Bioaccumulation and health risk of metal contamination from different tiers of food chain in Ennore estuary, Southeast coast of India

Abstract

The concentration and bioaccumulation of heavy metals were investigated in four distinct components (water, sediment, benthic organisms, and fish) in the Ennore estuary. The average concentration of studied metals in water is 2-5 times higher in the sediment. The geoaccumulation index in the sediment, particularly for Cd, 55 folds greater than WHO and USEPS standards. The indices like MI, C_deg, PLI, and PERI demonstrated low contamination levels, whereas I_geo and C_f revealed elevated levels of cadmium (Cd), signifying a moderate degree of contamination. Human health indices like Target Hazard Quotation (THQ) values generally fell within permissible limits (<1), except for lead (Pb) and iron (Fe). However, HI values exceeded 1, indicating a non-carcinogenic health risk for consumers. The Target Risk for lead (TR_Pb) value for Oreochromis urolepis was 1.0 × 10^-5, suggesting a significant cancer risk and may leads to other fish species in future if carcinogenic metals bioaccumulation.

Keywords: Bioaccumulation; Health risk; Heavy metal; Pollution indices; Target risk.