Acute toxicity of diazinon and its effects on hematological parameters in the Indian carp, Cirrhinus mrigala (Hamilton)

Diazinon is a commonly used pesticide and its existence in the fresh water reservoirs of Pakistan has been reported by some authors. A semistatic experiment was conducted to find out the acute toxicity of diazinon as an aquatic pollutant on some hematological parameters of Indian carp (Cirrhinus mrigala). The 1, 24, 48, 72, and 96 h LC50 values of diazinon for Indian carp were estimated as 17.32 mg/L, 15.39 mg/L, 12.64 mg/L, 10.98 mg/L, and 8.15 mg/L respectively. A significant increase in the number of dead fish was observed as the concentration of diazinon and exposure time increased (P < 0.05). The results after acute exposure to 8.15 mg/L of diazinon for 96 h showed that compared to the control fish, the total erythrocytes, leukocytes, hemoglobin, and hematocrit values decreased significantly (P < 0.05) in exposed fish. The mean corpuscular volume and mean corpuscular hemoglobin increased significantly (P < 0.05), while the mean corpuscular hemoglobin concentration of both groups remained unchanged during the study. In conclusion, acute exposure to LC50 values of diazinon induced hematological alterations in Indian carp and offers a tool to evaluate toxicity derived alterations.