Multi-indicator assessment of heavy metal pollution in Qinzhou Harbour sediments: Unraveling ecological and human health risks

The study of heavy metal content in the sediments of the coastal zone of Qinzhou Harbour was used to analyse the level, distribution and sources of heavy metal pollution in the region and its hazards to the ecological environment and human health. The results showed that the average concentrations of Mn, Ni, Cr, Cu, and Pb exceeded background values along the shores of Qinzhou Harbour, Guangxi. Comprehensive assessments using Igeo, RI, and PLI identified Cu, Ni, and Pb as primary contaminants in the area, presenting slight to moderate ecological risks and biological toxic effects. Source analysis suggested that these metals primarily originated from anthropogenic activities including shipbuilding, chemical plant discharges, oil refining, and industrial smelting. Integrating SQGs with human health risk models revealed carcinogenic risks associated with Ni exposure, particularly for children. However, noncarcinogenic risks were not significant, and the risk to children was higher than to adults.