Pollution characterization and health risk assessment of polycyclic aromatic hydrocarbons in PM_2.5 in an industrial area of Lanzhou

Background Polycyclic aromatic hydrocarbons (PAHs) are important environmental pollutants, some of which are carcinogenic and could increase the carcinogenic health risks among residents living in relevant industrial areas than in other areas.

Objective The purpose of this study is to analyze the pollution characteristics and potential health risks of PAHs in atmospheric fine particulate matters(PM_2.5) of an industrial area in Lanzhou City.

Methods Eighty-four atmospheric PM_2.5 samples were collected from an industrial area in 2017, including 35 samples in heating season and 49 samples in non-heating season. Sixteen PAHs listed as priority pollutants were detected, including naphthalene, acenaphthene, acenaphthylene, fluorene, anthracene, phenanthrene, benzoaanthracene, chrysene, fluoranthene, pyrene, benzoapyrene, benzobfluoranthene, benzokfluoranthene, dibenzoa, hanthracene, benzog, h, iperylene, and indene1, 2, 3-cdpyrene. The equivalent method recommended by US Environmental Protection Agency was used to evaluate the health risk and life expectancy loss from PAHs in atmospheric PM_2.5. The acceptable lifetime carcinogenic risk level was in the range of 1×10^-6-1×10^-4.

Results The annual total concentration of PAHs in atmospheric PM_2.5 in the selected industrial area was (43.51±26.09) ng·m^-3. The total concentration in heating season(60.64±30.88) ng·m^-3 was significantly higher than that in non-heating season(31.27±11.59) ng·m^-3 (Z=-7.252, P < 0.001). In the whole year and the non-heating season, the PAHs were dominated by 2-ring and 3-ring components, accounting for 47.96% and 65.08%, respectively, while in the heating season, the PAHs were dominated by 4-ring components, accounting for 38.41%. The incremental lifetime carcinogenic risk value (V_ILCR) from PAHs in the whole year was 1.24×10^-5. The VILCR in the heating season (2.06×10^-5) was higher than that in the non-heating season (6.50×10^-6), and that in adults (1.46×10^-5) was higher than that in children (1.02×10^-5) (Z=-7.223, -2.573, P < 0.05). The life expectancy loss of PAHs was 90.59 min.

Conclusion The lifetime carcinogenic risk of atmospheric PAHs in Lanzhou industrial zone in the heating season is higher than that in the non-heating season, and that in adults is higher than that in children, but they are within the preset acceptable range.