Objective: The objective of this project is to demonstrate that passive (no-purge) groundwater sampling technology and the relatively newly developed Snap Sampler can provide technically defensible analytical data for the wide spectrum of analytes that are of concern to the Department of Defense (DoD) and can generate substantial cost savings. Technology Description: The Snap Sampler is a grab-type, passive groundwater sampling device that allows one to collect a whole (well) water sample under in situ conditions without agitating the well during sample collection. The device is deployed so that the ends of the sample bottle are open. When activated, the trigger releases Teflon-coated, spring-activated end caps that seal the bottle. Typically, after these samplers are deployed, the well is given time to re-equilibrate with the natural formation water flow-through in the well. This time also allows for the sampler materials to equilibrate with the contaminants in the groundwater (i.e., reduce any sorptive losses). Samples do not require transfer to another container after they are recovered from the well, thereby reducing the possibility of loss of volatiles or reaction with the air during transfer. Currently, 40-milliliter glass volatile organic analysis (VOA) vials and 125-milliliter glass and polypropylene bottles are available and compatible with standard analytical laboratory equipment. When larger sample volumes are required, multiple bottles can be deployed either in tandem on a single trigger line or on multiple trigger lines (depending on well diameter and sampling goals). For this demonstration, analyte concentrations in samples taken with the Snap Sampler will be compared with concentrations in samples taken using a standard low-flow purging and sampling method (EPA Region 1, 1996) and passive diffusion samplers such as the regenerated cellulose sampler (or dialysis bag sampler) and passive diffusion bag sampler. Using these three sampling technologies will allow comparison of dissolved and colloid-borne contaminants (such as metals and the more hydrophobic organic contaminants, including explosives). These studies will be conducted at five test sites encompassing a range of contaminants of interest to the DoD, including volatile organic compounds (VOC), explosives, perchlorate, metals, and natural attenuation parameters. Expected Benefits: Where the use of passive sampling is appropriate, data-quality improvements and cost reductions over low-flow sampling include better delineation of contamination with depth within the screened zone, reduced volumes of purge water waste, reduced labor during sampling, and reduced equipment costs. Previous studies have estimated that the potential cost savings using diffusion samplers for long-term monitoring at DoD facilities are on the order of 70% compared to low-flow groundwater sampling. Equilibrated grab-type samplers (like the Snap Sampler) can be used to obtain a real-time sample for any analyte type. The Snap Sampler is unique in that the sample is collected and remains under in situ conditions so there is no chance for interaction of the sample with water above the sampling zone or accidentally recovering stagnant water above the well screen as the device is brought to the surface. (Anticipated Project Completion - 2009) Principal Investigator: Ms. Louise Parker U.S. Army Corps of Engineers 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@erdc.usace.army.mil | 
