Nutrient removal and biomass production: advances in microalgal biotechnology for wastewater treatment.

Science.gov (United States)

Abinandan, Sudharsanam; Subashchandrabose, Suresh R; Venkateswarlu, Kadiyala; Megharaj, Mallavarapu

2018-05-17

Owing to certain drawbacks, such as energy-intensive operations in conventional modes of wastewater treatment (WWT), there has been an extensive search for alternative strategies in treatment technology. Biological modes for treating wastewaters are one of the finest technologies in terms of economy and efficiency. An integrated biological approach with chemical flocculation is being conventionally practiced in several-sewage and effluent treatment plants around the world. Overwhelming responsiveness to treat wastewaters especially by using microalgae is due to their simplest photosynthetic mechanism and ease of acclimation to various habitats. Microalgal technology, also known as phycoremediation, has been in use for WWT since 1950s. Various strategies for the cultivation of microalgae in WWT systems are evolving faster. However, the availability of innovative approaches for maximizing the treatment efficiency, coupled with biomass productivity, remains the major bottleneck for commercialization of microalgal technology. Investment costs and invasive parameters also delimit the use of microalgae in WWT. This review critically discusses the merits and demerits of microalgal cultivation strategies recently developed for maximum pollutant removal as well as biomass productivity. Also, the potential of algal biofilm technology in pollutant removal, and harvesting the microalgal biomass using different techniques have been highlighted. Finally, an economic assessment of the currently available methods has been made to validate microalgal cultivation in wastewater at the commercial level.

Microalgal Cultivation in Treating Liquid Digestate from Biogas Systems.

Science.gov (United States)

Xia, Ao; Murphy, Jerry D

2016-04-01

Biogas production via anaerobic digestion (AD) has rapidly developed in recent years. In addition to biogas, digestate is an important byproduct. Liquid digestate is the major fraction of digestate and may contain high levels of ammonia nitrogen. Traditional processing technologies (such as land application) require significant energy inputs and raise environmental risks (such as eutrophication). Alternatively, microalgae can efficiently remove the nutrients from digestate while producing high-value biomass that can be used for the production of biochemicals and biofuels. Both inorganic and organic carbon sources derived from biogas production can significantly improve microalgal production. Land requirement for microalgal cultivation is estimated as 3% of traditional direct land application of digestate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microalgal production - A close look at the economics

NARCIS (Netherlands)

Norsker, N.H.; Barbosa, M.J.; Vermuë, M.H.; Wijffels, R.H.

2011-01-01

Worldwide, microalgal biofuel production is being investigated. It is strongly debated which type of production technology is the most adequate. Microalgal biomass production costs were calculated for 3 different micro algal production systems operating at commercial scale today: open ponds,

Unexpected associated microalgal diversity in the lichen Ramalina farinacea is uncovered by pyrosequencing analyses.

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Patricia Moya

Full Text Available The current literature reveals that the intrathalline coexistence of multiple microalgal taxa in lichens is more common than previously thought, and additional complexity is supported by the coexistence of bacteria and basidiomycete yeasts in lichen thalli. This replaces the old paradigm that lichen symbiosis occurs between a fungus and a single photobiont. The lichen Ramalina farinacea has proven to be a suitable model to study the multiplicity of microalgae in lichen thalli due to the constant coexistence of Trebouxia sp. TR9 and T. jamesii in long-distance populations. To date, studies involving phycobiont diversity within entire thalli are based on Sanger sequencing, but this method seems to underestimate the diversity. Here, we aim to analyze both the microalgal diversity and its community structure in a single thallus of the lichen R. farinacea by applying a 454 pyrosequencing approach coupled with a careful ad hoc-performed protocol for lichen sample processing prior to DNA extraction. To ascertain the reliability of the pyrosequencing results and the applied bioinformatics pipeline results, the thalli were divided into three sections (apical, middle and basal zones, and a mock community sample was used. The developed methodology allowed 40448 filtered algal reads to be obtained from a single lichen thallus, which encompassed 31 OTUs representative of different microalgae genera. In addition to corroborating the coexistence of the two Trebouxia sp. TR9 and T. jamesii taxa in the same thallus, this study showed a much higher microalgal diversity associated with the lichen. Along the thallus ramifications, we also detected variations in phycobiont distribution that might correlate with different microenvironmental conditions. These results highlight R. farinacea as a suitable material for studying microalgal diversity and further strengthen the concept of lichens as multispecies microecosystems. Future analyses will be relevant to

Microalgal Culture Collection Transfers

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Milford Microalgal culture Collection holds over 200 live cultures representing 13 classes of of algae. The cultures are maintained in three different growing...

Co-cultivation of fungal and microalgal cells as an efficient system for harvesting microalgal cells, lipid production and wastewater treatment.

Science.gov (United States)

Wrede, Digby; Taha, Mohamed; Miranda, Ana F; Kadali, Krishna; Stevenson, Trevor; Ball, Andrew S; Mouradov, Aidyn

2014-01-01

The challenges which the large scale microalgal industry is facing are associated with the high cost of key operations such as harvesting, nutrient supply and oil extraction. The high-energy input for harvesting makes current commercial microalgal biodiesel production economically unfeasible and can account for up to 50% of the total cost of biofuel production. Co-cultivation of fungal and microalgal cells is getting increasing attention because of high efficiency of bio-flocculation of microalgal cells with no requirement for added chemicals and low energy inputs. Moreover, some fungal and microalgal strains are well known for their exceptional ability to purify wastewater, generating biomass that represents a renewable and sustainable feedstock for biofuel production. We have screened the flocculation efficiency of the filamentous fungus A. fumigatus against 11 microalgae representing freshwater, marine, small (5 µm), large (over 300 µm), heterotrophic, photoautotrophic, motile and non-motile strains. Some of the strains are commercially used for biofuel production. Lipid production and composition were analysed in fungal-algal pellets grown on media containing alternative carbon, nitrogen and phosphorus sources contained in wheat straw and swine wastewater, respectively. Co-cultivation of algae and A. fumigatus cells showed additive and synergistic effects on biomass production, lipid yield and wastewater bioremediation efficiency. Analysis of fungal-algal pellet's fatty acids composition suggested that it can be tailored and optimised through co-cultivating different algae and fungi without the need for genetic modification.

Co-cultivation of fungal and microalgal cells as an efficient system for harvesting microalgal cells, lipid production and wastewater treatment.

Directory of Open Access Journals (Sweden)

Digby Wrede

Full Text Available The challenges which the large scale microalgal industry is facing are associated with the high cost of key operations such as harvesting, nutrient supply and oil extraction. The high-energy input for harvesting makes current commercial microalgal biodiesel production economically unfeasible and can account for up to 50% of the total cost of biofuel production. Co-cultivation of fungal and microalgal cells is getting increasing attention because of high efficiency of bio-flocculation of microalgal cells with no requirement for added chemicals and low energy inputs. Moreover, some fungal and microalgal strains are well known for their exceptional ability to purify wastewater, generating biomass that represents a renewable and sustainable feedstock for biofuel production. We have screened the flocculation efficiency of the filamentous fungus A. fumigatus against 11 microalgae representing freshwater, marine, small (5 µm, large (over 300 µm, heterotrophic, photoautotrophic, motile and non-motile strains. Some of the strains are commercially used for biofuel production. Lipid production and composition were analysed in fungal-algal pellets grown on media containing alternative carbon, nitrogen and phosphorus sources contained in wheat straw and swine wastewater, respectively. Co-cultivation of algae and A. fumigatus cells showed additive and synergistic effects on biomass production, lipid yield and wastewater bioremediation efficiency. Analysis of fungal-algal pellet's fatty acids composition suggested that it can be tailored and optimised through co-cultivating different algae and fungi without the need for genetic modification.

An experimental investigation of microalgal dewatering efficiency of belt filter system

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Anjali Sandip

2015-11-01

Full Text Available The objective of this study was to investigate the microalgal dewatering efficiency of a belt filter system for feed concentrations below 10 g dry wt./L. A prototype belt filtration system designed for 50 g dry wt./L microalgal feed concentration was used for this investigation. The highest concentration of microalgal suspension available for testing on the prototype belt filtration system was 6 g dry wt./L obtained from biomass settling tanks at the Lawrence, Kansas domestic wastewater treatment plant. For preparation of feed suspension with concentrations below 10 g dry wt./L, microalgal cultivation was followed by flocculation. A mixed laboratory culture of freshwater species dominated by three eukaryotic green microalgae (Chlorella vulgaris, Scenedesmus sp., and Kirchneriella sp. was cultivated in wastewater effluent. This was followed by flocculation which resulted in a microalgal feed suspension concentration of 4 g dry wt./L. Belt dewatering tests were conducted on microalgal suspensions with feed concentrations of 4 g dry wt./L and 6 g dry wt./L. The maximum microalgal recovery with the belt dewatering system was 46% from the 4 g dry wt./L, and 84% from the 6 g dry wt./L suspensions respectively. The results of this study indicate that microalgal suspension concentrations as low as 6 g dry wt./L can be recovered with a belt filter system improving the overall dewatering efficiency of the system.

Biomass and Neutral Lipid Production in Geothermal Microalgal Consortia

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Bywaters, Kathryn F.; Fritsen, Christian H.

2015-01-01

Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems – in addition to oil-derived fuels (Bird et al., 2011, 2012). Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonally low temperatures on biomass production systems as well as mitigate some of the challenges associated with growing unialgal strains. We assessed community composition, growth rates, biomass, and neutral lipid production of microalgal consortia obtained from geothermal hot springs in the Great Basin/Nevada area that were cultured under different thermal and light conditions. Biomass production rates ranged from 39.0 to 344.1 mg C L−1 day−1. The neutral lipid production in these consortia with and without shifts to lower temperatures and additions of bicarbonate (both environmental parameters that have been shown to enhance neutral lipid production) ranged from 0 to 38.74 mg free fatty acids (FFA) and triacylglycerols (TAG) L−1 day−1; the upper value was approximately 6% of the biomass produced. The higher lipid values were most likely due to the presence of Achnanthidium sp. Palmitic and stearic acids were the dominant free fatty acids. The S/U ratio (the saturated to unsaturated FA ratio) decreased for cultures shifted from their original temperature to 15°C. Biomass production was within the upper limits of those reported for individual strains, and production of neutral lipids was increased with secondary treatment. All results demonstrate a potential of culturing and manipulating resultant microalgal consortia for biomass-based energy production and perhaps even for biofuels. PMID:25763368

Biomass and Neutral Lipid Production in Geothermal Microalgal Consortia

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Kathryn Faye Bywaters

2015-02-01

Full Text Available Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems- in addition to oil-derived fuels (Bird et al., 2011;Bird et al., 2012. Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonally low temperatures on biomass production systems as well as mitigate some of the challenges associated with growing unialgal strains. We assessed community composition, growth rates, biomass and neutral lipid production of microalgal consortia obtained from geothermal hot springs in the Great Basin/Nevada area that were cultured under different thermal and light conditions. Biomass production rates ranged from 368 to 3246 mg C L-1 d-1. The neutral lipid production in these consortia with and without shifts to lower temperatures and additions of bicarbonate (both environmental parameters that have been shown to enhance neutral lipid production ranged from zero to 38.74 mg free fatty acids and triacylglycerols L-1 d-1, the upper value was approximately 6% of the biomass produced. The higher lipid values were most likely due to the presence of Achnanthidium sp. Palmitic and stearic acids were the dominant free fatty acids. The S/U ratio (the saturated to unsaturated FA ratio decreased for cultures shifted from their original temperature to 15°C. Biomass production was within the upper limits of those reported for individual strains, and production of neutral lipids was increased with secondary treatment – all results demonstrate a potential of culturing and manipulating resultant microalgal consortia for biomass-based energy production and perhaps even for biofuels.

Similarity microalgal epiphyte composition on seagrass of Enhalus acoroides and Thalasia hemprichii from different waters

Science.gov (United States)

Hartati, R.; Zainuri, M.; Ambariyanto, A.; Widianingsih; Trianto, A.; Mahendrajaya, R. T.

2018-03-01

The epiphytes are all autotrophic organisms that are permanently attached to rhizomes, roots, and leaves of seagrasses. The epiphyte is an important primary producer for the seagrass ecosystem and contributes significantly to the food chain. This study aims to identify the composition of microepiphyte algae on Enhalus acoroides and Thalassia hemprichii and their similarity levels of both compositions. The 20 leaves samples of E. acoroides and T. hemprichii were observed. The epiphytic microalgae which found on the surface of the seagrass leaves were scrapped, collected in a bottle sample, and fixed with 70 % alcohol and identified into genera. The relation of epiphytic microalgal genera to the location and species of seagrass was analyzed using similarity analysis. The Chrysophyta, Cyanophyta, and Chlorophyta epiphytic microalgal were found. There were similarity variations of the microalgal epiphyte in seagrass of E. acoroides and T. hemprichii and seagrass habitat sites. Morphology and seagrass life affects the abundance and diversity of the epiphytic microalgal attached to the seagrass and it may be associated with the epiphytic lifetime in the seagrass.

Cell disruption and lipid extraction for microalgal biorefineries: A review.

Science.gov (United States)

Lee, Soo Youn; Cho, Jun Muk; Chang, Yong Keun; Oh, You-Kwan

2017-11-01

The microalgae-based biorefinement process has attracted much attention from academic and industrial researchers attracted to its biofuel, food and nutraceutical applications. In this paper, recent developments in cell-disruption and lipid-extraction methods, focusing on four biotechnologically important microalgal species (namely, Chlamydomonas, Haematococcus, Chlorella, and Nannochloropsis spp.), are reviewed. The structural diversity and rigidity of microalgal cell walls complicate the development of efficient downstream processing methods for cell-disruption and subsequent recovery of intracellular lipid and pigment components. Various mechanical, chemical and biological cell-disruption methods are discussed in detail and compared based on microalgal species and status (wet/dried), scale, energy consumption, efficiency, solvent extraction, and synergistic combinations. The challenges and prospects of the downstream processes for the future development of eco-friendly and economical microalgal biorefineries also are outlined herein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling of microalgal metabolism

NARCIS (Netherlands)

Kliphuis, A.M.J.

2010-01-01

Microalgae are a potential source for a wide range of products, such as carotenoids, lipids, hydrogen, protein and starch, which are of interest for food, feed and biofuel applications. Maximization of microalgal product and biomass productivity in (large-scale) outdoor photobioreactors is important

Dependence of carbon dioxide concentration on microalgal carbon dioxide fixation

Energy Technology Data Exchange (ETDEWEB)

Yun, Yeoung Sang; Park, Song Moon [Department of Chemical Engineering, School of Environmental Engineering, Pohang University of Science and Technology, Pohang (Korea); Bolesky, Bohumil [Department of Chemical Engineering, McGill University (Canada)

1999-10-01

Batch cultivation of chlorella vulgaris was carried out under various CO{sub 2} concentrations in order to understand and describe mathematically the CO{sub 2} inhibition of microalgal CO{sub 2} fixation. The volumetric CO{sub 2} transfer coefficient from mixture gas to culture medium was estimated from the volumetric O{sub 2} transfer coefficient obtained experimentally. Using this transfer coefficient and aquatic equilibrium relationship between dissolved inorganic carbons, the behavior of dissolved CO{sub 2} was calculated during microalgal culture. When air containing 0.035%(v/v) CO{sub 2} was supplied into microalgal culture, the fixation rate was limited by CO{sub 2} transfer rate. However, the limitation was disappeared by supplying mixture gas containing above 2%(v/v) CO{sub 2} and the dissolved CO{sub 2} concentration was maintained at the saturated value. In the range of CO{sub 2} partial pressure in the flue gases from thermal power sations and steel-making plants, the microalgal CO{sub 2} fixation rate was inhibited. The CO{sub 2} fixation rate was successfully formulated by a new empirical equation as a function of dissolved CO{sub 2} concentration, which could be useful for modeling and simulating the performance of photobioreaction with enriched CO{sub 2}. Also, it was found that the CO{sub 2} inhibition of microalgal CO{sub 2} fixation was reversible and that microalgal CO{sub 2} fixation process could be stable against a shock of unusually high CO{sub 2} concentration. 29 refs., 8 figs.

Third-generation biofuels: current and future research on microalgal lipid biotechnology

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Li-Beisson Yonghua

2013-11-01

Full Text Available One pressing issue faced by modern societies is to develop renewable energy for transportation. Microalgal biomass offers an attractive solution due to its high (annual surface biomass productivity, efficient conversion of solar energy into chemical energy and the ability to grow on non-agricultural land. Despite these considerable advantages, microalgal biofuels are not yet commercially sustainable. Major challenges lie in improving both cultivation technologies and microalgal strains. A microalgal crop species is yet to emerge. In this review, we focus on researches aiming at understanding and harnessing lipid metabolism in microalgae in view of producing lipid-based biofuels such as biodiesel. Current biotechnological challenges and key progresses made in the development of algal models, genetic tools and lipid metabolic engineering strategies are reviewed. Possible future research directions to increase oil yields in microalgae are also highlighted.

Modelling of green microalgal growth and algal storage processes using wastewater resources

DEFF Research Database (Denmark)

Wágner, Dorottya Sarolta; Plósz, Benedek G.; Valverde Pérez, Borja

2017-01-01

Recent research focuses on the recovery of nutrients, water and energy from wastewater. Microalgal cultivation on wastewater resources is considered as a more sustainable means to produce fertilizers or biofuels. Innovative systems that incorporate microalgal cultivation into conventional wastewa...... have been developed according to the activated sludge modelling (ASM) framework to facilitate the integration with existing modelling frameworks in water treatment. This chapter presents in detail the recently developed ASM-A biokinetic green microalgal process model. The model includes...

Kinetics of inorganic carbon utilization by microalgal biofilm in a flat plate photoreactor

Energy Technology Data Exchange (ETDEWEB)

Lin, Y.H.; Leu, J.Y.; Lan, C.R.; Lin, P.H.P.; Chang, F.L. [Development Center for Biotechnology, Taipei (Taiwan). Dept. for Environmental Program

2003-11-01

A kinetic model was developed to describe inorganic carbon utilization by microalgae biofilm in a flat plate photoreactor. The model incorporates the fundamental mechanisms of diffusive mass transport and biological reaction of inorganic carbon by microalgal biofilm. An advanced numerical technique, the orthogonal collocation method and Gear's method, was employed to solve this kinetic model. The model solutions included the concentration profiles of inorganic carbon in the microalgal biofilm, the growths of suspended microalgae and microalgal biofilm, the effluent concentrations of inorganic carbon, and the flux of inorganic carbon from bulk liquid into biofilm. The batch kinetic test was independently conducted to determine biokinetic parameters used in the microalgal biofilm model simulation while initial thickness of microalgal biofilm were assumed. A laboratory-scale flat plate photoreactor with a high recycle flow rate was set up and conducted to verify the model. The volume of photoreactor is 60 l which yields a hydraulic retention time of 1.67 days. The model-generated inorganic carbon and the suspended microalgae concentration curves agreed well with those obtained in the laboratory-scale test. The fixation efficiencies of HCO{sub 3}{sup -} and CO{sub 2} are 98.5% and 90% at a steady-state condition, respectively. The concentration of suspended microalgal cell reached up to 12 mg/l at a maximum growth rate while the thickness of microalgal biofilm was estimated to be 104 pm at a steady-state condition. The approaches of experiments and model simulation presented in this study could be employed for the design of a flat plate photoreactor to treat CO{sub 2} by microalgal biofilm in a fossil-fuel power plant.

Ultrasonic disintegration of microalgal biomass and consequent improvement of bioaccessibility/bioavailability in microbial fermentation.

Science.gov (United States)

Jeon, Byong-Hun; Choi, Jeong-A; Kim, Hyun-Chul; Hwang, Jae-Hoon; Abou-Shanab, Reda Ai; Dempsey, Brian A; Regan, John M; Kim, Jung Rae

2013-01-01

Microalgal biomass contains a high level of carbohydrates which can be biochemically converted to biofuels using state-of-the-art strategies that are almost always needed to employ a robust pretreatment on the biomass for enhanced energy production. In this study, we used an ultrasonic pretreatment to convert microalgal biomass (Scenedesmus obliquus YSW15) into feasible feedstock for microbial fermentation to produce ethanol and hydrogen. The effect of sonication condition was quantitatively evaluated with emphases on the characterization of carbohydrate components in microalgal suspension and on subsequent production of fermentative bioenergy. Scenedesmus obliquus YSW15 was isolated from the effluent of a municipal wastewater treatment plant. The sonication durations of 0, 10, 15, and 60 min were examined under different temperatures at a fixed frequency and acoustic power resulted in morphologically different states of microalgal biomass lysis. Fermentation was performed to evaluate the bioenergy production from the non-sonicated and sonicated algal biomasses after pretreatment stage under both mesophilic (35°C) and thermophilic (55°C) conditions. A 15 min sonication treatment significantly increased the concentration of dissolved carbohydrates (0.12 g g(-1)), which resulted in an increase of hydrogen/ethanol production through microbial fermentation. The bioconvertibility of microalgal biomass sonicated for 15 min or longer was comparable to starch as a control, indicating a high feasibility of using microalgae for fermentative bioenergy production. Increasing the sonication duration resulted in increases in both algal surface hydrophilicity and electrostatic repulsion among algal debris dispersed in aqueous solution. Scanning electron microscope images supported that ruptured algal cell allowed fermentative bacteria to access the inner space of the cell, evidencing an enhanced bioaccessibility. Sonication for 15 min was the best for fermentative

Superstructure optimization of biodiesel production from microalgal biomass

DEFF Research Database (Denmark)

Rizwan, Muhammad; Lee, Jay H.; Gani, Rafiqul

2013-01-01

In this study, we propose a mixed integer nonlinear programming (MINLP) model for superstructure based optimization of biodiesel production from microalgal biomass. The proposed superstructure includes a number of major processing steps for the production of biodiesel from microalgal biomass...... for the production of biodiesel from microalgae. The proposed methodology is tested by implementing on a specific case study. The MINLP model is implemented and solved in GAMS using a database built in Excel. The results from the optimization are analyzed and their significances are discussed....

Microalgal Mass Culture Room Harvest Records

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The microalgal mass culture room, housed at the NOAA Fisheries' Milford CT laboratory, provides research grade microalgae (phytoplankton) to in-house and...

Two stressors and a community - Effects of hydrological disturbance and a toxicant on freshwater zooplankton

Energy Technology Data Exchange (ETDEWEB)

Stampfli, Nathalie C. [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau (Germany); Knillmann, Saskia [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Department of Ecosystem Analyses, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Liess, Matthias [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Noskov, Yury A. [Institute of Systematics and Ecology of Animals, Russian Academy of Sciences, Siberian Branch, Frunze St. 11, 630091 Novosibirsk (Russian Federation); Schaefer, Ralf B. [Quantitative Landscape Ecology, Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau (Germany); Beketov, Mikhail A., E-mail: mikhail.beketov@ufz.de [Department of System Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany)

2013-02-15

Climate change models predict an increase in the frequency and intensity of extreme fluctuations in water level in aquatic habitats. Therefore, it is necessary to understand the combined effects of hydrological fluctuations and toxicants on aquatic biological communities. We investigated the individual and combined effects of the insecticide esfenvalerate and recurring fluctuations in water level on zooplankton communities in a system of 55 outdoor pond microcosms. The communities were exposed to esfenvalerate contamination as a single pulse (at 0.03, 0.3, or 3 {mu}g/L) and gradual removal of water and its subsequent replacement over three cycles and monitored until 84 days after contamination. The results showed that the sensitivities of the community and its constituent populations to the toxicant were increased by the hydrological stress. Specifically, for both the community structure and abundance of Daphnia spp. the lowest-observed-effect concentrations (LOEC) were 0.03 and 0.3 {mu}g/L for the series with fluctuating and constant water levels, respectively. Despite these differences in sensitivity, the interactive effects of the two stressors were found to be additive for both the community structure and the abundance of the most affected species. Presumably, it was not possible to detect synergism due to the strong individual effects of the water level fluctuations. Recovery times in the series exposed to the highest pesticide concentration were 64 and 55 days under fluctuating and constant water level regimes, respectively. Competition and water quality are suggested to be the major factors that underlie the observed effects of fluctuations in the water level. For the ecological risk assessment of toxicants, the present results suggest that (i) community sensitivity may vary substantially, depending on the environmental context, and (ii) this variability can be assessed experimentally to derive safety factors (coefficients used to avoid unexpected effects

Microalgal cell disruption via ultrasonic nozzle spraying.

Science.gov (United States)

Wang, M; Yuan, W

2015-01-01

The objective of this study was to understand the effect of operating parameters, including ultrasound amplitude, spraying pressure, nozzle orifice diameter, and initial cell concentration on microalgal cell disruption and lipid extraction in an ultrasonic nozzle spraying system (UNSS). Two algal species including Scenedesmus dimorphus and Nannochloropsis oculata were evaluated. Experimental results demonstrated that the UNSS was effective in the disruption of microalgal cells indicated by significant changes in cell concentration and Nile red-stained lipid fluorescence density between all treatments and the control. It was found that increasing ultrasound amplitude generally enhanced cell disruption and lipid recovery although excessive input energy was not necessary for best results. The effect of spraying pressure and nozzle orifice diameter on cell disruption and lipid recovery was believed to be dependent on the competition between ultrasound-induced cavitation and spraying-generated shear forces. Optimal cell disruption was not always achieved at the highest spraying pressure or biggest nozzle orifice diameter; instead, they appeared at moderate levels depending on the algal strain and specific settings. Increasing initial algal cell concentration significantly reduced cell disruption efficiency. In all UNSS treatments, the effectiveness of cell disruption and lipid recovery was found to be dependent on the algal species treated.

Applications of Microalgal Biotechnology for Disease Control in Aquaculture

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Patai Charoonnart

2018-04-01

Full Text Available Aquaculture industries, and in particular the farming of fish and crustaceans, are major contributors to the economy of many countries and an increasingly important component in global food supply. However, the severe impact of aquatic microbial diseases on production performance remains a challenge to these industries. This article considers the potential applications of microalgal technology in the control of such diseases. At the simplest level, microalgae offer health-promoting benefits as a nutritional supplement in feed meal because of their digestibility and high content of proteins, lipids and essential nutrients. Furthermore, some microalgal species possess natural anti-microbial compounds or contain biomolecules that can serve as immunostimulants. In addition, emerging genetic engineering technologies in microalgae offer the possibility of producing ‘functional feed additives’ in which novel and specific bioactives, such as fish growth hormones, anti-bacterials, subunit vaccines, and virus-targeted interfering RNAs, are components of the algal supplement. The evaluation of such technologies for farm applications is an important step in the future development of sustainable aquaculture.

Role of granular activated carbon in the microalgal cultivation from bacteria contamination.

Science.gov (United States)

Ni, Zhi-Yi; Li, Jing-Ya; Xiong, Zhao-Zhao; Cheng, Li-Hua; Xu, Xin-Hua

2018-01-01

Microalgal wastewater treatment has been considered as one of the most promising measures to treat nitrogen and phosphorus in the municipal wastewater. While the municipal wastewater provides sufficient nitrogen and phosphorus for microalgal growth, the microalgae still faces serious biological contamination caused by bacteria in wastewater. In this study, the commercial granular activated carbon (GAC) was added into the simulated municipal wastewater to avoid the influence of bacteria on the growth of microalgae. The extracellular organic matter (EOM) in microalgal broth was then characterized to enlighten the role of GAC in reducing the bioavailability of EOM. The results showed that the GAC addition could increase the dry weight of microalgae from 0.06mgL -1 to 0.46mgL -1 under the condition of bacterial inoculation. The GAC could mitigate bacterial contamination mainly due to its adsorption of both bacteria and EOM that might contain algicidal extracellular substances. Moreover, compared to the control group, the GAC addition could mitigate the microalgal lysis caused by bacteria and thus greatly reduce the bioavailability of EOM from 2.80mgL -1 to 0.61mgL -1 , which was beneficial for the improvement of biostability and reuse of effluent after the microalgal harvesting. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of an industrial microalgal strain for starch production in biorefinery context

NARCIS (Netherlands)

Gifuni, Imma; Olivieri, Giuseppe; Pollio, Antonino; Marzocchella, Antonio

2018-01-01

The recent trends in microalgal cultures are focused on the biorefinery of the biomass components. Some of them are not completely valorised, for example starch. Since there is a wide market for starch products in food and non-food industries, the exploitation of microalgal starch fractions could

Microalgal Cultivation in Secondary Effluent: Recent Developments and Future Work

Directory of Open Access Journals (Sweden)

Junping Lv

2017-01-01

Full Text Available Eutrophication of water catchments and the greenhouse effect are major challenges in developing the global economy in the near future. Secondary effluents, containing high amounts of nitrogen and phosphorus, need further treatment before being discharged into receiving water bodies. At the same time, new environmentally friendly energy sources need to be developed. Integrating microalgal cultivation for the production of biodiesel feedstock with the treatment of secondary effluent is one way of addressing both issues. This article provides a comprehensive review of the latest progress in microalgal cultivation in secondary effluent to remove pollutants and accumulate lipids. Researchers have discovered that microalgae remove nitrogen and phosphorus effectively from secondary effluent, accumulating biomass and lipids in the process. Immobilization of appropriate microalgae, and establishing a consortium of microalgae and/or bacteria, were both found to be feasible ways to enhance pollutant removal and lipid production. Demonstrations of pilot-scale microalgal cultures in secondary effluent have also taken place. However there is still much work to be done in improving pollutants removal, biomass production, and lipid accumulation in secondary effluent. This includes screening microalgae, constructing the consortium, making use of flue gas and nitrogen, developing technologies related to microalgal harvesting, and using lipid-extracted algal residues (LEA.

Qualitative Analysis of Microbial Dynamics during Anaerobic Digestion of Microalgal Biomass in a UASB Reactor

Directory of Open Access Journals (Sweden)

Anna Doloman

2017-01-01

Full Text Available Anaerobic digestion (AD is a microbiologically coordinated process with dynamic relationships between bacterial players. Current understanding of dynamic changes in the bacterial composition during the AD process is incomplete. The objective of this research was to assess changes in bacterial community composition that coordinates with anaerobic codigestion of microalgal biomass cultivated on municipal wastewater. An upflow anaerobic sludge blanket reactor was used to achieve high rates of microalgae decomposition and biogas production. Samples of the sludge were collected throughout AD and extracted DNA was subjected to next-generation sequencing using methanogen mcrA gene specific and universal bacterial primers. Analysis of the data revealed that samples taken at different stages of AD had varying bacterial composition. A group consisting of Bacteroidales, Pseudomonadales, and Enterobacteriales was identified to be putatively responsible for the hydrolysis of microalgal biomass. The methanogenesis phase was dominated by Methanosarcina mazei. Results of observed changes in the composition of microbial communities during AD can be used as a road map to stimulate key bacterial species identified at each phase of AD to increase yield of biogas and rate of substrate decomposition. This research demonstrates a successful exploitation of methane production from microalgae without any biomass pretreatment.

Qualitative Analysis of Microbial Dynamics during Anaerobic Digestion of Microalgal Biomass in a UASB Reactor

Science.gov (United States)

Doloman, Anna; Soboh, Yousef; Walters, Andrew J.; Sims, Ronald C.

2017-01-01

Anaerobic digestion (AD) is a microbiologically coordinated process with dynamic relationships between bacterial players. Current understanding of dynamic changes in the bacterial composition during the AD process is incomplete. The objective of this research was to assess changes in bacterial community composition that coordinates with anaerobic codigestion of microalgal biomass cultivated on municipal wastewater. An upflow anaerobic sludge blanket reactor was used to achieve high rates of microalgae decomposition and biogas production. Samples of the sludge were collected throughout AD and extracted DNA was subjected to next-generation sequencing using methanogen mcrA gene specific and universal bacterial primers. Analysis of the data revealed that samples taken at different stages of AD had varying bacterial composition. A group consisting of Bacteroidales, Pseudomonadales, and Enterobacteriales was identified to be putatively responsible for the hydrolysis of microalgal biomass. The methanogenesis phase was dominated by Methanosarcina mazei. Results of observed changes in the composition of microbial communities during AD can be used as a road map to stimulate key bacterial species identified at each phase of AD to increase yield of biogas and rate of substrate decomposition. This research demonstrates a successful exploitation of methane production from microalgae without any biomass pretreatment. PMID:29259629

Light requirements in microalgal photobioreactors. An overview of biophotonic aspects

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Ana P. [Universidade Catolica Portuguesa, Porto (Portugal). CBQF/Escola Superior de Biotecnologia; Silva, Susana O. [Universidade Catolica Portuguesa, Porto (Portugal). CBQF/Escola Superior de Biotecnologia; INESC Porto, Porto (Portugal); Baptista, Jose M. [INESC Porto, Porto (Portugal); Universidade da Madeira, Funchal (Portugal). Centro de Competencia de Ciencias Exactas e de Engenharia; Malcata, F. Xavier [ISMAI - Instituto Superior da Maia, Avioso S. Pedro (Portugal); Universidade Nova de Lisboa, Oeiras (Portugal). Inst. de Tecnologia Quimica e Biologica

2011-03-15

In order to enhance microalgal growth in photobioreactors (PBRs), light requirement is one of the most important parameters to be addressed; light should indeed be provided at the appropriate intensity, duration, and wavelength. Excessive intensity may lead to photo-oxidation and -inhibition, whereas low light levels will become growth-limiting. The constraint of light saturation may be overcome via either of two approaches: increasing photosynthetic efficiency by genetic engineering, aimed at changing the chlorophyll antenna size; or increasing flux tolerance, via tailoring the photonic spectrum, coupled with its intensity and temporal characteristics. These approaches will allow an increased control over the illumination features, leading to maximization of microalgal biomass and metabolite productivity. This minireview briefly introduces the nature of light, and describes its harvesting and transformation by microalgae, as well as its metabolic effects under excessively low or high supply. Optimization of the photosynthetic efficiency is discussed under the two approaches referred to above; the selection of light sources, coupled with recent improvements in light handling by PBRs, are chronologically reviewed and critically compared. (orig.)

Dynamics of microalgal communities in the water-column/sediment interface of the inner shelf off Parana State, Southern Brazil

Directory of Open Access Journals (Sweden)

Ricardo Luiz Queiroz

2004-12-01

Full Text Available The composition and biomass of the microalgal community at the water-column/sediment interface on the continental shelf off Parana State (Brazil were studied every 2 months during 1999. Samples for cell identification and determination of chlorophyll a were taken from the interface layer and at discrete depths up to 4 m above the sediment. Results showed a community mainly formed by benthic and planktonic diatoms >30 µm, benthic diatoms 30 µm, which accounted for most of the pigment biomass, were resuspended from the interface after turbulent periods, and may take advantage of calm periods to stay and grow at the interface. Small benthic diatoms were more susceptible to wind-induced turbulence occurring in higher densities in the water column just above the water-sediment interface. A cyanobacterial bloom (Trichodesmiun was observed at these bottom layers in the spring-summer periods.A composição geral e a biomassa da comunidade microalgal da interface sedimento/água da plataforma do Estado do Paraná (Brasil foram estudadas em 1999 em relação ao regime de ventos. A cada dois meses foram coletadas amostras para a identificação de organismos e determinação de clorofila a, na interface água-sedimento e em profundidades discretas, ao longo da coluna d'água, até 4m acima do sedimento. Os resultados obtidos revelaram uma comunidade constituída principalmente por diatomáceas planctônicas e bentônicas maiores que 30 µm, diatomáceas bentônicas menores que 30 µm, e cianobactérias coloniais. As densidades celulares foram geralmente mais altas na interface. Eventos de mistura e sedimentação parecem ser determinantes na regulação da composição e biomassa de tais comunidades. Formas menores, mais susceptíveis à turbulência, dominaram a comunidade de água de fundo na maioria das ocasiões, e foram as mais abundantes na interface apenas em períodos de extrema estabilidade. Células maiores, aparentemente contendo a maior parte

The effect of light supply on microalgal growth, CO2 uptake and nutrient removal from wastewater

International Nuclear Information System (INIS)

Gonçalves, A.L.; Simões, M.; Pires, J.C.M.

2014-01-01

Highlights: • Effect of irradiance and light:dark ratio on microalgal growth was analysed. • Microalgal growth, CO 2 capture, nitrogen and phosphorus uptake were evaluated. • Higher irradiances and light periods supported higher growth and CO 2 uptake rates. • All the studied microalgal strains have shown high nitrogen removal efficiencies. • The highest phosphorus removal efficiency was 67.6%. - Abstract: Microalgal based biofuels have been reported as an attractive alternative for fossil fuels, since they constitute a renewable energy source that reduces greenhouse gas emissions to the atmosphere. However, producing biofuels from microalgae is still not economically viable. Therefore, the integration of biofuel production with other microalgal applications, such as CO 2 capture and nutrient removal from wastewaters, would reduce the microalgal production costs (and the environmental impact of cultures), increasing the economic viability of the whole process. Additionally, producing biofuels from microalgae strongly depends on microalgal strain and culture conditions. This study evaluates the effect of culture conditions, namely light irradiance (36, 60, 120 and 180 μE m −2 s −1 ) and light:dark ratio (10:14, 14:10 and 24:0), on microalgal growth, atmospheric CO 2 uptake and nutrient (nitrogen and phosphorous) removal from culture medium. Four different microalgal strains, Chlorella vulgaris, Pseudokirchneriella subcapitata, Synechocystis salina and Microcystis aeruginosa, were studied to ascertain the most advantageous regarding the referred applications. This study has shown that higher light irradiance values and light periods resulted in higher specific growth rates and CO 2 uptake rates. C. vulgaris presented the highest specific growth rate and CO 2 uptake rate: 1.190 ± 0.041 d −1 and 0.471 ± 0.047 g CO2 L −1 d −1 , respectively. All the strains have shown high nitrogen removal efficiencies, reaching 100% removal percentages in

Low-level toxicity of chemicals: No acceptable levels?

Directory of Open Access Journals (Sweden)

Bruce P Lanphear

2017-12-01

Full Text Available Over the past 3 decades, in a series of studies on some of the most extensively studied toxic chemicals and pollutants, scientists have found that the amount of toxic chemical linked with the development of a disease or death-which is central to determining "safe" or "hazardous" levels-is proportionately greater at the lowest dose or levels of exposure. These results, which are contrary to the way the United States Environmental Protection Agency (EPA and other regulatory agencies assess the risk of chemicals, indicate that we have underestimated the impact of toxic chemicals on death and disease. If widely disseminated chemicals and pollutants-like radon, lead, airborne particles, asbestos, tobacco, and benzene-do not exhibit a threshold and are proportionately more toxic at the lowest levels of exposure, we will need to achieve near-zero exposures to protect public health.

An indicator for effects of organic toxicants on lotic invertebrate communities: Independence of confounding environmental factors over an extensive river continuum

International Nuclear Information System (INIS)

Beketov, Mikhail A.; Liess, Matthias

2008-01-01

Distinguishing between effects of natural and anthropogenic environmental factors on ecosystems is a fundamental problem in environmental science. In river systems the longitudinal gradient of environmental factors is one of the most relevant sources of dissimilarity between communities that could be confounded with anthropogenic disturbances. To test the hypothesis that in macroinvertebrate communities the distribution of species' sensitivity to organic toxicants is independent of natural longitudinal factors, but depends on contamination with organic toxicants, we analysed the relationship between community sensitivity SPEAR organic (average community sensitivity to organic toxicants) and natural and anthropogenic environmental factors in a large-scale river system, from alpine streams to a lowland river. The results show that SPEAR organic is largely independent of natural longitudinal factors, but strongly dependent on contamination with organic toxicants (petrochemicals and synthetic surfactants). Usage of SPEAR organic as a stressor-specific longitude-independent measure will facilitate detection of community disturbance by organic toxicants. - Indicator for organic toxicants at community level can be independent of natural environmental factors

Towards microalgal triglycerides in the commodity markets

NARCIS (Netherlands)

Benvenuti, Giulia; Ruiz, Jesús; Lamers, Packo P.; Bosma, Rouke; Wijffels, René H.; Barbosa, Maria J.

2017-01-01

Background: Microalgal triglycerides (TAGs) hold great promise as sustainable feedstock for commodity industries. However, to determine research priorities and support business decisions, solid techno-economic studies are essential. Here, we present a techno-economic analysis of two-step TAG

Kinetics of Chlorella protothecoides microalgal oil using base catalyst

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Mukesh Kumar

2016-09-01

Full Text Available Due to continuous diminishing of fossil fuel resources and emission of greenhouse gases, the search for alternative fuels such as biodiesel and bioethanol has become inevitable. Biodiesel, also known as fatty acid methyl or ethyl ester, has emerged as a substitute for diesel because of similar fuel properties. Presently, biodiesel is produced from edible, non-edible and microalgal oil. Chlorella protothecoides (lipid content 14.6–57.8% is being investigated as the potential microalgae species owing to high oil content, less land area required for cultivation and faster growth rate. The present investigation shows the results of the kinetics of transesterification of C. protothecoides microalgal oil carried out at optimum conditions of catalyst concentration, reaction temperature, molar ratio and reaction time. The percentage of methyl ester yield is the only parameter chosen to carry out the optimum parameter and the kinetics of transesterification. The reaction rate constant was to be 0.0618 min−1. Furthermore, microalgal biodiesel is characterized for physico-chemical properties that are found to meet American (ASTM D6751 and Indian (IS 15607 standards, especially in cold flow properties and stability of conventional biodiesel.

Progress and Challenges in Microalgal Biodiesel Production

Science.gov (United States)

Mallick, Nirupama; Bagchi, Sourav K.; Koley, Shankha; Singh, Akhilesh K.

2016-01-01

The last decade has witnessed a tremendous impetus on biofuel research due to the irreversible diminution of fossil fuel reserves for enormous demands of transportation vis-a-vis escalating emissions of green house gasses (GHGs) into the atmosphere. With an imperative need of CO2 reduction and considering the declining status of crude oil, governments in various countries have not only diverted substantial funds for biofuel projects but also have introduced incentives to vendors that produce biofuels. Currently, biodiesel production from microalgal biomass has drawn an immense importance with the potential to exclude high-quality agricultural land use and food safe-keeping issues. Moreover, microalgae can grow in seawater or wastewater and microalgal oil can exceed 50–60% (dry cell weight) as compared with some best agricultural oil crops of only 5–10% oil content. Globally, microalgae are the highest biomass producers and neutral lipid accumulators contending any other terrestrial oil crops. However, there remain many hurdles in each and every step, starting from strain selection and lipid accumulation/yield, algae mass cultivation followed by the downstream processes such as harvesting, drying, oil extraction, and biodiesel conversion (transesterification), and overall, the cost of production. Isolation and screening of oleaginous microalgae is one pivotal important upstream factor which should be addressed according to the need of freshwater or marine algae with a consideration that wild-type indigenous isolate can be the best suited for the laboratory to large scale exploitation. Nowadays, a large number of literature on microalgal biodiesel production are available, but none of those illustrate a detailed step-wise description with the pros and cons of the upstream and downstream processes of biodiesel production from microalgae. Specifically, harvesting and drying constitute more than 50% of the total production costs; however, there are quite a less

Phytoplankton-Associated Bacterial Community Composition and Succession during Toxic Diatom Bloom and Non-Bloom Events.

Science.gov (United States)

Sison-Mangus, Marilou P; Jiang, Sunny; Kudela, Raphael M; Mehic, Sanjin

2016-01-01

Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting. Opportunistic sampling of bacterial community profiles were determined weekly at Santa Cruz Municipal Wharf by 454 pyrosequencing and analyzed together with domoic acid levels, phytoplankton community and biomass, nutrients and temperature. We asked if the bacterial communities are similar between bloom and non-bloom events and if domoic acid or the presence of toxic algal species acts as a driving force that can significantly structure phytoplankton-associated bacterial communities. We found that bacterial diversity generally increases when Pseudo-nitzschia numbers decline. Furthermore, bacterial diversity is higher when the low-DA producing P. fraudulenta dominates the algal bloom while bacterial diversity is lower when high-DA producing P. australis dominates the algal bloom, suggesting that the presence of algal toxin can structure bacterial community. We also found bloom-related succession patterns among associated bacterial groups; Gamma-proteobacteria, were dominant during low toxic P. fraudulenta blooms comprising mostly of Vibrio spp., which increased in relative abundance (6-65%) as the bloom progresses. On the other hand, Firmicutes bacteria comprising mostly of Planococcus spp. (12-86%) dominate during high toxic P. australis blooms, with the bacterial assemblage showing the same bloom-related successional patterns in three independent bloom events. Other environmental

Phytoplankton-associated bacterial community composition and succession during toxic diatom bloom and non-bloom events

Directory of Open Access Journals (Sweden)

Marilou P. Sison-Mangus

2016-09-01

Full Text Available Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting. Opportunistic sampling of bacterial community profiles were determined weekly at Santa Cruz Municipal Wharf by 454 pyrosequencing and analyzed together with domoic acid levels, phytoplankton community and biomass, nutrients and temperature. We asked if the bacterial communities are similar between bloom and non-bloom events and if domoic acid or the presence of toxic algal species acts as a driving force that can significantly structure phytoplankton-associated bacterial communities. We found that bacterial diversity generally increases when Pseudo-nitzschia numbers decline. Furthermore, bacterial diversity is higher when the low-DA producing P. fraudulenta dominates the algal bloom while bacterial diversity is lower when high-DA producing P. australis dominates the algal bloom, suggesting that the presence of algal toxin can structure bacterial community. We also found bloom-related succession patterns among associated bacterial groups; Gamma-proteobacteria, were dominant during low toxic P. fraudulenta blooms comprising mostly of Vibrio spp., which increased in relative abundance (6%-65% as the bloom progresses. On the other hand, Firmicutes bacteria comprising mostly of Planococcus spp. (12%- 86% dominate during high toxic P. australis blooms, with the bacterial assemblage showing the same bloom-related successional patterns in 3 independent bloom events. Other

Physico-chemical and biotic factors influencing microalgal seed ...

African Journals Online (AJOL)

Physico-chemical and biotic factors influencing microalgal seed culture propagation for inoculation of a ... African Journal of Biotechnology ... used to inoculate an open raceway pond for large scale biomass production for biodiesel production.

Treatment of cattle-slaughterhouse wastewater and the reuse of sludge for biodiesel production by microalgal heterotrophic bioreactors

Directory of Open Access Journals (Sweden)

Mariana Manzoni Maroneze

2014-12-01

Full Text Available Microalgal heterotrophic bioreactors are a potential technological development that can convert organic matter, nitrogen and phosphorus of wastewaters into a biomass suitable for energy production. The aim of this work was to evaluate the performance of microalgal heterotrophic bioreactors in the secondary treatment of cattle-slaughterhouse wastewater and the reuse of microalgal sludge for biodiesel production. The experiments were performed in a bubble column bioreactor using the microalgae Phormidium sp. Heterotrophic microalgal bioreactors removed 90 % of the chemical oxygen demand, 57 % of total nitrogen and 52 % of total phosphorus. Substantial microalgal sludge is produced in the process (substrate yield coefficient of 0.43 mg sludge mg chemical oxygen demand−¹, resulting in a biomass with high potential for producing biodiesel (ester content of more than 99 %, cetane number of 55, iodine value of 73.5 g iodine 100 g−¹, unsaturation degree of ~75 % and a cold filter plugging point of 5 ºC.

A simple, reproducible and sensitive spectrophotometric method to estimate microalgal lipids

Energy Technology Data Exchange (ETDEWEB)

Chen Yimin [ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Vaidyanathan, Seetharaman, E-mail: s.vaidyanathan@sheffield.ac.uk [ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

2012-04-29

Highlights: Black-Right-Pointing-Pointer FAs released from lipids form complex with Cu-TEA in chloroform. Black-Right-Pointing-Pointer The FA-Cu-TEA complex gives strong absorbance at 260 nm. Black-Right-Pointing-Pointer The absorbance is sensitive and independent of C-atom number in the FAs (10-18). Black-Right-Pointing-Pointer Microalgal lipid extract and pure FA (such as C16) can both be used as standards. - Abstract: Quantification of total lipids is a necessity for any study of lipid production by microalgae, especially given the current interest in microalgal carbon capture and biofuels. In this study, we employed a simple yet sensitive method to indirectly measure the lipids in microalgae by measuring the fatty acids (FA) after saponification. The fatty acids were reacted with triethanolamine-copper salts (TEA-Cu) and the ternary TEA-Cu-FA complex was detected at 260 nm using a UV-visible spectrometer without any colour developer. The results showed that this method could be used to analyse low levels of lipids in the range of nano-moles from as little as 1 mL of microalgal culture. Furthermore, the structure of the TEA-Cu-FA complex and related reaction process are proposed to better understand this assay. There is no special instrument required and the method is very reproducible. To the best of our knowledge, this is the first report of the use of UV absorbance of copper salts with FA as a method to estimate lipids in algal cultures. It will pave the way for a more convenient assay of lipids in microalgae and can readily be expanded for estimating lipids in other biological systems.

A simple, reproducible and sensitive spectrophotometric method to estimate microalgal lipids

International Nuclear Information System (INIS)

Chen Yimin; Vaidyanathan, Seetharaman

2012-01-01

Highlights: ► FAs released from lipids form complex with Cu–TEA in chloroform. ► The FA–Cu–TEA complex gives strong absorbance at 260 nm. ► The absorbance is sensitive and independent of C-atom number in the FAs (10–18). ► Microalgal lipid extract and pure FA (such as C16) can both be used as standards. - Abstract: Quantification of total lipids is a necessity for any study of lipid production by microalgae, especially given the current interest in microalgal carbon capture and biofuels. In this study, we employed a simple yet sensitive method to indirectly measure the lipids in microalgae by measuring the fatty acids (FA) after saponification. The fatty acids were reacted with triethanolamine–copper salts (TEA–Cu) and the ternary TEA–Cu–FA complex was detected at 260 nm using a UV–visible spectrometer without any colour developer. The results showed that this method could be used to analyse low levels of lipids in the range of nano-moles from as little as 1 mL of microalgal culture. Furthermore, the structure of the TEA–Cu–FA complex and related reaction process are proposed to better understand this assay. There is no special instrument required and the method is very reproducible. To the best of our knowledge, this is the first report of the use of UV absorbance of copper salts with FA as a method to estimate lipids in algal cultures. It will pave the way for a more convenient assay of lipids in microalgae and can readily be expanded for estimating lipids in other biological systems.

Harvesting Microalgal Biomass grown in Anaerobic Sewage Treatment Effluent by the Coagulation-Flocculation Method: Effect of pH

Directory of Open Access Journals (Sweden)

Servio Tulio Cassini

2017-03-01

Full Text Available ABSTRACT Harvesting is a critical step in microalgal biomass production process for many reasons. Among the existing techniques available for harvesting and dewatering microalgal biomass, recovery from aqueous medium by coagulation-flocculation has been the most economically viable process, althoughit is highly dependent on pH. This study aims to assess alternative coagulants compared to the standard coagulant aluminum sulfate for microalgal biomass recovery from anaerobic effluent of domestic sewage treatment. The effluent quality was also analyzed after biomass recovery. Coagulants represented by modified tannin, cationic starch and aluminum sulfate recovered more than 90% of algae biomass, at concentrations greater than 80 mg/L, in the pH range 7-10. Cationic starch promoted higher microalgal biomass recovery with a wider pH range. Powdered seeds of Moringa oleifera and Hibiscus esculentus(okra gum promoted biomass removal of 50%, only in the acidic range of pH. After sedimentation of the microalgal biomass, the effluents showed a removal of >80% for phosphorus and nitrogen values and >50% for BOD and COD when using aluminum sulfate, cationic starch and modified tannin as coagulants. Natural organic coagulants in a wide pH range can replace aluminum sulfate, a reference coagulant in microalgal biomass recovery, without decreasing microalgal biomass harvesting efficiency and the quality of the final effluent.

Toxicity of diesel water accommodated fraction toward microalgae, Pseudokirchneriella subcapitata and Chlorella sp. MM3.

Science.gov (United States)

Ramadass, Kavitha; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

2017-08-01

Diesel is a commonly used fuel and a key pollutant on water surface through leaks and accidental spills, thus creating risk directly to planktons as well as other aquatic organisms. We assessed the toxicty of diesel and its water accommodated fraction (WAF) towards two microalgal species, Pseudokirchneriella subcapitata and Chlorella sp. MM3. The toxicity criteria included were: chlorophyll a content as a growth parameter and induction of enzyme activities linked to oxidative stress. Increase in concentrations of diesel or its WAF significantly increased toxicity towards growth, measured in terms of chlorophyll a content in both the algae. Activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in response to addition of diesel or diesel WAF to the microalgal cultures were dose-dependent. Diesel WAF was more toxic than diesel itself, suggesting that use of WAF may be more relevant for environmental risk assessment of diesel. The overall response of the antioxidant enzymes to toxicants' stress followed the order: POX≥SOD>CAT. The present study clearly demonstrated the use of SOD, POX and CAT as suitable biomarkers for assessing diesel pollution in aquatic ecosystem. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiology limits commercially viable photoautotrophic production of microalgal biofuels.

Science.gov (United States)

Kenny, Philip; Flynn, Kevin J

2017-01-01

Algal biofuels have been offered as an alternative to fossil fuels, based on claims that microalgae can provide a highly productive source of compounds as feedstocks for sustainable transport fuels. Life cycle analyses identify algal productivity as a critical factor affecting commercial and environmental viability. Here, we use mechanistic modelling of the biological processes driving microalgal growth to explore optimal production scenarios in an industrial setting, enabling us to quantify limits to algal biofuels potential. We demonstrate how physiological and operational trade-offs combine to restrict the potential for solar-powered algal-biodiesel production in open ponds to a ceiling of ca. 8000 L ha -1 year -1 . For industrial-scale operations, practical considerations limit production to ca. 6000 L ha -1 year -1 . According to published economic models and life cycle analyses, such production rates cannot support long-term viable commercialisation of solar-powered cultivation of natural microalgae strains exclusively as feedstock for biofuels. The commercial viability of microalgal biofuels depends critically upon limitations in microalgal physiology (primarily in rates of C-fixation); we discuss the scope for addressing this bottleneck concluding that even deployment of genetically modified microalgae with radically enhanced characteristics would leave a very significant logistical if not financial burden.

Ecotoxicological effects of enrofloxacin and its removal by monoculture of microalgal species and their consortium.

Science.gov (United States)

Xiong, Jiu-Qiang; Kurade, Mayur B; Jeon, Byong-Hun

2017-07-01

Enrofloxacin (ENR), a fluoroquinolone antibiotic, has gained big scientific concern due to its ecotoxicity on aquatic microbiota. The ecotoxicity and removal of ENR by five individual microalgae species and their consortium were studied to correlate the behavior and interaction of ENR in natural systems. The individual microalgal species (Scenedesmus obliquus, Chlamydomonas mexicana, Chlorella vulgaris, Ourococcus multisporus, Micractinium resseri) and their consortium could withstand high doses of ENR (≤1 mg L -1 ). Growth inhibition (68-81%) of the individual microalgae species and their consortium was observed in ENR (100 mg L -1 ) compared to control after 11 days of cultivation. The calculated 96 h EC 50 of ENR for individual microalgae species and microalgae consortium was 9.6-15.0 mg ENR L -1 . All the microalgae could recover from the toxicity of high concentrations of ENR during cultivation. The biochemical characteristics (total chlorophyll, carotenoid, and malondialdehyde) were significantly influenced by ENR (1-100 mg L -1 ) stress. The individual microalgae species and microalgae consortium removed 18-26% ENR at day 11. Although the microalgae consortium showed a higher sensitivity (with lower EC 50 ) toward ENR than the individual microalgae species, the removal efficiency of ENR by the constructed microalgae consortium was comparable to that of the most effective microalgal species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of global change-related impacts on the mercury toxicity of freshwater algal communities.

Science.gov (United States)

Val, Jonatan; Muñiz, Selene; Gomà, Joan; Navarro, Enrique

2016-01-01

The climatic-change related increase of temperatures, are expected to alter the distribution and survival of freshwater species, ecosystem functions, and also the effects of toxicants to aquatic biota. This study has thus assessed, as a first time, the modulating effect of climate-change drivers on the mercury (Hg) toxicity of freshwater algal photosynthesis. Natural benthic algal communities (periphyton) have been exposed to Hg under present and future temperature scenarios (rise of 5 °C). The modulating effect of other factors (also altered by global change), as the quality and amount of suspended and dissolved materials in the rivers, has been also assessed, exposing algae to Hg in natural river water or a synthetic medium. The EC50 values ranged from the 0.15-0.74 ppm for the most sensitive communities, to the 24-40 ppm for the most tolerant. The higher tolerance shown by communities exposed to higher Hg concentrations, as Jabarrella was in agreement with the Pollution Induced Community Tolerance concept. In other cases, the dominance of the invasive diatom Didymosphenia geminata explained the tolerance or sensitivity of the community to the Hg toxicity. Results shown that while increases in the suspended solids reduced Hg bioavailability, changes in the dissolved materials - such as organic carbon - may increase it and thus its toxic effects on biota. The impacts of the increase of temperatures on the toxicological behaviour of periphyton (combining both changes at species composition and physiological acclimation) would be certainly modulated by other effects at the land level (i.e., alterations in the amount and quality of dissolved and particulate substances arriving to the rivers). Copyright © 2015 Elsevier B.V. All rights reserved.

Calculating background levels for ecological risk parameters in toxic harbor sediment

Science.gov (United States)

Leadon, C.J.; McDonnell, T.R.; Lear, J.; Barclift, D.

2007-01-01

Establishing background levels for biological parameters is necessary in assessing the ecological risks from harbor sediment contaminated with toxic chemicals. For chemicals in sediment, the term contaminated is defined as having concentrations above background and significant human health or ecological risk levels. For biological parameters, a site could be considered contaminated if levels of the parameter are either more or less than the background level, depending on the specific parameter. Biological parameters can include tissue chemical concentrations in ecological receptors, bioassay responses, bioaccumulation levels, and benthic community metrics. Chemical parameters can include sediment concentrations of a variety of potentially toxic chemicals. Indirectly, contaminated harbor sediment can impact shellfish, fish, birds, and marine mammals, and human populations. This paper summarizes the methods used to define background levels for chemical and biological parameters from a survey of ecological risk investigations of marine harbor sediment at California Navy bases. Background levels for regional biological indices used to quantify ecological risks for benthic communities are also described. Generally, background stations are positioned in relatively clean areas exhibiting the same physical and general chemical characteristics as nearby areas with contaminated harbor sediment. The number of background stations and the number of sample replicates per background station depend on the statistical design of the sediment ecological risk investigation, developed through the data quality objective (DQO) process. Biological data from the background stations can be compared to data from a contaminated site by using minimum or maximum background levels or comparative statistics. In Navy ecological risk assessments (ERA's), calculated background levels and appropriate ecological risk screening criteria are used to identify sampling stations and sites with contaminated

Regulations for marine microalgal toxins: Towards harmonization of ...

African Journals Online (AJOL)

The World Trade Organization and the General Agreements on Tariffs and Trade encourage the harmonization of regulations on food safety requirements. The current policy on trade liberalization of seafood is presented, together with a review of the regulations for marine microalgal toxins. Activities on harmonization of ...

Linking ‘toxic outliers’ to environmental justice communities

International Nuclear Information System (INIS)

Collins, Mary B; Munoz, Ian; JaJa, Joseph

2016-01-01

Several key studies have found that a small minority of producers, polluting at levels far exceeding group averages, generate the majority of overall exposure to industrial toxics. Frequently, such patterns go unnoticed and are understudied outside of the academic community. To our knowledge, no research to date has systematically described the scope and extent of extreme variations in industrially based exposure estimates and sought to link inequities in harm produced to inequities in exposure. In an analysis of all permitted industrial facilities across the United States, we show that there exists a class of hyper-polluters—the worst-of-the-worst—that disproportionately expose communities of color and low income populations to chemical releases. This study hopes to move beyond a traditional environmental justice research frame, bringing new computational methods and perspectives aimed at the empirical study of societal power dynamics. Our findings suggest the possibility that substantial environmental gains may be made through selective environmental enforcement, rather than sweeping initiatives. (letter)

On the use of selective environments in microalgal cultivation

NARCIS (Netherlands)

Mooij, P.R.

2016-01-01

This thesis deals with selective environments in microalgal cultivation. As explained in Chapter 1 microalgae have changed the course of life on Earth dramatically by performing oxygenic photosynthesis. In oxygenic photosynthesis electrons from water are used to reduce carbon dioxide to

Enzymatic transesterification of microalgal oil from Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized Burkholderia lipase.

Science.gov (United States)

Tran, Dang-Thuan; Yeh, Kuei-Ling; Chen, Ching-Lung; Chang, Jo-Shu

2012-03-01

An indigenous microalga Chlorella vulgaris ESP-31 grown in an outdoor tubular photobioreactor with CO(2) aeration obtained a high oil content of up to 63.2%. The microalgal oil was then converted to biodiesel by enzymatic transesterification using an immobilized lipase originating from Burkholderia sp. C20. The conversion of the microalgae oil to biodiesel was conducted by transesterification of the extracted microalgal oil (M-I) and by transesterification directly using disrupted microalgal biomass (M-II). The results show that M-II achieved higher biodiesel conversion (97.3 wt% oil) than M-I (72.1 wt% oil). The immobilized lipase worked well when using wet microalgal biomass (up to 71% water content) as the oil substrate. The immobilized lipase also tolerated a high methanol to oil molar ratio (>67.93) when using the M-II approach, and can be repeatedly used for six cycles (or 288 h) without significant loss of its original activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Optimal processing pathway for the production of biodiesel from microalgal biomass: A superstructure based approach

DEFF Research Database (Denmark)

Rizwan, Muhammad; Lee, Jay H.; Gani, Rafiqul

2013-01-01

In this study, we propose a mixed integer nonlinear programming (MINLP) model for superstructure based optimization of biodiesel production from microalgal biomass. The proposed superstructure includes a number of major processing steps for the production of biodiesel from microalgal biomass......, such as the harvesting of microalgal biomass, pretreatments including drying and cell disruption of harvested biomass, lipid extraction, transesterification, and post-transesterfication purification. The proposed model is used to find the optimal processing pathway among the large number of potential pathways that exist...... for the production of biodiesel from microalgae. The proposed methodology is tested by implementing on a specific case with different choices of objective functions. The MINLP model is implemented and solved in GAMS using a database built in Excel. The results from the optimization are analyzed...

