae were examined for 5 weeks after irradiation to determine the role of the humoral response in radiation-induced recrudescence. Unirradiated, infected mice showed consistent titers of about 320 throughout the 5-week observation period, and the titer was not affected by exposure of up to 500 rads of gamma radiation. Drug dose-dependent radioprotection and modification of recrudescence was noted in infected, irradiated mice treated with the antiradiation compound S-2-(3-aminopropylamino)ethyl phosphorothioic acid. The results of this investigation supported the conclusion that the recrudescence of a chronic rickettsial infection in the appropriate host after immunological impairment due to gamma radiation can result in an acute, possibly lethal rickettsemia

Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida

NARCIS (Netherlands)

Rico, Andreu; Sabater, Consuelo; Castillo, María Ángeles

2016-01-01

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure

Sublethal effects of heavy metals on biochemical composition and their recovery in Indian major carps

International Nuclear Information System (INIS)

Garg, Smita; Gupta, R.K.; Jain, K.L.

2009-01-01

Studies were conducted to assess the effects of sublethal exposure of heavy metals cadmium, arsenic and zinc for 45 days on Indian major carps, Labeo rohita, Cirrhinus mrigala and Catla catla. Heavy metal treatments in general showed significant reduction in carbohydrate and lipid contents content in muscles as well as in gills in all the three fish species. The order of reduction of muscle and gill carbohydrate and lipid content due to different treatments was Cd + As + Zn > Cd + As > As + Zn > Cd + Zn > Cd > As > Zn. When fish were transferred to metal free water for 30 days, the level of carbohydrate and lipid contents improved considerably in all the three fish species

Development of Cardiovascular and Neurodevelopmental Metrics as Sublethal Endpoints for the Fish Embryo Toxicity Test.

Science.gov (United States)

Krzykwa, Julie C; Olivas, Alexis; Jeffries, Marlo K Sellin

2018-06-19

The fathead minnow fish embryo toxicity (FET) test has been proposed as a more humane alternative to current toxicity testing methods, as younger organisms are thought to experience less distress during toxicant exposure. However, the FET test protocol does not include endpoints that allow for the prediction of sublethal adverse outcomes, limiting its utility relative to other test types. Researchers have proposed the development of sublethal endpoints for the FET test to increase its utility. The present study 1) developed methods for previously unmeasured sublethal metrics in fathead minnows (i.e., spontaneous contraction frequency and heart rate) and 2) investigated the responsiveness of several sublethal endpoints related to growth (wet weight, length, and growth-related gene expression), neurodevelopment (spontaneous contraction frequency, and neurodevelopmental gene expression), and cardiovascular function and development (pericardial area, eye size and cardiovascular related gene expression) as additional FET test metrics using the model toxicant 3,4-dichloroaniline. Of the growth, neurological and cardiovascular endpoints measured, length, eye size and pericardial area were found to more responsive than the other endpoints, respectively. Future studies linking alterations in these endpoints to longer-term adverse impacts are needed to fully evaluate the predictive power of these metrics in chemical and whole effluent toxicity testing. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Histopathological effects of lethal and sub-lethal concentrations of ...

African Journals Online (AJOL)

The histopathological effects of lethal and sub-lethal concentrations of glyphosate on African catfish Clarias gariepinus were investigated. C. gariepinus juveniles were assessed in a static renewal bioassay for 96 hours (acute toxicity) and 28 days (chronic toxicity) using varying concentrations (0.0 mg/l 20.0 mg/l, 30.0 mg/l, ...

Assessment of acute sublethal effects of clothianidin on motor function of honeybee workers using video-tracking analysis.

Science.gov (United States)

Alkassab, Abdulrahim T; Kirchner, Wolfgang H

2018-01-01

Sublethal impacts of pesticides on the locomotor activity might occur to different degrees and could escape visual observation. Therefore, our objective is the utilization of video-tracking to quantify how the acute oral exposure to different doses (0.1-2ng/bee) of the neonicotinoid "clothianidin" influences the locomotor activity of honeybees in a time course experiment. The total distance moved, resting time as well as the duration and frequency of bouts of laying upside down are measured. Our results show that bees exposed to acute sublethal doses of clothianidin exhibit a significant increase in the total distance moved after 30 and 60min of the treatment at the highest dose (2ng/bee). Nevertheless, a reduction of the total distance is observed at this dose 90min post-treatment compared to the distance of the same group after 30min, where the treated bees show an arched abdomen and start to lose their postural control. The treated bees with 1ng clothianidin show a significant increase in total distance moved over the experimental period. Moreover, a reduction in the resting time and increase of the duration and frequency of bouts of laying upside down at these doses are found. Furthermore, significant effects on the tested parameters are observed at the dose (0.5ng/bee) first at 60min post-treatment compared to untreated bees. The lowest dose (0.1ng/bee) has non-significant effects on the motor activity of honeybees compared to untreated bees over the experimental period. Copyright © 2017 Elsevier Inc. All rights reserved.

Contact irritant responses of Aedes aegypti Using sublethal concentration and focal application of pyrethroid chemicals.

Directory of Open Access Journals (Sweden)

Hortance Manda

Full Text Available BACKGROUND: Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application. METHODS: Contact irritancy (escape behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin. RESULTS: Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at <100% SAC using ½FAR of all test compounds. In most trials, KD and 24 hour mortality rates were higher in mosquitoes that did not escape than in those that escaped. In Thailand, field validation studies indicated an early time of exit (by four hours and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%. CONCLUSIONS/SIGNIFICANCE: Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human-vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is

Gulf of Mexico offshore operations monitoring experiment (GOOMEX), Phase I: Sublethal responses to contaminant exposure - introduction and overview

International Nuclear Information System (INIS)

Kennicutt, M. C.; Montagna, P.; Roscigno, P. F.

1996-01-01

An overview of a three-phase study to evaluate the range of biological, biochemical and chemical methodologies to detect and assess chronic sublethal biological impacts in the vicinity of long-duration activities in the Gulf of Mexico associated with oil and gas exploration and production, was provided. The basic program comprises four activities stretching over a two-year period, and is designed to detect nearfield impacts and contaminant gradients extending out of each of three sites. Sampling design includes a radial pattern with stations at intervals up to 3000 meters distant from the platform. The design employs a dose-response model to test the hypothesis that biological, biochemical and chemical variations are due to platform-derived contaminants. Detailed analysis of the contaminants includes analysis of sediments, pore waters and biological tissue, and assessment of community health based on life history and reproduction studies. 57 refs., 9 tabs., 5 figs

Effects of Copper Exposure on Photosynthesis and Growth of the Seagrass Cymodocea nodosa: An Experimental Assessment.

Science.gov (United States)

Llagostera, Izaskun; Cervantes, Daniel; Sanmartí, Neus; Romero, Javier; Pérez, Marta

2016-09-01

Seagrasses form some of the most important coastal habitats. They may be negatively affected by trace metal contamination in certain coastal areas. In this study we experimentally assessed selected morphological and physiological traits of the seagrass Cymodocea nodosa, with increasing concentrations of copper (Cu) under controlled laboratory conditions. Short term (21 days) sub-lethal effects such as decreased maximum quantum yield, increased leaf necrosis and decreased shoot growth and shoot recruitment were clearly observed at the highest Cu exposure (5 mg L(-1)), while the effects were weaker at the intermediate concentration (2.5 mg L(-1)) and almost absent at the lowest concentration (1 mg L(-1)), indicating that this species is highly tolerant to copper exposure, at least in the short term. This fact could help to explain its distribution in relatively polluted coastal waters.

Relationship between sublethal injury and inactivation of yeast cells by the combination of sorbic acid and pulsed electric fields.

Science.gov (United States)

Somolinos, M; García, D; Condón, S; Mañas, P; Pagán, R

2007-06-01

The objective of this study was to investigate the occurrence of sublethal injury after the pulsed-electric-field (PEF) treatment of two yeasts, Dekkera bruxellensis and Saccharomyces cerevisiae, as well as the relation of sublethal injury to the inactivating effect of the combination of PEF and sorbic acid. PEF caused sublethal injury in both yeasts: more than 90% of surviving D. bruxellensis cells and 99% of surviving S. cerevisiae cells were sublethally injured after 50 pulses at 12 kV/cm in buffer at pHs of both 7.0 and 4.0. The proportion of sublethally injured cells reached a maximum after 50 pulses at 12.0 kV/cm (S. cerevisiae) or 16.5 kV/cm (D. bruxellensis), and it kept constant or progressively decreased at greater electric field strengths and with longer PEF treatments. Sublethally PEF-injured cells showed sensitivity to the presence of sorbic acid at a concentration of 2,000 ppm. A synergistic inactivating effect of the combination of PEF and sorbic acid was observed. Survivors of the PEF treatment were progressively inactivated in the presence of 2,000 ppm of sorbic acid at pH 3.8, with the combined treatments achieving more than log10 5 cycles of dead cells under the conditions investigated. This study has demonstrated the occurrence of sublethal injury after exposure to PEF, so yeast inactivation by PEF is not an all-or-nothing event. The combination of PEF and sorbic acid has proven to be an effective method to achieve a higher level of yeast inactivation. This work contributes to the knowledge of the mechanism of microbial inactivation by PEF, and it may be useful for improving food preservation by PEF technology.

Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

Science.gov (United States)

Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

2015-06-01

Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms. © 2015 SETAC.

Effect of exposure to sublethal concentrations of sodium cyanide on the carbohydrate metabolism of the Indian Major Carp Labeo rohita (Hamilton, 1822

Directory of Open Access Journals (Sweden)

Praveen N. Dube

2013-07-01

Full Text Available Experiments were designed to study in-vivo effects of sodium cyanide on biochemical endpoints in the freshwater fish Labeo rohita. Fish were exposed to two sublethal concentrations (0.106 and 0.064mg/L for a period of 15 days. Levels of glycogen, pyruvate, lactate and the enzymatic activities of lactate dehydrogenase (LDH, succinate dehydrogenase (SDH, glucose-6-phosphate dehydrogenase (G6PDH, phosphorylase, alkaline phosphatase (ALP, acid phosphatase (AcP were assessed in different tissues (liver, muscle and gills. Result indicated a steady decrease in glycogen, pyruvate, SDH, ALP and AcP activity with a concomitant increase in the lactate, phosphorylase, LDH and G6PD activity in all selected tissues. The alterations in all the above biochemical parameters were significantly (p<0.05 time and dose dependent. In all the above parameters, liver pointing out the intensity of cyanide intoxication compare to muscle and gills. Study revealed change in the metabolic energy by means of altered metabolic profile of the fish. Further, these observations indicated that even sublethal concentrations of sodium cyanide might not be fully devoid of deleterious influence on metabolism in L. rohita.

PAH-induced sublethal narcosis alters the bioenergetics and bioaccumulation of Fundulus heteroclitus

Energy Technology Data Exchange (ETDEWEB)

Merten, A. [NOAA Office of Response and Restoration, Hazardous Materials and Response, Seattle (United States); Beard, E.; Baker, B. [Univ. of Maryland, Solomons (United States)

2004-09-15

Accumulation of non-polar narcotic chemicals in organisms alters their metabolic rates and, therefore their energetic demands. Since exposure of these hydrophobic chemicals is primarily through the diet, we hypothesize that decreasing metabolic rates caused by accumulation of narcotics reduces feeding which, in turn, decreases further exposure to the narcotic. Thus, dietary exposure to and accumulation of narcotics may cause a negative feedback, reducing net bioaccumulation. The purpose of this short paper is to discuss the results of a long-term fish contaminant exposure study and to describe a fish bioenergetics model coupled to a PCBbioaccumulation model. The laboratory component consisted of exposing the estuarine fish Fundulus heteroclitus to environmentally-relevant levels of hydrophobic organic contaminants (HOCs) through their diet. We developed the model to further examine and understand the consequences of sublethal narcosis at both the individual and population levels of Fundulus heteroclitus.

The influence of insecticide exposure and environmental stimuli on the movement behaviour and dispersal of a freshwater isopod

NARCIS (Netherlands)

Augusiak, Jacqueline; Brink, van den Paul J.

2016-01-01

Behaviour links physiological function with ecological processes and can be very sensitive towards environmental stimuli and chemical exposure. As such, behavioural indicators of toxicity are well suited for assessing impacts of pesticides at sublethal concentrations found in the environment.

A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.

Science.gov (United States)

Charreton, Mercédès; Decourtye, Axel; Henry, Mickaël; Rodet, Guy; Sandoz, Jean-Christophe; Charnet, Pierre; Collet, Claude

2015-01-01

The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…), before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well. Our study focused on young bees (day 1 after emergence) since (i) few studies are available on locomotion at this stage and (ii) in recent years, pesticides have been reported to accumulate in different hive matrices, where young bees undergo their early development. At sublethal doses (SLD48h, i.e. causing no mortality at 48 h), three pyrethroids, namely cypermethrin (2.5 ng/bee), tetramethrin (70 ng/bee), tau-fluvalinate (33 ng/bee) and the neonicotinoid thiamethoxam (3.8 ng/bee) caused a locomotor deficit in honeybees. While the SLD48h of fipronil (a phenylpyrazole, 0.5 ng/bee) had no measurable effect on locomotion, we observed high mortality several days after exposure, an effect that was not observed with the other insecticides. Although locomotor deficits observed in the sublethal range of pyrethroids and thiamethoxam would suggest deleterious effects in the field, the case of

A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.

Directory of Open Access Journals (Sweden)

Mercédès Charreton

Full Text Available The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…, before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well. Our study focused on young bees (day 1 after emergence since (i few studies are available on locomotion at this stage and (ii in recent years, pesticides have been reported to accumulate in different hive matrices, where young bees undergo their early development. At sublethal doses (SLD48h, i.e. causing no mortality at 48 h, three pyrethroids, namely cypermethrin (2.5 ng/bee, tetramethrin (70 ng/bee, tau-fluvalinate (33 ng/bee and the neonicotinoid thiamethoxam (3.8 ng/bee caused a locomotor deficit in honeybees. While the SLD48h of fipronil (a phenylpyrazole, 0.5 ng/bee had no measurable effect on locomotion, we observed high mortality several days after exposure, an effect that was not observed with the other insecticides. Although locomotor deficits observed in the sublethal range of pyrethroids and thiamethoxam would suggest deleterious effects in the field

Assessing Sub-Lethal Impacts of Petroleum Compounds on Marine Benthic Systems

Energy Technology Data Exchange (ETDEWEB)

Lindgren, J. Fredrik

2012-07-01

with manually classified samples. Sufficient tax on diversity was used, allowing multivariate statistical analysis to reveal differences in the meiofauna communities between different depths. Dissimilarities were mostly owing to changes in salinity with increasing depth. The second part of the thesis is dedicated to evaluate effects of minor additions of a petroleum product with low concentrations of PAHs, a group of substances which can incur lethal and sub-lethal effects in biota. Here the common Swedish MK-1 diesel was used, which contains 370 times less PAHs than its European Union counterpart. Sediment meiofauna and microorganisms were incubated in microcosms for 60 days and exposed to diesel in different concentrations, 0.2, 2.0 and 20 times the background levels of PAHs in control sediment from the Gullmar Fjord. Meiofaunal community effects were evident after 30 and 60 days, with increasing differences, in treatments with 2.0 and 20 times the background levels of PAHs. Pronounced changes in inorganic fluxes were detected in the latter PAH treatments, resulting in lowered {Sigma}NOx, silicate and phosphate fluxes. The most sensitive endpoint, potential nitrification, was affected in the two highest concentrations after two days as well as in all treatments at day 30 and 60. This suggests an altered community of meiofauna with lowered activity and a microbial community with reduced inorganic flux recycling capabilities, effects that have the possibility of cascading upwards in the food web. The ecotoxicological endpoints included in this evaluation method, with the use of automatic classification of meiofauna, have shown to be strong tools in assessing effects of small scale discharges of petroleum products. This method can be used further to continue evaluating effects of other anthropogenic stressors, commonly ending up in these marine systems.

Sublethal Growth Effects and Mortality to Marine Bivalves and Fish from Long-Term Exposure to Tributyltin.

Science.gov (United States)

1985-07-01

sublethal toxicity of tributyltin oxide (TBTO) and its putative environmental product, tribu- tyltin sulfide ( TBTS ) to zoeal mud crabs, RIthropanopeus...Organotin .,’vwfuf coatingsu~~ study better defines the longterm toxicity and bloaccumnulation potential of tributyltin released from antifouting...larval fish survival at low tributyltin concentrations were also tested. Acute toxicity tests (96 hours) were con- ducted with mysid shrmp (Aawhomyot

Lethal and Sub-lethal Effects of Four Insecticides on the Aphidophagous Coccinellid Adalia bipunctata (Coleoptera: Coccinellidae).

Science.gov (United States)

Depalo, Laura; Lanzoni, Alberto; Masetti, Antonio; Pasqualini, Edison; Burgio, Giovanni

2017-12-05

Conventional insecticide assays, which measure the effects of insecticide exposure on short-term mortality, overlook important traits, including persistence of toxicity or sub-lethal effects. Therefore, such approaches are especially inadequate for prediction of the overall impact of insecticides on beneficial arthropods. In this study, the side effects of four modern insecticides (chlorantraniliprole, emamectin benzoate, spinosad, and spirotetramat) on Adalia bipunctata (L.) (Coleoptera: Coccinellidae) were evaluated under laboratory conditions by exposition on treated potted plants. In addition to investigation of acute toxicity and persistence of harmful activity in both larvae and adults of A. bipunctata, demographic parameters were evaluated, to provide a comprehensive picture of the nontarget effects of these products. Field doses of the four insecticides caused detrimental effects to A. bipunctata; but in different ways. Overall, spinosad showed the best toxicological profile among the products tested. Emamectin benzoate could be considered a low-risk insecticide, but had high persistence. Chlorantraniliprole exhibited lethal effects on early instar larvae and adults, along with a long-lasting activity, instead spirotetramat showed a low impact on larval and adult mortality and can be considered a short-lived insecticide. However, demographic analysis demonstrated that chlorantraniliprole and spirotetramat caused sub-lethal effects. Our findings highlight that sole assessment of mortality can lead to underestimation of the full impact of pesticides on nontarget insects. Demographic analysis was demonstrated to be a sensitive method for detection of the sub-lethal effects of insecticides on A. bipunctata, and this approach should be considered for evaluation of insecticide selectivity. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Quantifying sublethal effects of glyphosate and Roundup® to Daphnia magna using a fluorescence based enzyme activity assay and video tracking

DEFF Research Database (Denmark)

Roslev, Peter; R. Hansen, Lone; Ørsted, Michael

Glyphosate (N-(phosphonomethyl)glycine) is the active ingredient in a range of popular broad-spectrum, non-selective herbicide formulations. The toxicity of this herbicide to non-target aquatic organisms such as Daphnia magna is often evaluated using conventional toxicity assays that focus...... on endpoints such as immobility and mortality. In this study, we investigated sublethal effects of glyphosate and Roundup® to D. magna using video tracking for quantifying behavioral changes, and a novel fluorescence based assay for measuring in vivo hydrolytic enzyme activity (FLEA assay). Roundup® exposure...... resulted in concentration-dependent inhibition of alkaline phosphatase activity in D. magna. The inhibition of alkaline phosphatase by Roundup® was temperature-dependent with lowest inhibition at 14 °C and greater inhibition at 20 and 26 °C. Exposure of D. magna to sublethal concentrations of glyphosate...

Mechanistic Approach to Understanding the Toxicity of the Azole Fungicide Triadimefon to a Nontarget Aquatic Insect and Implications for Exposure Assessment

Science.gov (United States)

We utilized mechanistic and stereoselective based in vitro metabolism assays and sublethal exposures of triadimefon to gain insight into the extent of carbonyl reduction and the toxic mode of action of triadimefon with black fly (Diptera: Simuliidae) larvae.

Exposure to a widespread non-pathogenic bacterium magnifies sublethal pesticide effects in the damselfly Enallagma cyathigerum: From the suborganismal level to fitness-related traits

International Nuclear Information System (INIS)

Janssens, Lizanne; Stoks, Robby

2013-01-01

While there is increasing concern that pesticide stress can interact with stress imposed by antagonistic species including pathogens, it is unknown whether this also holds for non-pathogenic bacteria. We exposed Enallagma cyathigerum damselfly larvae to the pesticide chlorpyrifos and a non-pathogenic Escherichia coli strain. Both exposure to chlorpyrifos and E. coli reduced growth rate and fat storage, probably due to the observed energetically costly increases in physiological defence (glutathione-S-transferase and Hsp70) and, for E. coli, immune defence (phenoloxidase). Moreover, these stressors interacted for both fitness-related traits. Most importantly, another fitness-related trait, bacterial load, increased drastically with chlorpyrifos concentration. A possible explanation is that the upregulation of phenoloxidase in the presence of E. coli changed into a downregulation when combined with chlorpyrifos. We argue that the observed interactive, partly synergistic effects between pesticides and widespread non-pathogenic bacteria may be common and deserves further attention to improve ecological risk assessment of pesticides. -- Highlights: ► Non-pathogens such as the bacterium E. coli are ignored in ecotoxicology. ► Both E. coli and chlorpyrifos impaired fitness-related traits in damselfly larvae. ► E. coli modulated and magnified effects of chlorpyrifos on physiology and fitness. ► Bacterial load was magnified >10× in the presence of chlorpyrifos. ► Risk assessment of pesticides should consider synergisms with non-pathogens. -- Non-pathogenic bacteria reduce fitness-related traits and can synergistically interact with sublethal pesticide effects for physiological and fitness-related traits

Transmission electron microscopy study of Listeria monocytogenes serotype 1/2a cells exposed to sublethal heat stress and carvacrol

Science.gov (United States)

The objective of this study was to investigate the morphological changes that occurred in Listeria monocytogenes serotype 1/2a cells as visualized by transmission electron microscopy (TEM) after exposure to sublethal heat stress at 48°C for 60 min and in combination with lethal concentration of carv...

Deterioration in brain and heart functions following a single sub-lethal (0.8 LCt50) inhalation exposure of rats to sarin vapor:

International Nuclear Information System (INIS)

Allon, N.; Chapman, S.; Egoz, I.; Rabinovitz, I.; Kapon, J.; Weissman, B.A.; Yacov, G.; Bloch-Shilderman, E.; Grauer, E.

2011-01-01

The main injuries among victims of the terrorist act in the Tokyo subway resulted from sub-lethal inhalation and whole body exposure to sarin vapor. In order to study the long term effects of such exposure and to simulate these conditions, freely moving rats were exposed to sarin vapor (27.2 ± 1.7 μg/l) for 10 min. About 50% of the rats showed no overt symptoms and the rest had mild to moderate clinical symptoms that subsided within 4 h following exposure. A reduction of weight was noted during the first 3 days with full recovery on the 4th day. Rat's heart was challenged with epinephrine 1 and 6 months post exposure. A significant reduction in the threshold for epinephrine-induced arrhythmia (EPIA) was noted in rats exposed to sarin. A time dependent increase in the kD and Bmax values of muscarinic auto receptors (M2) was recorded in the rat's cortex and striatum. No changes were recorded in the rats' brain trans locator protein (TSPO) levels, concomitant with no observed changes in the animals' performance in A Morris water maze test. A significant increase in open field activity was noted 6 months following exposure to sarin vapor as well as a significant decrease in prostaglandin E 2 (PGE 2 ) production in the brain. It is speculated that down regulation of the M2 auto receptor function, caused hyper reactivity of the cholinergic system which leads to the changes described above. The continuous reduction in M2 auto-receptor system through an unknown mechanism may be the cause for long lasting decline in sarin-exposed casualties' health.

Low-salinity stress in the American lobster, Homarus americanus, after chronic sublethal exposure to cadmium: Biochemical effects

Energy Technology Data Exchange (ETDEWEB)

Gould, E

1980-01-01

Lobsters (Homarus americanus) were exposed to cadmium (6 ..mu..g 1sup(-1), 30 days) in flowing seawater, then held for 7 days in aerated 'clean' seawater at either ambient (27 per mill) or low (17 per mill) salinity. Cadmium exposure alone (ambient salinity) induced a general elevation of enzyme activity (heart, antennal gland, and muscle MDH; heart LDH and GPI), despite the probability of some clearance of cadmium from body tissues during the 'clean' seawater holding period. Low-salinity alone (non-exposed lobsters) caused a decrease of enzyme activity (AAT, LDH, GPI, PK) in most tissues examined, except for tail muscle IDH, the activity of which was increased, and MDH, which was significantly elevated above ambient controls in all tissues except heart. Most low-salinity effects were observed in tail muscle, and most cadmium effects, in heart; low-salinity effects outnumbered cadmium stress by nine to four. In heart and tail muscle of cadmium-exposed lobsters held at low salinity, each of the two stresses apparently operated to nullify the other's effects. The most prominent single biochemical response to these sublethal stresses was the elevation of MDH activity. The ratio MDH:LDH gave the clearest indication of overall relative stress.

Effects of acute sublethal gamma radiation exposure on aggressive behavior in male mice: A dose-response study

International Nuclear Information System (INIS)

Maier, D.M.; Landauer, M.R.

1989-01-01

The resident-intruder paradigm was used to assess the effects of gamma radiation (0, 3, 5, 7 Gray [Gy] cobalt-60) on aggressive offensive behavior in resident male mice over a 3-month period. The defensive behavior of nonirradiated intruder mice was also monitored. A dose of 3 Gy had no effect on either the residents' offensive behavior or the defensive behavior of the intruders paired with them. Doses of 5 and 7 Gy produced decreases in offensive behavior of irradiated residents during the second week postirradiation. The nonirradiated intruders paired with these animals displayed decreases in defensive behavior during this time period, indicating a sensitivity to changes in the residents' behavior. After the third week postirradiation, offensive and defensive behavior did not differ significantly between irradiated mice and sham-irradiated controls. This study suggests that sublethal doses of radiation can temporarily suppress aggressive behavior but have no apparent permanent effect on that behavior

Biochemical and Hematological Profiles of Common Carp (Cyprinus Carpio under Sublethal Effects of Trivalent Chromium

Directory of Open Access Journals (Sweden)

Zeynab Abedi

2016-07-01

Full Text Available Background: In natural waters and/or aquaculture facilities, fish are often exposed to chromium waste and demonstrate cumulative deleterious effects. To our knowledge, there are no studies concerning the effects of trivalent Cr on C. carpio hematology. This study presents hematological and some biochemical parameters of common carp, Cyprinus carpio, affected by sublethal concentration of trivalent chromium. Methods: The fish in the experimental aquaria (three replicates each were exposed to a sublethal chromium chloride concentration of 2 mg L−1, which was prepared as stock solution and added depending on the volume of the aquaria to obtain the required concentration. After a period of 28 days, parameters such as hematocrit (Hct, hemoglobin (Hb, lymphocytes (Lym, neutrophils (Neu, total protein (TP, albumin, immunoglobulin M (IgM, glucose, red and white blood cells (RBC and WBC, mean corpuscular volume (MCV, mean corpuscular hemoglobin (MCH, and mean corpuscular hemoglobin concentration (MCHC were examined. Results: Chromium exposure for 28 days significantly (P0.05 between the Cr-exposed fish and the control. Conclusion: Hematological indices of fish, caused by chromium toxicity to C. carpio, can be secondary responses to toxicants, including exposure to low concentrations of heavy metals, which reflect the launch of stress reaction in the affected fish.

Notochord in Tilapia nilotica Exposed to Sublethal Dose of Malathion, S[1, 2-Di(EthoxycarbonylEthyl] Dimethyl Phosphorothiolothionate

Directory of Open Access Journals (Sweden)

Edna Amparado

1992-06-01

Full Text Available Exposure of Tilapia nilotica embryos to sublethal dose of 1.0 ppm commercial grade malathion, S[1,2-di(ethoxycarbonylethyl] dimethyl phosphorothiolothionate from day-10 post fertilization resulted in notochordal aberrations. Pesticide-treated fishes exhibited constriction of the notochordal sheath, folding at the posterior sections and larger notochord than those of the control group.

PFOS, PFNA, and PFOA sub-lethal exposure to embryonic zebrafish have different toxicity profiles in terms of morphometrics, behavior and gene expression.

Science.gov (United States)

Jantzen, Carrie E; Annunziato, Kate A; Bugel, Sean M; Cooper, Keith R

2016-06-01

Polyfluorinated compounds (PFC) are a class of anthropogenic, persistent and toxic chemicals. PFCs are detected worldwide and consist of fluorinated carbon chains of varying length, terminal groups, and industrial uses. Previous zebrafish studies in the literature as well as our own studies have shown that exposure to these chemicals at a low range of concentrations (0.02-2.0μM; 20-2000ppb) resulted in chemical specific developmental defects and reduced post hatch survival. It was hypothesized that sub-lethal embryonic exposure to perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), or perfluorooctanoic acid (PFOA) would result in different responses with regard to morphometric, behavior, and gene expression in both yolk sac fry and larval zebrafish. Zebrafish were exposed to PFOS, PFOA, and PFNA (0.02, 0.2, 2.0μM) for the first five days post fertilization (dpf) and analyzed for morphometrics (5 dpf, 14 dpf), targeted gene expression (5 dpf, 14 dpf), and locomotive behavior (14 dpf). All three PFCs commonly resulted in a decrease in total body length, increased tfc3a (muscle development) expression and decreased ap1s (protein transport) expression at 5dpf, and hyperactive locomotor activity 14 dpf. All other endpoints measured at both life-stage time points varied between each of the PFCs. PFOS, PFNA, and PFOA exposure resulted in significantly altered responses in terms of morphometric, locomotion, and gene expression endpoints, which could be manifested in field exposed teleosts. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of sublethal exposure of Cartap on hypothalamo-neurosecretory system of the freshwater spotted murrel, Channa punctatus (Bloch).

Science.gov (United States)

Mishra, D K; Bohidar, K; Pandey, A K

2008-11-01

In order to record the effect of carbamate pesticide on hypothalamus of Channa punctatus, fish were exposed to sublethal concentration (0.18 mg l(-1), 30% LC50 for 96 hr) of Cartap for 24, 48, 72 and 96 hr under static bioassay condition. Hypothalamo-neurosecretory complex of the murrel consisted mainly of nucleus preopticus (NPO), nucleus lateralis tuberis (NLT) and their axonal tracts. NPO is a paired structure situtated on either side of the third ventricle anterodorsal to the optic chiasma and looked inverted L-shape in the sagittal section. NPO is morphologically divisible into a dorsal pars magnocellularis (PMC) consisting of large neurons and ventral pars parvocellularis (PPC) formed of smaller neurosecretory cells. NLT cells are distributed in the infundibular floor adjacent to the pituitary stalk. Sublethal Cartap treatment induced an initial hypertrophy of the neurosecretory cells of NPO and NLT followed by loss of staining affinity as well as varying degrees of cytoplasmic vacuolization and necrosis. Herring bodies (HB) were also encountered in the neurohypophysis of the treated fishes.

The influence of insecticide exposure and environmental stimuli on the movement behaviour and dispersal of a freshwater isopod.

Science.gov (United States)

Augusiak, Jacqueline; Van den Brink, Paul J

2016-09-01

Behaviour links physiological function with ecological processes and can be very sensitive towards environmental stimuli and chemical exposure. As such, behavioural indicators of toxicity are well suited for assessing impacts of pesticides at sublethal concentrations found in the environment. Recent developments in video-tracking technologies offer the possibility of quantifying behavioural patterns, particularly locomotion, which in general has not been studied and understood very well for aquatic macroinvertebrates to date. In this study, we aim to determine the potential effects of exposure to two neurotoxic pesticides with different modes of action at different concentrations (chlorpyrifos and imidacloprid) on the locomotion behaviour of the water louse Asellus aquaticus. We compare the effects of the different exposure regimes on the behaviour of Asellus with the effects that the presence of food and shelter exhibit to estimate the ecological relevance of behavioural changes. We found that sublethal pesticide exposure reduced dispersal distances compared to controls, whereby exposure to chlorpyrifos affected not only animal activity but also step lengths while imidacloprid only slightly affected step lengths. The presence of natural cues such as food or shelter induced only minor changes in behaviour, which hardly translated to changes in dispersal potential. These findings illustrate that behaviour can serve as a sensitive endpoint in toxicity assessments. However, under natural conditions, depending on the exposure concentration, the actual impacts might be outweighed by environmental conditions that an organism is subjected to. It is, therefore, of importance that the assessment of toxicity on behaviour is done under relevant environmental conditions.

Lethal and sublethal effects of pesticides in the management of Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) on Capsicum annuum L.

Science.gov (United States)

Breda, Mariana O; Oliveira, José V; Esteves Filho, Alberto B; Barbosa, Douglas Rs; Santos, Andrezo A

2017-10-01

The evaluation of lethal and sublethal effects is of great importance for a complete assessment of the total impact of chemical compounds upon pest populations and the development of management strategies. In this study, we evaluated the lethal and sublethal effects of different synthetic and botanical products on the broad mite Polyphagotarsonemus latus (Banks), a major pest of Capsicum annuum L. and other crops. Abamectin had the highest lethal effect on P. latus, followed by spiromesifen, azadirachtin, neem oil and nitrogen fertiliser + citric acid. The sublethal effects of the products were indicated by the influence on mite population growth, affecting the numbers of females, males, larvae, pupae and eggs. Furthermore, a negative instantaneous rate of increase in P. latus and repellent effects were observed. The lethal and sublethal effects of abamectin, spiromesifen, azadirachtin and neem oil significantly affect P. latus population growth, as well as causing repellence to this mite on C. annuum, and they should be considered in the integrated pest management of this mite. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Integrated Environmental Assessment Part III: ExposureAssessment

Energy Technology Data Exchange (ETDEWEB)

McKone, Thomas E.; Small, Mitchell J.

2006-06-01

Human exposure assessment is a key step in estimating the environmental and public health burdens that result chemical emissions in the life cycle of an industrial product or service. This column presents the third in a series of overviews of the state of the art in integrated environmental assessment - earlier columns described emissions estimation (Frey and Small, 2003) and fate and transport modeling (Ramaswami, et al., 2004). When combined, these first two assessment elements provide estimates of ambient concentrations in the environment. Here we discuss how both models and measurements are used to translate ambient concentrations into metrics of human and ecological exposure, the necessary precursors to impact assessment. Exposure assessment is the process of measuring and/or modeling the magnitude, frequency and duration of contact between a potentially harmful agent and a target population, including the size and characteristics of that population (IPCS, 2001; Zartarian, et al., 2005). Ideally the exposure assessment process should characterize the sources, routes, pathways, and uncertainties in the assessment. Route of exposure refers to the way that an agent enters the receptor during an exposure event. Humans contact pollutants through three routes--inhalation, ingestion, and dermal uptake. Inhalation occurs in both outdoor environments and indoor environments where most people spend the majority of their time. Ingestion includes both water and food, as well as soil and dust uptake due to hand-to-mouth activity. Dermal uptake occurs through contacts with consumer products; indoor and outdoor surfaces; the water supply during washing or bathing; ambient surface waters during swimming or boating; soil during activities such as work, gardening, and play; and, to a lesser extent, from the air that surrounds us. An exposure pathway is the course that a pollutant takes from an ambient environmental medium (air, soil, water, biota, etc), to an exposure medium

Assessment of sublethal endpoints after chronic exposure of the nematode Caenorhabditis elegans to palladium, platinum and rhodium.

Science.gov (United States)

Schertzinger, Gerhard; Zimmermann, Sonja; Grabner, Daniel; Sures, Bernd

2017-11-01

The aim of this study was to investigate chronic effects of the platinum-group elements (PGE) palladium (Pd), platinum (Pt) and rhodium (Rh) on the nematode Caenorhabditis elegans. Aquatic toxicity testing was carried out according to ISO 10872 by determining 96 h EC 50 values for sublethal endpoints, including growth, fertility and reproduction. Single PGE standard solutions were used as metal source. Based on the EC 50 values for Pt, reproduction (96 h EC 50  = 497 μg/L) was the most sensitive endpoint followed by fertility (96 h EC 50  = 726 μg/L) and growth (96 h EC 50  = 808 μg/L). For Pd, no precise EC 50 values could be calculated due to bell-shaped concentration response curves, but the 96 h EC 50 for reproduction ranged between 10 and 100 μg/L. Pd and Pt had effects on all endpoints. With raising element concentrations reproduction was inhibited first. At a certain concentration, fertility was also affected, which in turn had an additional effect on reproduction. Growth inhibition can also lead to a loss of fertility if the worms do not reach an appropriate body size to become fertile. Rhodium showed no inhibition of any endpoint between concentrations of 100 to 10,000 μg Rh/L. The results of this study allow the following order of PGE with respect to decreasing toxicity to C. elegans: Pd > Pt » Rh. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of human exposures

Energy Technology Data Exchange (ETDEWEB)

Lebret, E. [RIVM-National Inst. of Public Health and Environmental Protection (Netherlands)

1995-12-31

This article describes some of the features of the assessment of human exposure to environmental pollutants in epidemiological studies. Since exposure assessment in air pollution epidemiology studies typically involve professionals from various backgrounds, interpretation of a concepts like `exposure` may vary. A brief descriptions is therefore given by way of introduction

Assessment of human exposures

Energy Technology Data Exchange (ETDEWEB)

Lebret, E [RIVM-National Inst. of Public Health and Environmental Protection (Netherlands)

1996-12-31

This article describes some of the features of the assessment of human exposure to environmental pollutants in epidemiological studies. Since exposure assessment in air pollution epidemiology studies typically involve professionals from various backgrounds, interpretation of a concepts like `exposure` may vary. A brief descriptions is therefore given by way of introduction

Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum.

Science.gov (United States)

Amaradasa, B Sajeewa; Everhart, Sydney E

2016-01-01

Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor), iprodione (unclear mode of action), thiophanate methyl (inhibition of microtubulin synthesis) and azoxystrobin and pyraclostrobin (quinone outside inhibitors). Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50-100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR) loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs). SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each). Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed) generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA) and discriminant analysis of principal components (DAPC) identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001). Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the experiment, and

Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum.

Directory of Open Access Journals (Sweden)

B Sajeewa Amaradasa

Full Text Available Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor, iprodione (unclear mode of action, thiophanate methyl (inhibition of microtubulin synthesis and azoxystrobin and pyraclostrobin (quinone outside inhibitors. Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50-100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs. SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each. Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA and discriminant analysis of principal components (DAPC identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001. Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the

Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum

Science.gov (United States)

Amaradasa, B. Sajeewa

2016-01-01

Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor), iprodione (unclear mode of action), thiophanate methyl (inhibition of microtubulin synthesis) and azoxystrobin and pyraclostrobin (quinone outside inhibitors). Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50–100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR) loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs). SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each). Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed) generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA) and discriminant analysis of principal components (DAPC) identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001). Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the experiment

The suppressive effect of etoposide on recovery from sublethal radiation damage in Chinese hamster V 79 cells

International Nuclear Information System (INIS)

Saito, Tsutomu; Shimada, Yuji; Kawamori, Jiro; Kamata, Rikisaburo

1992-01-01

The combined effect of radiation and etoposide on the survival of cultured Chinese hamster V 79 cells was investigated. Cells in exponential growth phase were treated with various combinations of radiation and etoposide. The surviving fraction was assessed by colony formation. Etoposide significantly reduced so-called shoulder width, as expressed in Dq (quasithreshold dose), of radiation survival curves. The reduction depended on the increase of etoposide concentrations, although steepening of slopes of exponentially regressing portions of the radiation survival curves was slight. Split dose experiments showed that cells did not recover from sublethal radiation damage in the presence of low concentration of etoposide, although they did recover from sublethal radiation damage under a drug free condition. The results show the suppressive effect of etoposide on recovery from sublethal radiation damage. The effect of a sequential combination of radiation and etoposide was also investigated. The effect was more marked when the interval between radiation and etoposide was shorter regardless of the sequence. (author)

Sublethal effects of the Exxon Valdez oil spill on herring embryos and larvae: morphological, cytogenetic; and histopathological assessments, 1989-1991

International Nuclear Information System (INIS)

Hose, J. E.; Marty, G. D.; Hinton, D. E.

1996-01-01

Extensive sublethal damage assessments were carried out on Pacific herring larvae following the Exxon Valdez oil spill. Egg masses were collected from oiled and non-oiled areas during 1989 to 1991, and incubated to hatch. The hatched larvae were evaluated for morphological deformities, cytogenetic abnormalities, and histopathological lesions. In 1989, herring larvae from the oiled areas showed high incidence of morphological deformities and cytogenetic abnormalities compared to larvae from non-oiled areas. There was no evidence of histopathological lesions. Identical assessments in 1990 and 1991 revealed no detectable oil-related developmental and genetic effects. In contrast, there was a marked decrease in survival, suggesting that that genetic damage at heavily oiled stations combined with severe morphological malformations mitigated against survival through the stressful larval period. 40 refs., 1 tab.,8 figs

Intersex and liver alterations induced by long-term sublethal exposure to 17α-ethinylestradiol in adult male Cnesterodon decemmaculatus (Pisces: Poeciliidae).

Science.gov (United States)

Young, Brian Jonathan; López, Gabriela Carina; Cristos, Diego Sebastián; Crespo, Diana Cristina; Somoza, Gustavo Manuel; Carriquiriborde, Pedro

2017-07-01

The aim of the present study was to assess the responses of the gonopodium morphology and the gonadal and liver histology of adult male Cnesterodon decemmaculatus to sublethal long-term exposure concentrations of 17α-ethinylestradiol (EE2). Two experiments were conducted exposing the fish to waterborne concentrations of EE2 ranging from 20 ng/L to 200 ng/L for 8 wk, 12 wk, and 16 wk. Intersex gonads were observed after 8 wk and 16 wk in fish exposed to 200 ng EE2/L and 100 ng EE2/L, respectively. Oocytes' development from testis germ cells and replacement of the efferent duct periodic acid-Schiff-positive secretion surrounding spermatozeugmata by parenchymal tissue and duct structure alterations were the major observed changes in the gonads. In contrast, no response was observed in the gonopodium morphology. Liver histology was also altered, showing increasing steatosis, single-cell necrosis to generalized necrosis, and disruption of acinar organization from 100 ng EE2/L to 200 ng EE2/L. In summary, the present results showed that although EE2 was not able to alter the morphology of a developed gonopodium, it was capable of inducing development of testicular oocytes in adult male C. decemmaculatus at environmentally relevant concentrations. Thus, externally normal but intersex C. decemmaculatus males would be expected in the wastewater-receiving streams that the species inhabits. According to the literature, the present study would be the first indicating estrogen-induced intersex in adult male poeciliid. Environ Toxicol Chem 2017;36:1738-1745. © 2016 SETAC. © 2016 SETAC.

Response of sublethally irradiated monkeys to a replicating viral antigen

International Nuclear Information System (INIS)

Hilmas, D.E.; Spertzel, R.O.

1975-01-01

Temporal effects of exposure to sublethal, total-body x radiation (400 R) on responses to vaccination with the attenuated Venezuelan equine encephalomyelitis vaccine virus, TC-83, were examined in rhesus monkeys. Viremia, often with delayed onset, was prolonged even when irradiation preceded vaccination by 28 days. Virus titers were increased, particularly in groups irradiated 4 or 7 days before vaccination. Delay in appearance of hemagglutination-inhibition and serum-neutralizing antibody correlated closely with persistence of viremia in irradiated-vaccinated monkeys. The temporal course of antibody response was markedly affected by the interval between irradiation and injection of this replicating antigen. With longer intervals between irradiation and vaccination, the somewhat depressed antibody responses approached normal or surpassed those of nonirradiated monkeys. Vaccination 14 days after radiation exposure resulted in lethality to 8 of 12 monkeys, apparently as a result of secondary infection. The additional lymphopenic stress due to the effect of TC-83, superimposed on the severely depressed hematopoietic competence at 14 days, undoubtedly contributed to this increased susceptibility to latent infection

Importance of dose metrics for lethal and sublethal sediment metal toxicity in the oligochaete worm Lumbriculus variegatus

Energy Technology Data Exchange (ETDEWEB)

Penttinen, O.P.; Kilpi-Koski, J.; Toivainen, K. [Helsinki Univ., Lahti (Finland). Dept. of Ecology end Environmental Sciences; Jokela, M. [Mikkeli Univ. of Applied Sciences, Mikkeli (Finland); Vaeisaenen, A. [Jyvaeskylae Univ. (Finland). Dept. of Chemistry

2008-02-15

Background, aims, and scope. There is an increasing demand for controlled toxicity tests to predict biological effects related to sediment metal contamination. In this context, questions of metal-specific factors, sensitivity of toxicity endpoints, and variability in exposure duration arise. In addition, the choice of the dose metrics for responses is equally important and is related to the applicability of the concept of critical body residue (CBR) in exposure assessments, as well as being the main focus of this study. Methods. Experiments were conducted to assess toxicity of Cd, Cr, Cu and Pb to the oligochaete worm Lumbriculus variegatus with the aim of determining CBRs for two response metrics. Mortality and feeding activity of worms exposed to sediment-spiked metals were used as end-points in connection with residue analyses from both the organisms and the surrounding media. Results. LC50 values were 0.3, 1.4, 5.2, and 6.7 mg/L (from 4.7 {mu}mol/L to 128.0 {mu}mol/L), and the order of toxicity, from most toxic to least toxic, was Cu > Cd > Pb>Cr. By relating toxicity to body residue, variability in toxicity among the metals decreased and the order of toxicity was altered. The highest lethal residue value was obtained for Cu (10.8 mmol/kg) and the lowest was obtained for Cd (2.3 mmol/kg). In the 10-d sublethal test, both time and metal exposure were an important source of variation in the feeding activity of worms. The significant treatment effects were observed from worms exposed to Cd or Pb, with the controls yielding the highest feeding rate. However, quantitative changes in the measured end-point did not correlate with the exposure concentrations or body residues, which remained an order of magnitude lower than in the acute exposures. (orig.)

Migration of bone marrow cells to the thymus in sublethally irradiated mice

International Nuclear Information System (INIS)

Varlet, Andree; Lenaerts, Patrick; Houben-Defresne, M.P.; Boniver, Jacques

1982-01-01

In sublethally irradiated mice, thymus repopulation is due first to the proliferation of surviving thymocytes followed by the multiplication of bone marrow derived prothymocytes. The migration of bone marrow cells to the thymus after a single sublethal whole-body X irradiation was studied by using fluorescein isothiocyanate as a cell marker. Irradiation increases the permissiveness of the thymus to the immigration of bone marrow cells. Furthermore, the post-Rx regenerating bone marrow cells exhibit migration capacities greater than the normal ones. The radiation induced changes in the bone marrow thymus interaction might play an important role in thymus regeneration after sublethal irradiation [fr

Lethal and sublethal cellular injury in multifraction irradiation

International Nuclear Information System (INIS)

Withers, H.R.

1975-01-01

Work has been carried out on cellular injury in multifraction irradiation of mouse tissues and compared with similar work on human skin reported earlier by Dutreix et al (Eur. J. Cancer.; 9:159 (1973)). In agreement with Dutreix et al it is emphasized that the absolute amount of sublethal injury repaired per fractionation interval (Dsub(r)) is not as important to radiotherapists as the change in the amount repaired (ΔDsub(r)) when the dose-per-fraction is altered. It was found that although there is a critical divergence at low doses, the data for mouse tissues are similar to those previously given for human skin and support the conclusions: (i) That the capacity of many normal cells for accumulating and repairing sublethal radiation injury is probably not greatly different. (ii) That fixed exponents used for fraction number and time in iso-effect formulae are inaproporiate. At low doses-per-fraction, repair of sublethal injury is complete, or nearly so, and hence, additional fractionation of dose does not give appreciable additional sparing, whereas rapidly-regenerating tissues, due to the lengthening of overall time, would continue being spared by repopulation. (U.K.)

Sublethal microcystin exposure and biochemical outcomes among hemodialysis patients.

Directory of Open Access Journals (Sweden)

Elizabeth D Hilborn

Full Text Available Cyanobacteria are commonly-occurring contaminants of surface waters worldwide. Microcystins, potent hepatotoxins, are among the best characterized cyanotoxins. During November, 2001, a group of 44 hemodialysis patients were exposed to microcystins via contaminated dialysate. Serum microcystin concentrations were quantified with enzyme-linked immunosorbent assay which measures free serum microcystin LR equivalents (ME. We describe serum ME concentrations and biochemical outcomes among a subset of patients during 8 weeks following exposure. Thirteen patients were included; 6 were males, patients' median age was 45 years (range 16-80, one was seropositive for hepatitis B surface antigen. The median serum ME concentration was 0.33 ng/mL (range: <0.16-0.96. One hundred thirty nine blood samples were collected following exposure. Patients' biochemical outcomes varied, but overall indicated a mixed liver injury. Linear regression evaluated each patient's weekly mean biochemical outcome with their maximum serum ME concentration; a measure of the extrinsic pathway of clotting function, prothrombin time, was negatively and significantly associated with serum ME concentrations. This group of exposed patients' biochemical outcomes display evidence of a mixed liver injury temporally associated with microcystin exposure. Interpretation of biochemical outcomes are complicated by the study population's underlying chronic disease status. It is clear that dialysis patients are a distinct 'at risk' group for cyanotoxin exposures due to direct intravenous exposure to dialysate prepared from surface drinking water supplies. Careful monitoring and treatment of water supplies used to prepare dialysate is required to prevent future cyanotoxin exposure events.

RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera

Science.gov (United States)

Schneider, Christof W.; Tautz, Jürgen; Grünewald, Bernd; Fuchs, Stefan

2012-01-01

The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15–6 ng/bee) and clothianidin (0.05–2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin) and ≥1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further information on

RFID tracking of sublethal effects of two neonicotinoid insecticides on the foraging behavior of Apis mellifera.

Directory of Open Access Journals (Sweden)

Christof W Schneider

Full Text Available The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15-6 ng/bee and clothianidin (0.05-2 ng/bee under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin and ≥1.5 ng/bee (imidacloprid during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further

Repair of sublethal damage in mammalian cells irradiated at ultrahigh dose rates

International Nuclear Information System (INIS)

Gerweck, L.E.; Epp, E.R.; Michaels, H.B.; Ling, C.C.; Peterson, E.C.

