Studies on the effect of chlorpyrifos (organophosphate) and cypermethrin (synthetic pyrethroid) on the growth of Paramecium

Abstract

Interest in the toxicity of pesticides has increased as they enter waterways from agricultural and urban runoffs and may end up in aquatic environment and bioaccumulate in the food chain. The aim of this study was to determine the effect of two insecticides; Chlorpyrifos and Cypermethrin on aquatic protozoa (Paramecium). The test was carried out in laboratory, where Monoxenic culture of Paramecium was used to test the effect of Chlorpyrifos and Cypermethrin at 50, 25, 12.5, 6.25, 3.125, 1 respectively, at time interval of 24, 48, and 72 hours. The effect of Chlorpyrifos on Paramecium growth showed significant different with P value 0.0228, while for Cypermethrin, there was no significant difference with P value of 0.1333. The damage was more at 24hrs interval, as the number of population growth increased with time. Hence, the effect of the insecticides reduced. Conclusively, both insecticides showed harmful effect to Paramecium and may disturb the aquatic ecosystem.

Keywords: Chlorpyrifos, Cypermethrin, Paramecium, Monoxenic culture, Toxicity