This paper is the result of coastal geological survey engineering.

Objective This study aims to evaluate the ecological risk posed by polycyclic aromatic hydrocarbons in the Caofeidian sea area, and provide essential data to support environmental protection efforts.

Methods The study involved the determination and analysis of the concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments. Additionally, an ecological risk assessment of PAHs in the study area was conducted using the mass reference method and mean effect interval median quotient (MERM-Q) method.

Results The total concentration of PAHs (∑PAHs) in surface sediments in the entire study area ranged from non-detectable (ND) to 144 ng/g, with an average concentration of 45.81 ng/g. Four-ring and five-ring PAHs were identified as the predominant compounds, accounting for 61% of the total PAH contents. The PAHs were mainly derived from the petroleum combustion, with a significant contribution from gasoline, diesel, and motor vehicle exhaust emissions. Additionally, PAHs were also traced back to coal and biomass burning sources, with a minor fraction originating from petroleum sources.

Conclusions The ecological risk posed by polycyclic aromatic hydrocarbons (PAHs) in the study area is minimal. However, the presence of monomer PAHs (BbF, BkF, InP, BghiP) without a minimum risk value suggests the possibility of ecological harm, necessitating ongoing attention.