Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediment from the upper reach of Huaihe River, East China

To assess the status of polycyclic aromatic hydrocarbons (PAHs) contamination in sediments from the upper reach of Huaihe River, East China, 16 surface sediment samples were collected in March 2007 and analyzed for 16 USEPA priority PAHs. The results indicated that the total concentrations of 16 PAHs (aPAHs) were 95.2-877.5 mu g kg(-1) dry weight (dw) with a mean value of 370.8 mu g kg(-1) dw for the main stream, 85.7-935.2 mu g kg(-1) dw with a mean concentration of 480.7 mu g kg(-1) dw for tributaries, and 144.8-303.2 mu g kg(-1) dw with an average concentration of 224.0 mu g kg(-1) dw for lakes. PAHs pollution was closely related to sewage input and industrial activities. Furthermore, the distribution of PAHs in sediments from the main stream indicated that the input of tributaries was an important factor for Huaihe River. In comparison to a worldwide survey of sedimentary PAHs concentrations, PAHs pollution in Huaihe River sediments was ranked as low to moderate. The dominant compounds in surface sediment samples were four-ring and five-ring PAH compounds. Selected PAH ratios suggested that PAHs mainly came from the contamination of pyrogenic processes, such as coal and biomass combustion. Risk assessment indicated that PAHs in sedimentary environment in the upper reach of Huaihe River may cause mild toxic effects but would not cause immediate biological effects.