Objective:

Long-term groundwater sampling programs, required to assess contaminant trends in groundwater and risk to human health, are becoming exceedingly costly. Passive sampling techniques such as use of the polyethylene passive-diffusion bag (PDB) sampler have been developed and are gaining acceptance within the scientific and regulatory community. These methods can provide considerable cost savings over conventional low-flow purging and sampling methods. It is estimated that the potential cost savings using passive techniques for long-term monitoring at Department of Defense (DoD) facilities is on the order of 70% compared to conventional low-flow purging and sampling. Recently, similar cost savings (60 to 70%) were found using the Snap Sampler and the Regenerated Cellulose Membrane sampler to sample inorganic analytes (including metals). The objective of this project is to demonstrate the utility, sensitivity, comparability, and potential cost savings of passive groundwater sampling using the Gore Module. Emphasis will be placed on the improved sensitivity that can be achieved using this device (i.e., better plume delineation).

Technology Description:

The Gore Module, developed by W. L. Gore & Associates, Inc., can be used to sample a wide variety of volatile organic compounds (VOC) and semi-volatile organic compounds (SVOC), including water-soluble oxygenates, 1,4-dioxane, chlorinated compounds, fuel-related compounds, some explosives, chemical warfare agent breakdown compounds, and polycyclic aromatic hydrocarbons (PAH). The sampler consists of a tube of GORE-TEX membrane, which is chemically inert, vapor permeable, and waterproof. Housed inside the membrane are sorbents that have an affinity for a broad range of VOCs and SVOCs. Analytes with sufficient volatility partition from the aqueous phase to the vapor phase, diffuse through the membrane, and are sorbed by the sorbent. Analyses are then conducted by the Gore laboratory using thermal desorption gas chromatography/mass spectrometry (GC/MS) and standard Environmental Protection Agency (EPA) methods for VOCs and SVOCs. These samplers can be deployed in any well or piezometer with a diameter greater than 0.25 inches. High resolution vertical profiling can be achieved by placing the samplers at multiple sample depths.

Expected Benefits:

Benefits for the DoD and the Department of Energy (DOE) associated with using this sampler include better plume delineation (which can result in more effective and less costly remediation) and substantially reduced costs for long-term monitoring (estimated to be in the range of 26% to 70%). These samplers can also be used to detect very low levels of contamination (in the part per trillion range) and thus can provide an early warning of contaminant migration from a site. (Anticipated Project Completion - 2013)

Principal Investigator:

Ms. Louise Parker
U.S. Army Engineer Research and Development Center
Cold Regions Research and Engineering Laboratory
72 Lyme Road
Hanover, NH 03755-1290
Telephone: (603) 646-4393
Fax: (603) 646-4640
E-mail: louise.v.parker@usace.army.mil