Succession and physiological health of freshwater microalgal fouling in a Tasmanian hydropower canal.

Science.gov (United States)

Perkins, Kathryn J; Andrewartha, Jessica M; McMinn, Andrew; Cook, Suellen S; Hallegraeff, Gustaaf M

2010-08-01

Freshwater microalgal biofouling in hydropower canals in Tarraleah, Tasmania, is dominated by a single diatom species, Gomphonema tarraleahae. The microfouling community is under investigation with the aim of reducing its impact on electricity generation. Species succession was investigated using removable glass slides. Fouled slides were examined microscopically and for chlorophyll a biomass. Chl a biomass increased steeply after 8 weeks (0.09-0.87 mg m(-2)), but increased much earlier on slides surrounded by a biofouled inoculum. Succession began with low profile diatoms such as Tabellaria flocculosa, progressing to stalked diatoms such as Gomphonema spp. and Cymbella aspera. Few chlorophytes and no filamentous algae were present. Pulse amplitude modulated fluorometry was used to measure the physiological health of fouling on the canal wall. Maximum quantum yield (F(v)/F(m)) measurements were consistently <0.18, indicating that the fouling mat consisted of dead or dying algae. The succession and physiological health of cells in the fouling community has broad implications for mitigation techniques used.

The ecological competition and grazing reverse the effects of sulfamethoxazole on plankton: a case study on characterizing community-level effect.

Science.gov (United States)

Wang, Changyou; Liang, Shengkang; Zhang, Yong

2018-04-12

The toxic effects of sulfamethoxazole (SMX) on densities of two algae, Platymonas helgolandica var. tsingtaoensis, Isochrysis galbana, and of a rotifer, Brachionus plicatilis, were tested by the population and community experiments. Two endpoints, the carrying capacity and the densities array of community in steady state (DACS), were used to characterize the toxic effects at a population level and a community one, respectively. The results showed that the carrying capacity of P. helgolandica var. tsingtaoensis and B. plicatilis did not decline significantly in population test when the concentration of SMX was lower than 6.0 mg L -1 and 12.0 mg L -1 , respectively. However, I. galbana was sensitive to SMX and had presented toxic effect at 3.0 mg L -1 . By extrapolation of toxic effect at a population level to a community one, a derived community-NOEC was 3.0 mg L -1 , representing an inference from data of toxic effects at population level. In community experiment, when the customized community was in steady state, the density of I. galbana increased as a whole with SMX concentration in the range of tested concentration (0-144 mg L -1 ), while that of P. helgolandica var. tsingtaoensis assumed the trend of a reversed "v" in this range. Only the density of B. plicatilis decreased with SMX concentration. With the DACS as endpoint, a NOEC for the customized community was determined to be 6.0 mg L -1 . This indicates that interspecific interactions can reverse the toxic effects of SMX on phytoplankton. The DACS was reliable and stable, serving as the endpoints in assessment of the effects of the pollutants on the ecosystems.

Thermochemical conversion of microalgal biomass into biofuels: a review.

Science.gov (United States)

Chen, Wei-Hsin; Lin, Bo-Jhih; Huang, Ming-Yueh; Chang, Jo-Shu

2015-05-01

Following first-generation and second-generation biofuels produced from food and non-food crops, respectively, algal biomass has become an important feedstock for the production of third-generation biofuels. Microalgal biomass is characterized by rapid growth and high carbon fixing efficiency when they grow. On account of potential of mass production and greenhouse gas uptake, microalgae are promising feedstocks for biofuels development. Thermochemical conversion is an effective process for biofuel production from biomass. The technology mainly includes torrefaction, liquefaction, pyrolysis, and gasification. Through these conversion technologies, solid, liquid, and gaseous biofuels are produced from microalgae for heat and power generation. The liquid bio-oils can further be upgraded for chemicals, while the synthesis gas can be synthesized into liquid fuels. This paper aims to provide a state-of-the-art review of the thermochemical conversion technologies of microalgal biomass into fuels. Detailed conversion processes and their outcome are also addressed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

International Nuclear Information System (INIS)

Halton, D.M.

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC LO , LC 10 and LC 50 levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

Energy Technology Data Exchange (ETDEWEB)

Halton, D M

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC{sub LO}, LC{sub 10} and LC{sub 50} levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs.

Short-term toxicity of hexavalent-chromium to epipsammic diatoms of a microtidal estuary (Río de la Plata): Responses from the individual cell to the community structure

Energy Technology Data Exchange (ETDEWEB)

Licursi, M., E-mail: malena@ilpla.edu.ar; Gómez, N.

2013-06-15

Highlights: •Diatom's nuclear abnormalities were significantly higher as consequence of chromium exposure. •Diatoms and chlorophytes increased in treatment microcosms. •Nitzschia palea proportion increased significantly in the treatment microcosms. -- Abstract: Diatoms are an integral and often dominant component of the benthic microalgal assemblage in estuarine and shallow coastal environments. Different toxic substances discharged into these ecosystems persist in the water, sediments, and biota for long periods. Among these pernicious agents, the toxicity in diatoms by metal is linked to different steps in the transmembrane and internal movements of the toxicant, causing perturbations in the normal structural and functional cellular components. These changes constitute an early, nontaxonomic warning signal that could potentially serve as an indicator of this type of pollution. The aim of this work was to study the environment-reflecting short-term responses at different levels of organization of epipsammic diatoms from the Río de la Plata estuary, Argentina that had been exposed to hexavalent chromium within experimental microcosms. To this end we monitored: (i) changes in the proportion of the diatoms in relation to other algal groups at the biofilm community level; (ii) shifts in species composition at the diatom-assemblage level; (iii) projected changes in the densities of the most representative species at the population level through comparison of relative growth rates and generation times; and (iv) the cytological changes at the cellular and subcellular levels as indicated by the appearance of teratological effects on individuals and nuclear alterations. The epipsammic biofilms were exposed for 96 h to chromium at a concentration similar to that measured in highly impacted sites along the coast (80 μg L{sup −1}). Chromium pollution, at this concentration and short exposure time did not affect the algal biomass and density of these mature

Short-term toxicity of hexavalent-chromium to epipsammic diatoms of a microtidal estuary (Río de la Plata): Responses from the individual cell to the community structure

International Nuclear Information System (INIS)

Licursi, M.; Gómez, N.

2013-01-01

Highlights: •Diatom's nuclear abnormalities were significantly higher as consequence of chromium exposure. •Diatoms and chlorophytes increased in treatment microcosms. •Nitzschia palea proportion increased significantly in the treatment microcosms. -- Abstract: Diatoms are an integral and often dominant component of the benthic microalgal assemblage in estuarine and shallow coastal environments. Different toxic substances discharged into these ecosystems persist in the water, sediments, and biota for long periods. Among these pernicious agents, the toxicity in diatoms by metal is linked to different steps in the transmembrane and internal movements of the toxicant, causing perturbations in the normal structural and functional cellular components. These changes constitute an early, nontaxonomic warning signal that could potentially serve as an indicator of this type of pollution. The aim of this work was to study the environment-reflecting short-term responses at different levels of organization of epipsammic diatoms from the Río de la Plata estuary, Argentina that had been exposed to hexavalent chromium within experimental microcosms. To this end we monitored: (i) changes in the proportion of the diatoms in relation to other algal groups at the biofilm community level; (ii) shifts in species composition at the diatom-assemblage level; (iii) projected changes in the densities of the most representative species at the population level through comparison of relative growth rates and generation times; and (iv) the cytological changes at the cellular and subcellular levels as indicated by the appearance of teratological effects on individuals and nuclear alterations. The epipsammic biofilms were exposed for 96 h to chromium at a concentration similar to that measured in highly impacted sites along the coast (80 μg L −1 ). Chromium pollution, at this concentration and short exposure time did not affect the algal biomass and density of these mature biofilms. The

Effects of Cr III and Pb on the bioaccumulation and toxicity of Cd in tropical periphyton communities: Implications of pulsed metal exposures

International Nuclear Information System (INIS)

Bere, Taurai; Chia, Mathias Ahii; Tundisi, José Galizia

2012-01-01

Metal exposure pattern, timing, frequency, duration, recovery period, metal type and interactions, has obscured effects on periphyton communities in lotic systems. The objective of this study was to investigate the effects of intermittent exposures of Cr III and Pb on Cd toxicity and bioaccumulation in tropical periphyton communities. Natural periphyton communities were transferred to artificial stream chambers and exposed to metal mixtures at different pulse timing, duration, frequency and recovery periods. Chlorophyll a, dry mass and metal accumulation kinetics were recorded. Cr and Pb decrease the toxic effects of Cd on periphyton communities. Periphyton has high Cd, Cr and Pb accumulation capacity. Cr and Pb reduced the levels of Cd sequestrated by periphyton communities. The closer the frequency and duration of the pulse is to a continuous exposure, the greater the effects of the contaminant on periphyton growth and metal bioaccumulation. Light increased toxic and accumulative effects of metals on the periphyton community. - Highlights: ► We investigated toxicity effects of pulsed metal exposures on bioaccumulation and toxicity in periphyton. ► High frequency of short duration pulses has effects equal to long duration exposures. ► Important role of light in modulating metal toxicity on periphyton demonstrated. ► Factors other than magnitude and duration must be considered in water quality criteria. ► Accurate prediction of metal effects on biofilms requires data on effluent variability. - The study highlights the importance of pulse timing, frequency, duration, recovery period and chemical type on aquatic life.

A comparative study: the impact of different lipid extraction methods on current microalgal lipid research

Science.gov (United States)

2014-01-01

Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO2 extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research. PMID:24456581

Microalgal biomass pretreatment for bioethanol production: a review

Directory of Open Access Journals (Sweden)

Jesús Velazquez-Lucio

2018-03-01

Full Text Available Biofuels derived from microalgae biomass have received a great deal of attention owing to their high potentials as sustainable alternatives to fossil fuels. Microalgae have a high capacity of CO2 fixation and depending on their growth conditions, they can accumulate different quantities of lipids, proteins, and carbohydrates. Microalgal biomass can, therefore, represent a rich source of fermentable sugars for third generation bioethanol production. The utilization of microalgal carbohydrates for bioethanol production follows three main stages: i pretreatment, ii saccharification, and iii fermentation. One of the most important stages is the pretreatment, which is carried out to increase the accessibility to intracellular sugars, and thus plays an important role in improving the overall efficiency of the bioethanol production process. Diverse types of pretreatments are currently used including chemical, thermal, mechanical, biological, and their combinations, which can promote cell disruption, facilitate extraction, and result in the modification the structure of carbohydrates as well as the production of fermentable sugars. In this review, the different pretreatments used on microalgae biomass for bioethanol production are presented and discussed. Moreover, the methods used for starch and total carbohydrates quantification in microalgae biomass are also briefly presented and compared.

Toxicity levels to humans during acute exposure to hydrogen fluoride

International Nuclear Information System (INIS)

Halton, D.M.; Dranitsaris, P.; Baynes, C.J.

1984-11-01

A literature review was conducted of the acute toxicity of hydrogen fluoride (HF) with emphasis on the effects of inhalation of gaseous HF. The data and findings of the relevant references were summarized under four categories: animal studies, controlled human studies, community exposure and industrial exposure. These were critically reviewed and then lethal concentration-time relationships were developed for humans, corresponding to LCsub(LO), LCsub(10) and LCsub(50) levels. The effects of age, health and other physiological variables on the sensitivity to HF were discussed, as well as antagonistic and synergistic effects with other substances

On microalgal settlements and the sluggish development of marine biofouling in Port Blair waters, Andamans.

Science.gov (United States)

Eashwar, M; Nallathambi, T; Kuberaraj, K

2008-01-01

Settlement of microalgae was investigated on Perspex, aluminium and zinc coupons immersed in Port Blair Bay waters for over 3 months. Commencement of fouling was exceptionally slow, and few microalgae were found until 14 days. Settlement occurred thereafter, and 47 microalgal species contributed to the fouling. The dominant forms belonged to the genera Navicula and Nitzschia, whereas Coscinodiscus eccentricus, Gyrosigma balticum and Trichodesmium erythraeum also accounted for high proportions of the settlements. The dominance of Nitzschia sigma was particularly marked on zinc coupons, suggesting an ability by the organism to resist toxicity. Settlement of both centric and pennate diatoms was observed in the early and mid periods, and absolute dominance of the pennate diatoms subsequently. The fouling mass was low even after 103 days, and it is speculated that strong ultraviolet radiation might be the prime reason for the sluggish development of marine biofouling in these oceanic island waters.

Exploring the efficacy of wastewater-grown microalgal biomass as a biofertilizer for wheat.

Science.gov (United States)

Renuka, Nirmal; Prasanna, Radha; Sood, Anjuli; Ahluwalia, Amrik S; Bansal, Radhika; Babu, Santosh; Singh, Rajendra; Shivay, Yashbir S; Nain, Lata

2016-04-01

Microalgae possess the ability to grow and glean nutrients from wastewater; such wastewater-grown biomass can be used as a biofertilizer for crops. The present investigation was undertaken to evaluate two formulations (formulation with unicellular microalgae (MC1) and formulation with filamentous microalgae (MC2); T4 and T5, respectively), prepared using wastewater-grown microalgal biomass, as a biofertilizer (after mixing with vermiculite/compost as a carrier) in wheat crop (Triticum aestivum L. HD2967) under controlled conditions. The highest values of available nitrogen (N), phosphorus (P), and potassium (K) in soil and nitrogen-fixing potential were recorded in treatment T5 (75% N + full-dose PK + formulation with filamentous microalgae (MC2). Microbial biomass carbon was significantly enhanced by 31.8-67.0% in both the inoculated treatments over control (recommended dose of fertilizers), with highest values in T4 (75% N + full-dose PK + formulation with unicellular microalgae (MC1)). Both the microalgal formulations significantly increased the N, P, and K content of roots, shoots, and grains, and the highest total N content of 3.56% in grains was observed in treatment T5. At harvest stage, the treatments inoculated with microalgal formulations (T4 and T5) recorded a 7.4-33% increase in plant dry weight and up to 10% in spike weight. The values of 1000-grain weight showed an enhancement of 5.6-8.4%, compared with T1 (recommended doses of fertilizers). A positive correlation was observed between soil nutrient availability at mid crop stage and plant biometrical parameters at harvest stage. This study revealed the promise of such microalgal consortia as a biofertilizer for 25% N savings and improved yields of wheat crop.

2001 Toxic Chemical Release Inventory Emergency Planning and Community Right to Know Act SEC 313

International Nuclear Information System (INIS)

ZALOUDEK, D.E.

2002-01-01

Pursuant to section 313 of the Emergency Planning and Community Right-To-Know Act of 1986 (EPCRA), and Executive Order 13148, Greening the Government Through Leadership in Environmental Management, the US Department of Energy has prepared and submitted a Toxic Chemical Release Inventory for the Hanford Site covering activities performed during calendar year 2001. EPCRA Section 313 requires facilities that manufacture, process, or otherwise use listed toxic chemicals in quantities exceeding established threshold levels to report total annual releases of those chemicals. During calendar year 2001, Hanford Site activities resulted in one chemical used in amounts exceeding an activity threshold. Accordingly, the Hanford Site 2001 Toxic Chemical Release Inventory, DOE/RL-2002-37, includes total annual amount of lead released to the environment, transferred to offsite locations, and otherwise managed as waste

Bioremoval Capacity Of Phenol By Green Micro-Algal And Fungal Species Isolated From Dry Environment

Directory of Open Access Journals (Sweden)

Abdullah T. Al-fawwaz

2015-08-01

Full Text Available Phenol is an organic hazardous pollutant that exerts toxic effects on living cells at relatively at low concentrations. Moreover accumulation of phenol exhibit toxicity towards the biotic components of the environment. Phenol bioremoval is a very useful approach to clean up the residual phenol from the environment. This study aims at isolating green microalgae and fungi from local dry environment to test their ability to remove phenol. Subsequently two green microalgal species have been isolated and identified as Desmodesmus sp. and Chlamydomonas sp.. Also two fungal species have been isolated and identified as Rhizopus sp. and Mucor sp. Phenol bioremoval capacity as well as the effects of some physicochemical factors on the bioremoval process were then studied. These factors include initial phenol concentration contact time and the synergistic effect Desmodesmus sp. and Rhizopus sp. on the bioremoval process. Both microalgae and fungi showed phenol bioremoval capacity. The highest phenol removal percentage among algae was found 75 by Desmodesmus sp. after 25 days at 25 mgL while the highest phenol removal percentage among fungi was found 86 by Rhizopus sp. after 25 days at 100 mgL. Bioremoval of phenol by the consortium Desmodesmus sp. and Rhizopus sp. was found to be 95 at the phenol concentration 25 mgL.

Scenario Analysis of Nutrient Removal from Municipal Wastewater by Microalgal Biofilms

NARCIS (Netherlands)

Boelee, N.C.; Temmink, H.; Janssen, M.; Buisman, C.J.N.; Wijffels, R.H.

2012-01-01

Microalgae can be used for the treatment of municipal wastewater. The application of microalgal biofilms in wastewater treatment systems seems attractive, being able to remove nitrogen, phosphorus and COD from wastewater at a short hydraulic retention time. This study therefore investigates the area

Assessment of environmental stresses for enhanced microalgal biofuel production-an overview

Directory of Open Access Journals (Sweden)

Dan eCheng

2014-07-01

Full Text Available Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.

76 FR 64022 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

Science.gov (United States)

2011-10-17

... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide. SUMMARY: EPA is announcing... (EPCRA) section 313 toxic chemical release reporting requirements for hydrogen sulfide (Chemical...

Microalgal carbohydrates. An overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels

Energy Technology Data Exchange (ETDEWEB)

Markou, Giorgos; Georgakakis, Dimitris [Agricultural Univ. of Athens (Greece). Dept. of Natural Resources Management and Agricultural Engineering; Angelidaki, Irini [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Environmental Engineering

2012-11-15

Microalgal biomass seems to be a promising feedstock for biofuel generation. Microalgae have relative high photosynthetic efficiencies, high growth rates, and some species can thrive in brackish water or seawater and wastewater from the food- and agro-industrial sector. Today, the main interest in research is the cultivation of microalgae for lipids production to generate biodiesel. However, there are several other biological or thermochemical conversion technologies, in which microalgal biomass could be used as substrate. However, the high protein content or the low carbohydrate content of the majority of the microalgal species might be a constraint for their possible use in these technologies. Moreover, in the majority of biomass conversion technologies, carbohydrates are the main substrate for production of biofuels. Nevertheless, microalgae biomass composition could be manipulated by several cultivation techniques, such as nutrient starvation or other stressed environmental conditions, which cause the microalgae to accumulate carbohydrates. This paper attempts to give a general overview of techniques that can be used for increasing the microalgal biomass carbohydrate content. In addition, biomass conversion technologies, related to the conversion of carbohydrates into biofuels are discussed. (orig.)

Assessment of Environmental Stresses for Enhanced Microalgal Biofuel Production – An Overview

International Nuclear Information System (INIS)

Cheng, Dan; He, Qingfang

2014-01-01

Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates) tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.

Assessment of Environmental Stresses for Enhanced Microalgal Biofuel Production – An Overview

Energy Technology Data Exchange (ETDEWEB)

Cheng, Dan, E-mail: dxcheng@ualr.edu; He, Qingfang, E-mail: dxcheng@ualr.edu [Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR (United States)

2014-07-07

Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates) tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.

Aerobic treatment of swine manure to enhance anaerobic digestion and microalgal cultivation.

Science.gov (United States)

Bekoe, Dominic; Wang, Lijun; Zhang, Bo; Scott Todd, Matthew; Shahbazi, Abolghasem

2018-02-01

Aerobic treatment of swine manure was coupled with anaerobic digestion and microalgal cultivation. A 14-day aerobic treatment reduced the total solid content of swine manure by >15%. Ammonia and carbon dioxide were stripped by the air supplied, and this off-gas was further used to aerate the culture of Chlorella vulgaris. The microalgal growth rates in Bristol medium and the wastewater with the off-gas increased from 0.08 to 0.22 g/L/d and from 0.15 to 0.24 g/L/d, respectively. Meanwhile, the aerobically treated swine manure showed a higher methane yield during anaerobic digestion. The experimental results were used to establish a demonstration unit consisting of a 100 L composter, a 200 L anaerobic digester, a 60 L tubular photobioreactor, and a 300 L micro-open raceway pond.

Spectroscopic analyses of chemical adaptation processes within microalgal biomass in response to changing environments

Energy Technology Data Exchange (ETDEWEB)

Vogt, Frank, E-mail: fvogt@utk.edu; White, Lauren

2015-03-31

Highlights: • Microalgae transform large quantities of inorganics into biomass. • Microalgae interact with their growing environment and adapt their chemical composition. • Sequestration capabilities are dependent on cells’ chemical environments. • We develop a chemometric hard-modeling to describe these chemical adaptation dynamics. • This methodology will enable studies of microalgal compound sequestration. - Abstract: Via photosynthesis, marine phytoplankton transforms large quantities of inorganic compounds into biomass. This has considerable environmental impacts as microalgae contribute for instance to counter-balancing anthropogenic releases of the greenhouse gas CO{sub 2}. On the other hand, high concentrations of nitrogen compounds in an ecosystem can lead to harmful algae blooms. In previous investigations it was found that the chemical composition of microalgal biomass is strongly dependent on the nutrient availability. Therefore, it is expected that algae’s sequestration capabilities and productivity are also determined by the cells’ chemical environments. For investigating this hypothesis, novel analytical methodologies are required which are capable of monitoring live cells exposed to chemically shifting environments followed by chemometric modeling of their chemical adaptation dynamics. FTIR-ATR experiments have been developed for acquiring spectroscopic time series of live Dunaliella parva cultures adapting to different nutrient situations. Comparing experimental data from acclimated cultures to those exposed to a chemically shifted nutrient situation reveals insights in which analyte groups participate in modifications of microalgal biomass and on what time scales. For a chemometric description of these processes, a data model has been deduced which explains the chemical adaptation dynamics explicitly rather than empirically. First results show that this approach is feasible and derives information about the chemical biomass

Spectroscopic analyses of chemical adaptation processes within microalgal biomass in response to changing environments

International Nuclear Information System (INIS)

Vogt, Frank; White, Lauren

2015-01-01

Highlights: • Microalgae transform large quantities of inorganics into biomass. • Microalgae interact with their growing environment and adapt their chemical composition. • Sequestration capabilities are dependent on cells’ chemical environments. • We develop a chemometric hard-modeling to describe these chemical adaptation dynamics. • This methodology will enable studies of microalgal compound sequestration. - Abstract: Via photosynthesis, marine phytoplankton transforms large quantities of inorganic compounds into biomass. This has considerable environmental impacts as microalgae contribute for instance to counter-balancing anthropogenic releases of the greenhouse gas CO 2 . On the other hand, high concentrations of nitrogen compounds in an ecosystem can lead to harmful algae blooms. In previous investigations it was found that the chemical composition of microalgal biomass is strongly dependent on the nutrient availability. Therefore, it is expected that algae’s sequestration capabilities and productivity are also determined by the cells’ chemical environments. For investigating this hypothesis, novel analytical methodologies are required which are capable of monitoring live cells exposed to chemically shifting environments followed by chemometric modeling of their chemical adaptation dynamics. FTIR-ATR experiments have been developed for acquiring spectroscopic time series of live Dunaliella parva cultures adapting to different nutrient situations. Comparing experimental data from acclimated cultures to those exposed to a chemically shifted nutrient situation reveals insights in which analyte groups participate in modifications of microalgal biomass and on what time scales. For a chemometric description of these processes, a data model has been deduced which explains the chemical adaptation dynamics explicitly rather than empirically. First results show that this approach is feasible and derives information about the chemical biomass adaptations

Two-step microalgal biodiesel production using acidic catalyst generated from pyrolysis-derived bio-char

International Nuclear Information System (INIS)

Dong, Tao; Gao, Difeng; Miao, Chao; Yu, Xiaochen; Degan, Charles; Garcia-Pérez, Manuel; Rasco, Barbara; Sablani, Shyam S.; Chen, Shulin

2015-01-01

Highlights: • Highly active catalyst was prepared using bio-char co-produced in Auger pyrolysis. • Catalyst inhibitors in crude oil were effectively removed by a practical refinery process. • Free fatty acids (FFA) content in refined microalgal oil was reduced to less than 0.5%. • A total fatty acid methyl ester (FAME) yield of 99% was obtained via a two-step process. • The inexpensive bio-char catalyst is superior to Amberlyst-15 in pre-esterification. - Abstract: An efficient process for biodiesel production from fast-refined microalgal oil was demonstrated. A low cost catalyst prepared from pyrolysis-derived bio-char, was applied in pre-esterification to reduce free fatty acid (FFA) content. Results showed that the bio-char catalyst was highly active in esterification; however, the performance of the catalyst significantly reduced when crude microalgal oil was used as feedstock. To solve the problem caused by catalyst-fouling, a fast and scalable crude oil refinery procedure was carried out to remove chlorophyll and phospholipids that might degrade the catalyst and the quality of biodiesel. The activity and reusability of bio-char catalyst were remarkably improved in the fast-refined oil. FFA content in the refined microalgal oil was reduced to less than 0.5% after pre-esterification. The bio-char catalyst could be reused for 10 cycles without dramatic loss in activity. The pre-esterification fits the first-order kinetic reaction with activation energy of 42.16 kJ/mol. The activity of bio-char catalyst was superior to commercial Amberlyst-15 under the same reaction condition. A total fatty acid methyl ester (FAME, namely biodiesel) yield of 99% was obtained following the second-step CaO-catalyzed transesterification. The cost-effective bio-char catalyst has great potential for biodiesel production using feedstocks having high FFA content.

Microalgal carbohydrates: an overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels

DEFF Research Database (Denmark)

Markou, Giorgos; Angelidaki, Irini; Georgakakis, Dimitris

2012-01-01

in research is the cultivation of microalgae for lipids production to generate biodiesel. However, there are several other biological or thermochemical conversion technologies, in which microalgal biomass could be used as substrate. However, the high protein content or the low carbohydrate content...... of the majority of the microalgal species might be a constraint for their possible use in these technologies. Moreover, in the majority of biomass conversion technologies, carbohydrates are the main substrate for production of biofuels. Nevertheless, microalgae biomass composition could be manipulated by several......Microalgal biomass seems to be a promising feedstock for biofuel generation. Microalgae have relative high photosynthetic efficiencies, high growth rates, and some species can thrive in brackish water or seawater and wastewater from the food- and agro-industrial sector. Today, the main interest...

Effect of the nutritional status of semi-continuous microalgal cultures on the productivity and biochemical composition of Brachionus plicatilis.

Science.gov (United States)

Ferreira, Martiña; Seixas, Pedro; Coutinho, Paula; Fábregas, Jaime; Otero, Ana

2011-12-01

The rotifer Brachionus plicatilis was cultured using the microalga Isochrysis aff. galbana clone T-ISO as feed. T-ISO was cultured semi-continuously with daily renewal rates of 10%, 20%, 30%, 40%, and 50% of the volume of cultures. The increase of renewal rate led to increasing nutrient and light availability in microalgal cultures, which caused differences in the biochemical composition of microalgal biomass. Growth rate, individual dry weight, organic content, and biomass productivity of rotifer cultures increased in response to higher growth rate in T-ISO cultures. Rotifer growth rate showed a strong negative correlation (R² = 0.90) with the C/N ratio of microalgal biomass. Rotifer dry weight was also affected by nutrient availability of T-ISO cultures, increasing up to 50% from nutrient-limited to nutrient-sufficient conditions. Consequently, biomass productivity of rotifer cultures increased more than twofold with the increase of renewal rate of T-ISO cultures. Rotifer organic content underwent the same trend of total dry weight. Maximum content of polyunsaturated fatty acids was reached in rotifers fed T-ISO from the renewal rate of 40%, with percentages of docosahexaenoic acid (22:6ω-3, DHA) and eicosapentaenoic acid (20:5ω-3, EPA) of 11% and 5% of total fatty acids, respectively. Selecting the most appropriate conditions for microalgal culture can therefore enhance the nutritive quality of microalgal biomass, resulting in a better performance of filter feeders and their nutrient content, and may constitute a useful tool to improve the rearing of fish larvae and other aquaculture organisms that require live feed in some or all the stages of their life cycle.

Advances in photobioreactors for intensive microalgal production: configurations, operating strategies and applications

NARCIS (Netherlands)

Olivieri, G.; Salatino, P.; Marzocchella, A.

2014-01-01

Over the past ten years a great deal of literature has focused on the biotechnological potential of microalgal commercial applications, mainly in the field of biofuel production. However, the biofuel production is not yet competitive, mainly due to the incidence of the photobioreactor technology on

Metabolic engineering of microalgal based biofuel production: prospects and challenges

Directory of Open Access Journals (Sweden)

Chiranjib eBanerjee

2016-03-01

Full Text Available The current scenario in renewable energy is focused on development of alternate and sustainable energy sources, amongst which microalgae stands as one of the promising feedstock for biofuel production. It is well known that microalgae generate much larger amounts of biofuels in a shorter time than other sources based on plant seeds. However, the greatest challenge in a transition to algae-based biofuel production is the various other complications involved in microalgal cultivation, its harvesting, concentration, drying and lipid extraction. Several green microalgae accumulate lipids, especially triacylglycerols (TAGs, which are main precursors in the production of lipid. The various aspects on metabolic pathway analysis of an oleaginous microalgae i.e. Chlamydomonas reinhardtii have elucidated some novel metabolically important genes and this enhances the lipid production in this microalgae. Adding to it, various other aspects in metabolic engineering using OptFlux and effectual bioprocess design also gives an interactive snapshot of enhancing lipid production which ultimately improvises the oil yield. This article reviews the current status of microalgal based technologies for biofuel production, bioreactor process design, flux analysis and it also provides various strategies to increase lipids accumulation via metabolic engineering.

A systems-level approach for investigating organophosphorus pesticide toxicity.

Science.gov (United States)

Zhu, Jingbo; Wang, Jing; Ding, Yan; Liu, Baoyue; Xiao, Wei

2018-03-01

The full understanding of the single and joint toxicity of a variety of organophosphorus (OP) pesticides is still unavailable, because of the extreme complex mechanism of action. This study established a systems-level approach based on systems toxicology to investigate OP pesticide toxicity by incorporating ADME/T properties, protein prediction, and network and pathway analysis. The results showed that most OP pesticides are highly toxic according to the ADME/T parameters, and can interact with significant receptor proteins to cooperatively lead to various diseases by the established OP pesticide -protein and protein-disease networks. Furthermore, the studies that multiple OP pesticides potentially act on the same receptor proteins and/or the functionally diverse proteins explained that multiple OP pesticides could mutually enhance toxicological synergy or additive on a molecular/systematic level. To the end, the integrated pathways revealed the mechanism of toxicity of the interaction of OP pesticides and elucidated the pathogenesis induced by OP pesticides. This study demonstrates a systems-level approach for investigating OP pesticide toxicity that can be further applied to risk assessments of various toxins, which is of significant interest to food security and environmental protection. Copyright © 2017 Elsevier Inc. All rights reserved.

SIMULATION OF MICROALGAL GROWTH IN A CONTINUOUS PHOTOBIOREACTOR WITH SEDIMENTATION AND PARTIAL BIOMASS RECYCLING

Directory of Open Access Journals (Sweden)

C. E. de Farias Silva

Full Text Available Abstract Microalgae are considered as promising feedstocks for the third generation of biofuels. They are autotrophic organisms with high growth rate and can stock an enormous quantity of lipids (about 20 - 40% of their dried cellular weight. This work was aimed at studying the cultivation of Scenedesmus obliquus in a two-stage system composed of a photobioreactor and a settler to concentrate and partially recycle the biomass as a way to enhance the microalgae cellular productivity. It was attempted to specify by simulation and experimental data a relationship between the recycling rate, kinetic parameters of microalgal growth and photobioreactor operating conditions. Scenedesmus obliquus cells were cultivated in a lab-scale flat-plate reactor, homogenized by aeration, and running in continuous flow with a residence time of 1.66 day. Experimental data for the microalgal growth were used in a semi-empirical simulation model. The best results were obtained for Fw=0.2FI, when R = 1 and kd = 0 and 0.05 day-1, with the biomass production in the reactor varying between 8 g L -1 and 14 g L-1, respectively. The mathematical model fitted to the microalgal growth experimental data was appropriate for predicting the efficiency of the reactor in producing Scenedesmus obliquus cells, establishing a relation between cellular productivity and the minimum recycling rate that must be used in the system.

Nile Red Staining for Oil Determination in Microalgal Cells: A New Insight through Statistical Modelling

Directory of Open Access Journals (Sweden)

Ronald Halim

2015-01-01

Full Text Available In the wake of global warming and rapid fossil fuel depletion, microalgae emerge as promising feedstocks for sustainable biofuel production. Nile red staining acts as a rapid diagnostic tool to measure the amount of biodiesel-convertible lipid that the cells accumulate. There is a need for the development of a more uniform staining procedure. In its first phase, this study examined the dependence of microalgal Nile red fluorescence (Tetraselmis suecica in terms of its most pertinent staining variables. A quadratic surface model that successfully described the Nile red fluorescence intensity as a composite function of its variables was generated (r2=0.86. Cell concentration was shown to have a significant effect on the fluorescence intensity. Up to a certain threshold, fluorescence intensity was shown to increase with Nile red dye concentration. In its second phase, the study reviewed findings from previous Nile red studies to elucidate some of the fundamental mechanism underlying the diffusion of Nile red dye molecules into the microalgal cells and their subsequent interaction with intracellular lipids. Through the review process, we were able to develop a simple framework that provided a set of guidelines for the standardization of the Nile red staining procedure across different microalgal species.

Evaluation of levels of select toxic metals in commonly used herbal ...

African Journals Online (AJOL)

Even at low concentrations or levels of exposure, toxic metals have also been reported to pose health risks to man. Aim: To ... Materials/Methods :Herbal medicines (n=8) were purchased from on-the-street vendors and evaluated for levels of five toxic metals (Lead, Nickel, Mercury, Cadmium and Arsenic).Analysis of toxic ...

Tolerance of polar phytoplankton communities to metals

International Nuclear Information System (INIS)

Echeveste, P.; Tovar-Sánchez, A.; Agustí, S.

2014-01-01

Large amounts of pollutants reach polar regions, particularly the Arctic, impacting their communities. In this study we analyzed the toxic levels of Hg, Cd and Pb to natural phytoplankton communities of the Arctic and Southern Oceans, and compared their sensitivities with those observed on phytoplankton natural communities from temperate areas. Mercury was the most toxic metal for both Arctic and Antarctic communities, while both Cd and Pb were toxic only for the Antarctic phytoplankton. Total cell abundance of the populations forming the Arctic community increased under high Cd and Pb concentrations, probably due to a decrease of the grazing pressure or the increase of the most resistant species, although analysis of individual cells indicated that cell death was already induced at the highest levels. These results suggest that phytoplankton may have acquired adapting mechanisms to face high levels of Pb and Cd in the Arctic Ocean. Highlights: • First study analyzing the toxicity of Hg, Cd or Pb to natural polar phytoplankton. • Arctic Ocean communities highly resistant to Cd and Pb, but not to Hg. • Southern Ocean communities sensitive to Cd, Pb and Hg. • Both communities incorporated Pb at a similar level. • Arctic phytoplankton may have acquired adapting mechanisms against Cd and Pb. -- Polar phytoplankton communities are tolerant to Cd and Pb, specially the Arctic ones, suggesting the acquisition of adapting mechanisms to face metals' toxicity

Effects of co-products on the life-cycle impacts of microalgal biodiesel.

Science.gov (United States)

Soratana, Kullapa; Barr, William J; Landis, Amy E

2014-05-01

Microalgal biodiesel production has been investigated for decades, yet it is not commercially available. Part of the problem is that the production process is energy and chemical intensive due, in part, to the high portion of microalgal biomass left as residues. This study investigated cradle-to-gate life-cycle environmental impacts from six different scenarios of microalgal biodiesel and its co-products. Ozone depletion, global warming, photochemical smog formation, acidification and eutrophication potentials were assessed using the Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI). Monte Carlo Analysis was conducted to investigate the processes with major contribution in each impact category. The market opportunity for each co-product was examined based on supply, demand and prices of the products that could potentially be substituted by the co-products. The results indicated that the scenario with the least life-cycle environmental impacts in all the five impact categories with the highest net energy ratio was the scenario utilizing a multitude of co-products including bioethanol from lipid-extracted microalgae (LEA), biomethane (to produce electricity and heat) from simultaneous saccharification-fermentation (SSF) residues, land-applied material from SSF residue anaerobic digestion (AD) solid digestate, recycling nutrients from SSF residue AD liquid digestate and CO2 recovered from SSF process contributed. Decreasing the energy consumption of the centrifuge in the land-applied material production process and increasing the lipid content of microalgae can reduce environmental footprints of the co-products. The same scenario also had the highest total income indicating their potential as co-products in the market. Copyright © 2014 Elsevier Ltd. All rights reserved.

Resource Assessment for Microalgal/Emergent Aquatic Biomass Systems in the Arid Southwest: Final Report

Energy Technology Data Exchange (ETDEWEB)

Vigon, B. W.; Arthur, M. F.; Taft, L. G.; Wagner, C. K.; Lipinsky, E. S.; Litchfield, J. H.; McCandlish, C. D.; Clark, R.

1982-12-23

This research project has been designed to facilitate the eventual selection of biomass production systems using aquatic species (microalgal and emergent aquatic plant species (MEAP) which effectively exploit the potentially available resources of the Southwest.

Runaway chemical reaction exposes community to highly toxic chemicals

International Nuclear Information System (INIS)

Kaszniak, Mark; Vorderbrueggen, John

2008-01-01

The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted a comprehensive investigation of a runaway chemical reaction at MFG Chemical (MFG) in Dalton, Georgia on April 12, 2004 that resulted in the uncontrolled release of a large quantity of highly toxic and flammable allyl alcohol and allyl chloride into the community. Five people were hospitalized and 154 people required decontamination and treatment for exposure to the chemicals. This included police officers attempting to evacuate the community and ambulance personnel who responded to 911 calls from residents exposed to the chemicals. This paper presents the findings of the CSB report (U.S. Chemical Safety and Hazard Investigation Board (CSB), Investigation Report: Toxic Chemical Vapor Cloud Release, Report No. 2004-09-I-GA, Washington DC, April 2006) including a discussion on tolling practices; scale-up of batch reaction processes; Process Safety Management (PSM) and Risk Management Plan (RMP) implementation; emergency planning by the company, county and the city; and emergency response and mitigation actions taken during the incident. The reactive chemical testing and atmospheric dispersion modeling conducted by CSB after the incident and recommendations adopted by the Board are also discussed

Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

International Nuclear Information System (INIS)

Gerhardt, A.; Janssens de Bisthoven, L.; Soares, A.M.V.M.

2004-01-01

The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor[reg], based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC 50 -48 h: pH-AMD=5.8) and a pH- dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC 50 -48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed. - Toxicity of acid mine drainage was evaluated by macroinvertebrate bioassessment and a new on-line rapid behavioural toxicity test with Atyaephyra desmaresti (Crustacea)

Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

Energy Technology Data Exchange (ETDEWEB)

Gerhardt, A.; Janssens de Bisthoven, L.; Soares, A.M.V.M

2004-07-01

The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor[reg], based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC{sub 50}-48 h: pH-AMD=5.8) and a pH- dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC{sub 50}-48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed. - Toxicity of acid mine drainage was evaluated by macroinvertebrate bioassessment and a new on-line rapid behavioural toxicity test with Atyaephyra desmaresti (Crustacea)

Toxicity assessment of pesticide triclosan by aquatic organisms and degradation studies.

Science.gov (United States)

Taştan, Burcu Ertit; Tekinay, Turgay; Çelik, Hatice Sena; Özdemir, Caner; Cakir, Dilara Nur

2017-12-01

Triclosan is considered as an important contaminant and is widely used in personal care products as an antimicrobial agent. This study demonstrates the biodegradation of triclosan by two freshwater microalgae and the acute toxicity of triclosan and 2,4-dichlorophenol. The effects of culture media and light on biodegradation of triclosan and the changing morphology of microalgae were systematically studied. Geitlerinema sp. and Chlorella sp. degraded 82.10% and 92.83% of 3.99 mg/L of triclosan at 10 days, respectively. The microalgal growth inhibition assay confirmed absence of toxic effects of triclosan on Chlorella sp., even at higher concentration (50 mg/L) after 72 h exposure. HPLC analysis showed that 2,4-dichlorophenol was produced as degradation product of triclosan by Geitlerinema sp. and Chlorella sp. This study proved to be beneficial to understand biodegradation and acute toxicity of triclosan by microalgae in order to provide aquatic environmental protection. Copyright © 2017 Elsevier Inc. All rights reserved.

Macroinvertebrate response to acid mine drainage: community metrics and on-line behavioural toxicity bioassay

Energy Technology Data Exchange (ETDEWEB)

A. Gerhardt; L. Janssens de Bisthoven; A.M.V.M. Soares [University of Aveiro, Aveiro (Portugal). Department of Biology

2004-07-01

The hypothesis is tested that toxicity of acid mine drainage can be detected by a selection of existing macroinvertebrate community and bioindicator metrices supplemented by toxicity tests with the local mosquitofish Gambusia holbrooki Girard and the shrimp Atyaephyra desmaresti Millet. The behavioural responses of A. desmaresti to acid mine drainage were recorded in the Multispecies Freshwater Biomonitor{reg_sign}, based on behaviour and survival as parameters. Bioassessment methods were based on community diversity, structure, function, and bioindicators and supplemented by chemical analysis (temperature, pH, metals). The Biological Monitoring Working Party adapted for the Iberian Peninsula, the number of predators (Coleoptera, Hemiptera) and the number of Ephemeroptera and Trichoptera taxa differentiated the sites well. The on-line toxicity test revealed pH-dependent acute toxicity of the acid mine drainage for the shrimp (LC{sub 50}-48 h: pH-AMD=5.8) and a pH-dependent decrease in locomotory activity with the lowest-observed-response-times (LORTs) within 5 h of exposure. Shrimp were more sensitive to acid mine drainage than fish (LC{sub 50}-48 h: pH-AMD=4.9). A new multimetric index combining toxicity testing and bioassessment methods is proposed.

Consolidated bioprocessing of microalgal biomass to carboxylates by a mixed culture of cow rumen bacteria using anaerobic sequencing batch reactor (ASBR).

Science.gov (United States)

Zhao, Baisuo; Liu, Jie; Frear, Craig; Holtzapple, Mark; Chen, Shulin

2016-12-01

This study employed mixed-culture consolidated bioprocessing (CBP) to digest microalgal biomass in an anaerobic sequencing batch reactor (ASBR). The primary objectives are to evaluate the impact of hydraulic residence time (HRT) on the productivity of carboxylic acids and to characterize the bacterial community. HRT affects the production rate and patterns of carboxylic acids. For the 5-L laboratory-scale fermentation, a 12-day HRT was selected because it offered the highest productivity of carboxylic acids and it synthesized longer chains. The variability of the bacterial community increased with longer HRT (R 2 =0.85). In the 5-L laboratory-scale fermentor, the most common phyla were Firmicutes (58.3%), Bacteroidetes (27.4%), and Proteobacteria (11.9%). The dominant bacterial classes were Clostridia (29.8%), Bacteroidia (27.4%), Tissierella (26.2%), and Betaproteobacteria (8.9%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Encapsulation of Multiple Microalgal Cells via a Combination of Biomimetic Mineralization and LbL Coating.

Science.gov (United States)

Kim, Minjeong; Choi, Myoung Gil; Ra, Ho Won; Park, Seung Bin; Kim, Yong-Joo; Lee, Kyubock

2018-02-13

The encapsulation of living cells is appealing for its various applications to cell-based sensors, bioreactors, biocatalysts, and bioenergy. In this work, we introduce the encapsulation of multiple microalgal cells in hollow polymer shells of rhombohedral shape by the following sequential processes: embedding of microalgae in CaCO₃ crystals; layer-by-layer (LbL) coating of polyelectrolytes; and removal of sacrificial crystals. The microcapsule size was controlled by the alteration of CaCO₃ crystal size, which is dependent on CaCl₂/Na₂CO₃ concentration. The microalgal cells could be embedded in CaCO₃ crystals by a two-step process: heterogeneous nucleation of crystal on the cell surface followed by cell embedment by the subsequent growth of crystal. The surfaces of the microalgal cells were highly favorable for the crystal growth of calcite; thus, micrometer-sized microalgae could be perfectly occluded in the calcite crystal without changing its rhombohedral shape. The surfaces of the microcapsules, moreover, could be decorated with gold nanoparticles, Fe₃O₄ magnetic nanoparticles, and carbon nanotubes (CNTs), by which we would expect the functionalities of a light-triggered release, magnetic separation, and enhanced mechanical and electrical strength, respectively. This approach, entailing the encapsulation of microalgae in semi-permeable and hollow polymer microcapsules, has the potential for application to microbial-cell immobilization for high-biomass-concentration cultivation as well as various other bioapplications.

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

Utilization of Microalgal Biofractions for Bioethanol, Higher Alcohols, and Biodiesel Production: A Review

Directory of Open Access Journals (Sweden)

Marwa M. El-Dalatony

2017-12-01

Full Text Available Biomass is a crucial energy resource used for the generation of electricity and transportation fuels. Microalgae exhibit a high content of biocomponents which makes them a potential feedstock for the generation of ecofriendly biofuels. Biofuels derived from microalgae are suitable carbon-neutral replacements for petroleum. Fermentation is the major process for metabolic conversion of microalgal biocompounds into biofuels such as bioethanol and higher alcohols. In this review, we explored the use of all three major biocomponents of microalgal biomass including carbohydrates, proteins, and lipids for maximum biofuel generation. Application of several pretreatment methods for enhancement the bioavailability of substrates (simple sugar, amino acid, and fatty acid was discussed. This review goes one step further to discuss how to direct these biocomponents for the generation of various biofuels (bioethanol, higher alcohol, and biodiesel through fermentation and transesterification processes. Such an approach would result in the maximum utilization of biomasses for economically feasible biofuel production.

Towards microalgal triglycerides in the commodity markets.

Science.gov (United States)

Benvenuti, Giulia; Ruiz, Jesús; Lamers, Packo P; Bosma, Rouke; Wijffels, René H; Barbosa, Maria J

2017-01-01

Microalgal triglycerides (TAGs) hold great promise as sustainable feedstock for commodity industries. However, to determine research priorities and support business decisions, solid techno-economic studies are essential. Here, we present a techno-economic analysis of two-step TAG production (growth reactors are operated in continuous mode such that multiple batch-operated stress reactors are inoculated and harvested sequentially) for a 100-ha plant in southern Spain using vertically stacked tubular photobioreactors. The base case is established with outdoor pilot-scale data and based on current process technology. For the base case, production costs of 6.7 € per kg of biomass containing 24% TAG (w/w) were found. Several scenarios with reduced production costs were then presented based on the latest biological and technological advances. For instance, much effort should focus on increasing the photosynthetic efficiency during the stress and growth phases, as this is the most influential parameter on production costs (30 and 14% cost reduction from base case). Next, biological and technological solutions should be implemented for a reduction in cooling requirements (10 and 4.5% cost reduction from base case when active cooling is avoided and cooling setpoint is increased, respectively). When implementing all the suggested improvements, production costs can be decreased to 3.3 € per kg of biomass containing 60% TAG (w/w) within the next 8 years. With our techno-economic analysis, we indicated a roadmap for a substantial cost reduction. However, microalgal TAGs are not yet cost efficient when compared to their present market value. Cost-competiveness strictly relies on the valorization of the whole biomass components and on cheaper PBR designs (e.g. plastic film flat panels). In particular, further research should focus on the development and commercialization of PBRs where active cooling is avoided and stable operating temperatures are maintained by the water

Energy aspects of microalgal biodiesel production

Directory of Open Access Journals (Sweden)

Edith Martinez-Guerra

2016-03-01

Full Text Available Algal biodiesel production will play a significant role in sustaining future transportation fuel supplies. A large number of researchers around the world are investigating into making this process sustainable by increasing the energy gains and by optimizing resource-utilization efficiencies. Although, research is being pursued aggressively in all aspects of algal biodiesel production from microalgal cell cultivation, cell harvesting, and extraction and transesterification steps to the final product separation and purification, there is a large disparity in the data presented in recent reports making it difficult to assess the real potential of microalgae as a future energy source. This article discusses some of the key issues in energy consumption in the process of algal biodiesel production and identifies the areas for improvement to make this process energy-positive and sustainable.

Microalgal cultivation for value-added products: a critical enviro-economical assessment.

Science.gov (United States)

Kothari, Richa; Pandey, Arya; Ahmad, Shamshad; Kumar, Ashwani; Pathak, Vinayak V; Tyagi, V V

2017-08-01

The present review focuses on the cultivation of algal biomass for generating value-added products (VAP) and to assess their economic benefits and harmful environmental impact. Additionally, the impact of bioreactor designs on the yield of microalgal biomass for VAP is also considered. All these factors are discussed in relation to the impact of microalgae production on the bio-economy sector of commercial biotechnology.

Large-scale biodiesel production using flue gas from coal-fired power plants with Nannochloropsis microalgal biomass in open raceway ponds.

Science.gov (United States)

Zhu, Baohua; Sun, Faqiang; Yang, Miao; Lu, Lin; Yang, Guanpin; Pan, Kehou

2014-12-01

The potential use of microalgal biomass as a biofuel source has raised broad interest. Highly effective and economically feasible biomass generating techniques are essential to realize such potential. Flue gas from coal-fired power plants may serve as an inexpensive carbon source for microalgal culture, and it may also facilitate improvement of the environment once the gas is fixed in biomass. In this study, three strains of the genus Nannochloropsis (4-38, KA2 and 75B1) survived this type of culture and bloomed using flue gas from coal-fired power plants in 8000-L open raceway ponds. Lower temperatures and solar irradiation reduced the biomass yield and lipid productivities of these strains. Strain 4-38 performed better than the other two as it contained higher amounts of triacylglycerols and fatty acids, which are used for biodiesel production. Further optimization of the application of flue gas to microalgal culture should be undertaken. Copyright © 2014 Elsevier Ltd. All rights reserved.

Benthic microalgal production in the Arctic: Applied methods and status of the current database

DEFF Research Database (Denmark)

Glud, Ronnie Nøhr; Woelfel, Jana; Karsten, Ulf

2009-01-01

The current database on benthic microalgal production in Arctic waters comprises 10 peer-reviewed and three unpublished studies. Here, we compile and discuss these datasets, along with the applied measurement approaches used. The latter is essential for robust comparative analysis and to clarify ...

A novel microalgal system for energy production with nitrogen cycling

Energy Technology Data Exchange (ETDEWEB)

Minowa, T.; Sawayama, S. [National Institute for Resources and Environment, Tsukuba (Japan)

1999-08-01

A microalga, Chlorella vulgaris, could grow in the recovered solution from the low temperature catalytic gasification of itself, by which methane rich fuel gas was obtained. All nitrogen in the microalga was converted to ammonia during the gasification, and the recovered solution, in which ammonia was dissolved, could be used as nitrogen nutrient. The result of the energy evaluation indicated that the novel microalgal system for energy production with nitrogen cycling could be created. 9 refs., 3 tabs.

Biodiesel production from microalgal isolates of southern Pakistan and quantification of FAMEs by GC-MS/MS analysis

Directory of Open Access Journals (Sweden)

Musharraf Syed

2012-12-01

Full Text Available Abstract Background Microalgae have attracted major interest as a sustainable source for biodiesel production on commercial scale. This paper describes the screening of six microalgal species, Scenedesmus quadricauda, Scenedesmus acuminatus, Nannochloropsis sp., Anabaena sp., Chlorella sp. and Oscillatoria sp., isolated from fresh and marine water resources of southern Pakistan for biodiesel production and the GC-MS/MS analysis of their fatty acid methyl esters (FAMEs. Results Growth rate, biomass productivity and oil content of each algal species have been investigated under autotrophic condition. Biodiesel was produced from algal oil by acid catalyzed transesterification reaction and resulting fatty acid methyl esters (FAMEs content was analyzed by GC/MS. Fatty acid profiling of the biodiesel, obtained from various microalgal oils showed high content of C-16:0, C-18:0, cis-Δ9C-18:1, cis-Δ11C-18:1 (except Scenedesmus quadricauda and 10-hydroxyoctadecanoic (except Scenedesmus acuminatus. Absolute amount of C-14:0, C-16:0 and C-18:0 by a validated GC-MS/MS method were found to be 1.5-1.7, 15.0-42.5 and 4.2-18.4 mg/g, respectively, in biodiesel obtained from various microalgal oils. Biodiesel was also characterized in terms of cetane number, kinematic viscosity, density and higher heating value and compared with the standard values. Conclusion Six microalgae of local origin were screened for biodiesel production. A method for absolute quantification of three important saturated fatty acid methyl esters (C-14, C-16 and C-18 by gas chromatography-tandem mass spectrometry (GC-MS/MS, using multiple reactions monitoring (MRM mode, was employed for the identification and quantification of biodiesels obtained from various microalgal oils. The results suggested that locally found microalgae can be sustainably harvested for the production of biodiesel. This offers the tremendous economic opportunity for an energy-deficient nation.

Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands.

Directory of Open Access Journals (Sweden)

Carmen Rojo

Full Text Available The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abundance and composition of planktonic and benthic microalgae was determined. Variation partitioning analysis (as explained by spatial distance or environmental factors was applied to each seasonal dataset by means of partial redundancy analysis. Our results show that microalgal assemblages were structured by spatial and environmental factors depending on the hydrological period of the year. At the onset of hydroperiod and during flooding, neutral effects dominated community dynamics, but niche-based local effects resulted in more structured algal communities at the final periods of desiccating water bodies. Results suggest that climate-mediated effects on hydrology can influence the relative role of spatial and environmental factors on metacommunities of microalgae. Such variability needs to be accounted in order to describe accurately community dynamics in tropical coastal wetlands.

Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands.

Science.gov (United States)

Rojo, Carmen; Mesquita-Joanes, Francesc; Monrós, Juan S; Armengol, Javier; Sasa, Mahmood; Bonilla, Fabián; Rueda, Ricardo; Benavent-Corai, José; Piculo, Rubén; Segura, M Matilde

2016-01-01

The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abundance and composition of planktonic and benthic microalgae was determined. Variation partitioning analysis (as explained by spatial distance or environmental factors) was applied to each seasonal dataset by means of partial redundancy analysis. Our results show that microalgal assemblages were structured by spatial and environmental factors depending on the hydrological period of the year. At the onset of hydroperiod and during flooding, neutral effects dominated community dynamics, but niche-based local effects resulted in more structured algal communities at the final periods of desiccating water bodies. Results suggest that climate-mediated effects on hydrology can influence the relative role of spatial and environmental factors on metacommunities of microalgae. Such variability needs to be accounted in order to describe accurately community dynamics in tropical coastal wetlands.

Encapsulation of Multiple Microalgal Cells via a Combination of Biomimetic Mineralization and LbL Coating

Directory of Open Access Journals (Sweden)

Minjeong Kim

2018-02-01

Full Text Available The encapsulation of living cells is appealing for its various applications to cell-based sensors, bioreactors, biocatalysts, and bioenergy. In this work, we introduce the encapsulation of multiple microalgal cells in hollow polymer shells of rhombohedral shape by the following sequential processes: embedding of microalgae in CaCO3 crystals; layer-by-layer (LbL coating of polyelectrolytes; and removal of sacrificial crystals. The microcapsule size was controlled by the alteration of CaCO3 crystal size, which is dependent on CaCl2/Na2CO3 concentration. The microalgal cells could be embedded in CaCO3 crystals by a two-step process: heterogeneous nucleation of crystal on the cell surface followed by cell embedment by the subsequent growth of crystal. The surfaces of the microalgal cells were highly favorable for the crystal growth of calcite; thus, micrometer-sized microalgae could be perfectly occluded in the calcite crystal without changing its rhombohedral shape. The surfaces of the microcapsules, moreover, could be decorated with gold nanoparticles, Fe3O4 magnetic nanoparticles, and carbon nanotubes (CNTs, by which we would expect the functionalities of a light-triggered release, magnetic separation, and enhanced mechanical and electrical strength, respectively. This approach, entailing the encapsulation of microalgae in semi-permeable and hollow polymer microcapsules, has the potential for application to microbial-cell immobilization for high-biomass-concentration cultivation as well as various other bioapplications.

Adsorptive removal of cesium using bio fuel extraction microalgal waste

Energy Technology Data Exchange (ETDEWEB)

Inoue, Katsutoshi, E-mail: inoue@elechem.chem.saga-u.ac.jp [Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502 (Japan); Gurung, Manju [Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502 (Japan); Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John' s, NL, Canada A1B 3X5 (Canada); Adhikari, Birendra Babu; Alam, Shafiq [Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John' s, NL, Canada A1B 3X5 (Canada); Kawakita, Hidetaka; Ohto, Keisuke [Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502 (Japan); Kurata, Minoru [Research Laboratories, DENSO CORPORATION, Minamiyama 500-1, Komenoki, Nisshin, Aichi 470-0111 (Japan); Atsumi, Kinya [New Business Promotion Dept., DENSO CORPORATION, Showa-cho 1-1, Kariya, Aichi 448-8661 (Japan)

2014-04-01

Highlights: • A novel biosorbent was prepared from the microalgal waste after biofuel extraction. • Higher selectivity and adsorption efficiency of the adsorbent for Cs{sup +} over Na{sup +} ions from aqueous solutions. • Potential candidate and eco-friendly alternative to the commercial resins such as zeolite. - Abstract: An adsorption gel was prepared from microalgal waste after extracting biodiesel oil by a simple chemical treatment of crosslinking using concentrated sulfuric acid. The adsorbent exhibited notably high selectivity and adsorption capacity towards Cs{sup +} over Na{sup +} from aqueous solutions, within the pH range of slightly acidic to neutral. The adsorption followed Langmuir isotherm and the maximum adsorption capacity of the gel for Cs{sup +} calculated from Langmuir model was found to be 1.36 mol kg{sup −1}. Trace concentration of Cs{sup +} ions present in aqueous streams was successfully separated from Na{sup +} ions using a column packed with the adsorbent at pH 6.5. The adsorption capacity of the gel towards Cs{sup +} in column operation was 0.13 mol kg{sup −1}. Although the adsorbed Cs{sup +} ions were easily eluted using 1 M hydrochloric acid solution, simple incineration is proposed as an alternative for the treatment of adsorbent loaded with radioactive Cs{sup +} ions due to the combustible characteristics of this adsorbent.

[Trends of microalgal biotechnology: a view from bibliometrics].

Science.gov (United States)

Yang, Xiaoqiu; Wu, Yinsong; Yan, Jinding; Song, Haigang; Fan, Jianhua; Li, Yuanguang

2015-10-01

Microalgae is a single-cell organism with the characteristics of high light energy utilization rate, fast growth rate, high-value bioactive components and high energy material content. Therefore, microalgae has broad application prospects in food, feed, bioenergy, carbon sequestration, wastewater treatment and other fields. In this article, the microalgae biotechnology development in recent years were fully consulted, through analysis from the literature and patent. The progress of microalgal biotechnology at home and abroad is compared and discussed. Furthermore, the project layout, important achievements and development bottlenecks of microalgae biotechnology in our country were also summarized. At last, future development directions of microalgae biotechnology were discussed.

Mechanisms and manifestations of toxic actions at the bone tissue level

International Nuclear Information System (INIS)

1998-01-01

The principal abnormalities determined by toxic at the bone level are: osteoporosis, osteomalacia, osteosclerosis or osteopetrosis. The principal toxics having a noxiousness at the bone level are: the fluorine, the phosphorus, the lead, the bismuth, the cadmium and the strontium. The strontium 90 has an important radioactivity that gives at the bone level osteosarcomas or at low doses, leukemoid reactions and marrow angiosarcoma. (N.C.)

Microalgal-biochar immobilized complex: A novel efficient biosorbent for cadmium removal from aqueous solution.

