Lindane degradation and effects on soil microbial activity

The degradation of U-14C-lindane in two Egyptian soils was determined in a three-month laboratory incubation. Lindane mineralization was slow and limited in both soils. Evolution of 14CO2 increased with time but only reached 3.5 to 5.5% of the initial 14C-concentration within 90 days. At that time both soils contained about 88% of the applied radiocarbon; 33% to 37% of the initial dose was unextractable and assumed bound to the soils. The methanol-extractable 14C primarily contained lindane with traces of minor metabolites. Radiorespirometry was used to evaluate the effect of lindane on soil microbial activity. Low concentrations of the insecticide initially supressed 14CO2 evolution from U-14C-glucose and microbial activity was significantly inhibited by 10 mg lindane/kg soil.