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| Resource Library > Technology Transfer > Programs and Initiatives > Diffusion Samplers > Overview |
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The passive diffusion sampler is a relatively new technology that was designed as an inexpensive approach for long-term groundwater monitoring to minimize labor costs and waste generation (i.e., well purge water) while providing samples that equal or better the representation provided by the standard purge and sample methods.
The diffusion sampler technology utilizes a deionized water-filled, low-density polyethylene diffusion membrane to collect water samples from groundwater monitoring wells. VOCs in the groundwater diffuse into the deionized water contained in the sampling bag. Chemical equilibrium between the groundwater and sampler water typically occurs within 14 days, providing a water sample that is representative of VOC concentrations in the well water. Diffusion samplers can be used to easily and inexpensively obtain groundwater samples for VOCs in monitoring wells (Vroblesky et al., 1996; Vroblesky and Hyde, 1997). When used appropriately, representative groundwater samples can be obtained without well purging to identify temporal changes in well water chemistry (Vroblesky et al., 1996).
Diffusion samplers provide the potential for significant cost savings at facilities where long-term monitoring of groundwater is being conducted. In particular the diffusion sampler technology can potentially reduce or eliminate costs associated with conventional well purging and micropurging, including labor, equipment, and purge water disposal.
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