Mining, waste disposal, and fossil fuel combustions are key factors that are polluting the aquatic environment rapidly. Bioaccumulation and toxicity of heavy metals are major problems of the aquatic environment which change the physicochemical properties of water which is hazardous for aquatic organisms especially fish because heavy metals develop oxidative stress in fish bodies.   

This study was designed to determine the levels of heavy metals cadmium, nickel, arsenic, and lead in the liver and gills of two most important edible fish species; Cirrhinus mrigala and Bagarius bagarius, taken from the Jhelum River district Khushab, Punjab, Pakistan. In the current study, to check the presence of heavy metals the process of wet/acid digestion was implemented to prepare samples of fish liver and gills then the prepared samples were analyzed using an atomic absorption spectrometer. Heavy metal lead was recorded in the highest amount in the gills of Cirrhinus mrigala and Bagarius bagarius with the values (0.69µg/g) and (0.77µg/g) respectively. The order of heavy metals examined in the gills of Cirrhinus mrigala was Pb>Ni>As>Cd. The sequence of heavy metals examined in the gills of Bagarius bagarius was Pb>As≥Ni>Cd. Heavy metal nickel was recorded in the highest concentration in the liver of Cirrhinus mrigala (0.63µg/g) and in Bagarius bagarius arsenic concentration was highest with the value of (0.56µg/g). The order of heavy metals examined in liver of Cirrhinus mrigala was Ni>Cd>As>Pb while the sequence of heavy metals examined in the liver of  Bagarius bagarius was As>Ni>Cd>Pb. Overall, all the heavy metals values were exceeding the WHO limits imposing an alarming situation. Bioaccumulation of such heavy metals in fish is dangerous because when humans consume contaminated fish on regular bases they also bioaccumulate heavy metals which may lead to different health issues, particularly endocrine disruption. Proper disposal of waste and recycling along with chemical precipitation and ion exchange are some measures to avoid harmful consequences of heavy metals contaminations.

Keywords- Bio-accumulation, Bagarius bagarius, Cirrhinus mrigala, Heavy metals