Pollution characteristics and risk assessment of polycyclic aromatic hydrocarbons in the sediment of Wei River

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants which can be accumulated in river sediment, posing potential threats to ecosystem and human health. A total of 20 surface sediment samples were collected in Wei River, and 16 priority PAHs were analyzed for pollution features as well as ecological and human health risk. The results showed that the sum of the 16 PAHs (Σ16PAHs) in the sediment of Wei River ranged from 60.5 to 10,241.1 ng g−1 dw, with an average of 2250.4 ng g−1 dw. The total of seven carcinogenic PAHs (ΣCPAHs) was in the range of 5.8–7232.7 ng g−1 dw, with a mean of 1276.5 ng g−1 dw, accounting for 56.7% of the Σ16PAHs and presenting a high carcinogenic potential. Elevated Σ16PAHs and ΣCPAHs were observed in the lower reach of Wei River. PAHs in the sediment were dominated by 3- and 5-ring PAHs, and mainly related to various combustion processes. The ecological risk of individual PAHs (except for Chy) in the sediment was not to be neglected, with the highest risk of Acy and Flu. The total ecological risk of PAHs in the sediment was a moderate to high level. The non-carcinogenic risk of exposure to PAHs for children, adolescences and adults was insignificant. The carcinogenic risk of exposure to PAHs was in the range of 10–6—10–4 for children, adolescences and adults, indicating an acceptable carcinogenic risk.