Movement and metabolism of S‐benzyl O,O‐diisopropyl phosphorothiolate (Kitazin P^®) and O‐ethyl S,S‐diphenyl phosphorodithiolate (edifenphos) in various types of soils

Abstract

Movement and Metabolism of ³²P and ³⁵S‐double labeled Kitazin P^® (S‐benzyl O,O‐diisopropyl phosphorothiolate) and ³⁵S‐labeled edifenphos (O‐ethyl S,S‐diphenyl phosphorodithiolate) were examined with three types of soils, sandy loam, alluvial clay loam, and volcanic ash loam. Vertical movement of both the compounds in soil column was different with soil types, and the order of mobility in soil column was as follows: sandy loam >alluvial clay loam>volcanic ash loam. Persistence of edifenphos in soil was shorter than that of Kitazin P. Main degradation products at the initial stage of metabolism were S,S,S‐triphenyl phosphorotrithiolate, O,O‐diethyl S‐phenyl phosphorothiolate, S‐phenyl dihydrogen phosphorothiola and diphenyl disulfide in edifenphos and O,O‐diisopropyl hydrogen phosphorothioate in Kitazin P. Sulfur atom of Kitazin P was found in sulfurio acid at a minor level through dibenzyl disulfide and toluene‐α‐sulfonic acid, and that of edifenphos was converted to sulfuric acid through diphenyl disulfide and benzenesulfonic acid. Kitazin P under flooded condition of alluvial clay loam was slightly more persistent as compared with upland condition. Sterilized condition of Kitazin P did not cause any appreciable degradation throughout the experimental period, but such condition did not necessarily prevent the degradation of edifenphos.

Key words:

• Movement and metabolism
• Organophosphorus fungicides
• Soils