Polycyclic aromatic hydrocarbons in surface sediments of Lingshui County lagoons: distribution, source analysis, and ecological risk assessment

The Lingshui County lagoons represent Hainan's first marine special conservation area, yet little is known about the distribution and source characteristics of PAHs in their surface sediments. This study employed principal component analysis, PMF, and MERM-Q modeling to determine the distribution, sources, and potential ecological risks of PAHs in Lingshui Lagoon's surface sediments. The data indicate: (1) Spring PAH concentrations in the study area ranged from 18.12 to 111.30 ng/g (dry weight), with a mean concentration of 60.83 ng/g. Hexacyclic PAHs accounted for the highest proportion (52.43%), followed by tetracyclic PAHs (21.04%). (2) PMF model analysis revealed that PAHs in the lagoon primarily originate from fossil fuel and biomass combustion. (3) The PAH concentrations in the lagoon's surface sediments indicate moderate to low pollution levels, with relatively minimal potential ecological risk. These findings provide a reference for identifying PAH sources in Lingshui Lagoon's surface sediments and establish a scientific foundation for improving the lagoon's environmental quality.