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 in water, 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.

easonal variations in the concentrations of four heavy metals; zinc (Zn), copper (Cu), lead (Pb) and cadmium (Cd), were determined in gills, skin and muscles of two fish species (Mugil cephalus and Liza ramada) from five locations in Lake Manzala. The average concentrations of the metals in fish tissues exhibited the following order: Zn>Cu>Pb>Cd. The statistical analysis revealed a significant effect of seasons, locations and fish tissues for all metals measured. The highest values of the metals were recorded in hot seasons (summer and spring). Fish samples from location V (Bahr El-Bakar) displayed the highest metal concentrations in their tissues. The highest concentrations of heavy metals were found in gills tissue of both fish species, while the lowest ones were recorded in muscles tissue. The values of the metals detected in the edible fish muscles were within the permissible limits.

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