Alterations in Haematological and Biochemical Profile of Freshwater Fish, Cirrhinus mrigala (Hamilton) Exposed to Sub-Lethal Concentrations of Chlorpyrifos

Pesticide pollution in aquatic ecosystems is an environmental issue throughout the world. Chlorpyrifos is the most widely used organophosphate pesticide against pests in agricultural farms, orchards of fruit trees and household purposes. Herein, we investigated the impact of sublethal toxicity of this organophosphate on some haematological and biochemical parameters of freshwater fish Cirrhinus mrigala. The acute median lethal concentration (LC₅₀) value of chlorpyrifos calculated by probit analysis was found to be 0.44 mg L^-1. On the basis of LC₅₀ value, the fingerlings were exposed to three sublethal concentrations (1/20^th, 1/10^th, 1/5^th) of chlorpyrifos. During the prolonged treatment, haematological parameters including RBC, Hb and Hct values were found to decrease, whereas WBC count was found to increase in pesticide treated fishes. Similarly, indices like MCH and MCHC were significantly lower and MCV was significantly higher when compared to control. In the biochemical study, values of plasma glucose showed a gradual increase, whereas plasma protein levels, albumin and globulin showed a gradual decrease with increase in dose of chlorpyrifos at the end of experimental period. Results of the study clearly revealed that chlorpyrifos can disrupt the haematological and biochemical parameters of Cirrhinus mrigala and these can be used as non specific biomarkers in pesticide contaminated aquatic ecosystems.