Science.gov (United States)

Shen, Ying; Li, Huan; Zhu, Wenzhe; Ho, Shih-Hsin; Yuan, Wenqiao; Chen, Jianfeng; Xie, Youping

2017-11-01

The feasibility of the bioremediation of cadmium (Cd) using microalgal-biochar immobilized complex (MBIC) was investigated. Major operating parameters (e.g., pH, biosorbent dosage, initial Cd(II) concentration and microalgal-biochar ratio) were varied to compare the treatability of viable algae (Chlorella sp.), biochar and MBIC. The biosorption isotherms obtained by using algae or biochar were found to have satisfactory Langmuir predictions, while the best fitting adsorption isotherm model for MBIC was the Sips model. The maximum Cd(II) adsorption capacity of MBIC with a Chlorella sp.: biochar ratio of 2:3 (217.41mgg -1 ) was higher than that of Chlorella sp. (169.92mgg -1 ) or biochar (95.82mgg -1 ) alone. The pseudo-second-order model fitted the biosorption process of MBIC well (R 2 >0.999). Moreover, zeta potential, SEM and FTIR studies revealed that electrostatic attraction, ion exchange and surface complexation were the main mechanisms responsible for Cd removal when using MBIC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined effects of gamma irradiation and cadmium on cellular and population-level endpoints of the micro-alga Pseudokirchneriella subcapitata

Energy Technology Data Exchange (ETDEWEB)

Bradshaw, C. [Stockholm University (Sweden); Abdul Meseh, D.; Alasawi, H.; Qiang, M.; Nascimento, F. [Dept of Ecology, Environment and Plant Sciences (Sweden)

2014-07-01

A major challenge in evaluating the risks of radiation to organisms is that radioactive substances often co-occur with other contaminants in the environment. The combined effects of multiple contaminants is poorly understood, particularly where radiation is involved, but mixture toxicity can give rise to synergistic, antagonistic or additive effects. The challenge of understanding mixture toxicity in a radiation context is the focus of one of the work packages of the STAR EU Network of Excellence in Radioecology, of which this study is a part. This paper presents results from an experiment where the green micro-alga Pseudokirchneriella subcapitata was exposed to both acute external gamma irradiation and the toxic metal cadmium (Cd) (over 72 hours); the experiment had a fully factorial design with 4 gamma doses and 4 Cd concentrations. The endpoints measured were chosen to reflect subcellular, cellular and population-level effects: antioxidant enzyme expression; membrane damage; protein, vitamin and pigment content of the cells; individual cell biomass and growth; population growth (biomass per ml and cells per ml). Preliminary results suggest effects of both Cd and gamma on some of the cellular and subcellular endpoints such as thiamine (vitamin B1) and chlorophyll concentrations in the cells, and individual cell biomass. In some cases interactive effects of the combined Cd and gamma treatments were seen, and these appeared to be dose level dependent. This lack of a consistent pattern of interactive mixture toxicity effects across the endpoints measured means that such effects would be very hard to predict in a risk assessment context. The lack of measurable effects at the population level was probably due to the short experimental duration (72 hours). Other experiments in our research group on the same micro-alga species that have looked at longer term effects (weeks) have shown that effects may not manifest themselves until at least a week after an acute gamma

High-throughput, label-free, single-cell, microalgal lipid screening by machine-learning-equipped optofluidic time-stretch quantitative phase microscopy.

Science.gov (United States)

Guo, Baoshan; Lei, Cheng; Kobayashi, Hirofumi; Ito, Takuro; Yalikun, Yaxiaer; Jiang, Yiyue; Tanaka, Yo; Ozeki, Yasuyuki; Goda, Keisuke

2017-05-01

The development of reliable, sustainable, and economical sources of alternative fuels to petroleum is required to tackle the global energy crisis. One such alternative is microalgal biofuel, which is expected to play a key role in reducing the detrimental effects of global warming as microalgae absorb atmospheric CO 2 via photosynthesis. Unfortunately, conventional analytical methods only provide population-averaged lipid amounts and fail to characterize a diverse population of microalgal cells with single-cell resolution in a non-invasive and interference-free manner. Here high-throughput label-free single-cell screening of lipid-producing microalgal cells with optofluidic time-stretch quantitative phase microscopy was demonstrated. In particular, Euglena gracilis, an attractive microalgal species that produces wax esters (suitable for biodiesel and aviation fuel after refinement), within lipid droplets was investigated. The optofluidic time-stretch quantitative phase microscope is based on an integration of a hydrodynamic-focusing microfluidic chip, an optical time-stretch quantitative phase microscope, and a digital image processor equipped with machine learning. As a result, it provides both the opacity and phase maps of every single cell at a high throughput of 10,000 cells/s, enabling accurate cell classification without the need for fluorescent staining. Specifically, the dataset was used to characterize heterogeneous populations of E. gracilis cells under two different culture conditions (nitrogen-sufficient and nitrogen-deficient) and achieve the cell classification with an error rate of only 2.15%. The method holds promise as an effective analytical tool for microalgae-based biofuel production. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

Assessing the Effect of Pretreatments on the Structure and Functionality of Microbial Communities for the Bioconversion of Microalgae to Biogas

Directory of Open Access Journals (Sweden)

Olivia Córdova

2018-06-01

Full Text Available Microalgae biomethanization is driven by anaerobic sludge associated microorganisms and is generally limited by the incomplete hydrolysis of the microalgae cell wall, which results in a low availability of microalgal biomass for the methanogenic community. The application of enzymatic pretreatments, e.g., with hydrolytic enzymes, is among the strategies used to work around the incomplete hydrolysis of the microalgae cell wall. Despite the proven efficacy of these pretreatments in increasing biomethanization, the changes that a given pretreatment may cause to the anaerobic sludge associated microorganisms during biomethanization are still unknown. This study evaluated the changes in the expression of the metatranscriptome of anaerobic sludge associated microorganisms during Chlorella sorokiniana biomethanization without pretreatment (WP (control and pretreated with commercial cellulase in order to increase the solubilization of the microalgal organic matter. Pretreated microalgal biomass experienced significant increases in biogas the production. The metatranscriptomic analysis of control samples showed functionally active microalgae cells, a bacterial community dominated by γ- and δ-proteobacteria, and a methanogenic community dominated by Methanospirillum hungatei. In contrast, pretreated samples were characterized by the absence of active microalgae cells and a bacteria population dominated by species of the Clostridia class. These differences are also related to the differential activation of metabolic pathways e.g., those associated with the degradation of organic matter during its biomethanization.

Re-envisioning the renewable fuel standard to minimize unintended consequences: A comparison of microalgal diesel with other biodiesels

International Nuclear Information System (INIS)

Soratana, Kullapa; Khanna, Vikas; Landis, Amy E.

2013-01-01

Highlights: • Conducted a life cycle assessment (LCA) of microalgal diesel from PBR to combustion. • Compared the results with other existing LCA results of petroleum and other biodiesels. • Assessed the current Renewable Fuel Standard (RFS2). • Proposed an approach to set emission thresholds for eutrophication (EP) and smog formation potentials (PSP). • Future RFS should include a life-cycle emissions threshold for EP and PSP. - Abstract: The Renewable Fuel Standard 2 (RFS2) program under the Energy Independence and Security Act of 2007 set a life-cycle emission reduction threshold to only greenhouse gas (GHG) emissions; this type of single-dimensional threshold could lead to the unintended trading of one environmental problem for another. Many of the environmental impacts resulting over the life cycle of oil-crop biodiesel fuels manifest in the agricultural phase of production in the form of water quality degradation. This study investigated the extent to which different biofuels meet the RFS GHG requirement, and presents alternative strategies for minimizing unintended consequences. In addition to life-cycle global warming potential (GWP), the eutrophication potential (EP) and photochemical smog formation potential (PSP) from microalgal diesel were compared to the impacts resulting from petroleum-based diesel, soybean diesel and canola diesel. The results showed tradeoffs between GWP and eutrophication potential when microalgal diesel was compared to soybean diesel. Future RFS criteria should include EP and PSP metrics, however establishing thresholds like the GHG management approach may not be appropriate for these other impacts. Two possible strategies to setting life-cycle eutrophication standards are to establish a threshold based on first generation biofuels, as opposed to petro-fuels or to set maximum levels of EP loads for major watersheds or coastal areas. To decrease PSP, together with existing standards for tailpipe emissions, future RFSs

Energy analysis and environmental impacts of microalgal biodiesel in China

International Nuclear Information System (INIS)

Liao Yanfen; Huang Zehao; Ma Xiaoqian

2012-01-01

The entire life cycle of biodiesel produced by microalgal biomasses was evaluated using the method of life cycle assessment (LCA) to identify and quantify the fossil energy requirements and environmental impact loading of the system. The life cycle considers microalgae cultivation, harvesting, drying, oil extraction, anaerobic digestion, oil transportation, esterification, biodiesel transportation and biodiesel combustion. The investigation results show that the fossil energy requirement for the biodiesel production is 0.74 MJ/MJ biodiesel, indicating that 1 MJ of biodiesel requires an input of 0.74 MJ of fossil energy. Accordingly, biodiesel production is feasible as an energy producing process. The environmental impact loading of microalgal biodiesel is 3.69 PET 2010 (Person Equivalents, Targeted, in 2010) and the GWP is 0.16 kg CO 2-eq /MJ biodiesel. The effects of photochemical ozone formation were greatest among all calculated categorization impacts. The fossil energy requirement and GWP in this operation were found to be particularly sensitive to oil content, drying rate and esterification rate. Overall, the results presented herein indicate that the cultivation of microalgae has the potential to produce an environmentally sustainable feedstock for the production of biodiesel. - Highlights: ► Do energy analysis and environmental impacts of algal biodiesel in China. ► GWP and energy consumption are sensitive to lipid content and drying rate. ► Fossil energy consumption for algal biodiesel is 0.74 MJ/MJ. ► Microalgae are an environmentally sustainable feedstock for biodiesel production.

Contribution of transformation products towards the total herbicide toxicity to tropical marine organisms.

Science.gov (United States)

Mercurio, Philip; Eaglesham, Geoff; Parks, Stephen; Kenway, Matt; Beltran, Victor; Flores, Florita; Mueller, Jochen F; Negri, Andrew P

2018-03-19

The toxicity of herbicide degradation (transformation) products is rarely taken into account, even though these are commonly detected in the marine environment, sometimes at concentrations higher than the parent compounds. Here we assessed the potential contribution of toxicity by transformation products of five photosystem II herbicides to coral symbionts (Symbiodinium sp.), the green algae Dunaliella sp., and prawn (Penaeus monodon) larvae. Concentration-dependent inhibition of photosynthetic efficiency (∆F/F m ') was observed for all herbicides in both microalgal species. The toxicity of solutions of aged diuron solutions containing transformation products to Symbiodinium sp. and Dunaliella sp. was greater than could be explained by the concentrations of diuron measured, indicating transformation products contributed to the inhibition of ∆F/F m '. However, the toxicity of aged atrazine, simazine, hexazinone, and ametryn solutions could be explained by the concentration of parent herbicide, indicating no contribution by transformation products. Prawn larval metamorphosis was not sensitive to the herbicides, but preliminary results indicated some toxicity of the transformation products of atrazine and diuron. Risk assessments should take into account the contribution of herbicide transformation products; however, further studies are clearly needed to test the toxicity of a far wider range of transformation products to a representative diversity of relevant taxa.

Phosphorus removal using a microalgal biofilm in a new biofilm photobioreactor for tertiary wastewater treatment

Czech Academy of Sciences Publication Activity Database

Sukačová, Kateřina; Trtílek, M.; Rataj, Tomáš

2015-01-01

Roč. 75, mar (2015), s. 55-63 ISSN 0043-1354 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : microalgal biofilm * phosphorus removal * wastewater treatment Subject RIV: EH - Ecology, Behaviour Impact factor: 5.991, year: 2015

Microalgal composition and primary production in Arctic sea ice: a seasonal study from Kobbeijord (Kangerluarsunnguaq), West Greenland

DEFF Research Database (Denmark)

Mikkelsen, Ditte Marie; Rysgaard, Søren; Glud, Ronnie N.

2008-01-01

We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration......) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom...... (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority...

Microalgal composition and primary production in Arctic sea ice: a seasonal study from Kobbeijord (Kangerluarsunnguaq), West Greenland

DEFF Research Database (Denmark)

Mikkelsen, Ditte Marie; Rysgaard, Søren; Glud, Ronnie N.

2008-01-01

We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration...... (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority......) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom...

Enhanced the energy outcomes from microalgal biomass by the novel biopretreatment

International Nuclear Information System (INIS)

He, Shuai; Fan, Xiaolei; Luo, Shengjun; Katukuri, Naveen Reddy; Guo, Rongbo

2017-01-01

Highlights: • The micro-aerobic pretreatment was used to improve energy yield of Chlorella sp. • The Bacillus licheniformis was confirmed to damage the cell wall of microalgae. • Obtained energy from Chlorella sp. was improved by 12.3%. • Pretreatment time was decreased from 60 h to 24 h. • The VS degradation efficiency was increased from 75.7% to 82.1%. - Abstract: Microalgae have been considered as one of the most promising biomass for the generation of biofuels. The anaerobic digestion (AD) has been proved to be a promising technique to transfer the microalgal biomass into biofuels. Previous study demonstrated that anaerobic pretreatment of microalgae biomass by Bacillus licheniformis could improve methane production. In this study micro-aerobic bio-pretreatment of microalgal biomass by the facultative anaerobic bacteria Bacillus licheniformis was invested with different loads of oxygen supplied. The bio-hydrogen and biomethane productions were tested to calculate total energy outcomes. The transmission electron microscope (TEM) photographs suggested that the novel micro-aerobic bio-pretreatment (MBP) could effectively damage the firm cell wall of algal cells. The processing time of the novel method (24 h) was less than the previous anaerobic pretreatment (60 h). Results showed that the group with 5 mL oxygen/g VS fed had the highest total energy outcomes, which was 17.6% higher than that of the anaerobic pretreatment.

76 FR 69136 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

Science.gov (United States)

2011-11-08

... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide; Correction. SUMMARY: The... Administrative Stay of the reporting requirements for hydrogen sulfide. The Office of the Federal Register...

Toxicity of zero-valent iron nanoparticles to a trichloroethylene-degrading groundwater microbial community.

Science.gov (United States)

Zabetakis, Kara M; Niño de Guzmán, Gabriela T; Torrents, Alba; Yarwood, Stephanie

2015-01-01

The microbiological impact of zero-valent iron used in the remediation of groundwater was investigated by exposing a trichloroethylene-degrading anaerobic microbial community to two types of iron nanoparticles. Changes in total bacterial and archaeal population numbers were analyzed using qPCR and were compared to results from a blank and negative control to assess for microbial toxicity. Additionally, the results were compared to those of samples exposed to silver nanoparticles and iron filings in an attempt to discern the source of toxicity. Statistical analysis revealed that the three different iron treatments were equally toxic to the total bacteria and archaea populations, as compared with the controls. Conversely, the silver nanoparticles had a limited statistical impact when compared to the controls and increased the microbial populations in some instances. Therefore, the findings suggest that zero-valent iron toxicity does not result from a unique nanoparticle-based effect.

Toxicity and utilization of chemical weapons: does toxicity and venom utilization contribute to the formation of species communities?

Science.gov (United States)

Westermann, Fabian L; McPherson, Iain S; Jones, Tappey H; Milicich, Lesley; Lester, Philip J

2015-08-01

Toxicity and the utilization of venom are essential features in the ecology of many animal species and have been hypothesized to be important factors contributing to the assembly of communities through competitive interactions. Ants of the genus Monomorium utilize a variety of venom compositions, which have been reported to give them a competitive advantage. Here, we investigate two pairs of Monomorium species, which differ in the structural compositions of their venom and their co-occurrence patterns with the invasive Argentine ant. We looked at the effects of Monomorium venom toxicity, venom utilization, and aggressive physical interactions on Monomorium and Argentine ant survival rates during arena trials. The venom toxicity of the two species co-occurring with the invasive Argentine ants was found to be significantly higher than the toxicity of the two species which do not. There was no correlation between venom toxicity and Monomorium survival; however, three of the four Monomorium species displayed significant variability in their venom usage which was associated with the number of Argentine ant workers encountered during trials. Average Monomorium mortality varied significantly between species, and in Monomorium smithii and Monomorium antipodum, aggressive interactions with Argentine ants had a significant negative effect on their mortality. Our study demonstrates that different factors and strategies can contribute to the ability of a species to withstand the pressure of a dominant invader at high abundance, and venom chemistry appears to be only one of several strategies utilized.

Molecular characterization of two microalgal strains in Egypt and investigation of the antimicrobial activity of their extracts

Directory of Open Access Journals (Sweden)

El Semary, NA.

2013-01-01

Full Text Available The emergence of new pathogens and the increasing drug-resistance of recognized ones pose a difficult challenge. One way that this challenge is being addressed is through the discovery of new cost-effective drug resources in the form of bioactive compounds. Algae represent a promising source of bioactive compounds in this regard. In the present research, we used molecular and phylogenetic analysis to isolate and identify two microalgal strains. We found that one strain belonged to the phylum chrysophyta and the other to the cyanobacteria. We also investigated the antimicrobial activity of some of the lipophilic extracts of the two microalgal strains. Several fractions showed high individual antimicrobial bioactivity against multidrug-resistant Salmonella sp., Citrobacter sp., Aspergillus niger and Aspergillus flavus. Fraction III from Poterioochromonas malhamensis showed the highest level of activity against two multidrug-resistant bacterial pathogens. The inhibition zone diameter was 1.4 cm for Salmonella and 1.4 cm for Citrobacter. Meanwhile, another lipophilic fraction from the cyanobacterium Synechocystis salina showed broad-spectrum bioactivity (inhibition zone diameter of 0.9 cm for Aspergillus niger, 1 cm for Citrobacter and 0.9 cm for Salmonella. One lipophilic fraction from Aphanizomenon showed antifungal bioactivity against Aspergillus niger and Aspergillus flavus, where the inhibition zone diameter was 1.1 cm and 1.0 cm, respectively. The study highlights the antimicrobial bioactivity of extracts from local microalgae and emphasizes the importance of carrying out screening programs for those microorganisms.

Toxic releases from power plants

International Nuclear Information System (INIS)

Rubin, E.S.

1999-01-01

Beginning in 1998, electric power plants burning coal or oil must estimate and report their annual releases of toxic chemicals listed in the Toxics Release Inventory (TRI) published by the US Environmental Protection Agency (EPA). This paper identifies the toxic chemicals of greatest significance for the electric utility sector and develops quantitative estimates of the toxic releases reportable to the TRI for a representative coal-fired power plant. Key factors affecting the magnitude and types of toxic releases for individual power plants also are discussed. A national projection suggests that the magnitude of electric utility industry releases will surpass those of the manufacturing industries which current report to the TRI. Risk communication activities at the community level will be essential to interpret and provide context for the new TRI results

Growth and metabolic characteristics of oleaginous microalgal isolates from Nilgiri biosphere Reserve of India.

Science.gov (United States)

Thangavel, Kalaiselvi; Radha Krishnan, Preethi; Nagaiah, Srimeena; Kuppusamy, Senthil; Chinnasamy, Senthil; Rajadorai, Jude Sudhagar; Nellaiappan Olaganathan, Gopal; Dananjeyan, Balachandar

2018-01-03

Renewable energy for sustainable development is a subject of a worldwide debate since continuous utilization of non-renewable energy sources has a drastic impact on the environment and economy; a search for alternative energy resources is indispensable. Microalgae are promising and potential alternate energy resources for biodiesel production. Thus, our efforts were focused on surveying the natural diversity of microalgae for the production of biodiesel. The present study aimed at identification, isolation, and characterization of oleaginous microalgae from shola forests of Nilgiri Biosphere Reserve (NBR), the biodiversity hot spot of India, where the microalgal diversity has not yet been systematically investigated. Overall the higher biomass yield, higher lipid accumulation and thermotolerance observed in the isolated microalgal strains have been found to be the desirable traits for the efficient biodiesel production. Species composition and diversity analysis yielded ten potential microalgal isolates belonging to Chlorophyceae and Cyanophyceae classes. The chlorophytes exhibited higher growth rate, maximum biomass yield, and higher lipid accumulation than Cyanophyceae. Among the chlorophytes, the best performing strains were identified and represented by Acutodesmus dissociatus (TGA1), Chlorella sp. (TGA2), Chlamydomonadales sp. (TGA3) and Hindakia tetrachotoma (PGA1). The Chlamydomonadales sp. recorded with the highest growth rate, lipid accumulation and biomass yield of 0.28 ± 0.03 day -1 (μ exp ), 29.7 ± 0.69% and 134.17 ± 16.87 mg L -1  day -1 , respectively. It was also found to grow well at various temperatures, viz., 25 °C, 35 °C, and 45 °C, indicating its suitability for open pond cultivation. The fatty acid methyl ester (FAME) analysis of stationary phase cultures of selected four algal strains by tandem mass spectrograph showed C16:0, C18:1 and C18:3 as dominant fatty acids suitable for biodiesel production. All the three

PSP toxin levels and plankton community composition and abundance in size-fractionated vertical profiles during spring/summer blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine and on Georges Bank, 2007, 2008, and 2010: 2. Plankton community composition and abundance.

Science.gov (United States)

Petitpas, Christian M; Turner, Jefferson T; Deeds, Jonathan R; Keafer, Bruce A; McGillicuddy, Dennis J; Milligan, Peter J; Shue, Vangie; White, Kevin D; Anderson, Donald M

2014-05-01

As part of the Gulf of Maine Toxicity (GOMTOX) project, we determined Alexandrium fundyense abundance, paralytic shellfish poisoning (PSP) toxin levels in various plankton size fractions, and the community composition of potential grazers of A. fundyense in plankton size fractions during blooms of this toxic dinoflagellate in the coastal Gulf of Maine and on Georges Bank in spring and summer of 2007, 2008, and 2010. PSP toxins and A. fundyense cells were found throughout the sampled water column (down to 50 m) in the 20-64 μm size fractions. While PSP toxins were widespread throughout all size classes of the zooplankton grazing community, the majority of the toxin was measured in the 20-64 μm size fraction. A. fundyense cellular toxin content estimated from field samples was significantly higher in the coastal Gulf of Maine than on Georges Bank. Most samples containing PSP toxins in the present study had diverse assemblages of grazers. However, some samples clearly suggested PSP toxin accumulation in several different grazer taxa including tintinnids, heterotrophic dinoflagellates of the genus Protoperidinium , barnacle nauplii, the harpacticoid copepod Microsetella norvegica , the calanoid copepods Calanus finmarchicus and Pseudocalanus spp., the marine cladoceran Evadne nordmanni , and hydroids of the genus Clytia . Thus, a diverse assemblage of zooplankton grazers accumulated PSP toxins through food-web interactions. This raises the question of whether PSP toxins pose a potential human health risk not only from nearshore bivalve shellfish, but also potentially from fish and other upper-level consumers in zooplankton-based pelagic food webs.

Toxic shock syndrome due to community-acquired methicillin-resistant Staphylococcus aureus infection: Two case reports and a literature review in Japan

OpenAIRE

Sada, Ryuichi; Fukuda, Saori; Ishimaru, Hiroyasu

2017-01-01

Community-acquired methicillin-resistant Staphylococcus aureus has been spreading worldwide, including in Japan. However, few cases of toxic shock syndrome caused by Community-acquired methicillin-resistant Staphylococcus aureus have been reported in Japan. We report 2 cases, in middle-aged women, of toxic shock syndrome due to Community-acquired methicillin-resistant Staphylococcus aureus via a vaginal portal of entry. The first patient had used a tampon and the second patient had vaginitis ...

2015 TRI National Analysis: Toxics Release Inventory Releases at Various Summary Levels

Data.gov (United States)

U.S. Environmental Protection Agency — The TRI National Analysis is EPA's annual interpretation of TRI data at various summary levels. It highlights how toxic chemical wastes were managed, where toxic...

Direct measurement and characterization of active photosynthesis zones inside biofuel producing and wastewater remediating microalgal biofilms

Energy Technology Data Exchange (ETDEWEB)

Bernstein, Hans C.; Kesaano, Maureen; Moll, Karen; Smith, Terence; Gerlach, Robin; Carlson, Ross; Miller, Charles D.; Peyton, Brent; Cooksey, Keith; Gardner, Robert D.; Sims, Ronald C.

2014-03-01

Abstract: Microalgal biofilm based technologies are of keen interest due to their high biomass concentrations and ability to utilize renewable resources, such as light and CO2. While photoautotrophic biofilms have long been used for wastewater remediation applications, biofuel production represents a relatively new and under-represented focus area. However, the direct measurement and characterization of fundamental parameters required for physiological analyses are challenging due to biofilm heterogeneity. This study evaluated oxygenic photosynthesis and biofuel precursor molecule production using a novel rotating algal biofilm reactor (RABR) operated at field- and laboratory-scales for wastewater remediation and biofuel production, respectively. Clear differences in oxygenic-photosynthesis, respiration and biofuel-precursor capacities were observed between the two systems and different conditions based on light and nitrogen availability. Nitrogen depletion was not found to have the same effect on lipid accumulation compared to prior planktonic studies. Physiological characterizations of these microalgal biofilms identify potential areas for future process optimization.

Effect of solvents and oil content on direct transesterification of wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized lipase as the biocatalyst.

Science.gov (United States)

Tran, Dang-Thuan; Chen, Ching-Lung; Chang, Jo-Shu

2013-05-01

In this work, a one-step extraction/transesterification process was developed to directly convert wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 into biodiesel using immobilized Burkholderia lipase as the catalyst. The microalgal biomass (water content of 86-91%; oil content 14-63%) was pre-treated by sonication to disrupt the cell walls and then directly mixed with methanol and solvent to carry out the enzymatic transesterification. Addition of a sufficient amount of solvent (hexane is most preferable) is required for the direct transesterification of wet microalgal biomass, as a hexane-to-methanol mass ratio of 1.65 was found optimal for the biodiesel conversion. The amount of methanol and hexane required for the direct transesterification process was also found to correlate with the lipid content of the microalga. The biodiesel synthesis process was more efficient and economic when the lipid content of the microalgal biomass was higher. Therefore, using high-lipid-content microalgae as feedstock appears to be desirable. Copyright © 2012 Elsevier Ltd. All rights reserved.

A novel one-stage cultivation/fermentation strategy for improved biogas production with microalgal biomass.

Science.gov (United States)

Klassen, Viktor; Blifernez-Klassen, Olga; Hoekzema, Yoep; Mussgnug, Jan H; Kruse, Olaf

2015-12-10

The use of alga biomass for biogas generation has been studied for over fifty years but until today, several distinct features, like inefficient degradation and low C/N ratios, limit the applicability of algal biomass for biogas production in larger scale. In this work we investigated a novel, one-stage combined cultivation/fermentation strategy including inherently progressing nitrogen starvation conditions to generate improved microalgal biomass substrates. For this strategy, comparable low amounts of nitrogen fertilizers were applied during cultivation and no additional enzymatic, chemical or physical pretreatments had to be performed. The results of this study demonstrate that progressing nitrogen limitation leads to continuously increasing C/N ratios of the biomass up to levels of 24-26 for all three tested alga strains (Chlamydomonas reinhardtii, Parachlorella kessleri and Scenedesmus obliquus). Importantly, the degradation efficiency of the algal cells increased with progressing starvation, leading to strain-specific cell disintegration efficiencies of 35%-100% during the fermentation process. Nitrogen limitation treatment resulted in a 65% increase of biogas yields for C. reinhardtii biomass (max. 698±23mL biogas g(-1) VS) when compared to replete conditions. For P. kessleri and S. obliquus, yields increased by 94% and 106% (max. 706±39mL and 586±36mL biogas g(-1) VS, respectively). From these results we conclude that this novel one-stage cultivation strategy with inherent nitrogen limitation can be used as a pretreatment for microalgal biomass generation, in order to produce accessible substrates with optimized C/N ratios for the subsequent anaerobic fermentation process, thus increasing methane production and avoiding the risk of ammonia inhibition effects within the fermenter. Copyright © 2015 Elsevier B.V. All rights reserved.

LEVEL OF TOXICITY WATER AREA «TULENIY» AS A RESULT OF BIOASSAY

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A. F. Sokolsky

2014-01-01

Full Text Available Aim. To determine the toxicity of marine waters area " tuleniy ".Location. Area " tuleniy ".Methods. Determining the level of toxicity of marine waters area "seal" method for biological testing was conducted according tothe guidelines approved by the Ministry of natural resources (guidance on the definition of ..., 2002; Dolzhenko, 1978. Guide prepared by the Center for Russian register of hydraulic structures and the state water cadastre of the MNR of Russia jointly with specialists of the Institute Committee of Russia and the UNION of ecological problems of the Ministry of Ukraine. The basis of the proposed system of marine toxicity biotests based on the results of generalization of experimental research based on the problem of pollution of water bodies and numerous literature data, making it possible to identify features of the response of aquatic organisms of different taxonomic groups to toxic impurities of different nature and origin. Experimental studies were conducted on the culture of marine unicellular algae Phaeodactylum tricornutum on planktonic crustacea Acartia tonsa, the larvae of the chironomid Chironomus gr.salinarius and juvenile guppies Poecillia reticulata Peters.Results. Comparative analysis of the results of research from 2001 to 2006 showed no acute toxic effect on the test object zooplankton and phytoplanton.Main conclusions. Throughout the study period (2001-2003, 2005-2006, you must allocate the spring of 2002, when it was recorded,the average of the lowest five years of research, the level of toxicity of water for the analyzed area.Considering the results of biological testing of the surveyed area by periods, it should be noted that the average level of toxicity of the waters did not undergo significant changes and were on the same level, not exceeding 17,6% (table. 1. According to the classification shown in table 2, the water in the surveyed area is assessed as "non-toxic".

Toxic shock syndrome due to community-acquired methicillin-resistant Staphylococcus aureus infection: Two case reports and a literature review in Japan.

Science.gov (United States)

Sada, Ryuichi; Fukuda, Saori; Ishimaru, Hiroyasu

2017-01-01

Community-acquired methicillin-resistant Staphylococcus aureus has been spreading worldwide, including in Japan. However, few cases of toxic shock syndrome caused by Community-acquired methicillin-resistant Staphylococcus aureus have been reported in Japan. We report 2 cases, in middle-aged women, of toxic shock syndrome due to Community-acquired methicillin-resistant Staphylococcus aureus via a vaginal portal of entry. The first patient had used a tampon and the second patient had vaginitis due to a cleft narrowing associated with vulvar lichen sclerosus. Both patients were admitted to our hospital with septic shock and severe acute kidney injury and subsequently recovered with appropriate antibiotic treatment. In our review of the literature, 8 cases of toxic shock syndrome caused by Community-acquired methicillin-resistant Staphylococcus aureus were reported in Japan. In these 8 cases, the main portals of entry were the skin and respiratory tract; however, the portal of entry of Community-acquired methicillin-resistant Staphylococcus aureus from a vaginal lesion has not been reported in Japan previously.

Perceptions of environmental health risks among residents in the "Toxic Doughnut": opportunities for risk screening and community mobilization.

Science.gov (United States)

White, Brandi M; Hall, Eric S

2015-12-10

Surrounded by landfills, and toxic and hazardous facilities, Altgeld Gardens is located in a "toxic doughnut". With high rates of environmentally-related conditions, residents have called for a community-based environmental health assessment to improve overall health in their community. The purpose of this study was to investigate the attitudes and beliefs of environmental health risks of Altgeld's residents which would assist community organizing efforts and provide the groundwork for a community-based environmental health assessment. A questionnaire was designed and administered to 42 Altgeld residents who also participated in focus groups to assess their perceptions of environmental health risks. All participants were Altgeld residents for at least two years and were fairly representative of the broader community. Physical and social hazards were primarily identified as posing risks to participants' family and the broader community. Physical hazards included the dumping of hazardous waste and landfills; social hazards were crime and drugs. These findings have been useful in community organizing efforts and in program planning for local community-based organizations and public health agencies. The results have also been used to prioritize health and environmental risk issues impacting the community.

Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula

Directory of Open Access Journals (Sweden)

Ariela Burg

2015-10-01

Full Text Available Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides’ antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains’ interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca2+ had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides’ stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.

Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula.

Science.gov (United States)

Burg, Ariela; Oshrat, Levy-Ontman

2015-10-20

Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides' antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains' interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca(2+) had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides' stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.

Broad-Scale Comparison of Photosynthesis in Terrestrial and Aquatic Plant Communities

DEFF Research Database (Denmark)

Sand-Jensen, Kaj; Krause-Jensen, D.

1997-01-01

Comparisons of photosynthesis in terrestrial and aquatic habitats have been impaired by differences in methods and time-scales of measurements. We compiled information on gross photosynthesis at high irradiance and photosynthetic efficiency at low irradiance from 109 published terrestrial studies...... communities probably due to more efficient light utilization and gas exchange in the terrestrial habitats. By contrast only small differences were found within different aquatic plant communities or within different terrestrial plant communities....... of forests, grasslands and crops and 319 aquatic studies of phytoplankton, macrophyte and attached microalgal communities to test if specific differences existed between the communities. Maximum gross photosynthesis and photosynthetic efficiency were systematically higher in terrestrial than in aquatic...

Microalgal technology for remediation of CO{sub 2} from power plant flue gas: A technoeconomic perspective

Energy Technology Data Exchange (ETDEWEB)

Kadam, K.L.; Sheehan, J.J. [National Renewable Energy Lab., Golden, CO (United States). Biotechnology Center for Fuels and Chemicals

1996-12-01

Power plants burning fossil fuels are a major source of CO{sub 2}, which is implicated in global warming. Microalgal systems, which photosynthetically assimilate CO{sub 2}, can be used to mitigate this major greenhouse gas. A technoeconomic model was developed for trapping CO{sub 2} from flue gases by microalgae in outdoor ponds. The model allows the authors to make some notable observations about the microalgal process. For example, although it was known that the delivered CO{sub 2} cost is an important parameter, this model demonstrates in quantitative terms that the targeted improvements for productivity and lipid content double the relative impact of CO{sub 2} resource cost on total annualized cost of the technology. The model also shows that both algal lipid content and growth rate are important for an economical process, but a trade-off exists between the two, i.e., a high lipid content and low growth rate combination can be as effective as a low lipid content and high growth rate combination. Model predictions were also used to compare the microalgal technology with alternative technologies in terms of CO{sub 2} mitigation costs. The mid-term process, which can be implemented in the near future, is competitive with other CO{sub 2} remediation technologies currently being proposed. Incorporating anticipated advances into the design basis, a CO{sub 2} mitigation cost of $30/t (CO{sub 2} avoided basis) is obtained for the long-term process, which is very promising. Deployment of this technology for CO{sub 2} mitigation looks attractive if research goals put forth by the model are achieved.

Isolation and Selection of Microalgal Strains from Natural Water Sources in Viet Nam with Potential for Edible Oil Production.

Science.gov (United States)

Thao, Tran Yen; Linh, Dinh Thi Nhat; Si, Vo Chi; Carter, Taylor W; Hill, Russell T

2017-06-23

Industrial vegetable oil production in Viet Nam depends on oil seeds and crude plant oils that are currently more than 90% imported. As the first step in investigating the feasibility of using microalgae to provide Viet Nam with a domestic source of oil for food and edible oil industries, fifty lipid-producing microalgae were isolated and characterized. The microalgae were isolated from water sources ranging from freshwater to brackish and marine waters from a wide geographic distribution in Viet Nam. Initial analyses showed that 20 of the 50 strains had good growth rates, produced high biomass and had high lipid content, ranging up to 50% of dry weight biomass. 18S rRNA gene sequence analyses of the 50 strains showed a great diversity in this assemblage of microalgae, comprising at least 38 species and representatives of 25 genera : Chlamydomonas , Poterioochromonas , Scenedesmus , Desmodesmus , Chlorella , Bracteacoccus , Monoraphidium , Selenastrum , Acutodesmus , Mychonastes , Ankistrodesmus , Kirchneriella , Raphidocelis , Dictyosphaerium , Coelastrella , Schizochlamydella , Oocystidium , Nannochloris , Auxenochlorella , Chlorosarcinopsis , Stichococcus , Picochlorum , Prasinoderma , Chlorococcum , and Marvania. Some of the species are closely related to well-known lipid producers such as Chlorella sorokiniana , but some other strains are not closely related to the strains found in public sequence databases and likely represent new species. Analysis of oil quality showed that fatty acid profiles of the microalgal strains were very diverse and strain-dependent. Fatty acids in the microalgal oils comprised saturated fatty acids (SFAs), poly-unsaturated fatty acids (PUFAs), and mono-unsaturated fatty acids (MUFAs). The main SFA was palmitic acid. MUFAs and PUFAs were dominated by oleic acid, and linoleic and linolenic acids, respectively. Some strains were especially rich in the essential fatty acid α-linolenic acid (ALA), which comprised more than 20% of the

Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms".

Directory of Open Access Journals (Sweden)

Cristiana Callieri

Full Text Available Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena, a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.

Management of low and intermediate level radioactive wastes with regard to their chemical toxicity

International Nuclear Information System (INIS)

2002-12-01

A preliminary overview is provided of management options for low and intermediate level radioactive waste (LILW) with regard to its chemical toxicity. In particular, the following issues are identified and described associated with the management and safe disposal of chemically toxic materials in LILW: the origin and characteristics; the regulatory approaches; the pre-disposal management; the disposal; the safety assessment. Also included are: regulatory framework for chemically toxic low level wastes in the USA; pre-disposal processing options for LILW containing chemically toxic components; example treatment technologies for LILW containing chemically toxic components and safety assessment case studies for Germany, Belgium, France and Sweden

Detailing the start-up and microalgal growth performance of a full-scale photobioreactor operated with bioindustrial wastewater

DEFF Research Database (Denmark)

Podevin, Michael Paul Ambrose; Fotidis, Ioannis; De Francisci, Davide

2017-01-01

were tested. Bioindustrial WW medium was treated with ultrafiltration and was demonstrated to be a viable microalgal growth medium at large scale; however, further treatment is needed for the removal of fecal coliform to meet drinking water standards. The fresh water mesophilic algae Chlorella...

Acclimation to extremely high ammonia levels in continuous biomethanation process and the associated microbial community dynamics

DEFF Research Database (Denmark)

Tian, Hailin; Fotidis, Ioannis; Mancini, Enrico

2018-01-01

Acclimatized anaerobic communities to high ammonia levels can offer a solution to the ammonia toxicity problem in biogas reactors. In the current study, a stepwise acclimation strategy up to 10 g NH4+-N L−1, was performed in mesophilic (37 ± 1 °C) continuously stirred tank reactors. The reactors...... change throughout the ammonia acclimation process. Clostridium ultunense, a syntrophic acetate oxidizing bacteria, increased significantly alongside with hydrogenotrophic methanogen Methanoculleus spp., indicating strong hydrogenotrophic methanogenic activity at extreme ammonia levels (>7 g NH4+-N L−1...

Minimising losses to predation during microalgae cultivation.

Science.gov (United States)

Flynn, Kevin J; Kenny, Philip; Mitra, Aditee

2017-01-01

We explore approaches to minimise impacts of zooplanktonic pests upon commercial microalgal crops using system dynamics models to describe algal growth controlled by light and nutrient availability and zooplankton growth controlled by crop abundance and nutritional quality. Losses of microalgal crops are minimised when their growth is fastest and, in contrast, also when growing slowly under conditions of nutrient exhaustion. In many culture systems, however, dwindling light availability due to self-shading in dense suspensions favours slow growth under nutrient sufficiency. Such a situation improves microalgal quality as prey, enhancing zooplankton growth, and leads to rapid crop collapse. Timing of pest entry is important; crop losses are least likely in established, nutrient-exhausted microalgal communities grown for high C-content (e.g. for biofuels). A potentially useful approach is to promote a low level of P-stress that does not adversely affect microalgal growth but which produces a crop that is suboptimal for zooplankton growth.

Extraction of microalgal lipids and the influence of polar lipids on biodiesel production by lipase-catalyzed transesterification.

Science.gov (United States)

Navarro López, Elvira; Robles Medina, Alfonso; González Moreno, Pedro Antonio; Esteban Cerdán, Luis; Molina Grima, Emilio

2016-09-01

In order to obtain microalgal saponifiable lipids (SLs) fractions containing different polar lipid (glycolipids and phospholipids) contents, SLs were extracted from wet Nannochloropsis gaditana microalgal biomass using seven extraction systems, and the polar lipid contents of some fractions were reduced by low temperature acetone crystallization. We observed that the polar lipid content in the extracted lipids depended on the polarity of the first solvent used in the extraction system. Lipid fractions with polar lipid contents between 75.1% and 15.3% were obtained. Some of these fractions were transformed into fatty acid methyl esters (FAMEs, biodiesel) by methanolysis, catalyzed by the lipases Novozym 435 and Rhizopus oryzae in tert-butanol medium. We observed that the reaction velocity was higher the lower the polar lipid content, and that the final FAME conversions achieved after using the same lipase batch to catalyze consecutive reactions decreased in relation to an increase in the polar lipid content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Three-Dimensional Simulation of Ultrasound-Induced Microalgal Cell Disruption.

Science.gov (United States)

Wang, M; Yuan, W; Hale, Andy

2016-03-01

The three-dimensional distribution (x, y, and z) of ultrasound-induced microalgal cell disruption in a sonochemical reactor was predicted by solving the Helmholtz equation using a three-dimensional acoustic module in the COMSOL Multiphysics software. The simulated local ultrasound pressure at any given location (x, y, and z) was found to correlate with cell disruption of a freshwater alga, Scenedesmus dimorphus, represented by the change of algal cell particle/debris concentration, chlorophyll-a fluorescence density (CAFD), and Nile red stained lipid fluorescence density (LFD), which was also validated by the model reaction of potassium iodide oxidation (the Weissler reaction). Furthermore, the effect of ultrasound power intensity and processing duration on algal cell disruption was examined to address the limitation of the model.

Effects of toxic cyanobacteria on plankton assemblage : community development during decay of Nodularia spumigena

DEFF Research Database (Denmark)

Engström-Öst, J.; Koski, Marja; Schmidt, K.

2002-01-01

We studied the development of the plankton community in an artificially created toxic Nodularia spumigena bloom during a 2 wk enclosure study at the SW coast of Finland in the Baltic Sea. We measured bacterial abundance, dominant phytoplankton groups and ciliates, as well as concentrations of phy...

Microalgal process-monitoring based on high-selectivity spectroscopy tools: status and future perspectives.

Science.gov (United States)

Podevin, Michael; Fotidis, Ioannis A; Angelidaki, Irini

2018-08-01

Microalgae are well known for their ability to accumulate lipids intracellularly, which can be used for biofuels and mitigate CO 2 emissions. However, due to economic challenges, microalgae bioprocesses have maneuvered towards the simultaneous production of food, feed, fuel, and various high-value chemicals in a biorefinery concept. On-line and in-line monitoring of macromolecules such as lipids, proteins, carbohydrates, and high-value pigments will be more critical to maintain product quality and consistency for downstream processing in a biorefinery to maintain and valorize these markets. The main contribution of this review is to present current and prospective advances of on-line and in-line process analytical technology (PAT), with high-selectivity - the capability of monitoring several analytes simultaneously - in the interest of improving product quality, productivity, and process automation of a microalgal biorefinery. The high-selectivity PAT under consideration are mid-infrared (MIR), near-infrared (NIR), and Raman vibrational spectroscopies. The current review contains a critical assessment of these technologies in the context of recent advances in software and hardware in order to move microalgae production towards process automation through multivariate process control (MVPC) and software sensors trained on "big data". The paper will also include a comprehensive overview of off-line implementations of vibrational spectroscopy in microalgal research as it pertains to spectral interpretation and process automation to aid and motivate development.

State-Level Community Benefit Regulation and Nonprofit Hospitals' Provision of Community Benefits.

Science.gov (United States)

Singh, Simone R; Young, Gary J; Loomer, Lacey; Madison, Kristin

2018-04-01

Do nonprofit hospitals provide enough community benefits to justify their tax exemptions? States have sought to enhance nonprofit hospitals' accountability and oversight through regulation, including requirements to report community benefits, conduct community health needs assessments, provide minimum levels of community benefits, and adhere to minimum income eligibility standards for charity care. However, little research has assessed these regulations' impact on community benefits. Using 2009-11 Internal Revenue Service data on community benefit spending for more than eighteen hundred hospitals and the Hilltop Institute's data on community benefit regulation, we investigated the relationship between these four types of regulation and the level and types of hospital-provided community benefits. Our multivariate regression analyses showed that only community health needs assessments were consistently associated with greater community benefit spending. The results for reporting and minimum spending requirements were mixed, while minimum income eligibility standards for charity care were unrelated to community benefit spending. State adoption of multiple types of regulation was consistently associated with higher levels of hospital-provided community benefits, possibly because regulatory intensity conveys a strong signal to the hospital community that more spending is expected. This study can inform efforts to design regulations that will encourage hospitals to provide community benefits consistent with policy makers' goals. Copyright © 2018 by Duke University Press.

Individual- and community-level social gradients of edentulousness.

Science.gov (United States)

Ito, Kanade; Aida, Jun; Yamamoto, Tatsuo; Ohtsuka, Rika; Nakade, Miyo; Suzuki, Kayo; Kondo, Katsunori; Osaka, Ken

2015-03-11

Community-level factors as well as individual-level factors affect individual health. To date, no studies have examined the association between community-level social gradient and edentulousness. The aim of this study was to investigate individual- and community-level social inequalities in edentulousness and to determine any explanatory factors in this association. We analyzed the data from the Japan Gerontological Evaluation Study (JAGES). In 2010-2012, 112,123 subjects aged 65 or older responded to the questionnaire survey (response rate = 66.3%). Multilevel logistic regression analysis was applied to determine the association between community-level income and edentulousness after accounting for individual-level income and demographic covariates. Then, we estimated the probability of edentulousness by individual- and community-level incomes after adjusted for covariates. Of 79,563 valid participants, the prevalence of edentulousness among 39,550 men (49.7%) and 40,013 women (50.3%) were both 13.8%. Living in communities with higher mean incomes and having higher individual-level incomes were significantly associated with a lower risk of edentulousness (odds ratios [ORs] by 10,000 USD increments were 0.37 (95% confidence interval [CI] [0.22-0.63]) for community-level and 0.85 (95% CI [0.84-0.86]) for individual-level income). Individual- and community-level social factors, including density of dental clinics, partially explained the social gradients. However, in the fully adjusted model, both community- and individual-level social gradients of edentulousness remained significant (ORs = 0.43 (95% CI [0.27-0.67]) and 0.90 (95% CI [0.88-0.91]), respectively). One standard deviation changes in community- and individual-level incomes were associated with 0.78 and 0.84 times lower odds of edentulousness, respectively. In addition, compared to men, women living in communities with higher average incomes had a significantly lower risk of edentulousness (p-value for

FY1995 microalgal biotechnology for recycling of pollutants; 1995 nendo tayona sorui kino wo kiban to suru seibutsuken busshitsu junkangta sogo saishigenka gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The objectives are 1) development of biological processes needed for the treatment of pollutants and the conversion of resulting biomass to value added products such as energy and fine chemicals, and 2) development of techniques for monitoring of both biological and chemical hazards associated with process operation. We developed a microalgal system for simultaneous removal of CO{sub 2}/NO{sub x} from flue gas, as well as an electro-osmotic method for recovery of microalgal cells. A strategy for effective culturing of photoautotrophic cells in photobioreactors was also proposed. We utilized waste algal biomass to produce biosurfactants, and studied about structure-function relationship of lipopeptide biosurfactants. As an energy product, H{sub 2} was produced via lactic acid fermentation of algal biomass. Physiology of marine phytoplankton was also studied in relation to the future mass production of microalgal biomass. A rapid monitoring of microbial populations was possible by using fluorescent probes. An enzyme immunosorbent assay system specific to fish metallothionein was established for the assessment of aquatic environmental pollution. Human herpesvirus latent infection was effectively applied to biological assay of environmental hygiene. (NEDO)

Microalgal bioengineering for sustainable energy development: Recent transgenesis and metabolic engineering strategies.

Science.gov (United States)

Banerjee, Chiranjib; Singh, Puneet Kumar; Shukla, Pratyoosh

2016-03-01

Exploring the efficiency of algae to produce remarkable products can be directly benefitted by studying its mechanism at systems level. Recent advents in biotechnology like flux balance analysis (FBA), genomics and in silico proteomics minimize the wet lab exertion. It is understood that FBA predicts the metabolic products, metabolic pathways and alternative pathway to maximize the desired product, and these are key components for microalgae bio-engineering. This review encompasses recent transgenesis techniques and metabolic engineering strategies applied to different microalgae for improving different traits. Further it also throws light on RNAi and riboswitch engineering based methods which may be advantageous for high throughput microalgal research. A valid and optimally designed microalga can be developed where every engineering strategies meet each other successfully and will definitely fulfill the market needs. It is also to be noted that Omics (viz. genetic and metabolic manipulation with bioinformatics) should be integrated to develop a strain which could prove to be a futuristic solution for sustainable development for energy. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment and application of national environmental databases and mapping tools at the local level to two community case studies.

Science.gov (United States)

Hammond, Davyda; Conlon, Kathryn; Barzyk, Timothy; Chahine, Teresa; Zartarian, Valerie; Schultz, Brad

2011-03-01

Communities are concerned over pollution levels and seek methods to systematically identify and prioritize the environmental stressors in their communities. Geographic information system (GIS) maps of environmental information can be useful tools for communities in their assessment of environmental-pollution-related risks. Databases and mapping tools that supply community-level estimates of ambient concentrations of hazardous pollutants, risk, and potential health impacts can provide relevant information for communities to understand, identify, and prioritize potential exposures and risk from multiple sources. An assessment of existing databases and mapping tools was conducted as part of this study to explore the utility of publicly available databases, and three of these databases were selected for use in a community-level GIS mapping application. Queried data from the U.S. EPA's National-Scale Air Toxics Assessment, Air Quality System, and National Emissions Inventory were mapped at the appropriate spatial and temporal resolutions for identifying risks of exposure to air pollutants in two communities. The maps combine monitored and model-simulated pollutant and health risk estimates, along with local survey results, to assist communities with the identification of potential exposure sources and pollution hot spots. Findings from this case study analysis will provide information to advance the development of new tools to assist communities with environmental risk assessments and hazard prioritization. © 2010 Society for Risk Analysis.

[Acute toxicity effects of three red tide algae on Brachionus plicatilis].

Science.gov (United States)

Zhou, Wen-Li; Xiao, Hui; Wang, You; Zhai, Hong-Chang; Tang, Xue-Xi

2008-11-01

Acute toxicity testing method was used to study effects of different density of Prorocentrum donghaiense, Heterosigma akashiwo and Alexandrium tamarense on mortality rates and population growth parameter of Brachionus plicatilis under controlled experimental conditions. Results showed that 24 h LC50 values of Prorocentrum donghaiense, Heterosigma akashiwo and Alexandrium tamarense treatment to mortality rate of Brachionus plicatilis were 3.56, 1.21 and 0.49 (x 10(4) cells/mL) respectively. Marked density effects were presented when three species of red tide microalga showed their toxicity to Brachionus plicatilis. There were significant inhibitory effects on Brachionus plicatilis when it was exposed to cells of Prorocentrum donghaiense at the concentration of 10(4) cells/mL, filtrate and cell contents of Heterosigma akashiwo at the concentration of 10(5) cells/mL, and cells, filtrate and cell contents of Alexandrium tamarense at the concentration of 10(3) cells/mL respectively. Inhibitory effects of three species of microalga on Brachionus plicatilis were enhanced with increasing of microalgal density.

Comparison of toxicity of class-based organic chemicals to algae and fish based on discrimination of excess toxicity from baseline level.

Science.gov (United States)

Li, Jin J; Tai, Hong W; Yu, Yang; Wen, Yang; Wang, Xiao H; Zhao, Yuan H

2015-07-01

Toxicity data to fish and algae were used to investigate excess toxicity between species. Results show that chemicals exhibiting excess toxicity to fish also show excess toxicity to algae for most of the compounds. This indicates that they share the same mode of action between species. Similar relationships between logKOW and toxicities to fish and algae for baseline and less inert compounds suggest that they have similar critical body residues in the two species. Differences in excess toxicity for some compounds suggest that there is a difference of physiological structure and metabolism between fish and algae. Some reactive compounds (e.g. polyamines) exhibit greater toxic effects for algae than those for fish because of relatively low bio-uptake potential of these hydrophilic compounds in fish as compared with that in algae. Esters exhibiting greater toxicity in fish than that in algae indicate that metabolism can affect the discrimination of excess toxicity from baseline level. Algae growth inhibition is a very good surrogate for fish lethality. This is not only because overall toxicity sensitivity to algae is greater than that to fish, but also the excess toxicity calculated from algal toxicity can better reflect reactivity of compounds with target molecules than fish toxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

A New, Sensitive Marine Microalgal Recombinant Biosensor Using Luminescence Monitoring for Toxicity Testing of Antifouling Biocides

Science.gov (United States)

Sanchez-Ferandin, Sophie; Leroy, Fanny; Bouget, François-Yves

2013-01-01

In this study, we propose the use of the marine green alga Ostreococcus tauri, the smallest free-living eukaryotic cell known to date, as a new luminescent biosensor for toxicity testing in the environment. Diuron and Irgarol 1051, two antifouling biocides commonly encountered in coastal waters, were chosen to test this new biosensor along with two degradation products of diuron. The effects of various concentrations of the antifoulants on four genetic constructs of O. tauri (based on genes involved in photosynthesis, cell cycle, and circadian clock) were compared using 96-well culture microplates and a luminometer to automatically measure luminescence over 3 days. This was compared to growth inhibition of O. tauri wild type under the same conditions. Luminescence appeared to be more sensitive than growth inhibition as an indicator of toxicity. Cyclin-dependent kinase (CDKA), a protein involved in the cell cycle, fused to luciferase (CDKA-Luc) was found to be the most sensitive of the biosensors, allowing an accurate determination of the 50% effective concentration (EC50) after only 2 days (diuron, 5.65 ± 0.44 μg/liter; Irgarol 1015, 0.76 ± 0.10 μg/liter). The effects of the antifoulants on the CDKA-Luc biosensor were then compared to growth inhibition in natural marine phytoplankton. The effective concentrations of diuron and Irgarol 1051 were found to be similar, indicating that this biosensor would be suitable as a reliable ecotoxicological test. The advantage of this biosensor over cell growth inhibition testing is that the process can be easily automated and could provide a high-throughput laboratory approach to perform short-term toxicity tests. The ability to genetically transform and culture recombinant O. tauri gives it huge potential for screening many other toxic compounds. PMID:23144143

Fluoranthene induced changes in photosynthetic pigments, biochemical compounds and enzymatic activities in two microalgal species: Chlorella vulgaris Beijerinck and Desmodesmus subspicatus Chodat

Directory of Open Access Journals (Sweden)

Miral Patel

2014-02-01

Full Text Available The photosynthetic pigments, biochemical and enzymatic activities in two freshwater microalgal species, Chlorella vulgaris and Desmodesmus subspicatus at different fluoranthene concentrations were compared with the control conditions. During 16-days of incubation period when treated with fluoranthene, both microalgal species exhibited variable amount of photosynthetic pigment, biochemical compounds and enzymatic activities. The addition of fluoranthene at concentrations ranged from 1.5 mg l-1; to 10 mg l-1; to microalgal cultures led to changes in all different metabolites but the patterns varied from species to species. Among the two species tested, pigment, biochemical and enzymatic contents were remarkably declined from 7 % to 95% in C. vulgaris. Moreover, all metabolites in D. subspicatus also diminishing significantly by 3% to 88% of fluoranthene doses (10ppm. These results suggest that fluoranthene-induced changes of pigments, biochemical and enzymatic variations in test microalgae, D. subspicatus and C. vulgaris, might reveal its resistance and ability to metabolize PAHs. At the same time, the PAH impact changes on different metabolic activities were higher at 12 and 16 days than at 4 and 8 days in treated microalgae. DOI: http://dx.doi.org/10.3126/ije.v3i1.9941 International Journal of Environment Vol.3(1 2014: 41-55

Assessing condition of macroinvertebrate communities and sediment toxicity in the St. Lawrence River at Massena Area-of-Concern

Science.gov (United States)

Duffy, Brian T.; Baldigo, Barry P.; Smith, Alexander J.; George, Scott D.; David, Anthony M.

2016-01-01

In 1972, the USA and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement. In subsequent amendments, part of the St. Lawrence River at Massena, New York and segments of three tributaries, were designated as an Area of Concern (AOC) due to the effects of polychlorinated biphenyls (PCBs), lead and copper contamination, and habitat degradation and resulting impairment to several beneficial uses. Because sediments have been largely remediated, the present study was initiated to evaluate the current status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate communities and sediment toxicity tests using Chironomus dilutus were used to test the hypotheses that community condition and sediment toxicity at AOC sites were not significantly different from those of adjacent reference sites. Grain size was found to be the main driver of community composition and macroinvertebrate assemblages, and bioassessment metrics did not differ significantly between AOC and reference sites of the same sediment class. Median growth of C. dilutus and its survival in three of the four river systems did not differ significantly in sediments from AOC and reference sites. Comparable macroinvertebrate assemblages and general lack of toxicity across most AOC and reference sites suggest that the quality of sediments should not significantly impair benthic macroinvertebrate communities in most sites in the St. Lawrence River AOC.

Adaptation of copper community tolerance levels after biofilm transplantation in an urban river.

Science.gov (United States)

Fechner, Lise C; Versace, François; Gourlay-Francé, Catherine; Tusseau-Vuillemin, Marie-Hélène

2012-01-15

The Water Framework Directive requires the development of biological tools which can act as early-warning indicators of a sudden increase (accidental pollution) or decrease (recovery due to prevention) of the chemical status of aquatic systems. River biofilms, which respond quickly to modifications of environmental parameters and also play a key part in the functioning of aquatic ecosystems, are therefore good candidates to monitor an increase or a decrease of water pollution. In the present study, we investigated the biological response of biofilms transplanted either upstream (recovery) or downstream (deterioration of exposure levels) the urban area of Paris (France). Both modifications of Cu community tolerance levels and of global bacterial and eukaryotic community structure using automated ribosomal intergenic spacer analysis (ARISA) fingerprints were examined 15 and 30 days after the transplantation. Cu tolerance levels of the heterotrophic component of biofilms were assessed using a short-term toxicity test based on β-glucosidase (heterotrophic) activity. Cu tolerance increased for biofilms transplanted upstream to downstream Paris (5-fold increase on day 30) and conversely decreased for biofilms transplanted downstream to upstream (8-fold decrease on day 30). ARISA fingerprints revealed that bacterial and eukaryotic community structures of transplanted biofilms were closer to the structures of biofilms from the transplantation sites (or sites with similar contamination levels) than to biofilms from their sites of origin. Statistical analysis of the data confirmed that the key factor explaining biofilm Cu tolerance levels is the sampling site and not the site of origin. It also showed that Cu tolerance levels are related to the global urban contamination (both metals and nutrients). The study shows that biofilms adapt fast to modifications of their surroundings. In particular, community tolerance varies quickly and reflects the new exposure levels only 15

Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine.

Science.gov (United States)

Parsaeimehr, Ali; Sun, Zhilan; Dou, Xiao; Chen, Yi-Feng

2015-01-01

Photoautotrophic microalgae are a promising avenue for sustained biodiesel production, but are compromised by low yields of biomass and lipids at present. We are developing a chemical approach to improve microalgal accumulation of feedstock lipids as well as high-value alpha-linolenic acid which in turn might provide a driving force for biodiesel production. We demonstrate the effectiveness of the small bioactive molecule "acetylcholine" on accumulation of biomass, total lipids, and alpha-linolenic acid in Chlorella sorokiniana. The effectiveness exists in different species of Chlorella. Moreover, the precursor and analogs of acetylcholine display increased effectiveness at higher applied doses, with maximal increases by 126, 80, and 60% over controls for biomass, total lipids, and alpha-linolenic acid, respectively. Production of calculated biodiesel was also improved by the precursor and analogs of acetylcholine. The biodiesel quality affected by changes in microalgal fatty acid composition was addressed. The chemical approach described here could improve the lipid yield and biodiesel production of photoautotrophic microalgae if combined with current genetic approaches.

Plasma citrulline levels predict intestinal toxicity in patients treated with pelvic radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Onal, Cem; Kotek, Ayse; Arslan, Gungor; Topkan, Erkan (Dept. of Radiation Oncology, Baskent Univ. Faculty of Medicine, Adana (Turkey)), E-mail: hcemonal@hotmail.com; Unal, Birsel (Dept. of Biochemistry, Baskent Univ. Faculty of Medicine, Ankara (Turkey)); Yavuz, Aydin; Yavuz, Melek (Dept. of Radiation Oncology, Akdeniz Univ. Faculty of Medicine, Antalya (Turkey))

2011-11-15

Background. Radiotherapy (RT) for abdominal and pelvic malignancies often causes severe small bowel toxicity. Citrulline concentrations are known to decrease with intestinal failure. We thus evaluated the feasibility of plasma citrulline levels in predicting radiation-induced intestinal toxicity. Material and methods. Fifty-three patients (36 prostate cancer, 17 endometrial cancer) who received 45 Gy pelvic RT using conventional fractionation were prospectively evaluated. Patients with prostate cancer received an additional 25-30.6 Gy conformal boost. Plasma citrulline levels were assessed on day 0, mid- (week 3) and post-RT (week 8), and four months post-RT. Dose-volume histogram, citrulline concentration changes, and weekly intestinal toxicity scores were analyzed. Results. Mean age was 63 years (range: 43-81 years) and mean baseline citrulline concentration was 38.0 +- 10.1 mumol/l. Citrulline concentrations were significantly reduced at week 3 (27.4 +- 5.9 mumol/l; p < 0.0001), treatment end (29.9 +- 8.8 mumol/l; p < 0.0001), and four months post-treatment (34.3 +- 12.1; p 0.01). The following factor pairs were significantly positively correlated: Citrulline concentration/mean bowel dose during, end of treatment, and four months post-RT; dose-volume parameters/citrulline change groups; cumulative mean radiation dose/intestinal toxicity at end and four months post-RT; citrulline changes/intestinal toxicity during and end of RT. Citrulline concentration changes significantly differed during treatment according to RTOG intestinal toxicity grades (p < 0.0001). Although the citrulline changes differed significantly within RTOG intestinal toxicity grades (p = 0.003), the difference between Grade 0 and Grade 1 did not differ significantly at the end of the treatment. At four months after RT, no significant differences were apparent. Conclusion. Citrulline-based assessment scores are objective and should be considered in measuring radiation-induced intestinal toxicity

Plasma citrulline levels predict intestinal toxicity in patients treated with pelvic radiotherapy

International Nuclear Information System (INIS)

Onal, Cem; Kotek, Ayse; Arslan, Gungor; Topkan, Erkan; Unal, Birsel; Yavuz, Aydin; Yavuz, Melek

2011-01-01

Background. Radiotherapy (RT) for abdominal and pelvic malignancies often causes severe small bowel toxicity. Citrulline concentrations are known to decrease with intestinal failure. We thus evaluated the feasibility of plasma citrulline levels in predicting radiation-induced intestinal toxicity. Material and methods. Fifty-three patients (36 prostate cancer, 17 endometrial cancer) who received 45 Gy pelvic RT using conventional fractionation were prospectively evaluated. Patients with prostate cancer received an additional 25-30.6 Gy conformal boost. Plasma citrulline levels were assessed on day 0, mid- (week 3) and post-RT (week 8), and four months post-RT. Dose-volume histogram, citrulline concentration changes, and weekly intestinal toxicity scores were analyzed. Results. Mean age was 63 years (range: 43-81 years) and mean baseline citrulline concentration was 38.0 ± 10.1 μmol/l. Citrulline concentrations were significantly reduced at week 3 (27.4 ± 5.9 μmol/l; p < 0.0001), treatment end (29.9 ± 8.8 μmol/l; p < 0.0001), and four months post-treatment (34.3 ± 12.1; p 0.01). The following factor pairs were significantly positively correlated: Citrulline concentration/mean bowel dose during, end of treatment, and four months post-RT; dose-volume parameters/citrulline change groups; cumulative mean radiation dose/intestinal toxicity at end and four months post-RT; citrulline changes/intestinal toxicity during and end of RT. Citrulline concentration changes significantly differed during treatment according to RTOG intestinal toxicity grades (p < 0.0001). Although the citrulline changes differed significantly within RTOG intestinal toxicity grades (p = 0.003), the difference between Grade 0 and Grade 1 did not differ significantly at the end of the treatment. At four months after RT, no significant differences were apparent. Conclusion. Citrulline-based assessment scores are objective and should be considered in measuring radiation-induced intestinal toxicity

determination of toxicity levels of some savannah plants using brine

African Journals Online (AJOL)

DR. AMINU

DETERMINATION OF TOXICITY LEVELS OF SOME SAVANNAH PLANTS. USING BRINE ... Adoum, O. A.. Department of Pure and Industrial Chemistry, Bayero University, P.M.B. 3011, Kano – Nigeria. ... 1000, 100, and 10 µg/ml, respectively.

