Abstract
The degradation of pyrazolate was studied in soils under laboratory conditions by using 14C-preparations labeled separately at the pyrazole and chlorinated benzene rings. Pyrazolate was hydrolyzed at the ester bond to give p-toluenesulfonic acid (PTSA) and the herbicidal entity, 4-(2, 4-dichlorobenzoyl)-1, 3-dimethyl-5-hydroxypyrazole (DTP). The half-lives in two soils under flooded conditions were about 10 days. PTSA labeled with 14C at the benzene ring was rapidly mineralized to CO2, while DTP was relatively persistent in soils. DTP underwent oxidation at the 1- and 3-methyl groups, cleavage of the benzoyl bond, fission of the pyrazole and benzene rings, and was ultimately mineralized to CO2.