1979-01-01

The lethal response of asynchronous Chinese hamster ovary (CHO) cells exposed to single and split doses of radiation at conventional or ultrahigh dose rates has been examined to determine whether repair of sublethal damage occurs in cells irradiated at ultrahigh dose rates. The high-intensity irradiations were performed with electrons delivered in single 3-nsec pulses from a 600-kV field emission source under medium-removed, thin-layer conditions. Conventional dose-rate experiments were done under identical thin-layer conditions with 50-kVp x rays, or under full-medium conditions with 280-kVp x rays. Oxygenated cells were irradiated and maintained at 22 to 24 0 C between exposures. Survival did not increase as the time between two doses of pulsed electrons increased from 0 to 4 min, indicating no evidence of fast repair. However, increased survival was observed when 30 to 90 min was allowed to elapse between the split doses. The half-time for maximum repair was approx. = 30 min irrespective of the exposure conditions and radiation modality used. Observed repair ratios increased from approx. = 2 to 4 as the single-dose surviving fraction decreased from 10 -2 to 5 x 10 -4 . Over this survival range the repair ratios, measured at the same value of surviving fraction, were independent of dose rate. The observed repair ratios imply that the shoulder regions of the nonfractionated x-ray and pulsed-electron survival curves were not completely restored between the split doses. However, the fraction of the shoulder restored between split doses of radiation was dose-rate-independent. It is concluded that sublethal damage can be repaired in oxygenated CHO cells irradiated at dose rates of the order of 10 11 rad/sec

Lethal and sublethal effects of azadirachtin and cypermethrin on Habrobracon hebetor (Hymenoptera: Braconidae).

Science.gov (United States)

Abedi, Zahra; Saber, Moosa; Gharekhani, Gholamhossein; Mehrvar, Ali; Kamita, Shizuo George

2014-04-01

Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC50) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 microg a.i./ml, respectively. The LC50 of cypermethrin was 5.4 microg a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a field recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r(m)) were affected negatively. The r(m) values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. Semifield and field studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.

Sub-lethal cadmium exposure increases phytochelatin concentrations in the aquatic snail Lymnaea stagnalis

Energy Technology Data Exchange (ETDEWEB)

SF, Gonçalves [Department of Biology & CESAM, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro (Portugal); SK, Davies [Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom); Bennett, M. [Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom); Raab, A.; Feldmann, J. [TESLA, Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland (United Kingdom); Kille, P. [Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3US (United Kingdom); Loureiro, S. [Department of Biology & CESAM, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro (Portugal); DJ, Spurgeon [Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford OX10 8BB (United Kingdom); JG, Bundy, E-mail: j.bundy@imperial.ac.uk [Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom)

2016-10-15

Phytochelatins are metal-binding metabolites found in almost all plant species and some animal groups, including nematodes and annelids, where they can play an important role in detoxifying metals such as cadmium. Species from several other taxa contain a phytochelatin synthase (PCS) gene orthologue, including molluscs, indicating they may have the potential to synthesize phytochelatins. However, the presence of a gene alone does not demonstrate that it plays a functional role in metal detoxification. In the present study, we show that the aquatic snail Lymnaea stagnalis produced both penta- and heptapeptide phytochelatins (i.e. phytochelatin-2 and phytochelatin-3), and their levels increased in response to sub-lethal levels of cadmium. - Highlights: • Little is known about the role of phytochelatins in metal detoxification in animals. • We detected phytochelatins (PC{sub 2} and PC{sub 3}) in a mollusc species, Lymnaea stagnalis. • Phytochelatins increased in Lymnaea stagnalis when exposed to cadmium. • Future research on phytochelatin responses in molluscs would be valuable.

Effects of sublethal exposure to lead on levels of energetic compounds in Procambarus clarkii (Girard, 1852)

Energy Technology Data Exchange (ETDEWEB)

Martinez, M.; Torreblanca, A.; Del Ramo, J.; Diaz-Mayans, J. (Univ. of Valencia (Spain))

1994-05-01

Lead is neither essential nor beneficial to living organisms; all existing data show that its metabolic effects are adverse. Lead is toxic to all phyla of aquatic biota. Most of the lead discharged into surface water is rapidly incorporated into suspended and bottom sediments. The American red crayfish, Procambarus clarkii, lives in a wide range of environmental conditions that include highly polluted waters. Lead present in take sediments can be available to aquatic animals such as P. clarkii because it is a detritivor and burrow into the sediment. In fact, we found remarkable levels of lead in tissues of P. clarkii caught in Albufera Lake and kept 15 days in clean water (e. g. 223 [mu]g/g dry weight in gills). Furthermore, P. clarkii has a high capacity for lead accumulation from water, and gills were the most important tissue of lead accumulation. Among effects that contaminants have on the physiology of the organisms, energetic state variables are important, since they will alter both survival and reproduction. Hepatopancreas is a major site for the energetic reserve in crayfish and is a site of lead accumulation, although metal concentration in this organ is not as high as gills. The purpose of this study was to examine changes in energy reserves in hepatopancreas and gills of the crayfish P. clarkii, in response to sublethal exposure to lead. Gills are directly exposed to contaminants in the environment, and they are the first organ showing alterations by the action of the contaminants. Hepatopancreas was also chosen due to both, its relevance in the energetic metabolism and its role in heavy metal detoxification mechanisms.

Assessment of Human Exposure to ENMs.

Science.gov (United States)

Jiménez, Araceli Sánchez; van Tongeren, Martie

2017-01-01

Human exposure assessment of engineered nanomaterials (ENMs) is hampered, among other factors, by the difficulty to differentiate ENM from other nanomaterials (incidental to processes or naturally occurring) and the lack of a single metric that can be used for health risk assessment. It is important that the exposure assessment is carried out throughout the entire life-cycle as releases can occur at the different stages of the product life-cycle, from the synthesis, manufacture of the nano-enable product (occupational exposure) to the professional and consumer use of nano-enabled product (consumer exposure) and at the end of life.Occupational exposure surveys should follow a tiered approach, increasing in complexity in terms of instruments used and sampling strategy applied with higher tiers in order tailor the exposure assessment to the specific materials used and workplace exposure scenarios and to reduce uncertainty in assessment of exposure. Assessment of consumer exposure and of releases from end-of-life processes currently relies on release testing of nano-enabled products in laboratory settings.

Effects of sub-lethal neurite outgrowth inhibitory concentrations of chlorpyrifos oxon on cytoskeletal proteins and acetylcholinesterase in differentiating N2a cells

Energy Technology Data Exchange (ETDEWEB)

Flaskos, J., E-mail: flaskos@vet.auth.gr [Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Nikolaidis, E. [Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Harris, W. [School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS (United Kingdom); Sachana, M. [Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Hargreaves, A.J., E-mail: alan.hargreaves@ntu.ac.uk [School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS (United Kingdom)

2011-11-15

Previous work in our laboratory has shown that sub-lethal concentrations (1-10 {mu}M) of chlorpyrifos (CPF), diazinon (DZ) and diazinon oxon (DZO) inhibit the outgrowth of axon-like neurites in differentiating mouse N2a neuroblastoma cells concomitant with altered levels and/or phosphorylation state of axonal cytoskeleton and growth-associated proteins. The aim of the present work was to determine whether chlorpyrifos oxon (CPO) was capable of inhibiting N2a cell differentiation in a similar manner. Using experimental conditions similar to our previous work, sub-lethal concentrations (1-10 {mu}M) of CPO were found to inhibit N2a cell differentiation. However, unlike previous studies with DZ and DZO, there was a high level of sustained inhibition of acetylcholinesterase (AChE) in CPO treated cells. Impairment of neurite outgrowth was also associated with reduced levels of growth associated protein-43 and neurofilament heavy chain (NFH), and the distribution of NFH in cells stained by indirect immunofluorescence was disrupted. However, in contrast to previous findings for DZO, the absolute level of phosphorylated NFH was unaffected by CPO exposure. Taken together, the findings suggest that sub-lethal concentrations of CPO inhibit axon outgrowth in differentiating N2a cells and that this effect involves reduced levels of two proteins that play key roles in axon outgrowth and maintenance. Although the inhibition of neurite outgrowth is unlikely to involve AChE inhibition directly, further work will help to determine whether the persistent inhibition of AChE by CPO can account for the different effects induced by CPO and DZO on the levels of total and phosphorylated NFH. -- Highlights: Black-Right-Pointing-Pointer Sub-lethal levels of chlorpyrifos oxon inhibit neurite outgrowth in N2a cells Black-Right-Pointing-Pointer Acetylcholinesterase exhibits sustained inhibition throughout exposure Black-Right-Pointing-Pointer The levels of neurofilament heavy chain and GAP-43

Effects of sub-lethal neurite outgrowth inhibitory concentrations of chlorpyrifos oxon on cytoskeletal proteins and acetylcholinesterase in differentiating N2a cells

International Nuclear Information System (INIS)

Flaskos, J.; Nikolaidis, E.; Harris, W.; Sachana, M.; Hargreaves, A.J.

2011-01-01

Previous work in our laboratory has shown that sub-lethal concentrations (1–10 μM) of chlorpyrifos (CPF), diazinon (DZ) and diazinon oxon (DZO) inhibit the outgrowth of axon-like neurites in differentiating mouse N2a neuroblastoma cells concomitant with altered levels and/or phosphorylation state of axonal cytoskeleton and growth-associated proteins. The aim of the present work was to determine whether chlorpyrifos oxon (CPO) was capable of inhibiting N2a cell differentiation in a similar manner. Using experimental conditions similar to our previous work, sub-lethal concentrations (1–10 μM) of CPO were found to inhibit N2a cell differentiation. However, unlike previous studies with DZ and DZO, there was a high level of sustained inhibition of acetylcholinesterase (AChE) in CPO treated cells. Impairment of neurite outgrowth was also associated with reduced levels of growth associated protein-43 and neurofilament heavy chain (NFH), and the distribution of NFH in cells stained by indirect immunofluorescence was disrupted. However, in contrast to previous findings for DZO, the absolute level of phosphorylated NFH was unaffected by CPO exposure. Taken together, the findings suggest that sub-lethal concentrations of CPO inhibit axon outgrowth in differentiating N2a cells and that this effect involves reduced levels of two proteins that play key roles in axon outgrowth and maintenance. Although the inhibition of neurite outgrowth is unlikely to involve AChE inhibition directly, further work will help to determine whether the persistent inhibition of AChE by CPO can account for the different effects induced by CPO and DZO on the levels of total and phosphorylated NFH. -- Highlights: ► Sub-lethal levels of chlorpyrifos oxon inhibit neurite outgrowth in N2a cells ► Acetylcholinesterase exhibits sustained inhibition throughout exposure ► The levels of neurofilament heavy chain and GAP-43 protein are reduced ► Neurofilament heavy chain forms aggregates in cell

Use of various acute, sublethal and early life-stage tests to evaluate the toxicity of refinery effluents

International Nuclear Information System (INIS)

Sherry, J.; Scott, B.; Dutka, B.

1997-01-01

The toxicities of effluents from three Ontario, Canada, refineries were assessed with microbes, plants, invertebrates, and fish. Acute toxicity was assessed by the Microtox test, an assay based on electron transport activity in submitochondrial particles, and Daphnia magna (water flea); growth of Selenastrum capricornutum (alga); growth of Lemna minor (aquatic plant); germination of Lactuca sativa (nonaquatic plant); survival, growth, and maturation of Panagrellus redivivus (nematode); and genotoxicity in the SOS-Chromotest. Only the Microtox test and the submitochondrial particle test detected acute toxicity in the effluent samples. Reduced survival and sublethal responses were caused by some effluents, but not all effluents were toxic, and none caused a response in all of the tests applied. The results suggest that the effluent treatment systems used at Ontario refineries have largely eliminated acute toxicity to the organisms in their test battery. Although reduced survival and sublethal effects were detected in some of the effluents, the effects were minor. Some of the tests provided evidence, albeit weak, of variations in the responses of the test organisms to a temporal series of effluent samples. Not unexpectedly, there were also minor differences in the responses of the tests to effluents from the three refineries. The fathead minnow test seems to be a sensitive indicator of the sublethal toxicity of Ontario refinery effluents

Sub-lethal effects of Vip3A toxin on survival, development and fecundity of Heliothis virescens and Plutella xylostella.

Science.gov (United States)

Gulzar, Asim; Wright, Denis J

2015-11-01

The assessment of sub-lethal effects is important to interpret the overall insecticide efficacy in controlling insect pest populations. In addition to the lethal effect, sub-lethal effects may also occur in exposed insects. Vegetative insecticidal proteins (Vips) have shown a broad spectrum of insecticidal activity against many insect pest species. In this study the sub-lethal effects of the Bacillus thuringiensis vegetative insecticidal toxin Vip3A on the development and reproduction of Heliothis virescens F. and Plutella xylostella L. were evaluated in the laboratory. The results indicated that the sub-lethal concentration of Vip3A increased the duration of the larval and pupal stages as compared with the control treatment for both species. The percent pupation and percent adult emergence were significantly lower for Vip3A-treated insects. The proportion of pairs that produced eggs and the longevity of adults were not significantly different between treatments. H. virescens and P. xylostella treated with Vip3A showed an 11 and 17 % decrease in their intrinsic rate of increase (rm) respectively compared with untreated insects. The results from this study will be helpful to develop the strategy to incorporate Vip 3A containing crops in an integrated pest management programme.

Sublethal irradiation promotes invasiveness of neuroblastoma cells

International Nuclear Information System (INIS)

Schweigerer, Lothar; Rave-Fraenk, Margret; Schmidberger, Heinz; Hecht, Monica

2005-01-01

Neuroblastoma is the most frequent extracranial solid tumour of childhood. Despite multiple clinical efforts, clinical outcome has remained poor. Neuroblastoma is considered to be radiosensitive, but some clinical studies including the German trial NB90 failed to show a clinical benefit of radiation therapy. The mechanisms underlying this apparent discrepancy are still unclear. We have therefore investigated the effects of radiation on neuroblastoma cell behaviour in vitro. We show that sublethal doses of irradiation up-regulated the expression of the hepatocyte growth factor (HGF) and its receptor c-Met in some neuroblastoma cell lines. The increase in HGF/c-Met expression was correlated with enhanced invasiveness and activation of proteases degrading the extracellular matrix. Thus, irradiation at sublethal doses may promote the metastatic dissemination of neuroblastoma cells through activating the HGF/c-Met pathway and triggering matrix degradation

The effect of thymus cells on bone marrow transplants into sublethally irradiated mice

International Nuclear Information System (INIS)

Kruszewski, J.A.; Szcylik, C.; Wiktor-Jedrzejczak, W.

1984-01-01

Bone marrow cells formed similar numbers of 10-days spleen colonies in sublethally (6 Gy) irradiated C57B1/6 mice as in lethally (7.5 Gy) irradiated mice i.e. approximately 20 per 10 5 cells. Numbers of 10 day endogenous spleen colonies in sublethally irradiated mice (0.2 to 0.6 per spleen) did not differ significantly from the numbers in lethally irradiated mice. Yet, transplants of 10 7 coisogenic marrow cells into sublethally irradiated mice resulted in predominantly endogenous recovery of granulocyte system as evidenced by utilization of ''beige'' marker for transplanted cells. Nevertheless, transplanted cells engrafted into sublethally irradiated mice were present in their hemopoietic tissues throughout the observation period of 2 months never exceeding 5 to 10% of cells. Thymus cells stimulated endogenous and exogenous spleen colony formation as well as endogenous granulopoietic recovery. Additionally, they increased both the frequency and absolute numbers of graft-derived granulocytic cells in hemopoietic organs of transplanted mice. They failed, however, to essentially change the quantitative relationships between endogenous and exogenous hemopoietic recovery. These results may suggest that spleen colony studies are not suitable for prediction of events following bone marrow transplant into sublethally irradiated mice. Simultaneously, they have strengthened the necessity for appropriate conditioning of recipients of marrow transplants. (orig.) [de

Challenges and perspectives of nanoparticle exposure assessment.

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Lee, Ji Hyun; Moon, Min Chaul; Lee, Joon Yeob; Yu, Il Je

2010-06-01

Nanoparticle exposure assessment presents a unique challenge in the field of occupational and environmental health. With the commercialization of nanotechnology, exposure usually starts from the workplace and then spreads to environment and consumer exposure. This report discusses the current trends of nanoparticle exposure assessment, including the definition of nanotechnology relevant terms, essential physicochemical properties for nanomaterial characterization, current international activities related nanomaterial safety, and exposure assessment standard development for nanotechnology. Further this report describes challenges of nanoparticle exposure assessment such as background measurement, metrics of nanoparticle exposure assessment and personal sampling.

[Sublethal effects of spinetoram and azadirachtin on development and reproduction of Frankliniella occidentalis (Pergande).

Science.gov (United States)

Yang, Guang Ming; Zhi, Jun Rui; Li, Shun Xin; Liu, Li

2016-11-18

To evaluate the sublethal effects of spinetoram and azadirachtin on western flower thrips, Frankliniella occidentalis, leaf dipping method was used to determine their sublethal concentrations (LC 25 ) on the 2 nd instar nymph, and their influences on development and reproduction of F. occidentalis were studied. The results showed exposure of sublethal concentrations of spinetoram and azadirachtin to F. accidentalis had different degrees of effects on this insect pest. Under bisexual reproduction, the LC 25 spinetoram had no significant influences on pre-oviposition period, female adult longevity and fecundity, but male adult longevity was significantly shorter than the control. The LC 25 azadirachtin significantly reduced fecundity and prolonged pre-oviposition period. Under parthenogenesis, the LC 25 spinetoram and azadirachtin extended the pre-oviposition duration, whereas the LC 25 azadirachtin shortened the female adult longevity and significantly decreased fecundity. The LC 25 spinetoram and azadirachtin had different influences on developmental duration of each stage of next generation. The immature stage in treatment group of the LC 25 spinetoram was shorter than that in treatment group of the LC 25 azadirachtin, under bisexual reproduction or parthenogenesis. Intrinsic rate of increase (r m ) and finite rate of increase (λ) of population treated by the LC 25 spinetoram were higher than those of the control, whereas the r m , R 0 , and λ of population treated by the LC 25 azadirachtin were lower than those of the control. The findings indicated that the effects of the LC 25 spinetoram and azadirachtin on the development and reproduction of F. accidentalis were different. The LC 25 spinetoram had certain stimulating effect, whereas the LC 25 azadirach-tinon had significant inhibitory effect. Two biopesticides' influences were related with the reproductive patterns of F. accidentalis.

Crop-emptying rate and the design of pesticide risk assessment schemes in the honey bee and wild bees (Hymenoptera: Apidae).

Science.gov (United States)

Fournier, Alice; Rollin, Orianne; Le Féon, Violette; Decourtye, Axel; Henry, Mickaël

2014-02-01

Recent scientific literature and reports from official sanitary agencies have pointed out the deficiency of current pesticide risk assessment processes regarding sublethal effects on pollinators. Sublethal effects include troubles in learning performance, orientation skills, or mobility, with possible contribution to substantial dysfunction at population scale. However, the study of sublethal effects is currently limited by considerable knowledge gaps, particularly for the numerous pollinators other than the honey bee Apis mellifera L.--the traditional model for pesticide risk assessment in pollinators. Here, we propose to use the crop-emptying time as a rule of thumb to guide the design of oral exposure experiments in the honey bee and wild bees. The administration of contaminated sucrose solutions is typically followed by a fasting time lapse to allow complete assimilation before the behavioral tests. The fasting duration should at least encompass the crop-emptying time, because no absorption takes place in the crop. We assessed crop-emptying rate in fasted bees and how it relates 1) with sucrose solution concentration in the honey bee and 2) with body mass in wild bees. Fasting duration required for complete crop emptying in honey bees fed 20 microl of a 50% sucrose solution was nearly 2 h. Actual fasting durations are usually shorter in toxicological studies, suggesting incomplete crop emptying, and therefore partial assimilation of experimental solutions that could imply underestimation of sublethal effects. We also found faster crop-emptying rates in large wild bees compared with smaller wild bees, and suggest operative rules to adapt sublethal assessment schemes accordingly.

Sub-lethal toxicity of chlorpyrifos on Common carp, Cyprinus carpio (Linnaeus, 1758: Biochemical response

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Mahdi Banaee

2014-01-01

Full Text Available Chlorpyrifos, an organophosphate pesticide, is widely used to control pests in agriculture farms and orchards of fruit trees. In this study, the fish were exposed to sub-lethal concentrations of chlorpyrifos which were determined based on numerical value of 96 h LC50. Blood was sampled after 10, 20 and 30 days and biochemical parameters including glucose, total protein, albumin, globulin, triglyceride and cholesterol levels, and aspartate aminotransferase (AST, alanine aminotransferase (ALT, lactate dehydrogenase (LDH, creatine kinase (CK, alkaline phosphatase (ALP and acetylcholinsetrase (AChE activities were measured. Behavioral changes in the fish were also recorded during the experiment. Unbalanced swimming, swimming in the surface water and hyperglycemia, increased blood triglyceride, and increased levels of AST, LDH and CK activities as well as decreased levels of AChE activity were important changes that were observed in the specimens exposed to chlorpyrifos during experimental periods. The most important alterations in the blood biochemical parameters were measured in the specimens exposed to 40 µg/L chlorpyrifos on the 20th and 30th day of the trial. In conclusion, results of the present study indicated that exposure to sub-lethal concentrations of chlorpyrifos as low as 40 µg/L may cause biochemical and behavioral changes in Cyprinus carpio.

Sublethal exposure to commercial formulations of the herbicides dicamba, 2,4-dichlorophenoxyacetic acid, and glyphosate cause changes in antibiotic susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium.

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Kurenbach, Brigitta; Marjoshi, Delphine; Amábile-Cuevas, Carlos F; Ferguson, Gayle C; Godsoe, William; Gibson, Paddy; Heinemann, Jack A

2015-03-24

Biocides, such as herbicides, are routinely tested for toxicity but not for sublethal effects on microbes. Many biocides are known to induce an adaptive multiple-antibiotic resistance phenotype. This can be due to either an increase in the expression of efflux pumps, a reduced synthesis of outer membrane porins, or both. Exposures of Escherichia coli and Salmonella enterica serovar Typhimurium to commercial formulations of three herbicides-dicamba (Kamba), 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate (Roundup)-were found to induce a changed response to antibiotics. Killing curves in the presence and absence of sublethal herbicide concentrations showed that the directions and the magnitudes of responses varied by herbicide, antibiotic, and species. When induced, MICs of antibiotics of five different classes changed up to 6-fold. In some cases the MIC increased, and in others it decreased. Herbicide concentrations needed to invoke the maximal response were above current food maximum residue levels but within application levels for all herbicides. Compounds that could cause induction had additive effects in combination. The role of soxS, an inducer of the AcrAB efflux pump, was tested in β-galactosidase assays with soxS-lacZ fusion strains of E. coli. Dicamba was a moderate inducer of the sox regulon. Growth assays with Phe-Arg β-naphtylamide (PAβN), an efflux pump inhibitor, confirmed a significant role of efflux in the increased tolerance of E. coli to chloramphenicol in the presence of dicamba and to kanamycin in the presence of glyphosate. Pathways of exposure with relevance to the health of humans, domestic animals, and critical insects are discussed. Increasingly common chemicals used in agriculture, domestic gardens, and public places can induce a multiple-antibiotic resistance phenotype in potential pathogens. The effect occurs upon simultaneous exposure to antibiotics and is faster than the lethal effect of antibiotics. The magnitude of the

Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

Science.gov (United States)

Pan, Ying; Yan, Shi-Wei; Li, Ruo-Zhu; Hu, Yi-Wen; Chang, Xue-Xiu

2017-01-01

Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L-1), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L-1) to determine the effects of this antibiotic in plankton systems. In 96-h-long lethal experiment, mortality rates of D. magna increased significantly with increasing NOR concentration and exposure time. In sublethal experiments, heartbeat rate decreased, while time ratio of vertical to horizontal swimming (TVH) and the duration of quiescence increased in D. magna individuals exposed to increasing NOR concentrations after 4 and 12 h of exposure. These collectively led to decreases in both average swimming ability and feeding rate, consistent with the positive relationship between average swimming ability and feeding rate. Overall, results indicate that, by affecting zooplankton heartbeat rate and behavior, NOR decreased feeding efficiency of D. magna even at low doses, therefore, it might seriously compromise ecosystem health and function.

The assessment of sublethal effects of pollutants in the sea. Review of the problems.

Science.gov (United States)

Waldichuk, M

1979-08-08

Sublethal effects of pollution may be significant to survival of a stock of marine fish or even a species. Such effects sometimes lead to reproductive failure and have been identified so far only in freshwater systems. Atlantic salmon have disappeared from many streams in Europe and eastern North America, partly as a result of pollution in their freshwater spawning areas and in their estuarine nursing grounds. Reductions in populations of marine fishes due to pollution solely have not yet been demonstrated. However, Baltic Sea seals, where reproductive failure is apparently associated with high concentrations of DDT and polychlorinated biphenyl in the blubber, may have suffered a decline owing to the presence of these organochlorines. Sublethal effects of pollutants have been studied in the laboratory, essentially under four categories: (1) physiology (growth, swimming performance, respiration, circulation); (2) biochemistry/cell structure (blood chemistry, enzyme activity, endocrinology, histochemistry); (3) behaviour/neurophysiology; and (4) reproduction. Not all pollutants elicit meaningful responses in all categories, and a response is not always linear with pollutant concentration. For application to survival of populations the response has to be ultimately related to a healthy progression through a full life cycle, including successful reproduction. In recent time, physiological studies have moved into polluted marine environments with mobile laboratories having continuous sampling capability, to observe effects of pollutants in situ on marine organisms. The Controlled Ecosystem Pollution Experiment (Cepex) in Saanich Inlet, British Columbia, endeavours to investigate the effects of low concentrations of pollutants on marine organisms in large plastic silos having a slow replacement of water.

Human Exposure Assessment for Air Pollution.

Science.gov (United States)

Han, Bin; Hu, Li-Wen; Bai, Zhipeng

2017-01-01

Assessment of human exposure to air pollution is a fundamental part of the more general process of health risk assessment. The measurement methods for exposure assessment now include personal exposure monitoring, indoor-outdoor sampling, mobile monitoring, and exposure assessment modeling (such as proximity models, interpolation model, air dispersion models, and land-use regression (LUR) models). Among these methods, personal exposure measurement is considered to be the most accurate method of pollutant exposure assessment until now, since it can better quantify observed differences and better reflect exposure among smaller groups of people at ground level. And since the great differences of geographical environment, source distribution, pollution characteristics, economic conditions, and living habits, there is a wide range of differences between indoor, outdoor, and individual air pollution exposure in different regions of China. In general, the indoor particles in most Chinese families comprise infiltrated outdoor particles, particles generated indoors, and a few secondary organic aerosol particles, and in most cases, outdoor particle pollution concentrations are a major contributor to indoor concentrations in China. Furthermore, since the time, energy, and expense are limited, it is difficult to measure the concentration of pollutants for each individual. In recent years, obtaining the concentration of air pollutants by using a variety of exposure assessment models is becoming a main method which could solve the problem of the increasing number of individuals in epidemiology studies.

Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus.

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Christine R Lattin

Full Text Available Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT. Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus. We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group. We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9 or control diets (n = 8, we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus).

Science.gov (United States)

Lattin, Christine R; Ngai, Heather M; Romero, L Michael

2014-01-01

Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA) axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT). Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus). We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group). We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9) or control diets (n = 8), we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

Effect of set up time on sublethal repair in multifield fractionated radiotherapy

International Nuclear Information System (INIS)

Kehwar, T.S.; Beriwal, Sushil; Sharma, S.C.

1998-01-01

The sublethal repair between two doses given with a variable time interval for mammalian cells in tissue culture was first demonstrated successfully by Elkind and Sutton. Subsequently on the basis of concept of sublethal damage repair between fractions, the radio therapists and radio biologists realized that dose can be increased by increasing the small size fractions. This concept is successfully being used in modern radiotherapy

Toxicokinetic-toxicodynamic modeling of quantal and graded sublethal endpoints: a brief discussion of concepts

NARCIS (Netherlands)

Ashauer, R.; Agatz, A.; Albert, C.; Ducrot, V.; Galic, N.G.; Hendriks, J.; Jager, T.; Kretschmann, A.; O'Connor, I.; Rubach, M.N.; Nyman, M.; Schmitt, W.; Stadnicka, J.; Brink, van den P.J.

2011-01-01

We report on the advantages and problems of using toxicokinetic-toxicodynamic (TKTD) models for the analysis, understanding, and simulation of sublethal effects. Only a few toxicodynamic approaches for sublethal effects are available. These differ in their effect mechanism and emphasis on linkages

Effects of thermal stress and nickel exposure on biomarkers responses in Mytilus galloprovincialis (Lam).

Science.gov (United States)

Attig, Hajer; Kamel, Naouel; Sforzini, Susanna; Dagnino, Alessandro; Jamel, Jebali; Boussetta, Hamadi; Viarengo, Aldo; Banni, Mohamed

2014-03-01

The present work aimed to assess the Mytilus galloprovincialis digestive gland biomarkers responses to nickel (Ni) exposure along with a heat stress gradient. Mussels were exposed to a sublethal dose of nickel (13 μM) along with a temperature gradient (18 °C, 20 °C, 22 °C, 24 °C and 26 °C) for 4 days. Metallothionein (MTs) content was assessed as specific response to metals. Catalase (CAT), glutathione S-transferase (GST) activities and malondialdehyde (MDA) were measured as biomarkers of oxidative stress and lipid peroxidation. The cholinergic system was monitored using the acetylcholinesterase activity (AChE). Moreover, Ni uptakes along with the exposure temperatures were assessed. A correlation matrix (CM) between the investigated biomarkers and the exposure temperatures and a Principal Component Analysis (PCA) were achieved. Our data showed a negative effect of temperature increase on mussel's antioxidant and detoxification response to Ni exposure being more pronounced in animals exposed to the 24 °C and 26 °C. Copyright © 2013 Elsevier Ltd. All rights reserved.

Concentration of electrolyte reserves of the juvenile african catfish clarias gariepinus (burchell, 1822) exposed to sublethal concentrations of portland cement powder in solution

International Nuclear Information System (INIS)

Adamu, M.K.; Francis, O.A.

2008-01-01

The study investigated the effect of sublethal concentrations (39.10, 19.55, 9.87 and 0.00 mg/l) of Portland cement powder in solution on the electrolyte reserves (sodium, potassium, calcium, chloride and inorganic phosphorus) in the serum, liver and kidney of the juvenile African catfish Clarias gariepinus after a 15 day exposure period. The basic function of the determined electrolyte reserves in the body lies in controlling fluid distribution, intra and extra cellular acidobasic equilibrium, maintaining osmotic pressure of body fluid and normal neuro-muscular irritability. The result revealed significant (P 0.05) changes in inorganic phosphorus. Sodium, calcium, chloride and inorganic phosphorus and potassium were significantly (P 0.05) different in liver and kidney, respectively. Ipso-facto, the effector organs viz: liver and kidney of teleost species - Clarias gariepinus which are primarily responsible for regulating water and ionic movement between external and internal milieu of fishes are susceptible to deleterious effects of Portland cement powder thus sublethal concentration (39.10 mg/l) of Portland cement powder in solution after a 15 day exposure has been most toxic and debilitating to the test fish. (author)

Suggested Methods for Assessment of Accidental External Exposure and Internal Contamination of Workers and their Medical Management

International Nuclear Information System (INIS)

Mahmoud, K.A.; Morsy, Samira M.; Hanna, I.R.A.; Hafez, M.B.; Mohamed, H.O.; Jahns, E.; Saied, F.I.A.

1969-01-01

Certain assumptions are given for the amount of fission products released from a research reactor after the occurrence of an accident. The size and location of radioactive cloud are assumed, and the corresponding external and internal exposures of workers are computed. A method is suggested for assessment of accidental external radiation dose based on experimental studies performed on the changes of quenching effect of plasma or sera as a.result of whole- body gamma-radiation ranging from 25-200 rems. For assessment of accidentally internally incorporated gamma emitters we suggest the standard chair whole-body counter technique which was found to detect reliably 1/100 of the maximum permissible body burden within eight minutes. It was also suggested that a separation method based on the use of absorption phenomena observed for Sephadex (gel resin) can be applied for quick determination of gross alpha activity in urine. For management of accidentally exposed workers to radiation doses of a lethal or sublethal nature, bone-marrow transplantation therapy and blood component therapy in sterile rooms is discussed in the light of experience gained from treatment of leukaemia with intensive chemotherapy. (author)

Immunocytoadherence and sublethal irradiation

International Nuclear Information System (INIS)

Beaumariage, M.L.; Hiesche, K.; Revesz, L.; Haot, J.

1975-01-01

In sublethally irradiated CBA mice, the relative and absolute numbers of spontaneous rosette forming cells against sheep erythrocytes are markedly decreased in bone marrow. The decrease of the absolute number of spontaneous RFC is also important in the spleen in spite of an increase of the RFC relative number above the normal values between the 8th and 12th day after irradiation. The graft of normal bone marrow cells immediately after irradiation or the shielding of a medullary area during irradiation promotes the recovery of the immunocytoadherence capacity of the bone marrow cells but not of the spleen cells [fr

Potential for sublethal insecticide exposure to impact vector competence of Aedes albopictus (Diptera: Culicidae for dengue and Zika viruses

Directory of Open Access Journals (Sweden)

Richards SL

2017-05-01

Full Text Available Stephanie L Richards, Avian V White, Jo Anne G Balanay Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Greenville, NC, USA Abstract: Chikungunya, dengue, and Zika viruses (CHIKV, family Togaviridae, genus Alphavirus; DENV and ZIKV, family Flaviviridae, genus Flavivirus are arboviruses that cause human epidemics. Due to the lack of vaccines for many mosquito-borne diseases, there is a need for mosquito control. In the US and other regions, residual barrier insecticide sprays are applied to foliage where female mosquitoes rest and/or sugar feed between blood meals. Residual sprays are an important control method for anthropogenic day-active sylvan mosquitoes such as Aedes albopictus (vector of CHIKV, DENV, and ZIKV that are difficult to control using ultralow-volume sprays applied only at dusk or dawn when these mosquitoes are not active. In this exploratory study, we analyzed the extent to which ingestion of a sublethal dose of the active ingredient bifenthrin affected vector competence (i.e., infection, dissemination, and transmission of Ae. albopictus for DENV and ZIKV. Two incubation periods (IPs; 7 and 14 d were tested at 28°C for insecticide-fed and sugar-fed mosquitoes. We show that mosquitoes that were fed bifenthrin (0.128 µg/mL mixed with sucrose solution exhibited significantly lower DENV infection rates and body titers after a 14-d IP. During the 7-d IP, one mosquito (sugar group transmitted ZIKV. During the 14-d IP, 100% of mosquitoes showed body and leg ZIKV infections, and one mosquito (sugar+bifenthrin group transmitted ZIKV. This is a preliminary communication, and more studies will be required to further investigate these findings. We expect the findings of this small-scale study to spur larger-scale investigations of the impacts of insecticides on mechanisms regulating vector competence, and exposure to other active ingredients, and aid in development of new

Biomonitoring of ciguatoxin exposure in mice using blood collection cards.

Science.gov (United States)

Bottein Dechraoui, M-Yasmine; Wang, Zhihong; Turquet, Jean; Chinain, Mireille; Darius, Taiana; Cruchet, Philippe; Radwan, Faisal F Y; Dickey, Robert W; Ramsdell, John S

2005-09-01

Ciguatera is a human food poisoning caused by consumption of tropical and subtropical fish that have, through their diet, accumulated ciguatoxins in their tissues. This study used laboratory mice to investigate the potential to apply blood collection cards to biomonitor ciguatoxin exposure. Quantitation by the neuroblastoma cytotoxicity assay of Caribbean ciguatoxin (C-CTX-1) spiked into mice blood was made with good precision and recovery. The blood collected from mice exposed to a sublethal dose of Caribbean ciguatoxic extract (0.59 ng/g C-CTX-1 equivalents) was analyzed and found to contain detectable toxin levels at least 12 h post-exposure. Calculated concentration varied from 0.25 ng/ml at 30 min post-exposure to 0.12 ng/ml at 12 h. A dose response mice exposure revealed a linear dose-dependent increase of ciguatoxin activity in mice blood, with more polar ciguatoxin congeners contributing to 89% of the total toxicity. Finally, the toxin measurement in mice blood exposed to toxic extracts from the Indian Ocean or from the Pacific Ocean showed that the blood collection card method could be extended to each of the three known ciguatoxin families (C-CTX, I-CTX and P-CTX). The low matrix effect of extracted dried-blood samples (used at 1:10 or 1:20 dilution) and the high sensitivity of the neuroblastoma assay (limit of detection 0.006 ng/ml C-CTX-1), determined that the blood collection card method is suitable to monitor ciguatoxin at sublethal doses in mice and opens the potential to be a useful procedure for fish screening, environmental risk assessment or clinical diagnosis of ciguatera fish poisoning in humans or marine mammals.

An Exposure Assessment of Polybrominated Diphenyl Ethers ...

Science.gov (United States)

EPA announced the availability of the final report, An Exposure Assessment of Polybrominated Diphenyl Ethers. This report provides a comprehensive assessment of the exposure of Americans to this class of persistent organic pollutants. Individual chapters in this document address: the production, use, and lifecycle of PBDEs; environmental fate; environmental levels; and human exposure. This final report addresses the exposure assessment needs identified in the OPBDE Workgroup project plan. It provides a comprehensive assessment of the exposure of Americans to this class of persistent organic pollutants. Individual chapters in this document address: the production, use, and lifecycle of PBDEs; environmental fate; environmental levels; and human exposure.

Induction of high tolerance to artemisinin by sub-lethal administration: A new in vitro model of P. falciparum.

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Serena De Lucia

Full Text Available Artemisinin resistance is a major threat to malaria control efforts. Resistance is characterized by an increase in the Plasmodium falciparum parasite clearance half-life following treatment with artemisinin-based combination therapies (ACTs and an increase in the percentage of surviving parasites. The remarkably short blood half-life of artemisinin derivatives may contribute to drug-resistance, possibly through factors including sub-lethal plasma concentrations and inadequate exposure. Here we selected for a new strain of artemisinin resistant parasites, termed the artemisinin resistant strain 1 (ARS1, by treating P. falciparum Palo Alto (PA cultures with sub-lethal concentrations of dihydroartemisinin (DHA. The resistance phenotype was maintained for over 1 year through monthly maintenance treatments with low doses of 2.5 nM DHA. There was a moderate increase in the DHA IC50 in ARS1 when compared with parental strain PA after 72 h of drug exposure (from 0.68 nM to 2 nM DHA. In addition, ARS1 survived treatment physiologically relevant DHA concentrations (700 nM observed in patients. Furthermore, we confirmed a lack of cross-resistance against a panel of antimalarials commonly used as partner drugs in ACTs. Finally, ARS1 did not contain Pfk13 propeller domain mutations associated with ART resistance in the Greater Mekong Region. With a stable growth rate, ARS1 represents a valuable tool for the development of new antimalarial compounds and studies to further elucidate the mechanisms of ART resistance.

Influence of UVB radiation on the lethal and sublethal toxicity of dispersed crude oil to planktonic copepod nauplii.

Science.gov (United States)

Almeda, Rodrigo; Harvey, Tracy E; Connelly, Tara L; Baca, Sarah; Buskey, Edward J

2016-06-01

Toxic effects of petroleum to marine zooplankton have been generally investigated using dissolved petroleum hydrocarbons and in the absence of sunlight. In this study, we determined the influence of natural ultraviolet B (UVB) radiation on the lethal and sublethal toxicity of dispersed crude oil to naupliar stages of the planktonic copepods Acartia tonsa, Temora turbinata and Pseudodiaptomus pelagicus. Low concentrations of dispersed crude oil (1 μL L(-1)) caused a significant reduction in survival, growth and swimming activity of copepod nauplii after 48 h of exposure. UVB radiation increased toxicity of dispersed crude oil by 1.3-3.8 times, depending on the experiment and measured variables. Ingestion of crude oil droplets may increase photoenhanced toxicity of crude oil to copepod nauplii by enhancing photosensitization. Photoenhanced sublethal toxicity was significantly higher when T. turbinata nauplii were exposed to dispersant-treated oil than crude oil alone, suggesting that chemical dispersion of crude oil may promote photoenhanced toxicity to marine zooplankton. Our results demonstrate that acute exposure to concentrations of dispersed crude oil and dispersant (Corexit 9500) commonly found in the sea after oil spills are highly toxic to copepod nauplii and that natural levels of UVB radiation substantially increase the toxicity of crude oil to these planktonic organisms. Overall, this study emphasizes the importance of considering sunlight in petroleum toxicological studies and models to better estimate the impact of crude oil spills on marine zooplankton. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Lethal and Sublethal Effects of Fenpropathrin on the Biological Performance of Scolothrips longicornis (Thysanoptera: Thripidae)

DEFF Research Database (Denmark)

Pakyari, Hajar; Enkegaard, Annie

2013-01-01

Determination of negative nontarget effects of pesticides on beneficial organisms by measuring only lethal effects is likely to underestimate effects of sublethal doses. In this study, the sublethal effects of fenpropathrin on the predatory thrips Scolothrips longicornis Priesner (Thysanoptera: T...

Sublethal Heavy Metal Stress Stimulates Innate Immunity in Tomato

Directory of Open Access Journals (Sweden)

Nilanjan Chakraborty

2015-01-01

Full Text Available Effect of sublethal heavy metal stress as plant biotic elicitor for triggering innate immunity in tomato plant was investigated. Copper in in vivo condition induced accumulation of defense enzymes like peroxidase (PO, polyphenol oxidase (PPO, phenylalanine ammonia-lyase (PAL, and β-1,3 glucanase along with higher accumulation of total phenol, antioxidative enzymes (catalase and ascorbate peroxidase, and total chlorophyll content. Furthermore, the treatment also induced nitric oxide (NO production which was confirmed by realtime visualization of NO burst using a fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2DA and spectrophotometric analysis. The result suggested that the sublethal dose of heavy metal can induce an array of plant defense responses that lead to the improvement of innate immunity in plants.

Life cycle responses of the midge Chironomus riparius to polycyclic aromatic compound exposure

NARCIS (Netherlands)

León Paumen, M.; Borgman, E.; Kraak, M.H.S.; van Gestel, C.A.M.; Admiraal, W.

2008-01-01

During acute exposure, polycyclic aromatic compounds (PACs) act mainly by narcosis, but during chronic exposure the same compounds may exert sublethal life cycle effects. The aim of this study was therefore to evaluate the chronic effects of sediment spiked PACs on the emergence of the midge

Toxicokinetic-toxicodynamic modelling of quantal and graded sub-lethal endpoints - a brief discussion of concepts.

NARCIS (Netherlands)

Ashauer, R.; Agatz, A.; Albert, C.; Ducrot, V.; Galic, N.; Hendriks, A.J.; Jager, T.; Kretschmann, A.; O'Connor, I.; Rubach, M.N.; Nyman, A.M.; Schmitt, W.; Stadnicka, J.; van den Brink, P.; Preuss, T.G.

2011-01-01

We report on the advantages and problems of using toxicokinetic-toxicodynamic (TKTD) models for the analysis, understanding, and simulation of sublethal effects. Only a few toxicodynamic approaches for sublethal effects are available. These differ in their effect mechanism and emphasis on linkages

Relationship between Sublethal Injury and Inactivation of Yeast Cells by the Combination of Sorbic Acid and Pulsed Electric Fields▿

OpenAIRE

Somolinos, M.; García, D.; Condón, S.; Mañas, P.; Pagán, R.

2007-01-01

The objective of this study was to investigate the occurrence of sublethal injury after the pulsed-electric-field (PEF) treatment of two yeasts, Dekkera bruxellensis and Saccharomyces cerevisiae, as well as the relation of sublethal injury to the inactivating effect of the combination of PEF and sorbic acid. PEF caused sublethal injury in both yeasts: more than 90% of surviving D. bruxellensis cells and 99% of surviving S. cerevisiae cells were sublethally injured after 50 pulses at 12 kV/cm ...

Sublethal toxicity and biotransformation of pyrene in Lumbriculus variegatus (Oligochaeta)

International Nuclear Information System (INIS)

Maeenpaeae, K.; Leppaenen, M.T.; Kukkonen, J.V.K.

2009-01-01

The aim of this work was to study the toxicity and biotransformation of polyaromatic hydrocarbon (PAH) pyrene in the oligochaete aquatic worm, Lumbriculus variegatus. PAHs are ubiquitous environmental pollutants that pose a hazard to aquatic organisms, and metabolizing capability is poorly known in the case of many invertebrate species. To study the toxicity and biotransformation of pyrene, the worm was exposed for 15 days to various concentrations of water-borne pyrene. The dorsal blood vessel pulse rate was used as a sublethal endpoint. Pyrene biotransformation by L. variegatus was studied and the critical body residues (CBR) were estimated for pyrene toxicity. The toxicokinetics of pyrene uptake was evaluated. A combination of radiolabeled ( 14 C) and nonlabeled pyrene was used in the exposures, and liquid scintillation counting (LSC) and high-pressure liquid chromatography were employed in both water and tissue residue analyses. The results showed that L. variegatus was moderately able to metabolize pyrene to 1-hydroxypyrene (1-HP), thus demonstrating that the phase-I-like oxidizing enzyme system metabolizes pyrene in L. variegatus. The amount of the 1-HP was 1-2% of the amount of pyrene in the worm tissues. The exposure to pyrene reduced the blood vessel pulse rate significantly (p < 0.05), showing that pyrene had a narcotic effect. The estimated CBRs remained constant during the exposure time, varying from 0.120 to 0.174 mmol pyrene/kg worm wet weight. The bioconcentration factors (BCF) decreased as exposure concentration increased. It was suggested that the increased toxicity of pyrene accounted for the decrease in BCFs by lowering the activity of the organism

Predicting sublethal effects of herbicides on terrestrial non-crop plant species in the field from greenhouse data

International Nuclear Information System (INIS)

Riemens, Marleen M.; Dueck, Thom; Kempenaar, Corne

2008-01-01

Guidelines provided by OECD and EPPO allow the use of data obtained in greenhouse experiments in the risk assessment for pesticides to non-target terrestrial plants in the field. The present study was undertaken to investigate the predictability of effects on field-grown plants using greenhouse data. In addition, the influence of plant development stage on plant sensitivity and herbicide efficacy, the influence of the surrounding vegetation on individual plant sensitivity and of sublethal herbicide doses on the biomass, recovery and reproduction of non-crop plants was studied. Results show that in the future, it might well be possible to translate results from greenhouse experiments to field situations, given sufficient experimental data. The results also suggest consequences at the population level. Even when only marginal effects on the biomass of non-target plants are expected, their seed production and thereby survival at the population level may be negatively affected. - The response of greenhouse-grown wild plant species to herbicide exposure could be related to the response of the same species when grown in the field

Acute exposure to selenium disrupts associative conditioning and long-term memory recall in honey bees (Apis mellifera).

Science.gov (United States)

Burden, Christina M; Elmore, Christopher; Hladun, Kristen R; Trumble, John T; Smith, Brian H

2016-05-01

A plethora of toxic compounds - including pesticides, heavy metals, and metalloids - have been detected in honey bees (Apis mellifera) and their colonies. One such compound is selenium, which bees are exposed to by consuming nectar and pollen from flowers grown in contaminated areas. Though selenium is lethal at high concentrations, sublethal exposure may also impair honey bees' ability to function normally. Examining the effect of selenium exposure on learning and memory provides a sensitive assay with which to identify sublethal effects on honey bee health and behavior. To determine whether sublethal selenium exposure causes learning and memory deficits, we used proboscis extension reflex conditioning coupled with recall tests 30min and 24h post-conditioning. We exposed forager honey bees to a single sublethal dose of selenium, and 3h later we used an olfactory conditioning assay to train the bees to discriminate between one odor associated with sucrose-reinforcement and a second unreinforced odor. Following conditioning we tested short- and long-term recall of the task. Acute exposure to as little as 1.8ng of an inorganic form of selenium (sodium selenate) before conditioning caused a reduction in behavioral performance during conditioning. And, exposure to 18ng of either an inorganic form (sodium selenate) or an organic form (methylseleno-l-cysteine) of selenium caused a reduction in the bees' performance during the long-term recall test. These concentrations of selenium are lower than those found in the nectar of plants grown in selenium-contaminated soil, indicating that even low-grade selenium toxicity produces significant learning and memory impairments. This may reduce foragers' ability to effectively gather resources for the colony or nurse bees' ability to care for and maintain a healthy colony. Copyright © 2016. Published by Elsevier Inc.

Exploring Global Exposure Factors Resources for Use in Consumer Exposure Assessments

Science.gov (United States)

Zaleski, Rosemary T.; Egeghy, Peter P.; Hakkinen, Pertti J.

2016-01-01

This publication serves as a global comprehensive resource for readers seeking exposure factor data and information relevant to consumer exposure assessment. It describes the types of information that may be found in various official surveys and online and published resources. The relevant exposure factors cover a broad range, including general exposure factor data found in published compendia and databases and resources about specific exposure factors, such as human activity patterns and housing information. Also included are resources on exposure factors related to specific types of consumer products and the associated patterns of use, such as for a type of personal care product or a type of children’s toy. Further, a section on using exposure factors for designing representative exposure scenarios is included, along with a look into the future for databases and other exposure science developments relevant for consumer exposure assessment. PMID:27455300

Asbestos Exposure Assessment Database

Science.gov (United States)

Arcot, Divya K.

2010-01-01

Exposure to particular hazardous materials in a work environment is dangerous to the employees who work directly with or around the materials as well as those who come in contact with them indirectly. In order to maintain a national standard for safe working environments and protect worker health, the Occupational Safety and Health Administration (OSHA) has set forth numerous precautionary regulations. NASA has been proactive in adhering to these regulations by implementing standards which are often stricter than regulation limits and administering frequent health risk assessments. The primary objective of this project is to create the infrastructure for an Asbestos Exposure Assessment Database specific to NASA Johnson Space Center (JSC) which will compile all of the exposure assessment data into a well-organized, navigable format. The data includes Sample Types, Samples Durations, Crafts of those from whom samples were collected, Job Performance Requirements (JPR) numbers, Phased Contrast Microscopy (PCM) and Transmission Electron Microscopy (TEM) results and qualifiers, Personal Protective Equipment (PPE), and names of industrial hygienists who performed the monitoring. This database will allow NASA to provide OSHA with specific information demonstrating that JSC s work procedures are protective enough to minimize the risk of future disease from the exposures. The data has been collected by the NASA contractors Computer Sciences Corporation (CSC) and Wyle Laboratories. The personal exposure samples were collected from devices worn by laborers working at JSC and by building occupants located in asbestos-containing buildings.

Induced tolerance from a sublethal insecticide leads to cross-tolerance to other insecticides.

