Degradation of MCPBE, Simetryne and Methoxyphenone in Reductive Flooded Soils

Abstract

Degradation of MCPBE (ethyl 2-methyl-4-chlorophenoxybutylate), simetryne [2-methylthio-4, 6-bis(ethylamino)-s-triazine] and methoxyphenone (3, 3′-dimethyl-4-methoxybenzophenone) in the reductive flooded soils was compared with those in the usually prepared flooded soils. MCPBE was degraded in the reductive soils as rapidly as in the usually prepared ones having a half-life time of less than one day, and free acid (MCPBA, 2-methyl-4-chlorophenoxybutylic acid) was formed correspondingly. The acid was also degraded rapidly in both soil conditions. MCPA (2-methyl-4-chlorophenoxyacetic acid) was formed in the usually prepared soils but not detected in the reductive soils. Half-life time of simetryne in the two soils was 37 and 63 days under reductive conditions and 48 and 58 days under usually prepared conditions. Methoxyphenone was rapidly degraded at almost the same rate under both soil conditions and the main metabolite was methoxyphenone-OH (3, 3′-dimethyl-4-hydroxybenzophenone). The behavior of the three herbicides in the soils was almost the same under both conditions and no long persistence was observed.