Spatiotemporal variation and potential risks of seven heavy metals in seawater, sediment, and seafood in Xiangshan Bay, China (2011-2016)

The residues and risks of heavy metals in the environment and organisms have attracted great concern for many years. However, the information on their long-term spatiotemporal trends and potential health and ecological risks are scarce. In this study, a total of 1815 seawater samples, 451 sediment samples, and 54 seafood samples were collected in Xiangshan Bay, China, between 2011 and 2016. The residue, distribution, seasonal variation, and potential health risks of seven heavy metals in seawater, sediment, and seafood were evaluated. Dissolved Zn (mean = 16.8 μg L−1) and Cu (mean = 3.4 μg L−1) concentrations were high in seawater. Sediments were mainly contaminated by Zn (mean = 120.8 mg kg−1) and Cr (mean = 81.7 mg kg−1). The highest levels of Cu and Zn were observed in Ostreidae with the concentrations of 84.3 and 99.0 mg kg−1, respectively. The Kendall test indicated that only As, Cu, Cd, and Hg showed decreasing trends in seawater with time and no significant temporal trends were identified for heavy metals in sediment between 2011 and 2016. Only As may pose non-carcinogenic risks to both adults and children in some seafood. These data provide a reliable reference for government to use in developing reasonable and scientific regulations on the ecological and food safety of this area.