The Ultra Violet Optical Screening Tool (UVOST) is a direct-push screening tool that uses patented Laser Induced Fluorescence (LIF) technology and efficiently delineates petroleum, oil, and lubricant (POL) contaminants in the subsurface. All the usual forms of POLs, including; gasoline, diesel fuel, jet fuel, and hydraulic fluids, can be detected via the response of their polycyclic aromatic hydrocarbon (PAH) constituents that are typically found within the Non-Aqueous Phase Liquid (NAPL). The fluorescence signal scales proportionally with NAPL concentration (i.e., the more impacts in the subsurface the higher the response). UVOST’s LIF technique, in conjunction with direct push deployment, yields a detailed three-dimensional map of the NAPL distribution, in real time.
Benefits for using the UVOST include;
- Typical detection limit of 10-500 ppm (NAPL type and soil dependent)
- Works in both saturated and unsaturated soils of varying types (ie. clay/silt to sand/gravel)
- Operates effectively above and below the saturated zone
- Probe advances at ~2 cm/sec without pause
- Typical daily productivity of 75 to 90 meters across 10-20 locations
- Centimeter resolution data density coupled with nearly instantaneous response provides continuous detailed log of product distribution and heterogeneity
- Color-coded logs for the ultimate in screening level qualitative information in real time
- Waveforms offer product identification/verification and rejection of non-contaminant fluorescence such as mineral, peat, and other minor interferences
The LIF laser is “calibrated” prior to each location being pushed which allows for maximum QA/QC assurances. The LIF technology also has the ability to log electrical conductivity (EC) that can be used to infer soil texture (i.e., clay content typically exhibits a higher conductivity). This is especially helpful when determining what soil type/horizon the NAPL is present at each location.