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Arsenic Speciation in Algae, Volume 85, addresses the most important issues to consider during arsenic speciation in algae, including new sections on Occurrence, distribution, and significance of arsenic speciation, Biogeochemistry of arsenic in aquatic environments: the role of speciation, Sampling and sampling processing: fit for purpose techniques, Separation methods applied to arsenic speciation, Detection and quantification of arsenic compounds, Analytical approaches for proteomics and lipidomics of arsenic in algae, Quality control and quality assurance issues in arsenic speciation, Arsenic speciation in algae: case studies in Europe, and more. Features the latest content combined with the experience of our distinguished contributors
The arsenic concentration and speciation of marine algae varies widely, from 0.4 to 23 ng.mg−1, with significant differences in both total arsenic content and arsenic speciation occurring between algal classes. The Phaeophyceae contain more arsenic than other algal classes, and a greater proportion of the arsenic is organic. The concentration of inorganic arsenic is fairly constant in macro-algae, and may indicate a maximum level, with the excess being reduced and methylated. Phytoplankton take up As(V) readily, and incorporate a small percentage of it into the cell. The majority of the As(V) is reduced, methylated, and released to the surrounding media. The arsenic speciation in phytoplankton and Valonia also changes when As(V) is added to cultures. Arsenate and phosphate compete for uptake by algal cells. Arsenate inhibits primary production at concentrations as low as 5 .mu.g.1−1 when the phosphate concentration is low. The inhibition is competitive. A phosphate enrichment of> 0.3 .mu.M alleviates this inhibition; however, the As(V) stress causes an increase in the cell's phosphorus requirement. Arsenite is also toxic to phytoplankton at similar concentrations. Methylated arsenic species did not affect cell productivity, even at concentrations of 25 .mu.g.1−1. Thus, the methylation of As(V) by the cell produces a stable, non-reactive compound which is nontoxic. The uptake and subsequent reduction and methylation of As(V) is a significant factor in determining the arsenic biogeochemistry of productive systems, and also the effect that the arsenic may have on algal productivity. Therefore, the role of marine algae in determining the arsenic speciation of marine systems cannot be ignored. (ERB).
Arsenic Speciation in Algae, Volume 85, addresses the most important issues to consider during arsenic speciation in algae, including new sections on Occurrence, distribution, and significance of arsenic speciation, Biogeochemistry of arsenic in aquatic environments: the role of speciation, Sampling and sampling processing: fit for purpose techniques, Separation methods applied to arsenic speciation, Detection and quantification of arsenic compounds, Analytical approaches for proteomics and lipidomics of arsenic in algae, Quality control and quality assurance issues in arsenic speciation, Arsenic speciation in algae: case studies in Europe, and more. Features the latest content combined with the experience of our distinguished contributors
Having safe drinking water is important to all Americans. The Environmental Protection Agency's decision in the summer of 2001 to delay implementing a new, more stringent standard for the maximum allowable level for arsenic in drinking water generated a great deal of criticism and controversy. Ultimately at issue were newer data on arsenic beyond those that had been examined in a 1999 National Research Council report. EPA asked the National Research Council for an evaluation of the new data available. The committee's analyses and conclusions are presented in Arsenic in Drinking Water: 2001 Update. New epidemiological studies are critically evaluated, as are new experimental data that provide information on how and at what level arsenic in drinking water can lead to cancer. The report's findings are consistent with those of the 1999 report that found high risks of cancer at the previous federal standard of 50 parts per billion. In fact, the new report concludes that men and women who consume water containing 3 parts per billion of arsenic daily have about a 1 in 1,000 increased risk of developing bladder or lung cancer during their lifetime.
Arsenic is a toxic element and its effects on humans, animals and other organisms are well documented. A method to accurately determine the concentration as well as the speciation of arsenic in highly complex evaporation pond water and algae will be discussed. Interestingly, microorganisms are thriving in evaporation ponds that have high levels of arsenic, which is unusual for their survival. This study shows nine different arsenic species including the most common: AsB, As(III), MMA, DMA, As(V), and four different arsenosugars. This research determined that there were 99 ± 120 μg of As per mL in the water samples, which mostly consisted of As(III) and As(V). The algae samples had a total concentration of 522 ± 179 μg of As per mL, and consisted of As(III), As(V), AsB, arsenosugar 1 (291 ± 289 μg of As per mL) and arsenosugar 2 (9.62 ± 39.6 μg of As per mL). The ultimate goal of this ongoing project was to determine if algae from these evaporation ponds may effect oxidation of the most toxic As(III) to the less toxic As(V). If so, these detoxifying algae may have important ecotoxicity and environmental health implications.
Arsenic is one of the most toxic and carcinogenic elements in the environment. This book brings together the current knowledge on arsenic contamination worldwide, reviewing the field, highlighting common themes and pointing to key areas needing future research. Contributions discuss methods for accurate identification and quantification of individual arsenic species in a range of environmental and biological matrices and give an overview of the environmental chemistry of arsenic. Next, chapters deal with the dynamics of arsenic in groundwater and aspects of arsenic in soils and plants, including plant uptake studies, effects on crop quality and yield, and the corresponding food chain and human health issues associated with these exposure pathways. These concerns are coupled with the challenge to develop efficient, cost effective risk management and remediation strategies: recent technological advances are described and assessed, including the use of adsorbants, photo-oxidation, bioremediation and electrokinetic remediation. The book concludes with eleven detailed regional perspectives of the extent and severity of arsenic contamination from around the world. It will be invaluable for arsenic researchers as well as environmental scientists and environmental chemists, toxicologists, medical scientists, and statutory authorities seeking an in-depth view of the issues surrounding this toxin.