You are here:
MEASUREMENT AND USE OF CONTAMINANT FLUX AS AN ASSESSMENT TOOL FOR DNAPL REMEDIAL PERFORMANCE
Citation:
BROOKS, M., C. G. ENFIELD, A. L. WOOD, AND M. D. ANNABLE. MEASUREMENT AND USE OF CONTAMINANT FLUX AS AN ASSESSMENT TOOL FOR DNAPL REMEDIAL PERFORMANCE. Presented at 2005 Clemson Hydrogeology Symposium, Clemson, SC, April 13 - 15, 2005.
Impact/Purpose:
To inform the public.
Description:
Current remedial techniques are unable to completely eliminate all dense nonaqueous phase liquid (DNAPL) from source zone areas at most sites, and conflicting views on the benefits of partial DNAPL source zone remediation exist in the literature. A comparison of contaminant flux measurements before and after remedial activities is one metric that has been proposed to elucidate benefits of partial DNAPL removal. Historically, contaminant flux has been estimated from distinct field measurements of hydraulic gradient, hydraulic conductivity, and contaminant concentration. The objective of this work is to investigate the use of integrated pump tests (IPT) for field flux measurements. This technique consists of extracting water from a series of wells aligned perpendicular to the groundwater flow direction. Analytical solutions to pumping well(s) in a uniform flow field are used with head measurements and pumping rates to directly estimate the Darcy velocity (without independent estimates of hydraulic gradient and hydraulic conductivity), which is used with analytical chemistry results to estimate the contaminant flux. The IPT technique has been implemented at DNAPL field sites in Seattle, Washington; Borden, Ontario, Canada; Jacksonville, Florida; and Hill Air Force Base, Utah. A variety of remediation technologies are being used to treat DNAPL source zones at these sites including in-situ flushing, resistive heating and in-situ oxidation. Results from IPT deployments at these sites will be presented and compared to results of an independent flux measurement technique based on tracer-laden absorbent material placed in the same wells. Although these techniques measure flux over different spatial scales, results to date suggest order-of-magnitude or better agreement. Additional field tests of these techniques are planned.