Ecological risk assessment of heavy metal pollution in the water of China's coastal shellfish culture areas.

In order to learn about the status of heavy metals and ecological risks in the water of thirteen China's costal shellfish culture areas, principal component analysis was applied to analyze the distributions of five kinds of heavy metal, while the safety threshold method was employed to evaluate the ecological risks. The results showed that among the 13 shellfish culture areas, the average metal concentrations were in the order of Zn > Cu > Pb > Hg > Cd, and all heavy metals were below the second standards for sea water quality of China. The distribution of heavy metals in 13 shellfish culture areas was reflected by two principal components with the contribution rates of F1(Cu) and F2(Zn, Pb) were 36.14% and 23.40%,respectively,which was less affected by economic and geographical differences. The ecological risks assessment of five kinds of heavy metals showed that MOS10 was more than one; the probabilities of five heavy metals affecting more than 10% of aquatic organisms were 49.52%, 24.11%, 17.49%, 22.05%, and 5.66%, respectively, the ecological risk of five main heavy metals was in order Cu > Zn > Cd > Pb > Hg. In the selected thirteen shellfish culture areas, the value of msPAF of seven culture areas was higher than 20%, indicating these areas are highly ecologically contaminated by heavy metals, and the other four shellfish culture areas with value of 0, indicating that these areas have no ecological risk of heavy metals pollution.