Pathological impacts of environmental toxins on oreochromis niloticus fish inhabiting the water of Damietta branch of the River Nile, Egypt

Abstract

The present study was carried out at El-Kanater El-Khayria & Talkha stations, Damietta branch of the River Nile. The concentrations of heavy metals (iron, zinc, copper, cadmium and manganese) in water and their accumulations in organs (muscles, gills, liver and kidneys) of Oreochromis niloticus fish were determined seasonally during year 2016. Also, the histopathological alterations in the same organs of selected fish samples were studied during the same year. The obtained results showed an increase in heavy metals concentrations in water collected from investigated area and these concentrations followed an abundance of: Fe > Mn > Zn > Cu > Cd. These metals accumulated in some organs of the studied fish and caused histopathological alteration in these studied organs. The histopathological alteration included degeneration, necrosis, edema, hemorrhage, hemolysis, hemosiderin, parasitic forms and hyperplasia in selected organs. Those changes were observed in all studied organs at the two stations during the period of study with severe degree at Talkha station during hot seasons. So, it is necessary to treat the polluted water before its discharging into the Damietta branch to protect fish and human beings from the dangers of pollution.