Assessment of sediment metal contamination in the Mar Menor coastal lagoon (SE Spain: Metal distribution, toxicity, bioaccumulation and benthic community structure

Directory of Open Access Journals (Sweden)

2005-01-01

Full Text Available The Mar Menor coastal lagoon is one of the largest of the Mediterranean Sea. Ancient mining activities in the mountains near its southern basin have resulted in metal contamination in the sediment. The metal bioavailability of these sediments was determined through laboratory toxicity bioassays using three Mediterranean sea urchin species and two amphipod species, and by means of field bioaccumulation measurements involving the seagrass Cymodocea nodosa. The effect of sediment metal contamination on benthic communities was assessed through benthic infaunal analyses, applying classical descriptive parameters and multivariate techniques. The sediments affected by the mining activities presented high levels of toxicity and metals were also accumulated in the seagrass tissues, pointing to metal bioavailability. Although the classical benthic indices were not clear indicators of disturbance, the multivariate techniques applied provided more consistent conclusions.

A cost analysis of microalgal biomass and biodiesel production in open raceways treating municipal wastewater and under optimum light wavelength.

Science.gov (United States)

Kang, Zion; Kim, Byung-Hyuk; Ramanan, Rishiram; Choi, Jong-Eun; Yang, Ji-Won; Oh, Hee-Mock; Kim, Hee-Sik

2015-01-01

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.

Community Engagement in a Graduate-Level Community Literacy Course

Science.gov (United States)

Marshall Bowen, Lauren; Arko, Kirsti; Beatty, Joel; Delaney, Cindy; Dorpenyo, Isidore; Moeller, Laura; Roberts, Elsa; Velat, John

2014-01-01

A case study of a graduate-level community literacy seminar that involved a tutoring project with adult digital literacy learners, this essay illustrates the value of community outreach and service-learning for graduate students in writing studies. Presenting multiple perspectives through critical reflection, student authors describe how their…

Correlation of BTEX levels and toxicity of condensate contaminated groundwater

International Nuclear Information System (INIS)

Headley, J.; Goudey, S.; Birkholz, D.; Hardisty, P.

1995-01-01

The concentration of BTEX was determined for 60 groundwater samples collected from 6 gas plants in Western Canada, using conventional purge-and-trap GC/MS procedures. The gas plants were selected to cover different types of operations with different amine process chemicals employed for the sweetening of the raw sour-gas condensates. Aliquots of the ground water samples were subjected to toxicity screening tests, specifically, (a) bacterial luminescence (microtox); (b) daphnia mortality and (c) fathead minnow mortality. For the toxicity tests, sample handling procedures were developed to minimize the loss of volatile organics during the experiments. To account for possible losses, the levels of BTEX were monitored at the start and upon completion of these tests. The results indicated that the toxicity of the groundwater was in general, well correlated to the concentration of BTEX (primarily xylene). Approximately 5% of the samples, however, were observed to be toxic although the concentration of BTEX were below the method detection limit (1 microg/1). Thiophenic volatile organics were implicated for the latter. Based on the laboratory results, the remediation of BTEX is expected to correlate with the removal of the toxicity of the groundwater. These findings are of direct relevance to present technologies employed for remediation of ground water at the Sourgas plants

Evaluation and modeling of the parameters affecting fluoride toxicity level in aquatic environments by bioassay method

Directory of Open Access Journals (Sweden)

Hamid Reza Shamsollahi

2014-04-01

Full Text Available Background: Fluoride exists in various forms in nature and water resources. , The rising level of fluoride in water resources due to discharge of industrial effluents can cause toxicity in aquatic organisms. To prevent toxicity, it is necessary to determine maximum fluoride toxicity as well as effluent discharge limits. The aim of this study was to determine the maximum fluoride toxicity and the factors affecting fluoride toxicity to provide a model in order to determine the effluent discharge limits. Methods: Daphnia magna bioassay in the absence of confounding factors was used to determine the maximum level of fluoride toxicity. Then, bioassay was repeated in the presence of the confounding factors (hardness, temperature and exposure time to determine their effects. Results: In the absence of intervening factors, fluoride LC50 levels determined after 24, 48 and 72 hours exposure were 4.9, 46.5 and 38.7 mg/l, respectively.. Also, the influence of confounding factors on LC50 values was reported significant by Minitab software. Conclusion: Increasing the water hardness reduced fluoride toxicity, and increasing the water temperature and exposure time increased fluoride toxicity in aquatic environments. Therefore, while determining the wastewater discharge limit in terms of fluoride concentration, it is essential to take the effect of confounding factors on fluoride toxicity into account in order to prevent toxicity in the open water resources.

A Review on the Assessment of Stress conditions for Simultaneous Production of Microalgal Lipids and Carotenoids

Directory of Open Access Journals (Sweden)

Amritpreet kaur Minhas

2016-05-01

Full Text Available Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME, and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions.

A Review on the Assessment of Stress Conditions for Simultaneous Production of Microalgal Lipids and Carotenoids

Science.gov (United States)

Minhas, Amritpreet K.; Hodgson, Peter; Barrow, Colin J.; Adholeya, Alok

2016-01-01

Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids) under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C) such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME), and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions. PMID:27199903

Aggregate formation affects ultrasonic disruption of microalgal cells.

Science.gov (United States)

Wang, Wei; Lee, Duu-Jong; Lai, Juin-Yih

2015-12-01

Ultrasonication is a cell disruption process of low energy efficiency. This study dosed K(+), Ca(2+) and Al(3+) to Chlorella vulgaris cultured in Bold's Basal Medium at 25°C and measured the degree of cell disruption under ultrasonication. Adding these metal ions yielded less negatively charged surfaces of cells, while with the latter two ions large and compact cell aggregates were formed. The degree of cell disruption followed: control=K(+)>Ca(2+)>Al(3+) samples. Surface charges of cells and microbubbles have minimal effects on the microbubble number in the proximity of the microalgal cells. Conversely, cell aggregates with large size and compact interior resist cell disruption under ultrasonication. Staining tests revealed high diffusional resistance of stains over the aggregate interior. Microbubbles may not be effective generated and collapsed inside the compact aggregates, hence leading to low cell disruption efficiencies. Effective coagulation/flocculation in cell harvesting may lead to adverse effect on subsequent cell disruption efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microalgal process-monitoring based on high-selectivity spectroscopy tools: status and future perspectives

DEFF Research Database (Denmark)

Podevin, Michael Paul Ambrose; Fotidis, Ioannis; Angelidaki, Irini

2018-01-01

microalgae production towards process automation through multivariate process control (MVPC) and software sensors trained on “big data”. The paper will also include a comprehensive overview of off-line implementations of vibrational spectroscopy in microalgal research as it pertains to spectral...... contribution of this review is to present current and prospective advances of on-line and in-line process analytical technology (PAT), with high-selectivity – the capability of monitoring several analytes simultaneously – in the interest of improving product quality, productivity, and process automation...... interpretation and process automation to aid and motivate development....

Occupancy in community-level studies

Science.gov (United States)

MacKenzie, Darryl I.; Nichols, James; Royle, Andy; Pollock, Kenneth H.; Bailey, Larissa L.; Hines, James

2018-01-01

Another type of multi-species studies, are those focused on community-level metrics such as species richness. In this chapter we detail how some of the single-species occupancy models described in earlier chapters have been applied, or extended, for use in such studies, while accounting for imperfect detection. We highlight how Bayesian methods using MCMC are particularly useful in such settings to easily calculate relevant community-level summaries based on presence/absence data. These modeling approaches can be used to assess richness at a single point in time, or to investigate changes in the species pool over time.

Improving toxicity assessment of pesticide mixtures: the use of polar passive sampling devices extracts in microalgae toxicity tests

Directory of Open Access Journals (Sweden)

Sandra KIM TIAM

2016-09-01

Full Text Available Complexity of contaminants exposure needs to be taking in account for an appropriate evaluation of risks related to mixtures of pesticides released in the ecosystems. Toxicity assessment of such mixtures can be made through a variety of toxicity tests reflecting different level of biological complexity. This paper reviews the recent developments of passive sampling techniques for polar compounds, especially Polar Organic Chemical Integrative Samplers (POCIS and Chemcatcher® and the principal assessment techniques using microalgae in laboratory experiments. The progresses permitted by the coupled use of such passive samplers and ecotoxicology testing as well as their limitations are presented. Case studies combining passive sampling devices (PSD extracts and toxicity assessment toward microorganisms at different biological scales from single organisms to communities level are presented. These case studies, respectively aimed i at characterizing the toxic potential of waters using dose-response curves, and ii at performing microcosm experiments with increased environmental realism in the toxicant exposure in term of cocktail composition and concentration. Finally perspectives and limitations of such approaches for future applications in the area of environmental risk assessment are discussed.

Lifting the veil: Impact of contaminants on coastal phytoplankton

NARCIS (Netherlands)

Sjollema, S.B.

2014-01-01

Coastal waters are among the most productive ecosystems on the planet. Yet, they also suffer from a high contaminant load, resulting in a ‘grey veil’ of contaminants. Exposure of microalgal communities to these contaminants potentially results in shifts in microalgal community composition. As

Advancing the Science of Community-Level Interventions

Science.gov (United States)

Beehler, Sarah; Deutsch, Charles; Green, Lawrence W.; Hawe, Penelope; McLeroy, Kenneth; Miller, Robin Lin; Rapkin, Bruce D.; Schensul, Jean J.; Schulz, Amy J.; Trimble, Joseph E.

2011-01-01

Community interventions are complex social processes that need to move beyond single interventions and outcomes at individual levels of short-term change. A scientific paradigm is emerging that supports collaborative, multilevel, culturally situated community interventions aimed at creating sustainable community-level impact. This paradigm is rooted in a deep history of ecological and collaborative thinking across public health, psychology, anthropology, and other fields of social science. The new paradigm makes a number of primary assertions that affect conceptualization of health issues, intervention design, and intervention evaluation. To elaborate the paradigm and advance the science of community intervention, we offer suggestions for promoting a scientific agenda, developing collaborations among professionals and communities, and examining the culture of science. PMID:21680923

Effects of crude kerosene on testosterone levels, aggression and toxicity in rat

Directory of Open Access Journals (Sweden)

Rachel W. Njoroge

2015-01-01

Full Text Available The use of crude kerosene as a dietary supplement in boarding schools has been a common practice in east Africa and other countries for many years, with the belief of it reducing the sex drive (libido at the pubertal stage. There is however no scientific basis for this belief. The present study aimed at using a rat animal model to investigate the effects of crude kerosene on serum testosterone levels, aggression and its possible toxic effects. Fifteen male albino rats of approximately similar age and average weights were put into three groups of five animals each; the control group (placebo, low kerosene dose (10 μl/day group and high kerosene dose (300 μl/day group. ELISA was used to determine the serum testosterone levels. During treatment, changes in aggression were observed and noted. Liver toxicity was determined using enzyme assays, total protein and albumin while renal toxicity was monitored using serum creatinine levels. A full hemogram was conducted to determine hematological effects. Various tissue biopsies were obtained and examined using histopathological techniques for evidence of toxicity. Contrary to the common belief, our findings showed an overall increase of serum testosterone levels of up to 66% in the low dose and 75% in the high dose groups, with an increasing trend by the end of the study. The high dose group showed significantly increased levels of white blood cells (WBC (p = 0.036, red blood cells (RBC (p = 0.025, hematocrit (HCT (p = 0.03, red cell distribution width (p = 0.028 and platelets (p = 0.017. The histological results of the stomach indicated chronic gastritis.

75 FR 19319 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension of Comment...

Science.gov (United States)

2010-04-14

... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension of Comment Period... reporting requirements for hydrogen sulfide (Chemical Abstracts Service Number (CAS No.) 7783-06-4) (75 FR... may be potentially affected by this action if you manufacture, process, or otherwise use hydrogen...

Incorporating Ecosystem Services into Community-level ...

Science.gov (United States)

EPA’s Office of Research and Development’s Sustainable and Healthy Communities Research Program is developing tools and approaches to incorporate ecosystem goods and services concepts into community-level decision-making. The San Juan Community Study is one of a series of coordinated community studies, which also include Mobile Bay, AL, Great Lakes Areas of Concern, and the Pacific Northwest. Common elements across the community studies include a focus on watershed management and national estuary programs (National Estuary Program, National Estuarine Research Reserve System). San Juan, Puerto Rico, is unique from the other community studies in that it is located in a highly urbanized watershed integrated with a number of freshwater and coastal ecosystems. The San Juan Community Study will explore linkages between watershed management decisions (e.g., dredging canals, restoration of mangrove buffers, sewage discharge interventions, climate adaptive strategies) targeting priority stressors (e.g., nutrients, contaminants, and pathogens; aquatic debris; habitat loss; modified hydrology and water circulation; sea level rise; storm intensity and frequency) effecting the condition of ecosystems (e.g., estuarine habitats and fish, as well as the connected terrestrial and coastal ecosystems), associated ecosystem goods and services (e.g., tourism and recreation, fishing, nutrient & sediment retention, contaminant processing, carbon sequestration, flood protection),

Production of Microalgal Lipids as Biodiesel Feedstock with Fixation of CO2 by Chlorella vulgaris

OpenAIRE

Qiao Hu; Sen-Xiang Zhang; Zhong-Hua Yang; Hao Huang; Rong Zeng

2014-01-01

The global warming and shortage of energy are two critical problems for human social development. CO2 mitigation and replacing conventional diesel with biodiesel are effective routes to reduce these problems. Production of microalgal lipids as biodiesel feedstock by a freshwater microalga, Chlorella vulgaris, with the ability to fixate CO2 is studied in this work. The results show that nitrogen deficiency, CO2 volume fraction and photoperiod are the key factors responsible for the lipid accum...

Lipid Production of Heterotrophic Chlorella sp. from Hydrolysate Mixtures of Lipid-Extracted Microalgal Biomass Residues and Molasses.

Science.gov (United States)

Zheng, Hongli; Ma, Xiaochen; Gao, Zhen; Wan, Yiqin; Min, Min; Zhou, Wenguang; Li, Yun; Liu, Yuhuan; Huang, He; Chen, Paul; Ruan, Roger

2015-10-01

This study investigated the feasibility of lipid production of Chlorella sp. from waste materials. Lipid-extracted microalgal biomass residues (LMBRs) and molasses were hydrolyzed, and their hydrolysates were analyzed. Five different hydrolysate mixture ratios (w/w) of LMBRs/molasses (1/0, 1/1, 1/4, 1/9, and 0/1) were used to cultivate Chlorella sp. The results showed that carbohydrate and protein were the two main compounds in the LMBRs, and carbohydrate was the main compound in the molasses. The highest biomass concentration of 5.58 g/L, Y biomass/sugars of 0.59 g/g, lipid productivity of 335 mg/L/day, and Y lipids/sugars of 0.25 g/g were obtained at the hydrolysate mixture ratio of LMBRs/molasses of 1/4. High C/N ratio promoted the conversion of sugars into lipids. The lipids extracted from Chlorella sp. shared similar lipid profile of soybean oil and is therefore a potential viable biodiesel feedstock. These results showed that Chlorella sp. can utilize mixed sugars and amino acids from LMBRs and molasses to accumulate lipids efficiently, thus reducing the cost of microalgal biodiesel production and improving its economic viability.

2008 Toxic Chemical Release Inventory 2008 Toxic Chemical Release Inventory Community Right-to-Know Act of 1986, Title III, Section 313

Energy Technology Data Exchange (ETDEWEB)

Ecology and Air Quality Group

2009-10-01

For reporting year 2008, Los Alamos National Laboratory (LANL) submitted a Form R report for lead as required under the Emergency Planning and Community Right-to- Know Act (EPCRA) Section 313. No other EPCRA Section 313 chemicals were used in 2008 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2008, as well as to provide background information about data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxic Chemical Release Inventory Report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999, EPA promulgated a final rule on persistent bioaccumulative toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R.

Molecular toxicity of nanomaterials.

Science.gov (United States)

Chang, Xue-Ling; Yang, Sheng-Tao; Xing, Gengmei

2014-10-01

With the rapid developments in the fields of nanoscience and nanotechnlogy, more and more nanomaterials and their based consumer products have been used into our daily life. The safety concerns of nanomaterials have been well recognized by the scientific community and the public. Molecular mechanism of interactions between nanomaterials and biosystems is the most essential topic and final core of the biosafety. In the last two decades, nanotoxicology developed very fast and toxicity phenomena of nanomaterials have been reported. To achieve better understanding and detoxication of nanomaterials, thorough studies of nanotoxicity at molecular level are important. The interactions between nanomaterials and biomolecules have been widely investigated as the first step toward the molecular nanotoxicology. The consequences of such interactions have been discussed in the literature. Besides this, the chemical mechanism of nanotoxicology is gaining more attention, which would lead to a better design of nontoxic nanomaterials. In this review, we focus on the molecular nanotoxicology and explore the toxicity of nanomaterials at molecular level. The molecular level studies of nanotoxicology are summarized and the published nanotoxicological data are revisited.

Characterization of the bacterial metagenome in an industrial algae bioenergy production system

Energy Technology Data Exchange (ETDEWEB)

Huang, Shi [Chinese Academy of Sciences; Fulbright, Scott P [Colorado State University; Zeng, Xiaowei [Chinese Academy of Sciences; Yates, Tracy [Solix Biofuels; Wardle, Greg [Solix Biofuels; Chisholm, Stephen T [Colorado State University; Xu, Jian [Chinese Academy of Sciences; Lammers, Peter [New Mexico State University

2011-03-16

Cultivation of oleaginous microalgae for fuel generally requires growth of the intended species to the maximum extent supported by available light. The presence of undesired competitors, pathogens and grazers in cultivation systems will create competition for nitrate, phosphate, sulfate, iron and other micronutrients in the growth medium and potentially decrease microalgal triglyceride production by limiting microalgal health or cell density. Pathogenic bacteria may also directly impact the metabolism or survival of individual microalgal cells. Conversely, symbiotic bacteria that enhance microalgal growth may also be present in the system. Finally, the use of agricultural and municipal wastes as nutrient inputs for microalgal production systems may lead to the introduction and proliferation of human pathogens or interfere with the growth of bacteria with beneficial effects on system performance. These considerations underscore the need to understand bacterial community dynamics in microalgal production systems in order to assess microbiome effects on microalgal productivity and pathogen risks. Here we focus on the bacterial component of microalgal production systems and describe a pipeline for metagenomic characterization of bacterial diversity in industrial cultures of an oleaginous alga, Nannochloropsis salina. Environmental DNA was isolated from 12 marine algal cultures grown at Solix Biofuels, a region of the 16S rRNA gene was amplified by PCR, and 16S amplicons were sequenced using a 454 automated pyrosequencer. The approximately 70,000 sequences that passed quality control clustered into 53,950 unique sequences. The majority of sequences belonged to thirteen phyla. At the genus level, sequences from all samples represented 169 different genera. About 52.94% of all sequences could not be identified at the genus level and were classified at the next highest possible resolution level. Of all sequences, 79.92% corresponded to 169 genera and 70 other taxa. We

Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production.

Science.gov (United States)

Mandal, Shovon; Patnaik, Reeza; Singh, Amit Kumar; Mallick, Nirupama

2013-01-01

Biodiesel, using microalgae as feedstocks, is being explored as the most potent form of alternative diesel fuel for sustainable economic development. A comparative assessment of various protocols for microalgal lipid extraction was carried out using five green algae, six blue-green algae and two diatom species treated with different single and binary solvents both at room temperature and using a soxhlet. Lipid recovery was maximum with chloroform-methanol in the soxhlet extractor. Pretreatments ofbiomass, such as sonication, homogenization, bead-beating, lyophilization, autoclaving, microwave treatment and osmotic shock did not register any significant rise in lipid recovery. As lipid recovery using chloroform-methanol at room temperature demonstrated a marginally lower value than that obtained under the soxhlet extractor, on economical point of view, the former is recommended for microalgal total lipid extraction. Transesterification process enhances the quality of biodiesel. Experiments were designed to determine the effects of catalyst type and quantity, methanol to oil ratio, reaction temperature and time on the transesterification process using response surface methodology. Fatty acid methyl ester yield reached up to 91% with methanol:HCl:oil molar ratio of 82:4:1 at 65 degrees C for 6.4h reaction time. The biodiesel yield relative to the weight of the oil was found to be 69%.

Risk Levels of Toxic Cyanobacteria in Portuguese Recreational Freshwaters

Directory of Open Access Journals (Sweden)

Carina Menezes

2017-10-01

Full Text Available Portuguese freshwater reservoirs are important socio-economic resources, namely for recreational use. National legislation concerning bathing waters does not include mandatory levels or guidelines for cyanobacteria and cyanotoxins. This is an issue of concern since cyanotoxin-based evidence is insufficient to change the law, and the collection of scientific evidence has been hampered by the lack of regulatory levels for cyanotoxins in bathing waters. In this work, we evaluate the profile of cyanobacteria and microcystins (MC in eight freshwater reservoirs from the center of Portugal, used for bathing/recreation, in order to determine the risk levels concerning toxic cyanobacteria occurrence. Three of the reservoirs did not pose a risk of MC contamination. However, two reservoirs presented a high risk in 7% of the samples according to the World Health Organization (WHO guidelines for MC in bathing waters (above 20 µg/L. In the remaining three reservoirs, the risk concerning microcystins occurrence was low. However, they exhibited recurrent blooms and persistent contamination with MC up to 4 µg/L. Thus, the risk of exposure to MC and potential acute and/or chronic health outcomes should not be disregarded in these reservoirs. These results contribute to characterize the cyanobacterial blooms profile and to map the risk of toxic cyanobacteria and microcystins occurrence in Portuguese inland waters.

Characterization of a microalgal mutant for CO_2 biofixation and biofuel production

International Nuclear Information System (INIS)

Qi, Feng; Pei, Haiyan; Hu, Wenrong; Mu, Ruimin; Zhang, Shuo

2016-01-01

Highlights: • Combination of the isolation using 96-well microplates and traditional UV mutagenesis for screening HCT mutant. • Microalgal mutant Chlorella vulgaris SDEC-3M was screened out by modified UV mutagenesis. • SDEC-3M showed high CO_2 tolerance, high CO_2 requiring and relevant genetic stability. • LCE and carbohydrate content of SDEC-3M were significantly elevated. • SDEC-3M offers a strong candidature as CO_2 biofixation and biofuel production. - Abstract: In the present work, a Chlorella vulgaris mutant, named as SDEC-3M, was screened out through the combination of the isolation using 96-well microplates and traditional UV mutagenesis. Compared with its parent (wild type), the growth of SDEC-3M preferred higher CO_2 (15% v/v) environment to ambient air (0.038% CO_2 (v/v)), indicating that the mutant qualified with good tolerance and growth potential under high level CO_2 (high CO_2 tolerance) but was defective in directly utilizing the low level CO_2 (high CO_2 requiring). The genetic stability under ambient air and high level CO_2 was confirmed by a continuous cultivation for five generations. Higher light conversion efficiency (14.52%) and richer total carbohydrate content (42.48%) demonstrated that both solar energy and CO_2 were more effectively productively fixed into carbohydrates for bioethanol production than the parent strain. The mutant would benefit CO_2 biofixation from industrial exhaust gas to mitigate of global warming and promote biofuel production to relieve energy shortage.

Production of Microalgal Lipids as Biodiesel Feedstock with Fixation of CO2 by Chlorella vulgaris

Directory of Open Access Journals (Sweden)

Qiao Hu

2014-01-01

Full Text Available The global warming and shortage of energy are two critical problems for human social development. CO2 mitigation and replacing conventional diesel with biodiesel are effective routes to reduce these problems. Production of microalgal lipids as biodiesel feedstock by a freshwater microalga, Chlorella vulgaris, with the ability to fixate CO2 is studied in this work. The results show that nitrogen deficiency, CO2 volume fraction and photoperiod are the key factors responsible for the lipid accumulation in C. vulgaris. With 5 % CO2, 0.75 g/L of NaNO3 and 18:6 h of light/dark cycle, the lipid content and overall lipid productivity reached 14.5 % and 33.2 mg/(L·day, respectively. Furthermore, we proposed a technique to enhance the microalgal lipid productivity by activating acetyl-CoA carboxylase (ACCase with an enzyme activator. Citric acid and Mg2+ were found to be efficient enzyme activators of ACCase. With the addition of 150 mg/L of citric acid or 1.5 mmol/L of MgCl2, the lipid productivity reached 39.1 and 38.0 mg/(L·day, respectively, which was almost twofold of the control. This work shows that it is practicable to produce lipids by freshwater microalgae that can fixate CO2, and provides a potential route to solving the global warming and energy shortage problems.

Individual, population and community level effects of subtle anthropogenic contamination in estuarine meiobenthos

International Nuclear Information System (INIS)

Rubal, Marcos; Guilhermino, Lucia M.; Medina, Matias H.

2009-01-01

The study presented here searched for the level of taxonomic resolution required to detect the effects of low-level chronic pollution on estuarine meiobenthic communities. Meiofauna from two sites, with special attention to harpacticoid copepods, was analysed at different taxonomic levels of aggregation using uni- and multivariate methods. Adaptation processes that could buffer biodiversity disruptions were also considered through the analysis of fitness-related and tolerance traits in the harpacticoid copepod Paronychocamptus nanus. Results showed that uni- and multivariate analyses could be inadequate when assessing subtle anthropogenic contamination. Instead, the assessment of inter-population differences in tolerance to the main source of stress rises as a required procedure if potential effects of this type of contamination are being investigated. Specifically, a 96 h acute toxicity test performed with populations from the affected site appears as a faster and reliable general tool to assess impacts of low-level chronic pollution in estuaries. - Tolerance of local populations as a reliable tool to assess impacts of subtle anthropogenic contamination in estuaries.

Individual, population and community level effects of subtle anthropogenic contamination in estuarine meiobenthos

Energy Technology Data Exchange (ETDEWEB)

Rubal, Marcos [CIIMAR/CIMAR-LA - Centro Interdisciplinar de Investigacao Marinha e Ambiental, Universidade do Porto, Laboratorio de Ecotoxicologia, Rua dos Bragas 289, 4050-123 Porto (Portugal); Guilhermino, Lucia M. [CIIMAR/CIMAR-LA - Centro Interdisciplinar de Investigacao Marinha e Ambiental, Universidade do Porto, Laboratorio de Ecotoxicologia, Rua dos Bragas 289, 4050-123 Porto (Portugal); ICBAS - Instituto de Ciencias Biomedicas de Abel Salazar, Departamento de Estudos de Populacoes, Laboratorio de Ecotoxicologia, Universidade do Porto, Lg. Prof. Abel Salazar 2, 4099-003 Porto (Portugal); Medina, Matias H., E-mail: matias.medina@avs-chile.c [AVS Chile SA, Imperial 0655, Off. 3A, Puerto Varas (Chile); Centro i-mar, Universidad de Los Lagos, Camino Chinquihue km 6, Puerto Montt (Chile)

2009-10-15

The study presented here searched for the level of taxonomic resolution required to detect the effects of low-level chronic pollution on estuarine meiobenthic communities. Meiofauna from two sites, with special attention to harpacticoid copepods, was analysed at different taxonomic levels of aggregation using uni- and multivariate methods. Adaptation processes that could buffer biodiversity disruptions were also considered through the analysis of fitness-related and tolerance traits in the harpacticoid copepod Paronychocamptus nanus. Results showed that uni- and multivariate analyses could be inadequate when assessing subtle anthropogenic contamination. Instead, the assessment of inter-population differences in tolerance to the main source of stress rises as a required procedure if potential effects of this type of contamination are being investigated. Specifically, a 96 h acute toxicity test performed with populations from the affected site appears as a faster and reliable general tool to assess impacts of low-level chronic pollution in estuaries. - Tolerance of local populations as a reliable tool to assess impacts of subtle anthropogenic contamination in estuaries.

Evaluation and modeling of the parameters affecting fluoride toxicity level in aquatic environments by bioassay method

OpenAIRE

Hamid Reza Shamsollahi; Hadi asady; Amir Hossein Mahvi; Zahra zolghadr

2014-01-01

Background: Fluoride exists in various forms in nature and water resources. , The rising level of fluoride in water resources due to discharge of industrial effluents can cause toxicity in aquatic organisms. To prevent toxicity, it is necessary to determine maximum fluoride toxicity as well as effluent discharge limits. The aim of this study was to determine the maximum fluoride toxicity and the factors affecting fluoride toxicity to provide a model in order to determine the effluent discha...

Biodiesel production by direct transesterification of microalgal biomass with co-solvent.

Science.gov (United States)

Zhang, Yan; Li, Ya; Zhang, Xu; Tan, Tianwei

2015-11-01

In this study, a direct transesterification process using 75% ethanol and co-solvent was studied to reduce the energy consumption of lipid extraction process and improve the conversion yield of the microalgae biodiesel. The addition of a certain amount of co-solvent (n-hexane is most preferable) was required for the direct transesterification of microalgae biomass. With the optimal reaction condition of n-hexane to 75% ethanol volume ratio 1:2, mixed solvent dosage 6.0mL, reaction temperature 90°C, reaction time 2.0h and catalyst volume 0.6mL, the direct transesterification process of microalgal biomass resulted in a high conversion yield up to 90.02±0.55wt.%. Copyright © 2015 Elsevier Ltd. All rights reserved.

1992 Toxic Chemical Release Inventory: Emergency Planning and Community Right-To-Know-Act of 1986 Section 313

International Nuclear Information System (INIS)

1993-07-01

Section 313 of the Emergency Planning and Community Right-To-Know Act of 1986 (EPCRA) requires the annual submittal of toxic chemical release information to the US Environmental Protection Agency (EPA). The following document is the July 1993 submittal of the EPCRA Toxic Chemical Release Inventory Report (Form R). Included is a Form R for chlorine and for lead, the two chemicals used in excess of the established regulatory thresholds at the Hanford Site by the US Department of Energy, Richland Operations Office and its contractors during calendar year 1992

Using Population Dose to Evaluate Community-level Health Initiatives.

Science.gov (United States)

Harner, Lisa T; Kuo, Elena S; Cheadle, Allen; Rauzon, Suzanne; Schwartz, Pamela M; Parnell, Barbara; Kelly, Cheryl; Solomon, Loel

2018-05-01

Successful community-level health initiatives require implementing an effective portfolio of strategies and understanding their impact on population health. These factors are complicated by the heterogeneity of overlapping multicomponent strategies and availability of population-level data that align with the initiatives. To address these complexities, the population dose methodology was developed for planning and evaluating multicomponent community initiatives. Building on the population dose methodology previously developed, this paper operationalizes dose estimates of one initiative targeting youth physical activity as part of the Kaiser Permanente Community Health Initiative, a multicomponent community-level obesity prevention initiative. The technical details needed to operationalize the population dose method are explained, and the use of population dose as an interim proxy for population-level survey data is introduced. The alignment of the estimated impact from strategy-level data analysis using the dose methodology and the data from the population-level survey suggest that dose is useful for conducting real-time evaluation of multiple heterogeneous strategies, and as a viable proxy for existing population-level surveys when robust strategy-level evaluation data are collected. This article is part of a supplement entitled Building Thriving Communities Through Comprehensive Community Health Initiatives, which is sponsored by Kaiser Permanente, Community Health. Copyright © 2018 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Sensing of phosphates by using luminescent Eu(III) and Tb(III) complexes: application to the microalgal cell Chlorella vulgaris.

Science.gov (United States)

Nadella, Sandeep; Sahoo, Jashobanta; Subramanian, Palani S; Sahu, Abhishek; Mishra, Sandhya; Albrecht, Markus

2014-05-12

Phenanthroline-based chiral ligands L(1) and L(2) as well as the corresponding Eu(III) and Tb(III) complexes were synthesized and characterized. The coordination compounds show red and green emission, which was explored for the sensing of a series of anions such as F(-), Cl(-), Br(-), I(-), NO3(-), NO2(-), HPO4(2-), HSO4(-), CH3COO(-), and HCO3(-). Among the anions, HPO4(2-) exhibited a strong response in the emission property of both europium(III) and terbium(III) complexes. The complexes showed interactions with the nucleoside phosphates adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). Owing to this recognition, these complexes have been applied as staining agents in the microalgal cell Chlorella vulgaris. The stained microalgal cells were monitored through fluorescence microscopy and scanning electron microscopy. Initially, the complexes bind to the outer cell wall and then enter the cell wall through holes in which they probably bind to phospholipids. This leads to a quenching of the luminescence properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Toxicity of leather tanning wastewater effluents in sea urchin early development and in marine microalgae.

Science.gov (United States)

Meriç, Süreyya; De Nicola, Elena; Iaccarino, Mario; Gallo, Marialuisa; Di Gennaro, Annamaria; Morrone, Gaetano; Warnau, Michel; Belgiorno, Vincenzo; Pagano, Giovanni

2005-10-01

This study was designed to investigate the composition and the toxicity of leather tanning wastewater and conditioned sludge collected at the leather tanning wastewater treatment plant (CODISO) located in Solofra, Avellino (Southern Italy). Samples were analyzed for their conventional parameters (COD, TSS, chromium and ammonia) and for metal content. Effluent samples included raw wastewater, and samples collected following coagulation/flocculation process and biological treatment. A set of toxicity endpoints were tested using sea urchin and marine microalgal bioassays by evaluating acute embryotoxicity, developmental defects, changes in sperm fertilization success and transmissible damage from sperm to the offspring, and changes in algal growth rate. Dose-related toxicity to sea urchin embryogenesis and sperm fertilization success was exerted by effluent or sludge samples according to the following rank: conditioned sludge > coagulated effluent > or = raw influent > effluent from biological treatment. Offspring quality was not affected by sperm exposure to any wastewater or to sludge samples. Algal growth was inhibited by raw or coagulated effluent to a similar extent and, again, the effluent from the biological treatment resulted in a decreased toxicity. The results suggest that coagulated effluent and conditioned sludge result in higher toxicity than raw influent in sea urchin embryos and sperm, whereas the biological wastewater treatment of coagulated effluent, in both sea urchins and algae, cause a substantial improvement of wastewater quality. Hence a final biological wastewater treatment should be operated to minimize any environmental damage from tannery wastewater.

Identification of overlapping communities and their hierarchy by locally calculating community-changing resolution levels

OpenAIRE

Havemann, Frank; Heinz, Michael; Struck, Alexander; Gläser, Jochen

2010-01-01

We propose a new local, deterministic and parameter-free algorithm that detects fuzzy and crisp overlapping communities in a weighted network and simultaneously reveals their hierarchy. Using a local fitness function, the algorithm greedily expands natural communities of seeds until the whole graph is covered. The hierarchy of communities is obtained analytically by calculating resolution levels at which communities grow rather than numerically by testing different resolution levels. This ana...

Assessment of the toxicity level of an industrial eco-system for its hazardous metals

International Nuclear Information System (INIS)

Husaini, S.N.; Matiullah; Arif, M.

2011-01-01

Pakistan is an agricultural country, yet it is facing a serious threat due to the shortage of water resources and degradation of the agricultural land by the pollution of industrial effluents. A limited number of the current industries are equipped with proper operating treatment plants. Generally, the untreated effluents are disposed off to the open environment which is used for irrigation purposes. Therefore, vegetables and crops grown around the industrial areas is a major potential source of metal poisoning which pose a serious risk to the general public. Hence, study of the toxicity level in vegetables and crops is highly desirable. In this regard, systematic studies have been carried out to determine concentration levels of toxic elements in the samples of vegetables, crops, effluents and soil collected from the industrial areas of the Faisalabad. After processing, these samples were analyzed using neutron activation analysis and atomic absorption spectrometric techniques. The highest concentrations of toxic metals were observed for As (2.73 ± 0.34) in cabbage, Cd (1.5 ± 0.1), Ni (5.1 ± 0.9) and Pb (4.3 ± 0.2) in corn, Co (0.65 ± 0.02), and Sb (0.09 ± 0.01) in carrot, Cr (9.63 ± 1.3), Mn (46.5 ± 4.2) and Se (1.03 ± 0.1) in millet, Cu (11.3 ± 1.1) in tomato vegetables and crop samples. Although, the observed toxicity levels in vegetables and crop samples were higher than those grown in non-industrial areas, yet these toxicity levels are within the safe recommended limits. (author)

Harvesting Environmental Microalgal Blooms for Remediation and Resource Recovery: A Laboratory Scale Investigation with Economic and Microbial Community Impact Assessment

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Jagroop Pandhal

2017-12-01

Full Text Available A laboratory based microflotation rig termed efficient FLOtation of Algae Technology (eFLOAT was used to optimise parameters for harvesting microalgal biomass from eutrophic water systems. This was performed for the dual objectives of remediation (nutrient removal and resource recovery. Preliminary experiments demonstrated that chitosan was more efficient than alum for flocculation of biomass and the presence of bacteria could play a positive role and reduce flocculant application rates under the natural conditions tested. Maximum biomass removal from a hyper-eutrophic water retention pond sample was achieved with 5 mg·L−1 chitosan (90% Chlorophyll a removal. Harvesting at maximum rates showed that after 10 days, the bacterial diversity is significantly increased with reduced cyanobacteria, indicating improved ecosystem functioning. The resource potential within the biomass was characterized by 9.02 μg phosphate, 0.36 mg protein, and 103.7 μg lipid per mg of biomass. Fatty acid methyl ester composition was comparable to pure cultures of microalgae, dominated by C16 and C18 chain lengths with saturated, monounsaturated, and polyunsaturated fatty acids. Finally, the laboratory data was translated into a full-size and modular eFLOAT system, with estimated costs as a novel eco-technology for efficient algal bloom harvesting.

Combining polar organic chemical integrative samplers (POCIS) with toxicity testing to evaluate pesticide mixture effects on natural phototrophic biofilms

International Nuclear Information System (INIS)

Pesce, Stephane; Morin, Soizic; Lissalde, Sophie; Montuelle, Bernard; Mazzella, Nicolas

2011-01-01

Polar organic chemical integrative samplers (POCIS) are valuable tools in passive sampling methods for monitoring polar organic pesticides in freshwaters. Pesticides extracted from the environment using such methods can be used to toxicity tests. This study evaluated the acute effects of POCIS extracts on natural phototrophic biofilm communities. Our results demonstrate an effect of POCIS pesticide mixtures on chlorophyll a fluorescence, photosynthetic efficiency and community structure. Nevertheless, the range of biofilm responses differs according to origin of the biofilms tested, revealing spatial variations in the sensitivity of natural communities in the studied stream. Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment. - Research highlights: → Polar organic chemical integrative samplers (POCIS) were used for monitoring polar organic pesticides in a contaminated river. → The acute effects of POCIS extracts were tested on natural phototrophic biofilm communities. → POCIS pesticide mixtures affected chlorophyll a fluorescence, photosynthetic efficiency and community structure. → Biofilm responses differed according to origin of the biofilms tested, revealing variations in the sensitivity of natural communities. → Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment. - Pesticide mixtures extracted from POCIS can affect chl a fluorescence, photosynthetic efficiency and community structure of natural biofilms.

The Severity of Autism Is Associated with Toxic Metal Body Burden and Red Blood Cell Glutathione Levels

Energy Technology Data Exchange (ETDEWEB)

Adams, J B; Mitchell, I J [Division of Basic Medical Sciences, Southwest College of Naturopathic Medicine, Tempe, AZ 85282 (United States); Baral, M; Bradstreet, J [Department of Pediatric Medicine, Southwest College of Naturopathic Medicine, Tempe, AZ 85282 (United States); Geis, E; Ingram, J; Hensley, A; Zappia, I; Gehn, E; Mitchell, K [Autism Research Institute, San Diego, CA 92116-2599 (United States); Newmark, S [Center for Integrative Pediatric Medicine, Tucson, AZ 85711 (United States); Rubin, R A [Department of Mathematics, Whittier College, Whittier, CA 90601-4413 (United States); Bradstreet, J [International Child Development Resource Center, Phoenix, AZ (United States); El-Dahrn, J M [Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112 (United States)

2009-07-01

This study investigated the relationship of children's autism symptoms with their toxic metal body burden and red blood cell (RBC) glutathione levels. In children ages 38 years, the severity of autism was assessed using four tools: ADOS, PDD-BI, ATEC, and SAS. Toxic metal body burden was assessed by measuring urinary excretion of toxic metals, both before and after oral dimercaptosuccinic acid (DMSA). Multiple positive correlations were found between the severity of autism and the urinary excretion of toxic metals. Variations in the severity of autism measurements could be explained, in part, by regression analyses of urinary excretion of toxic metals before and after DMSA and the level of RBC glutathione (adjusted R2 of 0.220.45, P<.005 in all cases). This study demonstrates a significant positive association between the severity of autism and the relative body burden of toxic metals.

The Severity of Autism Is Associated with Toxic Metal Body Burden and Red Blood Cell Glutathione Levels

International Nuclear Information System (INIS)

Adams, J.B.; Mitchell, I.J.; Baral, M.; Bradstreet, J.; Geis, E.; Ingram, J.; Hensley, A.; Zappia, I.; Gehn, E.; Mitchell, K.; Newmark, S.; Rubin, R.A.; Bradstreet, J.; El-Dahrn, J.M.

2009-01-01

This study investigated the relationship of children's autism symptoms with their toxic metal body burden and red blood cell (RBC) glutathione levels. In children ages 38 years, the severity of autism was assessed using four tools: ADOS, PDD-BI, ATEC, and SAS. Toxic metal body burden was assessed by measuring urinary excretion of toxic metals, both before and after oral dimercaptosuccinic acid (DMSA). Multiple positive correlations were found between the severity of autism and the urinary excretion of toxic metals. Variations in the severity of autism measurements could be explained, in part, by regression analyses of urinary excretion of toxic metals before and after DMSA and the level of RBC glutathione (adjusted R2 of 0.220.45, P<.005 in all cases). This study demonstrates a significant positive association between the severity of autism and the relative body burden of toxic metals.

Looking Ahead Toward Community-Level Strategies to Prevent Sexual Violence

Science.gov (United States)

DeGue, Sarah; Holt, Melissa K.; Massetti, Greta M.; Matjasko, Jennifer L.; Tharp, Andra Teten; Valle, Linda Anne

2018-01-01

The Division of Violence Prevention within CDC’s National Center for Injury Prevention and Control recently undertook a systematic review of primary prevention strategies for sexual violence (SV) perpetration. This review identified the lack of community-level strategies to prevent SV as a critical gap in the literature. Community-level strategies function by modifying the characteristics of settings (e.g., schools, workplaces, neighborhoods) that increase the risk for violence victimization and perpetration. Identification of evidence-based strategies at the community level would allow implementation of ecologic approaches to SV prevention with a greater potential for reducing the prevalence of SV perpetration. The field will face several challenges in identifying and evaluating the effectiveness of promising community-level strategies to prevent SV. These challenges include limited knowledge of community-level and societal-level risk factors for SV, a lack of theoretical or empirical guidance in the SV literature for identification of promising community-level approaches, and challenges in evaluating SV outcomes at the community level. Recognition of these challenges should guide future research and foster dialogue within the SV prevention field. The development and evaluation of community-level approaches to SV prevention represent a vital and logical next step toward the implementation of effective, multilevel prevention efforts and a population-level reduction in the prevalence of SV. PMID:22185587

Molasses wastewater treatment and lipid production at low temperature conditions by a microalgal mutant Scenedesmus sp. Z-4

OpenAIRE

Ma, Chao; Wen, Hanquan; Xing, Defeng; Pei, Xuanyuan; Zhu, Jiani; Ren, Nanqi; Liu, Bingfeng

2017-01-01

Background Simultaneous wastewater treatment and lipid production by oleaginous microalgae show great potential to alleviate energy shortage and environmental pollution, because they exhibit tremendous advantages over traditional activated sludge. Currently, most research on wastewater treatment by microalgal are carried out at optimized temperature conditions (25?35??C), but no information about simultaneous wastewater treatment and lipid production by microalgae at low temperatures has been...

Harvesting microalgae using activated sludge can decrease polymer dosing and enhance methane production via co-digestion in a bacterial-microalgal process

DEFF Research Database (Denmark)

Wágner, Dorottya Sarolta; Radovici, Maria; Smets, Barth F.

2016-01-01

, there is the potential to produce energy by co-digesting the two types of biomass. We present an innovative approach to recover microalgal biomass via a two-step flocculation using bacterial biomass after the destabilisation of microalgae with conventional cationic polymer. A short solids retention time (SRT) enhanced...

Manganese toxicity in pasture legumes. II. Effects of pH and molybdenum levels in the substrate

Energy Technology Data Exchange (ETDEWEB)

Truong, N V; Andrew, C S; Wilson, G L

1971-06-01

The effects of pH and Mo levels in the growing media on Mn toxicity were investigated for white clover and five tropical pasture legume species. In solution culture, high Mo supply did not influence Mn toxicity. However, in two species, it caused Mo toxicity. High solution pH intensified Mn toxicity in white clover, probably by way of uptake. The effects of Ca and P on Mn toxicity reported in a previous paper, were not greatly influenced by solution pH. In the soil, Mo application greatly increased dry matter yield of white clover grown on soils high in exchangeable Mn. This effect was more easily attributed to an influence on N metabolism of the legume plant than on Mn toxicity. Measured soil pH was found to have little influence on the level of exchangeable Mn in the soil. However the larger pH changes in small soil pockets, resulting from non-uniform incorporation of chemicals in the soil, might have a more important effect on this fraction of soil Mn. 31 references, 7 tables.

Microalgal Species Selection for Biodiesel Production Based on Fuel Properties Derived from Fatty Acid Profiles

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Md. Nurun Nabi

2013-10-01

Full Text Available Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE and Graphical Analysis for Interactive Assistance (GAIA analysis. Fatty acid methyl ester (FAME profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN, iodine value (IV, cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA contents. Application of a polyunsaturated fatty acid (PUFA weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis.

Biological Soil Crusts of Arctic Svalbard—Water Availability as Potential Controlling Factor for Microalgal Biodiversity

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Nadine Borchhardt

2017-08-01

Full Text Available In the present study the biodiversity of biological soil crusts (BSCs formed by phototrophic organisms were investigated on Arctic Svalbard (Norway. These communities exert several important ecological functions and constitute a significant part of vegetation at high latitudes. Non-diatom eukaryotic microalgal species of BSCs from 20 sampling stations around Ny-Ålesund and Longyearbyen were identified by morphology using light microscopy, and the results revealed a high species richness with 102 species in total. 67 taxa belonged to Chlorophyta (31 Chlorophyceae and 36 Trebouxiophyceae, 13 species were Streptophyta (11 Klebsormidiophyceae and two Zygnematophyceae and 22 species were Ochrophyta (two Eustigmatophyceae and 20 Xanthophyceae. Surprisingly, Klebsormidium strains belonging to clade G (Streptophyta, which were so far described from Southern Africa, could be determined at 5 sampling stations. Furthermore, comparative analyses of Arctic and Antarctic BSCs were undertaken to outline differences in species composition. In addition, a pedological analysis of BSC samples included C, N, S, TP (total phosphorus, and pH measurements to investigate the influence of soil properties on species composition. No significant correlation with these chemical soil parameters was confirmed but the results indicated that pH might affect the BSCs. In addition, a statistically significant influence of precipitation on species composition was determined. Consequently, water availability was identified as one key driver for BSC biodiversity in Arctic regions.

Biological Soil Crusts of Arctic Svalbard-Water Availability as Potential Controlling Factor for Microalgal Biodiversity.

Science.gov (United States)

Borchhardt, Nadine; Baum, Christel; Mikhailyuk, Tatiana; Karsten, Ulf

2017-01-01

In the present study the biodiversity of biological soil crusts (BSCs) formed by phototrophic organisms were investigated on Arctic Svalbard (Norway). These communities exert several important ecological functions and constitute a significant part of vegetation at high latitudes. Non-diatom eukaryotic microalgal species of BSCs from 20 sampling stations around Ny-Ålesund and Longyearbyen were identified by morphology using light microscopy, and the results revealed a high species richness with 102 species in total. 67 taxa belonged to Chlorophyta (31 Chlorophyceae and 36 Trebouxiophyceae), 13 species were Streptophyta (11 Klebsormidiophyceae and two Zygnematophyceae) and 22 species were Ochrophyta (two Eustigmatophyceae and 20 Xanthophyceae). Surprisingly, Klebsormidium strains belonging to clade G (Streptophyta), which were so far described from Southern Africa, could be determined at 5 sampling stations. Furthermore, comparative analyses of Arctic and Antarctic BSCs were undertaken to outline differences in species composition. In addition, a pedological analysis of BSC samples included C, N, S, TP (total phosphorus), and pH measurements to investigate the influence of soil properties on species composition. No significant correlation with these chemical soil parameters was confirmed but the results indicated that pH might affect the BSCs. In addition, a statistically significant influence of precipitation on species composition was determined. Consequently, water availability was identified as one key driver for BSC biodiversity in Arctic regions.

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase.

Science.gov (United States)

Wang, Jun; Liu, Xi; Wang, Xu-Dong; Dong, Tao; Zhao, Xing-Yu; Zhu, Dan; Mei, Yi-Yuan; Wu, Guo-Hua

2016-11-01

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7°C) and decrease of crystallizing point (3°C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from $212.3 to $14.6 per batch with the microreactor. Overall, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain

Science.gov (United States)

Pennanen; Fritze; Vanhala; Kiikkila; Neuvonen; Baath

1998-06-01

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found.

Evaluation of potential relationships between benthic community structure and toxic metals in Laizhou Bay.

Science.gov (United States)

Wu, Bin; Song, Jinming; Li, Xuegang

2014-10-15

The objective of the present study was to examine the relationships between benthic community structure and toxic metals using bivariate/multivariate techniques at 17 sediment locations in Laizhou Bay, North China. Sediment chemical data were evaluated against geochemical background values and sediment quality guidelines, which identified Cu and As as contaminants of concern with a moderate potential for adverse effects. Benthic community data were subjected to non-metric multidimensional scaling, which generated four groups of stations. Spearman rank correlation was then employed to explore the relationships between the major axes of heavy metals and benthic community structure. However, weak and insignificant correlations were found between these axes, indicating that contaminants of concern may not be the primary explanatory factors. Polychaeta were abundant in southern Laizhou Bay, serving as a warning regarding the health status of the ecosystem. Integrated sediment quality assessment showed sediments from northern central locations were impaired, displaying less diverse benthos and higher metal contamination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels?

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Roberts Norman B

2011-10-01

Full Text Available Abstract Background Aluminium (Al toxicity was frequent in the 1980s in patients ingesting Al containing phosphate binders (Alucaps whilst having HD using water potentially contaminated with Al. The aim of this study was to determine the risk of Al toxicity in HD patients receiving Alucaps but never exposed to contaminated dialysate water. Methods HD patients only treated with Reverse Osmosis(RO treated dialysis water with either current or past exposure to Alucaps were given standardised DFO tests. Post-DFO serum Al level > 3.0 μmol/L was defined to indicate toxic loads based on previous bone biopsy studies. Results 39 patients (34 anuric were studied. Mean dose of Alucap was 3.5 capsules/d over 23.0 months. Pre-DFO Al levels were > 1.0 μmol/L in only 2 patients and none were > 3.0 μmol/L. No patients had a post DFO Al levels > 3.0 μmol/L. There were no correlations between the serum Al concentrations (pre-, post- or the incremental rise after DFO administration and the total amount of Al ingested. No patients had unexplained EPO resistance or biochemical evidence of adynamic bone. Conclusions Although this is a small study, oral aluminium exposure was considerable. Yet no patients undergoing HD with RO treated water had evidence of Al toxicity despite doses equivalent to 3.5 capsules of Alucap for 2 years. The relationship between the DFO-Al results and the total amount of Al ingested was weak (R2 = 0.07 and not statistically significant. In an era of financial prudence, and in view of the recognised risk of excess calcium loading in dialysis patients, perhaps we should re-evaluate the risk of using Al-based phosphate binders in HD patients who remain uric.

Inhibitory activities of microalgal extracts against Epstein-Barr Virus (EBV antigen expression in lymphoblastoid cells

Directory of Open Access Journals (Sweden)

Koh Yih Yih

2014-01-01

Full Text Available The inhibitory activities of microalgal extracts against the expression of three EBV antigens, latent membrane protein (LMP1, Epstein-Barr nuclear antigen (EBNA1 and Z Epstein-Barr reactivation activator (ZEBRA were assessed by immunocytochemistry. The observation that the methanol extracts and their fractions from Ankistrodesmus convolutus, Synechococcus elongatus and Spirulina platensis exhibited inhibitory activity against EBV proteins in three Burkitt’s lymphoma cell lines at concentrations as low as 20 μg/ml suggests that microalgae could be a potential source of antiviral compounds against EBV.

Community Vitality: The Role of Community-Level Resilience Adaptation and Innovation in Sustainable Development

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Lenore Newman

2010-01-01

Full Text Available Community level action towards sustainable development has emerged as a key scale of intervention in the effort to address our many serious environmental issues. This is hindered by the large-scale destruction of both urban neighbourhoods and rural villages in the second half of the twentieth century. Communities, whether they are small or large, hubs of experimentation or loci of traditional techniques and methods, can be said to have a level of community vitality that acts as a site of resilience, adaptation and innovation in the face of environmental challenges. This paper outlines how community vitality acts as a cornerstone of sustainable development and suggests some courses for future research. A meta-case analysis of thirty-five Canadian communities reveals the characteristics of community vitality emerging from sustainable development experiments and its relationship to resilience, applied specifically to community development.

Nanocellulose size regulates microalgal flocculation and lipid metabolism

Science.gov (United States)

Yu, Sun Il; Min, Seul Ki; Shin, Hwa Sung

2016-01-01

Harvesting of microalgae is a cost-consuming step for biodiesel production. Cellulose has recently been studied as a biocompatible and inexpensive flocculant for harvesting microalgae via surface modifications such as cation-modifications. In this study, we demonstrated that cellulose nanofibrils (CNF) played a role as a microalgal flocculant via its network geometry without cation modification. Sulfur acid-treated tunicate CNF flocculated microalgae, but cellulose nanocrystals (CNC) did not. In addition, desulfurization did not significantly influence the flocculation efficiency of CNF. This mechanism is likely related to encapsulation of microalgae by nanofibrous structure formation, which is derived from nanofibrils entanglement and intra-hydrogen bonding. Moreover, flocculated microalgae were subject to mechanical stress resulting in changes in metabolism induced by calcium ion influx, leading to upregulated lipid synthesis. CNF do not require surface modifications such as cation modified CNC and flocculation is derived from network geometry related to nanocellulose size; accordingly, CNF is one of the least expensive cellulose-based flocculants ever identified. If this flocculant is applied to the biodiesel process, it could decrease the cost of harvest, which is one of the most expensive steps, while increasing lipid production. PMID:27796311

Microalgae based biorefinery: evaluation of oil extraction methods in terms of efficiency, costs, toxicity and energy in lab-scale

Directory of Open Access Journals (Sweden)

Ángel Darío González-Delgado

2013-06-01

Full Text Available Several alternatives of microalgal metabolites extraction and transformation are being studied for achieving the total utilization of this energy crop of great interest worldwide. Microalgae oil extraction is a key stage in microalgal biodiesel production chains and their efficiency affects significantly the global process efficiency. In this study, a comparison of five oil extraction methods in lab-scale was made taking as additional parameters, besides extraction efficiency, the costs of method performing, energy requirements, and toxicity of solvents used, in order to elucidate the convenience of their incorporation to a microalgae-based topology of biorefinery. Methods analyzed were Solvent extraction assisted with high speed homogenization (SHE, Continuous reflux solvent extraction (CSE, Hexane based extraction (HBE, Cyclohexane based extraction (CBE and Ethanol-hexane extraction (EHE, for this evaluation were used the microalgae strains Nannochloropsis sp., Guinardia sp., Closterium sp., Amphiprora sp. and Navicula sp., obtained from a Colombian microalgae bioprospecting. In addition, morphological response of strains to oil extraction methods was also evaluated by optic microscopy. Results shows that although there is not a unique oil extraction method which excels in all parameters evaluated, CSE, SHE and HBE appears as promising alternatives, while HBE method is shown as the more convenient for using in lab-scale and potentially scalable for implementation in a microalgae based biorefinery

High-throughput sequencing reveals microbial communities in drinking water treatment sludge from six geographically distributed plants, including potentially toxic cyanobacteria and pathogens.

Science.gov (United States)

Xu, Hangzhou; Pei, Haiyan; Jin, Yan; Ma, Chunxia; Wang, Yuting; Sun, Jiongming; Li, Hongmin

2018-04-10

The microbial community structures of drinking water treatment sludge (DWTS) generated for raw water (RW) from different locations and with different source types - including river water, lake water and reservoir water -were investigated using high-throughput sequencing. Because the unit operations in the six DWTPs were similar, community composition in fresh sludge may be determined by microbial community in the corresponding RW. Although Proteobacteria, Cyanobacteria, Bacteroidetes, Firmicutes, Verrucomicrobia, and Planctomycetes were the dominant phyla among the six DWTS samples, no single phylum exhibited similar abundance across all the samples, owing to differences in total phosphorus, chemical oxygen demand, Al, Fe, and chloride in RW. Three genera of potentially toxic cyanobacteria (Planktothrix, Microcystis and Cylindrospermopsis), and four potential pathogens (Escherichia coli, Bacteroides ovatus, Prevotella copri and Rickettsia) were found in sludge samples. Because proliferation of potentially toxic cyanobacteria and Rickettsia in RW was mainly affected by nutrients, while growth of Escherichia coli, Bacteroides ovatus and Prevotella copri in RW may be influenced by Fe, control of nutrients and Fe in RW is essential to decrease toxic cyanobacteria and pathogens in DWTS. Copyright © 2018 Elsevier B.V. All rights reserved.

Assessing sediment contamination using six toxicity assays

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Allen G. BURTON Jr.

2001-08-01

Full Text Available An evaluation of sediment toxicity at Lake Orta, Italy was conducted to compare a toxicity test battery of 6 assays and to evaluate the extent of sediment contamination at various sediment depths. Lake Orta received excessive loadings of copper and ammonia during the 1900’s until a large remediation effort was conducted in 1989-90 using lime addition. Since that time, the lake has shown signs of a steady recovery of biological communities. The study results showed acute toxicity still exists in sediments at a depth of 5 cm and greater. Assays that detected the highest levels of toxicity were two whole sediment exposures (7 d using Hyalella azteca and Ceriodaphnia dubia. The MicrotoxR assay using pore water was the third most sensitive assay. The Thamnotox, Rototox, Microtox solid phase, and Seed Germination-Root Elongation (pore and solid phase assays showed occasional to no toxicity. Based on similarity of responses and assay sensitivity, the two most useful assays were the C. dubia (or H. azteca and Microtox pore water. These assays were effective at describing sediment toxicity in a weight-of-evidence approach.

