PFAS, or Per- and Polyfluoroalkyl Substances, are compounds that have become of increasing concern around the globe because their use and persistence has resulted in a legacy of environmental contamination and a potential for risk to human health and the environment.
Because of their unique properties, PFAS have been widely used worldwide for over half a century in industrial applications and products in all sectors of the economy including infrastructure, manufacturing, oil and gas and mining. They can also be found in a variety of household items, from carpeting, to food wrappers, to apparel and other products.
One of the most prevalent applications of PFAS is in firefighting training areas (FTAs) on airport sites. Recently, our team* was called upon by a government department to perform a desktop screening and ranking of approximately 100 airports to prioritize future PFAS investigations related to impacts from FTAs. The screening tool was based on the answers to some 40 questions related to historical records on PFAS use and site conditions. These questions included areas such as FTA construction, infrastructure and use; hydrology / hydrogeology and associated contaminant transport; presence, type of and distance to receptors; and stakeholders’ involvement.
The screening tool ultimately provided a numeric classification score for each FTA (the higher the score, the more likelihood of PFAS impacting human or ecological receptors, or properties). For each site, a summary sheet was developed to consolidate key data identified during the desktop review, to produce a concise conceptual site model describing PFAS sources, transport and potential receptors, and to establish preliminary investigation locations for all the applicable environmental media.
Some of the most important information for the site risk ranking was identified as:
- Quantity of Aqueous Film Forming Foam (AFFF) used and duration of discharg.
- Potential for secondary sources of PFAS
- Discharge locations (lined/unlined)
- Presence of surface water features
- Water wells or sensitive aquifers with respect to contaminant transport,
- Historic remediation (positive or negative consequences, but often negative),
- Presence of sensitive human and ecological receptors.
The client used the results of this screening and ranking to assist with liability identification, management and reduction. Based on the ranking, sites were prioritized for investigation in the short term, or medium to long term, and some sites were removed from the investigation list based on the negligible potential for impacts.
This proactive approach helped to gain greater confidence from stakeholders, and solve compliance issues with regulators.
* This work was performed by Golder professionals who joined WSP in an acquisition completed in 2021.