[Distribution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in the Water of Yuqiao Reservoir Watershed During the Water Delivery Period].

Abstract

In order to understand the pollution status of polycyclic aromatic hydrocarbons (PAHs) in the groundwater of Yuqiao Reservoir Watershed, the 16 US EPA priority control PAHs in the groundwater of this region were analyzed by gas chromatography-mass spectrometry. Not only the distribution characteristics and sources of PAHs, but also the potential probabilistic carcinogenic risk through drinking water and the ecological risk were assessed in this study. The results showed that PAHs could be detected in all the 18 samples. The results showed that the contents and concentration of PAHs were different between the upstream river and Yuqiao Reservoir. For the upstream river, the concentrations of ∑PAHs ranged from 13.7 ng·L-1 to 104.1 ng·L-1, and the low-ring number PAHs was dominant except the site of Sahe river bridge, and 2-3 ring number PAHs accounted for about 86%-95% of the ∑PAHs. The heavier contaminant level was monitored among the intensive fishery breeding areas located in Dahei river reservoir. For the Yuqiao Reservoir, the mass of 2-3 ring and 4-6 ring number PAHs was similar and the concentration of ∑PAHs ranged from 1.6 ng·L-1 to 3512.5 ng·L-1. The highest ∑PAHs was measured at the sampling sites located in the north of reservoir. The resource pollution of PAHs in this region was appointed by the molecular ratio of Flu/Pyr and Fla/(Fla+Pyr) and it showed that the combustion of coal and biomass was predominant during the sampling campaign. The health risk of drinking water in the study area was evaluated using the recommended method by US EPA and the cancer risk exceeded 10-6. The ecological risk was assessed by the value of risk quotient (RQ) adopted by Kalf and the RQs of B[a]A, B[k]F and BaP were all higher than 1. The above results indicated that the government should pay enough attention to the health risk and ecological risk of PAHs in the water of reservoir.