Comparative effects of parathion and chlorpyrifos on extracellular endocannabinoid levels in rat hippocampus: Influence on cholinergic toxicity

International Nuclear Information System (INIS)

Liu, Jing; Parsons, Loren; Pope, Carey

2013-01-01

Parathion (PS) and chlorpyrifos (CPF) are organophosphorus insecticides (OPs) that elicit acute toxicity by inhibiting acetylcholinesterase (AChE). Endocannabinoids (eCBs, N-arachidonoylethanolamine, AEA; 2-arachidonoylglycerol, 2AG) can modulate neurotransmission by inhibiting neurotransmitter release. We proposed that differential inhibition of eCB-degrading enzymes (fatty acid amide hydrolase, FAAH, and monoacylglycerol lipase, MAGL) by PS and CPF leads to differences in extracellular eCB levels and toxicity. Microdialysis cannulae were implanted into hippocampus of adult male rats followed by treatment with vehicle (peanut oil, 2 ml/kg, sc), PS (27 mg/kg) or CPF (280 mg/kg) 6–7 days later. Signs of toxicity, AChE, FAAH and MAGL inhibition, and extracellular levels of AEA and 2AG were measured 2 and 4 days later. Signs were noted in PS-treated rats but not in controls or CPF-treated rats. Cholinesterase inhibition was extensive in hippocampus with PS (89–90%) and CPF (78–83%) exposure. FAAH activity was also markedly reduced (88–91%) by both OPs at both time-points. MAGL was inhibited by both OPs but to a lesser degree (35–50%). Increases in extracellular AEA levels were noted after either PS (about 2-fold) or CPF (about 3-fold) while lesser treatment-related 2-AG changes were noted. The cannabinoid CB1 receptor antagonist/inverse agonist AM251 (3 mg/kg, ip) had no influence on functional signs after CPF but markedly decreased toxicity in PS-treated rats. The results suggest that extracellular eCBs levels can be markedly elevated by both PS and CPF. CB1-mediated signaling appears to play a role in the acute toxicity of PS but the role of eCBs in CPF toxicity remains unclear. - Highlights: • Chlorpyrifos and parathion both extensively inhibited hippocampal cholinesterase. • Functional signs were only noted with parathion. • Chlorpyrifos and parathion increased hippocampal extracellular anandamide levels. • 2-Arachidonoylglycerol levels were

Comparative effects of parathion and chlorpyrifos on extracellular endocannabinoid levels in rat hippocampus: Influence on cholinergic toxicity

Energy Technology Data Exchange (ETDEWEB)

Liu, Jing [Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (United States); Parsons, Loren [Committee on Neurobiology of Affective Disorders, The Scripps Research Institute, La Jolla, CA (United States); Pope, Carey, E-mail: carey.pope@okstate.edu [Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK (United States)

2013-11-01

Parathion (PS) and chlorpyrifos (CPF) are organophosphorus insecticides (OPs) that elicit acute toxicity by inhibiting acetylcholinesterase (AChE). Endocannabinoids (eCBs, N-arachidonoylethanolamine, AEA; 2-arachidonoylglycerol, 2AG) can modulate neurotransmission by inhibiting neurotransmitter release. We proposed that differential inhibition of eCB-degrading enzymes (fatty acid amide hydrolase, FAAH, and monoacylglycerol lipase, MAGL) by PS and CPF leads to differences in extracellular eCB levels and toxicity. Microdialysis cannulae were implanted into hippocampus of adult male rats followed by treatment with vehicle (peanut oil, 2 ml/kg, sc), PS (27 mg/kg) or CPF (280 mg/kg) 6–7 days later. Signs of toxicity, AChE, FAAH and MAGL inhibition, and extracellular levels of AEA and 2AG were measured 2 and 4 days later. Signs were noted in PS-treated rats but not in controls or CPF-treated rats. Cholinesterase inhibition was extensive in hippocampus with PS (89–90%) and CPF (78–83%) exposure. FAAH activity was also markedly reduced (88–91%) by both OPs at both time-points. MAGL was inhibited by both OPs but to a lesser degree (35–50%). Increases in extracellular AEA levels were noted after either PS (about 2-fold) or CPF (about 3-fold) while lesser treatment-related 2-AG changes were noted. The cannabinoid CB1 receptor antagonist/inverse agonist AM251 (3 mg/kg, ip) had no influence on functional signs after CPF but markedly decreased toxicity in PS-treated rats. The results suggest that extracellular eCBs levels can be markedly elevated by both PS and CPF. CB1-mediated signaling appears to play a role in the acute toxicity of PS but the role of eCBs in CPF toxicity remains unclear. - Highlights: • Chlorpyrifos and parathion both extensively inhibited hippocampal cholinesterase. • Functional signs were only noted with parathion. • Chlorpyrifos and parathion increased hippocampal extracellular anandamide levels. • 2-Arachidonoylglycerol levels were

1995 Toxic chemical release inventory: Emergency Planning and Community Right-to-Know Act of 1986, Section 313

International Nuclear Information System (INIS)

Mincey, S.L.

1996-08-01

Section 313 of the Emergency Planning and Community Right-To-Know Act (EPCRA) requires the annual submittal of toxic chemical release information to the U.S. Environmental Protection Agency.Executive Order 12856, 'Federal Compliance With Right-to-Know Laws and Pollution Prevention Requirements' extends the requirements of EPCRA to all Federal agencies. The following document is the August 1996 submittal of the Hanford Site Toxic Chemical Release Inventory report. Included is a Form R for ethylene glycol, the sole chemical used in excess of the established regulatory thresholds at the Hanford Site by the U.S. Department of Energy, Richland Operations Office and its contractors during Calendar Year 1995

Identification of overlapping communities and their hierarchy by locally calculating community-changing resolution levels

International Nuclear Information System (INIS)

Havemann, Frank; Heinz, Michael; Struck, Alexander; Gläser, Jochen

2011-01-01

We propose a new local, deterministic and parameter-free algorithm that detects fuzzy and crisp overlapping communities in a weighted network and simultaneously reveals their hierarchy. Using a local fitness function, the algorithm greedily expands natural communities of seeds until the whole graph is covered. The hierarchy of communities is obtained analytically by calculating resolution levels at which communities grow rather than numerically by testing different resolution levels. This analytic procedure is not only more exact than its numerical alternatives such as LFM and GCE but also much faster. Critical resolution levels can be identified by searching for intervals in which large changes of the resolution do not lead to growth of communities. We tested our algorithm on benchmark graphs and on a network of 492 papers in information science. Combined with a specific post-processing, the algorithm gives much more precise results on LFR benchmarks with high overlap compared to other algorithms and performs very similarly to GCE

Identification of overlapping communities and their hierarchy by locally calculating community-changing resolution levels

Science.gov (United States)

Havemann, Frank; Heinz, Michael; Struck, Alexander; Gläser, Jochen

2011-01-01

We propose a new local, deterministic and parameter-free algorithm that detects fuzzy and crisp overlapping communities in a weighted network and simultaneously reveals their hierarchy. Using a local fitness function, the algorithm greedily expands natural communities of seeds until the whole graph is covered. The hierarchy of communities is obtained analytically by calculating resolution levels at which communities grow rather than numerically by testing different resolution levels. This analytic procedure is not only more exact than its numerical alternatives such as LFM and GCE but also much faster. Critical resolution levels can be identified by searching for intervals in which large changes of the resolution do not lead to growth of communities. We tested our algorithm on benchmark graphs and on a network of 492 papers in information science. Combined with a specific post-processing, the algorithm gives much more precise results on LFR benchmarks with high overlap compared to other algorithms and performs very similarly to GCE.

Effects of pesticides on community composition and activity of sediment microbes - responses at various levels of microbial community organization

International Nuclear Information System (INIS)

Widenfalk, Anneli; Bertilsson, Stefan; Sundh, Ingvar; Goedkoop, Willem

2008-01-01

A freshwater sediment was exposed to the pesticides captan, glyphosate, isoproturon, and pirimicarb at environmentally relevant and high concentrations. Effects on sediment microorganisms were studied by measuring bacterial activity, fungal and total microbial biomass as community-level endpoints. At the sub-community level, microbial community structure was analysed (PLFA composition and bacterial 16S rRNA genotyping, T-RFLP). Community-level endpoints were not affected by pesticide exposure. At lower levels of microbial community organization, however, molecular methods revealed treatment-induced changes in community composition. Captan and glyphosate exposure caused significant shifts in bacterial community composition (as T-RFLP) at environmentally relevant concentrations. Furthermore, differences in microbial community composition among pesticide treatments were found, indicating that test compounds and exposure concentrations induced multidirectional shifts. Our study showed that community-level end points failed to detect these changes, underpinning the need for application of molecular techniques in aquatic ecotoxicology. - Molecular techniques revealed pesticide-induced changes at lower levels of microbial community organization that were not detected by community-level end points

Effects of pesticides on community composition and activity of sediment microbes - responses at various levels of microbial community organization

Energy Technology Data Exchange (ETDEWEB)

Widenfalk, Anneli [Department of Environmental Assessment, Swedish University of Agricultural Sciences, P.O. Box 7050, SE-750 07 Uppsala (Sweden)], E-mail: anneli.widenfalk@kemi.se; Bertilsson, Stefan [Limnology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvaegen 20, SE-752 36 Uppsala (Sweden); Sundh, Ingvar [Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7025, SE-750 07 Uppsala (Sweden); Goedkoop, Willem [Department of Environmental Assessment, Swedish University of Agricultural Sciences, P.O. Box 7050, SE-750 07 Uppsala (Sweden)

2008-04-15

A freshwater sediment was exposed to the pesticides captan, glyphosate, isoproturon, and pirimicarb at environmentally relevant and high concentrations. Effects on sediment microorganisms were studied by measuring bacterial activity, fungal and total microbial biomass as community-level endpoints. At the sub-community level, microbial community structure was analysed (PLFA composition and bacterial 16S rRNA genotyping, T-RFLP). Community-level endpoints were not affected by pesticide exposure. At lower levels of microbial community organization, however, molecular methods revealed treatment-induced changes in community composition. Captan and glyphosate exposure caused significant shifts in bacterial community composition (as T-RFLP) at environmentally relevant concentrations. Furthermore, differences in microbial community composition among pesticide treatments were found, indicating that test compounds and exposure concentrations induced multidirectional shifts. Our study showed that community-level end points failed to detect these changes, underpinning the need for application of molecular techniques in aquatic ecotoxicology. - Molecular techniques revealed pesticide-induced changes at lower levels of microbial community organization that were not detected by community-level end points.

2015 TRI National Analysis: Toxics Release Inventory Releases at Various Summary Levels

Science.gov (United States)

The TRI National Analysis is EPA's annual interpretation of TRI data at various summary levels. It highlights how toxic chemical wastes were managed, where toxic chemicals were released and how the 2015 TRI data compare to data from previous years. This dataset reports US state, county, large aquatic ecosystem, metro/micropolitan statistical area, and facility level statistics from 2015 TRI releases, including information on: number of 2015 TRI facilities in the geographic area and their releases (total, water, air, land); population information, including populations living within 1 mile of TRI facilities (total, minority, in poverty); and Risk Screening Environmental Indicators (RSEI) model related pounds, toxicity-weighted pounds, and RSEI score. The source of administrative boundary data is the 2013 cartographic boundary shapefiles. Location of facilities is provided by EPA's Facility Registry Service (FRS). Large Aquatic Ecosystems boundaries were dissolved from the hydrologic unit boundaries and codes for the United States, Puerto Rico, and the U.S. Virgin Islands. It was revised for inclusion in the National Atlas of the United States of America (November 2002), and updated to match the streams file created by the USGS National Mapping Division (NMD) for the National Atlas of the United States of America.

Acute Toxicity of Castor Oil Bean Extract and Tolerance Level of ...

African Journals Online (AJOL)

The experiment was carried out to determine the acute toxicity of raw castor oil bean (Ricinus communis) extract and the tolerance level of raw castor oil bean by broilers. The seeds were ground, defatted with petroleum ether and the residue was subjected to extraction with phosphate-buffered saline. The extract volume ...

Microalgal technology for remediation of CO{sub 2} from power plant flue gas: A techno-economic perspective

Energy Technology Data Exchange (ETDEWEB)

Kadam, K.L. [National Renewable Energy Lab., Golden, CO (United States)

1996-12-31

Power plants burning fossil fuels are a major source of CO{sub 2} which is implicated in global warming. Microalgal systems which photosynthetically assimilate carbon dioxide can be used for mitigation of this major greenhouse gas. A techno-economic model was developed for trapping carbon dioxide from flue gases by microalgae in outdoor ponds. The model also shows that algal lipid content and growth rate are both important for an economical process, but a trade-off exists between the two, i.e., a high lipid content and low growth rate combination can be as effective as a low lipid content and high growth rate combination. Hence, these two parameters may be treated as a composite parameter to be optimized to yield the least CO{sub 2} mitigation cost. Model predictions were also used to compare the microalgal technology with alternative technologies in terms of CO{sub 2} mitigation costs. Incorporating advances anticipated in the future into the design basis, the model yields a CO{sub 2} mitigation cost that is competitive with other CO{sub 2} remediation technologies currently being proposed. Furthermore, this technology also provides a lipid feedstock for producing a renewable fuel such as biodiesel. Deployment of this technology for CO{sub 2} mitigation looks attractive if research goals put forth by the model are achieved.

Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine

OpenAIRE

Parsaeimehr, Ali; Sun, Zhilan; Dou, Xiao; Chen, Yi-Feng

2015-01-01

Background Photoautotrophic microalgae are a promising avenue for sustained biodiesel production, but are compromised by low yields of biomass and lipids at present. We are developing a chemical approach to improve microalgal accumulation of feedstock lipids as well as high-value alpha-linolenic acid which in turn might provide a driving force for biodiesel production. Results We demonstrate the effectiveness of the small bioactive molecule ?acetylcholine? on accumulation of biomass, total li...

Potassium toxicity at low serum potassium levels with refeeding syndrome.

Science.gov (United States)

Vemula, Praveen; Abela, Oliver G; Narisetty, Keerthy; Rhine, David; Abela, George S

2015-01-01

Refeeding syndrome is a life-threatening condition occurring in severely malnourished patients after initiating feeding. Severe hypophosphatemia with reduced adenosine triphosphate production has been implicated, but little data are available regarding electrolyte abnormalities. In this case, we report electrocardiographic changes consistent with hyperkalemia during potassium replacement after a serum level increase from 1.9 to 2.9 mEq/L. This was reversed by lowering serum potassium back to 2.0 mEq/L. In conclusion, the patient with prolonged malnutrition became adapted to low potassium levels and developed potassium toxicity with replacement. Copyright © 2015 Elsevier Inc. All rights reserved.

Community Level Risk Factors for Maternal Mortality in Madagascar ...

African Journals Online (AJOL)

Previous work in this area uses individual or cross-country data to study maternal mortality, however, studying maternal mortality at the community level is imperative because this is the level at which most policy is implemented. The results show that longer travel time from the community to the hospital leads to a high level ...

Levels of macroelements and toxic elements in herbal teas

Directory of Open Access Journals (Sweden)

Mihaljev Željko A.

2015-01-01

Full Text Available A total of 14 diverse herbal teas were examined, including: yarrow, basil, St.John’s wort, peppermint, horsetail, nettle, thyme, corn silk, hibiscus, marshmallow, chamomile, rosehip, heather and wild mint. The samples were prepared using the method of microwave digestion, and measurements were performed by the use of inductively coupled plasma mass spectrometry (Cd, Hg, Pb, As, Sb; atomic absorption spectrometry (Mg; emission flame photometry (Ca, K, Na and spectrophotometry (P. Intervals of variation (mg/kg for macroelements were: Ca (2738-35399; P (1545-6264; Mg (1647-7816; Na (293-10629 and K (9683-33985, and for toxic elements: Cd (0.014-0.645; Hg (<0.001- 0.017; Pb (0.064-1.340; As (0.030-0.544 and Sb (0.004-0.068. In the three samples (yarrow and two St.John’s wort samples measured cadmium concentration was higher than the maximum level for dried herbs, recommended by WHO. Ward's hierarchical clustering method was performed with the aim of grouping herbal teas by the amount of toxic elements. [Projekat Ministarstva nauke Republike Srbije, br. TR31071

Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

International Nuclear Information System (INIS)

Hoess, S.; Ahlf, W.; Fahnenstich, C.; Gilberg, D.; Hollert, H.; Melbye, K.; Meller, M.; Hammers-Wirtz, M.; Heininger, P.; Neumann-Hensel, H.; Ottermanns, R.; Ratte, H.-T.

2010-01-01

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity. - Sediment-contact tests require toxicity thresholds based on their variability in native sediments with low-level contamination.

Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

Energy Technology Data Exchange (ETDEWEB)

Hoess, S., E-mail: hoess@ecossa.d [Ecossa, Giselastr. 6, 82319 Starnberg (Germany); Institute of Biodiversity - Network (IBN), Dreikronengasse 2, 93047 Regensburg (Germany); Ahlf, W., E-mail: ahlf@tu-harburg.d [Institute of Environmental Technology and Energy Economics, Technical University Hamburg-Harburg, Eissendorfer Str. 40, 21071 Hamburg (Germany); Fahnenstich, C. [Institute of Environmental Technology and Energy Economics, Technical University Hamburg-Harburg, Eissendorfer Str. 40, 21071 Hamburg (Germany); Gilberg, D., E-mail: d-gilberg@ect.d [ECT Oekotoxikologie, Boettgerstr. 2-14, 65439 Floersheim (Germany); Hollert, H., E-mail: henner.hollert@bio5.rwth-aachen.d [Department of Ecosystem Analysis, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Melbye, K. [Dr. Fintelmann and Dr. Meyer, Mendelssohnstr. 15D, 22761 Hamburg (Germany); Meller, M., E-mail: m-meller@ecotox-consult.d [ECT Oekotoxikologie, Boettgerstr. 2-14, 65439 Floersheim (Germany); Hammers-Wirtz, M., E-mail: hammers-wirtz@gaiac.rwth-aachen.d [Research Institute for Ecosystem Analysis and Assessment (gaiac), RWTH Aachen University, Worringerweg 1, 52056 Aachen (Germany); Heininger, P., E-mail: heininger@bafg.d [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56070 Koblenz (Germany); Neumann-Hensel, H., E-mail: hensel@fintelmann-meyer.d [Dr. Fintelmann and Dr. Meyer, Mendelssohnstr. 15D, 22761 Hamburg (Germany); Ottermanns, R., E-mail: ottermanns@bio5.rwth-aachen.d [Chair for Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Ratte, H.-T., E-mail: toni.ratte@bio5.rwth-aachen.d [Chair for Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany)

2010-09-15

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity. - Sediment-contact tests require toxicity thresholds based on their variability in native sediments with low-level contamination.

Perturbation of an arctic soil microbial community by metal nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Kumar, Niraj [Department of Biology, Queen' s University, Kingston, Ontario K7L 3N6 (Canada); Shah, Vishal [Department of Biology, Dowling College, Oakdale, NY 11769 (United States); Walker, Virginia K., E-mail: walkervk@queensu.ca [Department of Biology, Queen' s University, Kingston, Ontario K7L 3N6 (Canada); Department of Biology, School of Environmental Studies and Department of Microbiology and Immunology, Queen' s University, Kingston, Ontario K7L 3N6 (Canada)

2011-06-15

Highlights: {yields} Silver, copper and silica nanoparticles had an impact on arctic soil {yields} A microbial community toxicity indicator was developed {yields} Community surveys using pyrosequencing confirmed a shift in bacterial biodiversity {yields} Troublingly, silver nanoparticles were highly toxic to a plant beneficial bacterium - Abstract: Technological advances allowing routine nanoparticle (NP) manufacture have enabled their use in electronic equipment, foods, clothing and medical devices. Although some NPs have antibacterial activity, little is known about their environmental impact and there is no information on the influence of NPs on soil in the possibly vulnerable ecosystems of polar regions. The potential toxicity of 0.066% silver, copper or silica NPs on a high latitude (>78{sup o}N) soil was determined using community level physiological profiles (CLPP), fatty acid methyl ester (FAME) assays and DNA analysis, including sequencing and denaturing gradient gel electrophoresis (DGGE). The results of these different investigations were amalgamated in order to develop a community toxicity indicator, which revealed that of the three NPs examined, silver NPs could be classified as highly toxic to these arctic consortia. Subsequent culture-based studies confirmed that one of the community-identified plant-associating bacteria, Bradyrhizobium canariense, appeared to have a marked sensitivity to silver NPs. Thus, NP contamination of arctic soils particularly by silver NPs is a concern and procedures for mitigation and remediation of such pollution should be a priority for investigation.

Perturbation of an arctic soil microbial community by metal nanoparticles

International Nuclear Information System (INIS)

Kumar, Niraj; Shah, Vishal; Walker, Virginia K.

2011-01-01

Highlights: → Silver, copper and silica nanoparticles had an impact on arctic soil → A microbial community toxicity indicator was developed → Community surveys using pyrosequencing confirmed a shift in bacterial biodiversity → Troublingly, silver nanoparticles were highly toxic to a plant beneficial bacterium - Abstract: Technological advances allowing routine nanoparticle (NP) manufacture have enabled their use in electronic equipment, foods, clothing and medical devices. Although some NPs have antibacterial activity, little is known about their environmental impact and there is no information on the influence of NPs on soil in the possibly vulnerable ecosystems of polar regions. The potential toxicity of 0.066% silver, copper or silica NPs on a high latitude (>78 o N) soil was determined using community level physiological profiles (CLPP), fatty acid methyl ester (FAME) assays and DNA analysis, including sequencing and denaturing gradient gel electrophoresis (DGGE). The results of these different investigations were amalgamated in order to develop a community toxicity indicator, which revealed that of the three NPs examined, silver NPs could be classified as highly toxic to these arctic consortia. Subsequent culture-based studies confirmed that one of the community-identified plant-associating bacteria, Bradyrhizobium canariense, appeared to have a marked sensitivity to silver NPs. Thus, NP contamination of arctic soils particularly by silver NPs is a concern and procedures for mitigation and remediation of such pollution should be a priority for investigation.

Ebola-related stigma in Ghana: Individual and community level determinants.

Science.gov (United States)

Tenkorang, Eric Y

2017-06-01

Although Ebola-related stigmatization continues to undermine efforts to re-integrate survivors, few studies have examined what influences such stigmatizing attitudes. This paper explores the effects of both individual- and community-level factors on Ebola-related stigma in Ghana. Data were collected from a cross-section of 800 respondents, nested within 40 communities in the Greater Accra Region of Ghana. Multi-level modelling was employed for analysis. Both individual- and community-level factors were significant determinants of stigma. Respondents who endorsed myths about Ebola were significantly more likely to also endorse Ebola-related stigma. Similarly, those who were worried about a potential outbreak of Ebola in the future, had moderate risk perceptions of contracting Ebola, had primary and secondary education, and were not confident of the quality of health care in the event of an outbreak, were more likely to endorse Ebola-related stigma. Knowledge of Ebola was significant at the community level, but not at the individual level. Communities with more knowledge were less likely to endorse Ebola-related stigma. These findings underscore the need to increase the knowledge base while countering myths that undermine preventive behaviours to fight Ebola-related stigma. It is equally important to adopt multi-level interventions that emphasize community-based strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Collaborative Study of Disproportionate Chemical Risks in Seven Delaware Communities

Science.gov (United States)

Dryden, O.; Goldman, G. T.; White, R.; Moore, D.; Roberts, M.; Thomas, J.; Johnson, C.

2017-12-01

Studies have found that, compared to national averages, a significantly greater percentage of Blacks (African-Americans), Latinos (Hispanics), and people at or near poverty levels tend to live near industrial facilities that use large quantities of toxic chemicals and present a risk of major chemical disasters with potentially severe consequences for nearby communities. The Union of Concerned Scientists, the Environmental Justice Health Alliance for Chemical Policy Reform, and Delaware Concerned Residents for Environmental Justice collaborated on a study to examine the potential for cumulative impacts from health and safety risks for seven Delaware communities with a percentage of people of color and/or poverty levels greater than the Delaware average located along an industrial corridor in the northern portion of Delaware's New Castle County. These risks include close proximity to major industrial sources, as well as facilities that use large quantities of toxic, flammable or explosive chemicals and pose a high risk of a major chemical release or catastrophic incident. Additionally, proximity to contaminated waste sites was assessed, as well as the risk of cancer and potential for respiratory disease impacts from exposure to toxic air pollution. We found that people in these seven communities face a substantial cumulative health risk from exposure to toxic air pollution, proximity to polluting industrial facilities and hazardous chemical facilities, as well as contaminated waste sites. These health risks are substantially greater when compared to a wealthier and predominantly White Delaware community and for Delaware as a whole. Significant and expedited improvements in regulatory and public policy are needed at the national, state, and municipal levels to address the health and well-being of at-risk communities in Delaware and elsewhere.

Comparison of Toxicities to Vibrio fischeri and Fish Based on Discrimination of Excess Toxicity from Baseline Level

Science.gov (United States)

Wang, Xiao H.; Yu, Yang; Huang, Tao; Qin, Wei C.; Su, Li M.; Zhao, Yuan H.

2016-01-01

Investigations on the relationship of toxicities between species play an important role in the understanding of toxic mechanisms to environmental organisms. In this paper, the toxicity data of 949 chemicals to fish and 1470 chemicals to V. fischeri were used to investigate the modes of action (MOAs) between species. The results show that although there is a positive interspecies correlation, the relationship is poor. Analysis on the excess toxicity calculated from toxic ratios (TR) shows that many chemicals have close toxicities and share the same MOAs between the two species. Linear relationships between the toxicities and octanol/water partition coefficient (log KOW) for baseline and less inert compounds indicate that the internal critical concentrations (CBRs) approach a constant both to fish and V. fischeri for neutral hydrophobic compounds. These compounds share the same toxic mechanisms and bio-uptake processes between species. On the other hand, some hydrophilic compounds exhibit different toxic effects with greatly different log TR values between V. fischeri and fish species. These hydrophilic compounds were identified as reactive MOAs to V. fischeri, but not to fish. The interspecies correlation is improved by adding a hydrophobic descriptor into the correlation equation. This indicates that the differences in the toxic ratios between fish and V. fischeri for these hydrophilic compounds can be partly attributed to the differences of bioconcentration between the two species, rather than the differences of reactivity with the target macromolecules. These hydrophilic compounds may more easily pass through the cell membrane of V. fischeri than the gill and skin of fish, react with the target macromolecules and exhibit excess toxicity. The compounds with log KOW > 7 exhibiting very low toxicity (log TR toxicity and MOAs. PMID:26901437

Biotechnological Screening of Microalgal and Cyanobacterial Strains for Biogas Production and Antibacterial and Antifungal Effects

Directory of Open Access Journals (Sweden)

Opayi Mudimu

2014-05-01

Full Text Available Microalgae and cyanobacteria represent a valuable natural resource for the generation of a large variety of chemical substances that are of interest for medical research, can be used as additives in cosmetics and food production, or as an energy source in biogas plants. The variety of potential agents and the use of microalgae and cyanobacteria biomass for the production of these substances are little investigated and not exploited for the market. Due to the enormous biodiversity of microalgae and cyanobacteria, they hold great promise for novel products. In this study, we investigated a large number of microalgal and cyanobacterial strains from the Culture Collection of Algae at Göttingen University (SAG with regard to their biomass and biogas production, as well antibacterial and antifungal effects. Our results demonstrated that microalgae and cyanobacteria are able to generate a large number of economically-interesting substances in different quantities dependent on strain type. The distribution and quantity of some of these components were found to reflect phylogenetic relationships at the level of classes. In addition, between closely related species and even among multiple isolates of the same species, the productivity may be rather variable.

Toxicity of algal-derived aldehydes to two invertebrate species: Do heavy metal pollutants have a synergistic effect?

Energy Technology Data Exchange (ETDEWEB)

Taylor, Rebecca L. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom)]. E-mail: r.l.taylor@ncl.ac.uk; Caldwell, Gary S. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom); Bentley, Matthew G. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom)

2005-08-15

The recent discovery of the production of anti-proliferative aldehydes in a variety of microalgal species has lead to considerable investigation into the effects of these toxins on aquatic invertebrates. Studies have, however, rarely considered the impact pollutants may have on grazer responses to algal toxins. In this study, the acute toxicities of five aldehydes to the rotifer Brachionus plicatilis and nauplii of the brine shrimp Artemia salina are examined using immersion assays. In addition, the effect of a representative of these aldehydes in the presence of sub-lethal levels of heavy metals was examined. B. plicatilis generally showed greater sensitivity to the aldehydes than A. salina. The polyunsaturated 2-trans,4-trans-decadienal was the most toxic to both species having 24 h LD{sub 50} values of 7 and 20 {mu}M for B. plicatilis and A. salina, respectively. The remaining aldehydes had different orders of toxicity for the two species with a stronger relationship observed between mortality and aldehyde carbon-chain length for A. salina whereas B. plicatilis mortality showed a stronger dependence on the presence of carbon-carbon double bonds in the aldehydes. The presence of 1 {mu}M of copper sulphate in solutions of decadienal resulted in the reduction of the 24 h LD{sub 50} of decadienal by approximately a third for both species. 1 {mu}M of copper chloride in solutions of decadienal reduced the 24 h LD{sub 50} of decadienal to A. salina nauplii by approximately 11% and 1 {mu}M zinc sulphate caused a reduction of only 3%. Pre-exposure of the organisms to 1 {mu}M copper sulphate had no significant impact on their subsequent mortality in decadienal. The ecological implications and the possible mechanisms for the action of copper sulphate on the response of organisms to decadienal are discussed.

Toxicity of algal-derived aldehydes to two invertebrate species: Do heavy metal pollutants have a synergistic effect?

International Nuclear Information System (INIS)

Taylor, Rebecca L.; Caldwell, Gary S.; Bentley, Matthew G.

2005-01-01

The recent discovery of the production of anti-proliferative aldehydes in a variety of microalgal species has lead to considerable investigation into the effects of these toxins on aquatic invertebrates. Studies have, however, rarely considered the impact pollutants may have on grazer responses to algal toxins. In this study, the acute toxicities of five aldehydes to the rotifer Brachionus plicatilis and nauplii of the brine shrimp Artemia salina are examined using immersion assays. In addition, the effect of a representative of these aldehydes in the presence of sub-lethal levels of heavy metals was examined. B. plicatilis generally showed greater sensitivity to the aldehydes than A. salina. The polyunsaturated 2-trans,4-trans-decadienal was the most toxic to both species having 24 h LD 50 values of 7 and 20 μM for B. plicatilis and A. salina, respectively. The remaining aldehydes had different orders of toxicity for the two species with a stronger relationship observed between mortality and aldehyde carbon-chain length for A. salina whereas B. plicatilis mortality showed a stronger dependence on the presence of carbon-carbon double bonds in the aldehydes. The presence of 1 μM of copper sulphate in solutions of decadienal resulted in the reduction of the 24 h LD 50 of decadienal by approximately a third for both species. 1 μM of copper chloride in solutions of decadienal reduced the 24 h LD 50 of decadienal to A. salina nauplii by approximately 11% and 1 μM zinc sulphate caused a reduction of only 3%. Pre-exposure of the organisms to 1 μM copper sulphate had no significant impact on their subsequent mortality in decadienal. The ecological implications and the possible mechanisms for the action of copper sulphate on the response of organisms to decadienal are discussed

Suicide prevention as a community development process: understanding circumpolar youth suicide prevention through community level outcomes.

Science.gov (United States)

Allen, James; Mohatt, Gerald; Fok, Carlotta Ching Ting; Henry, David

2009-06-01

Community-based models have become increasingly prominent in prevention, and have special relevance for suicide prevention in circumpolar Indigenous communities. It follows that outcomes from circumpolar suicide prevention programs might be more completely understood at the community level. We present here a methodology for analysis at this level. This paper seeks to understand a cultural prevention program for rural Yup'ik youth in Alaska targeting suicide and co-occurring alcohol abuse as a community development process through changes at the community level. Quasi-experimental design with assessment at pre- and post-intervention or at 4 time points. The community development process for this project began in October 2004. The first program baseline assessment began in November 2006, prior to prevention activities with youth and parents, and the post-intervention assessment concluded in March 2008. Five key informants pre- and post-intervention completed a community readiness assessment, which is a structured procedure assessing a community's awareness of suicide as an issue and its, organizational readiness for prevention programming. Forty-three adult caregivers or sponsors of youth in the prevention program completed an assessment of behaviours that contributed to community protective factors from youth suicide and alcohol abuse at 4 time points before, during and after the intervention. The 54 youth who participated in the prevention program completed an assessment of community protective factors, also at 4 time points before, during and after the intervention. The community protective factors from suicide that were assessed included safety, enforcement of alcohol prohibitions, role models, support and opportunities for youth. Community readiness for the prevention efforts increased to new developmental stages of readiness post-intervention, and a trend in the data suggested community protective factors increased in the amount of protective behaviours

Introducing Toxics

Directory of Open Access Journals (Sweden)

David C. Bellinger

2013-04-01

Full Text Available With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present their work in as much detail as they wish. Toxics will publish original research papers, conventional reviews, meta-analyses, short communications, theoretical papers, case reports, commentaries and policy perspectives, and book reviews (Book reviews will be solicited and should not be submitted without invitation. Toxins and toxicants concern individuals from a wide range of disciplines, and Toxics is interested in receiving papers that represent the full range of approaches applied to their study, including in vitro studies, studies that use experimental animal or non-animal models, studies of humans or other biological populations, and mathematical modeling. We are excited to get underway and look forward to working with authors in the scientific and medical communities and providing them with a novel venue for sharing their work. [...

Environmental levels, toxicity and human exposure to tributyltin (TBT)-contaminated marine environment. a review. b_antizar@hotmail.com.

Science.gov (United States)

Antizar-Ladislao, Blanca

2008-02-01

Tributyltin (TBT) is a toxic chemical used for various industrial purposes such as slime control in paper mills, disinfection of circulating industrial cooling waters, antifouling agents, and the preservation of wood. Due to its widespread use as an antifouling agent in boat paints, TBT is a common contaminant of marine and freshwater ecosystems exceeding acute and chronic toxicity levels. TBT is the most significant pesticide in marine and freshwaters in Europe and consequently its environmental level, fate, toxicity and human exposure are of current concern. Thus, the European Union has decided to specifically include TBT compounds in its list of priority compounds in water in order to control its fate in natural systems, due to their toxic, persistent, bioaccumulative and endocrine disruptive characteristics. Additionally, the International Maritime Organization has called for a global treaty that bans the application of TBT-based paints starting 1 of January 2003, and total prohibition by 1 of January 2008. This paper reviews the state of the science regarding TBT, with special attention paid to the environmental levels, toxicity, and human exposure. TBT compounds have been detected in a number of environmental samples. In humans, organotin compounds have been detected in blood and in the liver. As for other persistent organic pollutants, dietary intake is most probably the main route of exposure to TBT compounds for the general population. However, data concerning TBT levels in foodstuffs are scarce. It is concluded that investigations on experimental toxicity, dietary intake, potential human health effects and development of new sustainable technologies to remove TBT compounds are clearly necessary.

Australia’s first national level quantitative environmental justice assessment of industrial air pollution

International Nuclear Information System (INIS)

Chakraborty, Jayajit; Green, Donna

2014-01-01

This study presents the first national level quantitative environmental justice assessment of industrial air pollution in Australia. Specifically, our analysis links the spatial distribution of sites and emissions associated with industrial pollution sources derived from the National Pollution Inventory, to Indigenous status and social disadvantage characteristics of communities derived from Australian Bureau of Statistics indicators. Our results reveal a clear national pattern of environmental injustice based on the locations of industrial pollution sources, as well as volume, and toxicity of air pollution released at these locations. Communities with the highest number of polluting sites, emission volume, and toxicity-weighted air emissions indicate significantly greater proportions of Indigenous population and higher levels of socio-economic disadvantage. The quantities and toxicities of industrial air pollution are particularly higher in communities with the lowest levels of educational attainment and occupational status. These findings emphasize the need for more detailed analysis in specific regions and communities where socially disadvantaged groups are disproportionately impacted by industrial air pollution. Our empirical findings also underscore the growing necessity to incorporate environmental justice considerations in environmental planning and policy-making in Australia. (paper)

Place, health, and community attachment: Is community capacity associated with self-rated health at the individual level?

Science.gov (United States)

Lovell, Sarah A; Gray, Andrew R; Boucher, Sara E

2017-12-01

Community-level interventions dominate contemporary public health responses to health inequalities as a lack of political will has discouraged action at a structural level. Health promoters commonly leverage community capacity to achieve programme goals, yet the health implications of low community capacity are unknown. In this study, we analyse perceptions of community capacity at the individual-level to explore how place-based understandings of identity and connectedness are associated with self-rated health. We examine associations between individual community capacity, self-rated health and income using a cross-sectional survey that was disseminated to 303 residents of four small (populations 1500-2000) New Zealand towns. Evidence indicating a relationship between individual community capacity and self-reported health was unconvincing once the effects of income were incorporated. That is, people who rated their community's capacity higher did not have better self-rated health. Much stronger evidence supported the relationship between income and both higher individual community capacity and higher self-rated health. We conclude that individual community capacity may mediate the positive association between income and health, however, overall we find no evidence suggesting that intervening to enhance individual community capacity is likely to improve health outcomes.

Adolescent alcohol use reflects community-level alcohol consumption irrespective of parental drinking

DEFF Research Database (Denmark)

Bendtsen, Pernille; Damsgaard, Mogens Trab; Tolstrup, Janne Schurmann

2013-01-01

Risk factors for adolescent alcohol use are typically conceptualized at the individual level, and school- and community-level risk factors have received little attention. Based on the theoretical understanding of youth alcohol consumption as a reflection of community social practice, we analyzed...... whether adolescent drunkenness was related to community-level adult alcohol use (AAC), when taking individual and school-level risk factors for drunkenness into account. Furthermore, we investigated whether the association between community-level AAC and adolescent drunkenness was attenuated after...

Toxic Stress: Effects, Prevention and Treatment

Directory of Open Access Journals (Sweden)

Hillary A. Franke

2014-11-01

Full Text Available Children who experience early life toxic stress are at risk of long-term adverse health effects that may not manifest until adulthood. This article briefly summarizes the findings in recent studies on toxic stress and childhood adversity following the publication of the American Academy of Pediatrics (AAP Policy Report on the effects of toxic stress. A review of toxic stress and its effects is described, including factors of vulnerability, resilience, and the relaxation response. An integrative approach to the prevention and treatment of toxic stress necessitates individual, community and national focus.

Spatial predictions at the community level

DEFF Research Database (Denmark)

D'Amen, Manuela; Rahbek, Carsten; Zimmermann, Niklaus E.

2017-01-01

of communities, with a particular focus on species richness, composition, relative abundance and related attributes. We first briefly describe the concepts and theories that span the different drivers of species assembly. A combination of abiotic processes and biotic mechanisms are thought to influence...... the community assembly process. In this review, we describe four categories of drivers: (i) historical and evolutionary, (ii) environmental, (iii) biotic, and (iv) stochastic. We discuss the different modelling approaches proposed or applied at the community level and examine them from different standpoints, i......A fundamental goal of ecological research is to understand and model how processes generate patterns so that if conditions change, changes in the patterns can be predicted. Different approaches have been proposed for modelling species assemblage, but their use to predict spatial patterns of species...

Sense of community in Hong Kong: relations with community-level characteristics and residents' well-being.

Science.gov (United States)

Mak, Winnie W S; Cheung, Rebecca Y M; Law, Lawrence S C

2009-09-01

Sense of community (SOC) has been one of the most studied topics in community psychology. However, no empirical study to date has investigated SOC in Hong Kong and its relations with community characteristics and residents' psychological well-being. A representative sample of 941 Hong Kong Chinese based on a randomized household survey was conducted in all 18 districts in Hong Kong. Results of hierarchical linear modeling indicated that SOC was not associated with sociodemographic indicators on both the individual-level (i.e., gender, age, family income, education level, type of residence, and area-to-capita ratio of residence) and the community-level (i.e., proportion of individuals with tertiary education, median family income, ownership of residence, population density, and resident stability). SOC was negatively related to daily hassles and positively with social support and quality of life. Conceptualization of SOC in Hong Kong was discussed.

Toxic releases and risk disparity: a spatiotemporal model of industrial ecology and social empowerment.

Science.gov (United States)

Aoyagi, Hannah; Ogunseitan, Oladele A

2015-06-02

Information-based regulations (IBRs) are founded on the theoretical premise that public participation in accomplishing policy goals is empowered by open access to information. Since its inception in 1988, the Toxics Release Inventory (TRI) has provided the framework and regulatory impetus for the compilation and distribution of data on toxic releases associated with industrial development, following the tenets of IBR. As TRI emissions are reputed to disproportionately affect low-income communities, we investigated how demographic characteristics are related to change in TRI emissions and toxicity risks between 1989 and 2002, and we sought to identify factors that predict these changes. We used local indicators of spatial association (LISA) maps and spatial regression techniques to study risk disparity in the Los Angeles urban area. We also surveyed 203 individuals in eight communities in the same region to measure the levels of awareness of TRI, attitudes towards air pollution, and general environmental risk. We discovered, through spatial lag models, that changes in gross and toxic emissions are related to community ethnic composition, poverty level, home ownership, and base 1989 emissions (R-square=0.034-0.083). We generated a structural equation model to explain the determinants of social empowerment to act on the basis of environmental information. Hierarchical confirmatory factor analysis (HCFA) supports the theoretical model that individual empowerment is predicted by risk perception, worry, and awareness (Chi-square=63.315, p=0.022, df=42). This study provides strong evidence that spatiotemporal changes in regional-scale environmental risks are influenced by individual-scale empowerment mediated by IBRs.

Toxic Releases and Risk Disparity: A Spatiotemporal Model of Industrial Ecology and Social Empowerment

Directory of Open Access Journals (Sweden)

Hannah Aoyagi

2015-06-01

Full Text Available Information-based regulations (IBRs are founded on the theoretical premise that public participation in accomplishing policy goals is empowered by open access to information. Since its inception in 1988, the Toxics Release Inventory (TRI has provided the framework and regulatory impetus for the compilation and distribution of data on toxic releases associated with industrial development, following the tenets of IBR. As TRI emissions are reputed to disproportionately affect low-income communities, we investigated how demographic characteristics are related to change in TRI emissions and toxicity risks between 1989 and 2002, and we sought to identify factors that predict these changes. We used local indicators of spatial association (LISA maps and spatial regression techniques to study risk disparity in the Los Angeles urban area. We also surveyed 203 individuals in eight communities in the same region to measure the levels of awareness of TRI, attitudes towards air pollution, and general environmental risk. We discovered, through spatial lag models, that changes in gross and toxic emissions are related to community ethnic composition, poverty level, home ownership, and base 1989 emissions (R-square = 0.034–0.083. We generated a structural equation model to explain the determinants of social empowerment to act on the basis of environmental information. Hierarchical confirmatory factor analysis (HCFA supports the theoretical model that individual empowerment is predicted by risk perception, worry, and awareness (Chi-square = 63.315, p = 0.022, df = 42. This study provides strong evidence that spatiotemporal changes in regional-scale environmental risks are influenced by individual-scale empowerment mediated by IBRs.

Amendment in phosphorus levels moderate the chromium toxicity in Raphanus sativus L. as assayed by antioxidant enzymes activities.

Science.gov (United States)

Sayantan, D; Shardendu

2013-09-01

Chromium (Z=24), a d-block element, is a potent carcinogen, whereas phosphorus is an essential and limiting nutrient for the plant growth and development. This study undertakes the role of phosphorus in moderating the chromium toxicity in Raphanus sativus L., as both of them compete with each other during the uptake process. Two-factor complete randomized experiment (5 chromium × 5 phosphorus concentrations) was conducted for twenty eight days in green house. The individuals of R. sativus were grown in pots supplied with all essential nutrients. The toxic effects of chromium and the moderation of toxicity due to phosphorus amendment were determined as accumulation of chromium, nitrogen, phosphorus in root tissues and their effects were also examined in the changes in biomass, chlorophyll and antioxidant enzyme levels. Cr and N accumulation were almost doubled at the highest concentration of Cr supply, without any P amendment, whereas at the highest P concentration (125 mM), the accumulation was reduced to almost half. A significant reduction in toxic effects of Cr was determined as there was three-fold increase in total chlorophyll and biomass at the highest P amendment. Antioxidant enzymes like superoxide dismutase, catalase, peroxidase and lipid peroxidation were analyzed at various levels of Cr each amended with five levels of P. It was observed that at highest level of P amendment, the reduction percentage in toxicity was 33, 44, 39 and 44, correspondingly. Conclusively, the phosphorus amendment moderates the toxicity caused by the supplied chromium in R. sativus. This finding can be utilized to develop a novel technology for the amelioration of chromium stressed fields. Copyright © 2013 Elsevier Inc. All rights reserved.

Avoiding toxic levels of essential minerals: a forgotten factor in deer diet preferences.

Science.gov (United States)

Ceacero, Francisco; Landete-Castillejos, Tomás; Olguín, Augusto; Miranda, María; García, Andrés; Martínez, Alberto; Cassinello, Jorge; Miguel, Valentín; Gallego, Laureano

2015-01-01

Ungulates select diets with high energy, protein, and sodium contents. However, it is scarcely known the influence of essential minerals other than Na in diet preferences. Moreover, almost no information is available about the possible influence of toxic levels of essential minerals on avoidance of certain plant species. The aim of this research was to test the relative importance of mineral content of plants in diet selection by red deer (Cervus elaphus) in an annual basis. We determined mineral, protein and ash content in 35 common Mediterranean plant species (the most common ones in the study area). These plant species were previously classified as preferred and non-preferred. We found that deer preferred plants with low contents of Ca, Mg, K, P, S, Cu, Sr and Zn. The model obtained was greatly accurate identifying the preferred plant species (91.3% of correct assignments). After a detailed analysis of these minerals (considering deficiencies and toxicity levels both in preferred and non-preferred plants) we suggest that the avoidance of excessive sulphur in diet (i.e., selection for plants with low sulphur content) seems to override the maximization for other nutrients. Low sulphur content seems to be a forgotten factor with certain relevance for explaining diet selection in deer. Recent studies in livestock support this conclusion, which is highlighted here for the first time in diet selection by a wild large herbivore. Our results suggest that future studies should also take into account the toxicity levels of minerals as potential drivers of preferences.

Place, health, and community attachment: Is community capacity associated with self-rated health at the individual level?

Directory of Open Access Journals (Sweden)

Sarah A. Lovell

2017-12-01

Full Text Available Community-level interventions dominate contemporary public health responses to health inequalities as a lack of political will has discouraged action at a structural level. Health promoters commonly leverage community capacity to achieve programme goals, yet the health implications of low community capacity are unknown. In this study, we analyse perceptions of community capacity at the individual-level to explore how place-based understandings of identity and connectedness are associated with self-rated health. We examine associations between individual community capacity, self-rated health and income using a cross-sectional survey that was disseminated to 303 residents of four small (populations 1500–2000 New Zealand towns. Evidence indicating a relationship between individual community capacity and self-reported health was unconvincing once the effects of income were incorporated. That is, people who rated their community's capacity higher did not have better self-rated health. Much stronger evidence supported the relationship between income and both higher individual community capacity and higher self-rated health. We conclude that individual community capacity may mediate the positive association between income and health, however, overall we find no evidence suggesting that intervening to enhance individual community capacity is likely to improve health outcomes.

Effect of microalgal treatments on pesticides in water.

Science.gov (United States)

Hultberg, Malin; Bodin, Hristina; Ardal, Embla; Asp, Håkan

2016-01-01

The effect of the microalgae Chlorella vulgaris on a wide range of different pesticides in water was studied. Treatments included short-term exposure (1 h) to living and dead microalgal biomass and long-term exposure (4 days) to actively growing microalgae. The initial pesticide concentration was 63.5 ± 3.9 µg L(-1). There was no significant overall reduction of pesticides after short-term exposure. A significant reduction of the total amount of pesticides was achieved after the long-term exposure to growing microalgae (final concentration 29.7 ± 1.0 µg L(-1)) compared with the long-term control (37.0 ± 1.2 µg L(-1)). The concentrations of 10 pesticides out of 38 tested were significantly lowered in the long-term algal treatment. A high impact of abiotic factors such as sunlight and aeration for pesticide reduction was observed when the initial control (63.5 ± 3.9 µg L(-1)) and the long-term control (37.0 ± 1.2 µg L(-1)) were compared. The results suggest that water treatment using microalgae, natural inhabitants of polluted surface waters, could be further explored not only for removal of inorganic nutrients but also for removal of organic pollutants in water.

Direct quantification of fatty acids in wet microalgal and yeast biomass via a rapid in situ fatty acid methyl ester derivatization approach.

Science.gov (United States)

Dong, Tao; Yu, Liang; Gao, Difeng; Yu, Xiaochen; Miao, Chao; Zheng, Yubin; Lian, Jieni; Li, Tingting; Chen, Shulin

2015-12-01

Accurate determination of fatty acid contents is routinely required in microalgal and yeast biofuel studies. A method of rapid in situ fatty acid methyl ester (FAME) derivatization directly from wet fresh microalgal and yeast biomass was developed in this study. This method does not require prior solvent extraction or dehydration. FAMEs were prepared with a sequential alkaline hydrolysis (15 min at 85 °C) and acidic esterification (15 min at 85 °C) process. The resulting FAMEs were extracted into n-hexane and analyzed using gas chromatography. The effects of each processing parameter (temperature, reaction time, and water content) upon the lipids quantification in the alkaline hydrolysis step were evaluated with a full factorial design. This method could tolerate water content up to 20% (v/v) in total reaction volume, which equaled up to 1.2 mL of water in biomass slurry (with 0.05-25 mg of fatty acid). There were no significant differences in FAME quantification (p>0.05) between the standard AOAC 991.39 method and the proposed wet in situ FAME preparation method. This fatty acid quantification method is applicable to fresh wet biomass of a wide range of microalgae and yeast species.

Toxic effects of pesticide mixtures at a molecular level: Their relevance to human health

International Nuclear Information System (INIS)

Hernández, Antonio F.; Parrón, Tesifón; Tsatsakis, Aristidis M.; Requena, Mar; Alarcón, Raquel; López-Guarnido, Olga

2013-01-01

Highlights: ► Toxic effects of pesticide mixtures can be independent, dose addition or interaction. ► Metabolic interactions involve inhibition or induction of detoxifying enzymes. ► Organophosphates can potentiate pyrethroid, carbaryl and triazine toxicity. ► Synergism occurs when two active pesticides elicit greater than additive toxicity. ► Endocrine disruptors have the potential for additivity rather than synergism. - Abstract: Pesticides almost always occur in mixtures with other ones. The toxicological effects of low-dose pesticide mixtures on the human health are largely unknown, although there are growing concerns about their safety. The combined toxicological effects of two or more components of a pesticide mixture can take one of three forms: independent, dose addition or interaction. Not all mixtures of pesticides with similar chemical structures produce additive effects; thus, if they act on multiple sites their mixtures may produce different toxic effects. The additive approach also fails when evaluating mixtures that involve a secondary chemical that changes the toxicokinetics of the pesticide as a result of its increased activation or decreased detoxification, which is followed by an enhanced or reduced toxicity, respectively. This review addresses a number of toxicological interactions of pesticide mixtures at a molecular level. Examples of such interactions include the postulated mechanisms for the potentiation of pyrethroid, carbaryl and triazine herbicides toxicity by organophosphates; how the toxicity of some organophosphates can be potentiated by other organophosphates or by previous exposure to organochlorines; the synergism between pyrethroid and carbamate compounds and the antagonism between triazine herbicides and prochloraz. Particular interactions are also addressed, such as those of pesticides acting as endocrine disruptors, the cumulative toxicity of organophosphates and organochlorines resulting in estrogenic effects and the

Proceedings of the 36. annual aquatic toxicity workshop

International Nuclear Information System (INIS)

Martel, L.; Triffault-Bouchet, G.; Fournier, M.; Campbell, P.G.C.; Pellerin, J.; Lacroix, E.; Burridge, L.E.

2010-01-01

This workshop was held to discuss topics related to aquatic and environmental toxicology. Principles, issues, and recent innovations in aquatic toxicology were reviewed. New developments in environmental monitoring were discussed, as well as issues related to environmental regulation. The workshop was attended by a range of stakeholders from governments, universities, and industry. The sessions were entitled: legacy contaminants 1 organics; nanotoxicology; environmental effects monitoring; oil sands; BFR and other emerging contaminants; biomarkers; neuro and endocrine disrupting compounds; remediation of degraded aquatic environments; legacy contaminants 2 hydrocarbons; waterborne and diet-borne metals; water and sediment standards and criteria; pesticides; amphibians and wildlife toxicology; cyanobacteria; amphibians and wildlife toxicology 2; environmental risk assessment; genomics, protemics, and metabolomics; contamination in the Saguenay-St. Lawrence Marine park; legacy contaminants 3 organics and metals; community level indicators; toxicity tests; toxicity mechanisms; areas of concern; general aquatic toxicology; general legacy contaminants; emerging contaminants; cyanobacteria; amphibians and wildlife toxicology 1; omics in aquatic ecotoxicology; organism or population level indicators; and toxicity tests. The workshop featured 250 presentations, of which 24 have been catalogued separately for inclusion in this database. tabs., figs.

Nanotoxicity: oxidative stress mediated toxicity of metal and metal oxide nanoparticles.

Science.gov (United States)

Sarkar, Abhijit; Ghosh, Manoranjan; Sil, Parames Chandra

2014-01-01

Metal and metal oxide nanoparticles are often used as industrial catalysts or to improve product's functional properties. Recent advanced nanotechnology have been expected to be used in various fields, ranging from sensors, environmental remediation to biomedicine, medical biology and imaging, etc. However, the growing use of nanoparticles has led to their release into environment and increased levels of these particles at nearby sites or the surroundings of their manufacturing factories become obvious. The toxicity of metal and metal oxide nanoparticles on humans, animals, and certainly to the environment has become a major concern to our community. However, controversies still remain with respect to the toxic effects and the mechanisms of these nanoparticles. The scientific community now feels that an understanding of the toxic effects is necessary to handle these nanoparticles and their use. A new discipline, named nanotoxicology, has therefore been developed that basically refers to the study of the interactions of nanoparticles with biological systems and also measures the toxicity level related to human health. Nanoparticles usually generate reactive oxygen species to a greater extent than micro-sized particles resulting in increased pro-inflammatory reactions and oxidative stress via intracellular signaling pathways. In this review, we mainly focus on the routes of exposure of some metal and metal oxide nanoparticles and how these nanoparticles affect us or broadly the cells of our organs. We would also like to discuss the responsible mechanism(s) of the nanoparticle-induced reactive oxygen species mediated organ pathophysiology. A brief introduction of the characterization and application of these nanoparticles has also been included in the article.

1998 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III

International Nuclear Information System (INIS)

Stockton, Marjorie B.

1999-01-01

The Emergency Planning and Community Right-to-Know Act (EPCRA) of 1986 [also known as the Superfund Amendment and Reauthorization Act (SARA), Title III], as modified by Executive Order 12856, requires that all federal facilities evaluate the need to submit an annual Toxic Chemical Release Inventory report as prescribed in Title III, Section 313 of this Act. This annual report is due every July for the preceding calendar year. Owners and operators who manufacture, process, or otherwise use certain toxic chemicals above listed threshold quantities are required to report their toxic chemical releases to all environmental mediums (air, water, soil, etc.). At Los Alamos National Laboratory (LANL), no EPCRA Section 313 chemicals were used in 1998 above the reportable threshold limits of 10,000 lb or 25,000 lb. Therefore LANL was not required to submit any Toxic Chemical Release Inventory reports (Form Rs) for 1998. This document was prepared to provide a detailed description of the evaluation on chemical usage and EPCRA Section 313 threshold determinations for LANL for 1998

Ecological risk assessment in a large river-reservoir. 2: Fish community

International Nuclear Information System (INIS)

Suter, G.W. II; Barnthouse, L.W.; Efroymson, R.A.; Jager, H.

1999-01-01

This paper summarizes the assessment of risks to fishes in the Clinch River Operable Unit due to contaminants released by the US Department of Energy's activities on its Oak Ridge Reservation in Tennessee. This paper focuses on the most contaminated area, the Poplar Creek (PC) embayment. The assessment is of interest because of its use of five distinct lines of evidence: fish community surveys, fish body burdens, toxicity tests of ambient waters, suborganismal bioindicators, and single chemical toxicity tests. None of these lines of evidence provided unambiguous evidence of a significant risk, but the surveys indicated that the fish community in PC was depauperate, polychlorinated biphenyl body burdens may have been at toxic levels in catfish, one of the three tests of ambient water showed clear toxicity, some of the indicators were indicative of toxic effects, and concentrations that have been toxic in the laboratory were detected periodically. Interpretation was further complicated by upstream contamination of both the Clinch River and PC. The risk characterization was performed by evaluating each line of evidence separately and then weighing the evidence using an ecoepidemiological approach

An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

Science.gov (United States)

Somasekharan, Syam Prakash; El-Naggar, Amal; Sorensen, Poul H.

2016-01-01

Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension) than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted. PMID:27656243

An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

Directory of Open Access Journals (Sweden)

Syam Prakash Somasekharan

2016-01-01

Full Text Available Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted.

Ecological effects of various toxic agents on the aquatic microcosm in comparison with acute ionizing radiation

International Nuclear Information System (INIS)

Fuma, S.; Ishii, N.; Takeda, H.; Miyamoto, K.; Yanagisawa, K.; Ichimasa, Y.; Saito, M.; Kawabata, Z.; Polikarpov, G.G.

2003-01-01

The purpose of this study was an evaluation of the effect levels of various toxic agents compared with acute doses of ionizing radiation for the experimental model ecosystem, i.e., microcosm mimicking aquatic microbial communities. For this purpose, the authors used the microcosm consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Escherichia coli as a decomposer. Effects of aluminum and copper on the microcosm were investigated in this study, while effects of γ-rays, ultraviolet radiation, acidification, manganese, nickel and gadolinium were reported in previous studies. The microcosm could detect not only the direct effects of these agents but also the community-level effects due to the interspecies interactions or the interactions between organisms and toxic agents. The authors evaluated doses or concentrations of each toxic agent which had the following effects on the microcosm: (1) no effects; (2) recognizable effects, i.e., decrease or increase in the cell densities of at least one species; (3) severe effects, i.e., extinction of one or two species; and (4) destructive effects, i.e., extinction of all species. The resulting effects data will contribute to an ecological risk assessment of the toxic agents compared with acute doses of ionizing radiation

Diversity of Dominant Bacterial Taxa in Activated Sludge Promotes Functional Resistance following Toxic Shock Loading

KAUST Repository

Saikaly, Pascal

2010-12-14

Examining the relationship between biodiversity and functional stability (resistance and resilience) of activated sludge bacterial communities following disturbance is an important first step towards developing strategies for the design of robust biological wastewater treatment systems. This study investigates the relationship between functional resistance and biodiversity of dominant bacterial taxa by subjecting activated sludge samples, with different levels of biodiversity, to toxic shock loading with cupric sulfate (Cu[II]), 3,5-dichlorophenol (3,5-DCP), or 4-nitrophenol (4-NP). Respirometric batch experiments were performed to determine the functional resistance of activated sludge bacterial community to the three toxicants. Functional resistance was estimated as the 30 min IC50 or the concentration of toxicant that results in a 50% reduction in oxygen utilization rate compared to a referential state represented by a control receiving no toxicant. Biodiversity of dominant bacterial taxa was assessed using polymerase chain reaction-terminal restriction fragment length polymorphism (PCR-T-RFLP) targeting the 16S ribosomal RNA (16S rRNA) gene. Statistical analysis of 30 min IC50 values and PCR-T-RFLP data showed a significant positive correlation (P<0.05) between functional resistance and microbial diversity for each of the three toxicants tested. To our knowledge, this is the first study showing a positive correlation between biodiversity of dominant bacterial taxa in activated sludge and functional resistance. In this system, activated sludge bacterial communities with higher biodiversity are functionally more resistant to disturbance caused by toxic shock loading. © 2010 Springer Science+Business Media, LLC.

Impact of chirano gold mines operations on levels of As, Pb, Hg and Cd in the suraw river and the possible health implications on downstream communities

International Nuclear Information System (INIS)

Oppong, Kyekyeku

2011-07-01

Suraw River water quality awareness and preference survey conducted in five immediate downstream communities indicated that the residents were very much aware of the changes that have occurred since the commencement of active mining by CGML last quarter in 2004. Notwithstanding the residents overwhelming preference for the borehole water for their basic water needs including drinking, some people still rely on the River water when they go to their farms. Suraw River which principally drains the surface waters of Chirano Gold Mines operational area was investigated to assess the levels of As, Cd, Pb and Hg in the River water, bottom sediments and community borehole water using Atomic Absorption Spectrophotometer and Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP – OES) for the water and sediments respectively. The results of the study generally showed low to below laboratory detection levels for the four heavy metals under investigation. The occurrence of Arsenic in more than half of the sampling sites in both the Suraw River and the community boreholes and particularly its detection at S1 in the surface water samples are most probably as a result of natural background levels. Except Cadmium which exceeded the Lowest Effect Level (LEL) in the sediment samples, the concentration of As, Pb and Hg were below the LEL of toxicity. The concentration of Cd also exceeded the Threshold Effect and the Probable Effect Levels but lower than the Severe Effect Level of sediment toxicity at five of the six sampling sites. The study has shown that the concentration of the four heavy metals investigated in both the Suraw River and the community borehole water were lower than expected compared with WHO/GWCL Drinking Water Standards and were within acceptable limits for potable water and therefore do not pose any immediate health risk to residents and settler farmers who still depend on the River water for their basic water needs. Apart from the concentration of Cd

Modeling bubble dynamics and radical kinetics in ultrasound induced microalgal cell disruption.

Science.gov (United States)

Wang, Meng; Yuan, Wenqiao

2016-01-01

Microalgal cell disruption induced by acoustic cavitation was simulated through solving the bubble dynamics in an acoustical field and their radial kinetics (chemical kinetics of radical species) occurring in the bubble during its oscillation, as well as calculating the bubble wall pressure at the collapse point. Modeling results indicated that increasing ultrasonic intensity led to a substantial increase in the number of bubbles formed during acoustic cavitation, however, the pressure generated when the bubbles collapsed decreased. Therefore, cumulative collapse pressure (CCP) of bubbles was used to quantify acoustic disruption of a freshwater alga, Scenedesmus dimorphus, and a marine alga, Nannochloropsis oculata and compare with experimental results. The strong correlations between CCP and the intracellular lipid fluorescence density, chlorophyll-a fluorescence density, and cell particle/debris concentration were found, which suggests that the developed models could accurately predict acoustic cell disruption, and can be utilized in the scale up and optimization of the process. Copyright © 2015 Elsevier B.V. All rights reserved.

