Detection of Bis(diphenylarsine)oxide, Diphenylarsinic Acid and Phenylarsonic Acid, Compounds Probably Derived from Chemical Warfare Agents, in Drinking Well Water

The inhabitants living in a specific region of Kizaki area in Kamisu-town, Ibaraki Prefecture exhibited uncommon clinical central nervous system symptoms. A graphite furnace atomic absorption spectrophotometer detected markedly elevated concentration of arsenic (4.5 ppm) in their drinking well water. Further investigation using HPLC, GC/MS and HPLC/ICP/MS demonstrated that the structures of the arsenic were bis(diphenylarsine)oxide (BDPAO), diphenylarsinic acid (DPAA) and phenylarsonic acid (PAA), compounds that can be derived from the chemical warfare agents, diphenylchloroarsine (DA) and diphenylcyanoarsine (DC). The predominant form of the arsenic compound in the well water was DPAA (maximum 15 ppm), so that it was calculated that the inhabitants ingested 11-30 mg of DPAA daily. This is the first report of inhabitants that were injured by drinking well water contaminated with organic arsenic compounds that were likely derived from chemical weapons.