The Metabolism Of Arsenite

Up to 200 million people in 70 countries are at risk from drinking water contaminated with arsenic, which is a major cause of chronic debilitating illnesses and fatal cancers. Until recently little was known about the mobility of arsenic, and how redox transformations determined its movement into or out of water supplies. Although human activities contribute to the release of arsenic from minerals, it is now clear that bacteria are responsible for most of the redox transformation of arsenic in the environment. Bacterial oxidation of arsenite (to the less mobile arsenate) has been known since 1918, but it was not until 2000 that a bacterium was shown to gain energy from this process. Since then a wide range of arsenite-oxidizing bacteria have been isolated, including aerobes and anaerobes; heterotrophs and autotrophs; thermophiles, mesophiles and psychrophiles. This book reviews recent advances in the study of such bacteria. After a section on background—geology and health issues—the main body of the book concerns the cellular machinery of arsenite oxidation. It concludes by examining possible applications. Topics treated are: The geology and cycling of arsenic Arsenic and disease Arsenite oxidation: physiology, enzymes, genes, and gene regulation. Community genomics and functioning, and the evolution of arsenite oxidation Microbial arsenite oxidation in bioremediation Biosensors for arsenic in drinking water and industrial effluents

Handbook of Arsenic Toxicology, Second Edition presents the latest findings on arsenic, including its chemistry, sources and effects on the environment and human health. The book discusses both acute and chronic effects, discussing many aspects of arsenic, from physical and chemical properties, exposure, epidemiology, organ toxicity, diagnosis, prevention and treatment. Fully updated and revised, this new edition includes new topics on risk assessment, molecular mechanisms of arsenic, advances in the integrated approach to testing, assessment and development, evaluation and application of high content predictive models, and new alternative methods (NAMS) in the context of Adverse Outcome Pathways (AOPs) to assess toxicology. This comprehensive resource allows readers to effectively assess the risks related to arsenic, providing them with all they need to know on arsenic exposure, toxicity and toxicity prevention. Brings together current findings on the effects of arsenic on the environment and human health Includes state-of-the-art techniques in arsenic toxicokinetics, speciation and molecular mechanisms Provides all the information needed for effective risk assessment, prevention and countermeasures

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.

The U.S. Environmental Protection Agency (EPA) has been considering a more stringent regulation of arsenic in water. A significant reduction in the maximum contaminant level (MCL) could increase compliance costs for water utilities. This book discusses the adequacy of the current EPA MCL for protecting human health in the context of stated EPA policy and provides an unbiased scientific basis for deriving the arsenic standard for drinking water and surface water. Arsenic in Drinking Water evaluates epidemiological data on the carcinogenic and noncarcinogenic health effects of arsenic exposure of Taiwanese populations and compares those effects with the effects of arsenic exposure demonstrated in other countries—including the United States. The book also reviews data on toxicokinetics, metabolism, and mechanism and mode of action of arsenic to ascertain how these data could assist in assessing human health risks from arsenic exposures. This volume recommends specific changes to improve the toxicity analyses and risk characterization. The implications of the changes for EPA’s current MCL for arsenic are also described.

This book provides valuable new insights into preventive measures for chronic arsenic poisoning, exploring the various causes, metabolism and toxicity, preventive drugs, functional foods and various methods for removing arsenic from contaminated water. The mechanisms of chronic arsenic poisoning vary between countries and regions, and the pathological difference, though reported on, is still only poorly understood. As large-scale chronic arsenic poisoning is concentrated in Asia, the contributions in this book were written by pioneers from Asia. Further, the management of removed arsenic has not yet become standardized, and this volume will serve as a vital source of new ideas by highlighting significant detoxification methods aimed at the disposal of arsenic. Arsenic Contamination in Asia represents a valuable sourcebook for scientists working in the fields of environmental health, occupational health, environmental science, fisheries science, agriculture, pharmacy, analytical chemistry, and clinical medicine. Also, beginning researchers, seasoned experts, and students who are seeking comprehensive information on the natural sciences including medicine will find this work thought-provoking, instructive and informative.

In biochemistry, a metalloprotein is a generic term for a protein that contains a metal cofactor. The metal may be an isolated ion or may be coordinated with a nonprotein organic compound, such as the porphyrin found in hemoproteins. In some cases, the metal is co-coordinated with a side chain of the protein and an inorganic nonmetallic ion. This kind of protein-metal-nonmetal structure is seen in iron-sulfur clusters Metalloproteins deals with all aspects related to the intracellular and extracellular metal-binding proteins, including their structures, properties and functions. The biological roles of metal cations and metal-binding proteins are endless. They are involved in all crucial cellular activities. Many pathological conditions are related to the problematic metal metabolism. Research in metalloprotein-related topics is therefore rapidly growing, and different aspects of metal-binding proteins progressively enter curricula at Universities and even at the High School level on occasion. However, no key resource providing basic, but comprehensible knowledge on this rapidly expanding field exists. The Encyclopedia of Metalloproteins aims to bridge this gap, and will attempt to cover various aspects of metalloprotein/metalloproteomics and will deal with the different issues related to the intracellular and extracellular metal-binding proteins, including their structures, properties and functions. The goal is to cover exhaustively all catalytically and biologically crucial metal ions and to find at least one interacting protein for other metal ions. The Encyclopedia of Metalloproteins will provide a key resource for advanced undergraduate and graduate students, researchers, instructors, and professors interested in protein science, biochemistry, cell biology, and genetics.