Photochemical decomposition of arsenic species in natural waters

Publisher Website
Google Scholar
Abstract
The rates of photochemical decomposition of arsenic(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenobetaine have been studied in both aerated and deaerated distilled water and seawater. In distilled water, the ultimate product is arsenic(V) with the rates of demethylation of DMA and MMA being relatively unaffected by dissolved oxygen, unlike the rate of arsenic(III) oxidation. In seawater, the demethylation reaction is extremely slow whereas the oxidation of arsenic(III) is only slightly slower than in distilled water. The implications, both for arsenic speciation in natural waters and for the use of u.v. decomposition in arsenic analysis, are discussed.