Liu Hui, Li YanXi, He Xi, Sissou Zakari, Tong Lei, Yarnes Chris, Huang Xianyu
State Key Laboratory of Biogeology and Environmental Geology and School of Environmental Studies, China University of Geosciences, Wuhan 430074, PR China.
State Key Laboratory of Biogeology and Environmental Geology and School of Environmental Studies, China University of Geosciences, Wuhan 430074, PR China.
Chemosphere. 2016 Feb;144:1831-6. doi: 10.1016/j.chemosphere.2015.10.080. Epub 2015 Nov 11.
The present paper aims to evaluate the carbon isotopic fractionation of phthalate esters (PAEs) during transport in an sandy aquifer. Breakthrough curves of di-methyl phthalate (DMP), di-ethyl phthalate (DEP), and di-n-butyl phthalate (DBP) in mixed solution were determined by miscible displacement experiment, and simulated using HYDRUS-1D software. The stable carbon isotopes (δ(13)C) of 3 PAEs in effluent were analyzed at different times. Results showed that, in the transport process in sandy sediment, PAEs are mainly trapped into the pore space instead of being adsorbed on the surface of particles. At the initial stage of transport, PAEs with lighter carbon tend to run faster in the sandy sediment, and PAEs with heavier carbon run after. However, there is no priority for the transport of PAEs with different carbon isotopes at Stage Ⅱ with mainly time-limited sorption. So the transport-based isotope fractionation occurs in the front area of contaminant plume. This effect may be relevant for interpreting carbon isotope signatures in the real contaminant site.
本文旨在评估邻苯二甲酸酯（PAEs）在砂质含水层中运移过程中的碳同位素分馏情况。通过混溶置换实验测定了邻苯二甲酸二甲酯（DMP）、邻苯二甲酸二乙酯（DEP）和邻苯二甲酸二正丁酯（DBP）混合溶液的穿透曲线，并使用HYDRUS-1D软件进行模拟。在不同时间分析了流出物中3种PAEs的稳定碳同位素（δ(13)C）。结果表明，在砂质沉积物的运移过程中，PAEs主要被困在孔隙空间中，而不是吸附在颗粒表面。在运移初期，碳含量较轻的PAEs在砂质沉积物中跑得更快，碳含量较重的PAEs随后运移。然而，在主要为限时吸附的Ⅱ阶段，不同碳同位素的PAEs运移没有优先顺序。因此，基于运移的同位素分馏发生在污染羽的前端区域。这种效应可能与解释实际污染场地中的碳同位素特征有关。
