Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Environ Int. 2017 Nov;108:261-270. doi: 10.1016/j.envint.2017.09.001. Epub 2017 Sep 11.
The quality of agricultural soil is vital to human health, however soil contamination is a severe problem in China. Polycyclic aromatic hydrocarbons (PAHs) have been found to be among the major soil contaminants in China. PAH derivatives could be more toxic but their measurements in soils are extremely limited. This study reports levels, spatial distributions and compositions of 11 nitrated (nPAHs) and 4 oxygenated PAHs (oPAHs) in agricultural soils covering 26 provinces in eastern China to fill the data gap. The excess lifetime cancer risk (ELCR) from the exposure to them in addition to 21 parent PAHs (pPAHs) via soil ingestion has been estimated. The mean concentration of ∑nPAHs and ∑oPAHs in agricultural soils is 50±45μg/kg and 9±8μg/kg respectively. Both ∑nPAHs and ∑oPAHs follow a similar spatial distribution pattern with elevated concentrations found in Liaoning, Shanxi, Henan and Guizhou. However if taking account of pPAHs, the high ELCR by soil ingestion is estimated for Shanxi, Zhejiang, Liaoning, Jiangsu and Hubei. The maximum ELCR is estimated at ca.10 by both deterministic and probabilistic studies with moderate toxic equivalent factors (TEFs). If maximum TEFs available are applied, there is a 0.2% probability that the ELCR will exceed 10 in the areas covered. There is a great chance to underestimate the ELCR via soil ingestion for some regions if only the 16 priority PAHs in agricultural soils are considered. The early life exposure and burden are considered extremely important to ELCR. Emission sources are qualitatively predicted and for areas with higher ELCR such as Shanxi and Liaoning, new loadings of PAHs and derivatives are identified. This is the first large scale study on nPAHs and oPAHs contamination levels in agricultural soils in China. The risk assessment based on this underpins the policy making and is valuable for both scientists and policy makers.
农业土壤的质量对人类健康至关重要，但土壤污染在中国是一个严重的问题。多环芳烃（PAHs）已被发现是中国主要的土壤污染物之一。PAH 衍生物可能更具毒性，但它们在土壤中的测量极为有限。本研究报告了中国东部 26 个省份农业土壤中 11 种硝化（nPAHs）和 4 种含氧 PAHs（oPAHs）的水平、空间分布和组成，以填补数据空白。此外，还通过土壤摄入估算了它们与 21 种母体 PAHs（pPAHs）共同暴露对人体产生的额外终生癌症风险（ELCR）。农业土壤中∑nPAHs 和∑oPAHs 的平均浓度分别为 50±45μg/kg 和 9±8μg/kg。∑nPAHs 和∑oPAHs 均呈现出相似的空间分布模式，辽宁、山西、河南和贵州的浓度较高。然而，如果考虑到 pPAHs，通过土壤摄入估算出山西、浙江、辽宁、江苏和湖北的高 ELCR。确定性和概率研究均使用中等毒性等效因子（TEFs）估算出的最大 ELCR 约为 10。如果应用可用的最大 TEFs，则在所覆盖的区域中，ELCR 超过 10 的概率为 0.2%。如果仅考虑农业土壤中的 16 种优先 PAHs，则一些地区通过土壤摄入估算的 ELCR 很有可能被低估。早期生活暴露和负担被认为对 ELCR 极为重要。对排放源进行了定性预测，对于山西和辽宁等高 ELCR 地区，确定了 PAHs 和衍生物的新负荷。这是中国首次对农业土壤中 nPAHs 和 oPAHs 污染水平进行的大规模研究。基于此的风险评估为政策制定提供了依据，对科学家和政策制定者都具有重要价值。
