Abstract

The acute effect of diazinon on the African catfish (Clarias gariepinus) was assessed by comparing the biochemical blood plasma profiles of a control group and a group exposed to the effect of the pesticide Diazintol^R (162 mg/ml of diazinon as the active substance). The activities of selected enzymes, metabolite and electrolytes concentrations were measured on 16 specimens of controls, and in 20 specimens, of (C. gariepinus of mean weight 350 ± 15 g, and mean total length 35 ± 2.0 cm) exposed for 96 h to the effects of Diazintol^R at a concentration of 6.6 ppm. The results showed a significant decrease of cholinesterase (p < 0.05) lactate dehydrogenase (p < 0.05) alkaline phosphatase and acid phosphatase in the experimental group. The values of alanine and aspartate, aminotransferases, creatine kinase, were comparable in the experimental and control groups. A significant decrease (p < 0.05) was observed in the total protein, albumin globulin and lactate concentration in the experimental group compared with the control group. Glucose concentration in the plasma of the experimental group was significantly higher (p < 0.05) than that of the control group. A significantly higher (p < 0.05) concentration of plasma sodium and potassium was observed in the experimental group and a significantly lower (p < 0.05) concentration of plasma calcium and phosphorus, compared with those in the control group. The results of the biochemical blood plasma profile indicate a marked neurotoxic effect of diazinon and shows that this changes could be used as biomarkers for aquatic pollution.

Key words: Organophosphorous pesticide, acute toxicity, enzymes, total protein, glucose, lactate, electrolytes.