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The Dye-enhanced laser induced fluorescence system (DyeLIF) tool is a new site characterization technology that facilitates rapid, cost-effective 3-dimensional (3-D) delineation of residual chlorinated solvent DNAPL in the subsurface. DyeLIF is based on combining time-resolved LIF technology with the injection of a fluorescent dye ahead of the window to render non-fluorescent NAPLs fluorescent in-situ. This new technology has potential to rapidly delineate DNAPL source zones at sites where direct push is feasible, significantly improving prospects for targeted remediation. See links in Resources panel on this page for details regarding an ESTCP-funded technology demonstration conducted at a Formerly Used Defense (FUD) facility in Massachusetts in Fall 2013 (Geoprobe® delivery) and again in March 2014 (CPT delivery).


The probe functions by injecting an aqueous delivery fluid containing a proprietary hydrophobic dye through a small injection port that is situated below the LIF window. As the probe is advanced through the subsurface, the injected dye contacts the soil and quickly partitions into any present DNAPL. Standard LIF tooling is used to detect the dye-labeled chlorinated solvent DNAPLs. The fluorescent signature of un-solvated and solvated dye is sufficiently different.

Environmental Safety

The dye used with DyeLIF is not listed as a carcinogen by ACGIH, IARC, NTP, or CA Prop 65. The dye is not a DOT regulated material in the United States. Repeated or prolonged exposure is not known to aggravate any medical conditions. Dust is the main handling hazard but this form does not exist at the field site (it arrives in solution form). The dye is a skin and eye irritant so typical field level D PPE should be worn when handling the dye. The currently established injection rate of 1mg/second results in approximately 0.024 g injected with each foot of penetration (assuming 0.5 in/sec advancement rate) or just one gram for a 40 foot DyeLIF sounding.