Heavy metal contamination risk assessment of commercial fish in China's Dongting Lake

Rapid urbanization, industrialization, and intense agricultural practices in the cities and communities along the rivers have resulted in potentially toxic elements, such as heavy metals, being released into the river water and subsequently deposited into Dongting Lake, thereby posing a severe threat to fish, invertebrates, and humans. In this work, eight fish species, representing different kinds of feeding habits and living habitats, were collected from Dongting Lake, China. The concentration of heavy metals in the specimens was determined. Parameters related to fish consumption, such as food safety and health risks, were calculated. In descending order, the average heavy metal concentrations in the fish followed the trend: Zn>Cu>Pb>Cr>Cd>Hg. Moreover, some species of fish have concentrations of Cd and Pb that exceed food safety standards. The concentration of distinct heavy metals varied widely, but the total concentration trended as follows: predatory, omnivorous > filter > herbivorous, benthic > pelagic fish. The hazard quotient and hazard index values were < 1 for all trophic levels of fish, suggesting that consuming the muscle from fish retrieved from Dongting Lake may not present a potential human health risk to adults in terms of heavy metal contamination. Nevertheless, we recommend that Cyprinus carpio, Carassius auratus, and Silurus asotus should be consumed less, and that pollution prevention and control measures should be implemented to reduce Pb, Cd and Cr pollution.