Water and catfish samples were collected from two main drainage canals in El-Fyoum Governorate (El-Bats and El-Wadi) and from Wadi El-Rayan lake where effluents of El-Wadi drain mixed with Bahr Yousef fresh water, branch of the river Nile, discharged directly. Fish were subjected to different analyses in comparison with fish transferred from El-Bats drain and reared in dechlorinated tap water in laboratory for a week. Quality of water samples collected from the different studied ecosystems, revealed a significant increase in ammoni, nitrite, copper, lead, cadmium, lindane and aldrin of the studied drainage canals water (El-Bats and El-Wadi) than that collected from Wadi El-Rayan Lake. Fish collected from the El-Bats drainage canal bioaccumulated heavy metal (Pb, Cd and Cu) and pesticides (Lindan and aldrin) in gills, liver and muscles much higher than that collected from El-Wadi drain. Moreover, fish collected from the drainage canals showed highly significant differences at P< 0.01 with the lowest RBCs, Ht, Hb, total protein, total lipids but highest methaemoglobin level, serum glucose level, creatinine, uric acid contents as well as the activities of AST and ALT in comparison with those of fish collected from Wadi El-Rayan Lake. However, fish collected from El-Bats drainage canal and reared in dechlorinated tap water for a week revealed recovery in all studied parameters to normal levels as well as fish collected from Wadi El-Rayan lake that exposed to agricultural drainage water mixed with Bahr Yousef fresh water. Therefore, solutions have to be found; otherwise the virgin wetland, Wadi El-Rayan Lake, will face pollution problems similar to those of Lake Qarun where El-Bats drain discharged directly without any treatment.
Key words: Catfish, Wadi El-Rayan Lake, Drainage effluents, Ecotoxicological recovery
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