Passive Diffusion Sampling
Diffusion sampling, is a form of groundwater sampling using passive diffusion bags (PDB). This method leverages the natural process of molecular diffusion to collect groundwater samples without the need for pumping, thus offering a less invasive, cost-effective, and technically efficient alternative to traditional groundwater sampling techniques like bailing, pump-and-purge or low-flow sampling.
There are two types of diffusion samplers: PDBs and Dual Membrane Passive Diffusion Bags (DMPDB).
- PDBs like EON’s Equilibrator sample for Volatile Organic Compounds (VOCs) in groundwater.
- DMPDBs sample for all contaminants including PFAS.
EON manufactures and offers the most frequently used PDBs in our industry. We were the first to commercialize passive diffusion sampling in 1998 – and we continue to stay on the forefront of the knowledge and products of this field. Learn more about diffusion sampling.
More information About PDBs
Bunnell-Lammons Engineering Study (1998) – Field Trial of a New Commercially Available Diffusive Ground-Water Sampler by Andrew Alexander and Thomas Lammons (equilibrator introduced in study).
McClellan Air Force Base (2001) – A recent study that compares cost, ease of use, and analytical results of samples collected by diffusion sampling and low-flow methods (equilibrator shown effective).
USGS/EPA Guidance Document (2001) – Federal and State Agencies publish a Guidance Document for the use of Passive Diffusion Sampling.
ITRC Tech-Reg Document (2002) – Recommendations on the Use of Polyethylene Diffusion Bag Samplers for Long Term Monitoring of Volatile Organic Compounds in Groundwater by Inter-State Technical Regulatory Council.
ITRC Final Report (2004) – Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in Groundwater by Inter-State Technical Regulatory Council. This is an aid to regulators and users to determine the applications and use of PDBs.
Filling Instructions – Instructions for filling the EON Equilibrator PDB sampler.
Tether Installation – Instructions for installing one or more Equilibrator PDBs on a single tether.
Hanger Installation – Instructions for installing one Equilibrator PDB using the EON stainless steel Hanger.
Adjusting SST Tether Ring – Instructions for relocating adjustable rings on stainless steel tethers.
PowerPoint Presentation – A PowerPoint Presentation with basic information in graphical format describing the technical basis, applications, configuration and installation of PDBs in graphical format.