Bioaccumulation of metals in aquatic species from anthropogenically stressed and ecologically sensitive zones of Maharashtra's coastal belt, India

Edible aquatic species are an essential component of the human diet and contain nutrients that are required for normal metabolism and the growth of the human body. However, aquatic species, due to their surrounding environment, can also lead to the bioaccumulation of non-essential elements that may pose a serious threat to human health upon consumption. Therefore, the present study is an attempt to understand the variation in bioaccumulation of essential metals (Mn, Co, Cu, Zn, Cr, Se, and Sr) and non-essential metals (As, Pb, Cd, Sb, and Sn) within 19 locally consumed fish in two different regions of the western coast of Maharashtra, India. The assessment of aquatic species showed significantly higher bioavailability of non-essential metals in the North-west region (NW- Mumbai), which is anthropogenically stressed due to industrial effluents, domestic discharges, dredging activities, and land runoffs. On the contrary, lower accumulations of non-essential metals were observed in the South-west region (SW- Malvan), having insignificant sources of anthropogenic activities. The metal pollution index (MPI) was higher by 40 % in the NW region than the SW region of Maharashtra. The health risk assessment indicated the mean estimated daily intake (EDI) for As and Pb found in Mumbai samples were 42 % and 25 % higher than tolerable daily intake (TDI), respectively, whereas for the Malvan region, both metals were in the acceptable TDI. The EDI for Cd, however, was higher by 251 % and 61 % than the TDI levels in Mumbai and Malvan, respectively. The target carcinogenic risk (TCR) for As in Mumbai and Malvan was 4.57 × 10⁻⁰³ and 1.70 × 10⁻⁰³, while for Cr it was 2.95 × 10⁻⁰³ and 1.33 × 10⁻⁰³, respectively. This was above the TCR guideline of 10⁻⁰⁴ (indicating cancer risk over a human life as 1 in 10,000). In crux, the health risk assessment indices disclosed that As, Cd, Pb, and Cr in the analysed fish species might have toxicological effects upon chronic uptake and can impair community health.