الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 312 |  |  |
| | | from | 312 | | |
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.
In addition, curling and separation were prevalent in secondary lamellae of all collected samples. The epithelial cells of primary and secondary lamellae showed severe degenerative and necrotic changes.
The changes in liver cells were characterized by degeneration, edema and necrotic areas occupied by remain of the cytoplasm. Also pyknotic nuclei were evident in some hepatocyte. In addition fibrosis, Parasitic forms, hemorrhage, hemolysis and hemosidrin pigments were observed in the hepatic cells. Degeneration, dilatation, branching and thickness in the wall of blood vessels besides to hemorrhage, hemolysis and hemosidrin in blood vessels were clear. Changes of kidney cells were detected as degeneration, necrosis, edema, fibrosis, parasitic forms, hemorrahage, hemolysis and hemosidrin pigment in kidney tubules. Besides degeneration, necrosis and fibrosis in the Bowman’s capsule and hematopoietic tissue were clear.
The changes in the spleen of collected fish were degeneration, necrosis, fibrosis, parasitic forms, hemorrhage, hemolysis and hemosidrin in spleenic tissue and blood vessels. In addition, aggregations of blood cells and hemosidrin pigments in necrotic areas were detected. Those alterations were observed in all five organs in all stations during all seasons but were severe in Talkha station and in hot seasons.