A total of 13 surface sediment samples were collected from estuaries of the Maoling, Dalan, and Qinjiang rivers for heavy metal analysis, aiming to study the distribution characteristics and ecological risk of heavy metals in the surface sediments of the Maowei Sea estuary. The results are as follows. The average contents of heavy metals As, Cd, Cr, Cu, Hg, Pb, and Zn in Maowei Sea sediments were 7.78×10-6, 0.14×10-6, 37.6×10-6, 18.9×10-6, 0.0048×10-6, 22.5×10-6, and 54.7×10-6, respectively. They are all lower than the class-I standard specified in GB18668—2002. The heavy metals in the sediments show quite different spatial distribution, with high content of heavy metals concentrating in the industrial zone to the east of the Maowei Sea and near the Maoling River to the west of the Maowei Sea. The analysis of heavy metal pollution shows that most elements are at levels of no pollution to moderate pollution, and Cr is at a medium pollution level. As indicated by the ecological risk analysis, the heavy metals generally show potentially low potential risks, and Hg and Cd in the industrial zone to the east show moderate ecological risks. The sources of heavy metal pollutants were explored through correlation analysis, cluster analysis, and principal component analysis. The results show that heavy metal pollution is mainly controlled by rivers, and Hg, As and Cd are also affected by wastewater discharged from the port industrial zone. This comprehensive study shows that the Maowei Sea has a good ecological environment overall, but it is recommended to focus on the drainage of heavy metal pollution in the industrial zone to the west of the Maowei Sea.
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