Arsenic degradation

Arsenate degradation 3 cycles, 40-fold improvement in Crameri et al,... 

Lewisite in soil may rapidly volatilize or may be converted to lewisite oxide due to moisture in the soil (Rosenblatt et al, 1975). The low water solubility suggests intermediate persistence in moist soil (Watson and Griffin, 1992). Both lewisite and lewisite oxide may be slowly oxidized to 2-chlorovinylarsonic acid (Rosenblatt et al, 1975). Possible pathways of microbial degradation in soil include epoxidation of the C=C bond and reductive deha-logenation and dehydrohalogenation (Morrill et al, 1985). Due to the epoxy bond and arsine group, toxic metabolites may result. Additionally, residual hydrolysis may result in arsenic compounds. Lewisite is not likely to bioaccumulate. However, the arsenic degradation products may bioaccumulate (Rosenblatt et al, 1975). 

Sulfur mustard can be considered environmentally persistent because it is chemically stable and of low volatility. When protected from weathering conditions, it may persist in soil for years. VX is moderately persistent because of low volatility and slow rate of hydrolysis. The G-agents can be considered non-persistent on the basis of volatility and hydrolysis rates. Depending on environmental conditions, their half-lives may be measured in hours to days. Lewisite is rapidly hydrolyzed but the insoluble oxide formed is stable in the environment. In addition, arsenical degradation products of lewisite persist in the environment. Because of its extreme volatility and relatively rapid hydrolysis, cyanogen chloride is not persistent in the environment. 

A major concern when remediating wood-treatment sites is that pentachlorophenol was often used in combination with metal salts, and these compounds, such as chromated copper—arsenate, are potent inhibitors of at least some pentachlorophenol degrading organisms (49). Sites with significant levels of such inorganics may not be suitable candidates for bioremediation. 

The selective epoxidation of ethylene by hydrogen peroxide ia a 1,4-dioxane solvent ia the presence of an arsenic catalyst is claimed. No solvent degradation is observed. Ethylene oxide is the only significant product detected. The catalyst used may be either elemental arsenic, an arsenic compound, or both. 

The molar ratio of these compounds was approximately 3 2. They could not be transformed into each other, and separation of the isomers has not yet been successful. Evidently, the initial product mixture, containing phosphorus-rich polycyclic compounds, was degraded into the bicyclic 48 and 49. Similar product mixtures, for which structures have been established, were also observed by the analogous transformation of ( > 1,2-di-re rf-butyl- 1,2-dimesityldisilene and tetramesityldisilene with white phosphorus and yellow arsenic (As4), respectively.46... 

Botrytis cinerea is responsible for gray mold disease in more than 200 host plants. This necrotrophic fungus displays the capacity to kill host cells through the production of toxins and reactive oxygen species and the induction of a plant-produced oxidative burst. Thanks to an arsenal of degrading enzymes, B. cinerea is then able to feed on various plant tissues (Choquer and others 2007). 

Arsenic in upper finer sediment has been releasing due to the microbial degradation driven by the dissolution of the Fe-AI minerals ... 

Timms P, MacRae IC (1982) Conversion of fensulfothion by klebsiella-pneumoniae to fensul-fothion sulfide and its accumulation. Australian J Biological Sciences 35 661-667 Tournassat C, Charlet L, Bosbach D, Manceau A (2002) Arsenic (III) oxidation by bimessite and precipitation of manganese (II) arsenate. Environ Sci Technol 36 493-500 Wahid PA, Ramakrishna C, Sethunathan N (1980) Instantaneous degradation of parathion in anaerobic soUs. J Environ Qual 9 127-130... 

Those siderophores with low molecular weight, nonpeptidal structures are anticipated to be stable to proteolytic enzymatic degradation, and less likely to evoke an immune response. The antibiotic can be selected from commercial sources or from a large arsenal of potential antibiotics with low solubility that were overlooked, or never underwent extensive clinical investigations. 

Arsene, M., Favetta, P., Favier, B., and Bureau, J. (2002), Comparison of ceftazidime degradation in glass bottles and plastic bags, I. Clin. Pharm. Ther., 27(3), 202-209. 

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