Triflusulfuron-methyl dissipation in water and soil

This paper reports laboratory studies of the behavior and fate of triflusul furon-methyl in aqueous buffer and soils. Aqueous hydrolysis was pH-depende nt and fast in acidic buffer solutions. In basic buffers, the hydrolysis ra te variation was low between pH 7 and pH 10. The degradation pathway in the range of pH 4-10 was via cleavage of the sulfonylurea bridge to form two t ransformation products: 2-amino-4-(dimethylamino)-6-(2,2,2-trifluoroethoxy) -1,3,5-triazine (2) and 6-methyl-2-methylcarboxylate benzene sulfonamide (3 ). Comparison of transformation rates in sterile and nonsterile soils indic ates that chemical and microbial processes are important in soil degradatio n. The former is more important in acidic soils, and the latter is more imp ortant in basic soils. A biphasic model fits well with dissipation of trifl usulfuron-methyl in soil. The triazine formed during the first step of tran sformation was degraded more rapidly in basic soils than in acidic soils.