Lindane degradation and effects on soil microbial activity

The degradation of U-C-14-lindane in two Egyptian soils was determined in a three-month laboratory incubation. Lindane mineralization was slow and limited in both soils. Evolution of (CO2)-C-14 increased with time bur only reached 3.5 to 5.5% of the initial C-14-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 C-14 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 (CO2)-C-14 evolution from U-(14) C-glucose and microbial activity was significantly inhibited by 10 mg lindane/kg soil.