Trace metal accumulations in commercially important fish and crab species from impacted tropical estuary, India: implications on human health risk assessment.

Despite the beneficial role of aquatic food, bioaccumulation of trace metals can increase health risk for consumers. We conducted a comprehensive study to understand the levels of various trace metals (Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn and Mn) in fish (Nematalosa nasus, Gerres filamentosus, Arius arius, Gerres erythrourus, Sardinella fimbriata, Caranx ignobilis, Etroplus suratensis, Mugil cephalus, Sillago sihama, and Euryglossa orientalis) and crab (Portunus pelagicus and Scylla serrata) species collected from Netravathi-Gurupur estuary, India and evaluated the potential health risks to humans by measuring target health hazard (THQ), hazard index (HI), estimated daily (EDI) and weekly (EWI) intake and cancer risk (CR). The hierarchy of toxic metal content in studied species was Fe>Pb>Cr>Mn>Zn>Cu>Ni>Cd>Co. The concentration of heavy metals were distinctly lower than the threshold value as suggested by World Health Organization and Food Safety and Standards Authority of India, except for Cr and Pb in few species. THQ values were below the acceptable limit. However, the estimated mean HI values were >1 for children, indicating they may be vulnerable to health risk due to continuous consumption of contaminated aquatic species from the study area. In contrast, the cancer risk for Cr, Cd, and Pb was below the acceptable range. Principal component analysis (PCA) discerned nearby petrochemical industry, electroplating industry, pesticides and fertilizer from agricultural runoff, as the potential sources of metal bioaccumulation in different tissues. Although the study reveals that metal contamination in aquatic species does not pose any immediate human health effect, continuous monitoring of the study area is recommended, as some metals have demonstrated their ability to accumulate in the tissues.