PO43- dependence of the tolerance of autotrophic and heterotrophic biofilm communities to copper and diuron.

Science.gov (United States)

Tlili, Ahmed; Bérard, Annette; Roulier, Jean-Louis; Volat, Bernadette; Montuelle, Bernard

2010-06-10

Pollution-induced community tolerance (PICT) concept is based on the assumption that the toxicant exerts selection pressure on the biological communities when exposure reaches a critical level for a sufficient period of time and therefore sensitive species are eliminated. However, induced tolerance of microbial biofilm communities cannot be attributed solely to the presence of toxicants in rivers but also to various environmental factors, such as amount of nutrients. An experimental study was undertaken to highlight the potential impact of a phosphorus gradient on the sensitivity of periphytic microbial community to Cu and diuron. Biofilms were exposed to real-world levels of chronic environmental contamination of toxicants with a phosphorus gradient. Biofilm sensitivity to Cu and diuron was assessed by performing short-term inhibition tests based on photosynthetic efficiency to target photoautotrophs, extracellular enzyme activity (beta-glucosidase and leucine-aminopeptidase) and substrate-induced respiration activity to target heterotrophs. The impact of P-gradient associated to pollution was evaluated by measuring pesticide concentrations in biofilms, biomass parameters (chla, AFDW), bacterial cell density, photosynthetic efficiency and community structure (using 18S and 16S rDNA gene analysis to target eukaryotes and DGGE and HPLC pigment analysis to target bacteria and photoautotrophs). The obtained results show that depending on the studied toxicant and the used structural or functional parameter, the effect of the phosphorus gradient was variable. This highlights the importance of using a range of parameters that target all the biological communities in the biofilm. The PICT method can be regarded as a good tool for assessing anthropogenic environmental contamination, but it is necessary to dissociate the real impact of toxicants from environmental factors.

Individual- and community-level determinants of Inuit youth mental wellness.

Science.gov (United States)

Gray, Andrew Paul; Richer, Faisca; Harper, Sam

2016-10-20

Following the onset of intensive colonial intervention and rapid social change in the lives of Inuit people, youth in Nunavik have experienced high rates of mental health problems and suicide. Inuit people describe a broad range of contextual influences on mental wellness based on lived experience, but most epidemiological studies have focused on individual risk factors and pathologies. This study aimed to assess the influence of multiple determinants of mental wellness among Inuit youth in Nunavik, including culturally meaningful activities, housing and community social characteristics. Mental wellness was measured in the form of two primary outcomes: self-esteem and suicidal ideation. Using cross-sectional data from the 2004 Nunavik Inuit Health Survey and multilevel regression modelling, we estimated associations between these two outcomes and various independent individual- and community-level explanatory factors among Inuit youth. All variables were selected to reflect Inuit perspectives on determinants of mental wellness. The study design and interpretation of results were validated with Inuit community representatives. Pride in Inuit identity, traditional activities, community-level social support and community-level socio-economic status were found to be protective. Barriers to participating in traditional activities, household crowding and high community rates of violence were risk factors. These findings support Inuit perspectives, expand the scope of epidemiological analysis of Inuit mental wellness and reinforce the need for locally informed, community-wide approaches to mental wellness promotion for Inuit youth.

Tolerance and toxicity levels of boron in mung bean (vigna radiata (l.) wilczek) cultivars at early growth stages

International Nuclear Information System (INIS)

Hasnain, A.; Mahmood, S.; Akhtar, S.; Malik, S.A.; Bashir, N.

2011-01-01

Boron (B) toxicity has been recognized as a serious problem in arid and semi arid regions of the world. This study was aimed to determine critical levels of B by studying phenotypic variation for B-tolerance/ toxicity at the germination and seedling stage in three mung bean (Vigna radiata) cultivars; M-6, M-8 and 96009. Boron levels ranging from 0-20 ppm were applied using Boric acid. Germination, growth and photosynthetic attributes were significantly (p<0.001) influenced by varying B levels. However, the cultivars were significantly invariable for germination, seedling height and leaf number. B levels (5-10 ppm) appeared to be nutritionally critical whereas, 15-20 ppm induced B toxicity. The toxicity was expressed in terms of reduction in plant's growth as well as by visible symptoms which included chlorosis and necrosis of the foliage. The present study also demonstrated variation in B tolerance at the seedling stage in these cultivars. Among the tested cultivars, M-6 and M-8 exhibited better growth responses as compared with 96009. Fresh biomass and shoot: root ratio appeared to serve as selection criteria for B tolerance. The study further suggested screening of cultivars/ accessions on a large scale to explore more diversity of traits as well as the use of biochemical markers for mechanistic understanding of B tolerance. (author)

Chemicals to enhance microalgal growth and accumulation of high-value bioproducts

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Xinheng eYu

2015-02-01

Full Text Available Photosynthetic microalgae have attracted significant attention as they can serve as important sources for cosmetic, food and pharmaceutical products, industrial materials and even biofuel biodiesels. However, current productivity of microalga-based processes is still very low, which has restricted their scale-up application. In addition to various efforts in strain improvement and cultivation optimization, it was proposed that the productivity of microalga-based processes can also be increased using various chemicals to trigger or enhance cell growth and accumulation of bioproducts. Herein, we summarized recent progresses in applying chemical triggers or enhancers to improve cell growth and accumulation of bioproducts in algal cultures. Based on their enhancing mechanisms, these chemicals can be classified into four categories：chemicals regulating biosynthetic pathways, chemicals inducing oxidative stress responses, phytohormones and analogues regulating multiple aspects of microalgal metabolism, and chemicals directly as metabolic precursors. Taken together, the early researches demonstrated that the use of chemical stimulants could be a very effective and economical way to improve cell growth and accumulation of high-value bioproducts in large-scale cultivation of microalgae.

Evaluation of single and joint toxic effects of diuron and its main metabolites on natural phototrophic biofilms using a pollution-induced community tolerance (PICT) approach.

Science.gov (United States)

Pesce, Stéphane; Lissalde, Sophie; Lavieille, Delphine; Margoum, Christelle; Mazzella, Nicolas; Roubeix, Vincent; Montuelle, Bernard

2010-09-15

This study assessed the single and joint acute toxicity of diuron and two of its metabolites (DCPMU and 3,4-DCA) on natural phototrophic biofilms using a PICT approach with photosynthesis bioassays. River biofilm communities were collected at three sampling stations exhibiting increasing concentrations of diuron, DCPMU and 3,4-DCA from upstream to downstream. Applied individually, the parent compound was more toxic than its metabolites, with DCPMU being more toxic than 3,4-DCA which only inhibited photosynthesis at very high concentrations (EC25 at about 5 mg/l). Sensitivity of biofilm communities to diuron and DCPMU decreased from upstream to downstream, revealing tolerance induction in contaminated sections of the river, as expected from the PICT concept. Nevertheless, PICT was not applicable for 3,4-DCA, which similarly affected upstream, intermediate and downstream biofilm communities. Chemical mixtures of diuron and DCPMU demonstrated additive effects whereas combinations with 3,4-DCA enhanced the observed effects. Our results reveal that the individual and combined presence of diuron and DCPMU in lotic ecosystems can have both short-term effects (as shown with bioassays) and long-term effects (as shown through the PICT approach) on phototrophic biofilms, whereas environmental concentrations of 3,4-DCA may not affect biofilm photosynthetic activity. 2010 Elsevier B.V. All rights reserved.

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

International Nuclear Information System (INIS)

Geurts, Jeroen J.M.; Sarneel, Judith M.; Willers, Bart J.C.; Roelofs, Jan G.M.; Verhoeven, Jos T.A.; Lamers, Leon P.M.

2009-01-01

Both eutrophication and SO 4 pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO 4 were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO 4 addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO 4 pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO 4 pollution, sulphide toxicity and nutrient availability.

Novel Concept for LSS Based on Advanced Microalgal Biotechnologies

Science.gov (United States)

Brown, I.; Jones, J. A.; Bayless, D.; Karakis, S.; Karpov, L.; McKay, D. S.

2006-01-01

One of the key issues for successful human space exploration is biomedical life support in hostile space and planetary environments that otherwise cannot sustain life. Bioregenerative life support systems (LSS) are one of the options for atmospheric regeneration. To date, no bioregenerative LSS has shown capability for 100% air regeneration. Nor have these LSS been robust enough to simultaneously provide a regenerable complete food source. In contrast to microalgae, traditional plant approaches, e.g. wheat and lettuce, are lacking essential amino acids, vitamins, and micronutrients. Moreover, the rate of photosynthesis by microalgae significantly exceeds that of high plants. Nevertheless, the employment of microalgae in LSS technology was restricted, until recently, due to high water demands. Also the per person requirement of a 40L volume of microalgae in a photobioreactor, to provide daily O2 production, made an algae-based approach less attractive. By employing a vertically stacked membrane bioreactor, coupled with a solar tracker and photon-delivery system, a lightweight air revitalization system for space based applications, with minimal water requirements, can be developed. Our preliminary estimations suggest that a membrane bioreactor, 8m3 in volume, comprised of 80m2 (twenty 2m x 2m membranes, each spaced 10 cm apart), and a total of 70L of water could produce 2.7 kg of dried microalgal biomass that would supply the energy and essential amino acid requirements, as well as producing sufficient O2 for the daily needs of a 15 member crew. Research on the biochemical content of edible blue-green alga Spirulina (Arthrospira) platensis shows a wide spectrum of stable Spirulina mutants with an enhanced content of amino acids, -carotene, and phycobilliprotein c-phycocyanin. Feeding animals suffering from radiation-induced lesions, c-phycocyanin, extracted from strain 27G, led to a correction in the decrement of dehydrogenase activity and energy-rich phosphate

New Jersey: Clean Air Communities (A Former EPA CARE Project)

Science.gov (United States)

Clean Air Communities (CAC) is the recipient of a Level II CARE cooperative agreement to implement recommendations by the state’s Environmental Justice Task Force and the Air Toxics Pilot Project to reduce environmental risks.

Cascading effects of mass mortality events in Arctic marine communities.

Science.gov (United States)

Langangen, Øystein; Ohlberger, Jan; Stige, Leif C; Durant, Joël M; Ravagnan, Elisa; Stenseth, Nils C; Hjermann, Dag Ø

2017-01-01

Mass mortality events caused by pulse anthropogenic or environmental perturbations (e.g., extreme weather, toxic spills or epizootics) severely reduce the abundance of a population in a short time. The frequency and impact of these events are likely to increase across the globe. Studies on how such events may affect ecological communities of interacting species are scarce. By combining a multispecies Gompertz model with a Bayesian state-space framework, we quantify community-level effects of a mass mortality event in a single species. We present a case study on a community of fish and zooplankton in the Barents Sea to illustrate how a mass mortality event of different intensities affecting the lower trophic level (krill) may propagate to higher trophic levels (capelin and cod). This approach is especially valuable for assessing community-level effects of potential anthropogenic-driven mass mortality events, owing to the ability to account for uncertainty in the assessed impact due to uncertainty about the ecological dynamics. We hence quantify how the assessed impact of a mass mortality event depends on the degree of precaution considered. We suggest that this approach can be useful for assessing the possible detrimental outcomes of toxic spills, for example oil spills, in relatively simple communities such as often found in the Arctic, a region under increasing influence of human activities due to increased land and sea use. © 2016 John Wiley & Sons Ltd.

Processed fruit juice ready to drink: screening acute toxicity at the cellular level

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Erick Leal da Silva

2017-06-01

Full Text Available The present study evaluated the acute toxicity at the cellular level of processed juice ready for consumption Orange and Grape flavors, produced by five companies with significant influence on the food market of South American countries, especially in Brazil. This evaluation was performed in root meristem cells of Allium cepa L., at the exposure times of 24 and 48 hours, directly with marketed liquid preparations. Based on the results, it was found that fruit juices, of all companies considered, promoted significant antiproliferative effect to root meristems at the exposure time of 24 hours and resulted in at both exposure times, statistically significant number of mitotic spindle changes and chromosomal breaks. Therefore, under the study conditions, all juice samples analyzed were cytotoxic, genotoxic and mutagenic to root meristem cells. These results indicate that such beverages have relevant potential to cause cellular disorders and, thus, need to be evaluated more fully in more complex test systems, as those in rodents, and then establish specific toxicity at the cellular level of these juices and ensure the well-being of those who consume them.

Risk factors associated with the blood lead levels of children in the Community of Madrid in 2010

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José María Ordóñez-Iriarte

2013-12-01

Full Text Available Introduction: Lead is a toxic element for humans, with children being the most vulnerable population.Objective: To find out the risk factors associated to the existing blood lead levels (BLLs of children in the Community of Madrid, after 9 years of lead being banned in gasoline.Methods: A cross-sectional study was carried out in 2010 with a sample of 85 children, less than 15 years of age, recruited via the outpatients’ service of the Pediatrics Department of the Hospital Clínico San Carlos in Madrid. Routine blood tests provided the opportunity for determining other blood parameters. Lead levels were measured using electrothermal-atomization atomic absorption spectrometry with the Zeeman-effect background correction. In addition, a survey was undertaken directed to the parents for gathering information about a series of socioeconomic and environmental variables.Results: The arithmetic mean of the BLLs in the children was 1.1 μg/dL (SD=0.7 μg/dL with a range from 0.1 μg/dL to 3.4 μg/dL. The geometric mean was 0.9 μg/dL (SD= 1.1 μg/dL. The risk factors associated to these BLLs are the following: playing in the street; low educational level of the parents; leisure activities of one of the parents linked to lead; tobacco smoking of the father; and drinking tap water.Conclusions: The BLLs of the children in the Community of Madrid have decreased, but there are still sociodemographic and environmental risk factors associated to the present levels.

Physical activity level and fall risk among community-dwelling older adults.

Science.gov (United States)

Low, Sok Teng; Balaraman, Thirumalaya

2017-07-01

[Purpose] To find the physical activity level and fall risk among the community-dwelling Malaysian older adults and determine the correlation between them. [Subjects and Methods] A cross-sectional study was conducted in which, the physical activity level was evaluated using the Rapid Assessment of Physical Activity questionnaire and fall risk with Fall Risk Assessment Tool. Subjects recruited were 132 community-dwelling Malaysian older adults using the convenience sampling method. [Results] The majority of the participants were under the category of under-active regular light-activities and most of them reported low fall risk. The statistical analysis using Fisher's exact test did not show a significant correlation between physical activity level and fall risk. [Conclusion] The majority of community-dwelling Malaysian older adults are performing some form of physical activity and in low fall risk category. But this study did not find any significant correlation between physical activity level and fall risk among community-dwelling older adults in Malaysia.

Community-based population-level interventions for promoting child oral health.

OpenAIRE

de Silva, AM; Hegde, S; Akudo Nwagbara, B; Calache, H; Gussy, MG; Nasser, M; Morrice, HR; Riggs, E; Leong, PM; Meyenn, LK; Yousefi-Nooraie, R

2016-01-01

BACKGROUND: Dental caries and gingival and periodontal disease are commonly occurring, preventable chronic conditions. Even though much is known about how to treat oral disease, currently we do not know which community-based population-level interventions are most effective and equitable in preventing poor oral health. OBJECTIVES: Primary • To determine the effectiveness of community-based population-level oral health promotion interventions in preventing dental caries and gingival and period...

Microalgal Metabolic Network Model Refinement through High-Throughput Functional Metabolic Profiling

International Nuclear Information System (INIS)

Chaiboonchoe, Amphun; Dohai, Bushra Saeed; Cai, Hong; Nelson, David R.; Jijakli, Kenan; Salehi-Ashtiani, Kourosh

2014-01-01

Metabolic modeling provides the means to define metabolic processes at a systems level; however, genome-scale metabolic models often remain incomplete in their description of metabolic networks and may include reactions that are experimentally unverified. This shortcoming is exacerbated in reconstructed models of newly isolated algal species, as there may be little to no biochemical evidence available for the metabolism of such isolates. The phenotype microarray (PM) technology (Biolog, Hayward, CA, USA) provides an efficient, high-throughput method to functionally define cellular metabolic activities in response to a large array of entry metabolites. The platform can experimentally verify many of the unverified reactions in a network model as well as identify missing or new reactions in the reconstructed metabolic model. The PM technology has been used for metabolic phenotyping of non-photosynthetic bacteria and fungi, but it has not been reported for the phenotyping of microalgae. Here, we introduce the use of PM assays in a systematic way to the study of microalgae, applying it specifically to the green microalgal model species Chlamydomonas reinhardtii. The results obtained in this study validate a number of existing annotated metabolic reactions and identify a number of novel and unexpected metabolites. The obtained information was used to expand and refine the existing COBRA-based C. reinhardtii metabolic network model iRC1080. Over 254 reactions were added to the network, and the effects of these additions on flux distribution within the network are described. The novel reactions include the support of metabolism by a number of d-amino acids, l-dipeptides, and l-tripeptides as nitrogen sources, as well as support of cellular respiration by cysteamine-S-phosphate as a phosphorus source. The protocol developed here can be used as a foundation to functionally profile other microalgae such as known microalgae mutants and novel isolates.

Microalgal Metabolic Network Model Refinement through High-Throughput Functional Metabolic Profiling

Energy Technology Data Exchange (ETDEWEB)

Chaiboonchoe, Amphun; Dohai, Bushra Saeed; Cai, Hong; Nelson, David R. [Division of Science and Math, New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi Institute, Abu Dhabi (United Arab Emirates); Jijakli, Kenan [Division of Science and Math, New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi Institute, Abu Dhabi (United Arab Emirates); Engineering Division, Biofinery, Manhattan, KS (United States); Salehi-Ashtiani, Kourosh, E-mail: ksa3@nyu.edu [Division of Science and Math, New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi Institute, Abu Dhabi (United Arab Emirates)

2014-12-10

Metabolic modeling provides the means to define metabolic processes at a systems level; however, genome-scale metabolic models often remain incomplete in their description of metabolic networks and may include reactions that are experimentally unverified. This shortcoming is exacerbated in reconstructed models of newly isolated algal species, as there may be little to no biochemical evidence available for the metabolism of such isolates. The phenotype microarray (PM) technology (Biolog, Hayward, CA, USA) provides an efficient, high-throughput method to functionally define cellular metabolic activities in response to a large array of entry metabolites. The platform can experimentally verify many of the unverified reactions in a network model as well as identify missing or new reactions in the reconstructed metabolic model. The PM technology has been used for metabolic phenotyping of non-photosynthetic bacteria and fungi, but it has not been reported for the phenotyping of microalgae. Here, we introduce the use of PM assays in a systematic way to the study of microalgae, applying it specifically to the green microalgal model species Chlamydomonas reinhardtii. The results obtained in this study validate a number of existing annotated metabolic reactions and identify a number of novel and unexpected metabolites. The obtained information was used to expand and refine the existing COBRA-based C. reinhardtii metabolic network model iRC1080. Over 254 reactions were added to the network, and the effects of these additions on flux distribution within the network are described. The novel reactions include the support of metabolism by a number of d-amino acids, l-dipeptides, and l-tripeptides as nitrogen sources, as well as support of cellular respiration by cysteamine-S-phosphate as a phosphorus source. The protocol developed here can be used as a foundation to functionally profile other microalgae such as known microalgae mutants and novel isolates.

The Domestic Violence Fatality Review: Can It Mobilize Community-Level Change?

Science.gov (United States)

Storer, Heather L.; Lindhorst, Taryn; Starr, Kelly

2015-01-01

Domestic Violence Fatality Review (DVFR) teams are a means of identifying systems’ gaps in the coordinated response to domestic violence. While the number of homicide reviews has grown, little is known about whether DVFRs facilitate change in the community-level response to domestic violence. This research evaluated whether the recommendations made by one state-level DVFR had an effect on community and organizational priorities and practices. The results indicate that the recommendations influence countywide priorities, but less was done to implement the recommendations. DVFRs have the capacity to influence community-level change agendas; however, organizations need support moving from issue prioritization to implementation. PMID:25741174

Mining Community-Level Influence in Microblogging Network: A Case Study on Sina Weibo

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Yufei Liu

2017-01-01

Full Text Available Social influence analysis is important for many social network applications, including recommendation and cybersecurity analysis. We observe that the influence of community including multiple users outweighs the individual influence. Existing models focus on the individual influence analysis, but few studies estimate the community influence that is ubiquitous in online social network. A major challenge lies in that researchers need to take into account many factors, such as user influence, social trust, and user relationship, to model community-level influence. In this paper, aiming to assess the community-level influence effectively and accurately, we formulate the problem of modeling community influence and construct a community-level influence analysis model. It first eliminates the zombie fans and then calculates the user influence. Next, it calculates the user final influence by combining the user influence and the willingness of diffusing theme information. Finally, it evaluates the community influence by comprehensively studying the user final influence, social trust, and relationship tightness between intrausers of communities. To handle real-world applications, we propose a community-level influence analysis algorithm called CIAA. Empirical studies on a real-world dataset from Sina Weibo demonstrate the superiority of the proposed model.

Toxic chemical release inventory reporting form R and instructions. Revised 1992 version. Section 313 of the Emergency Planning and Community Right-to-Know Act

International Nuclear Information System (INIS)

1993-01-01

Reporting is required to provide the public with information on the releases of listed toxic chemicals in their communities and to provide EPA with release information to assist the Agency in determining the need for future regulations. Facilities must report the quantities of both routine and accidental releases of listed toxic chemicals, as well as the maximum amount of the listed toxic chemical on-site during the calendar year and the amount contained in wastes transferred off-site. These instructions supplement and elaborate on the requirements in the reporting rule (40 CFR Part 372). Together with the reporting rule, they constitute the reporting requirements. All references in these instructions are to sections in the reporting rule unless otherwise indicated

Association between individual-level and community-level socio-economic status and blood pressure among Inuit in Greenland

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Mylène Riva

2016-12-01

Full Text Available Background: Despite abundant evidence that socio-economic status (SES is a fundamental determinant of health, there is a dearth of research examining association between SES, measured at the individual and community levels, and cardiovascular risk factors and morbidity among indigenous populations. Objectives: To examine the influence of individual-level and community-level SES on systolic and diastolic blood pressure among Greenlandic Inuit. Methods: Multilevel analysis of cross-sectional data from the Inuit Health in Transition – Greenland Survey, to which 3,108 Greenlandic Inuit aged 18 years and older participated. Blood pressure is measured using an automatic device, according to standardized protocol. Individual SES is measured by education. Community socio-economic conditions are measured using combined information on average disposable household income and settlement type. Results: Education was not significantly associated with blood pressure. There was an inverse U-shape association between community socio-economic conditions and blood pressure with significantly lower SBP and DBP among participants living in remote traditional villages characterized by lower average disposable household income and in affluent more urbanized towns. Sex-stratified analyses demonstrate the salience of community conditions for men. Conclusions: The association observed between blood pressure and community-level socio-economic conditions suggests that public health and social policies, programmes and interventions aiming to improve living conditions might improve cardiovascular health in Greenland. Studies are required to further examine social gradients in cardiovascular risk factors and morbidity among indigenous populations using different measures of SES.

Association between individual-level and community-level socio-economic status and blood pressure among Inuit in Greenland.

Science.gov (United States)

Riva, Mylène; Larsen, Christina Viskum Lytken; Bjerregaard, Peter

2016-01-01

Despite abundant evidence that socio-economic status (SES) is a fundamental determinant of health, there is a dearth of research examining association between SES, measured at the individual and community levels, and cardiovascular risk factors and morbidity among indigenous populations. To examine the influence of individual-level and community-level SES on systolic and diastolic blood pressure among Greenlandic Inuit. Multilevel analysis of cross-sectional data from the Inuit Health in Transition - Greenland Survey, to which 3,108 Greenlandic Inuit aged 18 years and older participated. Blood pressure is measured using an automatic device, according to standardized protocol. Individual SES is measured by education. Community socio-economic conditions are measured using combined information on average disposable household income and settlement type. Education was not significantly associated with blood pressure. There was an inverse U-shape association between community socio-economic conditions and blood pressure with significantly lower SBP and DBP among participants living in remote traditional villages characterized by lower average disposable household income and in affluent more urbanized towns. Sex-stratified analyses demonstrate the salience of community conditions for men. The association observed between blood pressure and community-level socio-economic conditions suggests that public health and social policies, programmes and interventions aiming to improve living conditions might improve cardiovascular health in Greenland. Studies are required to further examine social gradients in cardiovascular risk factors and morbidity among indigenous populations using different measures of SES.

Increasing Resilience Through Engagement In Sea Level Rise Community Science Initiatives.

Science.gov (United States)

Chilton, L. A.; Rindge, H.

2017-12-01

Science literate and engaged members of the public, including students, are critical to building climate resilient communities. USC Sea Grant facilitates programs that work to build and strengthen these connections. The Urban Tides Community Science Initiative (Urban Tides) and the Youth Exploring Sea Level Rise Science Program (YESS) engage communities across the boundaries of public engagement, K-12 education, and informal education. YESS is an experiential sea level rise education program that combines classroom learning, field investigations and public presentations. Students explore sea level rise using a new curricula, collect their own data on sea level rise, develop communication products, and present their findings to city governments, researchers, and others. Urban Tides engages community members, informal education centers, K-12 students, and local government leaders in a citizen science program photo- documenting extreme high tides, erosion and coastal flooding in Southern California. Images provide critical information to help calibrate scientific models used to identify locations vulnerable to damage from future sea level rise. These tools and information enable community leaders and local governments to set priorities, guidelines, and update policies as they plan strategies that will help the region adapt. The program includes a mobile app for data collection, an open database to view photos, a lesson plan, and community beach walks. Urban Tides has led to an increase in data and data-gathering capacity for regional scientists, an increase in public participation in science, and an increase in ocean and climate literacy among initiative participants. Both of these programs bring informed and diverse voices into the discussion of how to adapt and build climate resilient communities. USC Sea Grant will share impacts and lessons learned from these two unique programs.

Metabolite Profiling of the Microalgal Diatom Chaetoceros Calcitrans and Correlation with Antioxidant and Nitric Oxide Inhibitory Activities via 1H NMR-Based Metabolomics

Directory of Open Access Journals (Sweden)

Awanis Azizan

2018-05-01

Full Text Available Microalgae are promising candidate resources from marine ecology for health-improving effects. Metabolite profiling of the microalgal diatom, Chaetoceros calcitrans was conducted by using robust metabolomics tools, namely 1H nuclear magnetic resonance (NMR spectroscopy coupled with multivariate data analysis (MVDA. The unsupervised data analysis, using principal component analysis (PCA, resolved the five types of extracts made by solvents ranging from polar to non-polar into five different clusters. Collectively, with various extraction solvents, 11 amino acids, cholesterol, 6 fatty acids, 2 sugars, 1 osmolyte, 6 carotenoids and 2 chlorophyll pigments were identified. The fatty acids and both carotenoid pigments as well as chlorophyll, were observed in the extracts made from medium polar (acetone, chloroform and non-polar (hexane solvents. It is suggested that the compounds were the characteristic markers that influenced the separation between the clusters. Based on partial least square (PLS analysis, fucoxanthin, astaxanthin, violaxanthin, zeaxanthin, canthaxanthin, and lutein displayed strong correlation to 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging and nitric oxide (NO inhibitory activity. This metabolomics study showed that solvent extractions are one of the main bottlenecks for the maximum recovery of bioactive microalgal compounds and could be a better source of natural antioxidants due to a high value of metabolites.

A simple method for decomposition of peracetic acid in a microalgal cultivation system.

Science.gov (United States)

Sung, Min-Gyu; Lee, Hansol; Nam, Kibok; Rexroth, Sascha; Rögner, Matthias; Kwon, Jong-Hee; Yang, Ji-Won

2015-03-01

A cost-efficient process devoid of several washing steps was developed, which is related to direct cultivation following the decomposition of the sterilizer. Peracetic acid (PAA) is known to be an efficient antimicrobial agent due to its high oxidizing potential. Sterilization by 2 mM PAA demands at least 1 h incubation time for an effective disinfection. Direct degradation of PAA was demonstrated by utilizing components in conventional algal medium. Consequently, ferric ion and pH buffer (HEPES) showed a synergetic effect for the decomposition of PAA within 6 h. On the contrary, NaNO3, one of the main components in algal media, inhibits the decomposition of PAA. The improved growth of Chlorella vulgaris and Synechocystis PCC6803 was observed in the prepared BG11 by decomposition of PAA. This process involving sterilization and decomposition of PAA should help cost-efficient management of photobioreactors in a large scale for the production of value-added products and biofuels from microalgal biomass.

Effect of nitrogen regime on microalgal lipid production during mixotrophic growth with glycerol.

Science.gov (United States)

Paranjape, Kiran; Leite, Gustavo B; Hallenbeck, Patrick C

2016-08-01

Mixotrophic growth of microalgae to boost lipid production is currently under active investigation. Such a process could be of practical importance if a cheap source of organic carbon, such as waste glycerol from biodiesel production, could be used. Several previous studies have already demonstrated that this carbon source can be used by different indigenous strains of microalgae. In this study it is shown that different nitrogen limitation strategies can be applied to further increase lipid production during growth with glycerol. In one strategy, cultures were grown in nitrogen replete medium and then resuspended in nitrogen free medium. In a second strategy, cultures were grown with different initial concentrations of nitrate. Lipid production by the two microalgal strains used, Chlorella sorokiniana (PCH02) and Chlorella vulgaris (PCH05), was shown to be boosted by strategies of nitrogen limitation, but they responded differently to how nitrogen limitation was imposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toxic metal levels in children residing in a smelting craft village in Vietnam: a pilot biomonitoring study.

Science.gov (United States)

Sanders, Alison P; Miller, Sloane K; Nguyen, Viet; Kotch, Jonathan B; Fry, Rebecca C

2014-02-04

In Vietnam, environmental pollution caused by small-scale domestic smelting of automobile batteries into lead ingot is a growing concern. The village of Nghia Lo is a smelting craft village located roughly 25 km southeast of Hanoi in the Red River Delta. Despite the concern of toxic metal exposure in the village, biomonitoring among susceptible populations, such as children, has not been previously conducted. The aim of this study was to determine the body burden of toxic metals in children residing in a smelting craft village. Twenty children from Nghia Lo, Vietnam, ages 18 months to four years were selected for capillary whole blood and toenail biomonitoring. Whole blood lead levels (BLLs) were measured using a portable lead analyzer, and toenail levels of arsenic, cadmium, chromium, lead, manganese, and mercury were analyzed with inductively coupled plasma-mass spectrometry. The findings show that all of the 20 children had detectable BLLs, and every child had levels that exceeded the Centers for Disease Control and Prevention guideline level of 5 μg/dL. Eighty percent of tested subjects had BLLs higher than 10 μg/dL. Five children (25%) had BLLs greater than 45 μg/dL, the level of recommended medical intervention. In addition to blood lead, all of the children had detectable levels of arsenic, cadmium, chromium, lead, manganese, and mercury in toenail samples. Notably, average toenail lead, manganese, and mercury levels were 157 μg/g, 7.41 μg/g, and 2.63 μg/g respectively, well above levels previously reported in children. Significant Spearman's rank correlations showed that there were relationships between blood and toenail lead levels (r = 0.65, p craft villages in Vietnam are co-exposed to toxic metals. There is an urgent need for mitigation to control metal exposure related to domestic smelting.

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

Energy Technology Data Exchange (ETDEWEB)

Geurts, Jeroen J.M., E-mail: j.geurts@b-ware.e [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); B-WARE Research Centre, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Sarneel, Judith M. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Willers, Bart J.C.; Roelofs, Jan G.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Verhoeven, Jos T.A. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Lamers, Leon P.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)

2009-07-15

Both eutrophication and SO{sub 4} pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO{sub 4} were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO{sub 4} addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO{sub 4} pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO{sub 4} pollution, sulphide toxicity and nutrient availability.

Concussions in Community-Level Rugby: Risk, Knowledge, and Attitudes.

Science.gov (United States)

Martin, R Kyle; Hrubeniuk, Travis J; Witiw, Christopher D; MacDonald, Peter; Leiter, Jeff

Rugby is a popular collision sport where participants are at risk of sustaining concussions. Most research focuses on elite-level or youth divisions. Comparatively, little is known about adult community rugby. The aim of this research was to estimate the risk of sustaining a concussion during participation in community-level rugby and summarize the collective knowledge and attitudes toward concussions. Concussion symptoms will be reported frequently among community-level rugby players and a substantial proportion will report a willingness to continue participation despite the risk. Cross-sectional analysis. Level 3. An anonymous, voluntary survey was administered to all 464 senior rugby players registered in the province of Manitoba in 2015. Two primary domains were assessed: (1) concussion history from the preceding season including occurrence, symptomatology, and impact on daily activities and (2) knowledge and attitudes toward concussion risks and management. In total, 284 (61.2%) rugby players responded. Concussive symptoms were reported by 106 (37.3%). Of those, 87% were formally diagnosed with a concussion and 27% missed school and/or work as a result. The danger of playing while symptomatic was recognized by 93.7% of participants, yet 29% indicated they would continue while symptomatic. Furthermore, 39% felt they were letting others down if they stopped playing due to a concussion. Concussive symptoms were common among the study cohort and had a notable impact on daily activities. A high proportion of players were willing to continue while experiencing symptoms despite recognizing the danger. The observed discord between knowledge and attitudes implicates a culture of "playing injured." Understanding the risk of injury may affect an individual's decision to participate in community-level rugby. Moreover, evidence of discord between the knowledge and attitudes of players may direct future research initiatives and league governance.

Anaerobic co-digestion of coffee husks and microalgal biomass after thermal hydrolysis.

Science.gov (United States)

Passos, Fabiana; Cordeiro, Paulo Henrique Miranda; Baeta, Bruno Eduardo Lobo; de Aquino, Sergio Francisco; Perez-Elvira, Sara Isabel

2018-04-01

Residual coffee husks after seed processing may be better profited if bioconverted into energy through anaerobic digestion. This process may be improved by implementing a pretreatment step and by co-digesting the coffee husks with a more liquid biomass. In this context, this study aimed at evaluating the anaerobic co-digestion of coffee husks with microalgal biomass. For this, both substrates were pretreated separately and in a mixture for attaining 15% of total solids (TS), which was demonstrated to be the minimum solid content for pretreatment of coffee husks. The results showed that the anaerobic co-digestion presented a synergistic effect, leading to 17% higher methane yield compared to the theoretical value of both substrates biodegraded separately. Furthermore, thermal hydrolysis pretreatment increased coffee husks anaerobic biodegradability. For co-digestion trials, the highest values were reached for pretreatment at 120 °C for 60 min, which led to 196 mLCH 4 /gVS and maximum methane production rate of 0.38 d -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Composition and Quantitation of Microalgal Lipids by ERETIC 1H NMR Method

Directory of Open Access Journals (Sweden)

Angelo Fontana

2013-09-01

Full Text Available Accurate characterization of biomass constituents is a crucial aspect of research in the biotechnological application of natural products. Here we report an efficient, fast and reproducible method for the identification and quantitation of fatty acids and complex lipids (triacylglycerols, glycolipids, phospholipids in microalgae under investigation for the development of functional health products (probiotics, food ingredients, drugs, etc. or third generation biofuels. The procedure consists of extraction of the biological matrix by modified Folch method and direct analysis of the resulting material by proton nuclear magnetic resonance (1H NMR. The protocol uses a reference electronic signal as external standard (ERETIC method and allows assessment of total lipid content, saturation degree and class distribution in both high throughput screening of algal collection and metabolic analysis during genetic or culturing studies. As proof of concept, the methodology was applied to the analysis of three microalgal species (Thalassiosira weissflogii, Cyclotella cryptica and Nannochloropsis salina which drastically differ for the qualitative and quantitative composition of their fatty acid-based lipids.

Does Social Capital Explain Community-Level Differences in Organ Donor Designation?

Science.gov (United States)

Ladin, Keren; Wang, Rui; Fleishman, Aaron; Boger, Matthew; Rodrigue, James R

2015-09-01

The growing shortage of life-saving organs has reached unprecedented levels, with more than 120,000 Americans waiting for them. Despite national attempts to increase organ donation and federal laws mandating the equitable allocation of organs, geographic disparities remain. A better understanding of the contextual determinants of organ donor designation, including social capital, may enhance efforts to increase organ donation by raising the probability of collective action and fostering norms of reciprocity and cooperation while increasing costs to defectors. Because community-level factors, including social capital, predict more than half the variation in donor designation, future interventions should tailor strategies to specific communities as the unit of intervention. The growing shortage of organs has reached unprecedented levels. Despite national attempts to increase donation and federal laws mandating the equitable allocation of organs, their availability and waiting times vary significantly nationwide. Organ donor designation is a collective action problem in public health, in which the regional organ supply and average waiting times are determined by the willingness of individuals to be listed as organ donors. Social capital increases the probability of collective action by fostering norms of reciprocity and cooperation while increasing costs to defectors. We examine whether social capital and other community-level factors explain geographic variation in organ donor designation rates in Massachusetts. We obtained a sample of 3,281,532 registered drivers in 2010 from the Massachusetts Department of Transportation Registry of Motor Vehicles (MassDOT RMV). We then geocoded the registry data, matched them to 4,466 census blocks, and linked them to the 2010 US Census, the American Community Survey (ACS), and other sources to obtain community-level sociodemographic, social capital (residential segregation, voter registration and participation, residential

Mapping the extent and relative toxicity of sediments, Winter Quarters Bay, Antarctica

International Nuclear Information System (INIS)

Crockett, A.; White, G.; Huynh, H.

1995-01-01

McMurdo Station was established in the mid 1950s and is the largest research station in Antarctica. In earlier days, wastes were dumped on the steep shores of Winter Quarters Bay, dosed with up to 19,000 L of diesel or jet fuel and ignited. Along with periodic fuel spills, and the discharge of raw sewage the Bay became littered with trash and contaminated with elevated levels of metals, PCBs and petroleum hydrocarbons. The original benthic community was essentially totally replaced with more opportunistic species. In 1993, a study was initiated to map the distribution of PCB and hydrocarbon contamination as well as determine sediment pore water toxicity. Sediments were collected from over forty locations with an Ekman dredge after drilling through about 210 cm of ice. Maps of sediment particle size distribution, percent organic carbon, total PCBs, total petroleum hydrocarbons, etc. were developed. Potential toxicity was mapped by normalizing the data to 1 percent organic carbon and comparing the data with various sediment quality criteria. While onsite sediment pore water toxicity tests showed essentially no impacts, the new Microtox trademark chronic bioassay on both pore water and solvent extra showed considerable toxic effects. This paper compares the relative levels of contamination, with sediment quality criteria and toxicity as determined by a chronic microbial bioassays

Prediction of human population responses to toxic compounds by a collaborative competition.

Science.gov (United States)

Eduati, Federica; Mangravite, Lara M; Wang, Tao; Tang, Hao; Bare, J Christopher; Huang, Ruili; Norman, Thea; Kellen, Mike; Menden, Michael P; Yang, Jichen; Zhan, Xiaowei; Zhong, Rui; Xiao, Guanghua; Xia, Menghang; Abdo, Nour; Kosyk, Oksana; Friend, Stephen; Dearry, Allen; Simeonov, Anton; Tice, Raymond R; Rusyn, Ivan; Wright, Fred A; Stolovitzky, Gustavo; Xie, Yang; Saez-Rodriguez, Julio

2015-09-01

The ability to computationally predict the effects of toxic compounds on humans could help address the deficiencies of current chemical safety testing. Here, we report the results from a community-based DREAM challenge to predict toxicities of environmental compounds with potential adverse health effects for human populations. We measured the cytotoxicity of 156 compounds in 884 lymphoblastoid cell lines for which genotype and transcriptional data are available as part of the Tox21 1000 Genomes Project. The challenge participants developed algorithms to predict interindividual variability of toxic response from genomic profiles and population-level cytotoxicity data from structural attributes of the compounds. 179 submitted predictions were evaluated against an experimental data set to which participants were blinded. Individual cytotoxicity predictions were better than random, with modest correlations (Pearson's r < 0.28), consistent with complex trait genomic prediction. In contrast, predictions of population-level response to different compounds were higher (r < 0.66). The results highlight the possibility of predicting health risks associated with unknown compounds, although risk estimation accuracy remains suboptimal.

Assessing sediment contamination using six toxicity assays

OpenAIRE

Allen G. BURTON Jr.; Carolyn ROWLAND; Renato BAUDO; Monica BELTRAMI

2001-01-01

An evaluation of sediment toxicity at Lake Orta, Italy was conducted to compare a toxicity test battery of 6 assays and to evaluate the extent of sediment contamination at various sediment depths. Lake Orta received excessive loadings of copper and ammonia during the 1900’s until a large remediation effort was conducted in 1989-90 using lime addition. Since that time, the lake has shown signs of a steady recovery of biological communities. The study results showed acute toxicity still exists ...

Utilization of distillery stillage for energy generation and concurrent production of valuable microalgal biomass in the sequence: Biogas-cogeneration-microalgae-products

Energy Technology Data Exchange (ETDEWEB)

Douskova, Irena; Doucha, Jiri; Zachleder, Vilem [Laboratory of Cell Cycles of Algae, Department of Autotrophic Microorganisms, Institute of Microbiology of the Academy of Sciences of the Czech Republic, Novohradska 237, 379 81 Trebon - Opatovicky mlyn (Czech Republic); Kastanek, Frantisek; Maleterova, Ywette [Institute of Chemical Process Fundamentals of the Academy of Sciences of the Czech Republic, Rozvojova 135, 16502 Prague 6 - Suchdol (Czech Republic); Kastanek, Petr [Biocen, Ltd., Ondrickova 1246/13, 13000 Praha - Zizkov (Czech Republic)

2010-03-15

The aim of the study was the experimental verification of a proposed novel technology of energy and materials production, consisting of the following process steps: production of biogas from agricultural waste (distillery stillage), presumed utilization of biogas for electricity and heat production (cogeneration) in association with its use as a source of carbon dioxide for microalgae cultivation. The microalgal biomass can be hereafter processed to valuable products such as food and feed supplements. A part of the process wastewater can be utilized as a nitrogen source (ammonium ions) for microalgae cultivation, so the whole process is technologically closed. The tests were performed in a pilot-scale device. Optimization of biogas production from distillery stillage is described. The growth kinetics of microalgae Chlorella sp. consuming biogas or mixture of air and carbon dioxide in the concentration range of 2-20% (v/v) (simulating a flue gas from biogas incineration) in laboratory-scale photo-bioreactors are presented. It was proven that the raw biogas (even without the removal of hydrogen sulphide) could be used as a source of carbon dioxide for growth of microalgae. The growth rate of microalgae consuming biogas was the same as the growth rate of the culture grown on a mixture of air and food-grade carbon dioxide. Using biogas as a source of carbon dioxide has two main advantages: the biomass production costs are reduced and the produced biomass does not contain harmful compounds, which can occur in flue gases. The microalgal growth in bubbled cylinders was typically linear with time. The growth rate dependence on the diameter of the photobioreactor can be correlated using an empirical formula M = 2.2 D{sup -0.8} (valid for the linear bubbling velocities in the range of w = 0.1-0.3 cm/s), where M is the growth rate in g/L/h, and D is the photobioreactor diameter in mm. Processing of the fermenter wastewater was also quantified. Particularly the removal of

Utilization of distillery stillage for energy generation and concurrent production of valuable microalgal biomass in the sequence: Biogas-cogeneration-microalgae-products

International Nuclear Information System (INIS)

Douskova, Irena; Kastanek, Frantisek; Maleterova, Ywette; Kastanek, Petr; Doucha, Jiri; Zachleder, Vilem

2010-01-01

The aim of the study was the experimental verification of a proposed novel technology of energy and materials production, consisting of the following process steps: production of biogas from agricultural waste (distillery stillage), presumed utilization of biogas for electricity and heat production (cogeneration) in association with its use as a source of carbon dioxide for microalgae cultivation. The microalgal biomass can be hereafter processed to valuable products such as food and feed supplements. A part of the process wastewater can be utilized as a nitrogen source (ammonium ions) for microalgae cultivation, so the whole process is technologically closed. The tests were performed in a pilot-scale device. Optimization of biogas production from distillery stillage is described. The growth kinetics of microalgae Chlorella sp. consuming biogas or mixture of air and carbon dioxide in the concentration range of 2-20% (v/v) (simulating a flue gas from biogas incineration) in laboratory-scale photo-bioreactors are presented. It was proven that the raw biogas (even without the removal of hydrogen sulphide) could be used as a source of carbon dioxide for growth of microalgae. The growth rate of microalgae consuming biogas was the same as the growth rate of the culture grown on a mixture of air and food-grade carbon dioxide. Using biogas as a source of carbon dioxide has two main advantages: the biomass production costs are reduced and the produced biomass does not contain harmful compounds, which can occur in flue gases. The microalgal growth in bubbled cylinders was typically linear with time. The growth rate dependence on the diameter of the photobioreactor can be correlated using an empirical formula M = 2.2 D -0.8 (valid for the linear bubbling velocities in the range of w = 0.1-0.3 cm/s), where M is the growth rate in g/L/h, and D is the photobioreactor diameter in mm. Processing of the fermenter wastewater was also quantified. Particularly the removal of ammonia

Facts and Fallacies in the Debate on Glyphosate Toxicity

Directory of Open Access Journals (Sweden)

Robin Mesnage

2017-11-01

Full Text Available The safety profile of the herbicide glyphosate and its commercial formulations is controversial. Reviews have been published by individuals who are consultants and employees of companies commercializing glyphosate-based herbicides in support of glyphosate’s reapproval by regulatory agencies. These authors conclude that glyphosate is safe at levels below regulatory permissible limits. In contrast, reviews conducted by academic scientists independent of industry report toxic effects below regulatory limits, as well as shortcomings of the current regulatory evaluation of risks associated with glyphosate exposures. Two authors in particular (Samsel and Seneff have published a series of commentaries proposing that long-term exposure to glyphosate is responsible for many chronic diseases (including cancers, diabetes, neuropathies, obesity, asthma, infections, osteoporosis, infertility, and birth defects. The aim of this review is to examine the evidential basis for these claimed negative health effects and the mechanisms that are alleged to be at their basis. We found that these authors inappropriately employ a deductive reasoning approach based on syllogism. We found that their conclusions are not supported by the available scientific evidence. Thus, the mechanisms and vast range of conditions proposed to result from glyphosate toxicity presented by Samsel and Seneff in their commentaries are at best unsubstantiated theories, speculations, or simply incorrect. This misrepresentation of glyphosate’s toxicity misleads the public, the scientific community, and regulators. Although evidence exists that glyphosate-based herbicides are toxic below regulatory set safety limits, the arguments of Samsel and Seneff largely serve to distract rather than to give a rational direction to much needed future research investigating the toxicity of these pesticides, especially at levels of ingestion that are typical for human populations.

Facts and Fallacies in the Debate on Glyphosate Toxicity

Science.gov (United States)

Mesnage, Robin; Antoniou, Michael N.

2017-01-01

The safety profile of the herbicide glyphosate and its commercial formulations is controversial. Reviews have been published by individuals who are consultants and employees of companies commercializing glyphosate-based herbicides in support of glyphosate’s reapproval by regulatory agencies. These authors conclude that glyphosate is safe at levels below regulatory permissible limits. In contrast, reviews conducted by academic scientists independent of industry report toxic effects below regulatory limits, as well as shortcomings of the current regulatory evaluation of risks associated with glyphosate exposures. Two authors in particular (Samsel and Seneff) have published a series of commentaries proposing that long-term exposure to glyphosate is responsible for many chronic diseases (including cancers, diabetes, neuropathies, obesity, asthma, infections, osteoporosis, infertility, and birth defects). The aim of this review is to examine the evidential basis for these claimed negative health effects and the mechanisms that are alleged to be at their basis. We found that these authors inappropriately employ a deductive reasoning approach based on syllogism. We found that their conclusions are not supported by the available scientific evidence. Thus, the mechanisms and vast range of conditions proposed to result from glyphosate toxicity presented by Samsel and Seneff in their commentaries are at best unsubstantiated theories, speculations, or simply incorrect. This misrepresentation of glyphosate’s toxicity misleads the public, the scientific community, and regulators. Although evidence exists that glyphosate-based herbicides are toxic below regulatory set safety limits, the arguments of Samsel and Seneff largely serve to distract rather than to give a rational direction to much needed future research investigating the toxicity of these pesticides, especially at levels of ingestion that are typical for human populations. PMID:29226121

Community-Level Impacts Projection System (CLIPS). Final report

Energy Technology Data Exchange (ETDEWEB)

Monts, J.K.; Bareiss, E.R.

1979-02-01

The Community-Level Impacts Projection System includes a set of techniques for providing detailed advance information required for rational planning. The computerized system generates reports which enable the user: to describe the energy development activity in terms of its employment demands and spatial location; to estimate how many in-migrating workers will be required; to estimate the demographic characteristics of the in-migrating workers (e.g., how many elementary school children they will bring); to estimate how many additional secondary employment opportunities (e.g., employment in eating and drinking establishments and grocery stores) will be generated; to estimate what the local area's population levels in various age groups would be both with the project and without it; to estimate community population levels for both the impact case and the baseline case; and to estimate the approximate resource requirements and costs for providing additional municipal facilities and services (e.g., water treatment and distribution, wastewater treatment and collection, gas and electric distribution, police and fire protection, etc.)

Determination of toxic and essential elements in blood and milk from female subjects in a Lead contaminated community in Zamfara State, Nigeria

International Nuclear Information System (INIS)

Ojo, J.; Komolafe, O.; Obiajunwa, P.; Ogunba, B.; Adesanmi, C.; Kanoma, M.; Adedeji, S.; Horsvat, M.

2011-01-01

Occurrence of lead poisoning associated with gold mining and processing was reported around March 2010 in some communities of Zamfara State, leading to hundreds of fatalities, especially among children. We have evaluated the levels of lead and other elements (both toxic and essential) in human milk and whole blood samples obtained from 27 subjects at the village of Yargalma, in Anka Local Government Area of Zamfara State. Milk and blood samples were lyophilized at the Obafemi Awolowo University Teaching Hospital Complex, lIe-Ife, and were further sterilized by gamma irradiation (20 -30 kGy) at the National Radiation Centre, Abuja. Elemental analyses were carried out at the Josef Stefan Institute, Ljubljana, Slovenia for determination of Pb, Cd, As, Se, Zn and Cu by ICP-MS; and Hg by Direct Hg analyser. The significant contamination of the environment leading to the reported cases of Pb-poisoning in Zamfara gold mines have been confirmed by elevated levels of Pb measured in samples of blood and human milk. The levels of Pb in blood ranged from 7.9 - 86.8μg/dL (mean±SD: 55.6±19.6μg/dL) while levels of this toxic element in human milk ranged from 2 - 140 ng/ml (mean±SD: 45±37 ng/ml). These values, in asymptomatic subjects, are extremely high indeed. A number of interesting correlations between elemental levels in milk and blood of mothers, and the age of mother and period after birth have also been demonstrated. For instance Mothers age significantly correlates with blood Pb (confirming accumulation in bones which affect blood lead level in lactating mothers). On the other hand, Mother's age significantly correlate negatively with Blood Selenium. Levels of the essential element Zn in both blood and milk of mother significantly correlate negatively with the time elapsed after child delivery (Baby's Age) as is reported in literature. We hesitate to suggest that breast-feeding of babies be limited in these subjects, knowing the several other important nutrients

The Los Angeles County Community Disaster Resilience Project — A Community-Level, Public Health Initiative to Build Community Disaster Resilience

Directory of Open Access Journals (Sweden)

David Eisenman

2014-08-01

Full Text Available Public health officials need evidence-based methods for improving community disaster resilience and strategies for measuring results. This methods paper describes how one public health department is addressing this problem. This paper provides a detailed description of the theoretical rationale, intervention design and novel evaluation of the Los Angeles County Community Disaster Resilience Project (LACCDR, a public health program for increasing community disaster resilience. The LACCDR Project utilizes a pretest–posttest method with control group design. Sixteen communities in Los Angeles County were selected and randomly assigned to the experimental community resilience group or the comparison group. Community coalitions in the experimental group receive training from a public health nurse trained in community resilience in a toolkit developed for the project. The toolkit is grounded in theory and uses multiple components to address education, community engagement, community and individual self-sufficiency, and partnerships among community organizations and governmental agencies. The comparison communities receive training in traditional disaster preparedness topics of disaster supplies and emergency communication plans. Outcome indicators include longitudinal changes in inter-organizational linkages among community organizations, community member responses in table-top exercises, and changes in household level community resilience behaviors and attitudes. The LACCDR Project is a significant opportunity and effort to operationalize and meaningfully measure factors and strategies to increase community resilience. This paper is intended to provide public health and academic researchers with new tools to conduct their community resilience programs and evaluation research. Results are not yet available and will be presented in future reports.

Metal toxicity affects predatory stream invertebrates less than other functional feeding groups

International Nuclear Information System (INIS)

Liess, Matthias; Gerner, Nadine V.; Kefford, Ben J.

2017-01-01

Ecosystem effects of heavy metals need to be identified for a retrospective risk assessment, and potential impacts need to be predicted for a prospective risk assessment. In this study, we established a strong correlation between the toxic pressure of dissolved metals and invertebrate species. We compiled available data from a wide geographical range of Australian streams that were contaminated with heavy metals [mainly copper (Cu) and zinc (Zn)] and the corresponding invertebrate communities. Heavy metal toxicity is positively related to the proportion of predators within the invertebrate community, represented by the predator ratio , with an effect threshold range of 2.6 μg/L - 26 μg/L for Cu and 62 μg/L - 617 μg/L for Zn. These effect concentrations are in the ranges of the concentrations identified in model ecosystems and other field investigations and are just above the existing guideline limits. Heavy metals also affects the taxa richness negatively. Other community measures, such as the evenness, number of EPT (Ephemeroptera, Plecoptera, and Trichoptera) taxa, SPEcies At Risk (SPEAR) pesticides or SPEAR salinity were relatively poorly correlated with heavy metal toxicity in the streams. Therefore, we suggest applying the predator ratio within the community as a starting point for an indicator of the dissolved metal toxicity, the SPEAR metals . - Highlights: • Data on dissolved metals and invertebrates were compiled for a wide geographical range. • Heavy metal toxicity was strongly related to the predator ratio. • Ecologically relevant thresholds identified for Cu and Zn were above the guideline limits. - Increasing metal toxicity for Cu and Zn in streams could be related to an increasing predator ratio within the invertebrate community.

Comparative Toxicity of Nanoparticulate CuO and ZnO to Soil Bacterial Communities

Science.gov (United States)

Rousk, Johannes; Ackermann, Kathrin; Curling, Simon F.; Jones, Davey L.

2012-01-01

The increasing industrial application of metal oxide Engineered Nano-Particles (ENPs) is likely to increase their environmental release to soils. While the potential of metal oxide ENPs as environmental toxicants has been shown, lack of suitable control treatments have compromised the power of many previous assessments. We evaluated the ecotoxicity of ENP (nano) forms of Zn and Cu oxides in two different soils by measuring their ability to inhibit bacterial growth. We could show a direct acute toxicity of nano-CuO acting on soil bacteria while the macroparticulate (bulk) form of CuO was not toxic. In comparison, CuSO4 was more toxic than either oxide form. Unlike Cu, all forms of Zn were toxic to soil bacteria, and the bulk-ZnO was more toxic than the nano-ZnO. The ZnSO4 addition was not consistently more toxic than the oxide forms. Consistently, we found a tight link between the dissolved concentration of metal in solution and the inhibition of bacterial growth. The inconsistent toxicological response between soils could be explained by different resulting concentrations of metals in soil solution. Our findings suggested that the principal mechanism of toxicity was dissolution of metal oxides and sulphates into a metal ion form known to be highly toxic to bacteria, and not a direct effect of nano-sized particles acting on bacteria. We propose that integrated efforts toward directly assessing bioavailable metal concentrations are more valuable than spending resources to reassess ecotoxicology of ENPs separately from general metal toxicity. PMID:22479561

Effective inundation of continental United States communities with 21st century sea level rise

Directory of Open Access Journals (Sweden)

Kristina A. Dahl

2017-07-01

Full Text Available Recurrent, tidally driven coastal flooding is one of the most visible signs of sea level rise. Recent studies have shown that such flooding will become more frequent and extensive as sea level continues to rise, potentially altering the landscape and livability of coastal communities decades before sea level rise causes coastal land to be permanently inundated. In this study, we identify US communities that will face effective inundation—defined as having 10% or more of livable land area flooded at least 26 times per year—with three localized sea level rise scenarios based on projections for the 3rd US National Climate Assessment. We present these results in a new, online interactive tool that allows users to explore when and how effective inundation will impact their communities. In addition, we identify communities facing effective inundation within the next 30 years that contain areas of high socioeconomic vulnerability today using a previously published vulnerability index. With the Intermediate-High and Highest sea level rise scenarios, 489 and 668 communities, respectively, would face effective inundation by the year 2100. With these two scenarios, more than half of communities facing effective inundation by 2045 contain areas of current high socioeconomic vulnerability. These results highlight the timeframes that US coastal communities have to respond to disruptive future inundation. The results also underscore the importance of limiting future warming and sea level rise: under the Intermediate-Low scenario, used as a proxy for sea level rise under the Paris Climate Agreement, 199 fewer communities would be effectively inundated by 2100.

Exploring Environmental Inequity in South Korea: An Analysis of the Distribution of Toxic Release Inventory (TRI Facilities and Toxic Releases

Directory of Open Access Journals (Sweden)

D. K. Yoon

2017-10-01

Full Text Available Recently, location data regarding the Toxic Release Inventory (TRI in South Korea was released to the public. This study investigated the spatial patterns of TRIs and releases of toxic substances in all 230 local governments in South Korea to determine whether spatial clusters relevant to the siting of noxious facilities occur. In addition, we employed spatial regression modeling to determine whether the number of TRI facilities and the volume of toxic releases in a given community were correlated with the community’s socioeconomic, racial, political, and land use characteristics. We found that the TRI facilities and their toxic releases were disproportionately distributed with clustered spatial patterning. Spatial regression modeling indicated that jurisdictions with smaller percentages of minorities, stronger political activity, less industrial land use, and more commercial land use had smaller numbers of toxic releases, as well as smaller numbers of TRI facilities. However, the economic status of the community did not affect the siting of hazardous facilities. These results indicate that the siting of TRI facilities in Korea is more affected by sociopolitical factors than by economic status. Racial issues are thus crucial for consideration in environmental justice as the population of Korea becomes more racially and ethnically diverse.

dEMBF: A Comprehensive Database of Enzymes of Microalgal Biofuel Feedstock.

Science.gov (United States)

Misra, Namrata; Panda, Prasanna Kumar; Parida, Bikram Kumar; Mishra, Barada Kanta

2016-01-01

Microalgae have attracted wide attention as one of the most versatile renewable feedstocks for production of biofuel. To develop genetically engineered high lipid yielding algal strains, a thorough understanding of the lipid biosynthetic pathway and the underpinning enzymes is essential. In this work, we have systematically mined the genomes of fifteen diverse algal species belonging to Chlorophyta, Heterokontophyta, Rhodophyta, and Haptophyta, to identify and annotate the putative enzymes of lipid metabolic pathway. Consequently, we have also developed a database, dEMBF (Database of Enzymes of Microalgal Biofuel Feedstock), which catalogues the complete list of identified enzymes along with their computed annotation details including length, hydrophobicity, amino acid composition, subcellular location, gene ontology, KEGG pathway, orthologous group, Pfam domain, intron-exon organization, transmembrane topology, and secondary/tertiary structural data. Furthermore, to facilitate functional and evolutionary study of these enzymes, a collection of built-in applications for BLAST search, motif identification, sequence and phylogenetic analysis have been seamlessly integrated into the database. dEMBF is the first database that brings together all enzymes responsible for lipid synthesis from available algal genomes, and provides an integrative platform for enzyme inquiry and analysis. This database will be extremely useful for algal biofuel research. It can be accessed at http://bbprof.immt.res.in/embf.

Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production

Directory of Open Access Journals (Sweden)

Adarme-Vega T

2012-07-01

Full Text Available Abstract Omega-3 fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5 and DHA (C22:6 and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.

Lipid extracted microalgal biomass residue as a fertilizer substitute for Zea mays L

Directory of Open Access Journals (Sweden)

Rahulkumar eMaurya

2016-01-01

Full Text Available High volumes of lipid extracted microalgal biomass residues (LMBRs are expected to be produced upon commencement of biodiesel production on a large scale, thus necessitating its value addition for sustainable development. LMBRs of Chlorella variabilis and Lyngbya majuscula were employed to substitute the nitrogen content of recommended rate of fertilizer (RRF for Zea mays L. The pot experiment comprised of 10 treatments, i.e. T1 (No fertilizer; T2 (RRF-120 N: 60 P2O5: 40 K2O kg ha-1; T3 to T6 -100, 75, 50 and 25% N through LMBR of the Chlorella sp., respectively; T7 to T10 -100, 75, 50 and 25% N through LMBR of Lyngbya sp., respectively. It was found that all LMBR substitution treatments were at par to RRF with respect to grain yield production. T10 gave the highest grain yield (65.16 g plant-1, which was closely followed by that (63.48 g plant-1 under T5. T10 also recorded the highest phosphorus and potassium contents in grains. T4 was markedly superior over control in terms of dry matter accumulation (DMA as well as carbohydrate content, which was ascribed to higher pigment content and photosynthetic activity in leaves. Even though considerably lower DMA was obtained in Lyngbya treatments, which might have been due to the presence of some toxic factors, no reduction in grain yield was apparent. The length of the tassel was significantly higher in either of the LMBRs at any substitution rates over RRF, except T6 and T7. The ascorbate peroxidase activity decreased with decreasing dose of Chlorella LMBR, while all the Lyngbya LMBR treatments recorded lower activity, which were at par with each other. Among the Chlorella treatments, only T5 recorded significantly higher values of glutathione reductase activity over RRF, while the rest were at par. There were significant increases in carbohydrate and crude fat, respectively, only in T4 and T3 over RRF, while no change was observed in crude protein due to LMBR treatments. Apparently, there was no

Macro-level implicit HIV prejudice and the health of community residents with HIV.

