Isolation of organophosphorus pesticides degrading bacteria found in soil and bovine milk

Abstract

The increasing use of organophosphorus pesticides in agricultural practices over the past few years has generated a number of environmental problems; these compounds tend to bio-accumulate through food chains showing high levels of toxicity triggering potential health risk for species that are exposed to these substances. In this research were used the Soxhlet and solid phase micro extraction in headspace (HS- SPME) methods for the extraction of organophosphorus pesticides in agricultural cattle soils and bovine milk, respectively. The presence of demeton-S-methylsulfon was determined at concentrations between 272.9 and 1793.3 ppm in cropland and 12.9 ppm in cow milk. Native soil bacteria were isolated showing degrading capacity of these pesticides, Bacillus sp and Pantoea agglomerans which gave results of degradation of 73.5% and 68.6%, respectively, in the concentration of chlorpyrifos, showing that these microorganisms are a possible solution for improving soils contaminated by this class of pesticides.