Seasonal variations of heavy metals contamination in sediment, water and crab at a vital fish sanctuary connected to the Bay of Bengal and health risk assessment

Andharmanik river is considered a fish refuge due to its unique habitat features, a natural mix of upstream freshwater and tidal exchanges with the Bay of Bengal. But the river is being polluted mostly by anthropogenic sources. This study highlights the first comprehensive effort to quantify heavy metal contamination in sediments, water and crab using ICP-MS, along with the associate health risk evaluation. The result showed that As, Co, Cr, Cu, Mn, Ni and Zn contents exceeded the recommended value in sediment. But, heavy metals content in water samples didn’t exceed the recommended value. In crab samples, metals like As, Cd, Cr, Cu, Fe, Pb and Zn had higher concentration than the recommended value. Meanwhile, the result of Risk Index (RI) indicated that sediment and water have no ecological risk. In crab, the value of total target hazard quotient (TTHQ) was higher than the acceptable limit of 1 depicting that the consumption of crab poses a carcinogenic risk for child and adult’s groups. Further, the Carcinogenic Risk (CR) value of Cr and Pb exceeded the threshold limit and suggested that there might be a significant health concern with prolonged exposure of contaminated crab for child ages. The findings indicated that the river ecosystem is contaminated by effluents from anthropogenic activities which need to be monitored to enforce environmental laws strictly for sustainable management.