Science.gov (United States)

Miller, Carol T; Varni, Susan E; Solomon, Sondra E; DeSarno, Michael J; Bunn, Janice Y

2016-08-01

This study examined how community levels of implicit HIV prejudice are associated with the psychological and physical well-being of people with HIV living in those same communities. It also examined whether community motivation to control prejudice and/or explicit HIV prejudice moderates the relationship of implicit prejudice and well-being. Participants were 206 people with HIV living in 42 different communities in New England who completed measures that assessed psychological distress, thriving, and physical well-being. Telephone surveys of 347 residents of these same communities (selected via random digit dialing) were used to assess community explicit HIV prejudice and motivation to control HIV prejudice. These community residents then completed an online measure of implicit prejudice toward people with HIV, the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998). Multilevel analyses showed that higher community implicit HIV prejudice was associated with greater psychological distress among residents with HIV living in that community. The physical well-being of participants with HIV was negatively related to community implicit HIV prejudice in communities in which residents were unmotivated to control HIV prejudice or had high levels of explicit HIV prejudice. These findings indicate that implicit prejudice of residents of real-world communities may create an environment that may impair the well-being of stigmatized people. Implicit prejudice can therefore be considered an element of macro-level or structural stigma. The discussion considered the possible role of implicit HIV prejudice on a community's social capital as a pathway by which it compromises the well-being of residents with HIV. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Microalgal CO2 sequestering – Modeling microalgae production costs

International Nuclear Information System (INIS)

Bilanovic, Dragoljub; Holland, Mark; Armon, Robert

2012-01-01

Highlights: ► Microalgae production costs were modeled as a function of specific expenses. ► The effects of uncontrollable expenses/factors were incorporated into the model. ► Modeled microalgae production costs were in the range $102–1503 t −1 ha −1 y −1 . - Abstract: Microalgae CO 2 sequestering facilities might become an industrial reality if microalgae biomass could be produced at cost below $500.00 t −1 . We develop a model for estimation of total production costs of microalgae as a function of known production-specific expenses, and incorporate into the model the effects of uncontrollable factors which affect known production-specific expenses. Random fluctuations were intentionally incorporated into the model, consequently into generated cost/technology scenarios, because each and every logically interconnected equipment/operation that is used in design/construction/operation/maintenance of a production process is inevitably subject to random cost/price fluctuations which can neither be eliminated nor a priori controlled. A total of 152 costs/technology scenarios were evaluated to find 44 scenarios in which predicted total production costs of microalgae (PTPCM) was in the range $200–500 t −1 ha −1 y −1 . An additional 24 scenarios were found with PTCPM in the range of $102–200 t −1 ha −1 y −1 . These findings suggest that microalgae CO 2 sequestering and the production of commercial compounds from microalgal biomass can be economically viable venture even today when microalgae production technology is still far from its optimum.

Population-level assessments should be emphasized over community/ecosystem-level assessments. Environmental Sciences Division Publication No. 1535

International Nuclear Information System (INIS)

Van Winkle, W.

1980-01-01

Arguments are presented in favor of emphasizing population-level assessments over community/ecosystem-level assessments. The two approaches are compared on each of four issues: (1) the nature of entrainment/impingement impacts; (2) the ability to forecast reliably for a single fish population as contrasted to the ability to forecast for an aquatic community or ecosystem; (3) practical considerations involving money, manpower, time, and the need to make decisions; and (4) the nature of societal and economic concerns. The conclusion on each of these four issues is that population-level assessments provide the optimal approach for evaluating the effects of entrainment and impingement mortality

Living in highly dynamic polluted river floodplains, do contaminants contribute to population and community effects?

International Nuclear Information System (INIS)

Klok, Chris; Kraak, Michiel H.S.

2008-01-01

The aim of this paper was to collect evidence for the effects of contaminants on biota in a highly dynamic river Rhine floodplain. To this purpose we reviewed the results of circa 10 studies performed in this floodplain. The floodplain was contaminated with elevated levels of cadmium, copper, PAHs, and PCBs and high levels of zinc which were at some sites above legislative values. The results showed that the present contaminants were accumulated by the floodplain inhabiting organisms, but meanwhile population and community effects were ambiguous. Only for the mayfly Ephoron virgo clear effects were detected at the level of the single floodplain. The absence of clear population and community effects is puzzling since at lower contaminant concentrations adverse effects were detected in other environments. Factors that may mask toxic effects include flooding and food quality and quantity. We conclude that given the site specific conditions, being an open, eutrophic system with a highly dynamic flooding pattern, assessment of the contribution of toxicants to observed population density or biomass and community composition requires 1] an increase in number of replicates; 2] a larger scale of investigation and 3] comparison to stable systems with comparable contamination levels

Continuous microalgal cultivation in a laboratory-scale photobioreactor under seasonal day-night irradiation: experiments and simulation.

Science.gov (United States)

Bertucco, Alberto; Beraldi, Mariaelena; Sforza, Eleonora

2014-08-01

In this work, the production of Scenedesmus obliquus in a continuous flat-plate laboratory-scale photobioreactor (PBR) under alternated day-night cycles was tested both experimentally and theoretically. Variation of light intensity according to the four seasons of the year were simulated experimentally by a tunable LED lamp, and effects on microalgal growth and productivity were measured to evaluate the conversion efficiency of light energy into biomass during the different seasons. These results were used to validate a mathematical model for algae growth that can be applied to simulate a large-scale production unit, carried out in a flat-plate PBR of similar geometry. The cellular concentration in the PBR was calculated in both steady-state and transient conditions, and the value of the maintenance kinetic term was correlated to experimental profiles. The relevance of this parameter was finally outlined.

Novel schemes for production of biodiesel and value-added co-products from microalgal oil using heterogeneous catalysts

Science.gov (United States)

Dong, Tao

Microalgae are promising sources of biofuels primarily because of their higher potential productivity compared to terrestrial biofuel crops. However, the production of liquid fuels from microalgae suffers from a lack of viable methods of extraction, conversion and fractionation of various components of the algal biomass. In this dissertation study, a rapid method was developed to accurately evaluate the biodiesel potential of microalgae biomass. The major advantage of this method is in situ fatty acid methyl ester (FAME) preparation directly from wet fresh microalgal and yeast biomass, without prior solvent extraction or dehydration. FAMEs were prepared by a sequential alkaline hydrolysis and acidic esterification process. This method can be used even with high amount of water in the biomass and is applicable to a vast range of microalgae and yeast species. A two-step in situ process was also investigated in this study to obtain a high FAME yield from microalgae biomass that had high free fatty acids (FFA) content. This process has the potential to reduce the production cost of microalgae-derived FAME and be more environmental compatible due to the higher FAME yield with reduced catalyst consumption. A cost-effective bio-char based catalyst was tested for the two-step biodiesel production. The results indicated that the bio-char catalyst was superior to commercial Amberly-15. A scalable chlorophyll remove process was also developed as a part of the system. The research resulted in a practical and cost-effective approach for producing biodiesel from crude microalgal oil. An integrated approach was explored in the fourth part of the study to produce biodiesel and fractionate high-value polyunsaturated fatty acid (PUFA). Zeolites were employed as the catalyst for selective esterification of fatty acids according to their chain length and degree of saturation. Low-value short chain FFA could be largely converted into FAME, while PUFA would remain unreacted due to

Identifying individual- and population-level characteristics that influence rates of risky alcohol consumption in regional communities.

Science.gov (United States)

Breen, Courtney; Shakeshaft, Anthony; Sanson-Fisher, Rob; D'Este, Catherine; Mattick, Richard P; Gilmour, Stuart

2014-02-01

To examine the extent to which individual- and community- level characteristics account for differences in risky alcohol consumption. A cross-sectional postal survey of 2,977 randomly selected individuals from 20 regional communities in NSW, Australia. Individuals drinking at harmful levels on the AUDIT and for risk of harm in the short term and long-term were identified. Multi-level modelling of the correlates of risky alcohol consumption at the individual and community level was conducted. There were differences between communities in alcohol consumption patterns. Being male, unmarried and reporting worse health were significant individual-level correlates for drinking at levels for risk of harm in the long term. The number of GPs (+) and police (-) were significant community characteristics. Being younger (≤25), unmarried, Australian born and with a larger income was associated with drinking at levels for risk of harm in the short term and harmful drinking on the AUDIT. The number of hotels and clubs was positively associated with drinking at levels for risk of harm in the short term. Rates of risky drinking vary significantly between communities and both individual and community characteristics are significantly associated with risky alcohol consumption. A combination of individual- and population-level interventions, tailored to the risk profile of individual communities, is most likely to be optimally effective. © 2014 The Authors. ANZJPH © 2014 Public Health Association of Australia.

Effects of temperature and irradiance on a benthic microalgal community: A combined two-dimensional oxygen and fluorescence imaging approach

DEFF Research Database (Denmark)

Hancke, Kasper; Sorrell, Brian Keith; Lund-Hansen, Lars Chresten

2014-01-01

The effects of temperature and light on both oxygen (O2) production and gross photosynthesis were resolved in a benthic microalgae community by combining two-dimensional (2D) imaging of O2 and variable chlorophyll a (Chl a) fluorescence. Images revealed a photosynthetically active community...... microbial community, at different temperatures. The present imaging approach demonstrates a great potential to study consequences of environmental effects on photosynthetic activity and O2 turnover in complex phototrophic benthic communities....

Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams

Science.gov (United States)

Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara J.; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L.

2018-01-01

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water—atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim—were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May–June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July–August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most

Anaerobic toxicity of cationic silver nanoparticles

International Nuclear Information System (INIS)

Gitipour, Alireza; Thiel, Stephen W.; Scheckel, Kirk G.; Tolaymat, Thabet

2016-01-01

The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag"+ under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged polyvinylpyrrolidone coated AgNPs (PVP-AgNPs) and (3) positively charged branched polyethyleneimine coated AgNPs (BPEI-AgNPs). The AgNPs investigated in this experiment were similar in size (10–15 nm), spherical in shape, but varied in surface charge which ranged from highly negative to highly positive. While, at AgNPs concentrations lower than 5 mg L"−"1, the anaerobic decomposition process was not influenced by the presence of the nanoparticles, there was an observed impact on the diversity of the microbial community. At elevated concentrations (100 mg L"−"1 as silver), only the cationic BPEI-AgNPs demonstrated toxicity similar in magnitude to that of Ag"+. Both citrate and PVP-AgNPs did not exhibit toxicity at the 100 mg L"−"1 as measured by biogas evolution. These findings further indicate the varying modes of action for nanoparticle toxicity and represent one of the few studies that evaluate end-of-life management concerns with regards to the increasing use of nanomaterials in our everyday life. These findings also highlight some of the concerns with a one size fits all approach to the evaluation of environmental health and safety concerns associated with the use of nanoparticles. - Highlights: • At concentrations -1 the anaerobic decomposition process was not impacted. • An impact on the microbial community at concentrations -1 were observed. • At high concentrations (100 mg L"−"1), the cationic BPEI-AgNPs demonstrated toxicity. • Toxicity was demonstrated without the presence of oxidative dissolution of silver. • A one size fits all approach for the evaluation of NPs may not be accurate.

Intraspecific variation shapes community-level behavioral responses to urbanization in spiders.

Science.gov (United States)

Dahirel, Maxime; Dierick, Jasper; De Cock, Maarten; Bonte, Dries

2017-09-01

Urban areas are an extreme example of human-changed environments, exposing organisms to multiple and strong selection pressures. Adaptive behavioral responses are thought to play a major role in animals' success or failure in such new environments. Approaches based on functional traits have proven especially valuable to understand how species communities respond to environmental gradients. Until recently, they have, however, often ignored the potential consequences of intraspecific trait variation (ITV). When ITV is prevalent, it may highly impact ecological processes and resilience against stressors. This may be especially relevant in animals, in which behavioral traits can be altered very flexibly at the individual level to track environmental changes. We investigated how species turnover and ITV influenced community-level behavioral responses in a set of 62 sites of varying levels of urbanization, using orb web spiders and their webs as models of foraging behavior. ITV alone explained around one-third of the total trait variation observed among communities. Spider web structure changed according to urbanization, in ways that increase the capture efficiency of webs in a context of smaller urban prey. These trait shifts were partly mediated by species turnover, but ITV increased their magnitude, potentially helping to buffer the effects of environmental changes on communities. The importance of ITV varied depending on traits and on the spatial scale at which urbanization was considered. Despite being neglected from community-level analyses in animals, our results highlight the importance of accounting for intraspecific trait variation to fully understand trait responses to (human-induced) environmental changes and their impact on ecosystem functioning. © 2017 by the Ecological Society of America.

Functional and community-level soil microbial responses to zinc addition may depend on test system biocomplexity.

Science.gov (United States)

Sverdrup, Line E; Linjordet, Roar; Strømman, Gjermund; Hagen, Snorre B; van Gestel, Cornelis A M; Frostegård, Sa; Sørheim, Roald

2006-12-01

The effect of zinc on soil nitrification and composition of the microbial community in soil was investigated using a full factorial experiment with five zinc concentrations and four levels of biological complexity (microbes only, microbes and earthworms (Eisenia fetida), microbes and Italian ryegrass (Lolium multiflorum var. Macho), and microbes, ryegrass and earthworms). After 6 weeks of exposure, the activity of soil nitrifying bacteria was measured and the microbial community structure was characterized by phospholipid fatty acid (PLFA) analysis. Soil nitrification and several PLFA markers were significantly influenced by either zinc addition and/or the presence of earthworms or ryegrass, and one of the most pronounced changes was the increase of fungi and decrease of bacteria with increasing concentrations of zinc. Of particular interest, however, was the potential interaction between the presence of plants and/or earthworms and the effect of zinc, which the factorial study design allowed us to explore. Such an effect was observed in two cases: Earthworms reduced the positive effect of zinc on the fungal biomass (ANOVA, p=0.03), and the effect of earthworms on the soil nitrification activity depended on zinc concentration (ANOVA, p<0.05). The effect of earthworm presence was not very large, but it does show that multispecies tests might give information about metal toxicity or bioavailability that cannot be predicted from single-species tests.

Individual v. community-level measures of women's decision-making ...

African Journals Online (AJOL)

Individual v. community-level measures of women's decision-making involvement and ... participation for child survival in sub-Saharan Africa is limited. ... Multilevel discrete-time hazard models were employed to investigate the net effect of ...

Serum Creatinine Versus Plasma Methotrexate Levels to Predict Toxicities in Children Receiving High-dose Methotrexate.

Science.gov (United States)

Tiwari, Priya; Thomas, M K; Pathania, Subha; Dhawan, Deepa; Gupta, Y K; Vishnubhatla, Sreenivas; Bakhshi, Sameer

2015-01-01

Facilities for measuring methotrexate (MTX) levels are not available everywhere, potentially limiting administration of high-dose methotrexate (HDMTX). We hypothesized that serum creatinine alteration after HDMTX administration predicts MTX clearance. Overall, 122 cycles in 50 patients of non-Hodgkin lymphoma or acute lymphoblastic leukemia aged ≤18 years receiving HDMTX were enrolled prospectively. Plasma MTX levels were measured at 12, 24, 36, 48, 60, and 72 hours; serum creatinine was measured at baseline, 24, 48, and 72 hours. Correlation of plasma MTX levels with creatinine levels and changes in creatinine from baseline (Δ creatinine) were evaluated. Plasma MTX levels at 72 hours showed positive correlation with serum creatinine at 48 hours (P = .011) and 72 hours (P = .013) as also Δ creatinine at 48 hours (P = .042) and 72 hours (P = .045). However, cut-off value of either creatinine or Δ creatinine could not be established to reliably predict delayed MTX clearance. Greater than 50% Δ creatinine at 48 and 72 hours significantly predicted grade 3/4 leucopenia (P = .036 and P = .001, respectively) and thrombocytopenia (P = .012 and P = .009, respectively) but not mucositis (P = .827 and P = .910, respectively). Delayed MTX elimination did not predict any grade 3/4 toxicity. In spite of demonstration of significant correlation between serum creatinine and Δ creatinine with plasma MTX levels at 72 hours, cut-off value of either variable to predict MTX delay could not be established. Thus, either of these cannot be used as a surrogate for plasma MTX estimation. Interestingly, Δ creatinine effectively predicted hematological toxicities, which were not predicted by delayed MTX clearance.

Modeling the transformation of atmospheric CO2 into microalgal biomass.

Science.gov (United States)

Hasan, Mohammed Fahad; Vogt, Frank

2017-10-23

Marine phytoplankton acts as a considerable sink of atmospheric CO 2 as it sequesters large quantities of this greenhouse gas for biomass production. To assess microalgae's counterbalancing of global warming, the quantities of CO 2 they fix need to be determined. For this task, it is mandatory to understand which environmental and physiological parameters govern this transformation from atmospheric CO 2 to microalgal biomass. However, experimental analyses are challenging as it has been found that the chemical environment has a major impact on the physiological properties of the microalgae cells (diameter typ. 5-20 μm). Moreover, the cells can only chemically interact with their immediate vicinity and thus compound sequestration needs to be studied on a microscopic spatial scale. Due to these reasons, computer simulations are a more promising approach than the experimental studies. Modeling software has been developed that describes the dissolution of atmospheric CO 2 into oceans followed by the formation of HCO 3 - which is then transported to individual microalgae cells. The second portion of this model describes the competition of different cell species for this HCO 3 - , a nutrient, as well as its uptake and utilization for cell production. Two microalgae species, i.e. Dunaliella salina and Nannochloropsis oculata, were cultured individually and in a competition situation under different atmospheric CO 2 conditions. It is shown that this novel model's predictions of biomass production are in very good agreement with the experimental flow cytometry results. After model validation, it has been applied to long-term prediction of phytoplankton generation. These investigations were motivated by the question whether or not cell production slows down as cultures grow. This is of relevance as a reduced cell production rate means that the increase in a culture's CO 2 -sinking capacity slows down as well. One implication resulting from this is that an increase in

Cd toxicity in Ash amended to plantations; the dilemma of different answers at different levels of description

DEFF Research Database (Denmark)

Christensen, Søren; Ekelund, Flemming; Kjøller, Rasmus

2018-01-01

. Other more abundant cations like Zn regulate Cd uptake. Mycorrhiza reduce Cd uptake in several plants. In barley Cd gradually decrease from root via stem to seeds. In conclusion for ash amounts up to 10 t/ha, we do not find metal toxicity of ash or evidence for bioaccumulation of metals in soil...... growth, equally because of the pH increase and the nutrients added. The pH increase stimulates decomposition activity. Soil carbon availability is not permanently increased with ash amendment, however, which may suggest that decomposition increase is coupled to primary production increase. Plantation....... Wood ash increase plantation soil Cd, and so did Cd in grass although at a very low level, Cd in lichens and Cd in the small biomass of earthworms. The toxicity of Cd is regulated by metal binding to soil being several orders of magnitude lower than in pure liquid. Ash is toxic towards microarthropods...

Model ecosystem approach to estimate community level effects of radiation

Energy Technology Data Exchange (ETDEWEB)

Masahiro, Doi; Nobuyuki, Tanaka; Shoichi, Fuma; Nobuyoshi, Ishii; Hiroshi, Takeda; Zenichiro, Kawabata [National Institute of Radiological Sciences, Environmental and Toxicological Sciences Research Group, Chiba (Japan)

2004-07-01

Mathematical computer model is developed to simulate the population dynamics and dynamic mass budgets of the microbial community realized as a self sustainable aquatic ecological system in the tube. Autotrophic algae, heterotrophic protozoa and sapro-trophic bacteria live symbiotically with inter-species' interactions as predator-prey relationship, competition for the common resource, autolysis of detritus and detritus-grazing food chain, etc. The simulation model is the individual-based parallel model, built in the demographic stochasticity, environmental stochasticity by dividing the aquatic environment into patches. Validity of the model is checked by the multifaceted data of the microcosm experiments. In the analysis, intrinsic parameters of umbrella endpoints (lethality, morbidity, reproductive growth, mutation) are manipulated at the individual level, and tried to find the population level, community level and ecosystem level disorders of ecologically crucial parameters (e.g. intrinsic growth rate, carrying capacity, variation, etc.) that related to the probability of population extinction. (author)

Model ecosystem approach to estimate community level effects of radiation

International Nuclear Information System (INIS)

Masahiro, Doi; Nobuyuki, Tanaka; Shoichi, Fuma; Nobuyoshi, Ishii; Hiroshi, Takeda; Zenichiro, Kawabata

2004-01-01

Mathematical computer model is developed to simulate the population dynamics and dynamic mass budgets of the microbial community realized as a self sustainable aquatic ecological system in the tube. Autotrophic algae, heterotrophic protozoa and sapro-trophic bacteria live symbiotically with inter-species' interactions as predator-prey relationship, competition for the common resource, autolysis of detritus and detritus-grazing food chain, etc. The simulation model is the individual-based parallel model, built in the demographic stochasticity, environmental stochasticity by dividing the aquatic environment into patches. Validity of the model is checked by the multifaceted data of the microcosm experiments. In the analysis, intrinsic parameters of umbrella endpoints (lethality, morbidity, reproductive growth, mutation) are manipulated at the individual level, and tried to find the population level, community level and ecosystem level disorders of ecologically crucial parameters (e.g. intrinsic growth rate, carrying capacity, variation, etc.) that related to the probability of population extinction. (author)

Reduction of environmental and energy footprint of microalgal biodiesel production through material and energy integration.

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Chowdhury, Raja; Viamajala, Sridhar; Gerlach, Robin

2012-03-01

The life cycle impacts were assessed for an integrated microalgal biodiesel production system that facilitates energy- and nutrient- recovery through anaerobic digestion, and utilizes glycerol generated within the facility for additional heterotrophic biodiesel production. Results show that when external fossil energy inputs are lowered through process integration, the energy demand, global warming potential (GWP), and process water demand decrease significantly and become less sensitive to algal lipid content. When substitution allocation is used to assign additional credit for avoidance of fossil energy use (through utilization of recycled nutrients and biogas), GWP and water demand can, in fact, increase with increase in lipid content. Relative to stand-alone algal biofuel facilities, energy demand can be lowered by 3-14 GJ per ton of biodiesel through process integration. GWP of biodiesel from the integrated system can be lowered by up to 71% compared to petroleum fuel. Evaporative water loss was the primary water demand driver. Copyright © 2011 Elsevier Ltd. All rights reserved.

Migration and child immunization in Nigeria: individual- and community-level contexts

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Antai Diddy

2010-03-01

Full Text Available Abstract Background Vaccine-preventable diseases are responsible for severe rates of morbidity and mortality in Africa. Despite the availability of appropriate vaccines for routine use on infants, vaccine-preventable diseases are highly endemic throughout sub-Saharan Africa. Widespread disparities in the coverage of immunization programmes persist between and within rural and urban areas, regions and communities in Nigeria. This study assessed the individual- and community-level explanatory factors associated with child immunization differentials between migrant and non-migrant groups. Methods The proportion of children that received each of the eight vaccines in the routine immunization schedule in Nigeria was estimated. Multilevel multivariable regression analysis was performed using a nationally representative sample of 6029 children from 2735 mothers aged 15-49 years and nested within 365 communities. Odds ratios with 95% confidence intervals were used to express measures of association between the characteristics. Variance partition coefficients and Wald statistic i.e. the ratio of the estimate to its standard error were used to express measures of variation. Results Individual- and community contexts are strongly associated with the likelihood of receiving full immunization among migrant groups. The likelihood of full immunization was higher for children of rural non-migrant mothers compared to children of rural-urban migrant mothers. Findings provide support for the traditional migration perspectives, and show that individual-level characteristics, such as, migrant disruption (migration itself, selectivity (demographic and socio-economic characteristics, and adaptation (health care utilization, as well as community-level characteristics (region of residence, and proportion of mothers who had hospital delivery are important in explaining the differentials in full immunization among the children. Conclusion Migration is an important

The Use of Information by Policymakers at the Local Community Level.

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Florio, Evelyn; DeMartini, Joseph R.

1993-01-01

Discussion of decision making focuses on a study that was conducted to examine how policymakers at the local community level use social science information in making decisions. The use of social science information and other information sources in two communities examining health care issues is described. (Contains 18 references.) (LRW)

2004 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

Energy Technology Data Exchange (ETDEWEB)

M. Stockton

2006-01-15

Section 313 of Emergency Planning and Community Right-to-Know Act (EPCRA) specifically requires facilities to submit a Toxic Chemical Release Inventory Report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. For reporting year 2004, Los Alamos National Laboratory (LANL or the Laboratory) submitted Form R reports for lead compounds, nitric acid, and nitrate compounds as required under the EPCRA Section 313. No other EPCRA Section 313 chemicals were used in 2004 above the reportable thresholds. This document provides a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2004, as well as background information about data included on the Form R reports.

Mechanisms and manifestations of toxic actions at the bone tissue level; Mecanismes et manifestations de l'action des toxiques au niveau du tissu osseux

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-07-01

The principal abnormalities determined by toxic at the bone level are: osteoporosis, osteomalacia, osteosclerosis or osteopetrosis. The principal toxics having a noxiousness at the bone level are: the fluorine, the phosphorus, the lead, the bismuth, the cadmium and the strontium. The strontium 90 has an important radioactivity that gives at the bone level osteosarcomas or at low doses, leukemoid reactions and marrow angiosarcoma. (N.C.)

Community-level climate change vulnerability research: trends, progress, and future directions

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McDowell, Graham; Ford, James; Jones, Julie

2016-03-01

This study systematically identifies, characterizes, and critically evaluates community-level climate change vulnerability assessments published over the last 25 years (n = 274). We find that while the field has advanced considerably in terms of conceptual framing and methodological approaches, key shortcomings remain in how vulnerability is being studied at the community-level. We argue that vulnerability research needs to more critically engage with the following: methods for evaluating future vulnerability, the relevance of vulnerability research for decision-making, interdependencies between social and ecological systems, attention to researcher / subject power dynamics, critical interpretation of key terms, and consideration of the potentially positive opportunities presented by a changing climate. Addressing these research needs is necessary for generating knowledge that supports climate-affected communities in navigating the challenges and opportunities ahead.

Comparative responses of river biofilms at the community level to common organic solvent and herbicide exposure.

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Paule, A; Roubeix, V; Swerhone, G D W; Roy, J; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L; Lawrence, J R

2016-03-01

Residual pesticides applied to crops migrate from agricultural lands to surface and ground waters. River biofilms are the first aquatic non-target organisms which interact with pesticides. Therefore, ecotoxicological experiments were performed at laboratory scale under controlled conditions to investigate the community-level responses of river biofilms to a chloroacetanilide herbicide (alachlor) and organic solvent (methanol) exposure through the development referenced to control. Triplicate rotating annular bioreactors, inoculated with river water, were used to cultivate river biofilms under the influence of 1 and 10 μg L(-1) of alachlor and 25 mg L(-1) of methanol. For this purpose, functional (thymidine incorporation and carbon utilization spectra) and structural responses of microbial communities were assessed after 5 weeks of development. Structural aspects included biomass (chlorophyll a, confocal laser scanning microscopy) and composition (fluor-conjugated lectin binding, molecular fingerprinting, and diatom species composition). The addition of alachlor resulted in a significant reduction of bacterial biomass at 1 μg L(-1), whereas at 10 μg L(-1), it induced a significant reduction of exopolymer lectin binding, algal, bacterial, and cyanobacterial biomass. However, there were no changes in biofilm thickness or thymidine incorporation. No significant difference between the bacterial community structures of control and alachlor-treated biofilms was revealed by terminal restriction fragment length polymorphism (T-RFLP) analyses. However, the methanol-treated bacterial communities appeared different from control and alachlor-treated communities. Moreover, methanol treatment resulted in an increase of bacterial biomass and thymidine incorporation as well. Changes in dominant lectin binding suggested changes in the exopolymeric substances and community composition. Chlorophyll a and cyanobacterial biomass were also altered by methanol. This study suggested

Effects of silver nitrate and silver nanoparticles on a planktonic community: general trends after short-term exposure.

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Jens Boenigk

Full Text Available Among metal pollutants silver ions are one of the most toxic forms, and have thus been assigned to the highest toxicity class. Its toxicity to a wide range of microorganisms combined with its low toxicity to humans lead to the development of a wealth of silver-based products in many bactericidal applications accounting to more than 1000 nano-technology-based consumer products. Accordingly, silver is a widely distributed metal in the environment originating from its different forms of application as metal, salt and nanoparticle. A realistic assessment of silver nanoparticle toxicity in natural waters is, however, problematic and needs to be linked to experimental approaches. Here we apply metatranscriptome sequencing allowing for elucidating reactions of whole communities present in a water sample to stressors. We compared the toxicity of ionic silver and ligand-free silver nanoparticles by short term exposure on a natural community of aquatic microorganisms. We analyzed the effects of the treatments on metabolic pathways and species composition on the eukaryote metatranscriptome level in order to describe immediate molecular responses of organisms using a community approach. We found significant differences between the samples treated with 5 µg/L AgNO3 compared to the controls, but no significant differences in the samples treated with AgNP compared to the control samples. Statistical analysis yielded 126 genes (KO-IDs with significant differential expression with a false discovery rate (FDR <0.05 between the control (KO and AgNO3 (NO3 groups. A KEGG pathway enrichment analysis showed significant results with a FDR below 0.05 for pathways related to photosynthesis. Our study therefore supports the view that ionic silver rather than silver nanoparticles are responsible for silver toxicity. Nevertheless, our results highlight the strength of metatranscriptome approaches for assessing metal toxicity on aquatic communities.

A robust bioassay to assess the toxicity of metals to the Antarctic marine microalga Phaeocystis antarctica.

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Gissi, Francesca; Adams, Merrin S; King, Catherine K; Jolley, Dianne F

2015-07-01

Despite evidence of contamination in Antarctic coastal marine environments, no water-quality guidelines have been established for the region because of a paucity of biological effects data for local Antarctic species. Currently, there is limited information on the sensitivity of Antarctic microalgae to metal contamination, which is exacerbated by the lack of standard toxicity testing protocols for local marine species. In the present study, a routine and robust toxicity test protocol was developed using the Antarctic marine microalga Phaeocystis antarctica, and its sensitivity was investigated following 10-d exposures to dissolved copper, cadmium, lead, zinc, and nickel. In comparisons of 10% inhibition of population growth rate (IC10) values, P. antarctica was most sensitive to copper (3.3 μg/L), followed by cadmium (135 μg/L), lead (260 μg/L), and zinc (450 μg/L). Although an IC10 value for nickel could not be accurately estimated, the no-observed-effect concentration value for nickel was 1070 μg/L. Exposure to copper and cadmium caused changes in internal cell granularity and increased chlorophyll a fluorescence. Lead, zinc, and nickel had no effect on any of the cellular parameters measured. The present study provides valuable metal-ecotoxicity data for an Antarctic marine microalga, with P. antarctica representing one of the most sensitive microalgal species to dissolved copper ever reported when compared with temperate and tropical species. © 2015 SETAC.

Six-month low level chlorine dioxide gas inhalation toxicity study with two-week recovery period in rats

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Akamatsu Akinori

2012-02-01

Full Text Available Abstract Background Chlorine dioxide (CD gas has a potent antimicrobial activity at extremely low concentration and may serve as a new tool for infection control occupationally as well as publicly. However, it remains unknown whether the chronic exposure of CD gas concentration effective against microbes is safe. Therefore, long-term, low concentration CD gas inhalation toxicity was studied in rats as a six-month continuous whole-body exposure followed by a two-week recovery period, so as to prove that the CD gas exposed up to 0.1 ppm (volume ratio is judged as safe on the basis of a battery of toxicological examinations. Methods CD gas at 0.05 ppm or 0.1 ppm for 24 hours/day and 7 days/week was exposed to rats for 6 months under an unrestrained condition with free access to chow and water in a chamber so as to simulate the ordinary lifestyle in human. The control animals were exposed to air only. During the study period, the body weight as well as the food and water consumptions were recorded. After the 6-month exposure and the 2-week recovery period, animals were sacrificed and a battery of toxicological examinations, including biochemistry, hematology, necropsy, organ weights and histopathology, were performed. Results Well regulated levels of CD gas were exposed throughout the chamber over the entire study period. No CD gas-related toxicity sign was observed during the whole study period. No significant difference was observed in body weight gain, food and water consumptions, and relative organ weight. In biochemistry and hematology examinations, changes did not appear to be related to CD gas toxicity. In necropsy and histopathology, no CD gas-related toxicity was observed even in expected target respiratory organs. Conclusions CD gas up to 0.1 ppm, exceeding the level effective against microbes, exposed to whole body in rats continuously for six months was not toxic, under a condition simulating the conventional lifestyle in human.

The Progranulin Cleavage Products, Granulins, Exacerbate TDP-43 Toxicity and Increase TDP-43 Levels.

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Salazar, Dominique A; Butler, Victoria J; Argouarch, Andrea R; Hsu, Tsung-Yuan; Mason, Amanda; Nakamura, Ayumi; McCurdy, Helen; Cox, David; Ng, Rachel; Pan, Gloria; Seeley, William W; Miller, Bruce L; Kao, Aimee W

2015-06-24

Mutations in the human progranulin gene resulting in protein haploinsufficiency cause frontotemporal lobar degeneration with TDP-43 inclusions. Although progress has been made in understanding the normal functions of progranulin and TDP-43, the molecular interactions between these proteins remain unclear. Progranulin is proteolytically processed into granulins, but the role of granulins in the pathogenesis of neurodegenerative disease is unknown. We used a Caenorhabditis elegans model of neuronal TDP-43 proteinopathy to specifically interrogate the contribution of granulins to the neurodegenerative process. Complete loss of the progranulin gene did not worsen TDP-43 toxicity, whereas progranulin heterozygosity did. Interestingly, expression of individual granulins alone had little effect on behavior. In contrast, when granulins were coexpressed with TDP-43, they exacerbated its toxicity in a variety of behaviors including motor coordination. These same granulins increased TDP-43 levels via a post-translational mechanism. We further found that in human neurodegenerative disease subjects, granulin fragments accumulated specifically in diseased regions of brain. To our knowledge, this is the first demonstration of a toxic role for granulin fragments in a neurodegenerative disease model. These studies suggest that presence of cleaved granulins, rather than or in addition to loss of full-length progranulin, may contribute to disease in TDP-43 proteinopathies. Copyright © 2015 the authors 0270-6474/15/359315-14$15.00/0.

Community- and family-level factors influence care-giver choice to screen blood lead levels of children in a mining community.

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Moodie, S M; Tsui, E K; Silbergeld, E K

2010-07-01

Bunker Hill, in Kellogg, Idaho, formerly a lead mine (1884-1981) and smelter (1917-1981), is now a Superfund site listed on the Environmental Protection Agency's (EPA) National Priorities List. Lead contamination from the site is widespread due to past smelter discharges to land, water, and air, placing children at risk for both exposure to lead and resultant health effects of lead. Since 1983, the EPA has used child blood lead levels to inform the clean-up standards for the Bunker Hill Superfund site. This study was undertaken to examine factors that have contributed to the significant fall-off in the rates and numbers of children being screened for blood lead in Kellogg (number screened decreased from 195 to 8 from 2002 to 2007). The goal of this research project was to define community- and family-level factors which influence care-giver choice to screen blood lead levels of their children in this environment. This formative research study used mixed methods and was comprised of three research components: (1) preliminary interviews using community-based participatory research methods to define key research questions of relevance to community members, government and NGOs working in relation to the Bunker Hill clean-up; (2) a quantitative analysis of a cross-sectional household survey conducted with adult care-givers about child blood lead screening in Kellogg; and (3) ethnographic community rapid assessment methods formed the in-depth interview process and qualitative analysis. The survey showed the likelihood of blood lead screening that for children under the age of 18 years increases 34% with each one-year increase in current age of the child (95% CI, 1.08-1.67, p-value=0.009), and decreases 45% with annual household income greater than $10,000 (95% CI, 0.35-0.88, p-value=0.013). Sibling birth order increased the likelihood of blood lead screening by 61% (95% CI, 1.04-2.48, p-value=0.032) for each successive child. Female children were rated by their care

Using community-level metrics to monitor the effects of marine protected areas on biodiversity.

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Soykan, Candan U; Lewison, Rebecca L

2015-06-01

Marine protected areas (MPAs) are used to protect species, communities, and their associated habitats, among other goals. Measuring MPA efficacy can be challenging, however, particularly when considering responses at the community level. We gathered 36 abundance and 14 biomass data sets on fish assemblages and used meta-analysis to evaluate the ability of 22 distinct community diversity metrics to detect differences in community structure between MPAs and nearby control sites. We also considered the effects of 6 covariates-MPA size and age, MPA size and age interaction, latitude, total species richness, and level of protection-on each metric. Some common metrics, such as species richness and Shannon diversity, did not differ consistently between MPA and control sites, whereas other metrics, such as total abundance and biomass, were consistently different across studies. Metric responses derived from the biomass data sets were more consistent than those based on the abundance data sets, suggesting that community-level biomass differs more predictably than abundance between MPA and control sites. Covariate analyses indicated that level of protection, latitude, MPA size, and the interaction between MPA size and age affect metric performance. These results highlight a handful of metrics, several of which are little known, that could be used to meet the increasing demand for community-level indicators of MPA effectiveness. © 2015 Society for Conservation Biology.

Community-level Moderators of a School-Based Childhood Sexual Assault Prevention Program

OpenAIRE

Morris, Matthew C.; Kouros, Chrystyna D.; Janecek, Kim; Freeman, Rachel; Mielock, Alyssa; Garber, Judy

2016-01-01

Childhood sexual abuse (CSA) is highly prevalent and associated with a wide variety of negative mental and physical health outcomes. School-based CSA education and prevention programs have shown promise, but it is unclear to what extent community-level characteristics are related to their effectiveness. The present cluster randomized controlled trial evaluated community-level moderators of the Safe@Last program compared to a waitlist control condition. Knowledge gains from pre- to post-interv...

Plant toxicity, adaptive herbivory, and plant community dynamics

Science.gov (United States)

Feng, Z.; Liu, R.; DeAngelis, D.L.; Bryant, J.P.; Kielland, K.; Stuart, Chapin F.; Swihart, R.K.

2009-01-01

We model effects of interspecific plant competition, herbivory, and a plant's toxic defenses against herbivores on vegetation dynamics. The model predicts that, when a generalist herbivore feeds in the absence of plant toxins, adaptive foraging generally increases the probability of coexistence of plant species populations, because the herbivore switches more of its effort to whichever plant species is more common and accessible. In contrast, toxin-determined selective herbivory can drive plant succession toward dominance by the more toxic species, as previously documented in boreal forests and prairies. When the toxin concentrations in different plant species are similar, but species have different toxins with nonadditive effects, herbivores tend to diversify foraging efforts to avoid high intakes of any one toxin. This diversification leads the herbivore to focus more feeding on the less common plant species. Thus, uncommon plants may experience depensatory mortality from herbivory, reducing local species diversity. The depensatory effect of herbivory may inhibit the invasion of other plant species that are more palatable or have different toxins. These predictions were tested and confirmed in the Alaskan boreal forest. ?? 2009 Springer Science+Business Media, LLC.

Interaction Networks: Generating High Level Hints Based on Network Community Clustering

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Eagle, Michael; Johnson, Matthew; Barnes, Tiffany

2012-01-01

We introduce a novel data structure, the Interaction Network, for representing interaction-data from open problem solving environment tutors. We show how using network community detecting techniques are used to identify sub-goals in problems in a logic tutor. We then use those community structures to generate high level hints between sub-goals.…

Hydrogen gas alleviates oxygen toxicity by reducing hydroxyl radical levels in PC12 cells.

Directory of Open Access Journals (Sweden)

Junchao Yu

Full Text Available Hyperbaric oxygen (HBO therapy through breathing oxygen at the pressure of above 1 atmosphere absolute (ATA is useful for varieties of clinical conditions, especially hypoxic-ischemic diseases. Because of generation of reactive oxygen species (ROS, breathing oxygen gas at high pressures can cause oxygen toxicity in the central nervous system, leading to multiple neurological dysfunction, which limits the use of HBO therapy. Studies have shown that Hydrogen gas (H2 can diminish oxidative stress and effectively reduce active ROS associated with diseases. However, the effect of H2 on ROS generated from HBO therapy remains unclear. In this study, we investigated the effect of H2 on ROS during HBO therapy using PC12 cells. PC12 cells cultured in medium were exposed to oxygen gas or mixed oxygen gas and H2 at 1 ATA or 5 ATA. Cells viability and oxidation products and ROS were determined. The data showed that H2 promoted the cell viability and inhibited the damage in the cell and mitochondria membrane, reduced the levels of lipid peroxidation and DNA oxidation, and selectively decreased the levels of •OH but not disturbing the levels of O2•-, H2O2, or NO• in PC12 cells during HBO therapy. These results indicated that H2 effectively reduced •OH, protected cells against oxygen toxicity resulting from HBO therapy, and had no effect on other ROS. Our data supported that H2 could be potentially used as an antioxidant during HBO therapy.

Use of Cellulolytic Marine Bacteria for Enzymatic Pretreatment in Microalgal Biogas Production

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Muñoz, Camilo; Hidalgo, Catalina; Zapata, Manuel; Jeison, David; Riquelme, Carlos

2014-01-01

In this study, we designed and evaluated a microalgal pretreatment method using cellulolytic bacteria that naturally degrades microalgae in their native habitat. Bacterial strains were isolated from each of two mollusk species in a medium containing 1% carboxymethyl cellulose agar. We selected nine bacterial strains that had endoglucanase activity: five strains from Mytilus chilensis, a Chilean mussel, and four strains from Mesodesma donacium, a clam found in the Southern Pacific. These strains were identified phylogenetically as belonging to the genera Aeromonas, Pseudomonas, Chryseobacterium, and Raoultella. The cellulase-producing capacities of these strains were characterized, and the degradation of cell walls in Botryococcus braunii and Nannochloropsis gaditana was tested with “whole-cell” cellulolytic experiments. Aeromonas bivalvium MA2, Raoultella ornithinolytica MA5, and Aeromonas salmonicida MC25 degraded B. braunii, and R. ornithinolytica MC3 and MA5 degraded N. gaditana. In addition, N. gaditana was pretreated with R. ornithinolytica strains MC3 and MA5 and was then subjected to an anaerobic digestion process, which increased the yield of methane by 140.32% and 158.68%, respectively, over that from nonpretreated microalgae. Therefore, a “whole-cell” cellulolytic pretreatment can increase the performance and efficiency of biogas production. PMID:24795376

Pollution-Induced Community Tolerance To Diagnose Hazardous Chemicals in Multiple Contaminated Aquatic Systems.

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Rotter, Stefanie; Gunold, Roman; Mothes, Sibylle; Paschke, Albrecht; Brack, Werner; Altenburger, Rolf; Schmitt-Jansen, Mechthild

2015-08-18

Aquatic ecosystems are often contaminated with large numbers of chemicals, which cannot be sufficiently addressed by chemical target analyses. Effect-directed analysis (EDA) enables the identification of toxicants in complex contaminated environmental samples. This study suggests pollution-induced community tolerance (PICT) as a confirmation tool for EDA to identify contaminants which actually impact on local communities. The effects of three phytotoxic compounds local periphyton communities, cultivated at a reference (R-site) and a polluted site (P-site), were assessed to confirm the findings of a former EDA study on sediments. The sensitivities of R- and P-communities to prometryn, tributyltin (TBT) and N-phenyl-2-naphthylamine (PNA) were quantified in short-term toxicity tests and exposure concentrations were determined. Prometryn and PNA concentrations were significantly higher at the P-site, whereas TBT concentrations were in the same range at both sites. Periphyton communities differed in biomass, but algal class composition and diatom diversity were similar. Community tolerance of P-communities was significantly enhanced for prometryn, but not for PNA and TBT, confirming site-specific effects on local periphyton for prometryn only. Thus, PICT enables in situ effect confirmation of phytotoxic compounds at the community level and seems to be suitable to support confirmation and enhance ecological realism of EDA.

Cd and Zn interactions and toxicity in ectomycorrhizal basidiomycetes in axenic culture

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Vinicius H. De Oliveira

2018-03-01

Full Text Available Background Metal contamination in soils affects both above- and belowground communities, including soil microorganisms. Ectomycorrhizal (ECM fungi are an important component in belowground community and tolerant strains have great potential in enhancing plant-based remediation techniques. We assessed cadmium and zinc toxicity in five ECM species in liquid media (Hebeloma subsaponaceum; H. cylindrosporum; H. crustuliniforme; Scleroderma sp.; Austroboletus occidentalis and investigated the potential of Zn to alleviate Cd toxicity. Due to highly divergent results reported in the literature, liquid and solid media were compared experimentally for the first time in terms of differential toxicity thresholds in Cd and Zn interactions. Methods A wide range of Cd and Zn concentrations were applied to ectomycorrhizal fungi in axenic cultures (in mg L−1: 0; 1; 3; 9; 27; 81; 243 for the Cd treatments, and 0; 1; 30; 90; 270; 810; 2,430 for Zn. Combined Zn and Cd treatments were also applied to H. subsaponaceum and Scleroderma sp. Dry weight was recorded after 30 days, and in case of solid medium treatments, radial growth was also measured. Results and Discussion All species were adversely affected by high levels of Cd and Zn, and A. occidentalis was the most sensitive, with considerable biomass decrease at 1 mg L−1 Cd, while Scleroderma sp. and H. subsaponaceum were the most tolerant, which are species commonly found in highly contaminated sites. Cd was generally 10 times more toxic than Zn, which may explain why Zn had little impact in alleviating Cd effects. In some cases, Cd and Zn interactions led to a synergistic toxicity, depending on the concentrations applied and type of media used. Increased tolerance patterns were detected in fungi grown in solid medium and may be the cause of divergent toxicity thresholds found in the literature. Furthermore, solid medium allows measuring radial growth/mycelial density as endpoints which are informative and in

Using the IRWQIGT Index to Determine Toxicity Levels in Groundwater Resources: A Case Study of Semnan Province

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Allahbakhsh Javid

2016-09-01

Full Text Available The objective of the present descriptive-analytic study was to estimate the toxicity level of the groundwater resources in the Province of Semnan using the IRWQIGT index and its zoning via GIS. The experiments were conducted over the period from October 2013 to October 2014during which time monthly samples were taken from the 41 wells that supply drinking water to the cities and towns in the Province. All the samples were subjected to lab analyses at Semnan Water and Wastewater Laboratory where such chemical parameters as Arsenic, Phenol, Mercury, Detergents, Cadmium, Lead, Chromium, Cyanide, Iron, Magnesium, and TPH were determined according to the procedures of Standard Methods (2008. The measuerments were subsequently used to calculate the groundwater toxicity level index (IRWQIGT. Finally, a zoning map of the IRWQIGT index for Semnan Province was prepared using GIS. Results showed that the IRWQIGT index in Semnan Province ranged between 96.54 and 98.2, indicating an excellent water quality. The lowest (96.585 and highest (98.076 values of IRWQIGT were recorded in the cities of Sorkheh and Mahdishahr, respectively, and that the values for all the parameters were in the standard range. These results indicate that water of excellent quality is available in all the cities in the province so that no toxicity treatment is required.

Albumin levels and cause-specific mortality in community-dwelling older adults.

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Wu, Chen-Yi; Hu, Hsiao-Yun; Huang, Nicole; Chou, Yi-Chang; Li, Chung-Pin; Chou, Yiing-Jenq

2018-04-09

To investigate the association between serum albumin levels and cause-specific mortality among community-dwelling older adults. This cohort study was based on data obtained from the government-sponsored Annual Geriatric Health Examination Program for the older adults in Taipei City between 2006 and 2010. The study sample consisted of 77,531 community-dwelling Taipei citizens (≥65 years old). Mortality was determined by matching the participants' medical records with national death files. Serum albumin levels were categorized into dwelling older adults had a mean albumin level of 4.3 g/dL, which significantly reduced by age. Compared to albumin levels ≥4.4 g/dL, mildly low albumin levels (4.2-4.3 g/dL) were associated with an increased mortality risk (hazard ratio [HR]: 1.16, 95% confidence interval [CI]: 1.05-1.28 for all-cause mortality), and albumin levels dwelling older adults, and mortality risk increased as the albumin level decreased. Copyright © 2017. Published by Elsevier Inc.

Individual-level socioeconomic status and community-level inequality as determinants of stigma towards persons living with HIV who inject drugs in Thai Nguyen, Vietnam

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Lim, Travis; Zelaya, Carla; Latkin, Carl; Quan, Vu Minh; Frangakis, Constantine; Ha, Tran Viet; Minh, Nguyen Le; Go, Vivian

2013-01-01

Introduction HIV infection may be affected by multiple complex socioeconomic status (SES) factors, especially individual socioeconomic disadvantage and community-level inequality. At the same time, stigma towards HIV and marginalized groups has exacerbated persistent concentrated epidemics among key populations, such as persons who inject drugs (PWID) in Vietnam. Stigma researchers argue that stigma fundamentally depends on the existence of economic power differences in a community. In rapidly growing economies like Vietnam, the increasing gap in income and education levels, as well as an individual's absolute income and education, may create social conditions that facilitate stigma related to injecting drug use and HIV. Methods A cross-sectional baseline survey assessing different types of stigma and key socioeconomic characteristics was administered to 1674 PWID and 1349 community members living in physical proximity throughout the 32 communes in Thai Nguyen province, Vietnam. We created four stigma scales, including HIV-related and drug-related stigma reported by both PWID and community members. We then used ecologic Spearman's correlation, ordinary least-squares regression and multi-level generalized estimating equations to examine community-level inequality associations, individual-level SES associations and multi-level SES associations with different types of stigma, respectively. Results There was little urban–rural difference in stigma among communes. Higher income inequality was marginally associated with drug-related stigma reported by community members (p=0.087), and higher education inequality was significantly associated with higher HIV-related stigma reported by both PWID and community members (pstigma (HIV and drug related) reported by both PWID and community members. Part-time employed PWID reported more experiences and perceptions of drug-related stigma, while conversely unemployed community members reported enacting lower drug-related stigma

Assessing condition of macroinvertebrate communities and bed sediment toxicity in the Rochester Embayment Area of Concern, New York, USA

Science.gov (United States)

Duffy, Brian; George, Scott D.; Baldigo, Barry P.; Smith, Alexander J.

2017-01-01

The United States and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement in 1972. The lowest reach of the Genesee River and the Rochester Embayment on Lake Ontario between Bogus Point and Nine Mile Point, including Braddock Bay, were designated as an Area of Concern (AOC) due to effects of contaminated sediments and physical disturbance on several beneficial uses. Following sediment remedial efforts and with conditions improving in the AOC, the present study was conducted to reevaluate the status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate community assessments and 10-day Chironomus dilutus bioassays were used to test the hypotheses that sediments within the AOC were no more toxic than sediments from surrounding reference areas. The study was separated into three discrete systems (Genesee River, Lake Ontario, and Braddock Bay) and non-parametric analyses determined that a multimetric index of benthic macroinvertebrate community integrity was significantly higher at AOC sites compared to reference sites on the Genesee River and in Braddock Bay while AOC and reference sites on Lake Ontario did not differ significantly. Survival and growth of C. dilutus were also similar between AOC and reference sites for each system with the exception of significantly higher growth at reference sites on Lake Ontario. Results generally indicated that the condition of benthos and toxicity of sediment of the Rochester Embayment AOC are similar to or better than that in the surrounding area.

Biofilm composition in the Olt River (Romania) reservoirs impacted by a chlor-alkali production plant.

Science.gov (United States)

Dranguet, P; Cosio, C; Le Faucheur, S; Hug Peter, D; Loizeau, J-L; Ungureanu, V-Gh; Slaveykova, V I

2017-05-24

Freshwater biofilms can be useful indicators of water quality and offer the possibility to assess contaminant effects at the community level. The present field study examines the effects of chlor-alkali plant effluents on the community composition of biofilms grown in the Olt River (Romania) reservoirs. The relationship between ambient water quality variables and community composition alterations was explored. Amplicon sequencing revealed a significant modification of the composition of microalgal, bacterial and fungal communities in the biofilms collected in the impacted reservoirs in comparison with those living in the uncontaminated control reservoir. The abundance corrected Simpson index showed lower richness and diversity in biofilms collected in the impacted reservoirs than in the control reservoir. The biofilm bacterial communities of the impacted reservoirs were characterized by the contaminant-tolerant Cyanobacteria and Bacteroidetes, whereas microalgal communities were predominantly composed of Bacillariophyta and fungal communities of Lecanoromycetes and Paraglomycetes. A principal component analysis revealed that major contaminants present in the waste water of the chlor-alkali production plant, i.e. Na + , Ca 2+ , Cl - and Hg, were correlated with the alteration of biofilm community composition in the impacted reservoirs. However, the biofilm composition was also influenced by water quality variables such as NO 3 - , SO 4 2- , DOC and Zn from unknown sources. The results of the present study imply that, even when below the environmental quality standards, typical contaminants of chlor-alkali plant releases may affect biofilm composition and that their impacts on the microbial biodiversity might be currently overlooked.

Identifying ozone-sensitive communities of (semi-)natural vegetation suitable for mapping exceedance of critical levels

International Nuclear Information System (INIS)

Mills, G.; Hayes, F.; Jones, M.L.M.; Cinderby, S.

2007-01-01

Using published data on the responses of individual species to ozone, 54 EUNIS (European Nature Information System) level 4 communities with six or more ozone-sensitive species (%OS) and c. 20% or more species tested for ozone sensitivity, were identified as potentially ozone-sensitive. The largest number of these communities (23) was associated with Grasslands, with Heathland, scrub and tundra, and Mires, bogs and fens having the next highest representation at 11 and 8 level 4 communities each respectively. Within the grasslands classification, E4 (Alpine and sub-alpine grasslands), E5 (Woodland fringes and clearings) and E1 (Dry grasslands) were the most sensitive with 68.1, 51.6 and 48.6%OS respectively. It is feasible to map the land-cover for these and other communities at level 2, but it may not be currently possible to map the land-cover for all communities identified to be ozone-sensitive at levels 3 and 4. - Grassland communities such as alpine and sub-alpine grasslands have the highest potential sensitivity ozone, based on the responses of their component species

Investigating influences on current community pharmacy practice at micro, meso, and macro levels.

Science.gov (United States)

Hermansyah, Andi; Sainsbury, Erica; Krass, Ines

The nature of Australian community pharmacy is continually evolving, raising the need to explore the current situation in order to understand the potential impact of any changes. Although community pharmacy has the potential to play a greater role in health care, it is currently not meeting this potential. To investigate the nature of the contemporary practice of community pharmacy in Australia and examine the potential missed opportunities for role expansion in health care. In-depth semi-structured interviews with a wide-range of key stakeholders within and beyond community pharmacy circles were conducted. Interviews were audio-recorded, transcribed verbatim and analyzed for emerging themes. Twenty-seven key informants across Eastern half of Australia were interviewed between December 2014 and August 2015. Several key elements of the current situation representing the social, economic and policy context of community pharmacy have been identified. These elements operate interdependently, influence micro, meso and macro levels of community pharmacy operation and are changing in the current climate. Community pharmacy has untapped potential in primary health care, but it has been slow to change to meet opportunities available in the current situation. As the current situation is complex, interrelated and dynamic with often unintended and unpredictable consequences, this paper suggests that policy makers to consider the micro, meso and macro levels of community pharmacy operation when making significant policy changes. The framework proposed in this study can be a helpful tool to analyze the processes operating at these three levels and their influences on practice. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparing probabilistic and descriptive analyses of time–dose–toxicity relationship for determining no-observed-adverse-effect level in drug development

International Nuclear Information System (INIS)

Glatard, Anaïs; Berges, Aliénor; Sahota, Tarjinder; Ambery, Claire; Osborne, Jan; Smith, Randall; Hénin, Emilie; Chen, Chao

2015-01-01

The no-observed-adverse-effect level (NOAEL) of a drug defined from animal studies is important for inferring a maximal safe dose in human. However, several issues are associated with its concept, determination and application. It is confined to the actual doses used in the study; becomes lower with increasing sample size or dose levels; and reflects the risk level seen in the experiment rather than what may be relevant for human. We explored a pharmacometric approach in an attempt to address these issues. We first used simulation to examine the behaviour of the NOAEL values as determined by current common practice; and then fitted the probability of toxicity as a function of treatment duration and dose to data collected from all applicable toxicology studies of a test compound. Our investigation was in the context of an irreversible toxicity that is detected at the end of the study. Simulations illustrated NOAEL's dependency on experimental factors such as dose and sample size, as well as the underlying uncertainty. Modelling the probability as a continuous function of treatment duration and dose simultaneously to data from multiple studies allowed the estimation of the dose, along with its confidence interval, for a maximal risk level that might be deemed as acceptable for human. The model-based data integration also reconciled between-study inconsistency and explicitly provided maximised estimation confidence. Such alternative NOAEL determination method should be explored for its more efficient data use, more quantifiable insight to toxic doses, and the potential for more relevant animal-to-human translation. - Highlights: • Simulations revealed issues with NOAEL concept, determination and application. • Probabilistic modelling was used to address these issues. • The model integrated time-dose-toxicity data from multiple studies. • The approach uses data efficiently and may allow more meaningful human translation.

Comparing probabilistic and descriptive analyses of time–dose–toxicity relationship for determining no-observed-adverse-effect level in drug development

Energy Technology Data Exchange (ETDEWEB)

Glatard, Anaïs; Berges, Aliénor; Sahota, Tarjinder; Ambery, Claire [Clinical Pharmacology Modelling and Simulation, GlaxoSmithKline, 1 Iron Bridge Road, Uxbridge, UB11 1BT London (United Kingdom); Osborne, Jan [Non-Clinical Safety Projects, GlaxoSmithKline, Ware (United Kingdom); Smith, Randall [Computational Toxicology, GlaxoSmithKline, Upper Merion (United States); Hénin, Emilie [UMR 5558 Laboratoire Biométrie et de Biologie Evolutive, Equipe EMET (Evaluation et Modélisation des Effets Thérapeutiques), Université Claude Bernard Lyon1, Service de Pharmacologie Clinique et Essais Thérapeutiques, Hospices Civils de Lyon, Lyon (France); Chen, Chao, E-mail: chao.c.chen@gsk.com [Clinical Pharmacology Modelling and Simulation, GlaxoSmithKline, 1 Iron Bridge Road, Uxbridge, UB11 1BT London (United Kingdom)

2015-10-15

The no-observed-adverse-effect level (NOAEL) of a drug defined from animal studies is important for inferring a maximal safe dose in human. However, several issues are associated with its concept, determination and application. It is confined to the actual doses used in the study; becomes lower with increasing sample size or dose levels; and reflects the risk level seen in the experiment rather than what may be relevant for human. We explored a pharmacometric approach in an attempt to address these issues. We first used simulation to examine the behaviour of the NOAEL values as determined by current common practice; and then fitted the probability of toxicity as a function of treatment duration and dose to data collected from all applicable toxicology studies of a test compound. Our investigation was in the context of an irreversible toxicity that is detected at the end of the study. Simulations illustrated NOAEL's dependency on experimental factors such as dose and sample size, as well as the underlying uncertainty. Modelling the probability as a continuous function of treatment duration and dose simultaneously to data from multiple studies allowed the estimation of the dose, along with its confidence interval, for a maximal risk level that might be deemed as acceptable for human. The model-based data integration also reconciled between-study inconsistency and explicitly provided maximised estimation confidence. Such alternative NOAEL determination method should be explored for its more efficient data use, more quantifiable insight to toxic doses, and the potential for more relevant animal-to-human translation. - Highlights: • Simulations revealed issues with NOAEL concept, determination and application. • Probabilistic modelling was used to address these issues. • The model integrated time-dose-toxicity data from multiple studies. • The approach uses data efficiently and may allow more meaningful human translation.

Stroke survivors’ levels of community reintegration, quality of life, satisfaction with the physiotherapy services and the level of caregiver strain at community health centres within the Johannesburg area

Directory of Open Access Journals (Sweden)

Adrian Kusambiza-Kiingi

2017-03-01

Full Text Available Background: Stroke survivors are discharged home before they are functionally independent and return home with activity limitations that would not be manageable without a caregiver. Aim: To determine stroke survivors’ levels of community reintegration, quality of life (QOL, satisfaction with the physiotherapy services and the level of caregiver strain at community health centres within the Johannesburg area. Method: This was a cross-sectional study using the following outcome measures: Maleka Stroke Community Reintegration Measure, Stroke-specific quality of life scale, Caregiver strain index and Physical therapy patient satisfaction questionnaire. Results: A total of 108 stroke survivors and 45 caregivers participated in this study. The average age of the stroke survivors was 54 years (standard deviation = 12.73 and 58% (n = 62 had moderate to full community reintegration. They were happy with physiotherapy services but not with parking availability and cost of services. The QOL was poor with the lowest scores for energy and highest scores for vision and language domains. Twenty five (55% caregivers were strained. A positive correlation was found between community reintegration and satisfaction with services (r = 0.27, p < 0.0001 and QOL (r = 0.51, p < 0.0001. A negative correlation was found between community reintegration and caregiver strain (r = -0.37, p < 0.0001. Conclusion: Most stroke survivors are reintegrated into their communities except in the areas of work and education and have poor QOL and most of their caregivers are strained; however, they are satisfied with physiotherapy services.