Science.gov (United States)

Hua, Jessica; Jones, Devin K; Relyea, Rick A

2014-04-01

As global pesticide use increases, the ability to rapidly respond to pesticides by increasing tolerance has important implications for the persistence of nontarget organisms. A recent study of larval amphibians discovered that increased tolerance can be induced by an early exposure to low concentrations of a pesticide. Since natural systems are often exposed to a variety of pesticides that vary in mode of action, we need to know whether the induction of increased tolerance to one pesticide confers increased tolerance to other pesticides. Using larval wood frogs (Lithobates sylvaticus), we investigated whether induction of increased tolerance to the insecticide carbaryl (AChE-inhibitor) can induce increased tolerance to other insecticides that have the same mode of action (chlorpyrifos, malathion) or a different mode of action (Na(+)channel-interfering insecticides; permethrin, cypermethrin). We found that embryonic exposure to sublethal concentrations of carbaryl induced higher tolerance to carbaryl and increased cross-tolerance to malathion and cypermethrin but not to chlorpyrifos or permethrin. In one case, the embryonic exposure to carbaryl induced tolerance in a nonlinear pattern (hormesis). These results demonstrate that that the newly discovered phenomenon of induced tolerance also provides induced cross-tolerance that is not restricted to pesticides with the same mode of action.

Exposure Assessment Tools by Chemical Classes - Nanomaterials

Science.gov (United States)

EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

Sublethal concentrations of ichthyotoxic alga Prymnesium parvum affect rainbow trout susceptibility to viral haemorrhagic septicaemia virus

DEFF Research Database (Denmark)

Andersen, Nikolaj Gedsted; Lorenzen, Ellen; Boutrup, Torsten Snogdal

2016-01-01

Ichthyotoxic algal blooms are normally considered a threat to maricultured fish only when blooms reach lethal cell concentrations. The degree to which sublethal algal concentrations challenge the health of the fish during blooms is practically unknown. In this study, we analysed whether sublethal...

Exposure Assessment Tools by Tiers and Types - Deterministic and Probabilistic Assessments

Science.gov (United States)

EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

Determinants of Dermal Exposure Relevant for Exposure Modelling in Regulatory Risk Assessment

NARCIS (Netherlands)

Marquart, J.; Brouwer, D.H.; Gijsbers, J.H.J.; Links, I.H.M.; Warren, N.; Hemmen, J.J. van

2003-01-01

Risk assessment of chemicals requires assessment of the exposure levels of workers. In the absence of adequate specific measured data, models are often used to estimate exposure levels. For dermal exposure only a few models exist, which are not validated externally. In the scope of a large European

Comparative Probabilistic Assessment of Occupational Pesticide Exposures Based on Regulatory Assessments

Science.gov (United States)

Pouzou, Jane G.; Cullen, Alison C.; Yost, Michael G.; Kissel, John C.; Fenske, Richard A.

2018-01-01

Implementation of probabilistic analyses in exposure assessment can provide valuable insight into the risks of those at the extremes of population distributions, including more vulnerable or sensitive subgroups. Incorporation of these analyses into current regulatory methods for occupational pesticide exposure is enabled by the exposure data sets and associated data currently used in the risk assessment approach of the Environmental Protection Agency (EPA). Monte Carlo simulations were performed on exposure measurements from the Agricultural Handler Exposure Database and the Pesticide Handler Exposure Database along with data from the Exposure Factors Handbook and other sources to calculate exposure rates for three different neurotoxic compounds (azinphos methyl, acetamiprid, emamectin benzoate) across four pesticide-handling scenarios. Probabilistic estimates of doses were compared with the no observable effect levels used in the EPA occupational risk assessments. Some percentage of workers were predicted to exceed the level of concern for all three compounds: 54% for azinphos methyl, 5% for acetamiprid, and 20% for emamectin benzoate. This finding has implications for pesticide risk assessment and offers an alternative procedure that may be more protective of those at the extremes of exposure than the current approach. PMID:29105804

Comparative Probabilistic Assessment of Occupational Pesticide Exposures Based on Regulatory Assessments.

Science.gov (United States)

Pouzou, Jane G; Cullen, Alison C; Yost, Michael G; Kissel, John C; Fenske, Richard A

2017-11-06

Implementation of probabilistic analyses in exposure assessment can provide valuable insight into the risks of those at the extremes of population distributions, including more vulnerable or sensitive subgroups. Incorporation of these analyses into current regulatory methods for occupational pesticide exposure is enabled by the exposure data sets and associated data currently used in the risk assessment approach of the Environmental Protection Agency (EPA). Monte Carlo simulations were performed on exposure measurements from the Agricultural Handler Exposure Database and the Pesticide Handler Exposure Database along with data from the Exposure Factors Handbook and other sources to calculate exposure rates for three different neurotoxic compounds (azinphos methyl, acetamiprid, emamectin benzoate) across four pesticide-handling scenarios. Probabilistic estimates of doses were compared with the no observable effect levels used in the EPA occupational risk assessments. Some percentage of workers were predicted to exceed the level of concern for all three compounds: 54% for azinphos methyl, 5% for acetamiprid, and 20% for emamectin benzoate. This finding has implications for pesticide risk assessment and offers an alternative procedure that may be more protective of those at the extremes of exposure than the current approach. © 2017 Society for Risk Analysis.

Challenges and Perspectives of Nanoparticle Exposure Assessment

OpenAIRE

Lee, Ji Hyun; Moon, Min Chaul; Lee, Joon Yeob; Yu, Il Je

2010-01-01

Nanoparticle exposure assessment presents a unique challenge in the field of occupational and environmental health. With the commercialization of nanotechnology, exposure usually starts from the workplace and then spreads to environment and consumer exposure. This report discusses the current trends of nanoparticle exposure assessment, including the definition of nanotechnology relevant terms, essential physicochemical properties for nanomaterial characterization, current international activi...

Assessing population exposures to motor vehicle exhaust.

Science.gov (United States)

Van Atten, Chris; Brauer, Michael; Funk, Tami; Gilbert, Nicolas L; Graham, Lisa; Kaden, Debra; Miller, Paul J; Bracho, Leonora Rojas; Wheeler, Amanda; White, Ronald H

2005-01-01

The need is growing for a better assessment of population exposures to motor vehicle exhaust in proximity to major roads and highways. This need is driven in part by emerging scientific evidence of adverse health effects from such exposures and policy requirements for a more targeted assessment of localized public health impacts related to road expansions and increasing commercial transportation. The momentum for improved methods in measuring local exposures is also growing in the scientific community, as well as for discerning which constituents of the vehicle exhaust mixture may exert greater public health risks for those who are exposed to a disproportionate share of roadway pollution. To help elucidate the current state-of-the-science in exposure assessments along major roadways and to help inform decision makers of research needs and trends, we provide an overview of the emerging policy requirements, along with a conceptual framework for assessing exposure to motor-vehicle exhaust that can help inform policy decisions. The framework includes the pathway from the emission of a single vehicle, traffic emissions from multiple vehicles, atmospheric transformation of emissions and interaction with topographic and meteorologic features, and contact with humans resulting in exposure that can result in adverse health impacts. We describe the individual elements within the conceptual framework for exposure assessment and discuss the strengths and weaknesses of various approaches that have been used to assess public exposures to motor vehicle exhaust.

Kinetics and capacity of repair of sublethal damage in mouse lip mucosa during fractionated irradiations

International Nuclear Information System (INIS)

Ang, K.K.; Xu, F.X.; Landuyt, W.; van der Schueren, E.

1985-01-01

The kinetics and capacity of repair of sublethal damage in mouse lip mucosa have been investigated. To assess the rate of repair 2 and 5 irradiations have been given with intervals ranging from 1 to 24 hours. It was found that the sublethal damage induced by a dose of approximately 10 Gy was fully recovered in approximately 4 hr. After a dose of 5-6 Gy, cellular repair was completed within 3 hr. The half time of repair (T1/2) was estimated to be approximately 72 min for 10 Gy and approximately 54 min for 5-6 Gy. Although these results suggest that the rate of repair is dependent on the fraction size, the possible influence of the amount of repair of sublethal radiation damage with the various fraction sizes used can not be ruled out. To evaluate the capacity of repair, a single dose, 2, 4 and 10 fractions have been given in a maximal overall time of 3 days in order to minimize the influence of repopulation. The slope of the isoeffective curve was 0.32 and the alpha/beta ratio was 8.5 Gy. This indicates that the capacity of cellular repair of lip mucosa is similar to those of other rapidly proliferating tissues but smaller than those of late responding tissues. The results of the present and other studies demonstrate that there are considerable differences in the repair characteristics between acutely and late responding tissues. These features have to be dealt with when fractionation schedules are markedly altered

Critical analysis of the maximum non inhibitory concentration (MNIC) method in quantifying sub-lethal injury in Saccharomyces cerevisiae cells exposed to either thermal or pulsed electric field treatments.

Science.gov (United States)

Kethireddy, V; Oey, I; Jowett, Tim; Bremer, P

2016-09-16

Sub-lethal injury within a microbial population, due to processing treatments or environmental stress, is often assessed as the difference in the number of cells recovered on non-selective media compared to numbers recovered on a "selective media" containing a predetermined maximum non-inhibitory concentration (MNIC) of a selective agent. However, as knowledge of cell metabolic response to injury, population diversity and dynamics increased, the rationale behind the conventional approach of quantifying sub-lethal injury must be scrutinized further. This study reassessed the methodology used to quantify sub-lethal injury for Saccharomyces cerevisiae cells (≈ 4.75 Log CFU/mL) exposed to either a mild thermal (45°C for 0, 10 and 20min) or a mild pulsed electric field treatment (field strengths of 8.0-9.0kV/cm and energy levels of 8, 14 and 21kJ/kg). Treated cells were plated onto either Yeast Malt agar (YM) or YM containing NaCl, as a selective agent at 5-15% in 1% increments. The impact of sub-lethal stress due to initial processing, the stress due to selective agents in the plating media, and the subsequent variation of inhibition following the treatments was assessed based on the CFU count (cell numbers). ANOVA and a generalised least squares model indicated significant effects of media, treatments, and their interaction effects (P<0.05) on cell numbers. It was shown that the concentration of the selective agent used dictated the extent of sub-lethal injury recorded owing to the interaction effects of the selective component (NaCl) in the recovery media. Our findings highlight a potential common misunderstanding on how culture conditions impact on sub-lethal injury. Interestingly for S. cerevisiae cells the number of cells recovered at different NaCl concentrations in the media appears to provide valuable information about the mode of injury, the comparative efficacy of different processing regimes and the inherent degree of resistance within a population. This

Sublethal effects of some synthetic and botanical insecticides on Bemisia tabaci (Hemiptera: Aleyrodidae

Directory of Open Access Journals (Sweden)

Esmaeily Saeideh

2014-07-01

Full Text Available In addition to direct mortality caused by insecticides, some biological traits of insects may also be affected by sublethal insecticide doses. In this study, we used the age-stage, two-sex life table method to evaluate the sublethal effects of the four synthetic insecticides: abamectin, imidacloprid, diazinon, and pymetrozin as well as the botanical insecticide taken from Calotropis procera (Asclepiadaceae extract, on eggs of the cotton whitefly, Bemisia tabaci (Hem.: Aleyrodidae. The lowest and highest survival rates and oviposition periods were observed in whiteflies treated by diazinon and imidacloprid, respectively. We found significant differences in the net reproductive rate (R0, the intrinsic rate of increase (r, the finite rate of increase (?, and the gross reproductive rate (GRR among different insecticides. Altogether, our results showed that pymetrozin and C. procera induced the most sublethal effects, thus they may be suitable candidates for use in integrated pest management programs of B. tabaci.

Health risk assessment of exposure to ionizing radiation

International Nuclear Information System (INIS)

Ogata, Hiromitsu

2011-01-01

Risk assessment is an essential process for evaluating the human health effects of exposure to ionizing radiation and for determining acceptable levels of exposure. There are two major components of radiation risk assessment: a measure of exposure level and a measure of disease occurrence. For quantitative estimation of health risks, it is important to evaluate the association between exposure and disease occurrence using epidemiological or experimental data. In these approaches, statistical risk models are used particularly for estimating cancer risks related to exposure to low levels of radiation. This paper presents a summary of basic models and methods of risk assessment for studying exposure-risk relationships. Moreover, quantitative risk estimates are subject to several sources of uncertainty due to inherent limitations in risk assessment studies. This paper also discusses the limitations of radiation risk assessment. (author)

Evaluation of a biomarker of Cd(II) exposure on Limnoperna fortunei

International Nuclear Information System (INIS)

Mariano, Belaich; Cristian, Oliver; Marcela, Pilloff; Porta, Andres

2006-01-01

The use of organisms to monitor contamination allows the access to information that cannot be acquired by chemical methods. Limnoperna fortunei, mussel frequently found in Rio de la Plata estuary, fulfils the requirements to be used as a biomonitoring organism. In this work we report that a polypeptide of 22 kDa of molecular weight (LF22) is induced when L. fortunei is exposed to Cd (II), Cu(II) and Hg(II) sublethal levels. To characterize LF22, mussels were sampled from a non-polluted region and whole soft tissue was homogenized, with and without previous exposure to 100 μg/L of Cd(II). The cytosolic proteins were evaluated by mono and bidimensional SDS-PAGE, and size exclusion chromatography. All the methods showed that LF22 triples its concentration in presence of Cd(II). Purification of LF22 was achieved by fractioned precipitation, salting-out, ionic exchange and size exclusion chromatography. We conclude that LF22 is a useful biomarker of heavy metal exposure. - Limnoperna fortunei induces a 22 kDa polypeptide in sublethal exposure to Cd(II)

Increased opercular rates of pink salmon (Oncorhynchus gorbuscha) fry after exposure to the eater-soluble fraction of Prudhoe Bay crude oil

Energy Technology Data Exchange (ETDEWEB)

Thomas, R E [Chico State Univ., CA; Rice, S D

1976-01-01

The opercular rates of pink salmon (Oncorhynchus gorbuscha) fry were measured during 24-h exposure to sublethal concentrations of the water-soluble fraction of Prudhoe Bay crude oil. Opercular rates increased significantly for as long as 9 and 12 h after exposure to water-soluble fractions prepared from oil-water solutions of 2.83 and 3.46 ppM. The increases in rates were proportional to increases in dose. Recording changes in opercular rates appears to be a suitable method for detecting sublethal physiological effects of stress, because the observed changes occurred at approximately 20 percent of the 96 h-LC50.

Recurrent sublethal warming reduces embryonic survival, inhibits juvenile growth, and alters species distribution projections under climate change.

Science.gov (United States)

Carlo, Michael A; Riddell, Eric A; Levy, Ofir; Sears, Michael W

2018-01-01

The capacity to tolerate climate change often varies across ontogeny in organisms with complex life cycles. Recently developed species distribution models incorporate traits across life stages; however, these life-cycle models primarily evaluate effects of lethal change. Here, we examine impacts of recurrent sublethal warming on development and survival in ecological projections of climate change. We reared lizard embryos in the laboratory under temperature cycles that simulated contemporary conditions and warming scenarios. We also artificially warmed natural nests to mimic laboratory treatments. In both cases, recurrent sublethal warming decreased embryonic survival and hatchling sizes. Incorporating survivorship results into a mechanistic species distribution model reduced annual survival by up to 24% compared to models that did not incorporate sublethal warming. Contrary to models without sublethal effects, our model suggests that modest increases in developmental temperatures influence species ranges due to effects on survivorship. © 2017 John Wiley & Sons Ltd/CNRS.

The sublethal effects of zinc at different water temperatures on ...

African Journals Online (AJOL)

The sublethal effects of zinc at different water temperatures on selected ... of 96h at different water temperatures representing the seasonal temperatures in the ... are mobilised to meet increased energy demands during periods of stress.

Stress response of the black coral Leiopathes glaberrima when exposed to sub-lethal amounts of crude oil and dispersant

Directory of Open Access Journals (Sweden)

Dannise V. Ruiz-Ramos

2017-12-01

Full Text Available The 2010 Deep Water Horizon oil well failure released billions of gallons of crude oil into the deep Gulf of Mexico, and, combined with chemical dispersants, this oil caused significant coral mortality. However, the mechanisms by which oil and dispersed oil impact deep marine fauna are not well understood. Here, we investigate the effects of oil and dispersed oil on a black coral common in the deep Gulf of Mexico, 'Leiopathes glaberrima. 'This coral occurs in several color morphs that show ecological and genetic differences. We hypothesized that dispersed oil would be more detrimental to coral health than oil alone and that this difference would be detectable in the gene expression response of the colonies even at sub-lethal concentrations. In two experiments, four and six colonies of red and white color morphs were exposed to oil, dispersant, and dispersed oil for a minimum of 96 hours. Visual assessment indicated that indeed dispersant and dispersed oil treatments were more damaging than oil alone, for target concentrations of 25 mg L–1. Decline in health was observed for all treatments, independently of color morphotype, but the decline was faster in the white colonies exposed to dispersant. The responses to the treatments were also investigated by monitoring gene expression after 24 hours of sub-lethal chemical exposure. Coral gene expression differed by chemical stressor. Interestingly, the polycyclic aromatic hydrocarbon biomarker gene, cytochrome P450, was only up-regulated in dispersed oil but not oil alone, suggesting that the dispersant increased the availability of such hydrocarbons in the tissue. The gene expression response was apparent at 24 hours when visual impacts were not (yet detectable. The use of chemical dispersants in oil-spill remediation may cause health declines in deep-water corals and deserves further study.

Does selective logging stress tropical forest invertebrates? Using fat stores to examine sublethal responses in dung beetles.

Science.gov (United States)

França, Filipe; Barlow, Jos; Araújo, Bárbara; Louzada, Julio

2016-12-01

The increased global demand for tropical timber has driven vast expanses of tropical forests to be selectively logged worldwide. While logging impacts on wildlife are predicted to change species distribution and abundance, the underlying physiological responses are poorly understood. Although there is a growing consensus that selective logging impacts on natural populations start with individual stress-induced sublethal responses, this literature is dominated by investigations conducted with vertebrates from temperate zones. Moreover, the sublethal effects of human-induced forest disturbance on tropical invertebrates have never been examined. To help address this knowledge gap, we examined the body fat content and relative abundance of three dung beetle species (Coleoptera: Scarabaeinae) with minimum abundance of 40 individuals within each examined treatment level. These were sampled across 34 plots in a before-after control-impact design (BACI) in a timber concession area of the Brazilian Amazon. For the first time, we present evidence of logging-induced physiological stress responses in tropical invertebrates. Selective logging increased the individual levels of fat storage and reduced the relative abundance of two dung beetle species. Given this qualitative similarity, we support the measurement of body fat content as reliable biomarker to assess stress-induced sublethal effects on dung beetles. Understanding how environmental modification impacts the wildlife has never been more important. Our novel approach provides new insights into the mechanisms through which forest disturbances impose population-level impacts on tropical invertebrates.

Opportunities for using spatial property assessment data in air pollution exposure assessments

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Keller C Peter

2005-10-01

Full Text Available Abstract Background Many epidemiological studies examining the relationships between adverse health outcomes and exposure to air pollutants use ambient air pollution measurements as a proxy for personal exposure levels. When pollution levels vary at neighbourhood levels, using ambient pollution data from sparsely located fixed monitors may inadequately capture the spatial variation in ambient pollution. A major constraint to moving toward exposure assessments and epidemiological studies of air pollution at a neighbourhood level is the lack of readily available data at appropriate spatial resolutions. Spatial property assessment data are widely available in North America and may provide an opportunity for developing neighbourhood level air pollution exposure assessments. Results This paper provides a detailed description of spatial property assessment data available in the Pacific Northwest of Canada and the United States, and provides examples of potential applications of spatial property assessment data for improving air pollution exposure assessment at the neighbourhood scale, including: (1 creating variables for use in land use regression modelling of neighbourhood levels of ambient air pollution; (2 enhancing wood smoke exposure estimates by mapping fireplace locations; and (3 using data available on individual building characteristics to produce a regional air pollution infiltration model. Conclusion Spatial property assessment data are an extremely detailed data source at a fine spatial resolution, and therefore a source of information that could improve the quality and spatial resolution of current air pollution exposure assessments.

Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model.

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Tokiko Ishida

Full Text Available The pathogenesis of renal impairment in chronic liver diseases (CLDs has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy, autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet-fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the

Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

International Nuclear Information System (INIS)

Michalec, François-Gaël; Holzner, Markus; Menu, Dominique; Hwang, Jiang-Shiou; Souissi, Sami

2013-01-01

Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L −1 , cadmium at 45 ng L −1 and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L −1 all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The increase in

Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

Energy Technology Data Exchange (ETDEWEB)

Michalec, François-Gaël [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Holzner, Markus [Institute of Environmental Engineering, ETH Zürich (Switzerland); Menu, Dominique [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); Hwang, Jiang-Shiou [National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Souissi, Sami, E-mail: sami.souissi@univ-lille1.fr [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France)

2013-08-15

Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L{sup −1}, cadmium at 45 ng L{sup −1} and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L{sup −1} all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The

Lethal and sublethal effects of imidacloprid on Osmia lignaria and clothianidin on Megachile rotundata (Hymenoptera: Megachilidae).

Science.gov (United States)

Abbott, V A; Nadeau, J L; Higo, H A; Winston, M L

2008-06-01

We examined lethal and sublethal effects of imidacloprid on Osmia lignaria (Cresson) and clothianidin on Megachile rotundata (F.) (Hymenoptera: Megachilidae). We also made progress toward developing reliable methodology for testing pesticides on wild bees for use in pesticide registration by using field and laboratory experiments. Bee larvae were exposed to control, low (3 or 6 ppb), intermediate (30 ppb), or high (300 ppb) doses of either imidacloprid or clothianidin in pollen. Field experiments on both bee species involved injecting the pollen provisions with the corresponding pesticide. Only O. lignaria was used for the laboratory experiments, which entailed both injecting the bee's own pollen provisions and replacing the pollen provision with a preblended pollen mixture containing imidacloprid. Larval development, emergence, weight, and mortality were monitored and analyzed. There were no lethal effects found for either imidacloprid or clothianidin on O. lignaria and M. rotundata. Minor sublethal effects were detected on larval development for O. lignaria, with greater developmental time at the intermediate (30 ppb) and high doses (300 ppb) of imidacloprid. No similar sublethal effects were found with clothianidin on M. rotundata. We were successful in creating methodology for pesticide testing on O. lignaria and M. rotundata; however, these methods can be improved upon to create a more robust test. We also identified several parameters and developmental stages for observing sublethal effects. The detection of sublethal effects demonstrates the importance of testing new pesticides on wild pollinators before registration.

Absence of bacterial resistance following repeat exposure to photodynamic therapy

Science.gov (United States)

Pedigo, Lisa A.; Gibbs, Aaron J.; Scott, Robert J.; Street, Cale N.

2009-06-01

The prevalence of antibiotic resistant bacteria necessitates exploration of alternative approaches to treat hospital and community acquired infections. The aim of this study was to determine whether bacterial pathogens develop resistance to antimicrobial photodynamic therapy (aPDT) during repeated sub-lethal challenge. Antibiotic sensitive and resistant strains of S. aureus and antibiotic sensitive E. coli were subjected to repeat PDT treatments using a methylene blue photosensitizer formulation and 670 nm illumination from a non-thermal diode laser. Parameters were adjusted such that kills were antibiotic resistance strains. Furthermore, repeated sub-lethal exposure does not induce resistance to subsequent PDT treatments. The absence of resistance formation represents a significant advantage of PDT over traditional antibiotics.

Biochemical parameters in Tubifex tubifex as an integral part of complex sediment toxicity assessment

Energy Technology Data Exchange (ETDEWEB)

Smutna, M.; Hilscherova, K.; Paskova, V. [Masaryk Univ., Brno (CZ). RECETOX (Research Centre for Environmental Chemistry and Ecotoxicology); Marsalek, B [Czech Academy of Science, Brno (Czech Republic). Centre for Cyanobacteria and their Toxins

2008-06-15

Background, aim, and scope Restoration of lakes and reservoirs with extensive cyanobacterial water bloom often requires evaluation of the sediment quality. Next to the chemical analysis of known pollutants, sediment bioassays should be employed to assess toxicity of the present contaminants and to make predictions of associated risk. Brno reservoir in the Czech Republic is a typical example of water bodies with long-term problems concerning cyanobacterial water blooms. Comprehensive assessment of reservoir sediment quality was conducted since successful reservoir restoration might require sediment removal. An important part of this survey focused on an examination of the utility of Tubifex tubifex and its sublethal biochemical markers for the assessment of direct sediment toxicity. Materials and methods This complex study included chemical analysis of contaminants (heavy metals, organic pollutants), ecotoxicity testing of sediment elutriates (tests with Daphnia magna, Pseudomonas putida, Sinapis alba, Scenedesmus subspicatus), and other parameters. We have tested in more detail the applicability of T. tubifex as a test organism for direct evaluation of contact sediment toxicity. Survival tests after 14 days of exposure were complemented by an assessment of parameters serving as biomarkers for sublethal effects [such as total glutathione content (GSH), activities of the enzymes glutathione transferase (GST), glutathione peroxidase (GPx), and glutathione reductase (GR)]. The data matrix was subjected to multivariate analysis to interpret relationships between different parameters and possible differences among locations. Results The multivariate statistical techniques helped to clearly identify the more contaminated upstream sites and separate them from the less contaminated and reference samples. The data document closer relationships of the detected sediment contamination with results of direct sediment exposure in the T. tubifex test regarding mortality but namely

Assessing off-site impacts of wildfires on aquatic organisms using in-situ assays

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Ré, Ana; Saraiva, MariaJoão; Puga, João; Campos, Isabel; Pereira, Joana; Keizer, Jacob; Goncalves, Fernando; Abrantes, Nelson

2017-04-01

Wildfires have been recognized as an important source of diffuse pollution to aquatic systems, particularly through the production and transport of pyrolytic substances such as polycyclic aromatic hydrocarbons (PAHs) and metals associated to ash/soil loads. However, the effects of these compounds from recently burnt areas on the aquatic biota have been largely ignored. Hence, the main goal of this study was to assess the ecotoxicological effects of wildfires in aquatic systems through the use of in situ experiments. In this sense, five sites were selected in a catchment partially burnt: two in the main water course - Ceira river (Miranda do Corvo, Portugal), being one located upstream (RUS) and the other downstream (RDS) the burnt area; two in tributary streams within the burnt area (SUS and SDS); and finally one in a stream located in the unburnt part of the catchment (CS). During the first post-fire rainfall events, distinct organisms, including the water flea Daphnia magna, the freshwater shrimp Atyaephyra desmaresti, the freshwater clam Corbicula fluminea and the mosquitofish Gambusia holbrooki were exposed in situ, in all five sites, using dedicated test chambers. After four days of field exposition, the mortality and post-exposure feeding inhibition were evaluated. Feeding depression after exposure time was selected as a sub-lethal endpoint because it is a quick, sensitive and ecologically relevant indicator of toxic stress. The results showed negligible mortality for all the species and sites, thus lethality was not sensitive to discern impacts among the assessed sites. Conversely, the sub-lethal post-exposure feeding inhibition endpoint, revealed a decrease of feeding rate, in streams within the burnt area (SUS and SDS), that seemed to be the most affected places in the study area. Conversely, the sites outside the burnt area, both on river (RUS) and on the stream (CS), showed no adverse effects in this endpoint. Hence, the current results pointed-out that

Determinants of dermal exposure relevant for exposure modelling in regulatory risk assessment.

Science.gov (United States)

Marquart, J; Brouwer, D H; Gijsbers, J H J; Links, I H M; Warren, N; van Hemmen, J J

2003-11-01

Risk assessment of chemicals requires assessment of the exposure levels of workers. In the absence of adequate specific measured data, models are often used to estimate exposure levels. For dermal exposure only a few models exist, which are not validated externally. In the scope of a large European research programme, an analysis of potential dermal exposure determinants was made based on the available studies and models and on the expert judgement of the authors of this publication. Only a few potential determinants appear to have been studied in depth. Several studies have included clusters of determinants into vaguely defined parameters, such as 'task' or 'cleaning and maintenance of clothing'. Other studies include several highly correlated parameters, such as 'amount of product handled', 'duration of task' and 'area treated', and separation of these parameters to study their individual influence is not possible. However, based on the available information, a number of determinants could clearly be defined as proven or highly plausible determinants of dermal exposure in one or more exposure situation. This information was combined with expert judgement on the scientific plausibility of the influence of parameters that have not been extensively studied and on the possibilities to gather relevant information during a risk assessment process. The result of this effort is a list of determinants relevant for dermal exposure models in the scope of regulatory risk assessment. The determinants have been divided into the major categories 'substance and product characteristics', 'task done by the worker', 'process technique and equipment', 'exposure control measures', 'worker characteristics and habits' and 'area and situation'. To account for the complex nature of the dermal exposure processes, a further subdivision was made into the three major processes 'direct contact', 'surface contact' and 'deposition'.

Probabilistic mercury multimedia exposure assessment in small children and risk assessment.

Science.gov (United States)

Morisset, Typhaine; Ramirez-Martinez, Alejandra; Wesolek, Nathalie; Roudot, Alain-Claude

2013-09-01

Emissions of mercury in the environment have been decreasing for several years. However, mercury species are still found in different media (food, water, air and breast-milk). Due to mercury toxicity and typical behaviour in children, we have conducted a mercury exposure assessment in French babies, and small children aged 0 to 36months. Consumption and mercury concentration data were chosen for the exposure assessment. The Monte Carlo technique has been used to calculate the weekly exposure dose in order to integrate inter-individual variability and parameter uncertainty. Exposure values have been compared to toxicological reference values for health risk assessment. Inorganic mercury median exposure levels ranged from 0.160 to 1.649μg/kg of body weight per week (95th percentile (P95): 0.298-2.027µg/kg bw/week); elemental mercury median exposure level in children was 0.11ng/kg bw/week (P95: 28ng/kg bw/week); and methylmercury median exposure level ranged from 0.247 to 0.273µg/kg bw/week (P95: 0.425-0.463µg/kg bw/week). Only elemental mercury by inhalation route (indoor air) and methylmercury by ingestion (fish and breast-milk) seem to lead to a health risk in small children. These results confirm the importance of assessing total mercury concentration in media like breast-milk, indoor air and dust and methylmercury level in food, other than fish and seafood. In this way, informed monitoring plan and risk assessment in an at-risk sub-population can be set. © 2013 Elsevier Ltd. All rights reserved.

EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

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Wan Fatma ZUHARAH

2016-01-01

Full Text Available Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity and eggs hatchability (fertility in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors.

Avoidance behaviour and anxiety in rats irradiated with a sublethal dose of gamma-rays.

Science.gov (United States)

Tomášová, Lenka; Smajda, B; Bona, M

2011-12-01

The aim of this study was to assess, whether a sublethal dose of gamma-rays will influence the avoidance behaviour and anxiety in rats and whether the response to radiation depends on time of day of its application. Adult male Wistar rats were tested in elevated plus-maze, in hot plate test and in the light/dark box in 4 regular intervals during a day. After two weeks the animals were irradiated with a whole-body dose 6 Gy of gamma-rays. One day after irradiation the animals were repeatedly tested in the same way, as before irradiation. In the plus-maze test an increased level of anxiety was established. The irradiation significantly decreased the locomotor activity of rats, but the extent of exploratory and comfortable behaviour were not altered. After irradiation, an elevated aversion to the thermal stimulus was observed in the hot plate test. The effects of radiation were more pronounced in the light period of the day, than in the dark one. No significant differences in aversion to light were detected after irradiation. The obtained results indicate, that sublethal doses of ionizing radiation can markedly influence the reactivity of animals to adverse stimuli, their motoric activity and emotional status, as well.

Effects of sublethal doses of chlorfluazuron on the ovarian ...

African Journals Online (AJOL)

AJB_YOMI

2011-10-12

Oct 12, 2011 ... eggs (Perveen, 2000a). The objectives of this research were to determine the effects of sublethal doses of chlorfluazuron (LD10or LD30) on the amounts of ovarianprotein, lipid, carbohydrates, DNA, and RNA, and ecdysteroid titres in different developmental stages of S. litura, a major crop pest around the ...

Sub-lethal effects of pesticide residues in brood comb on worker honey bee (Apis mellifera development and longevity.

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Judy Y Wu

Full Text Available BACKGROUND: Numerous surveys reveal high levels of pesticide residue contamination in honey bee comb. We conducted studies to examine possible direct and indirect effects of pesticide exposure from contaminated brood comb on developing worker bees and adult worker lifespan. METHODOLOGY/PRINCIPAL FINDINGS: Worker bees were reared in brood comb containing high levels of known pesticide residues (treatment or in relatively uncontaminated brood comb (control. Delayed development was observed in bees reared in treatment combs containing high levels of pesticides particularly in the early stages (day 4 and 8 of worker bee development. Adult longevity was reduced by 4 days in bees exposed to pesticide residues in contaminated brood comb during development. Pesticide residue migration from comb containing high pesticide residues caused contamination of control comb after multiple brood cycles and provided insight on how quickly residues move through wax. Higher brood mortality and delayed adult emergence occurred after multiple brood cycles in contaminated control combs. In contrast, survivability increased in bees reared in treatment comb after multiple brood cycles when pesticide residues had been reduced in treatment combs due to residue migration into uncontaminated control combs, supporting comb replacement efforts. Chemical analysis after the experiment confirmed the migration of pesticide residues from treatment combs into previously uncontaminated control comb. CONCLUSIONS/SIGNIFICANCE: This study is the first to demonstrate sub-lethal effects on worker honey bees from pesticide residue exposure from contaminated brood comb. Sub-lethal effects, including delayed larval development and adult emergence or shortened adult longevity, can have indirect effects on the colony such as premature shifts in hive roles and foraging activity. In addition, longer development time for bees may provide a reproductive advantage for parasitic Varroa destructor

Sublethal effects of four insecticides on folding and spinning behavior in the rice leaffolder, Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae).

Science.gov (United States)

Yang, Yajun; Wang, Caiyun; Xu, Hongxing; Lu, Zhongxian

2018-03-01

The rice leaffolder, Cnaphalocrocis medinalis, is an important rice pest. The sublethal effects of chlorpyrifos, chlorantraniliprole, emamectin benzoate and spinosad were investigated on the folding and spinning behaviors of third- to fifth-instar C. medinalis larvae (L3 - L5) after insecticidal exposure of the second instar. A 25% lethal concentration (LC 25 ) of chlorpyrifos prolonged the leaf selection time of L5, and reduced the number of binds per primary fold for L4 and L5. An LC 10 of chlorantraniliprole reduced the number of binds per primary fold for L4 and increased the number of head swings per bind for L5. An LC 10 of emamectin benzoate shortened the primary fold length for L5 and decreased the number of head swings per primary fold for L3 and L4 and the number of head swings per bind for L3, while an LC 25 of emamectin benzoate shortened the fold length per 24 h for L5 and folding time for L3. An LC 10 of spinosad lowered the fold length per 24 h and the number of head swings for L5. An LC 25 of spinosad prolonged leaf selection time, and decreased primary fold length, binds per primary fold, binds per fold and fold length per 24 h in L5. Emamectin benzoate and spinosad exerted stronger sublethal effects on the folding and spinning behavior of C. medinalis than chlorpyrifos and chlorantraniliprole. These results provide better understanding of the sublethal effects of interactions of insecticides on C. medinalis. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Toxicity of thiamethoxam to Tetranychus urticae Koch and Phytoseiulus persimilis Athias-Henriot (Acari Tetranychidae, Phytoseiidae) through different routes of exposure.

Science.gov (United States)

Pozzebon, Alberto; Duso, Carlo; Tirello, Paola; Ortiz, Paulina Bermudez

2011-03-01

Knowledge of the impact of insecticides on Tetranychus urticae Koch and its predator Phytoseiulus persimilis Athias-Henriot is crucial for IPM. This study evaluates the effect of thiamethoxam on T. urticae and its predator by considering different routes of exposure (topical, residual and contaminated food exposures) and their combinations. Thiamethoxam effects on T. urticae were higher when residual and contaminated food exposures were considered. The total effect was higher than 90% where contaminated food exposure was involved. On P. persimilis, the total effect was higher in residual and contaminated prey exposures compared with topical exposure, and all combinations of routes of exposure attained a total effect higher than 90%. Thiamethoxam was found to be toxic to T. urticae and P. persimilis; however, the impact of the insecticide depended on the routes of exposure and their combinations. Lethal and sublethal effects occurred in residual and contaminated food exposures, while only sublethal effects occurred in topical exposure of predators and prey. The toxicity of thiamethoxam on prey and predator increased with the number of exposure routes involved. By limiting exposure to thiamethoxam to ingestion of contaminated food only, the impact of the pesticide was more favourable to P. persimilis than to its prey. Copyright © 2010 Society of Chemical Industry.

Human exposure assessment to environmental chemicals using biomonitoring.

Science.gov (United States)

Calafat, Antonia M; Ye, Xiaoyun; Silva, Manori J; Kuklenyik, Zsuzsanna; Needham, Larry L

2006-02-01

In modern societies, humans may be exposed to a wide spectrum of environmental chemicals. Although the health significance of this exposure for many chemicals is unknown, studies to investigate the prevalence of exposure are warranted because of the chemicals' potential harmful health effects, as often indicated in animal studies. Three tools have been used to assess exposure: exposure history/questionnaire information, environmental monitoring, and biomonitoring (i.e. measuring concentrations of the chemicals, their metabolites, or their adducts in human specimens). We present an overview on the use of biomonitoring in exposure assessment using phthalates, bisphenol A and other environmental phenols, and perfluorinated chemicals as examples. We discuss some factors relevant for interpreting and understanding biomonitoring data, including selection of both biomarkers of exposure and human matrices, and toxicokinetic information. The use of biomonitoring in human risk assessment is not discussed.

Sub-lethal effects of the neurotoxic pyrethroid insecticide Fastac 50EC on the general motor and locomotor activities of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae).

Science.gov (United States)

Tooming, Ene; Merivee, Enno; Must, Anne; Sibul, Ivar; Williams, Ingrid

2014-06-01

Sub-lethal effects of pesticides on behavioural endpoints are poorly studied in carabids (Coleoptera: Carabidae) though changes in behaviour caused by chemical stress may affect populations of these non-targeted beneficial insects. General motor activity and locomotion are inherent in many behavioural patterns, and changes in these activities that result from xenobiotic influence mirror an integrated response of the insect to pesticides. Influence of pyrethroid insecticides over a wide range of sub-lethal doses on the motor activities of carabids still remains unclear. Video tracking of Platynus assimilis showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations ranged from 0.01 to 100 mg L(-1) caused initial short-term (24 h) locomotor hypo-activity. In addition, significant short- and long-term concentration and time-dependent changes occurred in general motor activity patterns and rates. Conspicuous changes in motor activity of Platynus assimilis beetles treated at alpha-cypermethrin concentrations up to 75,000-fold lower than maximum field recommended concentration (MFRC) suggest that many, basic fitness-related behaviours might be severely injured as well. These changes may negatively affect carabid populations in agro-ecosystems. Long-term hypo-activity could directly contribute to decreased trap captures of carabids frequently observed after insecticide application in the field. © 2013 Society of Chemical Industry.

Retrospective Occupational Exposure Assessment in Community-Based Studies Made Easier

International Nuclear Information System (INIS)

Fritschi, L.; Girschik, J.; Friesen, M.C.; Glass, D.; Monash, G.B.; Sadkowsky, T.

2010-01-01

Occ DEAS Assessing occupational exposure in retrospective community-based case-control studies is difficult as measured exposure data are very seldom available. The expert assessment method is considered the most accurate way to attribute exposure but it is a time consuming and expensive process and may be seen as subjective, non reproducible, and non transparent. In this paper, we describe these problems and outline our solutions as ope rationalized in a web-based software application (Occ DEAS). The novel aspects of Occ DEAS are combining all steps in the assessment into one software package; enmeshing the process of assessment into the development of questionnaires; selecting the exposure(s) of interest; specifying rules for exposure assignment; allowing manual or automatic assessments; ensuring that circumstances in which exposure is possible for an individual are highlighted for review; providing reports to ensure consistency of assessment. Development of this application has the potential to make high-quality occupational assessment more efficient and accessible for epidemiological studies

Assessment of Skin Pathological Responses in the Yellowfin Seabream (Acanthopagrus latus under the Aeromonas hydrophila Exposure

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Fatemeh Azadbakht

2018-01-01

Full Text Available Background: Bacterial diseases in cultured fish are considered the main problem to aquaculture system. Skin is the structure that covers the body in fish. Skin histopatological alterations were used to assess the effects of Aeromonas hydrophila exposure on the yellowfin seabream Acanthopagrus latus(. Methods: In this regard, 90 A. latus were exposed to sublethal concentrations of A. hydrophila (103,106 CFU/ml for 3 weeks. Results: Some more severe alternations found in the skin of fish exposed. The most frequent histopathological changes detected in the skin including hyperplasia of epidermis, hypertrophy and hyperplasia of the mucosal cells and dermis edema. Some more severe alternations found in the skin of fish exposed to higher level of A. hydrophila (106 CFU/ml included telangiectasia of dermis layer. In addition, according to the results of histometrical studies in treated fish compared to control group showed that thickness of epidermis and dermis layers were increased significantly (P<0.05. Conclusion: A. hydrophila can cause major histophatological changes in the skin of A. latus. In addition, histopathological changes of the skin provide helpful information about the environmental conditions and as particular biomarkers may provide imminent into evaluating the general health and stress status of fish.

Assessment of predictive dermal exposure to chemicals in the work environment

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Agnieszka Jankowska

2017-08-01

Full Text Available Assessment of dermal exposure to chemicals in the work environment is problematic, mainly as a result of the lack of measurement data on occupational exposure to chemicals. Due to common prevalence of occupational skin exposure and its health consequences it is necessary to look for efficient solutions allowing for reliable exposure assessment. The aim of the study is to present predictive models used to assess non-measured dermal exposure, as well as to acquaint Polish users with the principles of the selected model functioning. This paper presents examples of models to assist the employer in the the assessment of occupational exposure associated with the skin contact with chemicals, developed in European Union (EU countries, as well as in countries outside the EU. Based on the literature data dermal exposure models EASE (Estimation and Assessment of Substance Exposure, COSHH Essentials (Control of Substances Hazardous to Health Regulations, DREAM (Dermal Exposure Assessment Method, Stoffenmanager , ECETOC TRA (European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment, MEASE (Metal’s EASE, PHED (Pesticide Handlers Exposure Database, DERM (Dermal Exposure Ranking Method and RISKOFDERM (Risk Assessment of Occupational Dermal Exposure to Chemicals were briefly described. Moreover the characteristics of RISKOFDERM, guidelines for its use, information on input and output data were further detailed. Problem of full work shift dermal exposure assessment is described. An example of exposure assessment using RISKOFDERM and effectiveness evaluation to date were also presented. When no measurements are available, RISKOFDERM allows dermal exposure assessment and thus can improve the risk assessment quality and effectiveness of dermal risk management. Med Pr 2017;68(4:557–569

Wishful Thinking? Inside the Black Box of Exposure Assessment.

Science.gov (United States)

Money, Annemarie; Robinson, Christine; Agius, Raymond; de Vocht, Frank

2016-05-01

Decision-making processes used by experts when undertaking occupational exposure assessment are relatively unknown, but it is often assumed that there is a common underlying method that experts employ. However, differences in training and experience of assessors make it unlikely that one general method for expert assessment would exist. Therefore, there are concerns about formalizing, validating, and comparing expert estimates within and between studies that are difficult, if not impossible, to characterize. Heuristics on the other hand (the processes involved in decision making) have been extensively studied. Heuristics are deployed by everyone as short-cuts to make the often complex process of decision-making simpler, quicker, and less burdensome. Experts' assessments are often subject to various simplifying heuristics as a way to reach a decision in the absence of sufficient data. Therefore, investigating the underlying heuristics or decision-making processes involved may help to shed light on the 'black box' of exposure assessment. A mixed method study was conducted utilizing both a web-based exposure assessment exercise incorporating quantitative and semiqualitative elements of data collection, and qualitative semi-structured interviews with exposure assessors. Qualitative data were analyzed using thematic analysis. Twenty-five experts completed the web-based exposure assessment exercise and 8 of these 25 were randomly selected to participate in the follow-up interview. Familiar key themes relating to the exposure assessment exercise emerged; 'intensity'; 'probability'; 'agent'; 'process'; and 'duration' of exposure. However, an important aspect of the detailed follow-up interviews revealed a lack of structure and order with which participants described their decision making. Participants mostly described some form of an iterative process, heavily relying on the anchoring and adjustment heuristic, which differed between experts. In spite of having undertaken

Perspectives for integrating human and environmental exposure assessments.

Science.gov (United States)

Ciffroy, P; Péry, A R R; Roth, N

2016-10-15

Integrated Risk Assessment (IRA) has been defined by the EU FP7 HEROIC Coordination action as "the mutual exploitation of Environmental Risk Assessment for Human Health Risk Assessment and vice versa in order to coherently and more efficiently characterize an overall risk to humans and the environment for better informing the risk analysis process" (Wilks et al., 2015). Since exposure assessment and hazard characterization are the pillars of risk assessment, integrating Environmental Exposure assessment (EEA) and Human Exposure assessment (HEA) is a major component of an IRA framework. EEA and HEA typically pursue different targets, protection goals and timeframe. However, human and wildlife species also share the same environment and they similarly inhale air and ingest water and food through often similar overlapping pathways of exposure. Fate models used in EEA and HEA to predict the chemicals distribution among physical and biological media are essentially based on common properties of chemicals, and internal concentration estimations are largely based on inter-species (i.e. biota-to-human) extrapolations. Also, both EEA and HEA are challenged by increasing scientific complexity and resources constraints. Altogether, these points create the need for a better exploitation of all currently existing data, experimental approaches and modeling tools and it is assumed that a more integrated approach of both EEA and HEA may be part of the solution. Based on the outcome of an Expert Workshop on Extrapolations in Integrated Exposure Assessment organized by the HEROIC project in January 2014, this paper identifies perspectives and recommendations to better harmonize and extrapolate exposure assessment data, models and methods between Human Health and Environmental Risk Assessments to support the further development and promotion of the concept of IRA. Ultimately, these recommendations may feed into guidance showing when and how to apply IRA in the regulatory decision

Exposure Assessment Tools by Lifestages and Populations - General Population

Science.gov (United States)

EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

Safety assessments for potential exposures

International Nuclear Information System (INIS)

Dunn, D.I.

2012-04-01

Safety Assessment of potential exposures have been carried out in major practices, namely: industrial radiography, gamma irradiators and electron accelerators used in industry and research, and radiotherapy. This paper focuses on reviewing safety assessment methodologies and using developed software to analyse radiological accidents, also review, and discuss these past accidents.The primary objective of the assessment is to assess the adequacy of planned or existing measures for protection and safety and to identify any additional measures that should be put in place. As such, both routine use of the source and the probability and magnitude of potential exposures arising from accidents or incidents should be considered. Where the assessment indicates that there is a realistic possibility of an accident affecting workers or members of the public or having consequences for the environment, the registrant or licensee should prepare a suitable emergency plan. A safety assessment for normal operation addresses all the conditions under which the radiation source operates as expected, including all phases of the lifetime of the source. Due account needs to be taken of the different factors and conditions that will apply during non-operational phases, such as installation, commissioning and maintenance. (author)

Intramuscular Cobinamide Sulfite in a Rabbit Model of Sub-Lethal Cyanide Toxicity

Science.gov (United States)

Brenner, Matthew; Kim, Jae G.; Mahon, Sari B.; Lee, Jangwoen; Kreuter, Kelly A.; Blackledge, William; Mukai, David; Patterson, Steve; Mohammad, Othman; Sharma, Vijay S.; Boss, Gerry R.

2009-01-01

Objective To determine the ability of an intramuscular cobinamide sulfite injection to rapidly reverse the physiologic effects of cyanide toxicity. Background Exposure to cyanide in fires and industrial exposures and intentional cyanide poisoning by terrorists leading to mass casualties is an ongoing threat. Current treatments for cyanide poisoning must be administered intravenously, and no rapid treatment methods are available for mass casualty cyanide exposures. Cobinamide is a cobalamin (vitamin B12) analog with an extraordinarily high affinity for cyanide that is more water-soluble than cobalamin. We investigated the use of intramuscular cobinamide sulfite to reverse cyanide toxicity induced physiologic changes in a sublethal cyanide exposure animal model. Methods New Zealand white rabbits were given 10 mg sodium cyanide intravenously over 60 minutes. Quantitative diffuse optical spectroscopy and continuous wave near infrared spectroscopy monitoring of tissue oxy- and deoxyhemoglobin concentrations were performed concurrently with blood cyanide level measurements and cobinamide levels. Immediately after completion of the cyanide infusion, the rabbits were injected intramuscularly with cobinamide sulfite (n=6) or inactive vehicle (controls, n=5). Results Intramuscular administration led to rapid mobilization of cobinamide and was extremely effective at reversing the physiologic effects of cyanide on oxyhemoglobin and deoxyhemoglobin extraction. Recovery time to 63% of their baseline values in the central nervous system was in a mean of 1032 minutes in the control group and 9 minutes in the cobinamide group with a difference of 1023 minutes (95% confidence interval [CI] 116, 1874 minutes). In muscle tissue, recovery times were 76 and 24 minutes with a difference of 52 minutes (95% CI 7, 98min). Red blood cell cyanide levels returned towards normal significantly faster in cobinamide sulfite-treated animals than in control animals. Conclusions Intramuscular

Using photopigment biomarkers to quantify sub-lethal effects of petroleum pollution on natural phytoplankton assemblages

International Nuclear Information System (INIS)

Swistak, J.; Pinckney, J.; Piehler, M.; Paerl, H.

1995-01-01

Although much work has been undertaken to determine the toxicity of petroleum pollutants to phytoplankton, most studies have used pure cultures to monitor growth of selected phytoplankton species. Fewer have considered the net effect on entire microalgal communities. Using high performance liquid chromatography (HPLC) to characterize diagnostic microalgal pigments, the authors were able to simultaneously assess sub-lethal pollutant effects on entire communities as well as on individual phytoplankton functional groups. Incubations of natural water samples with diesel fuel, an important contributor to coastal petroleum pollution, revealed significant changes in photopigments and relative abundance of taxonomic groups at sub-lethal concentrations. Differential rates of change of indicator pigment concentrations suggest a range of sensitivity among phytoplankton groups. In preliminary experiments, cyanobacteria exhibited the greatest overall tolerance to the diesel fuel concentrations tested, while cryptomonads displayed the most sensitivity. The authors are currently evaluating the responses of seasonal phytoplankton populations from 3 sites exposed to varied levels of petroleum pollution. HPLC will be used to characterize phytoplankton populations and to determine if the most abundant groups are also the most tolerant of diesel fuel. Preliminary experiments indicate that diesel fuel pollution may modify the structure and function of phytoplankton communities and subsequently alter the trophodynamics of impacted systems

Sublethal Effects of Beauveria bassiana (Ascomycota: Hypocreales) on Life Table Parameters of Frankliniella occidentalis (Thysanoptera: Thripidae).

