Stability of bacterial populations in tropical soil upon exposure to Lindane

The effect of the pesticide Lindane on microbial populations was analyzed in soil with a history of contamination with various chemicals, including this pesticide. Soil microcosms were amended with 100 mg Lindane/kg soil and microbial populations were monitored for 70 days. Bacterial cell concentrations, metabolic versatility (whole community Biolog), and genetic diversity (16S rDNA/denaturing gradient gel electrophoresis) were used to monitor microbial communities. Results show the persistence of Lindane in the soil environment; at the end of the experiment, 70% of the added Lindane remained undegraded. A reduction of 50% in bacterial cell concentration was observed in Lindane-amended microcosms during the 2nd week of the experiment. This reduction was correlated with a reduction in the rate of substrate utilization as observed by Biolog. Overall, no effect of Lindane was observed on the metabolic versatility and genetic diversity in these soils, demonstrating the ability of these bacterial populations to tolerate the pressure caused by the addition of pesticides.