Biodegradation of C-14-chlorpyrifos by hairy root culture of Chenopodium amaranticolor Coste & Reynier

摘要

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro- 2-pyridyl phosphorothioate) is a broad-spectrum insecticide used against a wide range of insect and arthropod pests. It is an anticholinesterase agent effective by contact, ingestion and vapour action. Owing to the ban on the usage of many organochlorine insecticides, organophosphorous insecticides like chlorpyrifos have attained importance. Because of its versatility, chlorpyrifos is used globally in a myriad of pest-control situations. Chlorpyrifos is registered for use in over 900 different formulations. In 1997, Dursban (a commercial formulation) was found in more than 25% of surface waters sampled for pesticide by the US Geological Survey. Elevated groundwater contamination has been found in areas where it is used as termiticide. Depending on the pesticide formulation and the form used for application (liquid, aerosol, solid or powder), chlorpyrifos residues may be detectable in water, soil and plant surface for months or even years. In contrast to several other organophosphorus pesticides like parathion, fenitrothion, dichlorovos and diazinon, persistence of chlorpyrifos is unaffected in a medium (peptone and glucose media containing 20 ppm chlorpyrifos) containing various cultures of bacteria like Pseudomonas spp., Bacillus spp. and others1. The degradation of 14Cchlorpyrifos in model rice ecosystem was studied in our laboratory, where degradation of chlorpyrifos to 3,5,6-trichloro-2- pyridinol (TCP) was demonstrated2, while rapid chlorpyrifos degradation in a medium was shown by a mixture of different fungi compared to the medium with single fungus.