Science.gov (United States)

Zhang, Tao; Reitz, Stuart R; Wang, Haihong; Lei, Zhongren

2015-06-01

We assessed effects of parental exposure to Beauveria bassiana on life history traits of subsequent generations of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Progeny from individuals that survived fungal exposure as second instars had significantly shorter egg stages, but longer prepupal development times than corresponding untreated controls. However, survivorship to adulthood of these progeny groups did not differ. Although fecundities of the parental types did not differ, the sex ratio of progeny from fungal-treated parents was male-biased, whereas sex ratio of progeny from untreated control parents was even. We calculated life table parameters for the progeny and found that all parameters, except for generation time, were significantly less for the progeny of fungal-treated parents than for progeny of untreated parents. The intrinsic rate of increase, finite rate of increase, net reproductive rate, mean generation time, and gross reproductive rate were 0.199 d(-1), 1.229 d(-1), 21.84, 15.48 d, and 27.273, respectively, for progeny of treated thrips, and 0.266 d(-1), 1.316 d(-1), 52.540, 14.92 d, and 70.64, respectively, for progeny of control thrips. Consequently, population projections demonstrated that offspring of parents exposed to B. bassiana would increase their population more slowly than those from untreated parents. These results demonstrate that B. bassiana has sublethal effects that reduce the reproductive success of F. occidentalis and these effects should be taken into account when evaluating its use in management programs for F. occidentalis. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sublethal effects of clothianidin and Nosema spp. on the longevity and foraging activity of free flying honey bees.

Science.gov (United States)

Odemer, Richard; Nilles, Lisa; Linder, Nadine; Rosenkranz, Peter

2018-03-19

Neonicotinoids alone or in combination with pathogens are considered to be involved in the worldwide weakening of honey bees. We here present a new approach for testing sublethal and/or synergistic effects in free flying colonies. In our experiment individually marked honey bees were kept in free flying mini-hives and chronically exposed to sublethal doses of the neonicotinoid clothianidin. Additional groups of bees were challenged with Nosema infections or with combinations of the pesticide and pathogens. Longevity and flight activity of the differentially treated bees were monitored for a period of 18 days. In contrast to previous laboratory studies, no effect of the neonicotinoid treatment on mortality or flight activity could be observed. Although the lifespan of Nosema infected bees were significantly reduced compared to non-infected bees a combination of pesticide and pathogen did not reveal any synergistic effect. Our results indicate that individual bees are less impaired by neonicotinoids if kept within the social environment of the colony. The effect of such a "social buffering" should be considered in future risk assessments.

Sublethal effects of herbicides on the biomass and seed production of terrestrial non-crop plant species, influenced by environment, development stage and assessment date

International Nuclear Information System (INIS)

Riemens, Marleen M.; Dueck, Thom; Kempenaar, Corne; Lotz, Lambertus A.P.; Kropff, Martin J.J.

2009-01-01

Guidelines provided by the OECD and EPPO allow the use of single-species tests performed in greenhouses to assess the risk of herbicides to non-target terrestrial plant communities in the field. The present study was undertaken to investigate the use of greenhouse data to determine effects of herbicides with a different mode of action on the biomass, seed production and emergence of field-grown plants. In addition, a single species approach was compared with a mixed species approach. Effects on the biomass of greenhouse and field-grown plants were found to be related at different effect levels, indicating that it might be possible to translate results from greenhouse studies to field situations. However, the use of single-species tests may not be valid. The response of a single plant species to sublethal herbicide dosages differed to the response of the same species grown in a mixture with other species. - The use of single-species greenhouse tests in the ecological risk assessment of crop protection products may only be valid for single species in the field, not for vegetations.

Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints

Energy Technology Data Exchange (ETDEWEB)

Sala, Miquel [Centre Tecnològic Forestal de Catalunya - CTFC, Solsona, Catalunya (Spain); Faria, Melissa [CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Sarasúa, Ignacio [Technische Universität München, Munich, Bayern (Germany); Barata, Carlos [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona (Spain); Bonada, Núria [Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Catalonia (Spain); Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona - UB, Diagonal 643, 08028 Barcelona, Catalonia (Spain); Brucet, Sandra [Aquatic Ecology Group, BETA Tecnio Centre, University of Vic - Central University of Catalonia, Vic, Catalonia (Spain); Catalan Institution for Research and Advanced Studies, ICREA, Barcelona 08010 (Spain); Llenas, Laia; Ponsá, Sergio [Aquatic Ecology Group, BETA Tecnio Centre, University of Vic - Central University of Catalonia, Vic, Catalonia (Spain); Prat, Narcís [Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Catalonia (Spain); Soares, Amadeu M.V.M. [CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); and others

2016-10-01

The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl{sup −} and SO{sub 4}{sup 2−}) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5 mS cm{sup −1}) with Cl{sup −}:SO{sub 4}{sup 2−} ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48 h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators

Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints

International Nuclear Information System (INIS)

Sala, Miquel; Faria, Melissa; Sarasúa, Ignacio; Barata, Carlos; Bonada, Núria; Brucet, Sandra; Llenas, Laia; Ponsá, Sergio; Prat, Narcís; Soares, Amadeu M.V.M.

2016-01-01

The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl"− and SO_4"2"−) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5 mS cm"−"1) with Cl"−:SO_4"2"− ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48 h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators. - Highlights: • We assessed Cl

Progress in human exposure assessment for biocidal products

NARCIS (Netherlands)

Hemmen, J.J. van

2004-01-01

An important shortcoming in our present knowledge required for risk assessment of biocidal products is the assessment of human exposure. This knowledge gap has been filled in a preliminary fashion with the TNsG on human exposure to biocidal products (available from the ECB website). Explicit User

Assessment of chemical exposures: calculation methods for environmental professionals

National Research Council Canada - National Science Library

Daugherty, Jack E

1997-01-01

... on by scientists, businessmen, and policymakers. Assessment of Chemical Exposures: Calculation Methods for Environmental Professionals addresses the expanding scope of exposure assessments in both the workplace and environment...

Risk assessment and management of radiofrequency radiation exposure

Energy Technology Data Exchange (ETDEWEB)

Dabala, Dana [Railways Medical Clinic Cluj-Napoca, Occupational Medicine Department, 16-20 Bilascu Gheorghe St., 400015 Cluj-Napoca (Romania); Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath St., 400293 Cluj-Napoca (Romania)

2013-11-13

Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

Risk assessment and management of radiofrequency radiation exposure

International Nuclear Information System (INIS)

Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

2013-01-01

Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management

Human exposure to bisphenol A by biomonitoring: Methods, results and assessment of environmental exposures

International Nuclear Information System (INIS)

Dekant, Wolfgang; Voelkel, Wolfgang

2008-01-01

Human exposure to bisphenol A is controversially discussed. This review critically assesses methods for biomonitoring of bisphenol A exposures and reported concentrations of bisphenol A in blood and urine of non-occupationally ('environmentally') exposed humans. From the many methods published to assess bisphenol A concentrations in biological media, mass spectrometry-based methods are considered most appropriate due to high sensitivity, selectivity and precision. In human blood, based on the known toxicokinetics of bisphenol A in humans, the expected very low concentrations of bisphenol A due to rapid biotransformation and the very rapid excretion result in severe limitations in the use of reported blood levels of bisphenol A for exposure assessment. Due to the rapid and complete excretion of orally administered bisphenol A, urine samples are considered as the appropriate body fluid for bisphenol A exposure assessment. In urine samples from several cohorts, bisphenol A (as glucuronide) was present in average concentrations in the range of 1-3 μg/L suggesting that daily human exposure to bisphenol A is below 6 μg per person (< 0.1 μg/kg bw/day) for the majority of the population

The growth and development of Schistosoma mansoni in mice exposed to sublethal doses of radiation

International Nuclear Information System (INIS)

Aitken, R.; Wilson, R.A.

1989-01-01

The maturation of Schistosoma mansoni was studied in mice exposed to various sublethal doses of radiation. Although the treatment of mice with 500 rads of radiation prior to infection did not alter parasite maturation, doses in excess of 500 rads led to a reduction in worm burden. This could not be attributed to a delay in the arrival of parasites in the hepatic portal system. Worms developing in mice treated with 800 rads commenced egg-laying about 1 wk later than worms in intact mice, and the rate of egg deposition appeared to be lower in irradiated hosts. The data demonstrate that exposure of C57BL/6 mice to doses of radiation in excess of 500 rads impairs their ability to carry infections of S. mansoni. The findings do not support the hypothesis that primary worm burdens in the mouse are controlled by a host immune response

Anticoagulant rodenticide toxicity to non-target wildlife under controlled exposure conditions

Science.gov (United States)

Rattner, Barnett A.; Mastrota, F. Nicholas; van den Brink, Nico; Elliott, J.; Shore, R.; Rattner, B.

2018-01-01

-target wildlife. Ecological risk assessments of anticoagulant rodenticides would be improved with additional data on (i) interspecific differences in sensitivity, particularly for understudied taxa, (ii) sublethal effects unrelated to coagulopathy, (iii) responses to mixtures and sequential exposures, and (iv) the role of vitamin K status on toxicity, and significance of inclusion of supplemental vitamin K or menadione (provitamin) in the diet of test organisms. A more complete understanding of the toxicity of anticoagulant rodenticides in non-target wildlife would enable regulators and natural resource managers to better predict and even mitigate risk.

Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium

Directory of Open Access Journals (Sweden)

Lawrence Ikechukwu Ezemonye

2011-12-01

Full Text Available Adult Bufo maculatus was exposed to sublethal cadmium concentrations of 0.25, 0.50, 1.00 and 2.00 mg/L. The toxicant from which the cadmium concentrations were prepared was cadmium chloride (CdCl2.H2O. There were three replicate tanks per treatment and three individuals per tank including control groups. The hematologic alterations based on the examination of blood indices during the 28 days of exposure showed that total erythrocyte count (TEC, hematocrit (Hct and hemoglobin (Hb concentration decreased (P<0.05 relative to controls. The decline was concentration- dependent as concentration of cadmium increased. The decline in hemoglobin and hematocrit in the experimental organism could be due to a decrease in the synthesis or release of erythrocytes into the circulation or an increase in the rate of erythrocyte destruction inflicted by cadmium toxicity. There was significant (P<0.05 elevation in total leuko- leukocyte count (TLC with increase in the concen- cyte concentration of cadmium. The increase in total leukocyte count observed in this study could be attributed to a stimulation of the immune system in response to tissue damage caused by cadmium toxicity. The study has shown that the exposure of the Bufo maculatus toad to cadmium can inflict alterations in the hematologic indices, which could induce unfavorable physiological changes in the amphibian, which may lead to death. There is, therefore, the need to protect amphibians in order to sustain the biodiversity in the Nigerian Niger Delta ecological zone.

Respiratory hazard assessment of combined exposure to complete gasoline exhaust and respirable volcanic ash in a multicellular human lung model at the air-liquid interface.

Science.gov (United States)

Tomašek, Ines; Horwell, Claire J; Bisig, Christoph; Damby, David E; Comte, Pierre; Czerwinski, Jan; Petri-Fink, Alke; Clift, Martin J D; Drasler, Barbara; Rothen-Rutishauser, Barbara

2018-07-01

Communities resident in urban areas located near active volcanoes can experience volcanic ash exposures during, and following, an eruption, in addition to sustained exposures to high concentrations of anthropogenic air pollutants (e.g., vehicle exhaust emissions). Inhalation of anthropogenic pollution is known to cause the onset of, or exacerbate, respiratory and cardiovascular diseases. It is further postulated similar exposure to volcanic ash can also affect such disease states. Understanding of the impact of combined exposure of volcanic ash and anthropogenic pollution to human health, however, remains limited. The aim of this study was to assess the biological impact of combined exposure to respirable volcanic ash (from Soufrière Hills volcano (SHV), Montserrat and Chaitén volcano (ChV), Chile; representing different magmatic compositions and eruption styles) and freshly-generated complete exhaust from a gasoline vehicle. A multicellular human lung model (an epithelial cell-layer composed of A549 alveolar type II-like cells complemented with human blood monocyte-derived macrophages and dendritic cells cultured at the air-liquid interface) was exposed to diluted exhaust (1:10) continuously for 6 h, followed by immediate exposure to the ash as a dry powder (0.54 ± 0.19 μg/cm 2 and 0.39 ± 0.09 μg/cm 2 for SHV and ChV ash, respectively). After an 18 h incubation, cells were exposed again for 6 h to diluted exhaust, and a final 18 h incubation (at 37 °C and 5% CO 2 ). Cell cultures were then assessed for cytotoxic, oxidative stress and (pro-)inflammatory responses. Results indicate that, at all tested (sub-lethal) concentrations, co-exposures with both ash samples induced no significant expression of genes associated with oxidative stress (HMOX1, NQO1) or production of (pro-)inflammatory markers (IL-1β, IL-8, TNF-α) at the gene and protein levels. In summary, considering the employed experimental conditions, combined exposure of

Respiratory hazard assessment of combined exposure to complete gasoline exhaust and respirable volcanic ash in a multicellular human lung model at the air-liquid interface

Science.gov (United States)

Tomasek, Ines; Horwell, Claire J.; Bisig, Christoph; Damby, David; Comte, Pierre; Czerwinski, Jan; Petri-Fink, Alke; Clift, Martin J D; Drasler, Barbara; Rothen-Rutishauer, Barbara

2018-01-01

Communities resident in urban areas located near active volcanoes can experience volcanic ash exposures during, and following, an eruption, in addition to sustained exposures to high concentrations of anthropogenic air pollutants (e.g., vehicle exhaust emissions). Inhalation of anthropogenic pollution is known to cause the onset of, or exacerbate, respiratory and cardiovascular diseases. It is further postulated similar exposure to volcanic ash can also affect such disease states. Understanding of the impact of combined exposure of volcanic ash and anthropogenic pollution to human health, however, remains limited.The aim of this study was to assess the biological impact of combined exposure to respirable volcanic ash (from Soufrière Hills volcano (SHV), Montserrat and Chaitén volcano (ChV), Chile; representing different magmatic compositions and eruption styles) and freshly-generated complete exhaust from a gasoline vehicle. A multicellular human lung model (an epithelial cell-layer composed of A549 alveolar type II-like cells complemented with human blood monocyte-derived macrophages and dendritic cells cultured at the air-liquid interface) was exposed to diluted exhaust (1:10) continuously for 6 h, followed by immediate exposure to the ash as a dry powder (0.54 ± 0.19 μg/cm2 and 0.39 ± 0.09 μg/cm2 for SHV and ChV ash, respectively). After an 18 h incubation, cells were exposed again for 6 h to diluted exhaust, and a final 18 h incubation (at 37 °C and 5% CO2). Cell cultures were then assessed for cytotoxic, oxidative stress and (pro-)inflammatory responses.Results indicate that, at all tested (sub-lethal) concentrations, co-exposures with both ash samples induced no significant expression of genes associated with oxidative stress (HMOX1, NQO1) or production of (pro-)inflammatory markers (IL-1β, IL-8, TNF-α) at the gene and protein levels. In summary, considering the employed experimental conditions, combined exposure of

Impact of chronic neonicotinoid exposure on honeybee colony performance and queen supersedure.

Directory of Open Access Journals (Sweden)

Christoph Sandrock

Full Text Available BACKGROUND: Honeybees provide economically and ecologically vital pollination services to crops and wild plants. During the last decade elevated colony losses have been documented in Europe and North America. Despite growing consensus on the involvement of multiple causal factors, the underlying interactions impacting on honeybee health and colony failure are not fully resolved. Parasites and pathogens are among the main candidates, but sublethal exposure to widespread agricultural pesticides may also affect bees. METHODOLOGY/PRINCIPAL FINDINGS: To investigate effects of sublethal dietary neonicotinoid exposure on honeybee colony performance, a fully crossed experimental design was implemented using 24 colonies, including sister-queens from two different strains, and experimental in-hive pollen feeding with or without environmentally relevant concentrations of thiamethoxam and clothianidin. Honeybee colonies chronically exposed to both neonicotinoids over two brood cycles exhibited decreased performance in the short-term resulting in declining numbers of adult bees (-28% and brood (-13%, as well as a reduction in honey production (-29% and pollen collections (-19%, but colonies recovered in the medium-term and overwintered successfully. However, significantly decelerated growth of neonicotinoid-exposed colonies during the following spring was associated with queen failure, revealing previously undocumented long-term impacts of neonicotinoids: queen supersedure was observed for 60% of the neonicotinoid-exposed colonies within a one year period, but not for control colonies. Linked to this, neonicotinoid exposure was significantly associated with a reduced propensity to swarm during the next spring. Both short-term and long-term effects of neonicotinoids on colony performance were significantly influenced by the honeybees' genetic background. CONCLUSIONS/SIGNIFICANCE: Sublethal neonicotinoid exposure did not provoke increased winter losses. Yet

Exposure scenario libraries as a tool for exposure assessment

International Nuclear Information System (INIS)

Jiménez, Araceli Sánchez; Rashid, Shahzad; Van Tongeren, Martie; Brouwer, Derk; Fransman, Wouter; Fito, Carlos; Boulougouris, George

2015-01-01

The development of nanotechnology has reached a point where it is being widely applied, and numerous nanomaterials and nano-enabled products are handled across a broad range of industrial sectors. Exposure extends beyond occupational settings as products containing nanomaterials are used by different consumer groups.Despite the knowledge on their toxic effects is growing there is still not OEL for most NMS and therefore the precautionary approach is still used where levels are kept as low as possible Therefore there is a need to assess workers and consumers exposure. (paper)

Gastrointestinal uptake and fate of cadmium in rainbow trout acclimated to sublethal dietary cadmium

International Nuclear Information System (INIS)

Chowdhury, M.J.; McDonald, D.G.; Wood, C.M.

2004-01-01

Adult rainbow trout were pre-exposed to a sublethal concentration of dietary Cd (500 mg/kg dry wt.) for 30 days to induce acclimation. A gastrointestinal dose of radiolabeled Cd (276 μg/kg wet wt.) was infused into the stomach of non-acclimated and Cd-acclimated trout through a stomach catheter. Repetitive blood samples over 24 h and terminal tissue samples were taken to investigate the gastrointestinal uptake, plasma clearance kinetics, and tissue distribution of Cd. Only a small fraction of the infused dose (non-acclimated: 2.4%; Cd-acclimated: 6.6%) was internalized across the gut wall, while most was bound in the gut tissues (10-24%) or remained in the lumen (16-33%) or lost from the fish (∼50%) over 24 h. Cadmium loading during pre-exposure produced a profound increase of total Cd in the blood plasma (∼28-fold) and red blood cells (RBC; ∼20-fold). The plasma Cd-time profiles consisted of an apparent rising (uptake) phase and a declining (clearance) phase with a maximum value of uptake in 4 h, suggesting that uptake of gastrointestinally infused Cd was very rapid. Acclimation to dietary Cd did not affect plasma Cd clearance (∼0.5 ml/min), but enhanced new Cd levels in the plasma (but not in the RBC), and resulted in a longer half-life for plasma Cd. Tissue total and new Cd levels varied in different regions of the gastrointestinal tract, and overall levels in gut tissues were much greater than in non-gut tissues, reflecting the Cd exposure route. Dietary Cd, but not the infused Cd, greatly increased total Cd levels of all gut tissues in the order posterior-intestine (640-fold) > cecae (180-fold) > mid-intestine (94-fold) > stomach (53-fold) in Cd-acclimated fish relative to naieve fish. Among non-gut tissues in the Cd-acclimated fish, the great increases of total Cd levels were observed in the liver (73-fold), kidney (39-fold), carcass (35-fold), and gills (30-fold). The results provide some clear conclusions that may be useful for environmental risk

Risk of combined exposure of birds to cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant.

Science.gov (United States)

Ondracek, Karel; Bandouchova, Hana; Damkova, Veronika; Hilscherova, Klara; Kral, Jiri; Osickova, Jitka; Mlcakova, Veronika; Pohanka, Miroslav; Skochova, Hana; Vitula, Frantisek; Treml, Frantisek; Pikula, Jiri

2012-01-01

The objective of this study was to examine the hypothesis that a combination of cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant can enhance avian toxic effects produced by single exposures only. A total of 48 two-month-old Japanese quails (Coturnix coturnix japonica) with average body weight of 160 g were randomly divided into 8 experimental groups of six birds and sex ratio of 1:1. Experimental groups of control Japanese quails (C) and birds exposed to single and combined sub-lethal doses of paraoxon (P), bromadiolone (B), and microcystins in cyanobacterial biomass (M) included: C, P, P+B, B, B+M, P+M, M, and P+B+M. During the 10-day exposure birds in the respective groups received biomass containing 61.62 µg microcystins daily (i.e. 26.54 µg MC-RR, 7.62 µg MC-YR and 27.39 µg MC-LR), two 250 μg/kg doses of paraoxon, and two 500 mg/kg doses of bromadiolone. Group responses were compared using standard plasma biochemistry and antioxidant/oxidative stress parameters in tissues. While single and double combinations of toxicants induced responses in individual biochemical parameters measured and evaluated using univariate statistical analysis, those in the triple exposure were most extensive. The principal component analysis of antioxidant/oxidative stress parameters (glutathione reductase, lipid peroxidation, and ferric reducing antioxidant power) in tissues (liver, kidney, heart, brain, lungs, gonads, and pectoralis major muscle) clearly separated the triple group (P+B+M) from all single and double exposure groups and the control and indicated thus marked joint effects in the overall pattern of antioxidant/oxidative stress responses of this group. The separation was driven by the modification of the ferric reducing antioxidant power levels in heart and brain and the cardiac lipid peroxidation level, in particular. This experiment contributes to the understanding of the pathogenic mechanisms of combined sub-lethal

Effects of recombinant human granulocyte colony-stimulating factor on central and peripheral T lymphocyte reconstitution after sublethal irradiation in mice

International Nuclear Information System (INIS)

Zhao Hongxia; Guo Mei; Sun Xuedong; Ai Huisheng; Sun Wanjun; Hu Hailan; Wei Li

2013-01-01

Granulocyte colony-stimulating factor (G-CSF) is one of the most critical cytokines used for the treatment of acute radiation syndrome (ARS). In addition to the hematopoietic effects of G-CSF on the differentiation and proliferation of myeloid progenitor cells, G-CSF is also known to have immunomodulatory effects. The aim of the present study was to investigate whether G-CSF could accelerate central and peripheral T lymphocyte recovery after a sublethal dose of irradiation. Female BALB/c mice were subjected to 6 Gy of total body irradiation and then were treated with either 100 μg/kg G-CSF or an equal volume of PBS once daily for 14 days. Percentages of thymocyte subpopulations including CD4- CD8-, CD4+ CD8+, CD4+ CD8- and CD4- CD8+ T cells, peripheral CD3+, CD4+ and CD8+ cells were analyzed by flow cytometry. Recent thymic emigrants (RTEs) were assessed by real-time polymerase chain reaction (PCR) using primers specific to the 257-bp T cell receptor rearrangement excision circles (sjTRECs). The proliferative capacity of splenic mononuclear cells upon exposure to ConA was measured by using the Cell Count Kit-8 (CCK-8). G-CSF treatment promoted thymocyte regeneration, accelerated the recovery of CD4+ CD8+ cells and increased the frequency of thymocyte sjTRECs. These effects were more prominent at early time points (Day 28) after irradiation. G-CSF also increased the rate of recovery of peripheral CD3+, CD4+ and CD8+ cells and shortened the period of severe lymphopenia following irradiation. G-CSF also increased the splenic mononuclear cell mitotic responsiveness to ConA more than control-treated cells. Our results show that G-CSF accelerates T cell recovery through both thymic-dependent and thymic-independent pathways, which could be used to increase the rate of immune reconstitution after sublethal irradiation. (author)

Normal and sublethally irradiated stem and granulocyte progenitor cell regeneration in an in vivo culture system. The cellular response to humoral factors released through the action of cyclophosphamide

International Nuclear Information System (INIS)

MacVittie, T.

1977-01-01

The in vivo diffusion chamber (DC) method of marrow culture was used to determine if the injection of host mice with cyclophosphamide (CY) caused, through its cytoxic action, the release of a humoral factor(s) capable of initiating stem cell (CFU-s) and granulocyte-macrophage progenitor cell (CFU-c) proliferation. Host mice were injected with CY 1-4 days prior to 800 rad of 60 Co WBI and implantation of DCs containing normal or 400 rad sublethally irradiated (SLI) marrow cells. The greatest proliferative response within CFU-s and CFU-c populations occurred in those mice injected with CY 3 days prior to implant. The marked CFU-s and CFU-c regeneration was initiated during the initial 24 hr of culture in both normal and SLI marrow cells. Thereafter growth rates were approximately the same. SLI marrow, however, showed a greater response to the humoral effects of CY injection than did normal marrow. These data provided evidence that CY induced the release of a diffusible factor(s) capable of accelerating regeneration of normal and sublethally irradiated CFU-s and CFU-c, the magnitude of which was dependent upon the time elapsed between CY injected and implantation of DCs. The marked proliferative response of the SLI stem and progenitor cells to the humoral stimulation may be indicative of the heterogeneity of both CFU-s and CFU-c populations surviving sublethal radiation exposure. The target cells may have possessed a differential sensitivity to the factor(s) initiating cell proliferation

ASSESSING HUMAN EXPOSURE TO GRASS POLLEN IN DENMARK

DEFF Research Database (Denmark)

Peel, Robert George; Hertel, Ole; Herbert, Rob

Objectives: Exposure to pollen is typically assessed using data collected at fixed roof-top monitoring stations, which give a general picture of airborne pollen concentrations over a wide region. Actual exposure levels can be obtained through personal exposure monitoring. This is typically done u...

[Occupational exposure to nanoparticles. Assessment of workplace exposure].

Science.gov (United States)

Bujak-Pietrek, Stella

2010-01-01

Nanotechnology is currently one of the most popular branch of science. It is a technology that enables designing, manufacturing and application of materials and structures of very small dimensions, and its products are applied in almost every field of life. Nanoparticles are the structures having one or more dimensions of the order of 100 nm or less. They are used in precise mechanics, electronics, optics, medicine, pharmacy, cosmetics and many other spheres. Due to their very small size, nanostructures have completely different and specific properties, unknown for the bulk of materials. Fast-growing nanotechnology provides a wide spectrum of applications, but it also brings about new and unknown danger to human health. Nanotechnology is the branch that has developed rather recently, and much information about health risk and its influence on the environment is beyond our knowledge. Nanoparticles, released in many technological processes, as well as manufactured nanoparticles can induce occupational hazards to workers. The lack of regulations and standards, compulsory in the manufacture and use ofnanoparticles is a fundamental problem faced in the evaluation of exposure. Another problem is the choice of proper measurement equipment for surveying of very small particles - their number, mass and surface area in the workpost air. In this article, the possibility and scope of exposure assessment is discussed and a brief specification of available instrumentation for counting and assessing the parameters essential for classifying the exposure to nanoparticles is presented.

Variability and uncertainty in Swedish exposure factors for use in quantitative exposure assessments.

Science.gov (United States)

Filipsson, Monika; Öberg, Tomas; Bergbäck, Bo

2011-01-01

Information of exposure factors used in quantitative risk assessments has previously been compiled and reported for U.S. and European populations. However, due to the advancement of science and knowledge, these reports are in continuous need of updating with new data. Equally important is the change over time of many exposure factors related to both physiological characteristics and human behavior. Body weight, skin surface, time use, and dietary habits are some of the most obvious examples covered here. A wealth of data is available from literature not primarily gathered for the purpose of risk assessment. Here we review a number of key exposure factors and compare these factors between northern Europe--here represented by Sweden--and the United States. Many previous compilations of exposure factor data focus on interindividual variability and variability between sexes and age groups, while uncertainty is mainly dealt with in a qualitative way. In this article variability is assessed along with uncertainty. As estimates of central tendency and interindividual variability, mean, standard deviation, skewness, kurtosis, and multiple percentiles were calculated, while uncertainty was characterized using 95% confidence intervals for these parameters. The presented statistics are appropriate for use in deterministic analyses using point estimates for each input parameter as well as in probabilistic assessments. © 2010 Society for Risk Analysis.

Response of DNA, proteins, lipids and antioxidant enzymes as measure of toxicity to mercury exposures in green mussel Perna viridis

Digital Repository Service at National Institute of Oceanography (India)

Verlecar, X.N.; Jena, K.B.; Chainy, G.B.N.

Studies on exposures of gills of green-lipped mussel Perna viridis to sublethal levels of mercury (Hg) indicates that oxidative stress marker like lipids peroxidation and protein carbonyl content increase. With the exception of superoxide dismutase...

Health impact assessment of air pollution using a dynamic exposure profile: Implications for exposure and health impact estimates

International Nuclear Information System (INIS)

Dhondt, Stijn; Beckx, Carolien; Degraeuwe, Bart; Lefebvre, Wouter; Kochan, Bruno; Bellemans, Tom; Int Panis, Luc; Macharis, Cathy; Putman, Koen

2012-01-01

In both ambient air pollution epidemiology and health impact assessment an accurate assessment of the population exposure is crucial. Although considerable advances have been made in assessing human exposure outdoors, the assessments often do not consider the impact of individual travel behavior on such exposures. Population-based exposures to NO 2 and O 3 using only home addresses were compared with models that integrate all time-activity patterns—including time in commute—for Flanders and Brussels. The exposure estimates were used to estimate the air pollution impact on years of life lost due to respiratory mortality. Health impact of NO 2 using an exposure that integrates time-activity information was on average 1.2% higher than when assuming that people are always at their home address. For ozone the overall estimated health impact was 0.8% lower. Local differences could be much larger, with estimates that differ up to 12% from the exposure using residential addresses only. Depending on age and gender, deviations from the population average were seen. Our results showed modest differences on a regional level. At the local level, however, time-activity patterns indicated larger differences in exposure and health impact estimates, mainly for people living in more rural areas. These results suggest that for local analyses the dynamic approach can contribute to an improved assessment of the health impact of various types of pollution and to the understanding of exposure differences between population groups. - Highlights: ► Exposure to ambient air pollution was assessed integrating population mobility. ► This dynamic exposure was integrated into a health impact assessment. ► Differences between the dynamic and residential exposure were quantified. ► Modest differences in health impact were found at a regional level. ► At municipal level larger differences were found, influenced by gender and age.

Advanced REACH tool: A Bayesian model for occupational exposure assessment

NARCIS (Netherlands)

McNally, K.; Warren, N.; Fransman, W.; Entink, R.K.; Schinkel, J.; Van Tongeren, M.; Cherrie, J.W.; Kromhout, H.; Schneider, T.; Tielemans, E.

2014-01-01

This paper describes a Bayesian model for the assessment of inhalation exposures in an occupational setting; the methodology underpins a freely available web-based application for exposure assessment, the Advanced REACH Tool (ART). The ART is a higher tier exposure tool that combines disparate

Assessing the risks from exposure to radon in dwellings

International Nuclear Information System (INIS)

Walsh, P.J.; Lowder, W.M.

1983-07-01

The factors used to assess the radiation dose and health risks from human exposure to radon in dwellings are critically reviewed in this summary. Sources of indoor radon and determinants of air concentrations and exposure levels are given as well as the uncertainties that exist in their formulation. Methods of assessing health effects from inhalation of radon and its progeny are discussed with emphasis on dosimetry of radon daughters and formulation of risk per dose values. Finally, methods of assessing risks for general population exposures to indoor radon concentrations are treated

Hsp27, Hsp70, and metallothionein in MDCK and LLC-PK1 renal epithelial cells: effects of prolonged exposure to cadmium

International Nuclear Information System (INIS)

Bonham, Rita T.; Fine, Michael R.; Pollock, Fiona M.; Shelden, Eric A.

2003-01-01

Cadmium is a widely distributed industrial and environmental toxin. The principal target organ of chronic sublethal cadmium exposure is the kidney. In renal epithelial cells, acute high-dose cadmium exposure induces differential expression of proteins, including heat shock proteins. However, few studies have examined heat shock protein expression in cells after prolonged exposure to cadmium at sublethal concentrations. Here, we assayed total cell protein, neutral red uptake, cell death, and levels of metallothionein and heat shock proteins Hsp27 and inducible Hsp70 in cultures of MDCK and LLC-PK1 renal epithelial cells treated with cadmium for 3 days. Treatment with cadmium at concentrations equal to or greater than 10 μM (LLC-PK1) or 25 μM (MDCK) reduced measures of cell vitality and induced cell death. However, a concentration-dependent increase in Hsp27 was detected in both cell types treated with as little as 5 μM cadmium. Accumulation of Hsp70 was correlated only with cadmium treatment at concentrations also causing cell death. Metallothionein was maximally detected in cells treated with cadmium at concentrations that did not reduce cell vitality, and further increases were not detected at greater concentrations. These results reveal that heat shock proteins accumulate in renal epithelial cells during prolonged cadmium exposure, that cadmium induces differential expression of heat shock protein in epithelial cells, and that protein expression patterns in epithelial cells are specific to the cadmium concentration and degree of cellular injury. A potential role for Hsp27 in the cellular response to sublethal cadmium-induced injury is also implicated by our results

Exposure assessment strategies for non-routine work operations (NORWO)

International Nuclear Information System (INIS)

Lew, V.; Cohen, J.; Chiusano, S.; McGann, C.; McLouth, L.

1993-09-01

The DOE Office of Health and Office of Safety and Health Oversight are collaborating to address special problems related to assessment of worker exposures associated with nonroutine work operations (NORWO), such as hazardous waste operations. Both off ices have formed a single working group of industrial hygiene specialists from the DOE, fts contractors, and other interested organizations which held its first meeting July 1993. The DOE Canter of Excellence for Exposure Assessment, maintained at Lawrence Livermore National Laboratory, is assisting in developing reasonable policies and guidance on exposure assessment strategies for NORWO. The DOE EA Center will research this subject to assist the DOE in formulating guidance documents for conduct of EA for NORWO that are consistent with the DOE draft EAS technical standard. This report presents an outline for a section on NORWO intended for inclusion in the DOE technical guidance documents for EAS and Hazardous Waste Operations Emergency Response (HAZWOPER) currently under development by the DOE Industrial Hygiene Division (EH-412), and EM-23. Also presented is a review of the July 21--23 meeting and a proposed workplan for developing NORWO exposure assessment procedures. Appendices include: (A) David Weitzman's memo on NORWO, (B) Draft annotated outline of the technical standard for the Assessment of Employee Exposure to Hazardous Chemical Agents, (C) ORC proposed EAS standard, (D) program for the October 31--November 3, 1993 ACGIH Conference on Occupational Exposure Databases, (E) agenda for the July 15, 1993 DOE meeting on NORWO, (F) viewgraphs used in formal presentations at this meeting, (G) Hanford Exposure Assessment Program Plan, and (H) a list of attendees and invitees to the July DOE -- NORWO meeting

Exposure monitoring and risk assessment of biphenyl in the workplace.

Science.gov (United States)

Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon

2015-05-13

This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m³, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10⁻⁴ (central tendency exposure) and 0.56 × 10⁻⁴ (reasonable maximum exposure), which is below the acceptable risk value of 1.0 × 10⁻⁴. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.

Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace

Directory of Open Access Journals (Sweden)

Hyeon-Yeong Kim

2015-05-01

Full Text Available This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m3, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10−4 (central tendency exposure and 0.56 × 10−4 (reasonable maximum exposure, which is below the acceptable risk value of 1.0 × 10−4. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.

Functional modifications of macrophage activity after sublethal irradiation

International Nuclear Information System (INIS)

Swartz, R.P.

1982-01-01

The modifications of macrophage activity following sublethal irradiation, both in vivo and in vitro, were studied using spreading and C3b-receptor-mediated ingestion assays. Nonelicited peritoneal washout cells were examined for changes in activity and selected population characteristics. The cells from irradiated mice were from a resident peritoneal population and not immigrating cells. The macrophage population showed enhanced activity early with a refractory period (24-48) when the macrophages were unresponsive to stimulation by irradiated lymphocytes. The enhanced activity was inversely dose dependent on macrophage. The lymphocytes showed a regulatory function(s) on the time post irradiation at which they were examined. Early lymphocytes exhibited the ability to enhance the activity of normal macrophages while lymphocytes removed 24 hours post irradiation could suppress the activity of already activated macrophages. The effect(s) of the various lymphocyte populations were reproduced with cell-free supernatants which was indicative of the production of lymphokines. Separation on nylon wool columns indicated that the activity resided primarily in the T-cell population of lymphocytes. In vitro irradiation indicated that stimulation of the lymphocytes is macrophage dependent. Additional work indicated that sublethally irradiated macrophages did not inhibit replication of the coccidian protozoon Toxoplasma gondii although they did show increased phagocytosis. Examination of the serum from whole body irradiated mice showed the presence of a postirradiation substance which enhanced the phagocytosis of normal macrophages. It was not present in the serum of normal mice and was not endotoxin

Exposure assessment of process-related contaminants in food by biomarker monitoring.

Science.gov (United States)

Rietjens, Ivonne M C M; Dussort, P; Günther, Helmut; Hanlon, Paul; Honda, Hiroshi; Mally, Angela; O'Hagan, Sue; Scholz, Gabriele; Seidel, Albrecht; Swenberg, James; Teeguarden, Justin; Eisenbrand, Gerhard

2018-01-01

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario's and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.

Sublethal damages: their nature and repair

Energy Technology Data Exchange (ETDEWEB)

Saenko, A.S.; Synzynys, B.I.; Trofimova, S.F. (Nauchno-Issledovatel' skij Inst. Meditsinskoj Radiologii, Obninsk (USSR)); Gotlib, V.Ya.; Pelevina, I.I. (AN SSSR, Moscow. Inst. Khimicheskoj Fiziki)

1983-05-12

The molecular nature of sublethal damage (SLD) arising after ionizing irradiation of cultured mammalian cells was considered on the basis of data on DNA repair and cell recovery after SLD observed in lymphosarcoma cells as well as of literature data. The rate of SLD recovery and that of restoration of the cell's ability to initiate DNA synthesis were shown to be similar in new replicons. These data along with knowledge about the role of exchange type chromosomal aberrations in reproductive death permitted us to propose the hypothesis that conformational changes of chromatine - most probably, relaxation of condensed chromosomal material - are damage registered as SLD at the cellular level. Double-strand breaks and a slowly repaired part of DNA single-strand breaks are candidates for SLD.

A biomarker model of sublethal genotoxicity (DNA single-strand breaks and adducts) using the sentinel organism Aporrectodea longa in spiked soil

International Nuclear Information System (INIS)

Martin, Francis L.; Piearce, Trevor G.; Hewer, Alan; Phillips, David H.; Semple, Kirk T.

2005-01-01

There is a need to develop risk biomarkers during the remediation of contaminated land. We employed the earthworm, Aporrectodea longa (Ude), to determine whether genotoxicity measures could be applied to this organism's intestinal tissues. Earthworms were added, for 24 h or 7 days, to soil samples spiked with benzo[a]pyrene (B[a]P) and/or lindane. After exposure, intestinal tissues (crop/gizzard or intestine) were removed prior to the measurement in disaggregated cells of DNA single-strand breaks (SSBs) by the alkaline comet assay. Damage was quantified by comet tail length (CTL, μm). B[a]P 24-h exposure induced dose-related increases (P 32 P-postlabelling, showed a two-adduct-spot pattern. This preliminary investigation suggests that earthworm tissues may be incorporated into genotoxicity assays to facilitate hazard identification within terrestrial ecosystems. - Sublethal genotoxicity in the sentinel organism A. longa can be used to monitor the effects of contaminants in soil

Non-ionizing electromagnetic exposure assessment and dosimetry

International Nuclear Information System (INIS)

Paulsson, L.E.

1992-11-01

A comprehensive literature survey of advancements in the area 'human exposure assessment and dosimetry' for the years 1988-1992 has been performed by the author and published elsewhere. In the present report that material has been complemented with a historical background and a thorough description of the physical principles behind the methods and techniques. The report covers strategies, principles, methods, limitations and future developments for the area of human exposure assessment and dosimetry of electromagnetic fields form extremely low frequencies up to and including microwaves

Inductions of reproduction and population growth in the generalist predator Cyrtorhinus lividipennis (Hemiptera: Miridae) exposed to sub-lethal concentrations of insecticides.

Science.gov (United States)

Lu, Weiwei; Xu, Qiujing; Zhu, Jun; Liu, Chen; Ge, Linquan; Yang, Guoqing; Liu, Fang

2017-08-01

The miridbug, Cyrtorhinus lividipennis, is a significant predacious enemy of rice planthoppers. The effects of sub-lethal concentrations of triazophos, deltamethrin and imidacloprid on fecundity, egg hatchability, expression levels of genes associated with reproduction, and population growth in C. lividipennis were investigated. The fecundities for three pair combinations (♀ c × ♂ t , ♀ t × ♂ c and ♀ t × ♂ t ) treated with sub-lethal concentrations of the insecticides triazophos, deltamethrin and imidacloprid (LC 10 and LC 20 ) showed a significant increase compared to the untreated pairs (♀ c × ♂ c ). However, sub-lethal concentration treatments did not affect the egg hatchability. The ClVg expression levels of female adults exposed to triazophos, deltamethrin and imidacloprid (LC 20 ) increased by 52.6, 48.9 and 91.2%, respectively. The ClSPATA13 expression level of adult males exposed to triazophos, deltamethrim and imidacloprid (LC 20 ) increased by 80.7, 41.3 and 48.3%, respectively. Furthermore, sub-lethal concentrations of insecticides (LC 20 ) caused increased population numbers in C. lividipennis. Sub-lethal concentrations of triazophos, deltamethrin and imidacloprid stimulated reproduction and enhanced population growth of C. lividipennis. The reproductive stimulation might result from the up-regulation of ClVg or ClSPATA13. These findings may be useful in mediating populations of planthoppers. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Fipronil promotes motor and behavioral changes in honey bees (Apis mellifera) and affects the development of colonies exposed to sublethal doses.

Science.gov (United States)

Zaluski, Rodrigo; Kadri, Samir Moura; Alonso, Diego Peres; Martins Ribolla, Paulo Eduardo; de Oliveira Orsi, Ricardo

2015-05-01

Bees play a crucial role in pollination and generate honey and other hive products; therefore, their worldwide decline is cause for concern. New broad-spectrum systemic insecticides such as fipronil can harm bees and their use has been discussed as a potential threat to bees' survival. In the present study, the authors evaluate the in vitro toxicity of fipronil and note behavioral and motor activity changes in Africanized adult Apis mellifera that ingest or come into contact with lethal or sublethal doses of fipronil. The effects of sublethal doses on brood viability, population growth, behavior, and the expression of the defensin 1 gene in adult bees were studied in colonies fed with contaminated sugar syrup (8 µg fipronil L(-1) ). Fipronil is highly toxic to bees triggering agitation, seizures, tremors, and paralysis. Bees that are exposed to a lethal or sublethal doses showed reduced motor activity. The number of eggs that hatched, the area occupied by worker eggs, and the number of larvae and pupae that developed were reduced, adult bees showed lethargy, and colonies were abandoned when they were exposed to sublethal doses of fipronil. No change was seen in the bees' expression of defensin 1. The authors conclude that fipronil is highly toxic to honey bees and even sublethal doses may negatively affect the development and maintenance of colonies. © 2015 SETAC.

DREAM: a method for semi-quantitative dermal exposure assessment

NARCIS (Netherlands)

Wendel de Joode, B. van; Brouwer, D.H.; Kromhout, H.; Hemmen, J.J. van

2003-01-01

This paper describes a new method (DREAM) for structured, semi-quantitative dermal exposure assessment for chemical or biological agents that can be used in occupational hygiene or epidemiology. It is anticipated that DREAM could serve as an initial assessment of dermal exposure, amongst others,

Interactions between Entomopathogenic Fungus, Metarhizium Anisopliae and Sublethal Doses of Spinosad for Control of House Fly, Musca Domestica

Directory of Open Access Journals (Sweden)

M Sharififard

2011-06-01

Full Text Available Background: Metarhizium anisopliae strain IRAN 437C is one of the most virulent fungal isolates against house fly, Musca domestica. The objective of this study was to determine the interaction of this isolate with sublethal doses of spino­sad against housefly.Methods: In adult bioassay, conidia of entomopathogenic fungus were applied as inoculated bait at 105 and 107 spore per gram and spinosad at 0.5, 1 and 1.5 µg (A.I. per gram bait. In larval bioassay, conidia were applied as combina­tion of spore with larval bedding at 106 and 108 spore per gram and spinosad at sublethals of 0.002, 0.004 and 0.006 µg (AI per gram medium. Results: Adult mortality was 48% and 72% for fungus alone but ranged from 66–87% and 89–95% in combination treat­ments of 105 and 107 spore/g with sublethal doses of spinosad respectively. The interaction between 105 spore/g with sublethals exhibited synergistic effect, but in combination of 107 spore in spite of higher mortality, the interac­tion was additive. There was significant difference in LT50 among various treatments. LT50 values in all combination treat­ments were smaller than LT50 values in alone ones. Larval mortality was 36% and 69% for fungus alone but ranged from 58%–78% and 81%–100% in combination treatments of 106 and 108 spore/g medium with sublethals of spino­sad respectively. The interaction was synergistic in all combination treatments of larvae.Conclusion: The interaction between M. anispliae and spinosad indicated a synergetic effect that increased the house fly mortality as well as reduced the lethal time.

Accumulation and Sublethal Effects of Triclosan and its Transformation Product Methyl-triclosan in the Earthworm Eisenia andrei Exposed to Environmental Concentrations in an Artificial Soil.

Science.gov (United States)

Chevillot, Fanny; Guyot, Mélanie; Desrosiers, Mélanie; Cadoret, Nicole; Veilleux, Éloïse; Cabana, Hubert; Bellenger, Jean-Philippe

2018-04-18

Municipal biosolids are increasingly used as a low-cost fertilizer in agricultural soil. Biosolids are contaminated by low concentrations (ng g -1 dw range) of a large variety of organic contaminants, such as triclosan (TCS). The effect of exposure to low concentrations of organic contaminants on soil biota remains largely undocumented. We evaluated the sublethal effects of TCS on the earthworm Eisenia andrei using an artificial soil amended with a nominal concentration of TCS of 50 ng g -1 dry weight soil. Using a 56-d reproduction test, we monitored the effect of TCS exposure on adult earthworm survival, growth, and reproduction. The bioaccumulation of TCS in earthworm tissue (adults and juveniles) and degradation of TCS were monitored. The genotoxicity of TCS was evaluated using a comet assay (DNA damage) on adult earthworm coelomocytes. Exposure to a low concentration of TCS had no significant effects on adult earthworm survival and DNA damage, but significantly stimulated growth (P increase in the number of cocoons and juveniles, and a decrease in the mean dry weight of juveniles. The bioaccumulation of TCS in earthworms was moderate (bioaccumulation factor ∼ 2). In biosolid-borne trials, the bioaccumulation of methyl-triclosan in earthworm tissues was higher than the parent compound TCS. We conclude that exposure to low concentrations of TCS in artificial soil can significantly affect the growth and reproductive performance of earthworms (i.e., E. andrei). More research is required with natural soils to assess TCS bioavailability for earthworms. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Sublethal effects of fenpyroximate and pyridaben on two predatory mite species, Neoseiulus womersleyi and Phytoseiulus persimilis (Acari, Phytoseiidae).

Science.gov (United States)

Park, Jung-Joon; Kim, Minsik; Lee, Joon-Ho; Shin, Key-Il; Lee, Sung Eun; Kim, Jeong-Gyu; Cho, Kijong

2011-07-01

Laboratory bioassays were conducted to evaluate the sublethal effects of fenpyroximate and pyridaben on life-table parameters of two predatory mites species, Neoseiulus (= Amblyseius) womersleyi and Phytoseiulus persimilis. In these assays, young adult females were treated with three sublethal concentrations of each acaricide. The life-table parameters were calculated at each acaricide concentration, and compared using bootstrap procedures. For each acaricide, the LC(50) estimates for both species were similar, yet the two species exhibited completely different susceptibility when the population growth rate was used as the endpoint. Exposure to both acaricides reduced the net reproduction rate (R (o)) in a concentration-dependent manner and their EC(50)s were equivalent to less than LC(7). Two different scales of population-level endpoints were estimated to compare the total effect between the species and treatments: the first endpoint values were based on the net reproductive rate (fecundity λ) and the second endpoint values incorporated the mean egg hatchability into the net reproductive rate (vitality λ). The fecundity λ decreased in a concentration-dependent manner for both acaricide treatments, but the vitality λ decreased abruptly after treatment of N. womersleyi with pyridaben. The change in the patterns of λ revealed that the acaricide effects at the population level strongly depended on the life-history characteristics of the predatory mite species and the chemical mode of action. When the total effects of the two acaricides on N. womersleyi and P. persimilis were considered, fenpyroximate was found to be the most compatible acaricide for the augmentative release of N. womersleyi after treatment.

Exposure assessment of tetrafluoroethylene and ammonium perfluorooctanoate 1951-2002.

