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Abstract El-Wadi and El-Bats drainages considered the main reservoirs for agricultural and domestic non-treated drainage waters at El-Fayoum province, So the aim of the present field study is to provide comparable data between El-Wadi, El-Bats drainages and Hawara channel (a branch of the Nile river) with using Nile tilapia (Oreochromis niloticus) as indicator of natural and anthropogenic impacts on aquatic ecosystem. Results revealed highly significant differences among the studied parameters in water, sediment and Oreochromis niloticus fish collected from the studied sites of collection with an increase in values of ammonia, nitrite, heavy metals (Fe, Zn, Cd, Cu and Mn) and a decrease in dissolved oxygen content in water samples collected from the main drains (El-Bats and El-Wadi) when compared with Hawara channel. Results also revealed that mean value of Cd recorded the lowest concentrations between five heavy metals and slightly exceeded permissible limits, while Zn recorded the highest concentrations in Hawara channel. However, in El-Bats and El-Wadi Drains, Cd showed the lowest concentrations between metals and exceeded permissible limits and Fe showed the highest concentrations that exceeded permissible limits in great concern. The results revealed also highly significant increase of Serum ALT, AST, ALP and LDH activity as well as Creatinine, uric acid, Urea, lipid profile parameters (Triglycerides, Total lipids and Cholesterol) and protein profile parameters (Total protein, Albumin and Globulin) concentration in serum of Oreochromis niloticus collected from polluted drainages compared with that collected from Hawara channel. The comet assay test applied for hepatocytes of Oreochromis niloticus in the three studied sites for detecting DNA damage. Results revealed that the DNA strand breaks in fish liver cells increased statistically in Oreochromis niloticus collected from El-Wadi and El-Bats drainages compared with fish collected from Hawara channel, and this damage represented in terms of comet %, DNA % in tail, DNA % in head, tail length and finally tail moment. In addition, histopathological damage in gills, liver, kidney and muscles of Oreochromis niloticus collected from the drainage canals were recorded. Results of the present study reflect the ecological status of El-Fayoum drainages, deterioration of its water quality as well as fish stock that helps the policy maker to make effective decisions for proper management of the studied drainages. |