Assessment of the levels of potentially toxic substances around a transect of anthrosols in Aqaba shoreline, Jordan

Science.gov (United States)

Wahsha, Mohammad; Al-Rousan, Saber; Al-Jawasreh, Raid

2016-04-01

Soils are the major sink for potentially toxic substances (PTSs) such as heavy metals released into the environment by emissions from the quickly increasing of human impact including industrial mine tailings, disposal of high metal wastes, land misuse, wastewater irrigation, spillage of petrochemicals, and atmospheric deposition. The present study concerns the properties variability and soil biological health status in abandoned salt transportation port site in the Jordanian coast of the Gulf of Aqaba, Red Sea. Seven sites were selected according to different morphological and pedological conditions, anthropogenic impact and the same climate conditions. Successively, all locations were sampled for topsoil in the period between spring-summer 2014. Field observations as well as laboratory analysis including heavy metal concentrations (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn); soil chemo-physical parameters (pH, soil dry mass, carbonate, water holding, organic carbon content, soil particle size distribution), and quality of soil's biological community were determined. The anthropogenic influence related to former port activity on soils of the studied area is evident. Soils in the studied area site are highly contaminated by PTSs, mainly Cu and Zn, by 648, 298.6 mgKg-1respectively. Former activities proved to affect the microarthropods community altering both quantity and quality of soil and the chemo-physical structure of the microhabitats. The evaluation of soil biological quality index (QBS-ar) of the surface horizons from the study area is demonstrated that the area is "sufferings" since it is affected by PTSs contamination resulting in a failure in the ecological success of secondary recolonization after abandonment. However, there is an increasing need for further research in the soils of Aqaba focusing on soil health management , combining QBS-ar index with soil chemo-physical properties. Key words: Potentially Toxic Substances, Heavy Metals, Soil Quality.

Integrating the fish embryo toxicity test as triad element for sediment toxicity assessment based on the water framework directive approach

Energy Technology Data Exchange (ETDEWEB)

Bartzke, Mariana [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Dept. Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Leipzig (Germany); Delov, Vera [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Ecotoxicology, Fraunhofer Inst. for Molecular Biology and Applied Ecology IME, Aachen (Germany); Stahlschmidt-Allner, Petra; Allner, Bernhard [Gobio GmbH, Aarbergen/Kettenbach (Germany); Oehlmann, Joerg [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany)

2010-04-15

Purpose: The objective of this study was to complement analyses according to the European Union Water Framework Directive (WFD) with a sediment toxicity analysis as part of an integrated river assessment. To this end, Hessian water courses were analyzed using the sediment quality triad concept according to Chapman with chemical analyses, in situ effect evaluations, and ecotoxicological assessments. For the ecotoxicological assessment (fish embryo toxicity test with Danio rerio), a new evaluation scheme was developed, the fish teratogenicity index (FTI), that allows for a classification of sediments into ecological quality classes compliant to the WFD. Materials and methods sediment and macrozoobenthos samples were taken from tributaries of the rivers Fulda and Lahn. Sediments were characterized regarding particle size, carbon, heavy metals, and polyaromatic hydrocarbon content. Macroinvertebrate samples were taken via multi-habitat sampling. The fish embryo toxicity test with D. rerio was conducted as a contact assay on the basis of DIN 38415-6. Results and discussion The integrated assessment indicated a significant influence of heavy metals and carbon content on macroinvertebrate communities. The bioaccessibility of sediment pollutants were clearly demonstrated by the FTI, which showed a wide range of adverse effects. A significant linear relationship between metals and the FTI was detected. However, there was no statistically significant evidence that macroinvertebrate communities were affected by the hydromorphological quality clements at the sampling sites. Conclusions The new scheme for the assessment of fish embryo toxicity test was successfully applied. The results suggest that sediment compounds impact macroinvertebrate communities and early development of fish. It demonstrates that the quality of sediments should be evaluated on a routine basis as part of an integrated river assessment. (orig.)

Occupational and environmental hazard assessments for the isolation, purification and toxicity testing of cyanobacterial toxins

Directory of Open Access Journals (Sweden)

Wickramasinghe Wasantha A

2009-11-01

Full Text Available Abstract Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities.

Occupational and environmental hazard assessments for the isolation, purification and toxicity testing of cyanobacterial toxins

Science.gov (United States)

2009-01-01

Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities. PMID:19925679

Is the contribution of community forest users financially efficient? A household level benefit-cost analysis of community forest management in Nepal

Directory of Open Access Journals (Sweden)

Rajesh Kumar Rai

2016-02-01

Full Text Available Community forestry in Nepal is considered an exemplary forest management regime. However, the economics behind managing a community forest is not fully studied. This study examines whether the benefits generated from community forest management justify the contributions of forest users. The study is based on a survey of community forest users in Chitwan, Nepal. A household level benefit-cost analysis was performed to quantify and compare the costs and benefits from community forest management. Only direct benefits were included in the analysis. The study shows that older forest user groups derive more benefits to households compared to more recently established ones. The extent of timber harvesting also substantially influences the size of the household benefits. In addition, redistribution of benefits at the household level, in terms of income generating activities and payment for involvement in forest management activities, also enhances household benefits. Sensitivity analysis suggests that the current practice of community forest management enhances the welfare of rural households in this subsistence community. However, this finding is sensitive to assumptions regarding the opportunity cost of time. The study also found that the household costs of community forest management depend upon two factors – the area of community forest and the size of the forest area relative to the number of households.

Association between individual-level and community-level socio-economic status and blood pressure among Inuit in Greenland

DEFF Research Database (Denmark)

Riva, Mylène; Larsen, C. V. L.; Bjerregaard, Peter

2016-01-01

and older participated. Blood pressure is measured using an automatic device, according to standardized protocol. Individual SES is measured by education. Community socio-economic conditions are measured using combined information on average disposable household income and settlement type. Results....... Education was not significantly associated with blood pressure. There was an inverse U-shape association between community socio-economic conditions and blood pressure with significantly lower SBP and DBP among participants living in remote traditional villages characterized by lower average disposable...... household income and in affluent more urbanized towns. Sex-stratified analyses demonstrate the salience of community conditions for men. Conclusions. The association observed between blood pressure and community-level socio-economic conditions suggests that public health and social policies, programmes...

Effect of nutritional state on Hsp60 levels in the rotifer Brachionus plicatilis following toxicant exposure.

Science.gov (United States)

Wheelock, C E; Baumgartner, T A; Newman, J W; Wolfe, M F; Tjeerdema, R S

2002-11-13

The nutritional state of an organism can affect the results of toxicity testing. Here we exemplified this fact by examining the effect of nutritional deprivation on heat shock protein 60 (hsp60) production in the rotifer Brachionus plicatilis following exposure to two proven inducers of hsp60, a water-accommodated fraction of crude oil (WAF) and a dispersed oil preparation (DO). Both DO and WAF exposures of unfed rotifers resulted in significantly greater hsp60 levels than that of fed DO and WAF exposed rotifers at 8 h: 870 and 3100% of control, respectively. Results clearly demonstrate that a poor nutritional state potentiates stress protein induction upon exposure to water-soluble petroleum products. It is therefore critical to define the organismal nutritional status when reporting toxic responses. Copyright 2002 Elsevier Science B.V.

Anaerobic toxicity of cationic silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Gitipour, Alireza; Thiel, Stephen W. [Biomedical, Chemical, and Environmental Engineering, University of Cincinnati, Cincinnati, OH (United States); Scheckel, Kirk G. [USEPA, Office of Research and Development, Cincinnati, OH (United States); Tolaymat, Thabet, E-mail: tolaymat.thabet@epa.gov [USEPA, Office of Research and Development, Cincinnati, OH (United States)

2016-07-01

The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag{sup +} under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged polyvinylpyrrolidone coated AgNPs (PVP-AgNPs) and (3) positively charged branched polyethyleneimine coated AgNPs (BPEI-AgNPs). The AgNPs investigated in this experiment were similar in size (10–15 nm), spherical in shape, but varied in surface charge which ranged from highly negative to highly positive. While, at AgNPs concentrations lower than 5 mg L{sup −1}, the anaerobic decomposition process was not influenced by the presence of the nanoparticles, there was an observed impact on the diversity of the microbial community. At elevated concentrations (100 mg L{sup −1} as silver), only the cationic BPEI-AgNPs demonstrated toxicity similar in magnitude to that of Ag{sup +}. Both citrate and PVP-AgNPs did not exhibit toxicity at the 100 mg L{sup −1} as measured by biogas evolution. These findings further indicate the varying modes of action for nanoparticle toxicity and represent one of the few studies that evaluate end-of-life management concerns with regards to the increasing use of nanomaterials in our everyday life. These findings also highlight some of the concerns with a one size fits all approach to the evaluation of environmental health and safety concerns associated with the use of nanoparticles. - Highlights: • At concentrations -1 the anaerobic decomposition process was not impacted. • An impact on the microbial community at concentrations -1 were observed. • At high concentrations (100 mg L{sup −1}), the cationic BPEI-AgNPs demonstrated toxicity. • Toxicity was demonstrated without the presence of oxidative dissolution of silver. • A one size fits all approach for the evaluation of NPs may not be accurate.

Application of Fungicides and Microalgal Phenolic Extracts for the Direct Control of Fumonisin Contamination in Maize.

Science.gov (United States)

Scaglioni, Priscila Tessmer; Blandino, Massimo; Scarpino, Valentina; Giordano, Debora; Testa, Giulio; Badiale-Furlong, Eliana

2018-05-16

Fungicides and, for the first time, microalgal phenolic extracts (MPE) from Spirulina sp. and Nannochloropsis sp. were applied on maize culture media under field conditions to evaluate their ability to minimize Fusarium species development and fumonisin production. An in vitro assay against F. verticillioides was carried out using maize grains as the culture medium. An open-field experiment was carried out in Northwest Italy under natural infection conditions. The compared treatments were factorial combinations of two insecticide treatments (an untreated control and pyrethroid, used against European Corn Borer), four antifungal treatments (an untreated control, MPE from Spirulina sp., MPE from Nannochloropsis sp., and a synthetic fungicide), and two timings of the application of the antifungal compounds (at maize flowering and at the milk stage). The MPE compounds were capable of inhibiting fumonisin production in vitro more efficiently than tebuconazole. Insecticide application reduced the infection by Fusarium species and subsequent fumonisin contamination. However, fumonisins in maize fields were not significantly controlled by either fungicide or MPE application.

Studies on the effects on growth and antioxidant responses of two marine microalgal species to uniconazole

Science.gov (United States)

Mei, Xueqiao; Zheng, Kang; Wang, Lingdong; Li, Yantuan

2014-10-01

Uniconazole, as a plant growth retardant, can enhance stress tolerance in plants, possibly because of improved antioxidation defense mechanisms with higher activities of superoxide dismutase (SOD) and peroxidase (POD) enzymes that retard lipid peroxidation and membrane deterioration. These years much attention has been focused on the responses of antioxidant system in plants to uniconazole stress, but such studies on aquatic organism are very few. Moreover, no information is available on growth and antioxidant response in marine microalgae to uniconazole. In this paper, the growth and antioxidant responses of two marine microalgal species, Platymonas helgolandica and Pavlova viridis, at six uniconazole concentrations (0-15 mg L-1) were investigated. The results demonstrated that 3 mg L-1 uniconazole could increase significantly chlorophyll a and carbohydrate contents of P. helgolandica ( P enzymes, superoxide dismutase (SOD) and catalase (CAT) were enhanced remarkably at low concentrations of uniconazole. However, significant reduction of SOD and CAT activities was observed at higher concentrations of uniconazole.

Toxicity of road salt to Nova Scotia amphibians

International Nuclear Information System (INIS)

Collins, Sara J.; Russell, Ronald W.

2009-01-01

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC 50 ) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. - Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands

Community Level Risk Factors for Maternal Mortality in Madagascar

African Journals Online (AJOL)

AJRH Managing Editor

This paper explores the effect of risk and socioeconomic factors on maternal mortality at the ... to study maternal mortality, however, studying maternal mortality at the community ... causes of maternal mortality at the country level in ... Antananarivo, the capital city of Madagascar, .... cyclones, and crime can be associated with.

Association between Urine Fluoride and Dental Fluorosis as a Toxicity Factor in a Rural Community in the State of San Luis Potosi

OpenAIRE

Jarquín-Yañez, Lizet; Mejía-Saavedra, José de Jesús; Molina-Frechero, Nelly; Gaona, Enrique; Rocha-Amador, Diana Olivia; López-Guzmán, Olga Dania; Bologna-Molina, Ronell

2015-01-01

Objective. The aim of this study is to investigate urine fluoride concentration as a toxicity factor in a rural community in the state of San Luis Potosi, Mexico. Materials and Methods. A sample of 111 children exposed to high concentrations of fluoride in drinking water (4.13?mg/L) was evaluated. Fluoride exposure was determined by measuring urine fluoride concentration using the potentiometric method with an ion selective electrode. The diagnosis of dental fluorosis was performed by clinica...

Levels of toxic elements in soils of abandoned waste dump site ...

African Journals Online (AJOL)

Of all the five toxic elements studied, the highest mean concentration (mg/kg) of 133.74±10.60 was recorded for Pb followed by Cr (22.27±3.03), Ni (8.14±0.33) and As (5.97±0.32) in the soils while the least mean concentration of 1.64±0.11 was recorded for Cd. The toxic elements were examined for dependency upon some ...

Individual-level socioeconomic status and community-level inequality as determinants of stigma towards persons living with HIV who inject drugs in Thai Nguyen, Vietnam.

Science.gov (United States)

Lim, Travis; Zelaya, Carla; Latkin, Carl; Quan, Vu Minh; Frangakis, Constantine; Ha, Tran Viet; Minh, Nguyen Le; Go, Vivian

2013-11-13

HIV infection may be affected by multiple complex socioeconomic status (SES) factors, especially individual socioeconomic disadvantage and community-level inequality. At the same time, stigma towards HIV and marginalized groups has exacerbated persistent concentrated epidemics among key populations, such as persons who inject drugs (PWID) in Vietnam. Stigma researchers argue that stigma fundamentally depends on the existence of economic power differences in a community. In rapidly growing economies like Vietnam, the increasing gap in income and education levels, as well as an individual's absolute income and education, may create social conditions that facilitate stigma related to injecting drug use and HIV. A cross-sectional baseline survey assessing different types of stigma and key socioeconomic characteristics was administered to 1674 PWID and 1349 community members living in physical proximity throughout the 32 communes in Thai Nguyen province, Vietnam. We created four stigma scales, including HIV-related and drug-related stigma reported by both PWID and community members. We then used ecologic Spearman's correlation, ordinary least-squares regression and multi-level generalized estimating equations to examine community-level inequality associations, individual-level SES associations and multi-level SES associations with different types of stigma, respectively. There was little urban-rural difference in stigma among communes. Higher income inequality was marginally associated with drug-related stigma reported by community members (p=0.087), and higher education inequality was significantly associated with higher HIV-related stigma reported by both PWID and community members (pinequality and HIV-related stigma is superseded by the effect of individual-level education. The results of the study confirm that socioeconomic factors at both the individual level and community level affect different types of stigma in different ways. Attention should be paid to these

The levels of Community Involvement in Health (CIH: a case of rural and urban communities in KwaZulu-Natal

Directory of Open Access Journals (Sweden)

G.G. Mchunu

2009-09-01

Full Text Available The study aimed to describe the practice of community involvement in health programmes.The study therefore explored the nature and practice of community involvementin health programmes in the two communities in KwaZulu Natal. Thestudy was guided by the conceptual framework adapted from Amstein’s,( 1969 Ladderof Citizen Participation. This framework shows different levels and steps in communityparticipation. A case study method was used to conduct the study. The twocases were one urban based and one rural based community health centers in theIlembe health district, in Kwa Zulu Natal. A sample of 31 persons participated in thestudy. The sample comprised 8 registered nurses, 2 enrolled nurses 13 communitymembers and 8 community health workers. Data was collected using structured individualinterviews and focus group interviews, and was guided by the case protocol.Community involvement in health largely depended on the type of community, withrural community members being in charge of their health projects and urban communitymembers helping each other as neighbours in times of need.

Toxicity of nickel to soil microbial community with and without the presence of its mineral collectors-a calorimetric approach.

Science.gov (United States)

Bararunyeretse, Prudence; Ji, Hongbing; Yao, Jun

2017-06-01

The toxicity of nickel and three of its main collectors, sodium isopropyl xanthate (SIPX), sodium ethyl xanthate (SEX), and potassium ethyl xanthate (PEX) to soil microbial activity, was analyzed, individually and as a binary combination of nickel and each of the collectors. The investigation was performed through the microcalorimetric analysis method. For the single chemicals, all power-time curves exhibited lag, exponential, stationary, and death phases of microbial growth. Different parameters exhibited a significant adverse effect of the analyzed chemicals on soil microbial activity, with a positive relationship between the inhibitory ratio and the chemical dose (p soil in the case of Ni while for the mineral collectors, only 5 μg g -1 soil and 50 μg g -1 soil induced a peak power reduction level of over 35 and 50%, respectively, in general. The inhibitory ratio ranged in the following order: PEX > SEX > SIPX > Ni. Similar behavior was observed with the mixture toxicity whose inhibitory ratio substantially decreased (maximum decrease of 38.35%) and slightly increased (maximum increase of 15.34%), in comparison with the single toxicity of mineral collectors and nickel, respectively. The inhibitory ratio of the mixture toxicity was positively correlated (p toxic effects are those of mixtures containing SIPX and PEX, respectively.

Assessment of the toxicity level of gamma-irradiated snake (Naja naja oxiana) venom by photoacoustic spectroscopy

International Nuclear Information System (INIS)

Vidyasagar, P.B.; Pal, Saumen

1991-01-01

Immunization is the only answer to the challenge of the diseases for which it is extremely difficult to institute timely and proper treatment following the inset. Various antigenic agents responsible for such diseases are used for the purpose of immunization to overcome this difficulty. To make safe use of the antigens it is required to reduce their toxicity level keeping the antigenicity intact and develop a suitable way to detect it. To ensure this, toxoids are produced from the toxic antigens by using different physical and chemical methods. Snake venoms are some important antigens which deserve more attention to be used for immunization because bites by poisonous snakes require instant treatment which is difficult to install. Toxoids used in the present study were produced by irradiating oxus cobra (Naja naja oxiana) venom under cobalt-60 gamma-ray source. The toxocity level of thus produced venom toxoid was assessed by photoacoustic (PA) spectroscopy. In support of the PA observations, optical absorption and fluorescence spectra of the venom in solution were also studied. Percentile change in PA signal intensity was taken as the parameter for toxocity level which was then correlated to the percentile residual toxocity of the venom obtained by direct method of injecting the venom in mice. Efforts were also made to find out the possible effects of the radiation on the venom. (author). 29 refs., 7 figs

Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

Science.gov (United States)

Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

2016-01-01

Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions. PMID:26735689

Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

Science.gov (United States)

Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

2016-01-01

Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

Directory of Open Access Journals (Sweden)

Mo-Zhu Wang

Full Text Available Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

Home visiting and the biology of toxic stress: opportunities to address early childhood adversity.

Science.gov (United States)

Garner, Andrew S

2013-11-01

Home visiting is an important mechanism for minimizing the lifelong effects of early childhood adversity. To do so, it must be informed by the biology of early brain and child development. Advances in neuroscience, epigenetics, and the physiology of stress are revealing the biological mechanisms underlying well-established associations between early childhood adversity and suboptimal life-course trajectories. Left unchecked, mediators of physiologic stress become toxic, alter both genome and brain, and lead to a vicious cycle of chronic stress. This so-called "toxic stress" results a wide array of behavioral attempts to blunt the stress response, a process known as "behavioral allostasis." Although behaviors like smoking, overeating, promiscuity, and substance abuse decrease stress transiently, over time they become maladaptive and result in the unhealthy lifestyles and noncommunicable diseases that are the leading causes of morbidity and mortality. The biology of toxic stress and the concept of behavioral allostasis shed new light on the developmental origins of lifelong disease and highlight opportunities for early intervention and prevention. Future efforts to minimize the effects of childhood adversity should focus on expanding the capacity of caregivers and communities to promote (1) the safe, stable, and nurturing relationships that buffer toxic stress, and (2) the rudimentary but foundational social-emotional, language, and cognitive skills needed to develop healthy, adaptive coping skills. Building these critical caregiver and community capacities will require a public health approach with unprecedented levels of collaboration and coordination between the healthcare, childcare, early education, early intervention, and home visiting sectors.

Isonychia spp. and macroinvertebrate community responses to stressors in streams utilizing the benthic in situ toxicity identification evaluation (BiTIE) method

International Nuclear Information System (INIS)

Custer, Kevin W.; Burton, G. Allen

2008-01-01

Exposures of caged organisms in situ have proven to be a useful way to improve exposure realism and link to stressor effects in aquatic assessments of hazard or risk. A novel cage system, the benthic in situ toxicity identification evaluation (BiTIE), was developed for benthic macroinvertebrates (surrogate species, resident populations and communities) to separate low and high flow effects, and major chemical classes of stressors in streams. Three resin types were used to separate the chemical stressors in the streams Honey Creek and Little Beavercreek, Ohio, USA: Dowex TM Optipore TM (non-polar organics), zeolite (ammonia), and polywool (control). Isonychia spp. sensitivity was compared to Chironomus tentans, and no significant differences were found (p > 0.05). Isonychia spp. growth (length) showed a stressor response in the zeolite treatments, and community testing revealed improved metric responses in the Dowex TM treatments. The BiTIE chamber system demonstrated stressor-response relationships using sublethal and multimetric endpoints. - Use of an indigenous aquatic insect and benthic macroinvertebrate communities allows for discerning the stressors in low and high flows with an in situ TIE approach

Relationships among exceedences of metals criteria, the results of ambient bioassays, and community metrics in mining-impacted streams.

Science.gov (United States)

Griffith, Michael B; Lazorchak, James M; Herlihy, Alan T

2004-07-01

If bioassessments are to help diagnose the specific environmental stressors affecting streams, a better understanding is needed of the relationships between community metrics and ambient criteria or ambient bioassays. However, this relationship is not simple, because metrics assess responses at the community level of biological organization, while ambient criteria and ambient bioassays assess or are based on responses at the individual level. For metals, the relationship is further complicated by the influence of other chemical variables, such as hardness, on their bioavailability and toxicity. In 1993 and 1994, U.S. Environmental Protection Agency (U.S. EPA) conducted a Regional Environmental Monitoring and Assessment Program (REMAP) survey on wadeable streams in Colorado's (USA) Southern Rockies Ecoregion. In this ecoregion, mining over the past century has resulted in metals contamination of streams. The surveys collected data on fish and macroinvertebrate assemblages, physical habitat, and sediment and water chemistry and toxicity. These data provide a framework for assessing diagnostic community metrics for specific environmental stressors. We characterized streams as metals-affected based on exceedence of hardness-adjusted criteria for cadmium, copper, lead, and zinc in water; on water toxicity tests (48-h Pimephales promelas and Ceriodaphnia dubia survival); on exceedence of sediment threshold effect levels (TELs); or on sediment toxicity tests (7-d Hyalella azteca survival and growth). Macroinvertebrate and fish metrics were compared among affected and unaffected sites to identify metrics sensitive to metals. Several macroinvertebrate metrics, particularly richness metrics, were less in affected streams, while other metrics were not. This is a function of the sensitivity of the individual metrics to metals effects. Fish metrics were less sensitive to metals because of the low diversity of fish in these streams.

2002 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

International Nuclear Information System (INIS)

Stockton, M.

2003-01-01

For reporting year 2002, Los Alamos National Laboratory (LANL or the Laboratory) submitted Form R reports for lead compounds and mercury as required under the Emergency Planning and Community Right-to-Know Act (EPCRA), Section 313. No other EPCRA Section 313 chemicals were used in 2002 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical usage and threshold determinations for LANL for calendar year 2002 as well as provide background information about the data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxic Chemical Release Inventory report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999 EPA promulgated a final rule on Persistent Bioaccumulative Toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable under EPCRA Section 313. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R

2006 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

Energy Technology Data Exchange (ETDEWEB)

Ecology and Air Quality Group (ENV-EAQ)

2007-12-12

For reporting year 2006, Los Alamos National Laboratory (LANL or the Laboratory) submitted Form R reports for lead as required under the Emergency Planning and Community Right-to-Know Act (EPCRA) Section 313. No other EPCRA Section 313 chemicals were used in 2006 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2006, as well as to provide background information about data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxic Chemical Release Inventory Report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999, EPA promulgated a final rule on persistent bioaccumulative toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R.

Food plant toxicants and safety - Risk assessment and regulation of inherent toxicants in plant foods

DEFF Research Database (Denmark)

Essers, A.J.A.; Alink, G.M.; Speijers, G.J.A.

1998-01-01

The ADI as a tool for risk management and regulation of food additives and pesticide residues is not readily applicable to inherent food plant toxicants: The margin between actual intake and potentially toxic levels is often small; application of the default uncertainty factors used to derive ADI...... values, particularly when extrapolating from animal data, would prohibit the utilisation of the food, which may have an overall beneficial health effect. Levels of inherent toxicants are difficult to control; their complete removal is not always wanted, due to their function for the plant or for human...... health. The health impact of the inherent toxicant is often modified by factors in the food, e.g. the bioavailability from the matrix and interaction with other inherent constituents. Risk-benefit analysis should be made for different consumption scenarios, without the use of uncertainty factors. Crucial...

Anaerobic co-digestion of microalgal biomass and wheat straw with and without thermo-alkaline pretreatment.

Science.gov (United States)

Solé-Bundó, Maria; Eskicioglu, Cigdem; Garfí, Marianna; Carrère, Hélène; Ferrer, Ivet

2017-08-01

This study aimed at analyzing the anaerobic co-digestion of microalgal biomass grown in wastewater and wheat straw. To this end, Biochemical Methane Potential (BMP) tests were carried out testing different substrate proportions (20-80, 50-50 and 80-20%, on a volatile solid basis). In order to improve their biodegradability, the co-digestion of both substrates was also evaluated after applying a thermo-alkaline pretreatment (10% CaO at 75°C for 24h). The highest synergies in degradation rates were observed by adding at least 50% of wheat straw. Therefore, the co-digestion of 50% microalgae - 50% wheat straw was investigated in mesophilic lab-scale reactors. The results showed that the methane yield was increased by 77% with the co-digestion as compared to microalgae mono-digestion, while the pretreatment only increased the methane yield by 15% compared to the untreated mixture. Thus, the anaerobic co-digestion of microalgae and wheat straw was successful even without applying a thermo-alkaline pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Search for a Lipid Trigger: The Effect of Salt Stress on the Lipid Profile of the Model Microalgal Species Chlamydomonas reinhardtii for Biofuels Production.

Science.gov (United States)

Hounslow, Emily; Kapoore, Rahul Vijay; Vaidyanathan, Seetharaman; Gilmour, D James; Wright, Phillip C

2016-11-01

Algal cells produce neutral lipid when stressed and this can be used to generate biodiesel. Salt stressed cells of the model microalgal species Chlamydomonas reinhardtii were tested for their suitability to produce lipid for biodiesel. The starchless mutant of C. reinhardtii (CC-4325) was subjected to salt stress (0.1, 0.2 and 0.3 M NaCl) and transesterification and GC analysis were used to determine fatty acid methyl ester (FAME) content and profile. Fatty acid profile was found to vary under salt stress conditions, with a clear distinction between 0.1 M NaCl, which the algae could tolerate, and the higher levels of NaCl (0.2 and 0.3 M), which caused cell death. Lipid content was increased under salt conditions, either through long-term exposure to 0.1 M NaCl, or short-term exposure to 0.2 and 0.3 M NaCl. Palmitic acid (C16:0) and linolenic acid (C18:3n3) were found to increase significantly at the higher salinities. Salt increase can act as a lipid trigger for C. reinhardtii.

Community-Level Inequalities in Concussion Education of Youth Football Coaches.

Science.gov (United States)

Kroshus, Emily; Kerr, Zachary Y; Lee, Joseph G L

2017-04-01

USA Football has made the Heads Up Football (HUF) concussion education program available for coaches of youth football players. Existing evidence about the effectiveness of the HUF coach education program is equivocal. For HUF and other programs, there is growing concern that even effective interventions can increase inequalities if there is different uptake or impact by SES or other demographic factors. Understanding how adoption is patterned along these lines is important for understanding equity issues in youth football. This study tested the hypothesis that there will be lower adoption of HUF among coaches of youth football players in lower-SES communities. The authors conducted a cross-sectional study of the association between community-level characteristics and number of USA Football youth league coaches who have completed HUF. Data were collected in 2014 and analyzed in 2015-2016. Implementation of the HUF program was patterned by community-level socioeconomic characteristics. Leagues located in communities with a higher percentage of families with children aged football, it is important to consider not just the effectiveness of these interventions, but also whether they reduce or exacerbate health inequities. These results suggest that relying on voluntary adoption of coach education may result in inequitable implementation. Further study is required to identify and remedy organizational and contextual barriers to implementation of coach education in youth sport. Copyright © 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Lithium toxicity and myxedema crisis in an elderly patient.

Science.gov (United States)

Mir, Shahnaz Ahmad; Wani, Arshad Iqbal; Masoodi, Shariq Rashid; Bashir, Mir Iftikhar; Ahmad, Nadeem

2013-12-01

While thyroid dysfunction is a frequent complication of lithium treatment, myxedema crisis is a rare occurrence with a handful of cases described. Here, we describe a patient receiving lithium for about a decade for bipolar disorder, who presented with myxedema crisis and lithium toxicity. In this patient, myxedema crisis was likely precipitated by lithium toxicity and community acquired pneumonia. The effects of lithium on thyroid are briefly reviewed. To describe an elderly male who was diagnosed with myxedema crisis and lithium toxicity. A 70-year-old male was admitted in our hospital with history of gradual onset progressive decrease in level of consciousness and altered behavior for last 1 month. Patient also had history of respiratory tract symptoms for 1 week. Patient was a known case of diabetes and bipolar affective disorder for which he had been receiving insulin and lithium for 10 years. One year earlier, patient was admitted in our ward for glycemic control and evaluation of complications and was found to be clinically and biochemically euthyroid; he never returned for follow up until the present admission. On examination patient had incoherent speech, hypothermia, and bradycardia. Thyroid function showed thyroid-stimulating hormone >150 IU/ml, Tetraiodothyronine (T4) Coma Scale of 15/15, normal electrolyte, serum creatinine of 1.8 mg/dl and serum lithium level of 0.5 nmol/L. Lithium-induced hypothyroidism may be life-threatening, thyroid function should be monitored before and during lithium therapy and drug should be discontinued and appropriate therapy instituted if hypothyroidism develops.

[The umbilical blood levels of lead and some other toxic metals as a biomarker of environment-induced exposure].

Science.gov (United States)

Privalova, L I; Malykh, O L; Matiukhina, G V; Gnezdilova, S V

2007-01-01

Groups of pregnant women, which made up in Revda, Pervouralsk, Krasnouralsk, and Verkh-Isetsky District of Yekaterinburg, were studied. Tests of umbilical blood samples (UB) for the levels of calcium, iron, chromium, manganese, zinc, nickel, cadmium, lead, arsenic, copper, and mercury have established that the mean concentration of lead and the proportion of samples with elevated UB lead concentrations depend on how close the residential area is located to the major industrial source of emission of this toxic metal into ambient air. This correlation is less marked for other metals or it is not found. The particular position of lead is likely to be explained by the fact that it is entirely foreign to an organism and by the comparative unimportance of a contribution of the sources of exposure to this metal, which are unassociated with man-caused environmental and food pollution. As far as other metals are concerned, the situation is complicated by the fact that they are not only toxic, but when upon minor exposures, also essential biotrace elements with controlled and interdependent toxic kinetics. It is also shown that when a pregnant woman takes a complex of biological protectors promoting a reduction in her body's levels of lead, its concentrations in her body, its UB concentration is much lower than such a bioprophylactic effect is absent.

Cyanide toxicity to Burkholderia cenocepacia is modulated by polymicrobial communities and environmental factors

Directory of Open Access Journals (Sweden)

Steve P. Bernier

2016-05-01

Full Text Available Microbes within polymicrobial communities can establish positive and negative interactions that have the potential to influence the overall behaviour of the community. Pseudomonas aeruginosa and species of the Burkholderia cepacia complex (Bcc can co-exist in the lower airways, however several studies have shown that P. aeruginosa can effectively kill the Bcc in vitro, for which hydrogen cyanide was recently proposed to play a critical role. Here we show that modification of the environment (i.e. culture medium, long-term genetic adaptation of P. aeruginosa to the cystic fibrosis (CF lung, or the addition of another bacterial species to the community can alter the sensitivity of Burkholderia cenocepacia to P. aeruginosa toxins. We specifically demonstrate that undefined rich media leads to higher susceptibility of B. cenocepacia to P. aeruginosa toxins like cyanide as compared to a synthetic medium (SCFM, that mimics the CF lung nutritional content. Overall, our study shows that the polymicrobial environment can have profound effects on negative interactions mediated by P. aeruginosa against B. cenocepacia. In fact, evolved P. aeruginosa or the presence of other species such as Staphylococcus aureus can directly abolish the direct competition mediated by cyanide and consequently maintaining a higher level of species diversity within the community.

The transition from managed care to consumerism: a community-level status report.

Science.gov (United States)

Christianson, Jon B; Ginsburg, Paul B; Draper, Debra A

2008-01-01

This paper assesses the evolving "facilitated consumerism" model of health care at the community level using data from the Community Tracking Study (CTS). We find that in a relatively short time, large employers and health plans have made notable progress in putting the building blocks in place to support their vision of consumerism. However, developments in the CTS communities suggest that the consumerism strategy evolving in local markets is more nuanced than implied by some descriptions of health care consumerism.

Dynamic metabolic modeling of heterotrophic and mixotrophic microalgal growth on fermentative wastes.

Directory of Open Access Journals (Sweden)

Caroline Baroukh

2017-06-01

Full Text Available Microalgae are promising microorganisms for the production of numerous molecules of interest, such as pigments, proteins or triglycerides that can be turned into biofuels. Heterotrophic or mixotrophic growth on fermentative wastes represents an interesting approach to achieving higher biomass concentrations, while reducing cost and improving the environmental footprint. Fermentative wastes generally consist of a blend of diverse molecules and it is thus crucial to understand microalgal metabolism in such conditions, where switching between substrates might occur. Metabolic modeling has proven to be an efficient tool for understanding metabolism and guiding the optimization of biomass or target molecule production. Here, we focused on the metabolism of Chlorella sorokiniana growing heterotrophically and mixotrophically on acetate and butyrate. The metabolism was represented by 172 metabolic reactions. The DRUM modeling framework with a mildly relaxed quasi-steady-state assumption was used to account for the switching between substrates and the presence of light. Nine experiments were used to calibrate the model and nine experiments for the validation. The model efficiently predicted the experimental data, including the transient behavior during heterotrophic, autotrophic, mixotrophic and diauxic growth. It shows that an accurate model of metabolism can now be constructed, even in dynamic conditions, with the presence of several carbon substrates. It also opens new perspectives for the heterotrophic and mixotrophic use of microalgae, especially for biofuel production from wastes.

The effect of salinity levels on the structure of zooplankton communities

Directory of Open Access Journals (Sweden)

Paturej Ewa

2015-01-01

Full Text Available The objective of this study was to determine the qualitative and quantitative structure of zooplankton communities in the Vistula Lagoon and to establish whether zooplankton abundance and biodiversity are affected by salinity levels. Samples for biological analyses were collected in the summer (June-September of 2007-2011 at eleven sampling sites. Statistical analysis revealed a significant correlation between salinity levels and the number of species (r= -0.2020, abundance (r= 0.1967 and biomass (r= 0.3139 of zooplankton. No significant correlations were found between salinity and the biodiversity of zooplankton. The results of the study suggest that salinity affects the abundance and structure, but not the diversity of zooplankton communities in the Vistula Lagoon.

Theatre of the oppressed and environmental justice communities: a transformational therapy for the body politic.

Science.gov (United States)

Sullivan, John; Petronella, Sharon; Brooks, Edward; Murillo, Maria; Primeau, Loree; Ward, Jonathan

2008-03-01

Community Environmental Forum Theatre at UTMB-NIEHS Center in Environmental Toxicology uses Augusto Boal's Theatre of the Oppressed (TO) to promote involvement of citizens, scientists, and health professionals in deconstructing toxic exposures, risk factors, and cumulative stressors that impact the well-being of communities. The TO process encourages collective empowerment of communities by disseminating information and elaborating support networks. TO also elicits transformation and growth on a personal level via a dramaturgical system that restores spontaneity through image-making and improvisation. An NIEHS Environmental Justice Project, Communities Organized against Asthma & Lead, illustrates this interplay of personal and collective change in Houston, Texas.

Disentangling the effects of low pH and metal mixture toxicity on macroinvertebrate diversity

Science.gov (United States)

Fornaroli, Riccardo; Ippolito, Alessio; Tolkkinen, Mari J.; Mykrä, Heikki; Muotka, Timo; Balistrieri, Laurie S.; Schmidt, Travis S.

2018-01-01

One of the primary goals of biological assessment of streams is to identify which of a suite of chemical stressors is limiting their ecological potential. Elevated metal concentrations in streams are often associated with low pH, yet the effects of these two potentially limiting factors of freshwater biodiversity are rarely considered to interact beyond the effects of pH on metal speciation. Using a dataset from two continents, a biogeochemical model of the toxicity of metal mixtures (Al, Cd, Cu, Pb, Zn) and quantile regression, we addressed the relative importance of both pH and metals as limiting factors for macroinvertebrate communities. Current environmental quality standards for metals proved to be protective of stream macroinvertebrate communities and were used as a starting point to assess metal mixture toxicity. A model of metal mixture toxicity accounting for metal interactions was a better predictor of macroinvertebrate responses than a model considering individual metal toxicity. We showed that the direct limiting effect of pH on richness was of the same magnitude as that of chronic metal toxicity, independent of its influence on the availability and toxicity of metals. By accounting for the direct effect of pH on macroinvertebrate communities, we were able to determine that acidic streams supported less diverse communities than neutral streams even when metals were below no-effect thresholds. Through a multivariate quantile model, we untangled the limiting effect of both pH and metals and predicted the maximum diversity that could be expected at other sites as a function of these variables. This model can be used to identify which of the two stressors is more limiting to the ecological potential of running waters.

Community-level moderators of a school-based childhood sexual assault prevention program.

Science.gov (United States)

Morris, Matthew C; Kouros, Chrystyna D; Janecek, Kim; Freeman, Rachel; Mielock, Alyssa; Garber, Judy

2017-01-01

Childhood sexual abuse (CSA) is highly prevalent and associated with a wide variety of negative mental and physical health outcomes. School-based CSA education and prevention programs have shown promise, but it is unclear to what extent community-level characteristics are related to their effectiveness. The present cluster randomized controlled trial evaluated community-level moderators of the Safe@Lastprogramcomparedtoawaitlistcontrolcondition.(*) Knowledge gains from pre- to post-intervention were assessed in 5 domains: safe versus unsafe people; safe choices; problem-solving; clear disclosure; and assertiveness. Participants were 1177 students (46% White, 26% African American, 15% Hispanic, 4% Asian American, 6% Other) in grades 1 through 6 from 14 public schools in Tennessee. Multilevel models accounting for the nesting of children within schools revealed large effect sizes for the intervention versus control across all knowledge domains (d's ranged from 1.56 to 2.13). The effectiveness of the program was moderated by mean per capita income and rates of substantiated cases of child abuse and neglect in the community. Intervention effects were stronger for youth living in lower as compared to higher income counties, and for youth attending schools in counties with lower as compared to higher abuse/neglect rates. Child characteristics (sex, race) did not moderate intervention effects. This research identified two community-level factors that predicted the effectiveness of a CSA education and prevention program designed to improve children's knowledge of personal safety skills. School-based CSA prevention programs may require modification for communities with higher rates of child abuse and neglect. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioprinted 3D Primary Liver Tissues Allow Assessment of Organ-Level Response to Clinical Drug Induced Toxicity In Vitro.

Directory of Open Access Journals (Sweden)

Deborah G Nguyen

Full Text Available Modeling clinically relevant tissue responses using cell models poses a significant challenge for drug development, in particular for drug induced liver injury (DILI. This is mainly because existing liver models lack longevity and tissue-level complexity which limits their utility in predictive toxicology. In this study, we established and characterized novel bioprinted human liver tissue mimetics comprised of patient-derived hepatocytes and non-parenchymal cells in a defined architecture. Scaffold-free assembly of different cell types in an in vivo-relevant architecture allowed for histologic analysis that revealed distinct intercellular hepatocyte junctions, CD31+ endothelial networks, and desmin positive, smooth muscle actin negative quiescent stellates. Unlike what was seen in 2D hepatocyte cultures, the tissues maintained levels of ATP, Albumin as well as expression and drug-induced enzyme activity of Cytochrome P450s over 4 weeks in culture. To assess the ability of the 3D liver cultures to model tissue-level DILI, dose responses of Trovafloxacin, a drug whose hepatotoxic potential could not be assessed by standard pre-clinical models, were compared to the structurally related non-toxic drug Levofloxacin. Trovafloxacin induced significant, dose-dependent toxicity at clinically relevant doses (≤ 4uM. Interestingly, Trovafloxacin toxicity was observed without lipopolysaccharide stimulation and in the absence of resident macrophages in contrast to earlier reports. Together, these results demonstrate that 3D bioprinted liver tissues can both effectively model DILI and distinguish between highly related compounds with differential profile. Thus, the combination of patient-derived primary cells with bioprinting technology here for the first time demonstrates superior performance in terms of mimicking human drug response in a known target organ at the tissue level.

Community pharmacists' burnout levels and related factors: an example from Turkey.

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Calgan, Zeynep; Aslan, Dilek; Yegenoglu, Selen

2011-02-01

To determine community pharmacists' burnout levels and prevalences as well as factors associated with burnout. Study was conducted in Ankara, the capital of Turkey. In this cross-sectional study, 251 pharmacists were randomly selected from 1,504 community pharmacists registered in Ankara Chamber of Pharmacists. A questionnaire including questions related to pharmacists' individual and professional characteristics and Maslach Burnout Inventory was administered. The data was collected between February 27 and May 25, 2007. Three Maslach Burnout Inventory subscales (emotional exhaustion-EE, depersonalization-D, and personal accomplishment-PA) scores. Pharmacists' mean emotional exhaustion score was found to be 16.84 (SD: 6.25), depersonalization score was 4 (Range: 0-14), and personal accomplishment score was 22 (Range: 9-32). Of the pharmacists, 1.2% had high level of EE, .8% had high level of D, and 71.3% had high level of inefficacy. Age, marital status, work experience, work contentment, workload, time pressure, stress, and satisfaction with customers were found to be related with pharmacists' burnout levels. It can be useful to monitor pharmacists' burnout levels and prevalences periodically. Interventions on individual and organizational basis were needed to cope with burnout, respond to job demands, minimize the level of chronic stress, and increase work contentment and satisfaction.

Do Industries Pollute More in Poorer Neighborhoods? Evidence From Toxic Releasing Plants in Mexico

OpenAIRE

Lopamudra Chakraborti; José Jaime Sainz Santamaría

2015-01-01

Studies on industrial pollution and community pressure in developing countries are rare. We employ previously unused, self-reported toxics pollution data from Mexico to show that there exists some evidence of environmental justice concerns and community pressure in explaining industrial pollution behavior. We obtain historical data on toxic releases into water and land for the time period 2004 to 2012. We focus on 7 major pollutants including heavy metals and cyanide. To address endogeneity c...

Prenatal care utilization in Zimbabwe: Examining the role of community-level factors.

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Makate, Marshall; Makate, Clifton

2017-12-01

This paper assesses the importance of community-level factors on prenatal care utilization in Zimbabwe. The analysis is performed using data from the two most recent rounds of the nationally representative Demographic and Health Survey for Zimbabwe conducted in 2005/06 and 2010/11 linked with other community-level data. We use logistic, generalized linear regressions as well as multilevel mixed models to examine the factors associated with the frequency, timing and quality of prenatal care. Our results suggest that contraceptive prevalence, religious composition, density of nurses, health expenditures per capita and availability of government hospitals in communities are important predictors of prenatal care use in Zimbabwe. These findings have important implications for public health policy in Zimbabwe - a country with unfavorable maternal and child health outcomes. Copyright © 2017 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

Mutant LRRK2 Toxicity in Neurons Depends on LRRK2 Levels and Synuclein But Not Kinase Activity or Inclusion Bodies

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Skibinski, Gaia; Nakamura, Ken; Cookson, Mark R.

2014-01-01

By combining experimental neuron models and mathematical tools, we developed a “systems” approach to deconvolve cellular mechanisms of neurodegeneration underlying the most common known cause of Parkinson's disease (PD), mutations in leucine-rich repeat kinase 2 (LRRK2). Neurons ectopically expressing mutant LRRK2 formed inclusion bodies (IBs), retracted neurites, accumulated synuclein, and died prematurely, recapitulating key features of PD. Degeneration was predicted from the levels of diffuse mutant LRRK2 that each neuron contained, but IB formation was neither necessary nor sufficient for death. Genetic or pharmacological blockade of its kinase activity destabilized LRRK2 and lowered its levels enough to account for the moderate reduction in LRRK2 toxicity that ensued. By contrast, targeting synuclein, including neurons made from PD patient-derived induced pluripotent cells, dramatically reduced LRRK2-dependent neurodegeneration and LRRK2 levels. These findings suggest that LRRK2 levels are more important than kinase activity per se in predicting toxicity and implicate synuclein as a major mediator of LRRK2-induced neurodegeneration. PMID:24403142

Ecological effects of ionizing radiation and other toxic agents on the aquatic microcosm

International Nuclear Information System (INIS)

Fuma, Shoichi; Ishii, Nobuyoshi; Tanaka, Nobuyuki; Takeda, Hiroshi; Miyamoto, Kiriko; Yanagisawa, Kei; Kawabata, Zen'ichiro

2004-01-01

The purpose of this study was comparative evaluation of effects of ionizing radiation and other various toxic agents on aquatic microbial communities. For this purpose, the authors investigated effects of γ-rays, ultraviolet (UV) radiation, acidification, aluminum, manganese, nickel, copper and gadolinium on the microcosm, i.e., the experimental model ecosystem consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Eseherichia coli as a decomposer. Effects of toxic agents in the microcosm were not only direct effects but also community-level effects due to interactions among the constituting species or between organisms and toxic agents. In general, the degrees of effects observed in the microcosm could be categorized as follows: no effects; recognizable effects, i.e., decrease or increase in the cell densities of at least one species; severe effects, i.e., extinction of one or two species; and destructive effects, i.e., extinction of all species. These results were analyzed by the ecological effect index (EEI), in which differences in the cell densities between exposed and control microcosm were represented by the Euclidean distance function. A 50% effect doses for the microcosm (ED M50 ), at which the EEI became 50%, were evaluated to be 530 Gy for γ-rays, 2100 J m -2 for UV, 4100 μM for manganese, 45 μM for nickel, 110 μM for copper and 250 μM for gadolinium. (author)

Increased Growth of the Microalga Chlorella vulgaris when Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium Azospirillum brasilense†

Science.gov (United States)

Gonzalez, Luz E.; Bashan, Yoav

2000-01-01

Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacterium Azospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments. PMID:10742237

Disparities in Children’s Blood Lead and Mercury Levels According to Community and Individual Socioeconomic Positions

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Lim, Sinye; Ha, Mina; Hwang, Seung-Sik; Son, Mia; Kwon, Ho-Jang

2015-01-01

We aimed to examine the associations between blood lead and mercury levels and individual and community level socioeconomic positions (SEPs) in school-aged children. A longitudinal cohort study was performed in 33 elementary schools in 10 cities in Korea. Among a total of 6094 children included at baseline, the final study population, 2281 children followed-up biennially, were analyzed. The geometric mean (GM) levels of blood lead were 1.73 μg/dL (range 0.02–9.26) and 1.56 μg/dL (range 0.02–6.83) for male and female children, respectively. The blood lead levels were significantly higher in males, children living in rural areas, and those with lower individual SEP. The GM levels of blood mercury were 2.07 μg/L (range 0.09–12.67) and 2.06 μg/L (range 0.03–11.74) for males and females, respectively. Increased blood mercury levels were significantly associated with urban areas, higher individual SEP, and more deprived communities. The risk of high blood lead level was significantly higher for the lower individual SEP (odds ratio (OR) 2.18, 95% confidence interval (CI) 1.36–3.50 in the lowest educational attainment of the father), with a significant dose-response relationship observed after adjusting for the community SEP. The association between high blood lead levels and lower individual SEP was much stronger in the more deprived communities (OR 2.88, 95% CI 1.27–6.53) than in the less deprived communities (OR 1.40, 95% CI 0.76–2.59), and showed a significant decreasing trend during the follow-up only in the less deprived communities. The risk of high blood mercury levels was higher in higher individual SEP (OR 0.64, 95% CI 0.40–1.03 in the lowest educational attainment of the father), with a significant dose-response relationship noted. Significant decreasing trends were observed during the follow-up both in the less and more deprived communities. From a public health point-of-view, community level intervention with different approaches for

Comparing rankings of selected TRI organic chemicals for two environments using a level III fugacity model and toxicity

International Nuclear Information System (INIS)

Edwards, F.G.; Egemen, E.; Nirmalakhandan, N.

1998-01-01

The Toxics Release Inventory, TRI (USEPA, 1995) is a comprehensive listing of chemicals, mass released, source of releases, and other related information for chemicals which are released into the environment in the US. These chemicals are then ranked according to the mass released as a indication of their environmental impact. Industries have been encouraged to adopt production methods to decrease the release of chemicals which are ranked highly in the TRI. Clearly, this ranking of the chemicals based upon the mass released fails to take into account very important environmental aspects. The first and most obvious aspect is the wide range of toxicity's of the chemicals released. Numerous researchers have proposed systems to rank chemicals according to their toxicity. The second aspect, which a mass released based ranking does not take into account, is the fate and transport of each chemical within the environment. Cohen and Ryan (1985) and Mackay and Paterson (1991) have proposed models to evaluate the fate and transport of chemicals released into the environment. Some authors have incorporated the mass released and toxicity with some fate and transport aspects to rank the impact of released chemicals. But, due to the complexities of modeling the environment, the lack of published data on properties of chemicals, and the lack of information on the speciation of chemicals in complex systems, modeling the fate and transport of toxic chemicals in the environment remains difficult. To provide an indication of the need to rank chemicals according to their environmental impact instead of the mass released, the authors have utilized a subset of 45 organic chemicals from the TRI, modeled the fate and transport of the chemicals using a Level III fugacity model, and compared those equilibrium concentrations with toxicity data to yield a hazard value for each chemical

Sensitivity of screening-level toxicity tests using soils from a former petroleum refinery

International Nuclear Information System (INIS)

Pauwels, S.; Bureau, J.; Roy, Y.; Allen, B.; Robidoux, P.Y.; Soucy, M.

1995-01-01

The authors tested five composite soil samples from a former refinery. The samples included a reference soil (Mineral Oil and Grease, MO and G < 40 ppm), thermally-treated soil, biotreated soil, and two untreated soils. They evaluated toxicity using the earthworm E. foetida, lettuce, cress, barley, Microtox, green algae, fathead minnow, and D. magna. The endpoints measured were lethality, seed germination, root elongation, growth, and bioluminescence. Toxicity, as measured by the number of positive responses, increased as follows: biotreated soil < untreated soil No. 1 < reference soil < thermally-treated soil and untreated soil No. 2. The biotreated soil generated only one positive response, whereas the thermally-treated soil and untreated soil No. 2 generated five positive responses. The most sensitive and discriminant terrestrial endpoint was lettuce root elongation which responded to untreated soil No. 1, thermally-treated soil, and reference soil. The least sensitive was barley seed germination for which no toxicity was detected. The most sensitive and discriminant aquatic endpoint was green algae growth which responded to untreated soil No. 1, thermally-treated soil, and reference soil. The least sensitive was D. magna for which no toxicity was detected. Overall, soil and aqueous extract toxicity was spotty and no consistent patterns emerged to differentiate the five soils. Biotreatment significantly reduced the effects of the contamination. Aqueous toxicity was measured in the reference soil, probably because of the presence of unknown dissolved compounds in the aqueous extract. Finally, clear differences in sensitivity existed among the test species

Community-level income inequality and HIV prevalence among persons who inject drugs in Thai Nguyen, Vietnam.

Science.gov (United States)

Lim, Travis W; Frangakis, Constantine; Latkin, Carl; Ha, Tran Viet; Minh, Nguyen Le; Zelaya, Carla; Quan, Vu Minh; Go, Vivian F

2014-01-01

Socioeconomic status has a robust positive relationship with several health outcomes at the individual and population levels, but in the case of HIV prevalence, income inequality may be a better predictor than absolute level of income. Most studies showing a relationship between income inequality and HIV have used entire countries as the unit of analysis. In this study, we examine the association between income inequality at the community level and HIV prevalence in a sample of persons who inject drugs (PWID) in a concentrated epidemic setting. We recruited PWID and non-PWID community participants in Thai Nguyen, Vietnam, and administered a cross-sectional questionnaire; PWID were tested for HIV. We used ecologic regression to model HIV burden in our PWID study population on GINI indices of inequality calculated from total reported incomes of non-PWID community members in each commune. We also modeled HIV burden on interaction terms between GINI index and median commune income, and finally used a multi-level model to control for community level inequality and individual level income. HIV burden among PWID was significantly correlated with the commune GINI coefficient (r = 0.53, p = 0.002). HIV burden was also associated with GINI coefficient (β = 0.082, p = 0.008) and with median commune income (β = -0.018, p = 0.023) in ecological regression. In the multi-level model, higher GINI coefficient at the community level was associated with higher odds of individual HIV infection in PWID (OR = 1.46 per 0.01, p = 0.003) while higher personal income was associated with reduced odds of infection (OR = 0.98 per $10, p = 0.022). This study demonstrates a context where income inequality is associated with HIV prevalence at the community level in a concentrated epidemic. It further suggests that community level socioeconomic factors, both contextual and compositional, could be indirect determinants of HIV infection in PWID.

Community-Level Income Inequality and HIV Prevalence among Persons Who Inject Drugs in Thai Nguyen, Vietnam

Science.gov (United States)

Lim, Travis W.; Frangakis, Constantine; Latkin, Carl; Ha, Tran Viet; Minh, Nguyen Le; Zelaya, Carla; Quan, Vu Minh; Go, Vivian F.

2014-01-01

Socioeconomic status has a robust positive relationship with several health outcomes at the individual and population levels, but in the case of HIV prevalence, income inequality may be a better predictor than absolute level of income. Most studies showing a relationship between income inequality and HIV have used entire countries as the unit of analysis. In this study, we examine the association between income inequality at the community level and HIV prevalence in a sample of persons who inject drugs (PWID) in a concentrated epidemic setting. We recruited PWID and non-PWID community participants in Thai Nguyen, Vietnam, and administered a cross-sectional questionnaire; PWID were tested for HIV. We used ecologic regression to model HIV burden in our PWID study population on GINI indices of inequality calculated from total reported incomes of non-PWID community members in each commune. We also modeled HIV burden on interaction terms between GINI index and median commune income, and finally used a multi-level model to control for community level inequality and individual level income. HIV burden among PWID was significantly correlated with the commune GINI coefficient (r = 0.53, p = 0.002). HIV burden was also associated with GINI coefficient (β = 0.082, p = 0.008) and with median commune income (β = −0.018, p = 0.023) in ecological regression. In the multi-level model, higher GINI coefficient at the community level was associated with higher odds of individual HIV infection in PWID (OR = 1.46 per 0.01, p = 0.003) while higher personal income was associated with reduced odds of infection (OR = 0.98 per $10, p = 0.022). This study demonstrates a context where income inequality is associated with HIV prevalence at the community level in a concentrated epidemic. It further suggests that community level socioeconomic factors, both contextual and compositional, could be indirect determinants of HIV infection in PWID. PMID

Toxicity formation and distribution in activated sludge during treatment of N,N-dimethylformamide (DMF) wastewater

Energy Technology Data Exchange (ETDEWEB)

Yang, Na; Chen, Xiurong, E-mail: xrchen@ecust.edu.cn; Lin, Fengkai; Ding, Yi; Zhao, Jianguo; Chen, Shanjia

2014-01-15

Highlights: • We studied mechanism of sludge organic toxicity formation in wastewater treatment. • The organic toxicity distributed mainly in the inner section of sludge flocs. • The organic toxicity of sludge increased with DMF initial concentrations increments. • The property of bacteria community correlates significantly with sludge toxicity. -- Abstract: The organic toxicity of sludge in land applications is a critical issue; however, minimal attention has been given to the mechanism of toxicity formation during high-strength wastewater treatment. To investigate the relevant factors that contribute to sludge toxicity, synthetic wastewater with N,N-dimethylformamide (DMF) was treated in a sequential aerobic activated sludge reactor. The acute toxicity of sludge, which is characterised by the inhibition rate of luminous bacteria T3, is the focus of this study. Using an operational time of 28 days and a hydraulic retention time of 12 h, the study demonstrated a positive relationship between the acute toxicity of sludge and the influent DMF concentration; the toxicity centralised in the intracellular and inner sections of extracellular polymeric substances (EPS) in sludge flocs. Due to increased concentrations of DMF, which ranged from 40 to 200 mg L{sup −1}, the sludge toxicity increased from 25 to 45%. The organic toxicity in sludge flocs was primarily contributed by the biodegradation of DMF rather than adsorption of DMF. Additional investigation revealed a significant correlation between the properties of the bacterial community and sludge toxicity.

Rapid adaptation of microalgae to bodies of water with extreme pollution from uranium mining: an explanation of how mesophilic organisms can rapidly colonise extremely toxic environments.

Science.gov (United States)

García-Balboa, C; Baselga-Cervera, B; García-Sanchez, A; Igual, J M; Lopez-Rodas, V; Costas, E

2013-11-15

Extreme environments may support communities of microalgae living at the limits of their tolerance. It is usually assumed that these extreme environments are inhabited by extremophile species. However, global anthropogenic environmental changes are generating new extreme environments, such as mining-effluent pools of residual waters from uranium mining with high U levels, acidity and radioactivity in Salamanca (Spain). Certain microalgal species have rapidly adapted to these extreme waters (uranium mining in this area began in 1960). Experiments have demonstrated that physiological acclimatisation would be unable to achieve adaptation. In contrast, rapid genetic adaptation was observed in waters ostensibly lethal to microalgae by means of rare spontaneous mutations that occurred prior to the exposure to effluent waters from uranium mining. However, adaptation to the most extreme conditions was only possible after recombination through sexual mating because adaptation requires more than one mutation. Microalgae living in extreme environments could be the descendants of pre-selective mutants that confer significant adaptive value to extreme contamination. These "lucky mutants" could allow for the evolutionary rescue of populations faced with rapid environmental change. Copyright © 2013 Elsevier B.V. All rights reserved.

A comparative study of soft sensor design for lipid estimation of microalgal photobioreactor system with experimental validation.

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Yoo, Sung Jin; Jung, Dong Hwi; Kim, Jung Hun; Lee, Jong Min

2015-03-01

This study examines the applicability of various nonlinear estimators for online estimation of the lipid concentration in microalgae cultivation system. Lipid is a useful bio-product that has many applications including biofuels and bioactives. However, the improvement of lipid productivity using real-time monitoring and control with experimental validation is limited because measurement of lipid in microalgae is a difficult and time-consuming task. In this study, estimation of lipid concentration from other measurable sources such as biomass or glucose sensor was studied. Extended Kalman filter (EKF), unscented Kalman filter (UKF), and particle filter (PF) were compared in various cases for their applicability to photobioreactor systems. Furthermore, simulation studies to identify appropriate types of sensors for estimating lipid were also performed. Based on the case studies, the most effective case was validated with experimental data and found that UKF and PF with time-varying system noise covariance is effective for microalgal photobioreactor system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Temporal changes in the diazotrophic bacterial communities associated with Caribbean sponges Ircinia stroblina and Mycale laxissima.

Science.gov (United States)

Zhang, Fan; Vicente, Jan; Hill, Russell T

2014-01-01

Sponges that harbor microalgal or, cyanobacterial symbionts may benefit from photosynthetically derived carbohydrates, which are rich in carbon but devoid of nitrogen, and may therefore encounter nitrogen limitation. Diazotrophic communities associated with two Caribbean sponges, Ircinia strobilina and Mycale laxissima were studied in a time series during which three individuals of each sponge were collected in four time points (5:00 AM, 12:00 noon, 5:00 PM, 10:00 PM). nifH genes were successfully amplified from the corresponding gDNA and cDNA pools and sequenced by high throughput 454 amplicon sequencing. In both sponges, over half the nifH transcripts were classified as from cyanobacteria and the remainder from heterotrophic bacteria. We found various groups of bacteria actively expressing the nifH gene during the entire day-night cycle, an indication that the nitrogen fixation potential was fully exploited by different nitrogen fixing bacteria groups associated with their hosts. This study showed for the first time the dynamic changes in the activity of the diazotrophic bacterial communities in marine sponges. Our study expands understanding of the diazotrophic groups that contribute to the fixed nitrogen pool in the benthic community. Sponge bacterial community-associated diazotrophy may have an important impact on the nitrogen biogeochemical cycle in the coral reef ecosystem.

Temporal changes in the diazotrophic bacterial communities associated with Caribbean sponges Ircinia stroblina and Mycale laxissima

Directory of Open Access Journals (Sweden)