Ecological risks and concomitant health risk assessment of heavy metals in the surface water and sediment samples of Hatiya Island, Bangladesh

ABSTRACT Heavy metals in riverbed sediments and surface waters pose significant environmental and health risks due to their toxicity and bioaccumulation. This study analyzed sediment and surface water samples to evaluate heavy metal concentrations, sources, and associated health risks. Results showed that sediment concentrations followed the order Mn > Cu > Cr > Ni > Pb > Zn > Cd, while in water, the order was Cr > Cu > Ni > Zn > Mn > Pb > Cd. Sediment quality assessments using enrichment factor (EF), geo-accumulation index (Igeo), pollution load index (PLI), and contamination factor (CF) revealed notable accumulation of Cd. Water quality, evaluated by the heavy metal pollution index (HPI), indicated significant impairment by Cd and Ni. Health risk assessments, including hazard index (HI) and hazard quotient (HQ), suggested negligible non-carcinogenic risk (HI < 1), but dermal exposure to Cr, Cd, and Ni posed carcinogenic risks exceeding the acceptable threshold (10⁻⁴). Statistical analysis highlighted positive correlations among Cu, Zn, and Cr in both water and sediment. Field surveys identified local pollution sources, including metallurgical activities, fishing boats, and ship oil leaks. These findings are crucial for regional environmental monitoring and for protecting human health.