Science.gov (United States)

Sleeuwenhoek, Anne; Cherrie, John W

2012-03-01

To develop a method to reconstruct exposure to tetrafluoroethylene (TFE) and ammonium perfluorooctanoate (APFO) in plants producing polytetrafluoroethylene (PTFE) in the absence of suitable objective measurements. These data were used to inform an epidemiological study being carried out to investigate possible risks in workers employed in the manufacture of PTFE and to study trends in exposure over time. For each plant, detailed descriptions of all occupational titles, including tasks and changes over time, were obtained during semi-structured interviews with key plant personnel. A semi-quantitative assessment method was used to assess inhalation exposure to TFE and inhalation plus dermal exposure to APFO. Temporal trends in exposure to TFE and APFO were investigated. In each plant the highest exposures for both TFE and APFO occurred in the polymerisation area. Due to the introduction of control measures, increasing process automation and other improvements, exposures generally decreased over time. In the polymerisation area, the annual decline in exposure to TFE varied by plant from 3.8 to 5.7% and for APFO from 2.2 to 5.5%. A simple method for assessing exposure was developed which used detailed process information and job descriptions to estimate average annual TFE and APFO exposure on an arbitrary semi-quantitative scale. These semi-quantitative estimates are sufficient to identify relative differences in exposure for the epidemiological study and should good data become available, they could be used to provide quantitative estimates for all plants across the whole period of operation. This journal is © The Royal Society of Chemistry 2012

Health impact assessment of air pollution using a dynamic exposure profile: Implications for exposure and health impact estimates

Energy Technology Data Exchange (ETDEWEB)

Dhondt, Stijn, E-mail: stijn.dhondt@vub.ac.be [Department of Medical Sociology and Health Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels (Belgium); Beckx, Carolien, E-mail: Carolien.Beckx@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Degraeuwe, Bart, E-mail: Bart.Degraeuwe@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Lefebvre, Wouter, E-mail: Wouter.Lefebvre@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Kochan, Bruno, E-mail: Bruno.Kochan@uhasselt.be [Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Bellemans, Tom, E-mail: Tom.Bellemans@uhasselt.be [Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Int Panis, Luc, E-mail: Luc.intpanis@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Macharis, Cathy, E-mail: cjmachar@vub.ac.be [Department MOSI-Transport and Logistics, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels (Belgium); Putman, Koen, E-mail: kputman@vub.ac.be [Department of Medical Sociology and Health Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels (Belgium); Interuniversity Centre for Health Economics Research (I-CHER), Vrije Universiteit Brussel, Brussels (Belgium)

2012-09-15

In both ambient air pollution epidemiology and health impact assessment an accurate assessment of the population exposure is crucial. Although considerable advances have been made in assessing human exposure outdoors, the assessments often do not consider the impact of individual travel behavior on such exposures. Population-based exposures to NO{sub 2} and O{sub 3} using only home addresses were compared with models that integrate all time-activity patterns-including time in commute-for Flanders and Brussels. The exposure estimates were used to estimate the air pollution impact on years of life lost due to respiratory mortality. Health impact of NO{sub 2} using an exposure that integrates time-activity information was on average 1.2% higher than when assuming that people are always at their home address. For ozone the overall estimated health impact was 0.8% lower. Local differences could be much larger, with estimates that differ up to 12% from the exposure using residential addresses only. Depending on age and gender, deviations from the population average were seen. Our results showed modest differences on a regional level. At the local level, however, time-activity patterns indicated larger differences in exposure and health impact estimates, mainly for people living in more rural areas. These results suggest that for local analyses the dynamic approach can contribute to an improved assessment of the health impact of various types of pollution and to the understanding of exposure differences between population groups. - Highlights: Black-Right-Pointing-Pointer Exposure to ambient air pollution was assessed integrating population mobility. Black-Right-Pointing-Pointer This dynamic exposure was integrated into a health impact assessment. Black-Right-Pointing-Pointer Differences between the dynamic and residential exposure were quantified. Black-Right-Pointing-Pointer Modest differences in health impact were found at a regional level. Black

High hydrostatic pressure resistance of Campylobacter jejuni after different sublethal stresses.

Science.gov (United States)

Sagarzazu, N; Cebrián, G; Condón, S; Mackey, B; Mañas, P

2010-07-01

To study the development of resistance responses in Campylobacter jejuni to high hydrostatic pressure (HHP) treatments after the exposure to different stressful conditions that may be encountered in food-processing environments, such as acid pH, elevated temperatures and cold storage. Campylobacter jejuni cells in exponential and stationary growth phase were exposed to different sublethal stresses (acid, heat and cold shocks) prior to evaluate the development of resistance responses to HHP. For exponential-phase cells, neither of the conditions tested increased nor decreased HHP resistance of C. jejuni. For stationary-phase cells, acid and heat adaptation-sensitized C. jejuni cells to the subsequent pressure treatment. On the contrary, cold-adapted stationary-phase cells developed resistance to HHP. Whereas C. jejuni can be classified as a stress sensitive micro-organism, our findings have demonstrated that it can develop resistance responses under different stressing conditions. The resistance of stationary phase C. jejuni to HHP was increased after cells were exposed to cold temperatures. The results of this study contribute to a better knowledge of the physiology of C. jejuni and its survival to food preservation agents. Results here presented may help in the design of combined processes for food preservation based on HHP technology. © 2009 The Authors. Journal compilation © 2009 The Society for Applied Microbiology.

Free Radical Pathology of the Body in the Long-Term Period under Combined Exposure to Gamma Radiation and Emotional Stress in the Experiment

Science.gov (United States)

Ilderbayeva, Gulzhan O.; Suleymeneva, Dametken M.; Ilderbayev, ?ralbek Z.; Argynbekova, Ainur S.; Berekenova, Gulnar A.; Syzdykaeva, Sayrangul M.; Kabdykanov, Symbat K.

2016-01-01

We have studied the intensity of free radical and antioxidant processes in organs (liver, spleen, thymus, lymph nodes of the small intestine, and adrenal glands) and cells (lymphocytes) in the long-term period after combined exposure to a sublethal dose of ?-radiation (6 Gy) and emotional stress. Combined exposure was followed by accumulation of…

Assessment of risk of potential exposures on facilities industries

International Nuclear Information System (INIS)

Leocadio, Joao Carlos

2007-03-01

This work develops a model to evaluate potential exposures on open facilities of industrial radiography in Brazil. This model will decisively contribute to optimize operational, radiological protection and safety procedures, to prevent radiation accidents and to reduce human errors in industrial radiography. The probabilistic safety assessment (PSA) methodology was very useful to assess potential exposures. The open facilities of industrial radiography were identified as the scenario to be analyzed in what concerns the evaluation of potential exposures, due to their high accidents indices. The results of the assessment of potential exposures confirm that the industrial radiography in Brazil is a high-risk practice as classified by the IAEA. The risk of potential exposure was estimated to be 40,5 x 10 -2 per year in Brazil, having as main consequences injuries to the workers' hands and arms. In the world scene, the consequences are worst, leading to fatalities of people, thus emphasizing the high risk of industrial radiography. (author)

Integration of Probabilistic Exposure Assessment and Probabilistic Hazard Characterization

NARCIS (Netherlands)

Voet, van der H.; Slob, W.

2007-01-01

A method is proposed for integrated probabilistic risk assessment where exposure assessment and hazard characterization are both included in a probabilistic way. The aim is to specify the probability that a random individual from a defined (sub)population will have an exposure high enough to cause a

Effects of sublethal concentrations of formalin on weight gain in the ...

African Journals Online (AJOL)

The African Catfish, Clarias gariepinus, was exposed to various sublethal concentrations (25.0, 12.50, 6.25, 3.125, 1.56 and 0.0 mgl-1) of formalin to investigate their effects on the weight gain of the fish. Decrease in weight gain, directly proportional to the toxicant concentration, was observed in fish exposed to ...

Quantifying human exposure to air pollution - moving from static monitoring to spatio-temporally resolved personal exposure assessment

DEFF Research Database (Denmark)

Steinle, Susanne; Reis, Stefan; Sabel, Clive E

2013-01-01

exposure studies to accurately assess human health risks. ? We discuss potential and shortcomings of methods and tools with a focus on how their development influences study design. ? We propose a novel conceptual model for integrated health impact assessment of human exposure to air pollutants. ? We......Quantifying human exposure to air pollutants is a challenging task. Ambient concentrations of air pollutants at potentially harmful levels are ubiquitous in urban areas and subject to high spatial and temporal variability. At the same time, every individual has unique activity-patterns. Exposure...... results from multifaceted relationships and interactions between environmental and human systems, adding complexity to the assessment process. Traditionally, approaches to quantify human exposure have relied on pollutant concentrations from fixed air quality network sites and static population...

Sublethal effects of imidacloprid on targeting muscle and ribosomal protein related genes in the honey bee Apis mellifera L.

Science.gov (United States)

Wu, Yan-Yan; Luo, Qi-Hua; Hou, Chun-Sheng; Wang, Qiang; Dai, Ping-Li; Gao, Jing; Liu, Yong-Jun; Diao, Qing-Yun

2017-11-21

A sublethal concentration of imidacloprid can cause chronic toxicity in bees and can impact the behavior of honey bees. The nectar- and water-collecting, and climbing abilities of bees are crucial to the survival of the bees and the execution of responsibilities in bee colonies. Besides behavioral impact, data on the molecular mechanisms underlying the toxicity of imidacloprid, especially by the way of RNA-seq at the transcriptomic level, are limited. We treated Apis mellifera L. with sublethal concentrations of imidacloprid (0.1, 1 and 10 ppb) and determined the effect on behaviors and the transcriptomic changes. The sublethal concentrations of imidacloprid had a limited impact on the survival and syrup consumption of bees, but caused a significant increase in water consumption. Moreover, the climbing ability was significantly impaired by 10 ppb imidacloprid at 8 d. In the RNA-seq analysis, gene ontology (GO) term enrichment indicated a significant down-regulation of muscle-related genes, which might contribute to the impairment in climbing ability of bees. The enriched GO terms were attributed to the up-regulated ribosomal protein genes. Considering the ribosomal and extra-ribosomal functions of the ribosomal proteins, we hypothesized that imidacloprid also causes cell dysfunction. Our findings further enhance the understanding of imidacloprid sublethal toxicity.

Cea-Expo: A facility exposure matrix to assess passed exposure to chemical carcinogens and radionuclides of nuclear workers

International Nuclear Information System (INIS)

Telle-Lamberton, M.; Bouville, P.; Bergot, D.; Gagneau, M.; Marot, S.; Telle-Lamberton, M.; Giraud, J.M.; Gelas, J.M.

2005-01-01

A 'Facility-Exposure Matrix' (FEM) is proposed to assess exposure to chemical carcinogens and radionuclides in a cohort of nuclear workers. Exposures are to be attributed in the following way: a worker reports to an administrative unit and/or is monitored for exposure to ionising radiation in a specific workplace. These units are connected with a list of facilities for which exposure is assessed through a group of experts. The entire process of the FEM applied in one of the nuclear centres included in the study shows that the FEM is feasible: exposure durations as well as groups of correlated exposures are presented but have to be considered as possible rather than positive exposures. Considering the number of facilities to assess (330), ways to simplify the method are proposed: (i) the list of exposures will be restricted to 18 chemical products retained from an extensive bibliography study; (ii) for each of the following classes of facilities: nuclear reactors, fuel fabrication, high-activity laboratories and radiation chemistry, accelerators and irradiators, waste treatment, biology, reprocessing, fusion, occupational exposure will be deduced from the information already gathered by the initial method. Besides taking into account confusion factors in the low doses epidemiological study of nuclear workers, the matrix should help in the assessment of internal contamination and chemical exposures in the nuclear industry. (author)

Assessment of exposure dose to workers in virtual decommissioning environments

International Nuclear Information System (INIS)

Jeong, KwanSeong; Moon, JeiKwon; Choi, ByungSeon; Hyun, Dongjun; Lee, Jonghwan; Kim, Ikjune; Kim, GeunHo; Seo, JaeSeok

2014-01-01

This paper is intended to suggest the method analyze and assess the exposure dose to workers in virtual decommissioning environments. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. This work was to be able to simulate scenarios of decommissioning so that exposure dose to workers could be measured and assessed. To establish the plan of exposure dose to workers during decommissioning of nuclear facilities before decommissioning activities are accomplished, the method of simulation assessment was developed in virtual radiological environments. But this work was developed as a tool of simulation for single subject mode. Afterwards, the simulation environment for multi-subjects mode will be upgraded by simultaneous modules with networking environments. Then the much more practical method will be developed by changing number of workers and duration of time under any circumstances of decommissioning

Assessment of exposure dose to workers in virtual decommissioning environments

Energy Technology Data Exchange (ETDEWEB)

Jeong, KwanSeong; Moon, JeiKwon; Choi, ByungSeon; Hyun, Dongjun; Lee, Jonghwan; Kim, Ikjune; Kim, GeunHo; Seo, JaeSeok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-10-15

This paper is intended to suggest the method analyze and assess the exposure dose to workers in virtual decommissioning environments. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. This work was to be able to simulate scenarios of decommissioning so that exposure dose to workers could be measured and assessed. To establish the plan of exposure dose to workers during decommissioning of nuclear facilities before decommissioning activities are accomplished, the method of simulation assessment was developed in virtual radiological environments. But this work was developed as a tool of simulation for single subject mode. Afterwards, the simulation environment for multi-subjects mode will be upgraded by simultaneous modules with networking environments. Then the much more practical method will be developed by changing number of workers and duration of time under any circumstances of decommissioning.

Toxicity assessment of TiO2 nanoparticles in zebrafish embryos under different exposure conditions

International Nuclear Information System (INIS)

Clemente, Z.; Castro, V.L.S.S.; Moura, M.A.M.; Jonsson, C.M.; Fraceto, L.F.

2014-01-01

Highlights: •Nano-TiO 2 accelerated hatching of the larvae. •Exposure to anatase/rutile mixture under UV light altered the equilibrium and survival of the larvae. •Nano-TiO 2 caused alterations in the activities of CAT and GST. -- Abstract: The popularity of TiO 2 nanoparticles (nano-TiO 2 ) lies in their wide range of nanotechnological applications, together with low toxicity. Meanwhile, recent studies have shown that the photocatalytic properties of this material can result in alterations in their behavior in the environment, causing effects that have not yet been fully elucidated. The objective of this study was to evaluate the toxicity of two formulations of nano-TiO 2 under different illumination conditions, using an experimental model coherent with the principle of the three Rs of alternative animal experimentation (reduction, refinement, and replacement). Embryos of the fish Danio rerio were exposed for 96 h to different concentrations of nano-TiO 2 in the form of anatase (TA) or an anatase/rutile mixture (TM), under either visible light or a combination of visible and ultraviolet light (UV). The acute toxicity and sublethal parameters evaluated included survival rates, malformation, hatching, equilibrium, and overall length of the larvae, together with biochemical biomarkers (specific activities of catalase (CAT), glutathione S-transferase (GST), and acid phosphatase (AP)). Both TA and TM caused accelerated hatching of the larvae. Under UV irradiation, there was greater mortality of the larvae of the groups exposed to TM, compared to those exposed to TA. Exposure to TM under UV irradiation altered the equilibrium of the larvae. Alterations in the activities of CAT and GST were indicative of oxidative stress, although no clear dose-response relationship was observed. The effects of nano-TiO 2 appeared to depend on both the type of formulation and the illumination condition. The findings contribute to elucidation of the factors involved in the toxicity

Sublethal Concentrations of Antibiotics Cause Shift to Anaerobic Metabolism in Listeria monocytogenes and Induce Phenotypes Linked to Antibiotic Tolerance

DEFF Research Database (Denmark)

Knudsen, Gitte Maegaard; Fromberg, Arvid; Ng, Yin

2016-01-01

The human pathogenic bacterium Listeria monocytogenes is exposed to antibiotics both during clinical treatment and in its saprophytic lifestyle. As one of the keys to successful treatment is continued antibiotic sensitivity, the purpose of this study was to determine if exposure to sublethal...... antibiotic concentrations would affect the bacterial physiology and induce antibiotic tolerance. Transcriptomic analyses demonstrated that each of the four antibiotics tested caused an antibiotic-specific gene expression pattern related to mode-of-action of the particular antibiotic. All four antibiotics...... in Imo1179 (eutE) encoding an aldehyde oxidoreductase where rerouting caused increased ethanol production was tolerant to three of four antibiotics tested. This shift in metabolism could be a survival strategy in response to antibiotics to avoid generation of ROS production from respiration by oxidation...

Deciphering mechanisms of malathion toxicity under pulse exposure of the freshwater cladoceran Daphnia magna

DEFF Research Database (Denmark)

Trác, Ngoc Lâm; Andersen, Ole; Palmqvist, Annemette

2016-01-01

; enzyme activities of acetylcholinesterase (AChE), carboxylesterase (CbE), and glutathione S-transferase (GST); and AChE gene expression. The results showed no difference in survival among equivalent integrated doses. Adverse sublethal effects were driven by exposure concentration rather than pulse...... duration. Specifically, short pulse exposure to a high concentration of malathion resulted in more immobilized daphnids, lower AChE and CbE activities, and a higher transcript level ofAChE gene compared with long pulse exposure to low concentration. The expression of the AChE gene was up...

A linear-quadratic model of cell survival considering both sublethal and potentially lethal radiation damage

International Nuclear Information System (INIS)

Rutz, H.P.; Coucke, P.A.; Mirimanoff, R.O.

1991-01-01

The authors assessed the dose-dependence of repair of potentially lethal damage in Chinese hamster ovary cells x-irradiated in vitro. The recovery ratio (RR) by which survival (SF) of the irradiated cells was enhanced increased exponentially with a linear and a quadratic component namely ζ and ψ: RR=exp(ζD+ψD 2 ). Survival of irradiated cells can thus be expressed by a combined linear-quadratic model considering 4 variables, namely α and β for the capacity of the cells to accumulate sublethal damage, and ζ and ψ for their capacity to repair potentially lethal damage: SF=exp((ζ-α)D+ (ψ-β)D 2 ). author. 26 refs.; 1 fig.; 1 tab

Probabilistic assessment of wildfire hazard and municipal watershed exposure

Science.gov (United States)

Joe Scott; Don Helmbrecht; Matthew P. Thompson; David E. Calkin; Kate Marcille

2012-01-01

The occurrence of wildfires within municipal watersheds can result in significant impacts to water quality and ultimately human health and safety. In this paper, we illustrate the application of geospatial analysis and burn probability modeling to assess the exposure of municipal watersheds to wildfire. Our assessment of wildfire exposure consists of two primary...

The assessment of the aircrew exposure

International Nuclear Information System (INIS)

Tommasino, L.

2002-01-01

In 1991 ICRP first included exposure of aircraft crew to cosmic radiation as occupational exposure. The European Dosimetry Group (EURADOS) established a working group in 1992 to address this issue. The report 'Exposure of Air Crew to Cosmic Radiation' was published in the European Commission's Radiation Protection series as report 85. The first section of the report assesses the existing data on radiation exposure, describes the radiation environment at civil aviation altitudes and summarizes the computational models that have been developed to describe the cosmic ray radiation field in the atmosphere. The second section describes the quantities used to assess the radiation doses. It is clear that conventional radiation protection dosimetry as applied on the ground is not quite applicable to the situation for air crews. A multinational European research project was launched to investigate the problem of cosmic rays and dosimetry at aviation altitudes. The major objective was to measure the flux and energy spectra of neutrons and charged particles over a wide energy interval at aviation altitudes and compare the results with those calculated with various computer codes. Within the project much progress was made in different areas, for instance the determination of the fundamental physical characteristics of the cosmic radiation field at aircraft altitudes, development of instrumentation, measurements of dose rates and route doses and application of routine radiation protection. Surveys of air crew exposure have been carried out with different advanced dosimetric systems and comparisons were made between passive and real-time detector systems

The Future of Exposure Assessment: Perspectives from the ...

Science.gov (United States)

The British Occupational Hygiene Society, in collaboration with the Institute of Occupational Medicine, the University of Manchester, the UK Health and Safety Executive, and the University of Aberdeen hosted the 7th International Conference on the Science of Exposure Assessment (X2012) on 2 July–5 July 2012 in Edinburgh, UK. The conference ended with a special session at which invited speakers from government, industry, independent research institutes, and academia were asked to reflect on the conference and discuss what may now constitute the important highlights or drivers of future exposure assessment research. This article summarizes these discussions with respect to current and future technical and methodological developments. For the exposure science community to continue to have an impact in protecting public health, additional efforts need to be made to improve partnerships and cross-disciplinary collaborations, although it is equally important to ensure that the traditional occupational exposure themes are still covered as these issues are becoming increasingly important in the developing world. To facilitate this the ‘X’ conferences should continue to retain a holistic approach to occupational and non-occupational exposures and should actively pursue collaborations with other disciplines and professional organizations to increase the presence of consumer and environmental exposure scientists. The National Exposure Research Laboratory′s (NERL′

Making sense of nickel accumulation and sub-lethal toxic effects in saline waters: Fate and effects of nickel in the green crab, Carcinus maenas.

Science.gov (United States)

Blewett, Tamzin A; Glover, Chris N; Fehsenfeld, Sandra; Lawrence, Michael J; Niyogi, Som; Goss, Greg G; Wood, Chris M

2015-07-01

In freshwater, invertebrates nickel (Ni) is considered an ionoregulatory toxicant, but its mechanism of toxicity in marine settings, and how this varies with salinity, is poorly understood. This study investigated Ni accumulation and physiological mechanisms of sub-lethal Ni toxicity in the euryhaline green crab Carcinus maenas. Male crabs were exposed to 8.2μg/L (the US EPA chronic criterion concentration for salt waters) of waterborne Ni (radiolabelled with (63)Ni) at three different salinities, 20%, 60% and 100% SW for 24h. Whole body Ni accumulation in 20% SW was 3-5 fold greater than in 60% or 100% SW, and >80% of accumulated Ni was in the carapace at all salinities. Ni also accumulated in posterior gill 8, which showed a higher accumulation in 20% SW than in other salinities, a pattern also seen at higher exposure concentrations of Ni (500 and 3000μg/L). Gill perfusion experiments revealed that Ni was taken up by both anterior and posterior gills, but in 20% SW the posterior gill 8, which performs ionoregulatory functions, accumulated more Ni than the anterior gill 5, which primarily has a respiratory function. The sub-lethal consequences of Ni exposure were investigated by placing crabs in Ni concentrations of 8.2, 500, and 3000μg/L at 20, 60 or 100% SW for 24h. In 20% SW, haemolymph Ca levels were significantly decreased by exposure to Ni concentrations of 8.2μg/L or higher, whereas Na concentrations were depressed only at 3000μg/L. Na(+)/K(+)-ATPase activity was inhibited at both 500 and 3000μg/L in gill 8, but only in 20% SW. Haemolymph K, Mg, and osmolality were unaffected throughout, though all varied with salinity in the expected fashion. These data suggest that Ni impacts ionoregulatory function in the green crab, in a gill- and salinity-dependent manner. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantitative self-assessment of exposure to solvents among shoe repair men

NARCIS (Netherlands)

Hertsenberg, S.; Brouwer, D.; Lurvink, M.; Rubingh, C.; Rijnders, E.; Tielemans, E.

2007-01-01

Self-assessment of exposure (SAE) refers to any exposure assessment methodology wherein the worker takes an active role in establishing his or her exposure status. The objective of this study was to investigate the reliability and feasibility of SAE approaches among shoe repair workers collecting

Technical Overview of Ecological Risk Assessment - Analysis Phase: Exposure Characterization

Science.gov (United States)

Exposure Characterization is the second major component of the analysis phase of a risk assessment. For a pesticide risk assessment, the exposure characterization describes the potential or actual contact of a pesticide with a plant, animal, or media.

Spatial and Temporal Dynamics in Air Pollution Exposure Assessment

Science.gov (United States)

Dias, Daniela; Tchepel, Oxana

2018-01-01

Analyzing individual exposure in urban areas offers several challenges where both the individual’s activities and air pollution levels demonstrate a large degree of spatial and temporal dynamics. This review article discusses the concepts, key elements, current developments in assessing personal exposure to urban air pollution (seventy-two studies reviewed) and respective advantages and disadvantages. A new conceptual structure to organize personal exposure assessment methods is proposed according to two classification criteria: (i) spatial-temporal variations of individuals’ activities (point-fixed or trajectory based) and (ii) characterization of air quality (variable or uniform). This review suggests that the spatial and temporal variability of urban air pollution levels in combination with indoor exposures and individual’s time-activity patterns are key elements of personal exposure assessment. In the literature review, the majority of revised studies (44 studies) indicate that the trajectory based with variable air quality approach provides a promising framework for tackling the important question of inter- and intra-variability of individual exposure. However, future quantitative comparison between the different approaches should be performed, and the selection of the most appropriate approach for exposure quantification should take into account the purpose of the health study. This review provides a structured basis for the intercomparing of different methodologies and to make their advantages and limitations more transparent in addressing specific research objectives. PMID:29558426

Assessment of inhomogeneous ELF magnetic field exposures

International Nuclear Information System (INIS)

Leitgeb, N.; Cech, R.; Schroettner, J.

2008-01-01

In daily life as well as at workplaces, exposures to inhomogeneous magnetic fields become very frequent. This makes easily applicable compliance assessment methods increasingly important. Reference levels have been defined linking basic restrictions to levels of homogeneous fields at worst-case exposure conditions. If reference levels are met, compliance with basic restrictions can be assumed. If not, further investigations could still prove compliance. Because of the lower induction efficiency, inhomogeneous magnetic fields such as from electric appliances could be allowed exceeding reference levels. To easily assess inhomogeneous magnetic fields, a quick and flexible multi-step assessment procedure is proposed. On the basis of simulations with numerical, anatomical human models reference factors were calculated elevating reference levels to link hot-spot values measured at source surfaces to basic limits and allowing accounting for different source distance, size, orientation and position. Compliance rules are proposed minimising assessment efforts. (authors)

Standardizing measurement, sampling and reporting for public exposure assessments

Energy Technology Data Exchange (ETDEWEB)

Rochedo, Elaine R.R. [Instituto de Radioprotecao e Dosimetria, Comissao Nacional de Energia Nuclear, Av. Salvador Allende s/No. CEP 22780-160 Rio de Janeiro, RJ (Brazil)], E-mail: elaine@ird.gov.br

2008-11-15

UNSCEAR assesses worldwide public exposure from natural and man-made sources of ionizing radiation based on information submitted to UNSCEAR by United Nations Member States and from peer reviewed scientific literature. These assessments are used as a basis for radiation protection programs of international and national regulatory and research organizations. Although UNSCEAR describes its assessment methodologies, the data are based on various monitoring approaches. In order to reduce uncertainties and improve confidence in public exposure assessments, it would be necessary to harmonize the methodologies used for sampling, measuring and reporting of environmental results.

A structured observational method to assess dermal exposure to manufactured nanoparticles: DREAM as an initial assessment tool

NARCIS (Netherlands)

Duuren-Stuurman, B. van; Pelzer, J.; Moehlmann, C.; Berges, M.; Bard, D.; Wake, D.; Mark, D.; Jankowska, E.; Brouwer, D.

2010-01-01

Preliminary results of inventories of exposure scenarios for nanomaterials have indicated possible dermal exposure. Within the NANOSH project focused on occupational safety and health aspects of nanotechnology a shortened version of the observational DeRmal Exposure AssessMent (DREAM) method was

Task-based exposure assessment of nanoparticles in the workplace

International Nuclear Information System (INIS)

Ham, Seunghon; Yoon, Chungsik; Lee, Euiseung; Lee, Kiyoung; Park, Donguk; Chung, Eunkyo; Kim, Pilje; Lee, Byoungcheun

2012-01-01

Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

Biodegradation kinetics for pesticide exposure assessment.

Science.gov (United States)

Wolt, J D; Nelson, H P; Cleveland, C B; van Wesenbeeck, I J

2001-01-01

Understanding pesticide risks requires characterizing pesticide exposure within the environment in a manner that can be broadly generalized across widely varied conditions of use. The coupled processes of sorption and soil degradation are especially important for understanding the potential environmental exposure of pesticides. The data obtained from degradation studies are inherently variable and, when limited in extent, lend uncertainty to exposure characterization and risk assessment. Pesticide decline in soils reflects dynamically coupled processes of sorption and degradation that add complexity to the treatment of soil biodegradation data from a kinetic perspective. Additional complexity arises from study design limitations that may not fully account for the decline in microbial activity of test systems, or that may be inadequate for considerations of all potential dissipation routes for a given pesticide. Accordingly, kinetic treatment of data must accommodate a variety of differing approaches starting with very simple assumptions as to reaction dynamics and extending to more involved treatments if warranted by the available experimental data. Selection of the appropriate kinetic model to describe pesticide degradation should rely on statistical evaluation of the data fit to ensure that the models used are not overparameterized. Recognizing the effects of experimental conditions and methods for kinetic treatment of degradation data is critical for making appropriate comparisons among pesticide biodegradation data sets. Assessment of variability in soil half-life among soils is uncertain because for many pesticides the data on soil degradation rate are limited to one or two soils. Reasonable upper-bound estimates of soil half-life are necessary in risk assessment so that estimated environmental concentrations can be developed from exposure models. Thus, an understanding of the variable and uncertain distribution of soil half-lives in the environment is

The effects of strain and ploidy on the physiological responses of rainbow trout (Oncorhynchus mykiss) to pH 9.5 exposure.

Science.gov (United States)

Thompson, William A; Rodela, Tamara M; Richards, Jeffrey G

2015-05-01

We characterized the physiological effects of exposure to pH9.5 on one domesticated and four wild strains of diploid and triploid juvenile rainbow trout (Oncorhynchus mykiss) over two consecutive years. In the first year, 35-70% of the individuals from the wild strains showed a loss of equilibrium (LOE) at 12 h exposure to pH9.5, with all fish from wild strains experiencing a LOE by 48 h. In contrast, trout strains and ploidies. Plasma chloride decreased at 24h exposure in all trout strains and ploidies, but recovered by 72 h. No change was observed in plasma sodium. Overall, our data suggest that the domesticated strain of trout is more tolerant of pH9.5 than the wild strains, but these differences in tolerance cannot be explained by our sub-lethal assessment of ammonia balance or ion regulation. Copyright © 2015 Elsevier Inc. All rights reserved.

Addressing bystander exposure to agricultural pesticides in life cycle impact assessment

DEFF Research Database (Denmark)

Ryberg, Morten Walbech; Rosenbaum, Ralph K.; Mosqueron, Luc

2018-01-01

Residents living near agricultural fields may be exposed to pesticides drifting from the fields after application to different field crops. To address this currently missing exposure pathway in life cycle assessment (LCA), we developed a modeling framework for quantifying exposure of bystanders...... magnitude of individual bystanders can be substantially larger than the exposure of populations not living in the proximity to agricultural fields. Our framework for assessing bystander exposure to pesticide applications closes a relevant gap in the exposure assessment included in LCA for agricultural...... to pesticide spray drift from agricultural fields. Our framework consists of three parts addressing: (1) loss of pesticides from an agricultural field via spray drift; (2) environmental fate of pesticide in air outside of the treated field; and (3) exposure of bystanders to pesticides via inhalation...

An approach for assessing human exposures to chemical mixtures in the environment

International Nuclear Information System (INIS)

Rice, Glenn; MacDonell, Margaret; Hertzberg, Richard C.; Teuschler, Linda; Picel, Kurt; Butler, Jim; Chang, Young-Soo; Hartmann, Heidi

2008-01-01

Humans are exposed daily to multiple chemicals, including incidental exposures to complex chemical mixtures released into the environment and to combinations of chemicals that already co-exist in the environment because of previous releases from various sources. Exposures to chemical mixtures can occur through multiple pathways and across multiple routes. In this paper, we propose an iterative approach for assessing exposures to environmental chemical mixtures; it is similar to single-chemical approaches. Our approach encompasses two elements of the Risk Assessment Paradigm: Problem Formulation and Exposure Assessment. Multiple phases of the assessment occur in each element of the paradigm. During Problem Formulation, analysts identify and characterize the source(s) of the chemical mixture, ensure that dose-response and exposure assessment measures are concordant, and develop a preliminary evaluation of the mixture's fate. During Exposure Assessment, analysts evaluate the fate of the chemicals comprising the mixture using appropriate models and measurement data, characterize the exposure scenario, and estimate human exposure to the mixture. We also describe the utility of grouping the chemicals to be analyzed based on both physical-chemical properties and an understanding of environmental fate. In the article, we also highlight the need for understanding of changes in the mixture composition in the environment due to differential transport, differential degradation, and differential partitioning to other media. The section describes the application of the method to various chemical mixtures, highlighting issues associated with assessing exposures to chemical mixtures in the environment

Assessment of Industrial Exposure to Magnetic Fields (invited paper)

International Nuclear Information System (INIS)

Chadwick, P.

1999-01-01

Magnetic field strengths produced by industrial processes can be very large, but they often exhibit a marked spatial variation. Whilst there may be the potential for exposures of workers to be high, actual exposure will be determined to a great extent by working practices. Possible metrics for epidemiological studies might be based on the temporal variability of exposure as well as maximum operator exposure or time-weighted average exposure and, whilst it might be possible to estimate these quantities from spot magnetic field strength measurements and observed working practices, this might be very difficult to achieve in practice. An alternative would be the use of a logging dosemeter: this paper describes some of the results of exposure assessments carried out in industrial environments with a modified EMDEX II magnetic field dosemeter. Magnetic fields in industrial environments often have waveforms which are not purely sinusoidal. Distortion can be introduced by the magnetic saturation of transformer and motor cores, by rectification, by poor matching between oscillator circuits and loads and when thyristors are used to control power. The resulting repetitive but non-sinusoidal magnetic field waveforms can be recorded and analysed; the spectral data may be incorporated into possible exposure metrics. It is also important to ensure that measurement instrumentation is responding appropriately in a non-sinusoidal field and this can only be done if the spectral content of the field is characterised fully. Some non-sinusoidal magnetic field waveforms cannot be expressed as a harmonic series. Specialist instrumentation and techniques are needed to assess exposure to such fields. Examples of approaches to the assessment of exposure to repetitive and non-repetitive magnetic fields are also discussed. (author)

Instruments to assess and measure personal and environmental radiofrequency-electromagnetic field exposures.

Science.gov (United States)

Bhatt, Chhavi Raj; Redmayne, Mary; Abramson, Michael J; Benke, Geza

2016-03-01

Radiofrequency-electromagnetic field (RF-EMF) exposure of human populations is increasing due to the widespread use of mobile phones and other telecommunication and broadcasting technologies. There are ongoing concerns about potential short- and long-term public health consequences from RF-EMF exposures. To elucidate the RF-EMF exposure-effect relationships, an objective evaluation of the exposures with robust assessment tools is necessary. This review discusses and compares currently available RF-EMF exposure assessment instruments, which can be used in human epidemiological studies. Quantitative assessment instruments are either mobile phone-based (apps/software-modified and hardware-modified) or exposimeters. Each of these tool has its usefulness and limitations. Our review suggests that assessment of RF-EMF exposures can be improved by using these tools compared to the proxy measures of exposure (e.g. questionnaires and billing records). This in turn, could be used to help increase knowledge about RF-EMF exposure induced health effects in human populations.

Instruments to assess and measure personal and environmental radiofrequency-electromagnetic field exposures

International Nuclear Information System (INIS)

Bhatt, Chhavi R.; Redmayne, Mary; Abramson, Michael J.; Benke, Geza

2016-01-01

Radiofrequency-electromagnetic field (RF-EMF) exposure of human populations is increasing due to the widespread use of mobile phones and other telecommunication and broadcasting technologies. There are ongoing concerns about potential short- and long-term public health consequences from RF-EMF exposures. To elucidate the RF-EMF exposure-effect relationships, an objective evaluation of the exposures with robust assessment tools is necessary. This review discusses and compares currently available RF-EMF exposure assessment instruments, which can be used in human epidemiological studies. Quantitative assessment instruments are either mobile phone-based (apps/software-modified and hardware-modified) or exposimeters. Each of these tool has its usefulness and limitations. Our review suggests that assessment of RF-EMF exposures can be improved by using these tools compared to the proxy measures of exposure (e.g. questionnaires and billing records). This in turn, could be used to help increase knowledge about RF-EMF exposure induced health effects in human populations.

Occurrence of sublethal injury after pulsed electric fields depending on the micro-organism, the treatment medium ph and the intensity of the treatment investigated.

Science.gov (United States)

García, D; Gómez, N; Mañas, P; Condón, S; Raso, J; Pagán, R

2005-01-01

The objective was to investigate the occurrence of sublethal injury after pulsed electric field (PEF) depending on the treatment time, the electric field strength and the pH of the treatment media in two Gram-positive (Bacillus subtilis ssp. niger, Listeria monocytogenes) and six Gram-negative (Escherichia coli, Escherichia coli O157:H7, Pseudomonas aeruginosa, Salmonella serotype Senftenberg 775W, Salmonella serotype Typhimurium, Yersinia enterocolitica) bacterial strains. A characteristic behaviour was observed for the Gram-positive and Gram-negative bacteria studied. Whereas Gram-positive bacteria showed a higher PEF resistance at pH 7.0, the Gram-negative were more resistant at pH 4.0. In these conditions, in which bacteria showed their maximum resistance, a large proportion of sublethally injured cells were detected. In most cases, the longer the treatment time and the higher the electric field applied, the greater the proportion of sublethally injured cells that were detected. No sublethal injury was detected when Gram-positive bacteria were treated at pH 4.0 and Gram-negative at pH 7.0. Sublethal injury was detected after PEF so, bacterial inactivation by PEF is not an 'all or nothing' event. This work could be useful for improving food preservation by PEF.

Existing Default Values and Recommendations for Exposure Assessment - A Nordic Exposure Group Project 2011

DEFF Research Database (Denmark)

Höglund, Lena; Räisänen, Jouni; Hämäläinen, Anne-Maija

range of more or less well-documented values originating from many different sources. The purpose of this report is to give an overview and to evaluate exposure factors that are currently used by the authorities and industry in the exposure assessments for both adults (occupational and consumer exposure......) and children in relation to REACH. Another important purpose of the report is to contribute towards a further harmonisation of exposure factors by giving recommendations of most valid and representative defaults. These recommendations can be used besides REACH also in biocide's and plant protection product...

Retrospective internal radiation exposure assessment in occupational epidemiology

International Nuclear Information System (INIS)

Neton, J.W.; Flora, J.T.; Spitz, H.B.; Taulbee, T.D.

2000-01-01

Epidemiologic studies of workers at U.S. Department of Energy facilities are being conducted by the U.S. National Institute for Occupational Safety and Health to evaluate the health risk associated with exposure to sources of external and internal ionizing radiation. While exposure to external sources of radiation can be estimated from personal dosimeter data, reconstruction of exposure due to internally deposited radioactivity is more challenging because bioassay monitoring data is frequently less complete. Although comprehensive monitoring was provided for workers with the highest internal exposures, the majority of workers were monitored relatively infrequently. This monitoring was conducted to demonstrate compliance with regulations rather than to evaluate exposure for use in epidemiologic studies. Attributes of past internal monitoring programs that challenge accurate exposure assessment include: incomplete characterization of the workplace source term; a lack of timely measurements; insensitive and/or nonspecific bioassay measurements; and the presence of censored data. In spite of these limitations, many facilities have collected a large amount of worker and workplace monitoring information that can be used to evaluate internal exposure while minimizing worker misclassification. This paper describes a systematic approach for using the available worker and workplace monitoring data that can lead to either a qualitative or quantitative retrospective assessment of internal exposures. Various aspects of data analysis will be presented, including the evaluation of minimum detectable dose, the treatment of censored data, and the use of combinations of bioassay and workplace data to characterize exposures. Examples of these techniques applied to a cohort study involving chronic exposure scenarios to uranium are provided. A strategy for expressing exposure or dose in fundamental, unweighted units related to the quantity of radiation delivered to an organ will also

Human exposure assessment: Approaches for chemicals (REACH) and biocides (BPD)

NARCIS (Netherlands)

Hemmen, J.J. van; Gerritsen-Ebben, R.

2008-01-01

The approaches that are indicated in the various guidance documents for the assessment of human exposure for chemicals and biocides are summarised. This reflects the TNsG (Technical notes for Guidance) version 2: human exposure assessment for biocidal products (1) under the BPD (Biocidal Products

Toxicity assessment of TiO{sub 2} nanoparticles in zebrafish embryos under different exposure conditions

Energy Technology Data Exchange (ETDEWEB)

Clemente, Z., E-mail: zairaclemente@yahoo.com.br [Laboratório de Ecotoxicologia e Biossegurança, Embrapa CNPMA, Jaguariúna, SP (Brazil); Programa de Pós-graduação em Biologia Funcional e Molecular, UNICAMP, Campinas, SP (Brazil); Castro, V.L.S.S. [Laboratório de Ecotoxicologia e Biossegurança, Embrapa CNPMA, Jaguariúna, SP (Brazil); Moura, M.A.M. [Laboratório da Ciência das Plantas Daninhas, Instituto Biológico, APTA/SAA, Campinas, SP (Brazil); Jonsson, C.M. [Laboratório de Ecotoxicologia e Biossegurança, Embrapa CNPMA, Jaguariúna, SP (Brazil); Fraceto, L.F. [Programa de Pós-graduação em Biologia Funcional e Molecular, UNICAMP, Campinas, SP (Brazil); Departamento de Engenharia Ambiental, UNESP, Sorocaba, SP (Brazil)

2014-02-15

Highlights: •Nano-TiO{sub 2} accelerated hatching of the larvae. •Exposure to anatase/rutile mixture under UV light altered the equilibrium and survival of the larvae. •Nano-TiO{sub 2} caused alterations in the activities of CAT and GST. -- Abstract: The popularity of TiO{sub 2} nanoparticles (nano-TiO{sub 2}) lies in their wide range of nanotechnological applications, together with low toxicity. Meanwhile, recent studies have shown that the photocatalytic properties of this material can result in alterations in their behavior in the environment, causing effects that have not yet been fully elucidated. The objective of this study was to evaluate the toxicity of two formulations of nano-TiO{sub 2} under different illumination conditions, using an experimental model coherent with the principle of the three Rs of alternative animal experimentation (reduction, refinement, and replacement). Embryos of the fish Danio rerio were exposed for 96 h to different concentrations of nano-TiO{sub 2} in the form of anatase (TA) or an anatase/rutile mixture (TM), under either visible light or a combination of visible and ultraviolet light (UV). The acute toxicity and sublethal parameters evaluated included survival rates, malformation, hatching, equilibrium, and overall length of the larvae, together with biochemical biomarkers (specific activities of catalase (CAT), glutathione S-transferase (GST), and acid phosphatase (AP)). Both TA and TM caused accelerated hatching of the larvae. Under UV irradiation, there was greater mortality of the larvae of the groups exposed to TM, compared to those exposed to TA. Exposure to TM under UV irradiation altered the equilibrium of the larvae. Alterations in the activities of CAT and GST were indicative of oxidative stress, although no clear dose-response relationship was observed. The effects of nano-TiO{sub 2} appeared to depend on both the type of formulation and the illumination condition. The findings contribute to elucidation of the

Study of Engraftment of human cord blood cells to rescue the sublethal radiation damage mice

International Nuclear Information System (INIS)

Cao Xiangshan; Zou Zhenghui; Yu Fei; Zhang Zhilin; Lin Baojue

1997-01-01

To investigate alternative source of hematopoiesis stem cells to rescue the sublethal radiation damage (SRD) casualties. Human-umbilical cord blood hematopoietic cells were transplanted into SRD mice, the survival rate and the hematopoiesis reconstitution of bone marrow were assessed. The survival rate, in the mice transplanted and the untransplanted, were 90% and 10% respectively. Bone marrow and spleen of survival mice showed human leukocytic antigen CD45 + cells. Presence of multilineage engraftment, including myeloid and erythroid lineages, were found indicating that immature human cells home to the mouse bone marrow. conclusion: engraftment of umbilical cord blood cells is very useful to reconstitute hematopoiesis of SRD casualties. As cord blood has many advantages over bone marrow and peripheral blood, it is important in rescuing radiation accidental casualties

Assessment of occupational exposure to radiofrequency fields and radiation

International Nuclear Information System (INIS)

Cooper, T. G.; Allen, S. G.; Blackwell, R. P.; Litchfield, I.; Mann, S. M.; Pope, J. M.; Van Tongeren, M. J. A.

2004-01-01

The use of personal monitors for the assessment of exposure to radiofrequency fields and radiation in potential future epidemiological studies of occupationally exposed populations has been investigated. Data loggers have been developed for use with a commercially available personal monitor and these allowed personal exposure records consisting of time-tagged measurements of electric and magnetic field strength to be accrued over extended periods of the working day. The instrumentation was worn by workers carrying out tasks representative of some of their typical daily activities at a variety of radio sites. The results indicated significant differences in the exposures of workers in various RF environments. A number of measures of exposure have been examined with a view to assessing possible exposure metrics for epidemiological studies. There was generally a good correlation between a given measure of electric field strength and the same measure of magnetic field strength. (authors)

Categorization framework to aid exposure assessment of nanomaterials in consumer products

DEFF Research Database (Denmark)

Hansen, Steffen Foss; Michelson, Evan S.; Kamper, Anja

2008-01-01

Exposure assessment is crucial for risk assessment for nanomaterials. We propose a framework to aid exposure assessment in consumer products. We determined the location of the nanomaterials and the chemical identify of the 580 products listed in the inventory maintained by the Woodrow Wilson Inte...

Sublethal effects of catch-and-release fishing: measuring capture stress, fish impairment, and predation risk using a condition index

Science.gov (United States)

Campbell, Matthew D.; Patino, Reynaldo; Tolan, J.M.; Strauss, R.E.; Diamond, S.

2009-01-01

The sublethal effects of simulated capture of red snapper (Lutjanus campechanus) were analysed using physiological responses, condition indexing, and performance variables. Simulated catch-and-release fishing included combinations of depth of capture and thermocline exposure reflective of environmental conditions experienced in the Gulf of Mexico. Frequency of occurrence of barotrauma and lack of reflex response exhibited considerable individual variation. When combined into a single condition or impairment index, individual variation was reduced, and impairment showed significant increases as depth increased and with the addition of thermocline exposure. Performance variables, such as burst swimming speed (BSS) and simulated predator approach distance (AD), were also significantly different by depth. BSSs and predator ADs decreased with increasing depth, were lowest immediately after release, and were affected for up to 15 min, with longer recovery times required as depth increased. The impairment score developed was positively correlated with cortisol concentration and negatively correlated with both BSS and simulated predator AD. The impairment index proved to be an efficient method to estimate the overall impairment of red snapper in the laboratory simulations of capture and shows promise for use in field conditions, to estimate release mortality and vulnerability to predation.

Histological assessment of gills and liver of Oncorhynchus mykiss exposed to sublethal concentrations of the antibiotic erythromycin

Directory of Open Access Journals (Sweden)

Sara Rodrigues

2015-12-01

Full Text Available The ever-increasing presence of therapeutic drugs in the aquatic environment has been systematically reported during the past years. Among these substances, antibiotics are particularly important because they are widely used in medical and veterinary practice, livestock production and aquaculture. Erythromycin (ERY is a macrolide antibiotic, which is widely used in human therapeutics, but also in aquaculture practices. ERY was already detected in surface waters, in levels between several 19.2 ng/L to 1 μg/L. Therefore, it is necessary to characterize its potential ecotoxicological effects, including tissue modifications in target and non-target species. Histological assessment of different tissues of exposed fish are useful tools for ecotoxicological studies, helping to establish causal relationships between contaminant exposure and several biological responses. This study assessed the acute and chronic histopathological effects of erythromycin in Oncorhynchus mykiss. Gills and liver of rainbow trout were examined histologically after acute (0.001, 0.010, 0.100, 1.000 and 10.00 mg/L and chronic (0.05, 0.10, 0.20, 0.40 and 0.80 µg/L exposures. A qualitative and semi-qualitative evaluation of both tissues was performed, and also a quantitative evaluation of various lamellar structures (morphometric measurements and PAGE index (proportion of the secondary lamellae available for gas exchange. In both exposures, proliferative and degenerative alterations were the most predominant changes in gills. Organisms exposed to the highest concentrations of erythromycin had significant higher gill pathological indices in both acute and chronic experiments. Significant alterations in morphometric measurements and a decrease in the PAGE index were also observed. O. mykiss exposed to ERY had slightly higher levels of degenerative and circulatory alterations in liver. The liver pathological index increased significantly with higher concentrations for both

Occupational exposure assessment: Practices in Malaysian nuclear agency

Energy Technology Data Exchange (ETDEWEB)

Sarowi, S. Muhd, E-mail: suzie@nuclearmalaysia.gov.my; Ramli, S. A.; Kontol, K. Mohamad [Radiation Safety & Health Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia); Rahman, N. A. H. Abd. [Faculty of Science & Mathematics, Sultan Idris of Education Universit, 35900, Tanjong Malim, Perak Darul Ridzuan (Malaysia)

2016-01-22

Malaysian Nuclear Agency (Nuclear Malaysia) is the leading agency in introducing and promoting the application of nuclear science technology in Malaysia. The agency provides major nuclear facilities purposely for research and commercialisation such as reactor, irradiation plants and radioisotope production laboratory. When dealing with ionizing radiation, there is an obligatory requirement to monitor and assess the radiation exposure to the workers. The personal dose of radiation workers were monitored monthly by assessing their Thermoluminescence Dosimeter (TLD) dose reading. This paper will discuss the current practice in managing, assessing, record keeping and reporting of the occupational exposure in Nuclear Malaysia including the Health Physic Group roles and challenges. The statistics on occupational radiation exposure of monitored workers working in different fields in Nuclear Malaysia from 2011 - 2013 will also be presented. The results show that the null hypothesis (H{sub 0}) was accepted which the means of every populations are all equal or not differ significantly. This hypothesis states that the dose exposure received by the radiation workers in Nuclear Malaysia is similar and there were no significant changes from 2011 to 2013. The radiation monitoring programme correlate with the requirement of our national law, the Atomic Energy Licensing Act 1984 (Act 304)

Occupational exposure assessment: Practices in Malaysian nuclear agency

Science.gov (United States)

Sarowi, S. Muhd; Ramli, S. A.; Kontol, K. Mohamad; Rahman, N. A. H. Abd.

2016-01-01

Malaysian Nuclear Agency (Nuclear Malaysia) is the leading agency in introducing and promoting the application of nuclear science technology in Malaysia. The agency provides major nuclear facilities purposely for research and commercialisation such as reactor, irradiation plants and radioisotope production laboratory. When dealing with ionizing radiation, there is an obligatory requirement to monitor and assess the radiation exposure to the workers. The personal dose of radiation workers were monitored monthly by assessing their Thermoluminescence Dosimeter (TLD) dose reading. This paper will discuss the current practice in managing, assessing, record keeping and reporting of the occupational exposure in Nuclear Malaysia including the Health Physic Group roles and challenges. The statistics on occupational radiation exposure of monitored workers working in different fields in Nuclear Malaysia from 2011 - 2013 will also be presented. The results show that the null hypothesis (H₀) was accepted which the means of every populations are all equal or not differ significantly. This hypothesis states that the dose exposure received by the radiation workers in Nuclear Malaysia is similar and there were no significant changes from 2011 to 2013. The radiation monitoring programme correlate with the requirement of our national law, the Atomic Energy Licensing Act 1984 (Act 304).

Occupational exposure assessment: Practices in Malaysian nuclear agency

International Nuclear Information System (INIS)

Sarowi, S. Muhd; Ramli, S. A.; Kontol, K. Mohamad; Rahman, N. A. H. Abd.

