Stability of [14C]Lindane, [14C]Chlorpyrifos, and Coumaphos in Model Cattle Dip

Stabilities of lindane, chlorpyrifos, and coumaphos were studied in simulated cattle dipping vat. The half-life ( DT 50 ) of lindane was found to be only 4 days. By 9 weeks' time, 99% of the lindane had dissipated from model vat. Chlorpyrifos was insoluble in water. The first-phase half-life of chlorpyrifos was found to be 22 days. Bound chlorpyrifos in soil was found at less than 5%. Stability of coumaphos was found to be related with the pH of water. The first-phase half-life ( DT 50 ) of coumaphos in the control vat was 99 days, which increased to 114 days in the vat containing superphosphate fertilizer used as buffer but remained 98 days with sodium citrate. Chlorferon, potasan, and an unidentified compound were found to be present with coumaphos. Keywords: Acaricides; lindane; chlorpyrifos; coumaphos; cattle dip