Distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Subei Shoal, China

In this study, 16 polycyclic aromatic hydrocarbons (PAHs) were detected in surface sediments of the Subei Shoal. Eleven of the 16 PAHs were detected, namely, Nap, Fl, Phe, Flu, Pyr, BaAnt, Chr, BaFlu, BaPyr, Ind-1,2,3-cdPyr, and BghiPer, and the remaining five (Acy, Ace, Ant, BkFlu, and DBahAnt) were not detected. Total PAH concentrations ranged from < DL to 25.24 ng/g dw, with an average of 5.88 ng/g dw. The highest concentrations were found in the intermediate sections (stations 6-1), followed by those in the northernmost regions (stations 9-5). The lowest concentrations were found in the south of section 2. High-molecular-weight PAHs (4 and 5 rings) were found to be dominant, constituting 70% of the PAHs tested. Principal component analysis showed that PAHs in sediments came mainly from coal combustion, transportation (oil combustion), coke processing, and petroleum sources. Both effect range low/effect range median values and mean effects range-median quotient showed that PAHs were present at a low toxicity risk level in the Subei Shoal.