Release of phthalate esters from a local landfill in the Tibetan Plateau: Importance of soil particle-size specific association.
Release of phthalate esters from a local landfill in the Tibetan Plateau: Importance of soil particle-size specific association.
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DOI：
10.1016/j.scitotenv.2021.151281
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Qi Wang;Kai Lv;An-Ting Wang;Xiaojun Liu;Ge Yin;Jie Wang;Xinyu Du;Jun Li;G. Yuan
中科院分区：
文献类型：
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作者：
Qi Wang;Kai Lv;An-Ting Wang;Xiaojun Liu;Ge Yin;Jie Wang;Xinyu Du;Jun Li;G. Yuan
背景区邻苯二甲酸酯(PAE)的高负荷可直接归因于局部来源，其与土壤颗粒的相关性可能决定环境行为。然而，关于PAEs在土壤中从点源到环境的特定粒度分布还知之甚少。在本研究中，从拉萨垃圾填埋场周围的表层土壤和土壤剖面(0-200μcm)中，测定了粘土(<；2μm)、粉土(2-63μm)和砂粒(63-250μm)中的12种PAE同系物。土壤中多环芳烃的总浓度在0.44~22.3g/g之间，以邻苯二甲酸二乙基己酯(μ)为主。随着距离填埋场距离的增加，粘粒吸附PAEs呈下降趋势。这种分布模式符合高斯空气污染模型，说明粘土吸附的PAEs在空气中的迁移方式是气态的。Boltzmann方程解释了泥沙吸附PAEs的空间变化，反映了泥沙吸附PAEs在大气中的弥散。相比之下，周围土壤中吸附沙粒的PAEs表现为下坡积累，这可能是由于沙粒的风沙运移所致。根据观测浓度和III级逸度模型模拟的土壤清单，推测了最丰富的PAE同系物DEHP的半衰期，结果表明，DEHP在深层土壤中的半衰期(约24000小时)明显长于表层土壤(5500小时)。研究表明，土壤中PAE的分布和去向取决于它们与源区颗粒物的相互作用，而DEHP在深层土壤中的相对稳定性将进一步增加土壤中PAE的存量。
High loads of phthalate esters (PAEs) in background regions can be directly attributed to the local sources, and their association with soil particles may determine the environment behaviors. However, little is known about the particle-size specific distributions of PAEs in soils from point source to the surroundings. In this study, 12 PAE congeners were measured in clay (< 2 μm), silt (2–63 μm) and sand fractions (63–250 μm) from surficial soils and soil profiles (0–200 cm) around the Lhasa landfill. The total concentrations of PAEs in bulk soils varied from 0.44 to 22.3 μg/g, with a dominance of bis(2-ethylhexyl) phthalate (DEHP). The clay-sorbed PAEs exhibited a decreasing trend with the increasing distance from landfill. This distribution pattern was well described by the Gaussian air pollution model, suggesting the airborne particles/gaseous transport of clay-sorbed PAEs. The Boltzmann equation explained the spatial variation of silt-sorbed PAEs, reflecting the atmospheric dispersion of silt-sorbed PAEs. In comparison, the sand-sorbed PAEs in surrounding soils showed downslope accumulation possibly due to the aeolian transport of sand particles. Half-life of the most abundant PAE congener DEHP was assumed based on the soil inventories from observed concentration and the Level III fugacity model simulations, and the results indicated significant longer half-life of DEHP in deeper soils (~24,000 h) than in surficial soils (5500 h). This study elucidates that the distribution and fate of soil PAEs would depend on their association with particles in the source area, and the relative stability of DEHP in deeper soils would further increase PAE inventory in soil compartment.