2016-01-01

Malaysian Nuclear Agency (Nuclear Malaysia) is the leading agency in introducing and promoting the application of nuclear science technology in Malaysia. The agency provides major nuclear facilities purposely for research and commercialisation such as reactor, irradiation plants and radioisotope production laboratory. When dealing with ionizing radiation, there is an obligatory requirement to monitor and assess the radiation exposure to the workers. The personal dose of radiation workers were monitored monthly by assessing their Thermoluminescence Dosimeter (TLD) dose reading. This paper will discuss the current practice in managing, assessing, record keeping and reporting of the occupational exposure in Nuclear Malaysia including the Health Physic Group roles and challenges. The statistics on occupational radiation exposure of monitored workers working in different fields in Nuclear Malaysia from 2011 - 2013 will also be presented. The results show that the null hypothesis (H 0 ) was accepted which the means of every populations are all equal or not differ significantly. This hypothesis states that the dose exposure received by the radiation workers in Nuclear Malaysia is similar and there were no significant changes from 2011 to 2013. The radiation monitoring programme correlate with the requirement of our national law, the Atomic Energy Licensing Act 1984 (Act 304)

Uncovering the exposure mechanisms of sunken heavy oil that makes it chronically toxic to early life stages of fish

International Nuclear Information System (INIS)

Martin, J.; Young, G.; Lemire, B.; Hodson, P.

2010-01-01

A train derailment in 2005 caused the release of 150,000 litres of No. 6 heavy fuel oil into a lake in Alberta. The oil is a residue of the crude oil refinement process and contains 3-4 ringed alkylated forms of polycyclic aromatic hydrocarbons (PAH) that are known to cause sub-lethal toxic responses during the early life stages of rainbow trout. Because the oil does not disperse well, oil patches still persist in near-shore sediments of the lake where fish spawn. This study assessed how the behaviour of heavy oil in water interacts with exposure and toxicity to the early life stages of fish. Daily renewal tests with heavy fuel oil coated on glass plate demonstrated higher levels of toxicity to trout embryos than oil that was mechanically or chemically dispersed. A flow-through oil gravel column was used to assess whether the toxic constituents of the heavy oil are transferred quickly enough to cause toxicity. The aim of the study was to develop exposure and toxicity test methods that accurately reflect the behaviour of heavy oil after a spill.

Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace

OpenAIRE

Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon

2015-01-01

This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable ma...

INFLUENCE OF EXPOSURE ASSESSMENT METHOD IN AN EPIDEMIOLOGIC STUDY OF TRIHALOMETHANE EXPOSURE AND SPONTANEOUS ABORTION

Science.gov (United States)

Trihalomethanes are common contaminants of chlorinated drinking water. Studies of their health effects have been hampered by exposure misclassification, due in part to limitations inherent in using utility sampling records. We used two exposure assessment methods, one based on ut...

Radiobiologic effect of intermittent radiation exposure in murine tumors

International Nuclear Information System (INIS)

Sugie, Chikao; Shibamoto, Yuta; Ito, Masato; Ogino, Hiroyuki; Miyamoto, Akihiko; Fukaya, Nobuyuki; Niimi, Hiroshige; Hashizume, Takuya

2006-01-01

Purpose: In stereotactic irradiation using a linear accelerator, the effect of radiation may be reduced during intermittent exposures owing to recovery from sublethal damage in tumor cells. After our previous in vitro study suggesting this phenomenon, we investigated the issue in murine tumors. Methods and Materials: We used EMT6 and SCCVII tumors approximately 1 cm in diameter growing in the hind legs of syngeneic mice. Three schedules of intermittent radiation were investigated. First, 2 fractions of 10 Gy were given at an interval of 15-360 min to investigate the pattern of recovery from sublethal damage. Second, 5 fractions of 4 Gy were given with interfraction intervals of 2.5-15 min each. Third, 10 fractions of 2 Gy were given with interfraction intervals of 1-7 min each. Doses of 15-20 Gy were also given without interruption to estimate the dose-modifying factors. Tumors were excised 20 h later, and tumor cell survival was determined by an in vivo-in vitro assay. Results: In the 2-fraction experiment, the increase in cell survival with elongation of the interval was much less than that observed in our previous in vitro study. In the 5- and 10-fraction experiments, no significant increase in cell survival was observed after the intermittent exposures. Moreover, cell survival decreased at most points of the 5-fraction experiments by interruption of radiation in both EMT6 and SCCVII tumors. In the 10-fraction experiment, cell survival also decreased when the interruption was 3 or 7 min in EMT6 tumors. Conclusion: The results of the present in vivo studies were different from those of our in vitro studies in which cell survival increased significantly when a few minutes or longer intervals were posed between fractions. This suggests that recovery from sublethal damage in vivo may be counterbalanced by other phenomena such as reoxygenation that sensitizes tumor cells to subsequent irradiation

Effects of Sublethal Concentrations of Cyantraniliprole on the Development, Fecundity and Nutritional Physiology of the Black Cutworm Agrotis ipsilon (Lepidoptera: Noctuidae.

Directory of Open Access Journals (Sweden)

Chunmei Xu

Full Text Available To better understand the sublethal effects of cyantraniliprole on the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae, several studies were carried out to investigate sublethal effects on development stages, population parameters, feeding indices and nutrient content of A. ipsilon. The result of a bioassay showed that cyantraniliprole had high toxicity against A. ipsilon fourth-instar larvae with an LC50 of 0.354 μg.g-1 using an artificial diet. Compared with controls, sublethal doses of cyantraniliprole at LC5, LC20 and LC40 levels prolonged larval and pupal duration and extended mean generation time and total preovipositional period. In addition, survival rate, reproductive value, intrinsic and finite rates of increase and net reproduction rate declined significantly. Meanwhile, cyantraniliprole had markedly antifeedant effects; decreased the relative growth rate (RGR, the relative consumption rate (RCR, the efficiency of conversion of ingested food (ECI, the efficiency of conversion of digested food (ECD; and increased the approximate digestibility (AD significantly. This phenomenon contributed to the decrease of nutrient contents, including lipids, protein and carbohydrates, to the point that insufficient energy was available for normal growth. Therefore, sublethal concentrations of cyantraniliprole decreased growth speed and reduced population reproduction of A. ipsilon. This result provides information useful in integrated pest management (IPM programs for A. ipsilon.

Assessment of personal exposures to optical radiation in large entertainment venues

International Nuclear Information System (INIS)

Bonner, R.; O'Hagan, J. B.; Khazova, M.

2012-01-01

Workplace exposure to optical radiation from artificial sources is regulated in Europe under the Artificial Optical Radiation Directive 2006/25/EC implemented in the UK as The Control of Artificial Optical Radiation at Work Regulations 2010. The entertainment environment often presents an extremely complex situation for the assessment of occupational exposures. Multiple illumination sources, continuously changing illumination conditions and people moving during performances add further complexity to the assessment. This document proposes a methodology for assessing the risks arising from exposure to optical radiation and presents detailed case studies of practical assessment for two large entertainment venues. (authors)

Quantifying human exposure to air pollution--moving from static monitoring to spatio-temporally resolved personal exposure assessment.

Science.gov (United States)

Steinle, Susanne; Reis, Stefan; Sabel, Clive Eric

2013-01-15

Quantifying human exposure to air pollutants is a challenging task. Ambient concentrations of air pollutants at potentially harmful levels are ubiquitous in urban areas and subject to high spatial and temporal variability. At the same time, every individual has unique activity-patterns. Exposure results from multifaceted relationships and interactions between environmental and human systems, adding complexity to the assessment process. Traditionally, approaches to quantify human exposure have relied on pollutant concentrations from fixed air quality network sites and static population distributions. New developments in sensor technology now enable us to monitor personal exposure to air pollutants directly while people are moving through their activity spaces and varying concentration fields. The literature review on which this paper is based on reflects recent developments in the assessment of human exposure to air pollution. This includes the discussion of methodologies and concepts, and the elaboration of approaches and study designs applied in the field. We identify shortcomings of current approaches and discuss future research needs. We close by proposing a novel conceptual model for the integrated assessment of human exposure to air pollutants taking into account latest technological capabilities and contextual information. Copyright © 2012 Elsevier B.V. All rights reserved.

In Vitro Exposure Systems and Dosimetry Assessment Tools ...

Science.gov (United States)

In 2009, the passing of The Family Smoking Prevention and Tobacco Control Act facilitated the establishment of the FDA Center for Tobacco Products (CTP) and gave it regulatory authority over the marketing, manufacture and distribution of tobacco products, including those termed “modified risk”. On 4-6 April 2016, the Institute for In Vitro Sciences, Inc. (IIVS) convened a workshop conference titled “In Vitro Exposure Systems and Dosimetry Assessment Tools for Inhaled Tobacco Products” to bring together stakeholders representing regulatory agencies, academia, and industry to address the research priorities articulated by the FDA CTP. Specific topics were covered to assess the status of current in vitro smoke and aerosol/vapor exposure systems, as well as the various approaches and challenges to quantifying the complex exposures, in in vitro pulmonary models developed for evaluating adverse pulmonary events resulting from tobacco product exposures. The four core topics covered were, 1) Tobacco Smoke And E-Cigarette Aerosols, 2) Air-Liquid Interface-In Vitro Exposure Systems, 3) Dosimetry Approaches For Particles And Vapors; In Vitro Dosimetry Determinations and 4) Exposure Microenvironment/Physiology Of Cells. The two and a half day workshop included presentations from 20 expert speakers, poster sessions, networking discussions, and breakout sessions which identified key findings and provided recommendations to advance these technologies. Here, we will re

Sublethal doses of neonicotinoid imidacloprid can interact with honey bee chemosensory protein 1 (CSP1) and inhibit its function

International Nuclear Information System (INIS)

Li, Hongliang; Tan, Jing; Song, Xinmi; Wu, Fan; Tang, Mingzhu; Hua, Qiyun; Zheng, Huoqing; Hu, Fuliang

2017-01-01

As a frequently used neonicotinoid insecticide, imidacloprid can impair the chemoreceptive behavior of honey bees even at sublethal doses, while the physiochemical mechanism has not been further revealed. Here, multiple fluorescence spectra, thermodynamic method, and molecular docking were used to study the interaction and the functional inhibition of imidacloprid to the recombinant CSP1 protein in Asian honey bee, Apis cerana. The results showed that the fluorescence intensity (λ em  = 332 nm) of CSP1 could be significantly quenched by imidacloprid in a dynamic mode. During the quenching process, ΔH > 0, ΔS > 0, indicating that the acting forces of imidacloprid with CSP1 are mainly hydrophobic interactions. Synchronous fluorescence showed that the fluorescence of CSP1 was mainly derived from tryptophan, and the hydrophobicity of tryptophan decreased with the increase of imidacloprid concentration. Molecular docking predicted the optimal pose and the amino acid composition of the binding process. Circular dichroism (CD) spectra showed that imidacloprid reduced the α-helix of CSP1 and caused the extension of the CSP1 peptide chain. In addition, the binding of CSP1 to floral scent β-ionone was inhibited by nearly 50% of the apparent association constant (K A ) in the presence of 0.28–2.53 ng/bee of imidacloprid, and the inhibition rate of nearly 95% at 3.75 ng/bee of imidacloprid at sublethal dose level. This study initially revealed the molecular physiochemical mechanism that sublethal doses of neonicotinoid still interact and inhibit the physiological function of the honey bees' chemoreceptive system. - Highlights: • Sublethal doses of imidacloprid can directly interact with CSP1 in Apis cerana. • Sublethal imidacloprid can inhibit the function of CSP1 binding to semiochemicals. • The fluorescence intensity of CSP1 quenched by imidacloprid in a dynamic mode. • The binding between CSP1 and imidacloprid are driven by hydrophobic interactions. �

Induction and recovery of morphofunctional changes in the intestine of juvenile carnivorous fish (Epinephelus coioides) upon exposure to foodborne benzo[a]pyrene

Energy Technology Data Exchange (ETDEWEB)

Yuen, Bonny B.H. [Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Nicholas School of the Environment, Duke University, Durham, NC (United States); Wong, Chris K.C. [Department of Biology, Baptist University of Hong Kong, Waterloo Road, Kowloon, Hong Kong (China); Woo, N.Y.S. [Department of Biology, Chinese University of Hong Kong, New Territory, Hong Kong (China); Au, Doris W.T. [Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: bhdwtau@cityu.edu.hk

2007-05-15

The sublethal toxicity of dietary benzo[a]pyrene, B[a]P, on fish growth and intestinal morphofunctional changes [as measured by epithelial turnover, cell proliferation, hyperplasia, de novo crypt formation and protein absorption efficiency (i.e. expression of proton/peptide co-transporter, PepT-1, on the mucosal brush border)] were studied for the carnivorous orange-spotted grouper (Epinephelus coioides). Juvenile fish were force-fed daily with pellets containing environmentally realistic concentrations of B[a]P (dissolved in corn oil) at 0.25 {mu}g/g body weight (low-dose) and 12.5 {mu}g/g body weight (high-dose) for 4 weeks, followed by a control diet for a further 4 weeks to assess recovery. Although growth inhibition was observed in fish treated with high-dose B[a]P during the exposure period, no mortality was observed throughout the 8-week experiment. Significant hyperplasia of basal enterocytes of mucosal folds was detected shortly after 3-day exposure to the high-dose B[a]P. Moreover, a faster epithelial turnover was measured in the high-dose B[a]P exposed fish at exposure week 1, which was followed by an increase of basal cell proliferation and a reduction of PepT-1 expression at exposure week 2. The formation of de novo crypts, resemblance to the cancer predisposition syndrome 'juvenile polyposis', was significantly higher in the intestine of high-dose treated fish as compared to the control at exposure week 2 and onwards. Abnormal cytoplasmic extrusions were frequently observed in mucosal folds of high-dose fish at exposure week 4. In the low-dose treatment group, only the expression of PepT-1 was significantly reduced at exposure week 2 and an early adaptive response was observed at exposure week 4. Despite all these intestinal disturbances were reversible in fish upon the abatement to dietary B[a]P (within 1-4 weeks), environmental realistic levels of foodborne B[a]P could induce sublethal toxicity to E. coioides, and probably impose potential

Induction and recovery of morphofunctional changes in the intestine of juvenile carnivorous fish (Epinephelus coioides) upon exposure to foodborne benzo[a]pyrene

International Nuclear Information System (INIS)

Yuen, Bonny B.H.; Wong, Chris K.C.; Woo, N.Y.S.; Au, Doris W.T.

2007-01-01

The sublethal toxicity of dietary benzo[a]pyrene, B[a]P, on fish growth and intestinal morphofunctional changes [as measured by epithelial turnover, cell proliferation, hyperplasia, de novo crypt formation and protein absorption efficiency (i.e. expression of proton/peptide co-transporter, PepT-1, on the mucosal brush border)] were studied for the carnivorous orange-spotted grouper (Epinephelus coioides). Juvenile fish were force-fed daily with pellets containing environmentally realistic concentrations of B[a]P (dissolved in corn oil) at 0.25 μg/g body weight (low-dose) and 12.5 μg/g body weight (high-dose) for 4 weeks, followed by a control diet for a further 4 weeks to assess recovery. Although growth inhibition was observed in fish treated with high-dose B[a]P during the exposure period, no mortality was observed throughout the 8-week experiment. Significant hyperplasia of basal enterocytes of mucosal folds was detected shortly after 3-day exposure to the high-dose B[a]P. Moreover, a faster epithelial turnover was measured in the high-dose B[a]P exposed fish at exposure week 1, which was followed by an increase of basal cell proliferation and a reduction of PepT-1 expression at exposure week 2. The formation of de novo crypts, resemblance to the cancer predisposition syndrome 'juvenile polyposis', was significantly higher in the intestine of high-dose treated fish as compared to the control at exposure week 2 and onwards. Abnormal cytoplasmic extrusions were frequently observed in mucosal folds of high-dose fish at exposure week 4. In the low-dose treatment group, only the expression of PepT-1 was significantly reduced at exposure week 2 and an early adaptive response was observed at exposure week 4. Despite all these intestinal disturbances were reversible in fish upon the abatement to dietary B[a]P (within 1-4 weeks), environmental realistic levels of foodborne B[a]P could induce sublethal toxicity to E. coioides, and probably impose potential risk to the

Induction and recovery of morphofunctional changes in the intestine of juvenile carnivorous fish (Epinephelus coioides) upon exposure to foodborne benzo[a]pyrene

Energy Technology Data Exchange (ETDEWEB)

Yuen, Bonny B.H. [Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Nicholas School of the Environment, Duke University, Durham, NC (United States); Wong, Chris K.C. [Department of Biology, Baptist University of Hong Kong, Waterloo Road, Kowloon, Hong Kong (China); Woo, N Y.S. [Department of Biology, Chinese University of Hong Kong, New Territory, Hong Kong (China); Au, Doris W.T. [Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)

2007-05-15

The sublethal toxicity of dietary benzo[a]pyrene, B[a]P, on fish growth and intestinal morphofunctional changes [as measured by epithelial turnover, cell proliferation, hyperplasia, de novo crypt formation and protein absorption efficiency (i.e. expression of proton/peptide co-transporter, PepT-1, on the mucosal brush border)] were studied for the carnivorous orange-spotted grouper (Epinephelus coioides). Juvenile fish were force-fed daily with pellets containing environmentally realistic concentrations of B[a]P (dissolved in corn oil) at 0.25 {mu}g/g body weight (low-dose) and 12.5 {mu}g/g body weight (high-dose) for 4 weeks, followed by a control diet for a further 4 weeks to assess recovery. Although growth inhibition was observed in fish treated with high-dose B[a]P during the exposure period, no mortality was observed throughout the 8-week experiment. Significant hyperplasia of basal enterocytes of mucosal folds was detected shortly after 3-day exposure to the high-dose B[a]P. Moreover, a faster epithelial turnover was measured in the high-dose B[a]P exposed fish at exposure week 1, which was followed by an increase of basal cell proliferation and a reduction of PepT-1 expression at exposure week 2. The formation of de novo crypts, resemblance to the cancer predisposition syndrome 'juvenile polyposis', was significantly higher in the intestine of high-dose treated fish as compared to the control at exposure week 2 and onwards. Abnormal cytoplasmic extrusions were frequently observed in mucosal folds of high-dose fish at exposure week 4. In the low-dose treatment group, only the expression of PepT-1 was significantly reduced at exposure week 2 and an early adaptive response was observed at exposure week 4. Despite all these intestinal disturbances were reversible in fish upon the abatement to dietary B[a]P (within 1-4 weeks), environmental realistic levels of foodborne B[a]P could induce sublethal toxicity to E. coioides, and probably impose potential risk to

Occupational Exposure Assessment of Nanomaterials using Control Banding Tools

DEFF Research Database (Denmark)

Liguori, Biase

, are relatively advanced, and they are good foundations for an advanced exposure assessment. Considering the tiered approach for workplace assessment proposed by the OECD, these two tools could be situated, between Tier 1 (Information gathering) and Tier 2 (Basic exposure assessment). Moreover, the thesis......Nanotechnology can be termed as the “new industrial revolution”. A broad range of potential benefits in various applications for the environment and everyday life of humans can be related to the use of nanotechnology. Nanomaterials are used in a large variety of products already in the market......, and because of their novel physical and chemical characteristics, the application of nanomaterials is projected to increase further. This will inevitably increase the production of nanomaterials with potential increase of exposure for the workers which are the first in line expected to become exposed...

Selectivity assessment of two biorational insecticides, azadirachtin and pyriproxyfen, in comparison to a neonicotinoid, acetamiprid, on pupae and adults of a Neotropical strain Eretmocerus mundus Mercet.

Science.gov (United States)

Francesena, Natalia; Schneider, Marcela Inés

2018-05-02

Assessment of the susceptibility of natural enemies of pests to selective pesticides is relevant for a sustainable agriculture with low impact on the environment. The aim of this study was to assess the toxicity of two biorational insecticides, azadirachtin and pyriproxyfen in comparison to a neonicotinoid insecticide, acetamiprid, on pupae and adults of a Neotropical strain of Eretmocerus mundus. Adult emergence and survival were evaluated as lethal effects whereas the sublethal effects were assessed through the reproductive capacity, sex ratio, and longevity of the surviving first progeny. Adult emergence from treated pupae was reduced by all three insecticides, but azadirachtin at its maximum field recommended concentration (MFRC) proved the most toxic insecticide. The survival probability of emerged adults was reduced by the three insecticides below than 50% from 2 to 5 days after the adult emergence. Malformations in nonemerged adults from treated pupal hosts were observed at the MFRC of all three insecticides. Sublethal effects on survivors from pupal treatment could be evaluated at only the lowest azadirachtin concentration. At that concentration, though azadirachtin did not affect the reproductive capacity of females, the sex ratio and the longevity of the first progeny were disrupted. The survival of parasitoid adults after adult exposure was reduced by all three insecticides, pyriproxyfen at the MFRC being the most toxic. All insecticides at their half of MFRCs induced sublethal effects in the survivors' adults, with pyriproxyfen being the most harmful to the reproductive capacity of females. In conclusion, both biorational insecticides were toxic to E. mundus. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

Energy Technology Data Exchange (ETDEWEB)

Caudeville, Julien, E-mail: Julien.CAUDEVILLE@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Joint research unit UMR 6599, Heudiasyc (Heuristic and Diagnoses of Complex Systems), University of Technology of Compiegne and CNRS, Rue du Dr Schweitzer, 60200 Compiegne (France); Bonnard, Roseline, E-mail: Roseline.BONNARD@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Boudet, Celine, E-mail: Celine.BOUDET@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Denys, Sebastien, E-mail: Sebastien.DENYS@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Govaert, Gerard, E-mail: gerard.govaert@utc.fr [Joint research unit UMR 6599, Heudiasyc (Heuristic and Diagnoses of Complex Systems), University of Technology of Compiegne and CNRS, Rue du Dr Schweitzer, 60200 Compiegne (France); Cicolella, Andre, E-mail: Andre.CICOLELLA@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France)

2012-08-15

Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: -identify and manage geographic areas where hotspot exposures are a potential risk to human health; and -reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km{sup 2} regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. -- Highlights: Black-Right-Pointing-Pointer We present a multimedia exposure model for mapping environmental disparities. Black-Right-Pointing-Pointer We perform a risk assessment on a region of France at a fine scale for three metals. Black-Right-Pointing-Pointer We

Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

International Nuclear Information System (INIS)

Caudeville, Julien; Bonnard, Roseline; Boudet, Céline; Denys, Sébastien; Govaert, Gérard; Cicolella, André

2012-01-01

Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: -identify and manage geographic areas where hotspot exposures are a potential risk to human health; and -reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km 2 regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. -- Highlights: ► We present a multimedia exposure model for mapping environmental disparities. ► We perform a risk assessment on a region of France at a fine scale for three metals. ► We examine exposure determinants and detect vulnerable population. ► The largest

Nano-metal oxides: Exposure and engineering control assessment.

Science.gov (United States)

Garcia, Alberto; Eastlake, Adrienne; Topmiller, Jennifer L; Sparks, Christopher; Martinez, Kenneth; Geraci, Charles L

2017-09-01

In January 2007, the National Institute for Occupational Safety and Health (NIOSH) conducted a field study to evaluate process specific emissions during the production of ENMs. This study was performed using the nanoparticle emission assessment technique (NEAT). During this study, it was determined that ENMs were released during production and cleaning of the process reactor. Airborne concentrations of silver, nickel, and iron were found both in the employee's personal breathing zone and area samples during reactor cleaning. At the completion of this initial survey, it was suggested that a flanged attachment be added to the local exhaust ventilation system.  NIOSH re-evaluated the facility in December 2011 to assess worker exposures following an increase in production rates. This study included a fully comprehensive emissions, exposure, and engineering control evaluation of the entire process. This study made use of the nanoparticle exposure assessment technique (NEAT 2.0). Data obtained from filter-based samples and direct reading instruments indicate that reactor cleanout increased the overall particle concentration in the immediate area. However, it does not appear that these concentrations affect areas outside of the production floor. As the distance between the reactor and the sample location increased, the observed particle number concentration decreased, creating a concentration gradient with respect to the reactor. The results of this study confirm that the flanged attachment on the local exhaust ventilation system served to decrease exposure potential.  Given the available toxicological data of the metals evaluated, caution is warranted. One should always keep in mind that occupational exposure levels were not developed specifically for nanoscale particles. With data suggesting that certain nanoparticles may be more toxic than the larger counterparts of the same material; employers should attempt to control emissions of these particles at the source

Health effects assessment of chemical exposures: ARIES methodology

Energy Technology Data Exchange (ETDEWEB)

Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

1995-07-01

In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs.

Health effects assessment of chemical exposures: ARIES methodology

International Nuclear Information System (INIS)

Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

1995-01-01

In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs

Population-Based Assessment of Exposure to Risk Behaviors in Motion Pictures.

Science.gov (United States)

Sargent, James D; Worth, Keilah A; Beach, Michael; Gerrard, Meg; Heatherton, Todd F

2008-01-01

The aim of most population-based studies of media is to relate a specific exposure to an outcome of interest. A research program has been developed that evaluates exposure to different components of movies in an attempt of assess the association of such exposure with the adoption of substance use during adolescence. To assess exposure to movie substance use, one must measure both viewing time and content. In developing the exposure measure, the study team was interested in circumventing a common problem in exposure measurement, where measures often conflate exposure to media with attention to media. Our aim in this paper is to present a validated measure of exposure to entertainment media, the Beach method, which combines recognition of a movie title with content analysis of the movie for substance use, to generate population based measures of exposure to substance use in this form of entertainment.

Assessment of exposure to shiftwork mechanisms in the general population: the development of a new job-exposure matrix.

Science.gov (United States)

Fernandez, Renae C; Peters, Susan; Carey, Renee N; Davies, Michael J; Fritschi, Lin

2014-10-01

To develop a job-exposure matrix (JEM) that estimates exposure to eight variables representing different aspects of shiftwork among female workers. Occupational history and shiftwork exposure data were obtained from a population-based breast cancer case-control study. Exposure to light at night, phase shift, sleep disturbances, poor diet, lack of physical activity, lack of vitamin D, and graveyard and early morning shifts, was calculated by occupational code. Three threshold values based on the frequency of exposure were considered (10%, 30% and 50%) for use as cut-offs in determining exposure for each occupational code. JEM-based exposure classification was compared with that from the OccIDEAS application (job-specific questionnaires and assessment by rules) by assessing the effect on the OR for phase shift and breast cancer. Using data from the Australian Workplace Exposure Study, the specificity and sensitivity of the threshold values were calculated for each exposure variable. 127 of 413 occupational codes involved exposure to one or more shiftwork variables. Occupations with the highest probability of exposure shiftwork included nurses and midwives. Using the 30% threshold, the OR for the association between phase shift exposure and breast cancer was decreased and no longer statistically significant (OR=1.14, 95% CI 0.92 to 1.42). The 30% cut-off point demonstrated best specificity and sensitivity, although results varied between exposure variables. This JEM provides a set of indicators reflecting biologically plausible mechanisms for the potential impact of shiftwork on health and may provide an alternative method of exposure assessment in the absence of detailed job history and exposure data. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Toxicity assessment of unintentional exposure to multiple chemicals

International Nuclear Information System (INIS)

Mumtaz, M.M.; Ruiz, P.; De Rosa, C.T.

2007-01-01

Typically exposure to environmental chemicals is unintentional, and often the exposure is to chemical mixtures, either simultaneously or sequentially. When exposure occurs, in public health practice, it is prudent to ascertain if thresholds for harmful health effects are exceeded, whether by individual chemicals or by chemicals in combination. Three alternative approaches are available for assessing the toxicity of chemical mixtures. Each approach, however, has shortcomings. As the procedures of each approach are described in this paper, at various steps research needs are identified. Recently, reliance has increased on computational toxicology methods for predicting toxicological effects when data are limited. Advances in molecular biology, identification of biomarkers, and availability of accurate and sensitive methods allow us to more precisely define the relationships between multiple chemical exposures and health effects, both qualitatively and quantitatively. Key research needs are best fulfilled through collaborative research. It is through such collaborations that resources are most effectively leveraged to further develop and apply toxicity assessment methods that advance public health practices in vulnerable communities

Stakeholder attitudes towards cumulative and aggregate exposure assessment of pesticides.

Science.gov (United States)

Verbeke, Wim; Van Loo, Ellen J; Vanhonacker, Filiep; Delcour, Ilse; Spanoghe, Pieter; van Klaveren, Jacob D

2015-05-01

This study evaluates the attitudes and perspectives of different stakeholder groups (agricultural producers, pesticide manufacturers, trading companies, retailers, regulators, food safety authorities, scientists and NGOs) towards the concepts of cumulative and aggregate exposure assessment of pesticides by means of qualitative in-depth interviews (n = 15) and a quantitative stakeholder survey (n = 65). The stakeholders involved generally agreed that the use of chemical pesticides is needed, primarily for meeting the need of feeding the growing world population, while clearly acknowledging the problematic nature of human exposure to pesticide residues. Current monitoring was generally perceived to be adequate, but the timeliness and consistency of monitoring practices across countries were questioned. The concept of cumulative exposure assessment was better understood by stakeholders than the concept of aggregate exposure assessment. Identified pitfalls were data availability, data limitations, sources and ways of dealing with uncertainties, as well as information and training needs. Regulators and food safety authorities were perceived as the stakeholder groups for whom cumulative and aggregate pesticide exposure assessment methods and tools would be most useful and acceptable. Insights obtained from this exploratory study have been integrated in the development of targeted and stakeholder-tailored dissemination and training programmes that were implemented within the EU-FP7 project ACROPOLIS. Copyright © 2014 Elsevier Ltd. All rights reserved.

Probabilistic assessment of exposure to hair cosmetic products by the French population.

Science.gov (United States)

Ficheux, A S; Bernard, A; Chevillotte, G; Dornic, N; Roudot, A C

2016-06-01

Cosmetic exposure data are limited in Europe and especially in France. The aim of this study was to assess the exposure to hair cosmetics using recent consumption data (percentage of users, frequency of use and amount per use) generated for the French population (Ficheux et al., 2015, 2016). Exposure was assessed using a probabilistic method for eleven hair products: liquid shampoo, dry shampoo, conditioner, hair mask, hair serum, hair oil, styling lacquer, styling gel, styling foam, styling wax and styling spray. Exposure was assessed by sex and by age classes in adults and children. Pregnant women were also studied. For liquid shampoo, conditioner and some styling products (gel, lacquer and foam), the levels of exposure were higher than the values currently used by the Scientific Committee on Consumer Safety (SCCS). Exposure values found for styling wax and styling spray were lower than SCCS values. Exposure was assessed for the first time for dry shampoo, hair mask, hair serum and hair oil products. These new French exposure values will be useful for safety assessors and for safety agencies in order to protect the general population and these at-risk populations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gene expression in Listeria monocytogenes exposed to sublethal concentration of benzalkonium chloride.

Science.gov (United States)

Tamburro, Manuela; Ripabelli, Giancarlo; Vitullo, Monia; Dallman, Timothy James; Pontello, Mirella; Amar, Corinne Francoise Laurence; Sammarco, Michela Lucia

2015-06-01

In this study, tolerance at sublethal concentration of benzalkonium chloride and transcription levels of mdrL, ladR, lde, sigB and bcrABC genes in Listeria monocytogenes strains were evaluated. Viable cells reduction occurred in 45% of strains and clinical isolates showed lower sensitivity than isolates from foods. An increased transcription of an efflux system encoding gene was found in 60% of strains, and simultaneous mdrL overexpression and ladR underexpression occurred in 30% of isolates. A significant association between reduced benzalkonium chloride activity and both mdrL and sigB overexpression was observed; sigB expression also correlated with both mdrL and ladR genes. The bcrABC gene was only found in six strains, all isolated from foods and sensitive to benzalkonium chloride, and in four strains an underexpression was observed. Disinfection at sublethal concentration was less effective in clinical isolates, and mdrL and sigB expression was significantly affected by disinfection. Further insights are needed to understand the adaptation to benzalkonium chloride and to evaluate whether changes in gene expression could affect the L. monocytogenes virulence traits and persistence in the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Assessing the sublethal effects of in-river concentrations of parameters contributing to cumulative effects in the Athabasca river basin using a fathead minnow bioassay.

Science.gov (United States)

Squires, Allison J; Dubé, Monique G; Rozon-Ramilo, Lisa D

2013-03-01

The Athabasca River basin, located in Alberta, Canada, covers 157, 000 km(2) and holds significant cultural and economic importance. Recent research assessed changes in several water quality and quantity parameters that have changed both spatially (along the river continuum) and temporally (pre-development and present day) in the Athabasca River Basin. In particular, parameters such as salinity and dissolved sulphate have changed significantly across the Athabasca River mainstem over the past five decades. Further laboratory testing has linked concentrations of these parameters to changes in fathead minnow reproduction. Research is required to determine whether these changes observed in the laboratory can be applied to actual in-river conditions. The objectives of the present study were to twofold: assess changes in fathead minnow response metrics (i.e., condition, liver and gonad size, egg production, and gill histology) associated with increasing concentrations of salinity and dissolved sulphate and determine whether sublethal effect thresholds established in laboratory experiments correspond to actual in-river concentrations using water from the mouth and headwaters of the Athabasca River. Three dose-response experiments (NaCl, SO4, and water sampled from the mouth of the Athabasca River) were conducted at Jasper National Park, Alberta, Canada. Significant increases in mean eggs per female per day occurred at the 50% treatment for the mouth experiment and thresholds previously developed in the laboratory were verified. Copyright © 2012 SETAC.

Performance of GPS-devices for environmental exposure assessment.

Science.gov (United States)

Beekhuizen, Johan; Kromhout, Hans; Huss, Anke; Vermeulen, Roel

2013-01-01

Integration of individual time-location patterns with spatially resolved exposure maps enables a more accurate estimation of personal exposures to environmental pollutants than using estimates at fixed locations. Current global positioning system (GPS) devices can be used to track an individual's location. However, information on GPS-performance in environmental exposure assessment is largely missing. We therefore performed two studies. First, a commute-study, where the commute of 12 individuals was tracked twice, testing GPS-performance for five transport modes and two wearing modes. Second, an urban-tracking study, where one individual was tracked repeatedly through different areas, focused on the effect of building obstruction on GPS-performance. The median error from the true path for walking was 3.7 m, biking 2.9 m, train 4.8 m, bus 4.9 m, and car 3.3 m. Errors were larger in a high-rise commercial area (median error=7.1 m) compared with a low-rise residential area (median error=2.2 m). Thus, GPS-performance largely depends on the transport mode and urban built-up. Although ~85% of all errors were 50 m. Modern GPS-devices are useful tools for environmental exposure assessment, but large GPS-errors might affect estimates of exposures with high spatial variability.

Stoffenmanager exposure model: company-specific exposure assessments using a Bayesian methodology.

NARCIS (Netherlands)

Ven, P. van de; Fransman, W.; Schinkel, J.; Rubingh, C.; Warren, N.; Tielemans, E.

2010-01-01

The web-based tool "Stoffenmanager" was initially developed to assist small- and medium-sized enterprises in the Netherlands to make qualitative risk assessments and to provide advice on control at the workplace. The tool uses a mechanistic model to arrive at a "Stoffenmanager score" for exposure.

Current Pesticide Risk Assessment Protocols Do Not Adequately Address Differences Between Honey Bees (Apis mellifera and Bumble Bees (Bombus spp.

Directory of Open Access Journals (Sweden)

Kimberly Stoner

2016-12-01

Full Text Available Recent research has demonstrated colony-level sublethal effects of imidacloprid on bumble bees, affecting foraging and food consumption, and thus colony growth and reproduction, at lower pesticide concentrations than for honey bee colonies. However, these studies may not reflect the full effects of neonicotinoids on bumble bees because bumble bee life cycles are different from those of honey bees. Unlike honey bees, bumble bees live in colonies for only a few months each year. Assessing the sublethal effects of systemic insecticides only on the colony level is appropriate for honey bees, but for bumble bees, this approach addresses just part of their annual life cycle. Queens are solitary from the time they leave their home colonies in fall until they produce their first workers the following year. Queens forage for pollen and nectar, and are thus exposed to more risk of direct pesticide exposure than honey bee queens. Almost no research has been done on pesticide exposure to and effects on bumble bee queens. Additional research should focus on critical periods in a bumble bee queen’s life which have the greatest nutritional demands, foraging requirements, and potential for exposure to pesticides, particularly the period during and after nest establishment in the spring when the queen must forage for the nutritional needs of her brood and for her own needs while she maintains an elevated body temperature in order to incubate the brood.

Sublethal Ciprofloxacin Treatment Leads to Rapid Development of High-Level Ciprofloxacin Resistance during Long-Term Experimental Evolution of Pseudomonas aeruginosa

Science.gov (United States)

Jørgensen, Karin Meinike; Wassermann, Tina; Jensen, Peter Østrup; Hengzuang, Wang; Molin, Søren; Høiby, Niels

2013-01-01

The dynamics of occurrence and the genetic basis of ciprofloxacin resistance were studied in a long-term evolution experiment (940 generations) in wild-type, reference strain (PAO1) and hypermutable (PAOΔmutS and PAOMY-Mgm) P. aeruginosa populations continuously exposed to sub-MICs (1/4) of ciprofloxacin. A rapid occurrence of ciprofloxacin-resistant mutants (MIC of ≥12 μg/ml, representing 100 times the MIC of the original population) were observed in all ciprofloxacin-exposed lineages of PAOΔmutS and PAOMY-Mgm populations after 100 and 170 generations, respectively, and in one of the PAO1 lineages after 240 generations. The genetic basis of resistance was mutations in gyrA (C248T and G259T) and gyrB (C1397A). Cross-resistance to beta-lactam antibiotics was observed in the bacterial populations that evolved during exposure to sublethal concentrations of ciprofloxacin. Our study shows that mutants with high-level ciprofloxacin resistance are selected in P. aeruginosa bacterial populations exposed to sub-MICs of ciprofloxacin. This can have implications for the long-term persistence of resistant bacteria and spread of antibiotic resistance by exposure of commensal bacterial flora to low antibiotic concentrations. PMID:23774442

Potential hepatic toxicity of buprofezin at sublethal concentrations: ROS-mediated conversion of energy metabolism.

Science.gov (United States)

Ji, Xiaotong; Ku, Tingting; Zhu, Na; Ning, Xia; Wei, Wei; Li, Guangke; Sang, Nan

2016-12-15

Buprofezin is known for its broad-spectrum action and environmental safety. The popularity of buprofezin has raised concerns about its potentially adverse effects on human health and risk to the environment. In this study, we first identified the liver as one of the major organs in which buprofezin accumulated, and we detected a severe oxidative stress response. Next, we demonstrated that sublethal concentrations of buprofezin promoted the conversion of energy metabolism from the aerobic tricarboxylic acid (TCA) cycle and oxidative phosphorylation to anaerobic glycolysis. Importantly, reactive oxygen species (ROS) generation partially accounted for the shunting of the energy metabolism through the buprofezin-mediated inhibition of cytochrome c oxidase activity. ROS directly perturbed the activities of several key TCA cycle enzymes, stimulated glycolysis, and indirectly disturbed the activity of the respiratory chain complex by altering mitochondrial DNA (mtDNA). These findings clarify the potential mechanisms of buprofezin toxicity and provide biomarkers for buprofezin-mediated hepatotoxicity at sublethal concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

Directory of Open Access Journals (Sweden)

OLIVIA ANCA RUSU

2011-03-01

Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 μg/m³. Health assessment of a group of 49 workers was based on questionnaire interview, determination of TDI antibodies and lung function tests. Data collected until this stage do not show any negative effects of TDI on the employees health. Since this plant had only recently begun operating, continuous workplace and ambient air TDI monitoring, along with workers health surveillance, is deemed necessary.

Framework for Multi-Pathway Cumulative Exposure for Comparative Assessments

DEFF Research Database (Denmark)

McKone, Tom; Fantke, Peter

2016-01-01

in comparative risk assessment, life-cycle assessment (LCA), and chemical alternatives assessment (CAA), multimedia fate and exposure models synthesize information about partitioning, reaction, and intermedia-transport properties of chemicals in a representative (local to regional) or generic (continental...

Assessment of dermal exposure to chemicals

NARCIS (Netherlands)

Hemmen, J.J. van; Brouwer, D.H.

1995-01-01

The methods for the dermal exposure assessment vary in their complexity and are in some sense complementary to each other. The most easy-to-use methods involve a pseudo-skin-approach, such as gloves and removal by washing. In some cases generic modelling appears to be possible. The experimental

A proteomic evaluation of the effects of the pharmaceuticals diclofenac and gemfibrozil on marine mussels (Mytilus spp.): evidence for chronic sublethal effects on stress-response proteins.

Science.gov (United States)

Schmidt, Wiebke; Rainville, Louis-Charles; McEneff, Gillian; Sheehan, David; Quinn, Brian

2014-03-01

Human pharmaceuticals (e.g. the lipid regulator gemfibrozil and the non-steroidal anti-inflammatory drug diclofenac) are an emerging environmental threat in the aquatic environment. This study aimed to evaluate sublethal effects of these two commonly found pharmaceuticals on the protein profiles of marine mussels (Mytilus spp.). Mytilus spp. was exposed to environmentally relevant and elevated concentrations (1 and 1000 µg/l respectively) of both drugs for 14 days. In addition, mussels were maintained for seven days post treatment to examine the potential of blue mussels to recover from such an exposure. Differential protein expression signatures (PES) in the digestive gland of mussels were obtained using two-dimensional gel electrophoresis after 7, 14, and 21 days of exposure. Twelve spots were significantly increased or decreased by gemfibrozil and/or diclofenac, seven of which were successfully identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. These proteins were involved in energy metabolism, oxidative stress response, protein folding, and immune responses. Changes in the PES over time suggested that mussels were still experiencing oxidative stress for up to seven days post exposure. In addition, a suite of biomarkers comprising glutathione transferase, lipid peroxidation, and DNA damage were studied. An oxidative stress response was confirmed by biomarker responses. To our knowledge, this is the first investigation using proteomics to assess the potential effects of human pharmaceuticals on a non-target species in an environmentally-relevant model. The successful application of this proteomic approach supports its potential use in pollution biomonitoring and highlights its ability to aid in the discovery of new biomarkers. Copyright © 2013 John Wiley & Sons, Ltd.

Sublethal Concentrations of Carbapenems Alter Cell Morphology and Genomic Expression of Klebsiella pneumoniae Biofilms

Science.gov (United States)

Van Laar, Tricia A.; Chen, Tsute; You, Tao

2015-01-01

Klebsiella pneumoniae, a Gram-negative bacterium, is normally associated with pneumonia in patients with weakened immune systems. However, it is also a prevalent nosocomial infectious agent that can be found in infected surgical sites and combat wounds. Many of these clinical strains display multidrug resistance. We have worked with a clinical strain of K. pneumoniae that was initially isolated from a wound of an injured soldier. This strain demonstrated resistance to many commonly used antibiotics but sensitivity to carbapenems. This isolate was capable of forming biofilms in vitro, contributing to its increased antibiotic resistance and impaired clearance. We were interested in determining how sublethal concentrations of carbapenem treatment specifically affect K. pneumoniae biofilms both in morphology and in genomic expression. Scanning electron microscopy showed striking morphological differences between untreated and treated biofilms, including rounding, blebbing, and dimpling of treated cells. Comparative transcriptome analysis using RNA sequencing (RNA-Seq) technology identified a large number of open reading frames (ORFs) differentially regulated in response to carbapenem treatment at 2 and 24 h. ORFs upregulated with carbapenem treatment included genes involved in resistance, as well as those coding for antiporters and autoinducers. ORFs downregulated included those coding for metal transporters, membrane biosynthesis proteins, and motility proteins. Quantitative real-time PCR validated the general trend of some of these differentially regulated ORFs. Treatment of K. pneumoniae biofilms with sublethal concentrations of carbapenems induced a wide range of phenotypic and gene expression changes. This study reveals some of the mechanisms underlying how sublethal amounts of carbapenems could affect the overall fitness and pathogenic potential of K. pneumoniae biofilm cells. PMID:25583711

Effect of acute pesticide exposure on bee spatial working memory using an analogue of the radial-arm maze

Science.gov (United States)

Samuelson, Elizabeth E. W.; Chen-Wishart, Zachary P.; Gill, Richard J.; Leadbeater, Ellouise

2016-12-01

Pesticides, including neonicotinoids, typically target pest insects by being neurotoxic. Inadvertent exposure to foraging insect pollinators is usually sub-lethal, but may affect cognition. One cognitive trait, spatial working memory, may be important in avoiding previously-visited flowers and other spatial tasks such as navigation. To test this, we investigated the effect of acute thiamethoxam exposure on spatial working memory in the bumblebee Bombus terrestris, using an adaptation of the radial-arm maze (RAM). We first demonstrated that bumblebees use spatial working memory to solve the RAM by showing that untreated bees performed significantly better than would be expected if choices were random or governed by stereotyped visitation rules. We then exposed bees to either a high sub-lethal positive control thiamethoxam dose (2.5 ng-1 bee), or one of two low doses (0.377 or 0.091 ng-1) based on estimated field-realistic exposure. The high dose caused bees to make more and earlier spatial memory errors and take longer to complete the task than unexposed bees. For the low doses, the negative effects were smaller but statistically significant, and dependent on bee size. The spatial working memory impairment shown here has the potential to harm bees exposed to thiamethoxam, through possible impacts on foraging efficiency or homing.

Assessing caffeine as an emerging environmental concern using conventional approaches.

Science.gov (United States)

Moore, M T; Greenway, S L; Farris, J L; Guerra, B

2008-01-01

Organic wastewater contaminants, including pharmaceuticals, caffeine, and nicotine, have received increased scrutiny because of their detection in water bodies receiving wastewater discharge. Despite recent measurement in United States streams, caffeine's effect on freshwater organisms is not well documented. The present study measured caffeine's lethal and sublethal effects on the freshwater species, Ceriodaphnia dubia, Pimephales promelas, and Chironomus dilutus. These organisms, which are used in standard testing or effluent monitoring, were exposed to aqueous caffeine solutions under static exposure for 48 hours and daily renewed static exposure for 7 days. Averaged responses of 48-hour acute end points indicated that C. dubia was more sensitive to caffeine exposures (LC50 = 60 mg/L) than either P. promelas (LC50 = 100 mg/L) or C. dilutus (LC50 = 1,230 mg/L). Exposure-response slopes confirmed these findings (3% mortality/mg/L for C. dubia; 0.5% mortality/mg/L for P. promelas; and 0.07% mortality/mg/L for C. dilutus). Comparative 7-day responses between C. dubia and P. promelas (LC50 = 46 and 55 mg/L, respectively) were more similar than the broad range of acute values. Sublethal effects measured for caffeine exposure included impaired C. dubia reproduction (IC50 = 44 mg/L) and inhibited P. promelas growth (IC50 = 71 mg/L). According to the results of this study, combined with earlier studies reporting environmental concentrations and product half-lives, caffeine should pose negligible risk for most aquatic vertebrate and invertebrate organisms.

Harmonizing exposure metrics and methods for sustainability assessments of food contact materials

DEFF Research Database (Denmark)

Ernstoff, Alexi; Jolliet, Olivier; Niero, Monia

2016-01-01

) and Cradle to Cradle to support packaging design. Each assessment has distinct context and goals, but can help manage exposure to toxic chemicals and other environmental impacts. Metrics a nd methods to quantify and characterize exposure to potentially toxic chemicals specifically in food packaging are......, however, notably lacking from such assessments. Furthermore, previous case studies demonstrated that sustainable packaging design focuses, such as decreasing greenhouse gas emissions or resource consumption, can increase exposure to toxic chemicals through packaging. Thereby, developing harmonized methods...... for quantifying exposure to chemicals in food packaging is critical to ensure ‘sustainable packages’ do not increase exposure to toxic chemicals. Therefore we developed modelling methods suitable for first-tier risk screening and environmental assessments. The modelling framework was based on the new product...

Assessment of health impacts of radon exposures in Florida

International Nuclear Information System (INIS)

Vonstille, W.T.; Sacarello, H.L.A.

1990-01-01

This paper reports on residential radon levels, from a statewide Florida survey, that were used in an analysis of over 150,000 medically treated episodes of malignancies and other serious illnesses and conditions in whites, blacks and Hispanics from all counties in the state. No evidence of an increased percentage of cancer was found in any sex or ethnic group from the areas with the highest radon exposure levels. Age adjustment of data did not affect the results. The highest radon exposures were associated with some of the lowest cancer rates and contradict the risk assessment hypothesis based on extrapolation from exposures in mining. Points for DOE and EPA errors in risk assessment methods are reviewed; predictions from risk assessment should be empirically tested as in the case of any other scientific hypothesis before being used as a basis for public policy. Thus, the authors find that cancer risks of residential radon have been vastly overstated

A review of air exchange rate models for air pollution exposure assessments.

Science.gov (United States)

Breen, Michael S; Schultz, Bradley D; Sohn, Michael D; Long, Thomas; Langstaff, John; Williams, Ronald; Isaacs, Kristin; Meng, Qing Yu; Stallings, Casson; Smith, Luther

2014-11-01

A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings where people spend their time. The AER, which is the rate of exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pollutants and for removal of indoor-emitted air pollutants. This paper presents an overview and critical analysis of the scientific literature on empirical and physically based AER models for residential and commercial buildings; the models highlighted here are feasible for exposure assessments as extensive inputs are not required. Models are included for the three types of airflows that can occur across building envelopes: leakage, natural ventilation, and mechanical ventilation. Guidance is provided to select the preferable AER model based on available data, desired temporal resolution, types of airflows, and types of buildings included in the exposure assessment. For exposure assessments with some limited building leakage or AER measurements, strategies are described to reduce AER model uncertainty. This review will facilitate the selection of AER models in support of air pollution exposure assessments.

