Bioaccumulation of carcinogenic metals in river fish: A quantitative investigation of public health risk

[Display omitted] •The study provides a thorough quantitative examination of fish species from river Tawi for carcinogenic elements, such as Pb, Cd, and Cr.•Target heavy metals were found higher than the permissible limits in water and fish samples at all monitoring sites.•Present study discusses how eating such contaminated fish can cause cancer, especially in children, even when other health risks are low.•Immediate action must be taken to control the discharge of contaminated water into the river. There should be regular monitoring of the river's water quality. The rivers are severely contaminated by human activities due to its massive outflow and industrial effluents. Three economically significant fish species Sperata seenghala, Wallago attu, and Cyprinus carpio from the river water were selected for the assessment of heavy metals (HMs). The edible part of the collected fish from the river sampling sites were analyzed to determine the metal concentrations and potential health risks to humans. The Atomic Absorption Spectroscopy (AAS) technique was used to measure HMs including lead (Pb), chromium (Cr), and copper (Cu) for both water and fish samples. Order of HMs in the fish was found as Pb > Cd > Cr. Levels of HMs in all species were found higher than the European Commission (EC) recommended acceptable levels. The metal pollution index (MPI) indicates that W. attu and S. seenghala, two highly consumed fish species, have accumulated HMs in higher concentrations. Wallago attu has the highest bioaccumulation factor (BAF) for both Pb and Cd permissible levels. For adult and children, the Hazard Index (HI) and Targeted Hazard Quotient (THQ) values were less than 1, which indicated that there would be no non-carcinogenic health consequences. Carcinogenic risk (CR) exposure to Pb, Cd, and Cr for all consumers was found to be higher than the permitted limit (10−6-10−4), while children were found more vulnerable than adults in terms of CR values. The study findings identified several sources of contaminants in the area, including agricultural waste, lubricant usage, and electroplating material production dumping near into the river water. Based on the results of the analysis, metal concentrations exceeded the thresholds for carcinogenic health risks, indicating that fish from the area are generally unsafe to consume. Therefore, immediate action must be taken to reduce or prevent the discharge of contaminants into the river. Additionally, regular monitoring of