Limitations in the Use of Partitioning Tracers for Estimating the Volume and Distributions of NAPLS

Partitioning tracers offer a unique alternative to inefficient and expensive traditional methods of detecting NAPL contamination in the subsurface. In order for partitioning tracers to be effective, however, several assumptions must be true. One of the major assumptions is that once injected, the tracer will contact all of the NAPL present in the flow field. If this assumption is not reasonable, the result will be an underestimation of the true NAPL volume. This thesis looked at the impacts of NAPL distribution and average NAPL saturation of a porous medium on the ability of partitioning tracers to contact all of the NAPL present. Models of a simple homogeneous aquifer were developed using the Groundwater Modeling System (GMS). Partitioning tracer tests were then simulated using the FEMWATER flow and transport code. Simulations were performed for different types of NAPL distribution (i.e., ganglia and pools) and different average NAPL saturation values. The simulation results were used to develop concentration breakthrough curves for the tracer at the point of extraction