Acute Toxicity of Cypermethrin to Freshwater Fish Oreochromis niloticus: Influence of Aquatic Weed and Turbidity of Water

Abstract

Cypermethrin is a common pollutant of freshwater ecosystem in India. In this study, static bioassays were conducted to evaluate how toxicity of Cypermethrin to freshwater fish Oreochromis niloticus changed with hydro-biological conditions of water. 72-h LC50 of Cypermethrin to O. niloticus was found as 5.05 µg/L. The LC50 value significantly increased in the presence of the aquatic weed Azolla pinnata (150 g/10L). Toxicity of Cypermethrin to fish also reduced with the increase in turbidity of water. It was concluded that determination of lethality of Cypermethrin to fish should be based on ambient conditions of the medium.