الفهرس 
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Abstract
A total of 300 fish samples (100 for each of Nile tilapia, Flat head grey mullet and African cat fish) of different weights were freshly collected from Manzala Lake during summer and winter of 2012 and analyzed using flame atomic absorption spectrophotometer for detection of Lead (Pb), Mercury (Hg), Cadmium (Cd) and Arsenic (As). The mean concentrations of Pb, Hg, Cd and As were 0.704 µg/g, 0.045 µg/g, 0.025 µg/g and 0.511µg/g for Nile tilapia, 0.635 µg/g, 0.0145 µg/g, 0.006 µg/g and 0.621 µg/g in Flat head grey mullet and 0.64 µg/g, 0.017 µg/g, 0.020 µg/g and 0.568 µg/g in African cat fish. The highest Pb,Hg and Cd concentrations found in Nile tilapia˂ African cat fish˂ Flat head grey mullet. While the highest As concentration found in Flat head grey mullet˂ African cat fish ˂ Nile tilapia. The estimated daily intake (EDI) did not exceed the permissible tolerable daily intake (PTDI) in normal fish consumers as fishermen but the EDI may exceed the PTDI in high fish consumers as fishermen. By assessing the THQ it was found to be less than 1 for all tested metals in the three fish samples indicating that there was no significant puplic health hazard except for As which exceeded 1 indicating a significant health hazard. Also HI exceeded 1 in all analyzed metals in the three fish species indicating a significant puplic health hazard on the consumers of these fish species from Manzala lake. There was a significant negative correlation between fish weight and both Pb and Hg concentrations, On the other hand there was a positive correlation between fish weight and both Cd and As concentrations.