The study is carried out at 5 stations along Damietta branch of the River Nile. Some Physico-chemical parameters (water temperature, electrical conductivity, pH value, oxygen studies, nutrient salts) and distribution of some heavy metals (iron, zinc, copper, cadmium and manganese) in water were determined seasonally from spring 2012 to winter 2013. Fish analysis included the study of heavy metals accumulation in some organs of fish and histopathological changes in some organs of Oreochromis niloticus fish. The present results showed an increase in EC, DO, BOD, ammonia, Nitrate, Fe and Mn at down Talkha Electrical power station. On the other hand, an increase of Fe, Zn and Cu in kidney, and of Mn in gills and of Cd in muscles was recorded. The detected pathological alterations of O. niloticus skin and muscles were degeneration and necrosis in the epithelial layer cells leading to complete rupture or loss of layer. Besides, hemorrhage, hemolysis, hemosidrin accumulation, degeneration and necrosis in epidermal, dermal, hypodermal layers and muscle layers. Parasitic forms were observed in muscle fibers layer in Benha and Talkha stations. Pathological changes in gills were severe and included hyperplasia of primary and secondary lamellae. Meanwhile severe hemorrhage, hemolysis and hemosidrin accumulation in primary and secondary lamellae of the gills were obvious.

Abstract

The study is carried out at 5 stations along Damietta branch of the River Nile. Some Physico-chemical parameters (water temperature, electrical conductivity, pH value, oxygen studies, nutrient salts) and distribution of some heavy metals (iron, zinc, copper, cadmium and manganese) in water were determined seasonally from spring 2012 to winter 2013. Fish analysis included the study of heavy metals accumulation in some organs of fish and histopathological changes in some organs of Oreochromis niloticus fish. The present results showed an increase in EC, DO, BOD, ammonia, Nitrate, Fe and Mn at down Talkha Electrical power station. On the other hand, an increase of Fe, Zn and Cu in kidney, and of Mn in gills and of Cd in muscles was recorded. The detected pathological alterations of O. niloticus skin and muscles were degeneration and necrosis in the epithelial layer cells leading to complete rupture or loss of layer. Besides, hemorrhage, hemolysis, hemosidrin accumulation, degeneration and necrosis in epidermal, dermal, hypodermal layers and muscle layers. Parasitic forms were observed in muscle fibers layer in Benha and Talkha stations. Pathological changes in gills were severe and included hyperplasia of primary and secondary lamellae. Meanwhile severe hemorrhage, hemolysis and hemosidrin accumulation in primary and secondary lamellae of the gills were obvious.