Accumulation and human health risk assessment of trace elements in two fish species, Cirrhinus mrigala and Oreochromis niloticus, at Tarukri Drain, District Rahimyar Khan, Punjab, Pakistan.

The toxic discharge of heavy metals into the water affects the aquatic ecosystem as well as the human population interacting with it because of their toxicity, bioaccumulation, long persistence, and transfer through the food chain. Thus, it is very important to conduct studies to determine the level of heavy metal pollution in order to better control, manage, and preserve the pollution of aquatic ecosystems. This study assessed heavy metal contamination in fish and its associated health risk to the population around the Tarukri Drain, Punjab, Pakistan. Two fish species (Oreochromis niloticus and Cirrhinus mrigala) were collected from three different sites in two different seasons. Collected fish were analyzed for cadmium (Cd), iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) accumulation using atomic absorption spectrometer (AAS). Furthermore, the human health risks associated with the consumption of affected fish were also assessed. Target hazardous quotient for seasonal consumers was between 0.12, - 1.58 × 10, and 0.54 - 3.28 × 10 (mg/kg) in O. niloticus and C. mrigala, respectively. While for regular consumers it was between 0.28-3.71 × 10 and 1.27-7.68 × 10 (mg/kg) in O. niloticus and C. mrigala respectively for the studied heavy metals. Fish sampled from Sadiqabad contained the highest concentration of heavy metals. The analysis of fish organs (kidney, liver, and muscles) showed heavy metal accumulation in the order of kidney > liver > muscles (p < 0.00). The obtained results showed that heavy metal contaminations in both fish species were within the permissible limits recommended by the World Health Organization (WHO). Both sampling seasons (i.e., summer and winter) showed a non-significant difference in heavy metal concentration. The calculated total target hazardous quotient across all heavy metals remained < 1 with only one exception. The carcinogenic risk assessment of heavy metals showed a non-significant effect in both fish species.