WWEM - Abstract

Abstract Information :

Groundwater sampling is a key piece of many environmental protection programs, ranging from detection monitoring at landfills and industrial sites to performance monitoring at contaminated land sites to assess the efficacy of remediation efforts and sentinel well monitoring for water supply protection. Groundwater sampling systems are available in a wide variety of types and designs such as submersible pumps, peristaltic pumps, grab samplers and bailer, and various passive sampling devices. They can be portable systems that are transported between boreholes on a site and cleaned after each use or dedicated systems with equipment that remains in the borehole between uses, eliminating the need to transport, set up and clean equipment between uses. Much of this equipment has historically been manufactured using “Teflon” (fluoropolymer) components. Fluoropolymers offer a robust combination of being chemically inert, non-reactive, gas impermeable, flexible and durable. Sampling systems use fluoropolymer materials for pump bladders, tubing, bottle caps, seals, O-rings, wire insulation and more, based largely on regulatory guidance. Installing fluoropolymer systems has traditionally been viewed by regulators as best practice, streamlining permit reviews and regulatory compliance audits. Now, however, the use of fluoropolymers in sampling equipment has been called into questions with the need to sample groundwater to look for per-and polyfluoroalkyl substances or “PFAS.” PFAS have been used in the manufacturing of a wide range of consumer and industrial products for several decades, including aqueous firefighting foam (AFFF), building construction and roofing materials, cleaning products, paints and varnishes, personal care products, and many more. This widespread use has resulted in PFAS being detected in surface waters, ground water and soils around the world. Wide distribution of PFAS in the environment combined with very low analytical detection capability in the sub part per trillion range make it challenging to isolate PFAS that is present in water systems from samples contaminated by other sources. Sampling equipment made from fluoropolymer components once lauded by regulators as the gold standard is viewed with suspicion and concern. Regulatory and industry guidance for PFAS sampling often recommends the elimination of all fluoropolymer components. This conservative position poses a challenge to site operators with existing sampling systems who are wondering if their equipment could be a source of PFAS and if they might be faced with replacing those systems at considerable expense. Sampling equipment manufacturers see an engineering challenge to find alternate materials that can match the performance of fluoropolymers while also not creating a source of other potential organic contaminants. But is this conservative approach really necessary? Materials testing by a over the past several years has shown that most fluoropolymer materials do not leach PFAS into water samples, and field testing has shown than many existing dedicated sampling systems are not sources of PFAS. This presentation explores the challenge of sampling groundwater for PFAS and explains some of the myths around the use of fluoropolymers in sampling systems. It will also offer recommendations on a path forward for both site operators and regulators faced with the challenge of PFAS sampling.