Overview of FACT Method for a Continuous Profile of Dissolved Phase Contaminant Distribution in Fractured Rock

Key contaminated site characterization questions are: 1) where are the contaminants in the system; 2) where are the primary pathways for contaminant transport; and 3) how to limit effects of the borehole? A convenient answer is a sealing flexible borehole liner, which includes a NAPL sensitive cover on the liner, and also provides a high resolution profile of the dissolved phase contaminant distribution. This paper presents results of recent field testing of two technologies that can be deployed simultaneously on a FLUTe^TM liner. A NAPL FLUTe^TM color reactive cover plus an activated carbon felt strip sewn into the interior surface of the NAPL FLUTe cover maps the NAPL and the dissolved phase of contamination. The combination is called a NAPL/FACT.^TM FACT is short for the FLUTe Activated Carbon Technique*.The activated carbon felt strip adsorbs by diffusion the dissolved phase of the typical chlorinated solvents and also the daughter products. The carrier liner presses the FACT against the borehole wall, where the carbon felt wicks contaminants from both the pore space of the rock by diffusion and from groundwater flowing in fractures. After two weeks, the NAPL/FACT is recovered by inversion from the borehole. The carbon strip is sectioned into short intervals of generally 0.5-3 ft, which are sent to a lab for analysis using methanol or pentane extraction and a GC/MS system, with results reported as mass of each VOC per mass of dry felt. The NAPL FLUTe cover provides a 2-D map of the NAPL in vicinity of the borehole wall. This paper provides recent results of FACT measurements at the NAWC site near Trenton, NJ including comparison with multi-level water, core, head, and transmissivity profiles in the same borehole. Potential perturbations of the FACT results are addressed. More testing of the technology is ongoing as an ESTCP project