Introduction of Per- and Polyfluorinated Substances into Groundwater Samples Using Industry-Standard Sampling Equipment

Per- and polyfluoroalkyl substances (PFAS) have emerged in the environmental arena as unexpected groundwater contaminants, potentially present at many existing sites worldwide. Because of increased regulatory awareness, groundwater sampling will be increasingly performed in the future to assess the nature and extent of groundwater impacts from these emerging contaminants. Unfortunately, the chemical characteristics that made PFAS such excellent products for consumer and industrial use, including low coefficient of friction, hydrophobicity, and lack of sorption to organic materials, make them ideal products for construction and coatings for environmental sampling equipment. Many impeller pumps and bladder pumps contain or are coated with fluoropolymers and fluorotelomers, such as Teflon and Viton. Internal parts include O-rings, seals, impellers, bladders, thrust washers, wear plates, and wire jackets and sample tubing is often coated as well. Many of these parts contact the groundwater sample during collection and have the potential to introduce low-level contamination that may be incorrectly attributed to the facility or aquifer. With regulatory standards in the sub-part per billion range, such as New Jersey’s 0.04 µg/L drinking water regulatory criteria, introduction of low levels of PFAS into a sample could lead to unnecessary regulatory alarm and possible remedial actions.

Equipment blanks were created using the most common sampling equipment by exposing the equipment to Type II Reagent Grade distilled water, collecting the water in Teflon-free sample bottles, and analyzing the samples for a defined list of PFAS at Oregon State University’s analytical laboratory. Detailed analytical data will be presented for the six PFAS that are on the US EPA’s Unregulated Condiment Monitoring Rule 3 (UCMR3) and recommendations will be provided to ensure that samples collected are representative of the subsurface groundwater conditions and not the sampling equipment utilized.