Assessment of the human health risk of polycyclic aromatic hydrocarbons in soils from areas of crude oil exploitation

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous carcinogenic pollutants. Areas where crude oil has been exploited are at risk due to PAHs from both natural and anthropogenic sources. The Shengli Oilfield in China was used to assess the health risk posed by PAHs in areas with different population densities. A risk assessment showed that in the areas with low, median, and high population densities, the probabilities of the total carcinogenic risk (TCR) exceeding 10−6 for adults were 9.9%, 9.3%, and 13.4%, respectively, whereas these were 7.8%, 7.1%, and 10.1%, respectively, for children. Crude oil, traffic, and residential emissions were the major sources of PAHs based on a factor analysis with a nonnegative constraint analysis. Crude oil sources accounted for 96.1% of the TCR in the low population area, whereas traffic accounted for 94.4% of the TCR in the high population area. Based on the national action plan, guidelines, and new standard for soil pollution control promulgated by the Chinese government, we assumed a reduced rate of soil PAHs from different sources, and the carcinogenic risk from PAHs in the area of crude oil exploitation could be forecast. The average probabilities of the TCR exceeding 10−6 for adults and children could be reduced by 45.8% and 49.4%, respectively, in 2040 relative to current values under a pollution control scenario. These findings highlight that the risks associated with soil contamination could be effectively controlled by implementing control policies.