Distribution, Multi-Index Assessment, and Sources of Heavy Metals in Surface Sediments of Zhelin Bay, a Typical Mariculture Area in Southern China

The occurrence, multi-index assessment, and sources of heavy metals in surface sediments of Zhelin Bay were investigated. Average heavy metal concentrations (mg/kg) were 81.89 (Cr), 770.76 (Mn), 16.81 (Co), 62.25 (Ni), 96.30 (Cu), 162.04 (Zn), and 73.40 (Pb), with the concentrations of studied seven heavy metals being significantly higher than their corresponding background values. Geo-accumulation index (I-geo) and pollution load index (PLI) were implemented to assess degree of heavy metal contamination. The I-geo and PLI indicated that Cr, Mn, Co, Zn, and Pb were slightly polluted, and Cu and Ni were moderately polluted in the region. Potential ecological risk index (RI) and mean possible effect level (PEL) quotient were conducted to assess ecological risk. The RI and mean PEL quotient demonstrated that surface sediments of Zhelin Bay were slight ecological risks and exhibited a 21% probability of toxicity. Principal component analysis (PCA) combined with the correlation analysis (CA) and hierarchical cluster analysis (HAC) revealed that the heavy metal contamination in Zhelin Bay might originate from three type sources.

Automated summary

This study investigated the occurrence, multi-index assessment, and sources of heavy metals in surface sediments of Zhelin Bay. The concentrations of seven heavy metals were found to be significantly higher than their corresponding background values. The assessment using geo-accumulation index (I-geo) and pollution load index (PLI) indicated that some heavy metals were slightly polluted or moderately polluted in the region. The ecological risk assessment using potential ecological risk index (RI) and mean possible effect level (PEL) quotient showed that the surface sediments of Zhelin Bay had slight ecological risks and a 21% probability of toxicity. Principal component analysis (PCA) combined with correlation analysis (CA) and hierarchical cluster analysis (HAC) revealed three potential sources of heavy metal contamination in Zhelin Bay.