Conversion and Species Distribution Characteristics of Arsenical Chemical Agent in the Soil Contaminated by Chemical Weapons Abandoned by Japan

In order to phytoremediation the soils contaminated by arsenical chemical weapons abandoned by Japan at some region of Jilin Province and ready for the estimate of the ecological safety, this paper analyzed organic species in soil with GC-MS, disscussed extraction and testing of inorganic arsenic in soil with hydrochloric acid, studied species of arsenic in soil such as available forms, valence state, and combined state, and inferred conversion process of arsenical chemical agent. The results indicate that after simple destroying and long time burial, almost all arsenical chemical agents in soil at this region are converted into inorganic arsenic due to explosion, burning, natural oxidation and microorganism, which primarily exists as As (V). Organic arsenic was only detected at where shells were buried (destroyed), in leaded shells and contaminated soil, with its content 3.65%~32.03%; Organic arsenic content of soil in other part is less than 10%. In contaminated soil of this region, water soluble arsenic and available arsenic extracted from disodium hydrogen phosphate take 0.81~2.58% and 7.49~15.96% of total arsenic respectively. Exchangeable As and binding As (Al-As, Fe-As, reducible As and Ca-As) take 40% of total arsenic, residual As takes 49.38~66.43%. The results may be used as basis for determining remedy methods and assessing ecological safety at this region.