Formatted Title
A Permanent Ground Portal for Nondestructive HRSC UV Visualization of LNAPL Soil Contamination: From Lab to Field Studies
Background/Objectives
High resolution site characterization (HRSC) tools provide detailed vertical mapping of contaminant distributions in the ground. Additionally, some HRSC tools also provide lithology data. These HRSC vertical profiles of contaminant concentrations and soil properties enable a more complete LNAPL conceptual site model (CSM). Due to high mobilization costs related to heavy equipment associated with the HRSC probes, HRSC surveys are typically generated once, However, the parameters surveyed change in time due to complex interactions between contaminant, water soil saturations, groundwater levels, and lithology. This presentation will describe a novel tool that can repeat vertical surveys, adding a time-dependent dimension to HRSC data at a temporal density prohibitive to current methods.
Approach/Activities
E-Flux has developed a technique to install a monitoring port into a soil boring that can be repeatedly surveyed using HRSC UV-based imaging techniques, enabling the measurement of changes in soil LNPAL distributions and collection of lithology data. The port consists of a dry, solid well casing including transparent sections. A device is deployed in this clear dry well casing that shines UV and visible light into the formation, revealing detailed pore-scale distributions of LNAPL and soil granulometry data. The data is processed to create continuous vertical digital images and LNAPL saturation profiles that reflect current soil water and contaminant distributions.
Results/Lessons Learned
This presentation will include lessons learned from laboratory experiments about conditions that can lead to LNAPL redistributions in the soil, under different lithology settings and groundwater level changes. In addition to laboratory data, two field studies will be described. Survey results will be contrasted with traditional data from LNAPL thickness in monitoring wells.