Distribution and risk assessment of polycyclic aromatic hydrocarbons in the surface sediments of Daliao River Estuary and its adjacent regions,China

Polycyclic aromatic hydrocarbons (PAHs) pollution concentrations in surface sediments from Daliao River estuary and its adjacent areas (including upstream river and coastal sea areas) was detected by GC-MS,and their sources and ecological risks were assessed.The results showed that the total concentration of PAHs (PAHs) in sediment ranged from 36510-9 to 1158910-9 g/g dry weight (dw) with a mean value of 370010-9 g/g dw.Comparing with the previous reports,the pollution level increased.PAHs concentrations had no clear distribution regularity in various stations from upstream rivers to the coastal sea areas.These characteristics might be caused by the sedimentation properties of suspended particulate matters and the re-distribution of surface sediment with PAH pollution under the action of salt tide.PAHs composition analysis and characteristics ratios were used to analyze the sources of PAHs in surface sediments.The results suggested that PAHs in surface sediments were mainly generated from pollution of petroleum,and followed by the incomplete combustion of coal and other biomass fuels.The results of risk assessments indicated that the probability of harmful biological effects caused by PAH pollution was higher in the studied regions,and relevant management department should pay more attention to this situation.