Introduction
Dakota has developed the Tar-specific Green Optical Screening Tool or TarGOST®. TarGOST was developed exclusively for detection of coal tars, creosotes, heavy crudes, and tank bottoms. Following a comprehensive spectroscopic study of coal tar behavior, Dakota created this method which results in a monotonic response for coal tars on a variety of soils. Lab tests of TarGOST indicate the system is ideally suited for delineating the NAPL contaminated zones or source term at former manufactured gas plants (MGPs) and wood treating facilities.
Utilizing TarGOST
The TarGOST system is designed specifically to overcome the low signal levels and often severe non-monotonic response observed on coal tars and creosotes with current UV-based fluorescence systems. TarGOST does not have the detection limits typically observed with the UV-based UVOST on the lighter molecular weight NAPLs, rather TarGOST focuses solely on mapping higher molecular weight NAPL contamination (LOD = ~100-500 ppm NAPL on soil).
TarGOST has been confirmed to be useful for logging:
- Coal tar (coking, former manufactured gas plants, etc.)
- Creosote
- Crude oil
- Bunker
- Heavy distillate
- Dripolene (olefin plant aromatic byproduct)
- DEHP/BEHP (some - not all)
- Biodiesel
Dakota is currently offering TarGOST site characterization service of former manufactured gas plants (MGPs) and wood-treating facilities. Since the first full-scale site characterization project in June of 2003, the system has been successfully applied and validated in a wide variety of site conditions and deployment platforms, including direct push technology and cone penetration testing (CPT) rigs. Barge deployment is now becoming fairly routine and continues to be a growing deployment platform for TarGOST.
Successful remediation/treatment systems require detailed knowledge of the NAPL distribution. TarGOST provides this knowledge at unprecedented speed, detail, and efficiency.
TarGOST+HP
The new TarGOST+HP tool enables the practitioner to efficiently delineate coal tar and creosote DNAPL while simultaneously classifying the scales of lithologic variability that control mass storage and transport in the source and distal segments of the DNAPL plume. This unique combination of technologies in a single tool reduces time and cost, while eliminating the need to integrate TarGOST and HPT data from adjacent borings.