Polycyclic aromatic hydrocarbons (PAHs) pollution and risk assessment of soils at contaminated sites in China over the past two decades

Abstract

With rapid urbanization in China, soil pollution at contaminated sites has emerged as a significant concern in the environmental protection plan. Moreover, extensive research has focused on the analysis of other major contaminants. However, over the past two decades, only a few studies have systematically analyzed polycyclic aromatic hydrocarbons (PAHs) in contaminated soils, particularly their source identification, contamination level assessment, and risk evaluation. This study addressed these research gaps by comprehensively evaluating soil PAHs contamination at these sites through the collection and screening of relevant literature data from the past 20 years using a “front page filtering” approach. The results suggested that the most contaminated sites in China were associated with petrochemical plants, steel mills, and coking plants. Coal/biomass burning emerged as the predominant source of PAHs pollution in the soils of contaminated sites across China. Overall, the soils of contaminated sites exhibited relatively low levels of PAHs contamination. The single-factor index method showed that benzo(a)pyrene (BaP) was the PAH monomer with the highest contamination level. Geographically, Northeast and North China exhibited relatively higher contamination levels and ecological risks. Moreover, PAHs posed significant health hazards, as they exhibited significantly high toxic effects on the respiratory system, carcinogenicity, aromatic hydrocarbon receptors, estrogen receptors, and antioxidant response elements. Additionally, children and youths faced higher health risks than adults. The findings from this study provide a solid basis for developing strategies to manage PAHs at contaminated sites in China.