Degradation of chlorothalonil in soils treated repeatedly with chlorothalonil

摘要

It has been observed that degradation of a fungicide chlorothalonil is suppressed in soils with repeated application of chlorothalonil. Motonaga et al. reported the suppression of chlorothalonil degradation by an inhibitory metabolite, 2,5,6-trichloro-4-hydroxyisophthalonitrile (abbreviated as HO), that was produced in the soil and in a pure culture. Previously, metabolic pathways of chlorothalonil in soil have been studied with or without ratio-labeled chlorothalonil. Chlorothalonil degradation was started by substitution of chlorine with a hydroxyl group, dechlorination and hydrolysis of the nitrile group. However, most of these metabolic studies have been carried out using virgin soils. It is essential to examine the metabolic pathways in soils treated with chlorothalonil repeatedly.