Fundamental Evaluation of Tracer Techniques for Characterizatiion of Non-Aqueous Phase Liquids (NAPLs) Retention Volumes in Heterogeneous Aquifers

与地下非水相液体（NAPL）的检测和定量相关的困难促使开发了利用分区和界面示踪剂的创新的、侵入性较小的场地表征方法。 虽然这些技术已在美国和欧洲的许多油田现场使用，但目前的应用仅限于处于或接近残余饱和度的NAPL。 据推测，这些示踪剂的组合使用也可能是有用的，用于确定发生偏离的情况下，如孤立的游泳池和宏观圈闭区，发生在自然异质地下地层的剩余饱和度。 本研究的目的是评估的行为分区，界面和保守的示踪剂在水饱和的地下系统中，NAPLs被困在自然异质性的条件下。将解决以下研究问题：地下非均质性对NAPL分布的影响将导致示踪剂的行为，不一定是由局部平衡，一个假设，经常用于分析示踪剂数据控制。 然而，在自然非均质性下的NAPL截留可能具有独特的、可识别的示踪剂特征，即使在非平衡条件下。 这些独特的签名可以是可区分的，用于解析和表征复杂的NAPL发生。放大的NAPLs的现场行为有很大的不同，在一维柱实验中观察到的，特别是当介质的异质性引入。 解决示踪剂在更大的空间尺度和增加的维度的行为的能力，可能会导致理论结构的细化和计算方法的改进，用于表征复杂的NAPL分布在该领域。该方法包括两个实验研究进行的列，细胞和中等规模的土壤罐和示踪剂数据分析的方法，使用改进的数值模型的发展。本研究既具有内在的科学价值，在测量和评估的基本参数，以及实际意义的非水污染物检测，修复和风险评估。

0107095IllangasekareDifficulties associated with the detection and quantification of non-aqueous phase liquids (NAPLs) in the subsurface have prompted the development of innovative, less-intrusive site characterization methods that utilize partitioning and interfacial tracers. Although these techniques have been utilized at many field sites in USA and Europe, current application is limited to NAPLs that are at or near residual saturation. It is hypothesized that the combined use of these tracers may also be useful for identifying occurrences that diverge from cases of residual saturation such as isolated pools and macro-entrapment zones that occur in naturally heterogeneous subsurface formations. The goal of this research is to evaluate the behavior of partitioning, interfacial, and conservative tracers in water-saturated subsurface systems where NAPLs are entrapped under conditions of natural heterogeneity. The following research issues will be addressed: The influence of subsurface heterogeneity on the distribution of NAPL will result in tracer behavior that is not necessarily controlled by local equilibrium, an assumption that is frequently used in analyzing tracer data. However, NAPL entrapment under natural heterogeneity may have unique, identifiable tracer signatures, even under non-equilibrium conditions. These unique signatures may be distinguishable for resolving and characterizing complex NAPL occurrences. The up-scaled field behavior of NAPLs differs considerably from what is observed in one-dimensional column experiments, particularly when media heterogeneity is introduced. The ability to resolve the behavior of tracers at larger spatial scales and added dimensionality may lead to refinements in theoretical constructs and improvements in computational methods for characterizing complex NAPL distribution in the field. The approach consists of both experimental studies conducted in columns, cells and intermediate-scale soil tanks and development of methods for tracer data analysis using improved numerical models. This research has both intrinsic scientific merit in terms of the measurement and evaluation of fundamental parameters as well as practical implication for NAPL detection, remediation, and risk assessment.