CCA News & Information Articles

The microbial arsenic cycle in Mono Lake, California 04-03-2004 Significant concentrations of dissolved inorganic arsenic can be found in the waters of a number of lakes located in the western USA and in other water bodies around the world. These lakes are often situated in arid, volcanic terrain. The highest concentrations of arsenic occur in hypersaline, closed basin soda lakes and their remnant brines. Although arsenic is a well-known toxicant to eukaryotes and prokaryotes alike, some prokaryotes have evolved biochemical mechanisms to exploit arsenic oxyanions (i.e., arsenate and arsenite); they can use them either as an electron acceptor for anaerobic respiration (arsenate), or as an electron donor (arsenite) to support chemoautotrophic fixation of CO2 into cell carbon. Unlike in freshwater or marine ecosystems, these processes may assume quantitative significance with respect to the carbon cycle in arsenic-rich soda lakes. For the past several years our research has focused on the occurrence and biogeochemical manifestations of these processes in Mono Lake, a particularly arsenic-rich environment. Herein we review some of our findings concerning the biogeochemical arsenic cycle in this lake, with the hope that it may broaden the understanding of the influence of microorganisms upon the speciation of arsenic in more common, less "extreme" environments, such as drinking water aquifers. Reliability of a commercial kit to test groundwater for arsenic in Bangladesh 01-01-2005 Abstract: A comparison of field and laboratory measurements of arsenic in groundwater of Araihazar, Bangladesh, indicates that the most widely used field kit correctly determined the status of 88% of 799 wells relative to the local standard of 50 microg/L As. Direct data manipulation for local decision analysis as applied to the problem of arsenic in drinking water from tube wells in Bangladesh 12-01-2004 Abstract: A wide variety of tools are available, both parametric and nonparametric, for analyzing spatial data. However, it is not always clear how to translate statistical inferences into decision recommendations. A new metabolic pathway of arsenite: arsenic-glutathione complexes are substrates for human arsenic methyltransferase 11-04-2004 Abstract: The metabolism of arsenic is generally accepted to proceed by repetitive reduction and oxidative methylation; the latter is mediated by arsenic methyltransferase (Cyt19). Testing groundwater for arsenic in Bangladesh before installing a well 12-15-2004 Abstract: Profiles of groundwater and sediment properties were collected at three sites in Bangladesh with an inexpensive sampling device that is deployed by modifying the local manual drilling method. Development of a sampling train for arsenic in pyrolysis vapours resulting from pyrolysis of arsenic containing wood waste. 10-19-2004 In the present study a sampling and analysis method for arsenic emissions during pyrolysis of arsenic containing wood, such as chromated copper arsenate (CCA) treated wood, has been developed. Nitrogen purity influences the occurrence of As+ ions in high-performance liquid chromatography/electrospray ionization mass spectrometric analysis of four common arsenosugars. pub med