Spatial distribution, source analysis, and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the sediments from rivers emptying into Jiaozhou Bay, China.

Sediment samples had been collected from five major rivers into Jiaozhou Bay, China to study the spatial distribution, sources, and ecological risks of 16 priority polycyclic aromatic hydrocarbons (PAHs) in April 2018. Results showed that the contents of PAHs in the sediments from the five rivers were significantly different. The distribution trend was Dagu < Yang < Licun < Baisha < Moshui River. The contents of PAHs in the eastern rivers were higher than those in the western portions. The contribution rate of HMW-PAHs was higher than LMW-PAHs in the sediments, with the majority of PAHs being four rings. PAHs in sediments were mainly derived from combustion sources, including the incomplete combustion of petroleum, coal, and wood. The benzo[a]pyrene toxic equivalent method (TEQ) showed that Moshui River had a high risk of carcinogenesis. The evaluation results of Effects Range Low(ERL), Effects Range Median (ERM) and Mean- Effects Range Median-quotient (M-ERM-Q) showed that PAHs in the sediments of Moshui River would occasionally have adverse biological effects, as well as possible medium and low ecological risks. The ecological risks of PAHs in the sediments of the other four rivers were low. Hence, we should focus on and control the input of PAHs in the Moshui River.