合山煤矸石堆周边土壤中多环芳烃的空间分布特征

Spatial Distribution of PAHs in Soils Around Coal Gangue Piles in Heshan

选取广西合山的-座煤矸石堆,研究其周边土壤中多环芳烃（PAHs）的空间分布特征.沿西南、东北、东南3 个方向,采集距煤矸石堆不同距离不同深度的土壤样品.结果表明：在该研究区域内16 种优先控制PAHs 均有检出,5～15、45～55 和85～95 cm 深度土壤PAHs 总含量范围分别为1 152. 0～11 146. 4、241. 8～4 867. 7 和116. 4～2 666. 0 μg·kg^-1,存在严重的生态风险;平面上,随距矸石堆距离由近及远,土壤中PAHs 含量由大到小变化,垂向上,由浅到深,PAHs 含量也呈递减变化,且沿程与垂向上的变化趋势都是先急后缓;土壤中PAHs 含量的平面分布主要受控于风向和坡度,垂向分布受控于PAHs 本身的水溶性和土壤性质;通过相关分析认为Nap、Phe、Fle、Bbf、Chr 和Fla 这6 种化合物是研究区煤矸石堆周边土壤中PAHs 的特征化合物类型,重环PAHs 相较于轻环PAHs 受除煤矸石堆以外的其他污染源的影响较小.

Soil samples were collected from different soil layers at sampling sites different in distance from the coal gangue pile and different in direction to the pile,southwest,northeast and southeast for analysis of content and spatial distribution of PAHs. Results show that all the 16 priority-controlled PAHs were detected in the soil samples. The total PAHs in the 5- 15,45- 55 and 85- 95 cm soil layers varied in the range of 1 152. 0- 11 146. 4,241. 8- 4 867. 7 and 116. 4-2 666. 0 μg·kg- 1,respectively,posing a serious ecological risk. Horizontally,PAHs content in the soil decreased with the increasing distance of the sampling site from the gangue pile and vertically with the increasing soil depth as well. The changes along both directions started drastically and gradually slowed down. Horizontal distribution of PAHs in the soil was controlled by wind direction and gradient of slope,while vertical distribution in the soil by water solubility of PAHs and soil properties. Correlation analysis indicates that Nap,Phe,Fle,Bbf,Chr and Fla were the typical PAHs detected in the surrounding soils of the pile,and heavy ring PAHs were less affected by other pollution sources than light ring PAHs.