Bioaccumulation of heavy metals in seafood resources from the southwest coast of India: human health risk assessment and importance of seafood security

The present study was to evaluate the bioaccumulation of heavy metals and possible human health risk from contaminated seafood resources from the Cochin Estuarine System, Southwest coast of India.

Water, sediment, fish, and shellfish samples were collected from the Cochin Estuarine System during the monsoon and non-monsoon period and were analyzed for heavy metals. Human health risk from contaminated fishes was analyzed using deterministic and probabilistic risk assessment methods.

Water, sediment, and biota exhibited elevated concentrations of heavy metals during non-monsoon periods. Zinc was the most abundant metal, while cadmium had the lowest concentration among the three mediums. The presence of cadmium in the estuary posed a moderate to very high ecological risk. Zinc, cadmium, and chromium exceeded the toxicity threshold outlined in the sediment quality guidelines. All metals except cadmium showed significant variation between species and season (p < 0.05). Chromium and zinc correlated positively with fish size, while Cu, Cd, Mn, and Ni showed a negative correlation (p < 0.05). Chromium had the highest accumulation in herbivores, and Cd was highest in filter feeders. Cadmium and lead exceeded the standards of the Food Safety and Standards Authority of India and the Food and Agriculture Organization. The estimated daily intake and target hazard quotient of individual metals were found to be very low. In the Monte Carlo simulation, the 95th percentile of the hazard index (0.80) indicates that consumers are close to experiencing non-carcinogenic health risks. The cancer risk for cadmium (2.15E−3) and chromium (3.90E−4) suggests that consumers may be vulnerable to long-term risk. Cadmium was found to be the most influencing metal in the risk analysis.

The results indicate the need for regular monitoring and risk assessment of heavy metals, especially lead, cadmium, and chromium, in seafood resources across coastal areas to ensure food security.