Water quality and heavy metals monitoring in water and tissues of Nile tilapia fish from different governorates "Egyptian Aquaculture farms"

All aquatic organisms are directly or indirectly affected by the physico-chemical characteristics of their environment, especially the chemical composition of the water, where it is the main factor affecting the cultured fish. So, the present study investigated the quality of water ponds and their impacts on fish reared in three different farms at Sahl El-Hussaynia, Sharkia governorate, Kafr El-Sheikh, governorate and at Sahl El-Tinna, Port-Saeed governorate, Egypt. Water and fish samples were taken during summer to evaluate the physico-chemical characteristics and heavy metals distribution in water and fish tissues (muscles, gill and liver). Moreover, the effect of accumulated heavy metals on glucose, total proteins and the activities of transaminases (AST and ALT) in the fish muscles was studied.Also, Physical and chemical characteristics of water (water temperature, pH, DO, NH₃, No₃, total alkalinity, total hardness and phosphate) were measured.
Heavy metals varied depending upon the organs and location. Also, the order of occurrence of heavy metals in water ranked at the following order; Zn> Fe> Cu> Cd at Sahl El-Hussaynia and Sahl El-Tinna farm but at Kafr El-Shiekh farm the order was Fe> Zn> Cu> Cd. Pb metal was not detected in the three farms. In the same time, the heavy metals were found in muscles, gills, and liver in the order Fe> Zn> Cu in the three fish farms, but Pb and Cd were not detected. In the liver, levels of the heavy metals exceeded the permissible limits according to WHO (1989). Moreover, in gills the levels of Zn exceeded the permissible limits at El–Hussaynia and Kafr El-Shiekh farms, but in muscles didn't exceed the permissible limits, except the Fe. The results of glucose, total protein, and activities of AST and ALT had some fluctuations in the serum among the studied fish.