http://precedings.nature.com/tags/arsenic Recently posted documents tagged with 'arsenic' Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://dx.doi.org/10.1038/npre.2009.3663.1 The objective of our studies is to analyze environmental impacts of Monosodium Methane Arsenate, MSMA, on aquatic habitats using the Aqua-Terra microcosm system. MSMA was applied at environmentally relevant(recommended) doses to microcosms to determine the change in biodiversity and the bio-concentration of arsenic in the aquatic plants (Elodea Sp.) used in the microcosms as an oxygen source. The microcosms are filled with unfiltered pond water and the diversity of each microcosm was determined before application of the herbicide. After population stabilization, the herbicide is applied to the terrestrial portion of the microcosm. The herbicide is watered into the microcosm by allowing the herbicide to be filtered by soil into the aquatic portion of the microcosm. Diversity of the microcosm was determined by physical counts of invertebrate organisms and quantified using Simpson’s Index of Diversity. Calculating Simpson’s Index of Diversity indicate there is an overall decline in the diversity of the microcosms from 0.327 to 0.763 for recommended manufacturer’s formulation and 0.512 to 0.546 for twice the recommended manufacturer’s formulation. Plants take up arsenic using the same metabolic pathways that they use to take up phosphorus. This makes arsenic available for trophic transfer to the primary consumers as any primary producer is consumed. In Elodea sp., total arsenic concentrations (ashed from fresh samples) range from 15 ppb to 214 ppb before and after application of the herbicide. Water samples show the same increase, from 5 ppb to 70 ppb before and after application. These data indicate that the arsenic in the MSMA compound is either being liberated by bacterial decomposing or it is passing through the soil unmodified. http://dx.doi.org/10.1038/npre.2009.3663.1 Fri, 21 Aug 2009 19:44:42 UTC Changes in Simpson’s Diversity Index in Microcosms Impacted with Monosodium Methane Arsenate doi:10.1038/npre.2009.3663.1 2009-08-21 Peter A. Kish Nature Precedings 2009-08-21T19:44:42Z Poster Ecology http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2992/version/1 The present study was carried out on the basis of status of arsenic in soil, drinking water and plants, blood, urine and faeces of animals at arsenic prone zone. Within the ambit with the environment, the examination of animals was taken into consideration. They were screened and categorised on the degree of As toxicity. For field works animals were randomly selected from arsenic prone zone. The external manifestation indicated a complex syndrome and characteristic signs such as increased heart rate and respiratory rate, red urine, congested mucous membrane, anorexia, absence of ruminal motility, diarrhoea with blood, polyuria and unusual weight loss. The haematobiochemical changes such as low Hb level, decreased level of TEC, TLC and increased level ALT, AST, BUN and creatinine. Increased level of arsenic in urine, blood and faeces than the value of control animals could be the confirmatory indication of arsenic toxicity. http://precedings.nature.com/documents/2992/version/1 Tue, 31 Mar 2009 18:40:33 UTC Study on the effect of toxicity under highly arsenic prone zone in Nadia district of West Bengal in India hdl:10101/npre.2009.2992.1 2009-03-31 Tanmoy Rana Nature Precedings 2009-03-31T18:40:33Z Manuscript Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/1482/version/1 All known life requires phosphorus (P) in the form of inorganic phosphate (PO4- or Pi) and phosphate-containing organic molecules. Pi serves as the backbone of the nucleic acids that constitute genetic material and as the major repository of chemical energy for metabolism in polyphosphate bonds. Arsenic (As) lies directly below P on the periodic table and so the two elements share many chemical properties, although their chemistries are sufficiently dissimilar that As cannot directly replace P in modern biochemistry. Arsenic is toxic precisely because As and P are similar enough that organisms attempt this substitution. We hypothesize that ancient biochemical systems, analogous to but distinct from those known today, could have utilized arsenate in the equivalent biological role of phosphate. Organisms utilizing such “weird life” biochemical pathways may have supported a “shadow biosphere” at the time of the origin and early evolution of life on Earth or on other planets. Such organisms may even persist on Earth today, undetected, in unusual niches. http://precedings.nature.com/documents/1482/version/1 Wed, 02 Jan 2008 22:43:38 UTC Did nature also choose arsenic? hdl:10101/npre.2008.1482.1 2008-01-02 Felisa Wolfe-Simon Nature Precedings 2008-01-02T22:43:38Z Manuscript Chemistry Evolutionary Biology http://creativecommons.org/licenses/by/3.0/