For over a decade or more passive diffusion bag samplers (PDBS) have increasingly become a technique for a no purge sampling approach. PDBS are semi-permeable low-density poly-ethylene bags filled with clean distilled deionized (DI) water which can allow Volatile Organic Compounds (VOCs) to diffuse across the bag. VOCs in groundwater diffuse through the bag into the DI water and reach equilibrium with the surrounding groundwater. The use of PDBS has been applied for sites containing low-yielding monitoring wells or as a cost-effective alternative on long-term monitoring programs compared to conventional (standard and low-flow sampling) techniques. In either case, the use of PDBS is not without consideration for their limitations which include site contaminants of concern, monitoring well screen or open bore hole length, and correlation of analytical results compared to conventional sampling techniques.
JMS recognizes that PDBS may be appropriate for some but not all sites or even from well to well at the same site. We recommend when evaluating PDBS at sites to consider the cleanup goals for a project and review of applicable guidance from State and National/Federal agencies (New Jersey Department of Environmental Protection, Interstate Technology and Regulatory Council, United States Geological Survey, United States Army Corps of Engineers, and United States Environmental Protection Agency).
The application of PDBS vs. conventional sampling techniques may affect your site and timing to achieve your cleanup goals. Please feel free to contact our office for assistance or if you have questions on the application of PDBS, costs and performance, lessons learned, low-yield sites, long-term monitoring, and applicable compounds appropriate for PDBS.
JM Sorge, Inc.