| Abstract: |
Summary:-The present study investigated the effects of four commonly usedpesticides, namely Reldan (chlorpyrifos-methyl) and Seliton (profenofos) onOreochromis niloticus which they are organophosphorus insecticides and Saturn(thiobencarb) which is carbamate herbicide and Roundup (glyphosate)(organophosphorus herbicides) on cyprinus carpio.1. Toxicity of Reldan (chlorpyrifos-methyl) on Oreochromis niloticus.1.1. Acute Toxicity of Reldan on Oreochromis niloticus .• Mortality rate of Oreochromis niloticus which exposed to different doses ofReldan recorded 0, 20, 30, 40, 60, 80, 90 and 100% at concentration 0.6,0.8, 1.4, 1.6, 2.4, 3.2, 3.8 and 4 mg/L of Reldan respectively. The lethalconcentration-50 (96 hrs LCso) was 2.28 mg/L of Reldan during 96 hrs.• Clinical signs: abnormal swimming movement, convulsion and jumpingabove water surface.• Postmortem: Congestion of all internal organs and gills.• Some blood parameters of fish: Blood samples collected after 96 hrs ofexposure show decrease in RBCs, PCV and Hb and increase in WBCs,creatinine, urea, SGOT, SGPT, blood sugar and cortisol.• Histopathological findings: Liver shows numerous eosinophilic granularcells in hepato-portal area and hyDROPic degeneration of some hepatocytesand necrosis of some gill filaments.1.2. Chronic toxicity of Reldan:The result of mortality rate of fish exposed to 1110 (0.228 mg/L) and 1120(0.114 mg/L) LCso of Reldan for 8 weeks were 26.6 % and 16.6 % respectively.
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