快速城市化地区土壤多环芳烃的空间分布及来源:以深圳市为例

Spatial Distribution,Sources and Risk Assessment of Polycyclic Aromatic Hydrocarbons in a Rapid Urbanization City: Shenzhen

城市化的生态环境效应已成为当前全球环境变化研究的热点问题。以快速城市化地区深圳市为例,利用不同功能区的土壤调查数据,研究深圳市城市土壤多环芳烃(PAHs)含量、组分与来源的空间分布特征,并评估城市土壤PAHs的环境与健康风险。结果表明:深圳市主城区表层土壤中16种PAHs总含量为73. 47～2 309. 88ng·g^(-1),平均值为494. 34 ng·g^(-1); 7种致癌PAHs总含量为24. 45～1 274. 96 ng·g^(-1),平均值为257. 35 ng·g^(-1),占总量的52. 1%。在空间分布上以工业密集区表层土壤PAHs含量为最高,其次是人口和交通密集区,绿地比例大的区域最低。正定矩阵因子分解法(PMF)模型分析结果表明煤、石油等高温燃烧与交通废气排放是深圳市主城区表层土壤PAHs的最主要来源。深圳市主城区表层土壤PAHs平均含量对儿童和成人的致癌风险平均值均小于10^(-6),表明深圳市土壤环境质量总体优良,但局部样点对儿童和成人致癌风险的最大值达到10^(-6),存在潜在的致癌风险。快速城市化地区城市土壤污染防控应该引起重视,以保障城市经济与生态环境的协调发展。

Urbanization and its environmental impact are important topics in global environmental change.In this study,93 urban soil samples from different land-use types in Shenzhen,China,were used to investigate the spatial and temporal analysis of PAHs content,components and sources in Shenzhen urban green space.High spatial resolution mapping was conducted to assess the environmental and health risks of PAHs in urban green spaces.The results show that the total PAHs contents in the surface soil of the main Shenzhen urban area were between 73.47-2 309.88 ng·g^-1,with an average of 494.34 ng·g^-1.The total content of seven carcinogenic PAHs was between 24.45 and 1 274.96 ng·g^-1,with an average of 257.35 ng·g^-1,accounting for 52.1% of the total PAHs.In the spatial distribution,the PAHs content was highest in industrially dense areas,followed by population and traffic-intensive areas,and the PAHs content was lowest in areas with a large proportion of green spaces.The PMF model show that coal-fired high-temperature combustion and traffic exhaust emissions were the main sources of surface PAHs in the main urban areas of Shenzhen.ILCRs and CR in different exposure approaches was less than 10^-6 for both children and adults,indicating that the soil environmental quality in Shenzhen was generally good,but the maximum carcinogenic risk for children and adults reached 10^-6 in some locations,which indicates potential health risks.The prevention and control of urban soil pollution needs to be taken seriously to ensure the coordinated development of urban economy and ecological environment.