Pollution characteristics, risk assessment and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments and water of the Luan River,China
滦河流域多环芳烃的污染特征、风险评价与来源辨析

The distribution of polycyclic aromatic hydrocarbons (PAHs) was studied by determining the levels of 16 PAHs in water and sediment samples of the Luan River, a very important drinking water source for Tianjin and Tangshan, China. A total of 15 water samples and 15 sediment samples were collected during April 2008. The total PAH concentrations in the water varied from 9.8 to 310 ng·L-1, and those in surficial sediments ranged from the detection limit to 478 ng·g-1 dry weight. The results showed that the concentrations of PAHs in rural areas were lower than those near city zones. The estuary areas were less polluted than the middle reaches of the river. The PAHs were dominated by 3-(40.9%) and 4-ring (56.2%) components in water samples and by 3-(30.0%), 4-(39.3%), and 5-ring (15.8%) compounds in sediments. The 3- and 4-ring PAHs were the most common components in the Luan River. The toxic equivalency factors (TEFs) were used to calculate benzoa]pyrene equivalents (EBaP) for water samples. The values in most stations were much lower than the Chinese Environmental Protection Agency (CEPA) guidelines for drinking water,(2.8 ng·L-1) except Hanjiaying (11.8 ng·L-1) and Baohekou (11.4 ng·L-1). Overall, the surface water resources showed some carcinogenic potential. The result of ecological risk assessment indicated that high potential ecological risk of PAHs was not found in sediments of the Luan River, but potential harmful effects on creatures might exist in Hanjiaying, Shangbancheng and Wulongji. The molecular indices and isomer pair ratios were used to infer the sources of PAHs, and the results suggested that anthropogenic heavy fuel combustion was likely to be the main source. Petroleum PAHs also made a major contribution to PAH pollution at Baohekou and Daheiting.