Heavy metal pollution in commonly consumed fish species: seasonal variations and health risks

This study examined the concentrations of seven heavy metals (Pb, Cu, Zn, Cr, Cd, Ni, and Mn) in the muscle tissue of six commonly consumed fish species (Cyprinus carpio, Labeo rohita, Wallagu attu, Hypophthalmicthys molitrix, Channa punctuate, and Puntius sophore) from the River Indus in the Mianwali district Pakistan. Samples were collected during both pre-monsoon and post-monsoon seasons to assess the potential human health risks associated with these heavy metals. The levels of metals were measured using atomic absorption spectroscopic analysis. The results showed varying concentrations of heavy metals in the fish samples (mg/kg), ranging from 10.17-2.06 for Pb, 41.83-12.54 for Cu, 417.04-41.93 for Zn, 2.06-0.46 for Cr, 0.86-0.08 for Cd, 4.33-1.43 for Ni, and 50.16-8.74 for Mn. Notably, metal concentrations were generally higher during the pre-monsoon season, with Pb consistently exceeding standard limits in the muscle tissue of all fish species. ANOVA analysis revealed significant variations in heavy metal concentrations among different fish species. While the current consumption rate poses no significant health risks, ongoing monitoring of heavy metal concentrations in fish and their environmental sources is crucial to ensure consumer safety and sustainable aquatic ecosystems.