And, What is this FVD Data good for??

Emitted light returns to the surface and is split across a light spectrum, separated by wavelength. This light is then analyzed by a digital oscilloscope. The UVOST is set-up so oscilloscope quantifies the emitted light within the 340-nm, 390-nm, 440-nm, and 490-nm wavelength channels. Each waveform exhibits an individual height and intensity within each wavelength channel. This provides a 4-waveform ‘fuel signature’. Data acquired by the UVOST is displayed in fluorescence vs. depth (FVD) logs. Fluorescence data is quantified as a percentage of Relative Emittance (%RE). The signal strength is a percentage of a known standard (M1 Standard). This quantitative analysis allows the UVOST data to be comparable to more traditional laboratory analysis contaminant concentrations (such as ppm).

Below is an example of an FVD Log (Please excuse the poor resolution, I'm working on my web-site creating abilities).  The %RE is shown as a quantatative measure at each depth interval.  The corresponding color of the %RE is representative of the waveform.  The 'Callouts' (on the Left side of the Log) are the actual fuel signature waveforms at points chosen by the user; the individual waveform at any recorded depth came by displayed in the log as a Callout.



An individual waveform is recorded every 1-second. By using a rate-control device with the direct-push drill equipment, the push-rate can be set to 2-cm per second. This results in a data density of a data point per every 2-cm. The coupling of the waveforms to a recorded depth, 3-dimensional data analysis is acquired. This 3-dimensional data acquisition can be used with the latest modeling software to provide 3-D Plume Mapping. 3-D Plume mapping can be used for multiple purposes. It is ideal for minimizing efforts in remedial actions such as soil removals and in-situ treatment systems. It also can be used to predict subsurface plume mobilization or maximize closure sampling.