Assessment of seasonal and spatial variations of heavy metals in the muscles of Oreochromis niloticus and Clarias gariepinus at Sharkia province, Egypt: Biochemistry and Histology Evaluation

The most significant pollutants are the heavy metals in the aquatic network due to their toxicity, accumulation, and bio-magnification. In an attempt to characterize the physical-chemical and demonstrate the potential water impact of the heavy metal content of wastes in two lakes in Sharkia province, Egypt, this study was developed to determine their toxicity and the potential waste impacts in biochemistry and histology of fish muscle. Samples of water and fish muscles were collected and analyzed for heavy metals using atomic absorption of two different fish species (Oreochromis niloticus and Clarias gariepinus) along two canals in Sharkia province in Egypt during the four seasons in 2018. The water samples were also analyzed for the physicochemical parameters. The impact of heavy metal on the enzymatic antioxidant (superoxide dismutase and catalase) as well as the reduced glutathione content, besides the oxidative stress marker presented by lipid peroxidation levels in fish muscles, were evaluated. Results showed the largest amount of chloride (Cl-) and iron (Fe) in the Sharkia water sample, while Faquas water sample had the highest level of HCO3 and iron (Fe). The manganese concentration in the fish muscle was the highest in Sharkia water and the highest level of Fe was detected in the fish muscles collected from Faquas area. These high levels of some of the physicochemical parameters and heavy metals in the two lakes with two different wastes as seen in this study may be a source of water pollution. The highest accumulation of metals in the muscle of the two fish species, suggesting risk for human consumption. There were seasonal variations in the level of LPO in muscle tissue of two types of fishes with a reverse relationship with antioxidant parameters. This accumulation varied seasonal and spatial as well as according to the species of fish. Increasing the level of heavy metals effect on the biochemistry and histology of fish. Keywords: Heavy metals; Muscle; Oxidative/Antioxidant, Histology, Clarias gariepinus; Oreochromis niloticu