Pollution characteristics and population health risks of polycyclic aromatic hydrocarbons (PAHs) in coking contaminated soils

Abstract

Coking is considered as a significant source of PAHs emission in China. In order to investigate pollution characteristics of PAHs in soils affected by coking industry and associated health risk, a total of 46 soil samples were collected from a typical coking industrial zone located in Shanxi province of China. The total concentration of the 16 PAHs (Σ16PAHs) ranged from 400 to 5.52 × 104 μg·kg−1, with an average of 3.56 × 103 μg·kg−1. Seven carcinogenic PAHs (∑7cPAH) accounted for approximately 48% of the total concentration. Compared to other coking areas, the content of PAHs in the study area was relatively high. By exploring the correlativity between Σ16PAHs and benzo(a)pyrene equivalent (BaPeq) concentrations, a regression equation for estimating total PAHs concentration from BaP measurement was established. PAHs in coking soils were found to be dominated by low molecular weight PAHs with 2∼3 rings. According to the results of diagnostic ratios, Fla/(Fla+Pyr), BaA/(BaA+Chr) and IcdP/(IcdP+BghiP) ratios could well indicate coking source of PAHs in the soil. The incremental lifetime cancer risk (ILCR) analysis indicated that the carcinogenic effects on the local residents were far beyond priority risk level (10−5). To effectively manage the coking zone, ILCR model combined with population density was conducted. From the risk distribution of population carcinogenic risk (PCR), 6.64% of the area was under high risk and 38.67% was under potential risk. These two kinds of region were the focus for risk control. The results of this study provide useful information for local authorities to take effective measures to ensure human health.