Decomposition of Oxamyl in Soil and Water

Abstract

Oxamyl was stable in water at pH 5 or lower, but hydrolyzed rapidly to the oximino compound (I) at pH 9. Ultraviolet light accelerated hydrolysis and caused the formation of the syn-anti isomer of I. In river water exposed to sunlight, oxamyl hydrolyzed immediately to I, which gradually was converted to its isomer and to N,N-dimethyloxamic acid (III) and CO2. In soil [14C]oxamyl degraded rapidly to 14CO2. Traces of I and a polar fraction were extractable, and radioactivity became incorporated into normal soil organic matter. Under anaerobic conditions, oxidation to CO2 and incorporation into organic matter were delayed. These results were confirmed in field studies where the half-life of oxamyl was about 1 week. © 1978, American Chemical Society. All rights reserved.