The impact of feeding pattern on heavy metal accumulation and associated health risks in fishes from the Dhaleshwari River Bangladesh

Heavy metals in aquatic ecosystems accumulate in fish tissues, posing significant ecological and health hazards due to their toxic effects on both the environment and human consumers. The purpose of the study was to assess the potential hazards associated with consuming carnivorous, omnivorous, and herbivorous fish species from the Dhaleshwari River in Bangladesh. The study focused on the seasonal variation and accumulation pattern of toxic heavy metals in these fish species. For this, four fish species (Wallagu attu, Ompak bimaculatus, Labeo calbasu, Cirrhinus mrigala were sampled during the dry and wet seasons from the contiguity of the industrial outlet from Dhaleshwari River. The amount of accumulation of Cr, Pb, Cd, Cu and As in the muscles of the samples were analyzed using spectrophotometry. Heavy metal concentrations were observed to be in the following descending order: Cu (1.99) > Cr (1.92) > Pb (1.42) > Cd (0.31) > As (≤0.0002) (mg/kg, wet weight). Cr, Cd and Pb concentrations exceeded some international food safety guidelines for fish muscles. Carnivorous species exhibited higher metal accumulation than omnivores and herbivores. Statistical analysis revealed significant variations among seasons (p < 0.001), species (p < 0.05) and strong correlation among metals (except As) with p < 0.01. Risk assessment suggested carnivorous species might pose noncarcinogenic risks to both of its child and adult consumers. Despite the potential noncarcinogenic risks, the alarming levels of chromium in these fish indicate a substantial cancer risk for both adults and children, raising concerns about the safety of consuming fish from the Dhaleshwari River. These findings strongly emphasize the importance of implementing enhanced regulatory monitoring to mitigate health risks associated with contaminated fish consumption.