Degradation of pesticides in soil as influenced by the presence of hydrolysis metabolites

Abstract

Abstract The degradation of 8 pesticides was evaluated in a soil pretreated with their respective hydrolysis metabolites. 2,4‐Dichlorophenol, p‐nitrophenol, and salicylic acid conditioned the soil for enhanced degradation of 2,4‐dichlorophenoxyacetic acid (2,4‐D), parathion, and isofenphos, respectively. Repeated application of carbofuran phenol, 2‐isopropyl‐4‐methyl‐6‐hydroxypyrimidine, methyl phenyl sulfone, thiophenol, isopropyl salicylate, and 2,4,5‐trichlorophenol had no effect on the rate of degradation of their parent pesticides. Prior exposure of soil to 3,5,6‐trichloro‐2‐pyridinol resulted in increased persistence of its parent compound, chlorpyrifos. Results indicate that pesticide hydrolysis metabolites can effect the induction or inhibition of enhanced microbial degradation of some soil‐applied pesticides.