الفهرس 
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Abstract
Eel (Anguilla anguilla) performs a good source of hard cunency, it meets a great demand in many European countries, meanwhile, it is highly esteemed by the Egyptian people. European eel mainly inhabits the four northern delta lakes; Mariut, Edku, Brollus and EI-Manzalah, as well as Nozha Hydrodrome and the Nile estuaries. Recently, eel density in fresh and brackish waters has been reduced owing to: . Decrea:)ing numbers of elvers which enter the lake from the sea for feeding. . Decreasing areas of lakes as a result of land reclamation. . The influence of acute pollution. Eel can often be exposed to various pollutants in marine, brackish and fresh waters at each life cycle stage. Among the various pollutants, some heavy metals such as cadmium, chromium and lead are known to be toxic even at low concentrations, some others, i.e. copper and zinc are essential heavy metals and are required metabolically at very low concentrations.