Solvent release into a sandy aquifer. 1. Overview of source distribution and dissolution behavior
Solvent release into a sandy aquifer. 1. Overview of source distribution and dissolution behavior
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DOI：
10.1021/es980097d
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发表时间：
1999-03-01
影响因子：
11.4
通讯作者：
Cherry, JA
中科院分区：
文献类型：
--
作者：
Broholm, K;Feenstra, S;Cherry, JA
本文介绍了在加拿大安大略博登的加拿大部队基地进行的一次野外试验的一些结果。将5升氯化溶剂混合物（2.0 L三氯乙烯、0.5 L氯仿和2.5 L四氯乙烯）释放到桑迪含水层中，以产生非均匀分布的源。从这个源的溶解和溶解相羽发展详细研究沿着一个横截面下降梯度的源约1年的时间。在实验结束时，对现场进行挖掘，以绘制地下溶剂残留物的实际分布图。溶解相的浓度超过10%的有效溶解度的个别组件的部分羽直接downgradient的源，提供了一个强有力的指示致密的非水相液体（DNAPLs）的存在。溶解相浓度在几个采样点超过50%的有效溶解度。然而，即使进行了详细的地下水监测，也无法确定DNAPL源的小规模分布。较低的溶解浓度发生在比DNAPL源区更深的地方，这可能是由于地下水位高程波动引起的垂直地下水排。空间描绘的溶解相羽下降梯度的源相关的DNAPL源的横向和垂直位置。DNAPL源和向下梯度取样截面之间的距离可以从一些取样点的穿透曲线确定，但对于其他取样点则不能，因为在溶解实验期间DNAPL区的缓慢扩张持续了一段时间。
This paper describes some of the results from a field experiment at the Canadian Forces Base Borden, Ontario, Canada. Five liters of a chlorinated solvent mixture (2.0 L of trichloroethylene, 0.5 L of chloroform, and 2.5 L of tetrachloroethylene) was released into a sandy aquifer to create a heterogeneously distributed source. The dissolution and dissolved-phase plume development from this source were studied in detail along a cross-section downgradient of the source for a period of approximately 1 yr. At the conclusion of the experiment, the site was excavated to map the actual distribution of solvent residuals in the subsurface. Dissolved-phase concentrations exceeded 10% of the effective solubility of the individual components in the portion of the plume directly downgradient of the source, providing a strong indication of the presence of dense nonaqueous-phase liquids (DNAPLs). Dissolved-phase concentrations in several sampling points exceeded 50% of the effective solubility. However, even with detailed groundwater monitoring, it was not possible to determine the small-scale distribution of the DNAPL source. Lower dissolved concentrations occurred deeper than the DNAPL source zone, likely as a result of vertical groundwater Row caused by fluctuations in the water table elevation. Spatial delineation of the dissolved-phase plume downgradient of the source correlated generally to the lateral and vertical location of the DNAPL source. The distance between the DNAPL source and the downgradient sampling cross section could be determined from breakthrough curves for some of the sampling points but not for others because slow expansion of the DNAPL zone continued for some time during the dissolution experiment.