Multibiomarker assessment of cerium dioxide nanoparticle (nCeO{sub 2}) sublethal effects on two freshwater invertebrates, Dreissena polymorpha and Gammarus roeseli

Energy Technology Data Exchange (ETDEWEB)

Garaud, M. [Université de Lorraine, CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Campus Bridoux, Rue du Général Delestraint, 57070 Metz (France); International Consortium for the Environmental Implications of Nanotechnology (iCEINT), Aix en Provence (France); Trapp, J.; Devin, S.; Cossu-Leguille, C.; Pain-Devin, S.; Felten, V. [Université de Lorraine, CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Campus Bridoux, Rue du Général Delestraint, 57070 Metz (France); Giamberini, L., E-mail: laure.giamberini@univ-lorraine.fr [Université de Lorraine, CNRS UMR 7360, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Campus Bridoux, Rue du Général Delestraint, 57070 Metz (France); International Consortium for the Environmental Implications of Nanotechnology (iCEINT), Aix en Provence (France)

2015-01-15

Highlights: • Gammarids and mussels both accumulated significant amount of waterborne nCeO{sub 2}. • nCeO{sub 2} decreased catalase, lysosomal system size and lipoperoxidation in mussels. • nCeO{sub 2} could exert antioxidant protecting activity in mussels. • In contrast with mussels, no effects of nCeO{sub 2} were observed on Gammarids. - Abstract: Cerium nanoparticles (nCeO{sub 2}) are widely used in everyday products, as fuel and paint additives. Meanwhile, very few studies on nCeO{sub 2} sublethal effects on aquatic organisms are available. We tried to fill this knowledge gap by investigating short-term effects of nCeO{sub 2} at environmentally realistic concentrations on two freshwater invertebrates; the amphipod Gammarus roeseli and the bivalve Dreissena polymorpha, using an integrated multibiomarker approach to detect early adverse effects of nCeO{sub 2} on organism biology. Differences in the behaviour of the organisms and of nanoparticles in the water column led to differential nCeO{sub 2} bioaccumulations, G. roeseli accumulating more cerium than D. polymorpha. Exposure to nCeO{sub 2} led to decreases in the size of the lysosomal system, catalase activity and lipoperoxidation in mussel digestive glands that could result from nCeO{sub 2} antioxidant properties, but also negatively impacted haemolymph ion concentrations. At the same time, no strong adverse effects of nCeO{sub 2} could be observed on G. roeseli. Further experiments will be necessary to confirm the absence of severe nCeO{sub 2} adverse effects in long-term environmentally realistic conditions.

Analysis of persistent changes to γ-aminobutyric acid receptor gene expression in Plutella xylostella subjected to sublethal amounts of spinosad.

Science.gov (United States)

Yin, X-H; Wu, Q-J; Zhang, Y-J; Long, Y-H; Wu, X-M; Li, R-Y; Wang, M; Tian, X-L; Jiao, X-G

2016-07-25

A multi-generational approach was used to investigate the persistent effects of a sub-lethal dose of spinosad in Plutella xylostella. The susceptibility of various sub-populations of P. xylostella to spinosad and the effects of the insecticide on the gene expression of γ-aminobutyric acid receptor (GABAR) were determined. The results of a leaf dip bioassay showed that the sensitivity of P. xylostella to spinosad decreased across generations. The sub-strains had been previously selected based on a determined LC25 of spinosad. Considering that GABA-gated chloride channels are the primary targets of spinosad, the cDNA of P. xylostella was used to clone GABARα by using reverse transcription-polymerase chain reaction (RT-PCR). The mature peptide cDNA was 1477-bp long and contained a 1449-bp open reading frame encoding a protein of 483 amino acids. The resulting amino acid sequence was used to generate a neighbor-joining dendrogram, and homology search was conducted using NCBI BLAST. The protein had high similarity with the known GABAR sequence from P. xylostella. Subsequent semi-quantitative RT-PCR and real-time PCR analyses indicated that the GABAR transcript levels in the spinosad-resistant strain (RR, 145.82-fold) and in Sub1 strain (selected with LC25 spinosad for one generation) were the highest, followed by those in the spinosad-susceptible strain, the Sub10 strain (selected for ten generations), and the Sub5 strain (selected for five generations). This multi-generational study found significant correlations between spinosad susceptibility and GABAR gene expression, providing insights into the long-term effects of sub-lethal insecticide exposure and its potential to lead to the development of insecticide-resistant insect populations.

Radioprotection of mice by lactoferrin against irradiation with sublethal X-rays

International Nuclear Information System (INIS)

Nishimura, Yoshikazu; Homma-Takeda, Shino; Kim, Hee-Sun; Kakuta, Izuru

2014-01-01

The influence of a host defense protein, lactoferrin (LF), contained in exocrine secretions such as milk, on radiation disorder was investigated. A total of 25 C3H/He mice in each of two groups were maintained with 0.1% LF-added and LF-free diets, respectively, for one month. The mice were then treated with single whole-body X-ray irradiation at a sublethal dose (6.8 Gy), and the survival rate after irradiation was investigated. The survival rate at 30 d after irradiation was relatively higher in the LF group than in the control group (LF-free), (85 and 62%, respectively). The body weight 15 d after X-ray irradiation was also significantly greater in the LF group than in the control group. The hemoglobin level and hematocrit value were higher in the LF group at 5 d before X-ray irradiation. Another 52 mice underwent whole-body X-ray irradiation at the sublethal dose (6.8 Gy), and then LF was intraperitoneally injected once at 4 mg/animal to half of them. The survival rate in LF-treated mice 30 d after irradiation was 92%, significantly higher than in mice treated with saline (50%) (P = 0.0012). In addition, LF showed hydroxyl radical scavenger activity in vitro. These findings suggest that LF may inhibit radiation damage. (author)

Evaluation of erythrocyte delta-amino levulinic acid dehydratase activity as a short-term indicator in fish of a harmful exposure to lead

Energy Technology Data Exchange (ETDEWEB)

Hodson, P.V.; Blunt, B.R.; Spry, D.J.; Austen, K.

1977-04-01

The activity of erythrocyte delta-amino levulinic acid dehydratase (ALA-D) of fish is easily measured under a variety of experimental conditions. Exposure of rainbow trout (Salmo gairdneri), brook trout (Salvelinus fontinalis), goldfish (Carassius auratus), and pumpkinseeds (Lepomis gibbosus) to lead consistently inhibited ALA-D within 2 wks at concentrations as low as 10, 90, 470, and 90 ..mu..g/l, respectively. In rainbow and brook trout these concentrations were closely related to the published minimum effective concentrations causing sublethal harm. There was a significant linear relationship between ALA-D activity and log of blood lead concentration, between ALA-D activity and log of lead in water, and between blood lead and lead in water. Near lethal exposures to cadmium, copper, zinc, and mercury did not significantly inhibit ALA-D activity. Recovery of ALA-D activity of rainbow trout after transfer from 120 ..mu..g/l lead to clean water occurred in 8 wk. This enzyme provides fast, consistent, specific, and sensitive estimates of lead concentrations causing sublethal harm to fish and may help to relate sources of lead to degree of exposure of fish populations in the field.

Dermal exposure assessment to benzene and toluene using charcoal cloth pads

NARCIS (Netherlands)

Wendel de Joode, B. van; Tielemans, E.; Vermeulen, R.; Wegh, H.; Kromhout, H.

2005-01-01

Charcoal cloth pads have been used to assess volatile chemicals on the skin in a laboratory setting; however, they have not yet been applied to measure dermal exposure in occupational settings. This study aimed at evaluating whether charcoal pads can be used to assess dermal exposure to benzene and

Effect of sublethal preculturing on the survival of probiotics and metabolite formation in set-yoghurt

NARCIS (Netherlands)

Settachaimongkon, S.; Valenberg, van H.J.F.; Winata, V.; Wang, X.; Nout, M.J.R.; Hooijdonk, van A.C.M.; Zwietering, M.H.; Smid, E.J.

2015-01-01

The objective of this study was to investigate the effect of preculturing of Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB12 under sublethal stress conditions on their survival and metabolite formation in set-yoghurt. Prior to co-cultivation with yoghurt starters in milk,

Growth Responses of Fish During Chronic Exposure of Metal Mixture under Laboratory Conditions

Directory of Open Access Journals (Sweden)

Saima Naz and Muhammad Javed

2013-07-01

Full Text Available Growth responses of five fish species viz. Catla catla, Labeo rohita, Cirrhina mrigala, Ctenopharyngodon idella and Hypophthalmichthys molitrix were determined, separately, under chronic exposure of binary mixture of metals (Zn+Ni at sub-lethal concentrations (1/3rd of LC50 for 12 weeks. Randomized complete block design (RCBD was followed to conduct this research work. The groups (10 fish each of Catla catla, Labeo rohita, Cirrhina mrigala, Ctenopharyngodon idella and Hypophthalmichthys molitrix having almost similar weights were investigated for their growth responses and metals bioaccumulation patterns in their body organs during chronic exposure of Zn+Ni mixture. The bioaccumulation of metals in the fish body organs viz. gills, liver, kidney, fins, bones, muscle and skin were also determined before and after growth trails under the stress of metals mixture. The exposure of fish to sub-lethal concentrations of mixture caused significant impacts on the average wet weight increments of five fish species. Ctenopharyngodon idella and Labeo rohita attained significantly higher weights, followed by that of Hypophthalmichthys molitrix, Cirrhina mrigala and Catla catla. However, the growth of metals mixture exposed fish species was significantly lesser than that of control fish (un-stressed. Significantly variable condition factor values reflected the degree of fish well-beings that correlated directly with fish growth and metal exposure concentration. Any significant change in feed intake, due to stress, is reflected in terms of fish growth showing the impacts of metal mixture on fish growth were either additive or antagonist / synergistic. Accumulation of all the metals in fish body followed the general order: liver>kidney>gills> skin >muscle> fins >bones.

Range-finding risk assessment of inhalation exposure to nanodiamonds in a laboratory environment.

Science.gov (United States)

Koivisto, Antti J; Palomäki, Jaana E; Viitanen, Anna-Kaisa; Siivola, Kirsi M; Koponen, Ismo K; Yu, Mingzhou; Kanerva, Tomi S; Norppa, Hannu; Alenius, Harri T; Hussein, Tareq; Savolainen, Kai M; Hämeri, Kaarle J

2014-05-16

This study considers fundamental methods in occupational risk assessment of exposure to airborne engineered nanomaterials. We discuss characterization of particle emissions, exposure assessment, hazard assessment with in vitro studies, and risk range characterization using calculated inhaled doses and dose-response translated to humans from in vitro studies. Here, the methods were utilized to assess workers' risk range of inhalation exposure to nanodiamonds (NDs) during handling and sieving of ND powder. NDs were agglomerated to over 500 nm particles, and mean exposure levels of different work tasks varied from 0.24 to 4.96 µg·m(-3) (0.08 to 0.74 cm(-3)). In vitro-experiments suggested that ND exposure may cause a risk for activation of inflammatory cascade. However, risk range characterization based on in vitro dose-response was not performed because accurate assessment of delivered (settled) dose on the cells was not possible. Comparison of ND exposure with common pollutants revealed that ND exposure was below 5 μg·m(-3), which is one of the proposed exposure limits for diesel particulate matter, and the workers' calculated dose of NDs during the measurement day was 74 ng which corresponded to 0.02% of the modeled daily (24 h) dose of submicrometer urban air particles.

Range-Finding Risk Assessment of Inhalation Exposure to Nanodiamonds in a Laboratory Environment

Directory of Open Access Journals (Sweden)

Antti J. Koivisto

2014-05-01

Full Text Available This study considers fundamental methods in occupational risk assessment of exposure to airborne engineered nanomaterials. We discuss characterization of particle emissions, exposure assessment, hazard assessment with in vitro studies, and risk range characterization using calculated inhaled doses and dose-response translated to humans from in vitro studies. Here, the methods were utilized to assess workers’ risk range of inhalation exposure to nanodiamonds (NDs during handling and sieving of ND powder. NDs were agglomerated to over 500 nm particles, and mean exposure levels of different work tasks varied from 0.24 to 4.96 µg·m−3 (0.08 to 0.74 cm−3. In vitro-experiments suggested that ND exposure may cause a risk for activation of inflammatory cascade. However, risk range characterization based on in vitro dose-response was not performed because accurate assessment of delivered (settled dose on the cells was not possible. Comparison of ND exposure with common pollutants revealed that ND exposure was below 5 μg·m−3, which is one of the proposed exposure limits for diesel particulate matter, and the workers’ calculated dose of NDs during the measurement day was 74 ng which corresponded to 0.02% of the modeled daily (24 h dose of submicrometer urban air particles.

Proteomic analysis of differentiating neuroblastoma cells treated with sub-lethal neurite inhibitory concentrations of diazinon: Identification of novel biomarkers of effect

International Nuclear Information System (INIS)

Harris, W.; Sachana, M.; Flaskos, J.; Hargreaves, A.J.

2009-01-01

In previous work we showed that sub-lethal levels of diazinon inhibited neurite outgrowth in differentiating N2a neuroblastoma cells. Western blotting analysis targeted at proteins involved in axon growth and stress responses, revealed that such exposure led to a reduction in the levels of neurofilament heavy chain, microtubule associated protein 1 B (MAP 1B) and HSP-70. The aim of this study was to apply the approach of 2 dimensional polyacrylamide gel electrophoresis and mass spectrometry to identify novel biomarkers of effect. A number of proteins were found to be up-regulated compared to the control on silver-stained gels. These were classified in to 3 main groups of proteins: cytosolic factors, chaperones and the actin-binding protein cofilin, all of which are involved in cell differentiation, survival or metabolism. The changes observed for cofilin were further confirmed by quantitative Western blotting analysis with anti-actin and anti-cofilin antibodies. Indirect immunofluorescence staining with the same antibodies indicated that the microfilament network was disrupted in diazinon-treated cells. Our data suggest that microfilament organisation is disrupted by diazinon exposure, which may be related to increased cofilin expression.

Sub-Lethal Dose of Shiga toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cythoarquitecture.

Directory of Open Access Journals (Sweden)

Luciana eD’Alessio

2016-02-01

Full Text Available Shiga toxin producing Escherichia coli may damage the central nervous system before or concomitantly to manifested hemolytic uremic syndrome symptoms. The cerebellum is frequently damaged during this syndrome, however the deleterious effects of Shiga toxin 2 has never been integrally reported by ultrastructural, physiological and behavioral means. The aim of this study was to determine the cerebellar compromise after intravenous administration of a sub-lethal dose of Shiga toxin 2 by measuring the cerebellar blood brain barrier permeability, behavioral task of cerebellar functionality (inclined plane test, and ultrastructural analysis (transmission electron microscope. Intravenous administration of vehicle (control group, sub-lethal dose of 0.5 ηg and 1 ηg of Stx2 per mouse were tested for behavioral and ultrastructural studies. A set of three independent experiments were performed for each study (n=6. Blood–Brain Barrier resulted damaged and consequently its permeability was significantly increased. Lower scores obtained in the inclined plane task denoted poor cerebellar functionality in comparison to their controls. The most significant lower score was obtained after 5 days of 1ηg of toxin administration. Transmission electron microscope micrographs from the Stx2-treated groups showed neurons with a progressive neurodegenerative condition in a dose dependent manner. As sub-lethal intravenous Shiga toxin 2 altered the blood brain barrier permeability in the cerebellum the toxin penetrated the cerebellar parenchyma and produced cell damaged with significant functional implications in the test balance.

Drone based measurement system for radiofrequency exposure assessment.

Science.gov (United States)

Joseph, Wout; Aerts, Sam; Vandenbossche, Matthias; Thielens, Arno; Martens, Luc

2016-03-10

For the first time, a method to assess radiofrequency (RF) electromagnetic field (EMF) exposure of the general public in real environments with a true free-space antenna system is presented. Using lightweight electronics and multiple antennas placed on a drone, it is possible to perform exposure measurements. This technique will enable researchers to measure three-dimensional RF-EMF exposure patterns accurately in the future and at locations currently difficult to access. A measurement procedure and appropriate measurement settings have been developed. As an application, outdoor measurements are performed as a function of height up to 60 m for Global System for Mobile Communications (GSM) 900 MHz base station exposure. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Lethal and sublethal measures of chronic copper toxicity in the eastern narrowmouth toad, Gastrophryne carolinensis.

Science.gov (United States)

Flynn, R Wesley; Scott, David E; Kuhne, Wendy; Soteropoulos, Diana; Lance, Stacey L

2015-03-01

Many metals are acutely toxic to aquatic organisms at high concentrations and for some metals, such as copper (Cu), even low-level chronic contamination may be cause for conservation concern. Amphibian susceptibility to Cu has been examined in only a few species, and susceptibility is highly variable. The lethal and sublethal effects were examined of chronic aqueous Cu exposure on embryonic and larval eastern narrowmouth toads, Gastrophryne carolinensis. Copper levels as low as 10 μg Cu/L reduced embryonic and larval survival. Embryonic survivorship varied within- and between-source populations, with embryos derived from uncontaminated-wetland parents having greater survival at lower Cu levels than embryos from parents from a metal-contaminated constructed wetland. At 30 μg/L, embryos from the contaminated site had greater survival. Overall survival from oviposition to metamorphosis was 68.9% at 0 μg/L and 5.4% at 10 μg/L. Similarly, embryos exposed to ≥50 μg/L demonstrated developmental delays in transition from embryo to free-swimming larva. These results demonstrate a negative population-specific response to environmentally relevant levels of Cu. © 2014 SETAC.

Molecular effects of diethanolamine exposure on Calanus finmarchicus (Crustacea: Copepoda)

Energy Technology Data Exchange (ETDEWEB)

Hansen, Bjorn Henrik, E-mail: bjorn.h.hansen@sintef.no [SINTEF Materials and Chemistry, Marine Environmental Technology, Brattorkaia 17B, N-7465 Trondheim (Norway); Altin, Dag [BioTrix, N-7022 Trondheim (Norway); Booth, Andy; Vang, Siv-Hege; Frenzel, Max; Sorheim, Kristin Rist; Brakstad, Odd Gunnar [SINTEF Materials and Chemistry, Marine Environmental Technology, Brattorkaia 17B, N-7465 Trondheim (Norway); Storseth, Trond R. [SINTEF Fisheries and Aquaculture, N-7465 Trondheim (Norway)

2010-08-15

Alkanolamines are surface-active chemicals used in a wide range of industrial, agricultural and pharmaceutical applications and products. Of particular interest is the use of alkanolamines such as diethanolamine (DEA) in the removal of CO{sub 2} from natural gas and for CO{sub 2} capture following fossil fuel combustion. Despite this widespread use, relatively little is known about the ecotoxicological impacts of these compounds. In an attempt to assess the potential effects of alkanolamines in the marine environment, a key species in the North Atlantic, the planktonic copepod Calanus finmarchicus, was studied for molecular effects following sublethal exposure to DEA. DEA-induced alterations in transcriptome and metabolome profiling were assessed using a suppression subtractive hybridization (SSH) gene library method and high resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR), respectively. Effects were observed on transcription of genes reportedly involved in lipid metabolism, antioxidant systems, metal binding, and amino acid and protein catabolism. These effects were accompanied by altered expression of fatty acid derivates, amino acids (threonine, methionine, glutamine, arginine, alanine and leucine) and cholines (choline, phosphocholine and glycerophosphocholine). Together, SSH and HR-MAS NMR offer complementary screening tools for the assessment of molecular responses of C. finmarchicus to DEA and can be used in the study of other chemicals and organisms. Concentration-response and time-response relationships between DEA exposure and single gene transcription were investigated using quantitative PCR. Specific relationships were found between DEA exposure and the transcription of genes involved in protein catabolism (ubiquitin-specific protease-7), metal ion homeostasis (ferritin) and defence against oxidative stress ({gamma}-glutamylcysteine synthase, glutathione synthase and Cu/Zn-superoxide dismutase). At the lowest alkanolamine

Sublethal effects of buprofezin on development and reproduction in the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae).

Science.gov (United States)

Ali, Ehsan; Liao, Xun; Yang, Peng; Mao, Kaikai; Zhang, Xiaolei; Shakeel, Muhammad; Salim, Abdalla M A; Wan, Hu; Li, Jianhong

2017-12-05

In the present study, the effects of sublethal concentrations of buprofezin on life-table traits of S. furcifera were evaluated for two consecutive generations (F0 and F1). Our results exhibited that the fecundity, life span (longevity) and hatchability of the F0 and F1 generations were significantly decreased at LC 30 compared to the control. However, copulation was not significantly affected for the F0 or F1 generations at sublethal concentrations. The female life span was affected negatively at both treatments in F0 and at LC 30 in F1, compared to the control. Furthermore, significant effects of the sublethal concentrations were found on the developmental rate of all instars except the 3 rd instar of F1. However, the pre-adult period, total pre-oviposition period (TPOP) and adult pre-oviposition period (APOP) significantly increased in F1 individuals at LC 30 and LC 10 compared to the control. Our findings revealed that demographic characters (survival rate, intrinsic rate of increase (ri), finite rate of increase (λ), net reproductive rate (R 0 ), and gross reproductive rate (GRR)) of the F1 generation (from F0 parents) significantly decreased compared to the untreated group; however, the generation time (T) increased at LC 10 . Therefore, the results suggested that buprofezin could adversely affect individuals in the successive generation.

Studies on the pathogenesis and survival of different culture forms of Listeria monocytogenes to pulsed UV-light irradiation after exposure to mild-food processing stresses.

Science.gov (United States)

Bradley, Derek; McNeil, Brian; Laffey, John G; Rowan, Neil J

2012-06-01

The effects of mild conventional food-processing conditions on Listeria monocytogenes survival to pulsed UV (PUV) irradiation and virulence-associated characteristics were investigated. Specifically, this study describes the inability of 10 strains representative of 3 different culture forms or morphotypes of L. monocytogenes to adapt to normally lethal levels of PUV-irradiation after exposure to sub-lethal concentrations of salt (7.5% (w/v) NaCl for 1 h), acid (pH 5.5 for 1 h), heating (48 °C for 1 h) or PUV (UV dose 0.08 μJ/cm(2)). Findings showed that the order of increasing sensitivity of L. monocytogenes of non-adapted and stressed morphotypes to low pH (pH 3.5 for 5 h, adjusted with lactic), high salt (17.5% w/v NaCl for 5 h), heating (60 °C for 1 h) and PUV-irradiation (100 pulses at 7.2 J and 12.8 J, equivalent to UV doses of 2.7 and 8.4 μJ/cm(2) respectively) was typical wild-type smooth (S/WT), atypical filamentous rough (FR) and atypical multiple-cell-chain (MCR) variants. Exposure of L. monocytogenes cells to sub-lethal acid, salt or heating conditions resulted in similar or increased susceptibility to PUV treatments. Only prior exposure to mild heat stressing significantly enhanced invasion of Caco-2 cells, whereas subjection of L. monocytogenes cells to combined sub-lethal salt, acid and heating conditions produced the greatest reduction in invasiveness. Implications of these findings are discussed. This constitutes the first study to show that pre-exposure to mild conventional food-processing stresses enhances sensitivity of different culture morphotypes of L. monocytogenes to PUV, which is growing in popularity as an alternative or complementary approach for decontamination in the food environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Critical elements for human health risk assessment of less than lifetime exposures.

Science.gov (United States)

Geraets, Liesbeth; Nijkamp, Monique M; Ter Burg, Wouter

2016-11-01

Less than lifetime exposure has confronted risk assessors as to how to interpret the risks for human health in case a chronic health-based limit is exceeded. Intermittent, fluctuating and peak exposures do not match with the basis of the chronic limit values possibly leading to conservative outcomes. This paper presents guidance on how to deal with human risk assessment of less than lifetime exposure. Important steps to be considered are characterization of the human exposure situation, evaluation whether the human less than lifetime exposure scenario corresponds to a non-chronic internal exposure: toxicokinetic and toxicodynamic considerations, and, finally, re-evaluation of the risk assessment. Critical elements for these steps are the mode of action, Haber's rule, and toxicokinetics (ADME) amongst others. Previous work for the endpoints non-genotoxic carcinogenicity and developmental toxicity is included in the guidance. The guidance provides a way to consider the critical elements, without setting default factors to correct for the less than lifetime exposure in risk assessment. Copyright © 2016 Elsevier Inc. All rights reserved.

Release of nanomaterials from solid nanocomposites and consumer exposure assessment - a forward-looking review

DEFF Research Database (Denmark)

Mackevica, Aiga; Hansen, Steffen Foss

2016-01-01

of the studies report their findings in a format that can be used for exposure assessment under REACH, and most do not include characterization of the released particles. Although inhalation, dermal, and oral exposures can be derived using the guidelines on how to complete consumer exposure assessments under......The European chemical legislation requires manufacturers and importers of chemicals to do consumer exposure assessment when the chemical has certain hazards associated to it (e.g. explosive, carcinogenicity, and hazardous to the aquatic environment), but the question is how this obligation can...... be met in light of the scientific uncertainty and technical challenges related to exposure assessment of nanomaterials. In this paper, we investigate to what extent the information and data in the literature can be used to perform consumer exposure assessment according to the REACH requirements and we...

Exposure assessment in studies on health effects of traffic exhaust

Energy Technology Data Exchange (ETDEWEB)

Setaelae, S. [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J.J.K. [Helsinki Univ. (Finland). Dept. of Public Health

1995-12-31

A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

Exposure assessment in studies on health effects of traffic exhaust

Energy Technology Data Exchange (ETDEWEB)

Setaelae, S [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J J.K. [Helsinki Univ. (Finland). Dept. of Public Health

1996-12-31

A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

Long-term dietary exposure to lead in young European children: Comparing a pan-European approach with a national exposure assessment

DEFF Research Database (Denmark)

Boon, P.E.; Te Biesebeek, J.D.; van Klaveren, J.D.

2012-01-01

Long-term dietary exposures to lead in young children were calculated by combining food consumption data of 11 European countries categorised using harmonised broad food categories with occurrence data on lead from different Member States (pan-European approach). The results of the assessment...... in children living in the Netherlands were compared with a long-term lead intake assessment in the same group using Dutch lead concentration data and linking the consumption and concentration data at the highest possible level of detail. Exposures obtained with the pan-European approach were higher than...... the national exposure calculations. For both assessments cereals contributed most to the exposure. The lower dietary exposure in the national study was due to the use of lower lead concentrations and a more optimal linkage of food consumption and concentration data. When a pan-European approach, using...

A methodology for assessing the impact of mutagens on aquatic ecosystems. Final report

International Nuclear Information System (INIS)

Knezovich, J.P.; Martinelli, R.E.

1995-03-01

Assessments of impacts of hazardous agents (i.e., chemical and physical mutagens) on human health have focused on defining the effects of chronic exposure on individuals, with cancer being the main effect of concern. In contrast, impacts on ecosystems have traditionally been gauged by the assessment of near-term organism mortality, which is clearly not a useful endpoint for assessing the long-term effects of chronic exposures. Impacts on individual organisms that affect the long-term survival of populations are much more important but are also more difficult to define. Therefore, methods that provide accurate measures of sub-lethal effects that are linked to population survival are required so that accurate assessments of environmental damage can be made and remediation efforts, if required, can be initiated. Radioactive substances have entered aquatic environments as a result of research and production activities, intentional disposal, and accidental discharges. At several DOE sites, surface waters and sediments are contaminated with radioactive and mutagenic materials. The accident at the Chernobyl power station in the former Soviet Union (FSU) has resulted in the contamination of biota present in the Kiev Reservoir. This documents presents a methodology which addresses the effects of a direct-acting mutagen (radiation) on aquantic organisms by applying sensitive techniques for assessing damage to genetic material

Acute toxicities and sublethal effects of some conventional insecticides on Trichogramma chilonis (Hymenoptera: Trichogrammatidae).

Science.gov (United States)

Wang, De-Sen; He, Yu-Rong; Guo, Xiang-Ling; Luo, Yong-Li

2012-08-01

The acute toxicity of 10 conventional insecticides to adult of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) was bioassayed by membrane method, and then their sublethal effects on the parasitoid were evaluated in the laboratory. Based on sublethal concentration (LC30) values at 8 h after treatment, we determined that adult T. chilonis were the most susceptible to chlorfenapyr, followed by fipronil, spinosad, avermectins, beta-cypermethrin, and cartap, with lethal concentration (LC)30 values of 0.3133, 0.3269, 1.5408, 3.2961, 6.1469, and 9.021 mg/liter, respectively. The field-recommended concentrations of chlorfluazuron, indoxacarb, Bacillus thuringiensis, and tebufenozide caused Cartap and spinosad also reduced longevity (8 and 7.9 d) and fecundity (110.77 and 117.2) of treated adults, but cartap enhanced the female percentage of F1 offspring (61.6%), resulting a statistical higher R0, r(m), and lambda of treated T. chilonis. In contrast, chlorfluazuron and tebufenozide increased longevity (16.4 and 15.4 d) and fecundity (248 and 256.9) of treated adults but slightly decreased the female percentage of F1 offspring (31.4 and 38.1%). Although chlorfenapyr showed no adverse influence on longevity and fecundity, it remarkably reduced the female percentage of F1 offspring (13.5%), leading to a lower R0, r(m), and lambda of treated T. chilonis. Indoxacarb, B. thuringiensis, and beta-cypermethrin had no obvious sublethal effects on the longevity and fecundity of treated adults. Based on these results, we consider B. thuringienesis, chlorfluazuron, indoxacarb, beta-cypermethrin, and tebufenozide safe to T. chilonis, suggesting that these insecticides are compatible with this parasitoid when being used in the field. However, fipronil, chlorfenapyr, spinosad, and avermectins were very harmful to T. chilonis. Timing of application of these insecticides was critical.

Quantitative Analysis of Aedes albopictus Movement Behavior Following Sublethal Exposure To Prallethrin.

Science.gov (United States)

Dye-Braumuller, Kyndall C; Haynes, Kenneth F; Brown, Grayson C

2017-12-01

The pyrethroid prallethrin, an AI in DUET™ (Clarke Mosquito Control, St. Charles, IL), is widely marketed ultra-low volume (ULV) mosquito adulticide. Volatilized prallethrin is intended to stimulate mosquito flight, increasing its adulticide effectiveness. However, field tests using volatilized prallethrin have not produced significant differences in mosquito trap catches, leading to questions regarding prallethrin's behavioral impact efficacy. Thus, we conducted laboratory tests of prallethrin's effect on flight behavior of adult female Asian tiger mosquitoes, Aedes albopictus. Mosquitoes were divided into 3 groups: untreated control, exposed to volatilized prallethrin, and exposed to a liquid spray calibrated to simulate a ULV application at label rates. After exposure, mosquito behavior in an airstream of 0.5 m/sec was recorded and analyzed using motion-tracking software. No significant differences in flight behavior were found between the control and treated mosquitoes exposed to volatilized prallethrin. The ULV-sprayed mosquitoes exhibited a significant increase in the number of flight events, the turning frequency, overall movement speed, and flight speed compared to the control-a significant difference in locomotor stimulation response that would increase exposure to a ULV spray cloud. However, our results showed that volatilization alone was insufficient to increase ULV efficacy in the field and suggested that incorporating a more volatile flight stimulant into ULV adulticides would provide a measurable improvement in mosquito control.

The SOS response increases bacterial fitness, but not evolvability, under a sublethal dose of antibiotic.

Science.gov (United States)

Torres-Barceló, Clara; Kojadinovic, Mila; Moxon, Richard; MacLean, R Craig

2015-10-07

Exposure to antibiotics induces the expression of mutagenic bacterial stress-response pathways, but the evolutionary benefits of these responses remain unclear. One possibility is that stress-response pathways provide a short-term advantage by protecting bacteria against the toxic effects of antibiotics. Second, it is possible that stress-induced mutagenesis provides a long-term advantage by accelerating the evolution of resistance. Here, we directly measure the contribution of the Pseudomonas aeruginosa SOS pathway to bacterial fitness and evolvability in the presence of sublethal doses of ciprofloxacin. Using short-term competition experiments, we demonstrate that the SOS pathway increases competitive fitness in the presence of ciprofloxacin. Continued exposure to ciprofloxacin results in the rapid evolution of increased fitness and antibiotic resistance, but we find no evidence that SOS-induced mutagenesis accelerates the rate of adaptation to ciprofloxacin during a 200 generation selection experiment. Intriguingly, we find that the expression of the SOS pathway decreases during adaptation to ciprofloxacin, and this helps to explain why this pathway does not increase long-term evolvability. Furthermore, we argue that the SOS pathway fails to accelerate adaptation to ciprofloxacin because the modest increase in the mutation rate associated with SOS mutagenesis is offset by a decrease in the effective strength of selection for increased resistance at a population level. Our findings suggest that the primary evolutionary benefit of the SOS response is to increase bacterial competitive ability, and that stress-induced mutagenesis is an unwanted side effect, and not a selected attribute, of this pathway. © 2015 The Authors.

Putative midkine family protein up-regulation in Patella caerulea (Mollusca, Gastropoda) exposed to sublethal concentrations of cadmium

International Nuclear Information System (INIS)

Vanucci, Silvana; Minerdi, Daniela; Kadomatsu, Kenji; Mengoni, Alessio; Bazzicalupo, Marco

2005-01-01

A cDNA sequence of a putative midkine (MK) family protein was identified and characterised in the mollusc Patella caerulea. The midkine family consists of two members, midkine and pleiotrophin (PTN), and it is one of the recently discovered cytokines. Our results show that this putative midkine protein is up-regulated in specimens of P. caerulea exposed to sublethal cadmium concentrations (i.e. 0.5 and 1 mg l -1 Cd) over a 10-day exposure period. Semiquantitative RT-PCR and quantitative Real time RT-PCR estimations indicate elevated expression of midkine mRNA in exposed specimens compared to controls. Moreover, RT-PCR Real time values were higher in the viscera (here defined as the part of the soft tissue including digestive gland plus gills) than in the foot (i.e. foot plus head plus heart) of the limpets. At present, information on the functional signalling significance of the midkine family proteins suggests that the up-regulation of P. caerulea putative midkine family protein is a distress signal likely with informative value on health status of the organism and with potential prognostic capability

Distinguishing nanomaterial particles from background airborne particulate matter for quantitative exposure assessment

Science.gov (United States)

Ono-Ogasawara, Mariko; Serita, Fumio; Takaya, Mitsutoshi

2009-10-01

As the production of engineered nanomaterials quantitatively expands, the chance that workers involved in the manufacturing process will be exposed to nanoparticles also increases. A risk management system is needed for workplaces in the nanomaterial industry based on the precautionary principle. One of the problems in the risk management system is difficulty of exposure assessment. In this article, examples of exposure assessment in nanomaterial industries are reviewed with a focus on distinguishing engineered nanomaterial particles from background nanoparticles in workplace atmosphere. An approach by JNIOSH (Japan National Institute of Occupational Safety and Health) to quantitatively measure exposure to carbonaceous nanomaterials is also introduced. In addition to real-time measurements and qualitative analysis by electron microscopy, quantitative chemical analysis is necessary for quantitatively assessing exposure to nanomaterials. Chemical analysis is suitable for quantitative exposure measurement especially at facilities with high levels of background NPs.

Harmonisation of food categorisation systems for dietary exposure assessments among European children

DEFF Research Database (Denmark)

De Neve, Melissa; Sioen, Isabelle; Boon, Polly

2010-01-01

Within the European project called EXPOCHI (Individual Food Consumption Data and Exposure Assessment Studies for Children), 14 different European individual food consumption databases of children were used to conduct harmonised dietary exposure assessments for lead, chromium, selenium and food...... colours. For this, two food categorisation systems were developed to classify the food consumption data in such a way that these could be linked to occurrence data of the considered compounds. One system served for the exposure calculations of lead, chromium and selenium. The second system was developed...... for the exposure assessment of food colours. The food categories defined for the lead, chromium and selenium exposure calculations were used as a basis for the food colour categorisation, with adaptations to optimise the linkage with the food colour occurrence data. With this work, an initial impetus was given...

Lethal and sublethal effects of four essential oils on the egg parasitoids Trissolcus basalis.

Science.gov (United States)

Werdin González, Jorge Omar; Laumann, Raúl Alberto; da Silveira, Samantha; Moraes, Maria Carolina Blassioli; Borges, Miguel; Ferrero, Adriana Alicia

2013-07-01

The essential oils from leaves of Schinus molle var. areira, Aloysia citriodora, Origanum vulgare and Thymus vulgaris have showed potential as phytoinsecticides against the green stink bug, Nezara viridula. In this work were evaluated their toxicological and behavioral effects on the parasitoid Trissolcus basalis, a biological control agent of this pest insect. Essential oils were obtained via hydrodestillation from fresh leaves. Insecticide activity in T. basalis females was evaluated in direct contact and fumigation bioassays. Behavioral effects were evaluated in olfactometer bioassays. To evaluate the residual toxicity, females of the parasitoids were exposed to oil residues; in these insects, the sublethal effects were evaluated (potential parasitism and survivorship of immature stages). The essential oils from O. vulgare and T. vulgaris proved to be highly selective when used as fumigant and did not change parasitoid behavior. After one week, the residues of these oils were harmless and did not show sublethal effects against T. basalis. According with these results, essential oils have potential applications for the integrated management of N. viridula. Published by Elsevier Ltd.

Risk assessment for heart disease and workplace ETS exposure among nonsmokers.

OpenAIRE

Steenland, K

1999-01-01

In 1994 the U.S. Occupational Health and Safety Administration (OSHA) published a study of risk assessment for heart disease and lung cancer resulting from workplace exposure to environmental tobacco smoke (ETS) among nonsmokers. This assessment is currently being revised. The present article considers different possible approaches to a risk assessment for heart disease among nonsmokers resulting from workplace ETS exposure, reviews the approach taken by OSHA in 1994, and suggests some modifi...

Improving the relevance and efficiency of human exposure assessments within the process of regulatory risk assessment.

Science.gov (United States)

Money, Chris

2018-01-24

The process for undertaking exposure assessments varies dependent on its purpose. But for exposure assessments to be relevant and accurate, they are reliant on access to reliable information on key exposure determinants. Acquiring such information is seldom straightforward and can take significant time and resources. This articles examines how the application of tiered and targeted approaches to information acquisition, within the context of European human health risk assessments, can not only lead to improvements in the efficiency and effectiveness of the process but also in the confidence of stakeholders in its outputs. The article explores how the benefits might be further improved through the coordination of such activities, as well as those areas that represent barriers to wider international harmonisation.

Primary blast survival and injury risk assessment for repeated blast exposures.

Science.gov (United States)

Panzer, Matthew B; Bass, Cameron R Dale; Rafaels, Karin A; Shridharani, Jay; Capehart, Bruce P

2012-02-01

The widespread use of explosives by modern insurgents and terrorists has increased the potential frequency of blast exposure in soldiers and civilians. This growing threat highlights the importance of understanding and evaluating blast injury risk and the increase of injury risk from exposure to repeated blast effects. Data from more than 3,250 large animal experiments were collected from studies focusing on the effects of blast exposure. The current study uses 2,349 experiments from the data collection for analysis of the primary blast injury and survival risk for both long- and short-duration blasts, including the effects from repeated exposures. A piecewise linear logistic regression was performed on the data to develop survival and injury risk assessment curves. New injury risk assessment curves uniting long- and short-duration blasts were developed for incident and reflected pressure measures and were used to evaluate the risk of injury based on blast over pressure, positive-phase duration, and the number of repeated exposures. The risk assessments were derived for three levels of injury severity: nonauditory, pulmonary, and fatality. The analysis showed a marked initial decrease in injury tolerance with each subsequent blast exposure. This effect decreases with increasing number of blast exposures. The new injury risk functions showed good agreement with the existing experimental data and provided a simplified model for primary blast injury risk. This model can be used to predict blast injury or fatality risk for single exposure and repeated exposure cases and has application in modern combat scenarios or in setting occupational health limits. .Copyright © 2012 by Lippincott Williams & Wilkins

Children's exposure assessment of radiofrequency fields: Comparison between spot and personal measurements.

Science.gov (United States)

Gallastegi, Mara; Huss, Anke; Santa-Marina, Loreto; Aurrekoetxea, Juan J; Guxens, Mònica; Birks, Laura Ellen; Ibarluzea, Jesús; Guerra, David; Röösli, Martin; Jiménez-Zabala, Ana

2018-05-24

Radiofrequency (RF) fields are widely used and, while it is still unknown whether children are more vulnerable to this type of exposure, it is essential to explore their level of exposure in order to conduct adequate epidemiological studies. Personal measurements provide individualized information, but they are costly in terms of time and resources, especially in large epidemiological studies. Other approaches, such as estimation of time-weighted averages (TWAs) based on spot measurements could simplify the work. The aims of this study were to assess RF exposure in the Spanish INMA birth cohort by spot measurements and by personal measurements in the settings where children tend to spend most of their time, i.e., homes, schools and parks; to identify the settings and sources that contribute most to that exposure; and to explore if exposure assessment based on spot measurements is a valid proxy for personal exposure. When children were 8 years old, spot measurements were conducted in the principal settings of 104 participants: homes (104), schools and their playgrounds (26) and parks (79). At the same time, personal measurements were taken for a subsample of 50 children during 3 days. Exposure assessment based on personal and on spot measurements were compared both in terms of mean exposures and in exposure-dependent categories by means of Bland-Altman plots, Cohen's kappa and McNemar test. Median exposure levels ranged from 29.73 (in children's bedrooms) to 200.10 μW/m 2 (in school playgrounds) for spot measurements and were higher outdoors than indoors. Median personal exposure was 52.13 μW/m 2 and median levels of assessments based on spot measurements ranged from 25.46 to 123.21 μW/m 2 . Based on spot measurements, the sources that contributed most to the exposure were FM radio, mobile phone downlink and Digital Video Broadcasting-Terrestrial, while indoor and personal sources contributed very little (altogether spot measurements, with the latter

Aggregate Exposure and Cumulative Risk Assessment--Integrating Occupational and Non-occupational Risk Factors.

Science.gov (United States)

Lentz, T J; Dotson, G S; Williams, P R D; Maier, A; Gadagbui, B; Pandalai, S P; Lamba, A; Hearl, F; Mumtaz, M

2015-01-01

Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational.

Chemical Exposure Assessment Program at Los Alamos National Laboratory: A risk based approach

International Nuclear Information System (INIS)

Stephenson, D.J.

1996-01-01

The University of California Contract And DOE Order 5480.10 require that Los Alamos National Laboratory (LANL) perform health hazard assessments/inventories of all employee workplaces. In response to this LANL has developed the Chemical Exposure Assessment Program. This program provides a systematic risk-based approach to anticipation, recognition, evaluation and control of chemical workplace exposures. Program implementation focuses resources on exposures with the highest risks for causing adverse health effects. Implementation guidance includes procedures for basic characterization, qualitative risk assessment, quantitative validation, and recommendations and reevaluation. Each component of the program is described. It is shown how a systematic method of assessment improves documentation, retrieval, and use of generated exposure information

Oxidative stress and histopathologic biomarkers of exposure to bisphenol-A in the freshwater fish, Ctenopharyngodon idella

Directory of Open Access Journals (Sweden)

Mehwish Faheem

2018-02-01

Full Text Available ABSTRACT Bisphenol-A (BPA belongs to the family of endocrine disrupting chemicals (EDCs and it is used in the production of polycarbonate plastic and epoxy resins. The reproductive toxicity of BPA is well documented but it also exerts its toxic effects through multiple pathways especially by inducing a state of oxidative stress and causing damage to the vital organs. In the present study, histopathologic and oxidative damage caused by BPA in liver and kidneys of fresh water cyprinid, Ctenopharyngodon idella was evaluated. LC50 of BPA for Ctenopharyngodon idella was determined by probit regression analysis. Fish were exposed to a sublethal concentration of BPA i.e. 3.2 ppm (1/2 LC50 for 14 days. Histologic studies revealed that BPA caused degenerative changes in liver and kidneys and exposure of sublethal concentration of BPA caused oxidative damage in both organs. Lipid peroxidation significantly increased in liver and kidneys of treated group. Catalase activity and reduced glutathione content significantly decreased in the group exposed to BPA compared to control and glutathione-S-transferase activity increased significantly in both organs exposed to the sublethal concentration of BPA. From this study it is concluded that BPA caused toxic effects in fish species by changing oxidative balance and damaging the vital organs.

Assessment of genetic risk for human exposure to radiation

International Nuclear Information System (INIS)

Sevcenko, V.A.; Rubanovic, A.V.

2002-01-01

Full text: The methodology of assessing the genetic risk of radiation exposure is based on the concept of 'hitting the target' in development of which N.V. Timofeeff-Ressovsky has played and important role. To predict genetic risk posed by irradiation, the U N Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has worked out direct and indirect methods of assessment, extrapolation, integral and palpitation criteria of risk analysis that together permit calculating the risk from human exposure on the basis of data obtained for mice. Based on the reports of UNSCEAR for the period from 1958 to 2001 the paper presents a retrospective analysis of the use of direct methods and the doubling dose method for quantitative determination of the genetic risk of human exposure expressed as different hereditary diseases. As early as 1962 UNSCEAR estimated the doubling dose (a dose causing as many mutations as those occurring spontaneously during one generation) at 1 Gy for cases of exposure to ionizing radiations with low LET at a low dose rate and this value was confirmed in the next UNSCEAR reports up to now. For cases of acute irradiation the doubling dose was estimated at 0,3-0,4 Gy for the period under review. The paper considers the evolution of the concepts of human natural hereditary variability which is a basis for assessing the risk of exposure by the doubling dose method. The level of human natural genetic variability per 1 000 000 newborns is estimated at 738 000 hereditary diseases including mendelian, chromosomal and multifactorial ones. The greatest difficulties in assessing the doubling dose value were found to occur in the case of multifactorial diseases the pheno typical expression of which depends on mutational events in polygenic systems and on numerous environmental factors. The introduction in calculations of the potential recoverability correction factor (RPCF) made it possible to assess the genetic risk taking into account this class of

An introduction to the indirect exposure assessment approach: modeling human exposure using microenvironmental measurements and the recent National Human Activity Pattern Survey.

Science.gov (United States)

Klepeis, N E

1999-01-01

Indirect exposure approaches offer a feasible and accurate method for estimating population exposures to indoor pollutants, including environmental tobacco smoke (ETS). In an effort to make the indirect exposure assessment approach more accessible to people in the health and risk assessment fields, this paper provides examples using real data from (italic>a(/italic>) a week-long personal carbon monoxide monitoring survey conducted by the author; and (italic>b(/italic>) the 1992 to 1994 National Human Activity Pattern Survey (NHAPS) for the United States. The indirect approach uses measurements of exposures in specific microenvironments (e.g., homes, bars, offices), validated microenvironmental models (based on the mass balance equation), and human activity pattern data obtained from questionnaires to predict frequency distributions of exposure for entire populations. This approach requires fewer resources than the direct approach to exposure assessment, for which the distribution of monitors to a representative sample of a given population is necessary. In the indirect exposure assessment approach, average microenvironmental concentrations are multiplied by the total time spent in each microenvironment to give total integrated exposure. By assuming that the concentrations encountered in each of 10 location categories are the same for different members of the U.S. population (i.e., the NHAPS respondents), the hypothetical contribution that ETS makes to the average 24-hr respirable suspended particle exposure for Americans working their main job is calculated in this paper to be 18 microg/m3. This article is an illustrative review and does not contain an actual exposure assessment or model validation. Images Figure 3 Figure 4 PMID:10350522

Validating the use of embryonic fish otoliths as recorders of sublethal exposure to copper in estuarine sediments

International Nuclear Information System (INIS)

Barbee, Nicole C.; Greig, Alan; Swearer, Stephen E.

2013-01-01

In this study we explore the use of fish otoliths (‘earbones’) as a tool for detecting exposure to heavy metals in sediments. Because otoliths are metabolically inert and incorporate chemical impurities during growth, they can potentially provide a more permanent record of pollutant exposure history in aquatic environments than soft tissues. To validate this technique we cultured embryos of a native Australian fish, the common Galaxias (Galaxias maculatus), in the laboratory on sediments spiked with copper in a concentration gradient. Our aims were to test whether exposure to copper contaminated sediments is recorded in the otoliths of embryos and determine over what range in concentrations we can detect differences in exposure. We found elevated copper levels in otoliths of embryos exposed to high copper concentrations in sediments, suggesting that otoliths can be used as a tool to track a history of exposure to elevated copper levels in the environment. -- Highlights: •Our aim was to determine if exposure to Cu is recorded in embryonic fish otoliths. •Fish eggs were cultured on Cu-spiked sediments in a gradient of concentrations. •Fish do uptake and incorporate Cu into their otoliths during development. •High sediment Cu concentrations resulted in high otolith Cu concentrations. •With further validation, otoliths could be used to track a history of Cu exposure. -- We use sediments spiked with Cu to examine the uptake of heavy metals into embryonic fish otoliths as a novel tool for tracking pollution exposure history

Radioprotective effects in mice by a single dose of subcutaneous administration of cobaltous chloride post γ-rays irradiation with a sublethal dose

International Nuclear Information System (INIS)

Izumo, Yoshiro; Ogata, Hiromitsu

1993-01-01

Radioprotective effects were investigated in mice which received subcutaneously a single dose of each inorganic metal: Co, Cu, Rb, Sr, Mo and W 24 hours post irradiation of 60 Co γ-rays with a sublethal dose. The effects were observed in mice injected with Co at an optimum dosage of 20 mg/kg·body weight. Then to elucidate mechanisms of the effects, mice were injected with Co containing the radioactive tracer ( 60 Co) following the radiation exposure, measured elimination of the radioactivity for 7 days, then sacrificed and divided to some tissues and organs. The radioactivity in whole body during this period resulted in a markedly higher retention than that for mice injected with [ 60 Co] alone, as well as liver in the organs. These higher retentions appeared to be related to the radioprotective effects. (author)

Environmental exposure assessment framework for nanoparticles in solid waste

Science.gov (United States)

Boldrin, Alessio; Hansen, Steffen Foss; Baun, Anders; Hartmann, Nanna Isabella Bloch; Astrup, Thomas Fruergaard

2014-06-01

Information related to the potential environmental exposure of engineered nanomaterials (ENMs) in the solid waste management phase is extremely scarce. In this paper, we define nanowaste as separately collected or collectable waste materials which are or contain ENMs, and we present a five-step framework for the systematic assessment of ENM exposure during nanowaste management. The framework includes deriving EOL nanoproducts and evaluating the physicochemical properties of the nanostructure, matrix properties and nanowaste treatment processes as well as transformation processes and environment releases, eventually leading to a final assessment of potential ENM exposure. The proposed framework was applied to three selected nanoproducts: nanosilver polyester textile, nanoTiO2 sunscreen lotion and carbon nanotube tennis racquets. We found that the potential global environmental exposure of ENMs associated with these three products was an estimated 0.5-143 Mg/year, which can also be characterised qualitatively as medium, medium, low, respectively. Specific challenges remain and should be subject to further research: (1) analytical techniques for the characterisation of nanowaste and its transformation during waste treatment processes, (2) mechanisms for the release of ENMs, (3) the quantification of nanowaste amounts at the regional scale, (4) a definition of acceptable limit values for exposure to ENMs from nanowaste and (5) the reporting of nanowaste generation data.

