Overview
Dakota Technologies (Dakota) provides state-of-the-art services for hazardous waste site investigations, specializing in the rapid site assessment of subsurface LNAPL and multi-component DNAPL. Incorporated in 1993, Dakota has an experienced staff with over 100 years of combined experience in developing and deploying direct push screening tools for site investigations.
Chlorinated solvents and petroleum hydrocarbons have contaminated subsurface soils and groundwater at thousands of sites all over the world. Traditional methods of determining the presence and extent of light non-aqueous phase liquid (LNAPL) and dense non-aqueous phase liquid (DNAPL) contamination are time consuming and costly, and may not be able to differentiate between contaminant phases. Laser-induced fluorescence (LIF) employs laser light to excite fluorescent molecules contained in the vast majority of hazardous NAPLs including petroleum fuels/oils, coal tars and creosotes. Additionally, through the use of a new dye-enhanced LIF technique, standard LIF tooling is now used to detect dye-labelled DNAPL chlorinated solvents. Direct push logging of the NAPL’s inherent fluorescence with depth provides rapid and reliable identification and delineation of NAPL. Multiple LIF logs completed at NAPL release sites provide a relatively non-subjective basis for a detailed NAPL conceptual site model (CSM).
Three LIF systems have been developed by Dakota Technologies to identify the presence, nature and extent of LNAPL and DNAPL at contaminated sites: Ultra-Violet Optical Screening Tool (UVOST®) for Petroleum, Oil, and Lubricants (POLs); Tar-Specific Optical Screening Tool (TarGOST®) for Coal Tars, Heavy Crudes, Creosotes; and Dye-Enhanced Laser Induced Fluorescence (DyeLIFTM) for DNAPL chlorinated solvents. All three LIF technologies collect and record data in-situ at high resolution, obtaining continuous readings while being advanced into the subsurface at a rate of approximately 2 cm/second. The result is a continuous data set with no data gaps such as those that are often experienced with traditional sampling methods due to poor sample recovery.