Diffusion/Passive Samplers

The ultimate goal of the Diffusion/Passive Samplers Team is for state environmental agencies to alter their policies to enable responsible parties to more easily choose to use passive samplers under appropriate circumstances. Many policies are biased toward purge sampling, which may require side-by-side comparison studies with passive devices to purge techniques or compare passive sampling results with historical results from purge techniques. While not insurmountable hurdles, these policies do lay the burden on users to justify their choice of using passive samplers.   According to 16 state agencies, responding to a team questionnaire, there are no specific regulatory barriers to using passive samplers to collect ground water samples.

The purpose of the team's documents is to encourage the appropriate use of passive sampler technologies in new ground water monitoring programs and as a replacement for existing volume purge sampling systems. Ultimately, promoting state acceptance to the point where states issue their own guidance for the appropriate use of passive samplers. The documents produced include:

Team leader Kim Ward from New Jersey DEP says, “If we provide the information, then acceptance will come, facilitating the nationwide use of these devices under appropriate conditions, because it is a cost-effective means of collecting a formation quality groundwater sample, that can improve states’ ability to protect human health and the environment.”

All these passive samplers;

  • are relatively easy to use,
  • eliminate purge-water production; therefore, little or no disposal cost,
  • reduce field sampling variability resulting in highly reproducible data,
  • decrease field labor and project management costs for long-term monitoring,
  • allow rapid field sample collection,
  • can sample discrete intervals in a well,
  • are practical for use where access is difficult or where discretion is desirable,
  • can be deployed in series to provide a vertical contaminant profile,
  • can be deployed in most wells, and
  • have no depth limit

Passive samplers acquire a sample from a discrete position within a well, must remain submerged during a deployment period and collect formation-quality water samples in ambient equilibrium with ground water (formation water) with little or no well-water agitation. Passive samplers can be deployed at any location within the screened interval to evaluate the highest or lowest contaminant concentration in a stratified flow screened interval.   By deploying a series of samplers within the screened interval, passive samplers can also provide a contaminant concentration profile of a screened interval of a well.