he levels of some heavy metals (Cu, Zn, Cd, Pb) were determined in water,plankton and fish (Liza aurata) collected from five sites in Lake Manzala. Metals in water and fish exhibited a significant seasonal and regional variations
in which all metals attained their maximum values during summer, while the lowest level was reported during winter. The accumulation of different metals inwater, plankton and fish tissues followed the order Zn> Cu> Pb> Cd. The mean
concentrations of the tested metals in water were: Cu (0.055), Zn (0.311), Cd (0.020) and Pb (0.022) mg/l. Cd level in water was found to be higher than the permissible limit recommended for drinking water. Metals in plankton were
much higher than those in water and fish. Gills of the examined fish contained the highest concentrations of all the measured metals, while muscles retained the lowest levels. In spite of the contamination of Lake Manzala by such heavy
metals, the levels of these metals in the edible fish muscle did not exceed the recommended permissible limits and thus are considered safe for human consumption.