This work was focused on study the ecosystem components, water, sediment, aquatic weeds and fishes in 4 locations at Manzala lake. Evaluation of ecosystem pollution was done by measuring the levels of organochlorine and organophosphorus insecticides. Organochlorine was significantly higher in water samples at ring road comparing with Port-Said Damietta Road, Bogaz El-resoah and finally at El-Gamel area (natural reserve area now). In sediment samples, organochlorine detected at Round and Port-Said Damietta roads. In aquatic weeds and fish muscles, the significant higher residue levels were detected in round word, followed by Port-Said Damietta and Bogaz El-Resoah (no fishing), then finally at El-Gamel area. From organophosphorus pesticides only Ethoprophos, Chlorpyrifos and Diazinon could be detected in some examined samples, tacking in consideration that only Diazinon in fish muscles fishing from ring road was exceeded the Maximum Permissible Level. This could be regarded to the relative short half life of organophosphorus comparing with organochlorine. Results of this study demonstrated that fish samples collected from Manzala Lake at three areas were contaminated with levels of organochlorine, not higher than maximum permissible level recorded by FAO/WHO and that public is not at risk from fish consumption, even that they totally dependent upon fish as only protein source.
This study proved the significant correlation between 4 studied areas at Manzala lake ecosystem components, water, aquatic weeds, sediment and fish. It's concluded that the major environmental impacts on Manzala Lake are due to direct drainage of untreated waste water, irrigation water from manufacture activities as well as land reclamation. These problems have contributed to a significant deterioration of water quality and subsequent other lake ecosystem.
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