Nonaqueous Phase Liquid (NAPL)

Anchor QEA leads the industry in evaluating NAPL mobility in sediment, and we also have extensive experience with NAPL in soil and bedrock. We quantify the influence of NAPL in terms of risk and develop protective, full-scale remedies that withstand the test of time. Our team has decades of experience at numerous, high-profile sites with NAPL in sediments and adjoining uplands throughout the United States and in Canada. We participate on multiple ASTM International (ASTM) working groups that are actively developing four guidance documents regarding NAPL delineation, mobility, and migration, including advection and gas ebullition. We apply the best technologies to characterize the 3D NAPL distribution, including detailed core photography with ultraviolet light, laser-induced fluorescence, in-field NAPL mobility screening tests, and 2D and 3D visualization tools to depict the extent and magnitude of the presence of NAPL.

Where Anchor QEA differentiates itself the most is in quantifying the mass fluxes associated with NAPLs, which are crucial for risk and remedial alternatives assessment and design. For example, with regard to “advective” NAPL flux, Anchor QEA’s NAPL mobility experts have developed and successfully applied an innovative, multiple-lines-of-evidence protocol, including NAPL saturation and hydraulic conductivity, to quantify NAPL mobility under field conditions using laboratory NAPL mobility tests with sediment cores containing NAPL. The methods we developed are included in pending ASTM guidance. The presence of any NAPL in a porewater or groundwater sample produces extreme overestimation of true aqueous concentrations. Anchor QEA solved this problem by pioneering the use of porous ceramic filters to collect pure aqueous samples in direct contact with NAPL in sediment, with no NAPL or sheen in the analyzed porewater. We have successfully applied this method with a variety of porewater sampling methods at six high-profile sites across the United States and in Canada.

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