[Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons and Their Derivatives in Wastewater-Receiving Rivers in Beijing].

To analyze the pollution levels and health risk assessment of Polycyclic Aromatic Hydrocarbons (PAHs) and their derivatives (SPAHs) in five typical effluents from sewage treatment plants and receiving rivers in Beijing, the concentrations of PAHs and SPAHs in samples were measured by the combined method of solid extraction and gas chromatography-mass spectrometry. The distribution characteristics were also analyzed. At the same time, the probabilistic health risk was assessed using toxic equivalent factors. The results show that the contamination of PAHs and SPAHs in five typical effluents from sewage treatment plants and receiving rivers in Beijing is 75-584 ng·L and 91-1822 ng·L, respectively. These PAHs are dominated by 2-and 3-ring PAHs, which account for 23%-48% of the total PAHs. The SPAHs in this study include three substances:methyl polycyclic aromatic hydrocarbons (MPAHs), oxygenated polycyclic aromatic hydrocarbons (OPAHs), and chlorinated polycyclic aromatic hydrocarbons (ClPAHs). The proportion of OPAHs in total SPAHs is 75%, while the total proportion of MPAHs and ClPAHs is overall low (12% and 13%, respectively). Calculations of the toxicity equivalents of PAHs in five rivers indicate that attention should be paid to high-PAHs pollution during the heating season (December).