Polluting characteristics, sources, cancer risk, and cellular toxicity of PAHs bound in atmospheric particulates sampled from an economic transformation demonstration area of Dongguan in the Pearl River Delta, China.

ABSTRACT

The Songshan Lake Science and Technology Industrial Park is a national economic transition demonstration area, which centers at a traditional industrial region, in Dongguan, China. We were interested in the involved atmospheric particulates-bound PAHs regarding their sources, cancer risk, and related cellular toxicity for those in other areas under comparable conditions. In this study, the daily concentrations of TSP, PM10, and PM2.5 were averaged 127.95, 95.91, and 67.62 µg/m3, and the bound PAHs were averaged 1.31, 1.22, and 0.77 ng/m3 in summer and 12.72, 20.51 and 40.27 ng/m3 in winter, respectively. The dominant PAHs were those with 5-6 rings, and 4-6 rings in summer and winter, respectively. The incremental lifetime cancer risk (ILCR) (90th percentile probability) of total PAHs was above 1.00E-06 in each age group, particularly high in adolescents. Sensitivity analysis indicated that slope factor and body weight had greater impact than exposure duration and inhalation rate on the ILCR. Moreover, treatment of human bronchial epithelial BEAS-2B cells with mixed five indicative PAHs increased the formation of ROS, DNA damage (elevation in γ-H2AX), and protein levels of CAR, PXR, CYP1A1, 1A2, 1B1, while reduced the AhR protein, with the winter mixture more potent than summer. For the sources of PAHs, the stable carbon isotope ratio analysis and diagnostic ratios consistently pointed to petroleum and fossil fuel combustion as major sources. In conclusion, our findings suggest that particulates-bound PAHs deserve serious concerns for a cancer risk in such environment, and the development of new power sources for reducing fossil fuel combustion is highly encouraged.