Histopathology and heavy metal bioaccumulation in some tissues of Luciobarbus xanthopterus collected from Tigris River of Baghdad, Iraq

Abstract

The current study was undertaken to determine the histopathology and heavy metals content (lead and cadmium) in water and in fish samples caught from the Tigris River in Baghdad. The maximum means of aqueous metals (mg/L) were found at site 3 in the following order: Pb (1.25) > Cd (0.06) followed by site 2 Pb (1.04) > Cd (0.05). The results revealed marked differences (P < 0.05) in the two analyzed metal content among the three sites. Results showed that metal accumulation in fish tissue was detected in the following descending order: Pb > Cd. The general order of metals levels in different tissues are represented as follows livers > kidneys > muscles > gills. Most common livers lesions observed in Luciobarbus xanthopterus, in the polluted sites were cytoplasmic vacuolation, degeneration, and mononuclear cells infiltration. While kidneys from polluted sites exhibited detached epithelial cells from the basal lamina with hydrobic degeneration. Gills exhibited hyperplasia, lifting and necrosis of the secondary lamellae. These results present a good indicator for bio-monitoring of heavy metals pollution in the Tigris River. Hence, it is very important to make a comprehensive assessment of the hazards posed by these metals in other water bodies of the country.