我国农业土壤及农作物中多环芳烃污染特征与来源

Characteristics and sources of polycyclic aromatic hydrocarbons contaminations in agricultural soils and crops in China

为准确评估我国农田区域环境状况,以多环芳烃(PAHs)为研究对象,收集并整理近十年的农业土壤及农作物PAHs污染调查结果,基于此,系统分析我国农业土壤及农作物中PAHs的含量、组成、分布特征及来源。结果表明:我国大部分农业土壤PAHs污染为中低污染水平,残留值为0~40300.0μg/kg,中位值为499.2μg/kg,平均值为993.0μg/kg。西北地区农业土壤PAHs含量平均值最高,最高可达3836.5μg/kg。农业土壤PAHs残留以高分子量多环芳烃为主,占比达58.74%,主要来自化石燃料、煤的不完全燃烧。农作物中PAHs的残留值为23.4~1001.3μg/kg,中位值为173.8μg/kg,平均值为223.9μg/kg。西北地区农作物中PAHs平均残留量高于其他区域。低分子量PAHs在农作物PAHs残留中所占比例较大,达60.55%。本研究为我国农业土壤及农作物中PAHs防治提供参考依据。

To accurately access the environmental conditions of farmland in China,polycyclic aromatic hydrocarbons(PAHs)were selected as the representatives for organic pollutants.Literatures on PAHs in agricultural soils and crops published in the past 10 years were collected and accessed.Based on these,the characteristics of PAH contamination(including residues,composition and distribution)and sources were analyzed systematically.The results showed that most of agricultural soils were polluted by PAHs at low-medium level in China,ranging from 0 to 40300.0μg/kg(median:499.2μg/kg,mean:993.0μg/kg).The average content of PAHs in agricultural soils was 3836.5μg/kg in soils of Northwestern China,which was higher than that in other areas.High-molecular-weight PAHs(accounting for 58.74%)were the main components of PAHs in agricultural soils,which mainly came from the incomplete combustion of fossil fuels and coal.The residues of PAHs in crops ranged from 23.4 to 1001.3μg/kg(median:173.8μg/kg,mean:223.9μg/kg).Similarly,the average residues of PAHs in crops in Northwestern China higher than those in other areas.Low-molecular-weight PAHs were main ingredients of PAH residues in crops,accounting for 60.55%.Our findings could provide a reference for the prevention and control of PAHs in agricultural soils and crops in China.