Alterations in Antioxidant Defense System and Biochemical Metabolites in Fish from Rosetta Branch of The River Nile as a bio-Indicator of Environmental Pollution

Abstract

The aquatic environment and its water quality are considered the main factor controlling the state of health and disease in fishes. Pollution of the aquatic environment by inorganic and organic chemicals is a major threat to the survival of fish O. niloticus. Monitoring Water quality has one of the highest priorities in environmental protection policy. The River Nile water is facing rising sources of pollution, as it receives a large quantity of industrial, agriculture and domestic wastewater, Rosetta Branch of River Nile is the most polluted part of River Nile. It is about 220 Km length and about 180 m width with average depth 2.0 to 2.3 m. It starts from EL-Qanater EL-Khayria and ends at Rosetta Estuary. The physico-chemical characteristics of the aquatic environment directly influence the life inhabiting it. Fluctuations in these constituents create an adverse environment to organisms, limiting their growth and interfering in the physiological processes. Among aquatic pollutants heavy metals regard as serious pollutants of aquatic ecosystem because of their environmental persistence and toxicity, the most commonly heavy metals in waste water are (arsenic, cadmium, chromium, copper, lead, nickel, and zinc), Heavy metals are dangerous because they bioaccumulate in fish, which may cause biochemical and morphological alterations, also causes changes i