Chlorinated solvents, petroleum, creosote, and coal tars are common contaminants at thousands of sites all over the world. These “source term” light non-aqueous phase liquid (LNAPL) and dense non-aqueous phase liquid (DNAPL) contaminants are potent sources of dissolved phase contamination, making proper characterization of their subsurface architecture a keystone of long term remediation success. Unfortunately, these NAPL bodies typically distribute themselves in a highly heterogeneous fashion, leaving investigators with little alternative to gathering large data sets to understand their architecture, making traditional sampling and analysis costs prohibitively high.
Laser-induced fluorescence (LIF) is a cost-effective alternative to traditional sampling because it logs the NAPL continuously in the subsurface in real time. 250 to 450 feet/day production rates are typical, making characterization of NAPL bodies possible in just a few days’ to a weeks’ time. While LIF offers numerous benefits, it’s important that investigators understand LIF technology, what the LIF technology can and can’t tell them about their site, and how to avoid applying LIF to sites and conditions that can’t benefit from LIF.
The presenter, who is the lead developer of all LIF systems currently commercially available, will provide a brief summary of how LIF works, which LIF system to apply to which contaminant, what information LIF is capable of providing, along with its limitations.