Heavy metals in pelagic and benthic marine fish from Plymouth, UK, and associated human health risk assessment

Fish consumption is a significant pathway for toxic heavy metals to enter the food chain, posing risks to both aquatic ecosystems and human health. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine heavy metal concentrations in fish species. The highest concentrations (mg/kg) of Al (6.60); Ag (0.028), Cr (2.97) and Fe (37); Ba (0.40), Se (3.7) and Si (3.2); Cu (1.5); Mn (5.3), Ni (0.28) and Pb (0.88); and V (0.094) and Zn (13) were detected in megrim, ling, sand sole, thicklip grey mullet, common sole, lemon sole, Greenland halibut and European flounder, respectively. However, Cd and Co in all analysed fish species were below the limit of detection (LOD). Significant differences (p-values <0.05) were observed between pelagic and benthic fish feeders for Fe and V. The contents of heavy metals in both benthic and pelagic fish samples were below the maximum limit (ML) established by the World Health Organization (WHO) and European Food Safety Authority (EFSA). From a health point of view, the hazard quotient (HQ) values for the measured Al, Ag, Ba, Cu, Mn, Ni, Pb, Fe, Se, Si, V and Zn in both pelagic and benthic studied fish were below the established United States Environmental Protection Agency (USEPA) threshold of 1. However, Cr exhibits relatively higher HQ values compared to other elements, especially in ling and megrim across age groups. The hazard index (HI) values for all analysed fish species were generally below the established USEPA threshold of 1, except for ling, megrim, common sole (except for 15-18 years old and adults), sand sole and Greenland halibut (only for 1.5-4.5 years old). This indicates that individuals consuming these fish species may be at risk of non-carcinogenic health effects. Cancer risk (CR) values for Cd, Pb and Ni were within acceptable limits, but Cr in ling fish samples exceeded the established USEPA safe threshold of 1.0E-4 for adults.