Development of a method for personal, spatiotemporal exposure assessment.

Science.gov (United States)

Adams, Colby; Riggs, Philip; Volckens, John

2009-07-01

This work describes the development and evaluation of a high resolution, space and time-referenced sampling method for personal exposure assessment to airborne particulate matter (PM). This method integrates continuous measures of personal PM levels with the corresponding location-activity (i.e. work/school, home, transit) of the subject. Monitoring equipment include a small, portable global positioning system (GPS) receiver, a miniature aerosol nephelometer, and an ambient temperature monitor to estimate the location, time, and magnitude of personal exposure to particulate matter air pollution. Precision and accuracy of each component, as well as the integrated method performance were tested in a combination of laboratory and field tests. Spatial data was apportioned into pre-determined location-activity categories (i.e. work/school, home, transit) with a simple, temporospatially-based algorithm. The apportioning algorithm was extremely effective with an overall accuracy of 99.6%. This method allows examination of an individual's estimated exposure through space and time, which may provide new insights into exposure-activity relationships not possible with traditional exposure assessment techniques (i.e., time-integrated, filter-based measurements). Furthermore, the method is applicable to any contaminant or stressor that can be measured on an individual with a direct-reading sensor.

Neonicotinoids and bees: The case of the European regulatory risk assessment.

Science.gov (United States)

Auteri, Domenica; Arena, Maria; Barmaz, Stefania; Ippolito, Alessio; Linguadoca, Alberto; Molnar, Tunde; Sharp, Rachel; Szentes, Csaba; Vagenende, Benedicte; Verani, Alessia

2017-02-01

Neonicotinoid insecticides are systemic pesticides authorised in Europe since 1991. From their introduction on the market, they have received significant attention from the scientific community, particularly regarding the assessment of lethal and sublethal effects on bees. The availability of scientific evidence alongside some concerns raised on the bee health led to the development of more articulate risk assessment methodologies for pesticides. To support the European Commission in its decision-making process, since 2012 EFSA has been requested to evaluate the risk to bees posed by the exposure to neonicotinoids. The outcome of the EFSA evaluations has been used by risk managers to revise the approval conditions of the substances clothianidin, imidacloprid and thiamethoxam and to impose severe restrictions on their use. Meanwhile, a number of new studies have been carried out. EFSA is evaluating these data in order to further support the decision-making process with updated scientific assessments. Copyright © 2016 Elsevier B.V. All rights reserved.

Sublethal pesticide doses negatively affect survival and the cellular responses in American foulbrood-infected honeybee larvae

Science.gov (United States)

López, Javier Hernández; Krainer, Sophie; Engert, Antonia; Schuehly, Wolfgang; Riessberger-Gallé, Ulrike; Crailsheim, Karl

2017-02-01

Disclosing interactions between pesticides and bee infections is of most interest to understand challenges that pollinators are facing and to which extent bee health is compromised. Here, we address the individual and combined effect that three different pesticides (dimethoate, clothianidin and fluvalinate) and an American foulbrood (AFB) infection have on mortality and the cellular immune response of honeybee larvae. We demonstrate for the first time a synergistic interaction when larvae are exposed to sublethal doses of dimethoate or clothianidin in combination with Paenibacillus larvae, the causative agent of AFB. A significantly higher mortality than the expected sum of the effects of each individual stressor was observed in co-exposed larvae, which was in parallel with a drastic reduction of the total and differential hemocyte counts. Our results underline that characterizing the cellular response of larvae to individual and combined stressors allows unmasking previously undetected sublethal effects of pesticides in colony health.

Task-based dermal exposure models for regulatory risk assessment.

Science.gov (United States)

Warren, Nicholas D; Marquart, Hans; Christopher, Yvette; Laitinen, Juha; VAN Hemmen, Joop J

2006-07-01

The regulatory risk assessment of chemicals requires the estimation of occupational dermal exposure. Until recently, the models used were either based on limited data or were specific to a particular class of chemical or application. The EU project RISKOFDERM has gathered a considerable number of new measurements of dermal exposure together with detailed contextual information. This article describes the development of a set of generic task-based models capable of predicting potential dermal exposure to both solids and liquids in a wide range of situations. To facilitate modelling of the wide variety of dermal exposure situations six separate models were made for groupings of exposure scenarios called Dermal Exposure Operation units (DEO units). These task-based groupings cluster exposure scenarios with regard to the expected routes of dermal exposure and the expected influence of exposure determinants. Within these groupings linear mixed effect models were used to estimate the influence of various exposure determinants and to estimate components of variance. The models predict median potential dermal exposure rates for the hands and the rest of the body from the values of relevant exposure determinants. These rates are expressed as mg or microl product per minute. Using these median potential dermal exposure rates and an accompanying geometric standard deviation allows a range of exposure percentiles to be calculated.

Optimizing cost-efficiency in mean exposure assessment--cost functions reconsidered.

Science.gov (United States)

Mathiassen, Svend Erik; Bolin, Kristian

2011-05-21

Reliable exposure data is a vital concern in medical epidemiology and intervention studies. The present study addresses the needs of the medical researcher to spend monetary resources devoted to exposure assessment with an optimal cost-efficiency, i.e. obtain the best possible statistical performance at a specified budget. A few previous studies have suggested mathematical optimization procedures based on very simple cost models; this study extends the methodology to cover even non-linear cost scenarios. Statistical performance, i.e. efficiency, was assessed in terms of the precision of an exposure mean value, as determined in a hierarchical, nested measurement model with three stages. Total costs were assessed using a corresponding three-stage cost model, allowing costs at each stage to vary non-linearly with the number of measurements according to a power function. Using these models, procedures for identifying the optimally cost-efficient allocation of measurements under a constrained budget were developed, and applied on 225 scenarios combining different sizes of unit costs, cost function exponents, and exposure variance components. Explicit mathematical rules for identifying optimal allocation could be developed when cost functions were linear, while non-linear cost functions implied that parts of or the entire optimization procedure had to be carried out using numerical methods.For many of the 225 scenarios, the optimal strategy consisted in measuring on only one occasion from each of as many subjects as allowed by the budget. Significant deviations from this principle occurred if costs for recruiting subjects were large compared to costs for setting up measurement occasions, and, at the same time, the between-subjects to within-subject variance ratio was small. In these cases, non-linearities had a profound influence on the optimal allocation and on the eventual size of the exposure data set. The analysis procedures developed in the present study can be used

Risk assessment of fluoride exposure in drinking water of Tunisia.

Science.gov (United States)

Guissouma, Wiem; Hakami, Othman; Al-Rajab, Abdul Jabbar; Tarhouni, Jamila

2017-06-01

The presence of fluoride in drinking water is known to reduce dental cavities among consumers, but an excessive intake of this anion might leads to dental and skeletal fluorosis. This study reports a complete survey of the fluoridated tap water taken from 100 water consumption points in Tunisia. The fluoride concentrations in tap water were between 0 and 2.4 mg L -1 . Risk assessment of Fluoride exposure was assessed depending on the age of consumers using a four-step method: hazard identification, toxicity reference values selection (TRVs), daily exposure assessment, and risk characterization. Our findings suggest that approximately 75% of the Tunisian population is at risk for dental decay, 25% have a potential dental fluorosis risk, and 20% might have a skeletal fluorosis risk according to the limits of fluoride in drinking water recommended by WHO. More investigations are recommended to assess the exposure risk of fluoride in other sources of drinking water such as bottled water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elaboration of a concept for the cumulative environmental exposure assessment of biocides

Energy Technology Data Exchange (ETDEWEB)

Gross, Rita; Bunke, Dirk; Moch, Katja [Oeko-Institut e.V. - Institut fuer Angewandte Oekologie e.V., Freiburg im Breisgau (Germany); Gartiser, Stefan [Hydrotox GmbH, Freiburg im Breisgau (Germany)

2011-12-15

Article 10(1) of the EU Biocidal Products Directive 98/8/EC (BPD) requires that for the inclusion of an active substance in Annex I, Annex IA or IB, cumulation effects from the use of biocidal products containing the same active substance shall be taken into account, where relevant. The study proves the feasibility of a technical realisation of Article 10(1) of the BPD and elaborates a first concept for the cumulative environmental exposure assessment of biocides. Existing requirements concerning cumulative assessments in other regulatory frameworks have been evaluated and their applicability for biocides has been examined. Technical terms and definitions used in this context were documented with the aim to harmonise terminology with other frameworks and to set up a precise definition within the BPD. Furthermore, application conditions of biocidal products have been analysed to find out for which cumulative exposure assessments may be relevant. Different parameters were identified which might serve as indicators for the relevance of cumulative exposure assessments. These indicators were then integrated in a flow chart by means of which the relevance of cumulative exposure assessments can be checked. Finally, proposals for the technical performance of cumulative exposure assessments within the Review Programme have been elaborated with the aim to bring the results of the project into the upcoming development and harmonization processes on EU level. (orig.)

Fear and loathing in the benthos: Responses of aquatic insect larvae to the pesticide imidacloprid in the presence of chemical signals of predation risk.

Science.gov (United States)

Pestana, João L T; Loureiro, Susana; Baird, Donald J; Soares, Amadeu M V M

2009-06-28

The influence of interactions between pesticide exposure and perceived predation risk on the lethal and sub-lethal responses of two aquatic insects was investigated using the pesticide imidacloprid, and a combination of predator-release kairomones from trout and alarm substances from conspecifics. Laboratory experiments examined feeding and respiration rates of the caddisfly Sericostoma vittatum as well as the growth, emergence and respiration rates of the midge Chironomus riparius, exposed to sub-lethal concentrations of imidacloprid. The effects of the two stressors on burrowing behaviour of both species were also assessed. The results show significant effects of environmentally relevant concentrations of imidacloprid on all endpoints studied. Perceived predation risk also elicited sub-lethal effects in C. riparius and S. vittatum, the latter species being less responsive to predation cues. The effects of simultaneous exposure to both types of stressors were assessed using two different approaches: analysis of variance and conceptual models [concentration addition (CA) and independent action (IA)] normally used for the evaluation of contaminant mixture exposure. Both statistical approaches showed no significant interactions on responses in simultaneous exposures in the majority of parameters assessed with only a signification deviation from the reference CA and IA models being found for C. riparius respiration data contrary to the ANOVA results. Exposure to imidacloprid also compromised antipredator behavioural responses of both insect species, with potential negative consequences in terms of mortality from predation in the field. The results obtained demonstrate that natural and anthropogenic stressors can be treated within the same framework providing compatible data for modelling. For an improved interpretation of ecological effects it will be important to expand the mechanistic study of effects of combined exposure to pesticides and perceived predation risk

Copresence of tet(K) and tet(M) in Livestock-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 398 Is Associated with Increased Fitness during Exposure to Sublethal Concentrations of Tetracycline

DEFF Research Database (Denmark)

Larsen, Jesper; Clasen, Julie; Hansen, Julie Elvekjær

2016-01-01

The tetracycline resistance gene tet(K) was shown to be integrated within the predominant staphylococcal cassette chromosome mec (SCCmec) element of Danish livestock-associated methicillin-resistant Staphylococcus aureus CC398 (LA-MRSA CC398). These LA-MRSA CC398 isolates already possessed tet(M)......(M), but the acquisition of tet(K) significantly improved their fitness at sublethal concentrations of tetracycline. Because tet(K) is genetically linked to SCCmec, the use of tetracycline in food animals may have contributed to the successful spread of LA-MRSA CC398....

Sublethal Effects in Pest Management: A Surrogate Species Perspective on Fruit Fly Control

Directory of Open Access Journals (Sweden)

John E. Banks

2017-07-01

Full Text Available Tephritid fruit flies are economically important orchard pests globally. While much effort has focused on controlling individual species with a combination of pesticides and biological control, less attention has been paid to managing assemblages of species. Although several tephritid species may co-occur in orchards/cultivated areas, especially in mixed-cropping schemes, their responses to pesticides may be highly variable. Furthermore, predictive efforts about toxicant effects are generally based on acute toxicity, with little or no regard to long-term population effects. Using a simple matrix model parameterized with life history data, we quantified the responses of several tephritid species to the sublethal effects of a toxicant acting on fecundity. Using a critical threshold to determine levels of fecundity reduction below which species are driven to local extinction, we determined that threshold levels vary widely for the three tephritid species. In particular, Bactrocera dorsalis was the most robust of the three species, followed by Ceratitis capitata, and then B. cucurbitae, suggesting individual species responses should be taken into account when planning for area-wide pest control. The rank-order of susceptibility contrasts with results from several field/lab studies testing the same species, suggesting that considering a combination of life history traits and individual species susceptibility is necessary for understanding population responses of species assemblages to toxicant exposure.

A Chemical Activity Approach to Exposure and Risk Assessment of Chemicals

DEFF Research Database (Denmark)

Gobas, Frank A. P. C.; Mayer, Philipp; Parkerton, Thomas F.

2018-01-01

activity approach, its strengths and limitations, and provides examples of how this concept may be applied to the management of single chemicals and chemical mixtures. The examples demonstrate that the chemical activity approach provides a useful framework for 1) compiling and evaluating exposure......To support the goals articulated in the vision for exposure and risk assessment in the twenty-first century, we highlight the application of a thermodynamic chemical activity approach for the exposure and risk assessment of chemicals in the environment. The present article describes the chemical...... assessment. The article further illustrates that the chemical activity approach can support an adaptive management strategy for environmental stewardship of chemicals where “safe” chemical activities are established based on toxicological studies and presented as guidelines for environmental quality...

Does cypermethrin affect enzyme activity, respiration rate and walking behavior of the maize weevil (Sitophilus zeamais)?

Institute of Scientific and Technical Information of China (English)

Ronnie Von Santos Veloso; Eliseu José G.Pereira; Raul Narciso C.Guedes; Maria Goreti A.Oliveira

2013-01-01

Insecticides cause a range of sub-lethal effects on targeted insects,which are frequently detrimental to them.However,targeted insects are able to cope with insecticides within sub-lethal ranges,which vary with their susceptibility.Here we assessed the response of three strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera:Curculionidae) to sub-lethal exposure to the pyrethoid insecticide cypermethrin.We expected enzyme induction associated with cypermethrin resistance since it would aid the resistant insects in surviving such exposure.Lower respiration rate and lower activity were also expected in insecticide-resistant insects since these traits are also likely to favor survivorship under insecticide exposure.Curiously though,cypermethrin did not affect activity of digestive and energy metabolism enzymes,and even reduced the activity of some enzymes (particularly for cellulase and cysteine-proteinase activity in this case).There was strain variation in response,which may be (partially) related to insecticide resistance in some strains.Sub-lethal exposure to cypermethrin depressed proteolytic and mainly cellulolytic activity in the exposed insects,which is likely to impair their fitness.However,such exposure did not affect respiration rate and walking behavior of the insects (except for the susceptible strain where walking activity was reduced).Walking activity varies with strain and may minimize insecticide exposure,which should be a concern,particularly if associated with (physiological) insecticide resistance.

Using ecosystem modelling techniques in exposure assessments of radionuclides - an overview

International Nuclear Information System (INIS)

Kumblad, L.

2005-01-01

The risk to humans from potential releases from nuclear facilities is evaluated in safety assessments. Essential components of these assessments are exposure models, which estimate the transport of radionuclides in the environment, the uptake in biota, and transfer to humans. Recently, there has been a growing concern for radiological protection of the whole environment, not only humans, and a first attempt has been to employ model approaches based on stylized environments and transfer functions to biota based exclusively on bioconcentration factors (BCF). They are generally of a non-mechanistic nature and involve no knowledge of the actual processes involved, which is a severe limitation when assessing real ecosystems. in this paper, the possibility of using an ecological modelling approach as a complement or an alternative to the use of BCF-based models is discussed. The paper gives an overview of ecological and ecosystem modelling and examples of studies where ecosystem models have been used in association to ecological risk assessment studies for other pollutants than radionuclides. It also discusses the potential to use this technique in exposure assessments of radionuclides with a few examples from the safety assessment work performed by the Swedish nuclear fuel and waste management company (SKB). Finally there is a comparison of the characteristics of ecosystem models and traditionally exposure models for radionuclides used to estimate the radionuclide exposure of biota. The evaluation of ecosystem models already applied in safety assessments has shown that the ecosystem approach is possible to use to assess exposure to biota, and that it can handle many of the modelling problems identified related to BCF-models. The findings in this paper suggest that both national and international assessment frameworks for protection of the environment from ionising radiation would benefit from striving to adopt methodologies based on ecologically sound principles and

Exposure Assessment of Diesel Bus Emissions

Directory of Open Access Journals (Sweden)

Werner Hofmann

2006-12-01

Full Text Available The goal of this study was to measure ultrafine particle concentrations with diameters less than 1 μm emitted by diesel buses and to assess resulting human exposure levels. The study was conducted at the Woolloongabba Busway station in Brisbane, Australia in the winter months of 2002 during which temperature inversions frequently occurred. Most buses that utilize the station are fuelled by diesel, the exhaust of which contains a significant quantity of particle matter. Passengers waiting at the station are exposed to these particles emitted from the buses. During the course of this study, passenger census was conducted, based on video surveillance, yielding person-by-person waiting time data. Furthermore, a bus census revealed accurate information about the total number of diesel versus Compressed Natural Gas (CNG powered buses. Background (outside of the bus station and platform measurements of ultrafine particulate number size distributions were made to determine ambient aerosol concentrations. Particle number exposure concentration ranges from 10 and 40 to 60% of bus related exhaust fumes. This changes dramatically when considering the particle mass exposure concentration, where most passengers are exposed to about 50 to 80% of exhaust fumes. The obtained data can be very significant for comparison with similar work of this type because it is shown in previous studies that exhaust emissions causes cancer in laboratory animals. It was assumed that significant differences between platform and background distributions were due to bus emissions which, combined with passenger waiting times, yielded an estimate of passenger exposure to ultrafine particles from diesel buses. From an exposure point of view, the Busway station analyzed resembles a street canyon. Although the detected exhaust particle concentration at the outbound platform is found to be in the picogram range, exposure increases with the time passengers spend on the platform

Assessing asbestos exposure potential in nonindustrial settings.

Science.gov (United States)

Chang, S N; White, L E; Scott, W D

1987-01-01

The presence of asbestos containing materials (ACM) in office and commercial buildings is a significant environmental problem. Asbestosis, mesothelioma and lung cancer have been linked with industrial exposure to airborne asbestos. The extensive use of asbestos products in buildings has raised concerns about the widespread exposure of the general public to asbestos in nonoccupational settings. The presence of asbestos in a building does not necessarily mean that significant exposure of the occupants of the building has occurred, but it is important that the asbestos be monitored regularly to ensure that fibers do not become airborne. If ACM are contained within a matrix and not disturbed, exposure is unlikely. However, if the asbestos becomes friable (crumbling) or if building maintenance, repair, renovation or other activities disturb ACM, airborne asbestos fibers may be a source of exposure to the occupants of the building. Currently, asbestos exposure assessment is conducted by a phase contrast light microscope (PCM) technique. Due to its inherent limitation in resolution and the generic counting rules used, analysis by the PCM method underestimates the airborne asbestos fiber concentration as compared to analysis by transmission electron microscopy (TEM). It is important that the air monitoring results analyzed by PCM be interpreted carefully in conjunction with a survey by a professional to judge the physical condition of the ACM in buildings. Exposure levels to airborne asbestos fibers vary from day to day and depend on the physical condition of the material involved and the type of operating and maintenance program in place.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of temperature on the toxicity of zinc to the earthworm Eisenia fetida

Energy Technology Data Exchange (ETDEWEB)

Spurgeon, D.J.; Tomlin, M.A.; Hopkin, S.P. [Univ. of Reading (United Kingdom)

1997-02-01

A range of toxicity tests have been proposed to assess the potential hazards of pollutants to earthworms. Of these, the two acute toxicity tests using Eisenia fetida recommended by the OECD and EEC have become routinely used in the risk assessment and regulation of new and existing chemicals. In addition to the acute tests, procedures have also been proposed for measuring the sub-lethal effects of chemicals on parameter such as reproduction and weight change. In both the lethal and sub-lethal toxicity tests developed with worms, attempts have been made to standardise test conditions to allow results from different laboratories to be directly compared. However, variability in exposure conditions and responses are fundamental to determine the effects of pollutants under natural conditions. In the field, conditions such as light, moisture availability, pH, temperature and humidity all fluctuate over time. Such variations affect both the sensitivity and exposure of individuals to toxic chemicals. Hence when evaluating the potential effects of pollutants, it may be important to known how changes in test conditions influence toxicity. This study assessed the effects of different temperatures on the lethal and sub-lethal toxicity of zinc for the earthworm Eisenia fetida. 23 refs., 1 fig., 1 tab.

Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale.

Science.gov (United States)

Caudeville, Julien; Bonnard, Roseline; Boudet, Céline; Denys, Sébastien; Govaert, Gérard; Cicolella, André

2012-08-15

Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: - identify and manage geographic areas where hotspot exposures are a potential risk to human health; and - reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km(2) regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. Copyright © 2012 Elsevier B.V. All rights reserved.

Assessment of mankind's exposure through his environment: new tools and aid to decision - Colloquium report

International Nuclear Information System (INIS)

Thierry-Mieg, Morgane; Rousset, Marine; Varkados-Lemarechal, Margaret

2012-01-01

During this colloquium, the different sessions addressed environmental measurement strategies to assess mankind's exposure, the use and the interpretation of exposure bio-markers, the estimation and reconstruction of exposures (integrated modelling, model-measurement coupling), the organization and motives of dialogue between involved parties. Round tables addressed topics such as: measurement strategies and objectives, bio-availability of soil pollutants, approaches and tools for exposure assessment, new methodological strategies for the assessment of chemical exposure, interpretation of bio-markers, reference toxicological values, interest of bio-monitoring in professional environment, transcriptomic analysis, evolutions in the characterization of genotoxic hazards, a tool for the assessment of the exposure of newborn children to pesticides, and so on

Hematologic status of mice submitted to sublethal total body irradiation with mixed neutron-gamma radiation

International Nuclear Information System (INIS)

Herodin, F.; Court, L.

1989-01-01

The hematologic status of mice exposed to sublethal whole body irradiation with mixed neutron-gamma radiation (mainly neutrons) is studied. A slight decrease of the blood cell count is still observed below 1 Gy. The recovery of bone marrow granulocyte-macrophage progenitors seems to require more time than after pure gamma irradiation [fr

Methyldibromo glutaronitrile: clinical experience and exposure-based risk assessment.

Science.gov (United States)

Zachariae, Claus; Rastogi, Suresh; Devantier, Charlotte; Menné, Torkil; Johansen, Jeanne Duus

2003-03-01

In the year 2000, the level of methyldibromo glutaronitrile (MDGN) allergy in dermatology clinics in Europe exceeded the level of allergies to all other preservatives, with a prevalence of 3.5%. In the present study, cases of primary sensitization and elicitation to MDGN due to cosmetic products were collected over an 8-month period at the Department of Dermatology, Gentofte University Hospital. The aim was to identify the products related to hand eczema, assess exposure to MDGN in these products and relate the findings to results from a newly developed updated risk assessment model for contact allergy. Out of 24 patients with a positive patch test to MDGN, 17 patients with hand eczema were identified. In 11 of these patients, cosmetic products used in relation to the onset of the disease were shown to contain MDGN (65%). In 8 of these 11 cases, primary sensitization was probable, 5 due to hand/body lotions and 3 due to lotions and/or liquid hand soap. Chemical analysis of 12 products showed that lotions contained 149-390 ppm of MDGN, liquid hand soap 144-399 ppm, a rinsing cream 293 ppm and shampoos 78-79 ppm. The shampoo exposure was not of certain relevance to the eczema. Applying the newly developed updated risk assessment model showed that the concentrations of MDGN in lotions of 149-390 ppm exceeded the calculated maximum acceptable exposure level for MDGN, which would be expected to lead to sensitization in consumers using such products, as seen in the current study. The present cases and updated exposure-based risk assessment process add to the evidence and need for re-defining safe-use concentrations of MDGN in cosmetic products.

Harmonization of future needs for dermal exposure assessment and modeling : a workshop report

NARCIS (Netherlands)

Marquart, H.; Maidment, S.; Mcclaflin, J.L.; Fehrenbacher, M.C.

2001-01-01

Dermal exposure assessment and modeling is still in early phases of development. This article presents the results of a workshop organized to harmonize the future needs in this field. Methods for dermal exposure assessment either assess the mass of contaminant that is transferred to the skin, or the

Comparative risk assessment of the first-generation anticoagulant rodenticide diphacinone to raptors

Science.gov (United States)

Rattner, Barnett A.; Lazarus, Rebecca S.; Eisenreich, Karen M.; Horak, Katherine E.; Volker, Steven F.; Campton, Christopher M.; Eisemann, John D.; Meteyer, Carol U.; Johnson, John J.

2012-01-01

New regulatory restrictions have been placed on the use of some second-generation anticoagulant rodenticides in the United States, and in some situations this action may be offset by expanded use of first-generation compounds. We have recently conducted several studies with captive adult American kestrels and eastern screech-owls examining the toxicity of diphacinone (DPN) using both acute oral and short-term dietary exposure regimens. Diphacinone evoked overt signs of intoxication and lethality in these raptors at exposure doses that were 20 to 30 times lower than reported for traditionally used wildlife test species (mallard and northern bobwhite). Sublethal exposure of kestrels and owls resulted in prolonged clotting time, reduced hematocrit, and/or gross and histological evidence of hemorrhage at daily doses as low as 0.16 mg DPN/kg body weight. Findings also demonstrated that DPN was far more potent in short-term 7-day dietary studies than in single-day acute oral exposure studies. Incorporating these kestrel and owl data into deterministic and probabilistic risk assessments indicated that the risks associated with DPN exposure for raptors are far greater than predicted in analyses using data from mallards and bobwhite. These findings can assist natural resource managers in weighing the costs and benefits of anticoagulant rodenticide use in pest control and eradication programs.

A spatiotemporal multi-hazard exposure assessment based on property data

Science.gov (United States)

Fuchs, Sven; Keiler, Margreth; Zischg, Andreas

2016-04-01

The paper presents a nation-wide spatially explicit object-based assessment of buildings and citizens exposed to natural hazards in Austria, including river flooding, torrential flooding, and snow avalanches. The assessment was based on two different datasets, (a) hazard information providing input to the exposure of elements at risk, and (b) information on the building stock combined from different spatial data available on the national level. Hazard information was compiled from two different sources. For torrential flooding and snow avalanches available local-scale hazard maps were used, and for river flooding the results of the countrywide flood modelling eHORA were available. Information on the building stock contained information on the location and size of each building, as well as on the building category and the construction period. Additional information related to the individual floors, such as their height and net area, main purpose and configuration, was included for each property. Moreover, this dataset has an interface to the population register and allowed therefore retrieving the number of primary residents for each building. With the exception of sacral buildings, an economic module was used to compute the monetary value of buildings using (a) the information of the building register such as building type, number of storeys and utilisation, and (b) regionally averaged construction costs. It is shown that the repeatedly-stated assumption of increasing exposure due to continued population growth and related increase in assets has to be carefully evaluated by the local development of building stock. While some regions have shown a clearly above-average increase in assets, other regions were characterised by a below-average development. This mirrors the topography of the country, but also the different economic activities. While hotels and hostels are extraordinary prone to torrential flooding, commercial buildings as well as buildings used for

Development of exposure scenarios for CERCLA risk assessments at the Savannah River Site

International Nuclear Information System (INIS)

Nix, D.W.; Immel, J.W.; Phifer, M.A.

1992-01-01

A CERCLA Baseline Risk Assessment (BRA) is performed to determine if there are any potential risks to human health and the environment from waste unit at SRS. The SRS has numerous waste units to evaluate in the RFMU and CMS/FS programs and, in order to provide a consistent approach, four standard exposure scenarios were developed for exposure assessments to be used in human health risk assessments. The standard exposure scenarios are divided into two temporal categories: (a) Current Land Use in the BRA, and (b) Future Land Use in the RERA. The Current Land Use scenarios consist of the evaluation of human health risk for Industrial Exposure (of a worker not involved in waste unit characterization or remediation), a Trespasser, a hypothetical current On-site Resident, and an Off-site Resident. The Future Land Use scenario considers exposure to an On-site Resident following termination of institutional control in the absence of any remedial action (No Action Alternative), as well as evaluating potential remedial alternatives against the four scenarios from the BRA. A critical facet in the development of a BRA or RERA is the scoping of exposure scenarios that reflect actual conditions at a waste unit, rather than using factors such as EPA Standard Default Exposure Scenarios (OSWER Directive 9285.6-03) that are based on upper-bound exposures that tend to reflect worst case conditions. The use of site-specific information for developing risk assessment exposure scenarios will result in a more realistic estimate of Reasonable Maximum Exposure for SRS waste units

Development of exposure scenarios for CERCLA risk assessments at the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

Nix, D.W.; Immel, J.W. [Westinghouse Savannah River Co., Aiken, SC (United States); Phifer, M.A. [Tennessee Univ., Knoxville, TN (United States). Dept. of Civil Engineering

1992-12-31

A CERCLA Baseline Risk Assessment (BRA) is performed to determine if there are any potential risks to human health and the environment from waste unit at SRS. The SRS has numerous waste units to evaluate in the RFMU and CMS/FS programs and, in order to provide a consistent approach, four standard exposure scenarios were developed for exposure assessments to be used in human health risk assessments. The standard exposure scenarios are divided into two temporal categories: (a) Current Land Use in the BRA, and (b) Future Land Use in the RERA. The Current Land Use scenarios consist of the evaluation of human health risk for Industrial Exposure (of a worker not involved in waste unit characterization or remediation), a Trespasser, a hypothetical current On-site Resident, and an Off-site Resident. The Future Land Use scenario considers exposure to an On-site Resident following termination of institutional control in the absence of any remedial action (No Action Alternative), as well as evaluating potential remedial alternatives against the four scenarios from the BRA. A critical facet in the development of a BRA or RERA is the scoping of exposure scenarios that reflect actual conditions at a waste unit, rather than using factors such as EPA Standard Default Exposure Scenarios (OSWER Directive 9285.6-03) that are based on upper-bound exposures that tend to reflect worst case conditions. The use of site-specific information for developing risk assessment exposure scenarios will result in a more realistic estimate of Reasonable Maximum Exposure for SRS waste units.

An assessment of residential exposure to environmental noise at a shipping port.

Science.gov (United States)

Murphy, Enda; King, Eoin A

2014-02-01

The World Health Organisation has recently acknowledged that contrary to the trend for other environmental stressors, noise exposure is increasing in Europe. However, little research has been conducted on environmental noise exposure to handling activity at shipping ports. This paper reports on research examining the extent of noise exposure for residents within the vicinity of Dublin Port, Ireland using the nation's largest port terminal as a proxy for port noise. In order to assess the level of exposure in the area, long-term measurements were undertaken at the most exposed residential façade for a period of 45days to determine the extent of night-time exposure that was above levels recommended by the World Health Organisation. The indicators L90, Leq and LMax were used to determine exposure levels. The results show that exposure is above night-time guideline limits set down by the WHO, above Irish levels for the assessment of noise mitigation and highlight the extent to which port noise can be a significant environmental stressor. The research also investigated the extent of low-frequency noise (which is associated with greater health issues) from night-time port handling activity and found a significant low-frequency component indicating the negative health issues that might arise from port noise exposure more generally. We also undertook semi-structured interviews with residents to qualitatively assess the self-reported impact of prolonged night-time noise exposure for local residents. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analysis of cell cycle regulated and regulating proteins following exposure of lung derived cells to sub-lethal doses of a-rays

Science.gov (United States)

Trani, D.; Claudio, P. P.; Cassone, M.; Lucchetti, C.; D'Agostino, L.; Caputi, M.; Giordano, A.

Introduction Since the last century mankind had to face an increased exposure to man made and natural sources of radiation Radiation represents a therapeutic instrument for radiosensitive cancers as well as a cytotoxic agent for normal human tissues The effects of prolonged exposure to low doses of high energy radiation are still not well-known at the molecular and clinical level Understanding their molecular effects will aid in developing more tailored therapeutic strategies as well as implementing radio-protective measures essential prerequisite for the long-time permanence of men in space Objective of the study The general aim of this study was to evaluate the susceptibility and the response of lung epithelial cells to DNA damage induced by ionizing radiations We decided to study a panel of epithelial bronchial cell lines because of their fast-growth rate and their prominent exposure to both environmental and medical radiations The specific objective of our study was to qualitatively and semi-quantitatively assess the involvement and behaviour of selected genes in DNA damage DNA-repair mechanisms and apoptosis which follow radiation exposure with the aim to determine the involvement of the most promising targets for the early detection of radiation-mediated lung damage before chronic disease develops Methods Four epithelial cell lines one normal and three neoplastic were selected in order to detect and compare survival cell cycle and protein expression differences related to their different genetic asset

Exposure assessment strategies for non-routine work operations (NORWO)

International Nuclear Information System (INIS)

Lew, V.; Johnson, J.; Chiusano, S.; McLouth, L.

1993-01-01

This meeting is the second in a series of a cooperative effort between the Industrial Hygiene Division of the Office of Health (EH-40) and the Office of Oversight (EM-23) to gain input for the development of a section on NORWO exposure assessment in the Exposure Assessment Strategies and HAZWOPER technical guidance manuals. The first day of the meeting was dedicated to a seminar relating to AIHA Strategy for Occupational Exposure Assessment to NORWO situations. Jeff Miller and Tom Weeda of Radian were the course instructors. The course covered how the elements of basic characterization, prioritization, monitoring and decision making could apply to NORWO situations. Several examples of applications of statistical analysis for decision making were illustrated. In addition, the seminar brought forth some points that need additional examination before the strategy can be applied to NORWO. They are: should qualitative and semi-quantitative data be applied to statistical decision making; should professional judgment be balanced with an acceptable degree of statistical certainty; and the need for development of a standardized application of statistics for the DOE Health ampersand Safety community. The remaining two days of the meeting were devoted to the continued development of guidelines to measure and document, in a technically correct and consistent manner, the exposures DOE environmental restoration and waste management (ERWM) workers receive during NORWO and reflects the perspectives and experiences of the attendees. Formal presentations were given by representatives from Hanford and INEL

Advances in exposure and toxicity assessment of particulate matter: An overview of presentations at the 2009 Toxicology and Risk Assessment Conference

International Nuclear Information System (INIS)

Gunasekar, Palur G.; Stanek, Lindsay W.

2011-01-01

The 2009 Toxicology and Risk Assessment Conference (TRAC) session on 'Advances in Exposure and Toxicity Assessment of Particulate Matter' was held in April 2009 in West Chester, OH. The goal of this session was to bring together toxicology, geology and risk assessment experts from the Department of Defense and academia to examine issues in exposure assessment and report on recent epidemiological findings of health effects associated with particulate matter (PM) exposure. Important aspects of PM exposure research are to detect and monitor low levels of PM with various chemical compositions and to assess the health risks associated with these exposures. As part of the overall theme, some presenters discussed collection methods for sand and dust from Iraqi and Afghanistan regions, health issues among deployed personnel, and future directions for risk assessment research among these populations. The remaining speakers focused on the toxicity of ultrafine PM and the characterization of aerosols generated during ballistic impacts of tungsten heavy alloys.

Enhancement of committed hematopoietic stem cell colony formation by nandrolone decanoate after sublethal whole body irradiation

Energy Technology Data Exchange (ETDEWEB)

Gallicchio, V.S.; Chen, M.G.; Watts, T.D.

1984-11-01

The ability of an anabolic steroid, nandrolone decanoate, to increase committed topoietic stem cell (CFU-gm, CFU-e, and BFU-e) colony formation after sublethal irradiation was evaluated. Immediately after receiving whole body irradiation and on the next two days, each mouse was injected intraperitoneally with nandrolone decanoate (1.25 mg) in propylene glycol. Irradiated control mice received only propylene glycol. Compared to controls, drug-treated mice showed marked peripheral blood leukocytosis and more stable packed red cell volume. Drug-treated mice also demonstrated increased erythropoiesis, as CFU-e/BFU-e concentrations from both marrow (9% to 581%) and spleen (15% to 797%) were elevated. Granulopoiesis was increased similarly, as CFU-gm concentrations from marrow (38% to 685%) and spleen (9% to 373%) were elevated. These results demonstrate that nandrolone decanoate enhances hematopoietic stem cell recovery after sublethal whole body irradiation. This suggests that following hematopoietic suppression, nandrolone decanoate may stimulate the recovery of hematopoiesis at the stem cell level and in peripheral blood.

Enhancement of committed hematopoietic stem cell colony formation by nandrolone decanoate after sublethal whole body irradiation

International Nuclear Information System (INIS)

Gallicchio, V.S.; Chen, M.G.; Watts, T.D.

1984-01-01

The ability of an anabolic steroid, nandrolone decanoate, to increase committed topoietic stem cell (CFU-gm, CFU-e, and BFU-e) colony formation after sublethal irradiation was evaluated. Immediately after receiving whole body irradiation and on the next two days, each mouse was injected intraperitoneally with nandrolone decanoate (1.25 mg) in propylene glycol. Irradiated control mice received only propylene glycol. Compared to controls, drug-treated mice showed marked peripheral blood leukocytosis and more stable packed red cell volume. Drug-treated mice also demonstrated increased erythropoiesis, as CFU-e/BFU-e concentrations from both marrow (9% to 581%) and spleen (15% to 797%) were elevated. Granulopoiesis was increased similarly, as CFU-gm concentrations from marrow (38% to 685%) and spleen (9% to 373%) were elevated. These results demonstrate that nandrolone decanoate enhances hematopoietic stem cell recovery after sublethal whole body irradiation. This suggests that following hematopoietic suppression, nandrolone decanoate may stimulate the recovery of hematopoiesis at the stem cell level and in peripheral blood

Evaluation of Pyrethrin Formulations on Dengue/Dengue Haemorrhagic Fever Vectors in the Laboratory and Sublethal Effects

Directory of Open Access Journals (Sweden)

S Sulaiman

2007-12-01

Full Text Available In Southeast Asia, Aedes aegypti (L. has been incriminated as principal vector of dengue viruses and Ae. albopictus as the secondary vector of dengue fever. Therefore, the aim of this study was to investigate the effectiveness of three for-mula¬tions of pyrethrin derived from Tanacetum cinerariaefolium against the dengue/dengue haemorrhagic fever vectors Aedes aegypti and Ae. albopictus in the laboratory. The testings employed 2 methodologies: the WHO Larval Bioassay and WHO Adult Bioassay. The results showed that all the three pyrethrin formulations had larvicidal and adulticidal activi-ties. The impact of the sublethal doses of pyrethrin formulations on Aedes spp. larvae resulted in 4-6% of alive adult emergence compared to 90% of Ae. aegypti emerging adults and 96% Ae. albopictus alive adult emergence in the control. The impact of sublethal doses of the pyrethrin formulations caused very low fecundity on both Aedes spp. compared to the control (P< 0.05.

Evaluation of Pyrethrin Formulations on Dengue/Dengue Haemorrhagic Fever Vectors in the Laboratory and Sublethal Effects

Directory of Open Access Journals (Sweden)

S Sulaiman

2007-11-01

Full Text Available In Southeast Asia, Aedes aegypti (L. has been incriminated as principal vector of dengue viruses and Ae. albopictus as the secondary vector of dengue fever. Therefore, the aim of this study was to investigate the effectiveness of three for-mula¬tions of pyrethrin derived from Tanacetum cinerariaefolium against the dengue/dengue haemorrhagic fever vectors Aedes aegypti and Ae. albopictus in the laboratory. The testings employed 2 methodologies: the WHO Larval Bioassay and WHO Adult Bioassay. The results showed that all the three pyrethrin formulations had larvicidal and adulticidal activi-ties. The impact of the sublethal doses of pyrethrin formulations on Aedes spp. larvae resulted in 4-6% of alive adult emergence compared to 90% of Ae. aegypti emerging adults and 96% Ae. albopictus alive adult emergence in the control. The impact of sublethal doses of the pyrethrin formulations caused very low fecundity on both Aedes spp. compared to the control (P< 0.05.

Induction of specific Escherichia coli genes by sublethal treatments with alkylating agents.

OpenAIRE

Volkert, M R; Nguyen, D C

1984-01-01

Fusions of the lac operon to genes induced by treatment with sublethal levels of alkylating agents have been selected from random insertions of the Mu-dl(ApRlac) phage by screening for induction of beta-galactosidase activity in the presence of methyl methanesulfonate. Genetic analysis reveals that these fusions resulted from insertion of Mu-dl(ApRlac) into two regions of the chromosome. One region (aidA) is near his and, based on phenotypic effects, appears to represent insertion into the al...

A Review of Exposure Assessment Methods in Epidemiological Studies on Incinerators

Directory of Open Access Journals (Sweden)

Michele Cordioli

2013-01-01

Full Text Available Incineration is a common technology for waste disposal, and there is public concern for the health impact deriving from incinerators. Poor exposure assessment has been claimed as one of the main causes of inconsistency in the epidemiological literature. We reviewed 41 studies on incinerators published between 1984 and January 2013 and classified them on the basis of exposure assessment approach. Moreover, we performed a simulation study to explore how the different exposure metrics may influence the exposure levels used in epidemiological studies. 19 studies used linear distance as a measure of exposure to incinerators, 11 studies atmospheric dispersion models, and the remaining 11 studies a qualitative variable such as presence/absence of the source. All reviewed studies utilized residence as a proxy for population exposure, although residence location was evaluated with different precision (e.g., municipality, census block, or exact address. Only one study reconstructed temporal variability in exposure. Our simulation study showed a notable degree of exposure misclassification caused by the use of distance compared to dispersion modelling. We suggest that future studies (i make full use of pollution dispersion models; (ii localize population on a fine-scale; and (iii explicitly account for the presence of potential environmental and socioeconomic confounding.

Sublethal effect of neem extract on mediterranean fruit fly adults

Directory of Open Access Journals (Sweden)

Márcio Alves Silva

2013-03-01

Full Text Available The sublethal effect of extracts of Azadirachta indica on Ceratitis capitata was evaluated. Two pairs of flies were treated in plastic tubes with cotton placed in plastic cages. An artificial diet (hydrolyzed protein + sugar was provided ad libitum. The extracts affected significantly the longevity of C. capitata. The pre-oviposition period were not significantly affected by the extracts. The A. indica branches extracted with dichloromethane (888 ppm affected significantly the fecundity and fertility, reducing the number of eggs laid to approximately 80 % and the egg hatching by 30 % at the 8th day. Therefore, the neem branches extracted with dichloromethane affected the reproduction of C. capitata.

Assessment of human exposure to environmental sources of nickel in Europe: Inhalation exposure.

Science.gov (United States)

Buekers, Jurgen; De Brouwere, Katleen; Lefebvre, Wouter; Willems, Hanny; Vandenbroele, Marleen; Van Sprang, Patrick; Eliat-Eliat, Maxime; Hicks, Keegan; Schlekat, Christian E; Oller, Adriana R

2015-07-15

The paper describes the inhalation nickel (Ni) exposure of humans via the environment for the regional scale in the EU, together with a tiered approach for assessing additional local exposure from industrial emissions. The approach was designed, in the context of REACH, for the purpose of assessing and controlling emissions and air quality in the neighbourhood of Ni producers and downstream users. Two Derived No Effect Level (DNEL) values for chronic inhalation exposure to total Ni in PM10 (20 and 60ngNi/m(3)) were considered. The value of 20ngNi/m(3) is the current EU air quality guidance value. The value of 60ngNi/m(3) is derived here based on recently published Ni data (Oller et al., 2014). Both values are protective for respiratory toxicity and carcinogenicity but differ in the application of toxicokinetic adjustments and cancer threshold considerations. Estimates of air Ni concentrations at the European regional scale were derived from the database of the European Environment Agency. The 50th and 90th percentile regional exposures were below both DNEL values. To assess REACH compliance at the local scale, measured ambient air data are preferred but are often unavailable. A tiered approach for the use of modelled ambient air concentrations was developed, starting with the application of the default EUSES model and progressing to more sophisticated models. As an example, the tiered approach was applied to 33 EU Ni sulphate producers' and downstream users' sites. Applying the EUSES model demonstrates compliance with a DNEL of 60ngNi/m(3) for the majority of sites, while the value of the refined modelling is demonstrated when a DNEL of 20ngNi/m(3) is considered. The proposed approach, applicable to metals in general, can be used in the context of REACH, for refining the risk characterisation and guiding the selection of risk management measures. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

ASSESSING CHILDREN'S EXPOSURES TO PESTICIDES: AN IMPORTANT APPLICATION OF THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION MODEL (SHEDS)

Science.gov (United States)

Accurately quantifying human exposures and doses of various populations to environmental pollutants is critical for the Agency to assess and manage human health risks. For example, the Food Quality Protection Act of 1996 (FQPA) requires EPA to consider aggregate human exposure ...

Taking Multiple Exposure Into Account Can Improve Assessment of Chemical Risks.

Science.gov (United States)

Clerc, Frédéric; Bertrand, Nicolas Jean Hyacinthe; La Rocca, Bénédicte

2017-12-15

During work, operators may be exposed to several chemicals simultaneously. Most exposure assessment approaches only determine exposure levels for each substance individually. However, such individual-substance approaches may not correctly estimate the toxicity of 'cocktails' of chemicals, as the toxicity of a cocktail may differ from the toxicity of substances on their own. This study presents an approach that can better take into account multiple exposure when assessing chemical risks. Almost 30000 work situations, monitored between 2005 and 2014 and recorded in two French databases, were analysed using MiXie software. The algorithms employed in MiXie can identify toxicological classes associated with several substances, based on the additivity of the selected effects of each substance. The results of our retrospective analysis show that MiXie was able to identify almost 20% more potentially hazardous situations than identified using a single-substance approach. It therefore appears essential to review the ways in which multiple exposure is taken into account during risk assessment. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Toxicity and sublethal effects of seven insecticides to eggs of the flower bug Orius insidiosus (Say) (Hemiptera: Anthocoridae).

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Moscardini, Valéria Fonseca; Gontijo, Pablo da Costa; Carvalho, Geraldo Andrade; Oliveira, Rodrigo Lopes de; Maia, Jader Braga; Silva, Fernanda Fonseca e

2013-07-01

The predatory bug Orius insidiosus is an important biological control agent of several insect pests, and is one of the most commonly used species in biological control programs worldwide. This study assessed the lethal and sublethal effects of insecticides on this species through life table, and classified the insecticides according to the definitions of toxicity given by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). A bioassay was carried out using a completely randomized design with eight treatments and 40 replicates. Eggs of O. insidiosus laid naturally in plant stems were immersed in aqueous solutions of the chemical products. Egg viability, duration of the embryonic period, survival of nymphs, and duration of the nymphal period were assessed daily. Insects that reached adulthood were paired and their reproduction assessed. The number of eggs produced and the survival of adults were assessed daily. The insecticides abamectin, cartap hydrochloride, spirotetramat+imidacloprid, and flubendiamid were classified as harmful. Pyriproxyfen and rynaxypyr were categorized as harmless and pymetrozine was classified as slightly harmful. Pyriproxyfen affected the population parameters rm, GT, DT, and λ, whereas other insecticides did not. Copyright © 2013 Elsevier Ltd. All rights reserved.

Frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system.

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Cizauskas, Carrie A; Bellan, Steven E; Turner, Wendy C; Vance, Russell E; Getz, Wayne M

2014-09-01

Few studies have examined host-pathogen interactions in wildlife from an immunological perspective, particularly in the context of seasonal and longitudinal dynamics. In addition, though most ecological immunology studies employ serological antibody assays, endpoint titre determination is usually based on subjective criteria and needs to be made more objective. Despite the fact that anthrax is an ancient and emerging zoonotic infectious disease found world-wide, its natural ecology is not well understood. In particular, little is known about the adaptive immune responses of wild herbivore hosts against Bacillus anthracis. Working in the natural anthrax system of Etosha National Park, Namibia, we collected 154 serum samples from plains zebra (Equus quagga), 21 from springbok (Antidorcas marsupialis) and 45 from African elephants (Loxodonta africana) over 2-3 years, resampling individuals when possible for seasonal and longitudinal comparisons. We used enzyme-linked immunosorbent assays to measure anti-anthrax antibody titres and developed three increasingly conservative models to determine endpoint titres with more rigourous, objective mensuration. Between 52 and 87% of zebra, 0-15% of springbok and 3-52% of elephants had measurable anti-anthrax antibody titres, depending on the model used. While the ability of elephants and springbok to mount anti-anthrax adaptive immune responses is still equivocal, our results indicate that zebra in ENP often survive sublethal anthrax infections, encounter most B. anthracis in the wet season and can partially booster their immunity to B. anthracis. Thus, rather than being solely a lethal disease, anthrax often occurs as a sublethal infection in some susceptible hosts. Though we found that adaptive immunity to anthrax wanes rapidly, subsequent and frequent sublethal B. anthracis infections cause maturation of anti-anthrax immunity. By triggering host immune responses, these common sublethal infections may act as

Effects of Sub-lethal Concentrations of Silver Nanoparticles on a Simulated Intestinal Prokaryotic–Eukaryotic Interface

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Elisa Garuglieri

2018-01-01

Full Text Available Nanotechnology applications are expected to bring a range of benefits to the food sector, aiming to provide better quality and conservation. In this research, the physiological response of both an Escherichia coli mono-species biofilm and Caco-2 intestinal cells to sub-lethal concentrations of silver nanoparticles (AgNPs has been investigated. In order to simulate the anaerobic and aerobic compartments required for bacteria and intestinal cells growth, a simplified semi-batch model based on a transwell permeable support was developed. Interaction between the two compartments was obtained by exposing Caco-2 intestinal cells to the metabolites secreted by E. coli biofilm after its exposure to AgNPs. To the best of the authors’ knowledge, this study is the first to investigate the effect of AgNPs on Caco-2 cells that takes into consideration previous AgNP-intestinal biofilm interactions, and at concentrations mimicking real human exposure. Our data show that 1 μg/mL AgNPs in anaerobic conditions (i promote biofilm formation up to 2.3 ± 0.3 fold in the first 72 h of treatment; (ii increase reactive oxygen species (ROS production to 84 ± 21% and change the physiological status of microbial cells after 96 h of treatment; (iii seriously affect a 72-h old established biofilm, increasing the level of oxidative stress to 86 ± 21%. Moreover, the results indicate that oxygen renders the biofilm more adequate to counteract AgNP effects. Comet assays on Caco-2 cells demonstrated a protective role of biofilm against the genotoxic effect of 1 μg/mL AgNPs on intestinal epithelial cells.