• 关键词：多环芳烃  淋滤  土柱  迁移

• 基金项目：国家自然科学基金资助(No.40473045)

• 何奉朋
• 1. 长庆油田公司第一采油厂地质所, 延安 716000; 2. 中国石油大学油气资源与探测国家重点实验室, 北京 102249

• 张枝焕
• 中国石油大学油气资源与探测国家重点实验室, 北京 102249

• 汪淑洁
• 中国石油大学油气资源与探测国家重点实验室, 北京 102249

• 摘要：京津地区典型土壤剖面分析表明,土壤中PAHs含量和组成均随深度增大而呈现明显的变化.为了揭示PAHs在土壤剖面中的迁移特征与控制因素,开展了室内土柱模拟实验,考察了PAHs的迁移特点及影响因素,特别是土壤有机质含量的影响.采用3种土壤质地和TOC不同的土样装填土柱,以去离子水作为淋滤液对预先加入土柱表层的污染物(包括不同环数PAHs、d-Flu)进行淋滤,当达到淋滤量后分析土柱中PAHs含量及组成.结果表明,不同实验条件下,淋滤后土壤剖面不同层次土壤中PAHs含量均高于原土样中的,且PAHs主要富集在土柱表层,随深度增加其含量明显降低,但不同土柱中降幅不同;不同环数PAHs分布特征存在差异,与原土柱相比,除d-Flu和Flu等低环数芳烃的含量在剖面不同深度均有明显增大外,部分高环数PAHs相对含量在土柱的不同深度也明显增加,说明高环数PAHs也具有一定的迁移能力,但相对于3环PAHs,高环数PAHs在土壤中迁移能力较低.此外,土壤剖面PAHs的富集程度明显受土壤中TOC影响,PAHs总量或单体PAH含量在土柱中迁移的深度随着TOC含量降低而增加.

• Abstract：Analyses have shown that the concentrations and the compositions of polycyclic aromatic hydrocarbons(PAHs)in the representative soil profiles of Beijing and Tianjin change obviously with depth.In order to reveal the migration behavior and critical factors affecting PAHconcentrations in soil profiles,laboratory simulations of soil columns were designed to determine the factors,especially soil organic matter content,which affect migration behavior of PAHs.Three soil matrices with different textures and TOC,pre-saturated with deionized water,were loaded into columns.Pollutants(including PAHs and d₁₀-flu)were added to the surface soil and then the columns were leached with deionized water.The results indicate that the concentration distribution of PAHs in each column showed similar trends with depth:mainly accumulating at the surface,and decreasing sharply with depth,but depending on the various compounds in the different columns.The concentrations were still higher than those of the original soil samples.Compared to the original soil profiles,the distributions of the PAHs with different rings along the soil column profile were different:the relative contents of d₁₀-fluorene and fluorine etc.,increased obviously over those of the originals.The concentrations of the multiring PAHs also increased obviously and migrated somewhat,but had a weaker migration compared to low molecular weight PAHs(<3 rings).Moreover,the migration depth of PAHs or any individual PAHchanged obviously with different TOC:both increased more at lower TOCconcentrations,which indicates the effect of soil organic matter on the migration of the target compounds.

• Key words：PAHs  leaching  soil columns  migration

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