الفهرس 
Classification of pesticidesOnly 14 pages are availabe for public view
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Abstract
Diazinon is widely and effectively used in agriculture as well in domestic and aquaculture applications. As a result of its widespread, ecotoxicity is awaited and therefore a study is needed to determine its effects on the aquatic organisms and its potential effects as an environmental contaminant. In this study, the half lethal concentration (LC50) of diazinon for Clarias gariepinus (C. gariepinus) was calculated. Diazinon toxicity was evaluated through acute and chronic exposures of fish to 1/2 and 1/10 the calculated LC50 for 1week & 6 weeks respectively. Results showed that the LC50 /96h was 5.98 ppm. The effects of both acute and chronic exposures revealed clinical abnormalities in the form of nervous and respiratory disorders manifested by erratic swimming and/or circling, rapid opercular movements and abnormal skin pigmentation appeared in the form of skin fading. A marked decrease in RBCs, Hb content , PCV , MCV, MCH, MCHC and WBCs. where as, A significant increase in AST & ALT activities, creatinine, urea, uric acid, glucose, cortisol and serum Calcium levels were recorded . Furthermore, diazinon exposures were associated with an inhibition of cholinesterase activity, a decrease in total protein concentration in serum with a reduction in both albumin and globulin . Also the histopathological alterations of skin, gills, liver, kidney, spleen and brain of the exposed fish were recorded . The residual analysis of diazinon exposed C. gariepinus during the chronic exposure indicated that gills are the site of uptake, and muscles are the site of accumulation of such material. To know the degree of diazinon withdrawal from the exposed fish, a clearance test was carried out and the results revealed that diazinon withdraw was very slow. However this study declared that diazinon is an extremely toxic organophosphorous pesticide for C. gariepinus , its improper application often results in contamination of the environment and consequently in deleterious health effects. So, strict precautions should be followed during diazinon application to prevent its access into the aquatic system also agricultural drainage water used for pisciculture should be monitored for diazinon periodically.
Keywords: Diazinon, Freshwater fish, Clinical signs, Biochemical parameters, Blood parameters, Residual analysis.