Heavy Metal Contamination in Macrobrachium rosenbergii From the Khulna Division of Bangladesh: A Human Health Risk Assessment.

This study aimed to determine the concentrations of heavy metals (As, Cr, Cd, Pb, and Hg) in Macrobrachium rosenbergii from prawn farms in Khulna division, Bangladesh, and to assess the associated human health risks. Twenty-four farms in different upazilas of Khulna division were selected for sampling, and heavy metal concentrations in prawns were determined using inductively coupled plasma mass spectrometry (ICP-MS). Metal concentrations varied among farms, with As ranging from BDL (below detection limit) to 1.475 mg/kg, Cr from BDL to 3.5 mg/kg, Cd from BDL to 0.091 mg/kg, Pb from BDL to 0.236 mg/kg, and Hg from BDL in all samples. The highest values of As, Cr, Cd, and Pb were observed in the Bagerhat district. Comparison with national and international standards (MOFL, FAO, WHO, and EC) showed that Cd and Pb were within permissible limits across all sites, whereas As and Cr concentrations exceeded the recommended limit in several locations. The results showed clear spatial variations in heavy metal accumulation driven by local anthropogenic activities such as aquaculture practices, agricultural runoff, and environmental inputs. Estimated daily intake (EDI) values revealed that children are more vulnerable than adults, with As and Cr contributing the highest dietary intake and remaining below the recommended health-based guidance values. Tabulated values of noncarcinogenic risk assessment indicators (THQ and HI) revealed potential cumulative noncarcinogenic health risks for children compared to adults, with HI values exceeding the safety threshold (HI > 1) at seven locations for children while all HI values for adults were below this limit. Target cancer risk (TR) assessment demonstrated that As and Cr were the major contributors to the estimated carcinogenic risk, whereas Cd and Pb generally showed comparatively lower contributions. Multivariate analysis revealed associations among heavy metals and spatial patterns in metal distribution, showing similar distribution patterns among Cr, Cd, and Pb, while As exhibited a distinct spatial behavior across the study area. The findings of the study therefore emphasize the importance of continuous monitoring, improved aquaculture management, and effective regulatory interventions to ensure food safety and protect public health by minimizing heavy metal exposure.