Degradation of Mecoprop in Soil

Abstract

Gas chromatography and a root growth inhibition bioassay were used in an investigation of the degradation of mecoprop (a phenoxy acid herbicide) in field soil under glasshouse conditions. These 2 methods yielded similar dissipation curves. The correlation coefficient was 0.958. Mecoprop was degraded fairly rapidly both in soil treated with 5 mg and in soil treated with 15 mg mecoprop per kg soil. The study was made under conditions that favored microbial degradation. One possible degradation pathway for mecoprop is an initial decarboxylation followed by stepwise oxidation to yield MCPA, a related phenoxy acid herbicide. Soil that was treated with mecoprop was periodically analyzed for the presence of MCPA. This hypothetical metabolite was, however, not detected in any sample of the soil treated with mecoprop.