Environmental concerns arsenic compounds

Concerning anthropogenic sources, methyl arsenic compounds such as methyl arsonic acid and dimethylarsinic acid have been used as herbicides, and were once a significant source of environmental residues. Dimethyl-arsinic acid (Agent Blue) was used as a defoliant during the Vietnam War. 

Diphenylchloroarsine (DA, Clark I) hydrolysis in water will lead to diphenylarsenious acid and hydrochloric acid and diphenylcyanoarsine (DC, Clark II) will lead to hydrogen cyanide and diphenylarsenious oxide. Both acids are toxic, nevertheless they will be detoxified quickly in water. Both arseno-organic compounds from the hydrolysis can later be decomposed into inorganic arsenic compounds, and they will remain toxic. As for all arsenic compounds, the possible bio-accumulation would be a problem of environmental concern. 

Speciation of compounds of environmental concern is another important application of coupled GC-ICP-MS and LC-ICP-MS. Arsenic compounds in shellfish are one example of the importance... 

Chromated copper arsenate, made from a mixture of copper, chromium, and arsenic compounds, has been used to protect wood for outdoor applications from decay and insects since the 1930s. Treated wood has a characteristic light green color. Environmental concerns led to restrictions on the use of this pre servative for residential timber in the U.S. and Europe banning in 2004. IVeated wood is still legal for many applications, and a great deal of treated wood remains in structures built before tbe ban. 

Toxicity. While many new materials are added to the adhesive chemist s arsenal, some are being removed as well. Compounds which cause health and environmental concern include ethylenimine, methylene-fcw(o-chloroan-iline) (MOCA), hexamethylene diisocyanate, formaldehyde. Some systems are no longer in use in others, modifications have been made. Thus radiation-curing technology is replacing some types of multifunctional acrylate monomers with alkoxylated compounds, because the latter are less irritating and less toxic. An example is trimethylolpropane triethoxy triacrylate. 

For many years, arsenic has been regarded as an important environmental pollutant. It can enter the environment in many ways, for example use as an agrochemical, in smelting operations, and from coal fired power plants. Buchet and Lauwerys [70] list the relative toxicities for several arsenic compounds of high concern. In descending order they give arsine > arsenite > arsenate > methanearsonic acid (MMA) > dimethylarsinic acid (cacodylic acid, DMA). Methods which can accurately assess environmental and occupational exposure to these toxic arsenic compounds are necessary. 

The next eight chapters will be devoted to the ecotoxicology of groups of compounds that have caused concern on account of their real or perceived environmental effects and have been studied both in the laboratory and in the field. These are predominantly compounds produced by humans. However, a few of them, for example, methyl mercury, methyl arsenic, and polycyclic aromatic hydrocarbons (PAHs), are also naturally occurring. In this latter case, there can be difficulty in distinguishing between human and natural sources of harmful chemicals. 

Apart from their pharmaceutical applications, the organic arsenicals are also used as herbicides. The main compounds are monosodium methanarsonate (MSMA) and hydroxydimethylarsine oxide (cacodylic acid). The relatively wide use of these agents is one of the main reasons for concern about their potential hazard to public health. Additionally, bioaccumulation of organic arsenicals in aquatic organisms such as seaweeds, freshwater algae and Crustacea plays a major role in the evaluation of the toxicity of these materials. Consequently, human exposure to organic arsenicals due to the combination of environmental and therapeutic applications is the main cause of the variety of toxic manifestations of these compounds. 

This review describes factors concerning the safety and environmental effects of organic arsenic, antimony and bismuth compounds. The factors involve the production and use of the elements, toxicity, pollution, metabolism (alkylation), health effect assessment, fate and so on. 

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