For half a century, a wide variety of industries have embraced Per-and Polyfluoroalkyl Substances (collectively known as PFAS) for their unique surfactant properties and their ability to repel oil and water.
This meant that these compounds have been used in a wide array of products, as diverse as fire-fighting foam, cleaning products, non-stick cookware, food packaging, cosmetics, and breathable outerwear. With the rising concerns about the potential impacts these substances can have on human health and the environment, PFAS have become a focus of concern in many parts of the world.
That was the case at an active manufacturing facility in the northeastern United States, where historical PFAS air emissions have led to investigations of soil, groundwater, stormwater, surface water sediment, and fish tissue.
WSP* conducts a region-wide PFAS investigation
As the primary environmental consultant, in association with a team of consultants, we are investigating PFAS impacts from multiple sources over several square miles. We have been leading the development of the conceptual site model (CSM), and potential additional on-site and off-site PFAS impacts and serves as the lead liaison with the state regulatory agency.
Investigations included extensive geologic and hydrogeologic investigations including geophysical surveying, installation, testing and sampling of over 40 overburden and bedrock monitoring wells, and collection of over 140 soil samples. We have also collected stormwater and surface water samples to evaluate PFAS concentrations in wet- and dry-weather flow within the facility’s stormwater management system, and in several nearby streams and rivers. As an extension of this work, our team has sampled sediment and fish tissue from nearby waterbodies.
Off-site investigations included soil sampling at multiple residential properties and sampling of hundreds of residential water supply wells. We are undertaking a more comprehensive program of sampling residential water supply wells and provision of interim alternative water.
Unique challenges of PFAS investigations
Because PFAS is so ubiquitous, special measures are required to prevent cross-contamination. Potential sources of PFAS cross-contamination include sampling equipment, clothing, footwear, personal hygiene products, and even food packaging.
For sample integrity, all investigation activities have been conducted under detailed work plans developed by our team which were accepted by the regulator with minimal comments.
A key focus of our service has been identifying and differentiating impacts from multiple PFAS sources in the large study area. The multiple-lines-of-evidence approach developed by our PFAS experts was used for this site. Through this approach, we have identified many other potential or known sources of PFAS impacts within the area of investigation including landfills, fire stations, airports, wastewater treatment facilities, composting facilities, manufacturing facilities and a variety of small commercial and industrial facilities.
Our services also include engagement with various public and private stakeholders, particularly residential property owners whose water wells are within the investigation area.
* This work was performed by Golder professionals who joined WSP in an acquisition completed in 2021.
