Objective:

Sampling of groundwater for long-term monitoring or site assessment at Department of Defense (DoD) remediation sites can be very costly using conventional methods such as well purging. Also, increased groundwater turbidity created during conventional sampling can produce bias due to the sorption of contaminants onto suspended particulates. In-well diffusion samplers recently have been developed and show promise for greatly reducing sampling equipment, production/treatment of purge water, and skilled labor costs. Unfortunately, the only low-cost diffusion sampler validated and commercialized to date is the polyethylene bag sampler. Polyethylene bags initially contain pure water and work well for measuring volatile organic compounds (VOCs), but they are not useful for many common soluble groundwater parameters (e.g., metals, MTBE, semi-volatile organics, and MNA parameters). This project will demonstrate the use of low-cost, regenerated cellulose (dialysis) bag samplers for measuring a broad range of soluble contaminants and other chemical parameters in groundwater and will determine the shortest appropriate equilibration period.

Technology Description:

Regenerated cellulose diffusion bag samplers will be demonstrated in the following three phases: (1) initial assessment of field sites and groundwater collection for bench-scale testing; (2) bench-scale evaluations to assess samplers under static groundwater conditions; and (3) field demonstrations at sites used for bench-scale tests to validate the performance and cost of the technology. Demonstrations will be conducted at several field sites that have different contaminants and aquifer geochemistries. Field data will be compared to conventional low-flow groundwater sampling, discrete horizon sampling, and polyethylene bag sampling (for VOCs only). Long-term stability of the dialysis bag samplers will also be determined.

Expected Benefits:

An earlier, more limited, field demonstration of the dialysis bag samplers indicated cost savings of up to 50 percent, when compared to conventional (high- and low-flow) groundwater sampling. Unlike the polyethylene bag samplers, the new samplers can potentially equilibrate with all soluble parameters present in groundwater. The diffusion bags also eliminate analytical problems posed by suspended particles since these do not pass through the diffusion membrane. Use of diffusion bag samplers requires minimal training, is less intrusive, and avoids cross-contamination, variability, or dilution of samples that is often encountered with active sampling methods. (Anticipated Project Completion - 2007)

Contact:
Mr. Joey Trotsky
Naval Facilities Engineering Service Center
1100 23rd Avenue, Code 411
Port Hueneme, CA 93043
Telephone: (805) 982-1258
Fax: (805) 982-4304
E-mail: joey.trotsky@navy.mil