Ecotoxicological studies. 3. Heavy metals contaminating water and fish from Fayoum Governorate, Egypt

The distribution of some heavy metals in water and fish from Fayoum Governorate (Egypt) was studied in samples collected throughout two successive years (1997/1998 and 1998/1999). Water from Lake Qarun, a private fish farm and "Sanhour River" was found to contain heavy metals at concentration levels lower than those found in fish from the first two ecosystems. The heavy metals showed differential bioaccumulation in fish organs (e.g. flesh, head, viscera), and the accumulation pattern (as total heavy metal residues) was seasonally as follows: summer > autumn > winter > spring. Moreover, the relative accumulation of total heavy metals in the studied fish showed the following pattern: "Mousa fish" (Solea aegyptiaca) < "Bolti fish" (Tilapia sp.) < the shrimp (Penacus sp.) < "Bouri fish" (Mugil sp.). Among the analyzed metals (e.g. zinc, iron, manganese, copper, cadmium, chromium, nickel, lead, cobalt, tin), lead and cadmium were found in fish at mean concentrations above the permissible limits proposed by FAO. (C) 2002 Elsevier Science Ltd. All rights reserved.