Distribution of organochlorine pesticides in the Egyptian aquatic ecosystem

The distribution of organochlorine pesticides among the major components of the Egyptian aquatic ecosystem (fish, water and sediment) were studied to explore the effect of sampling area, season, and fish species. The samples were collected from two catching areas that represent two different models of the aquatic ecosystem (El-Malek-El-Saleh and Manzala lake). Data showed that DDT and its analogues were predominant in fish samples collected from Manzala lake. On the other hand, total DDT followed by heptachlor were predominant in fish samples collected from the River Nile. The same organochlorine pesticides were found in water samples collected from Manzala lake and the River Nile during the two seasons, Winter and Summer. The concentrations of pesticides in samples from the River Nile were lower than those from Manzala lake. Pesticide residues detected in sediment samples from Manzala during Winter and Summer, followed the same descending order: total DDT > heptachlor > aldrin > lindane > gamma chlordane > β−BHC during the two seasons. During Winter, total DDT predominated in all the samples, analyzed from the River Nile, followed by heptachlor, aldrin, γ-chlordane, β-BHC and lindane. Meanwhile, during Summer, residues were found in the following descending order: total DDT > heptachlor > β-BHC > γ-chlordane > aldrin > lindane.