Dissipation of Bifenthrin in Water as Affected by pH and Temperature

A laboratory experiment was conducted to study the persistence of bifenthrin in water at different pH ann temperature conditions. To study the effect of pH, fortified water samples at pH 4.0 (acidic), 7.0 (neutral) and 9.2 (alkaline) were incubated at 25°C. Effect of temperature was studied at 5, 25 and 40°C with water samples fortified at 1.0 μg/ml lelel. Residues were estimated by GLC-ECD at different time intervals. Results revealed that the residues in all the treatments persisted beyond 45 days. Dissipation at different pH revealed that bifenthrin was most stable under alkaline pH followed by neutral and acidic pH. Half-llfe values at different pH varied ffom 14.8–42.4 days. Bifenthrin residues dissipated fastest at 40°C (T_½ 27.4 days) followed by 25 (T_½ 32.4 days) and 5°C(T_½ 44.3 days). Dissipation in all cases followed first order kinetics.