Sorption of Pesticides by Volcanic Ash Soil from Mt. Aso in "Simulated Weathering" Experiments

Abstract

We previously reported 1,2) that volcanic ash soil from Mt. Aso may affect the quality of water in the regions where volcanic ash from the present crater in Naka-dake have been deposited, and that adsorption of pesticides (Environmental standards and items requiring observation according to the Fundamentals of Environment Act) by volcanic ash soil from Mt. Aso may be affected by the water-solubility of chemicals and the kinds and number of hydrophilic functional groups at the molecular level of chemicals. The present study using "simulated weathering" (treatment with humic acid) demonstrated that the pesticides that the absorption efficiency improved by treated humic acid treated were 2,2-dichlorovinyldimethylphosphate (DDVP), 2-sec-butylphenyl methylcarbamate (BPMC), O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate (MEP), Bebthiocarb, Isoxathion, 4-nitrophenyl 2,4,6-trichlorophenyl ether (CNP), and deteriorated adversely in Propyzamide, Diazinon.