Interannual variation, ecological risk and human health risk of heavy metals in oyster-cultured sediments in the Maowei Estuary, China, from 2011 to 2018

Heavy metals (HMs) in aquaculture-influenced sediments pose a threat to both aquatic ecosystems and human health via aquatic product intake. Based on a long-term (from 2011 to 2018) study, the concentrations of five HMs in oyster-cultured sediments in the Maowei Estuary, China, were ranked as follows: Pb (17.58 +/- 10.82 mg/kg) > Cu (17.15 +/- 8.61 mg/kg) > As (10.27 +/- 5.24 mg/kg) > Cd (0.16 +/- 0.14 mg/kg) > Hg (0.067 +/- 0.033 mg/kg). These concentrations were all close to the guide values in China and those reported in other studies. However, through the Mann-Kendall test, Cu showed obvious increasing interannual trends, and according to ecological risk assessment, the sediments were highly contaminated with Cu and Hg. The health risks to local residents via oyster intake showed that both noncarcinogenic and carcinogenic risk did not exceed the safety criteria (THQ = 1, TCR = 10(-6)). The current study suggests that ecological and human health risks be integrated to control HMs in the Maowei Estuary.