Abstract

Chlorpyrifos a broad-spectrum insecticide is effective in controlling cutworms, corn root worms, cockroaches, flies, termites, fire ants, beetles and lice. Though the use of Chlorpyrifos is banned in many developed countries, it is still widely used in developing countries like India. The widespread use of Chlorpyrifos is found to accumulate in soil and also gets leached into water bodies, making the environment polluted and is found to be toxic to non target organisms. The present study reports the bioremediation studies of Chlorpyrifos in agricultural soils of Visakhapatnam district. Bacterial strains were isolated from agricultural soils from different land use patterns of Visakhapatnam dist. The isolates were identified as Bacillus aryabhattai, Bacillus drentensis, Bacillus firmus, and Staphylococcus vitulinus. The degradation potential of the organisms were studied using Chlorpyrifos as the only carbon source and also the influence of Cow dung manure and NPK fertilizer on the growth and degradation capacity of organisms were studied. Degradation potential in media for individual organism as well as consortia was studied using spectrophotometric analysis. The degradation of microbial consortia in soil was detected using LC-MS to know the intermediate metabolites formed during degradation. It was found that the bacterial consortium has the highest degradation potential compared to individual organisms and also Bacillus drentensis is found to degrade Chlorpyrifos effectively compared to other organisms.

Keywords: Bioremediation; Chlorpyrifos; Cow dung manure; NPK fertilizer; Spectrophotometric analysis; LC-MS