PFAS Site Characterization

PFAS have been detected everywhere, from fire­fight­ing training sites to industrial manu­fac­tur­ing facilities, landfills and wastewater treatment plants (WWTPs). And ongoing research continues to explore the inter­ac­tions between these chemicals and the environment, as well as with our own bodies. Promising treatment methods have been able to bring PFAS levels below federal and state regulatory thresholds, and some can even destroy the compounds entirely. But there is no one-size-fits-all treatment solution, and a better solution will rely on a better under­stand­ing of the char­ac­ter­is­tics of PFAS, their behaviors in the environment and their effec­tive­ness protecting sensitive receptors. 

Common Sources of PFAS Occurrence in the Environment

The Interstate Technology Regulatory Council (ITRC) identifies four major PFAS sources:

Fire training and response sites: Cont­a­m­i­na­tion originates from aqueous film-forming foams (AFFFs), a fire-extin­guish­ing mixture used by the military, oil refineries, municipal airports and fire stations. AFFF contains highly diverse mixtures of PFAS.

Industrial sites: These include manu­fac­tur­ing facilities that synthesized products containing PFAS, as well as secondary manu­fac­tur­ing facilities, which use PFAS as a coating for finished products. Wind directions and atmospheric deposition play key roles in trans­port­ing PFAS from industrial manu­fac­tur­ing sites. PFAS can be detected in soil and water up- and down-gradient from the facility.

Landfills: Industrial waste and consumer goods treated with non-stick coatings can all terminate in landfills and ultimately groundwater. Unlined landfills are more likely to dispel PFAS into groundwater, which can happen steadily over decades. These are mostly shorter-chain PFAS, which differ from those found at industrial and fire training sites.

Wastewater treatment plants and biosolids: Possible reasons for PFAS occurring at WWTPs include PFAS concen­tra­tions in solid waste and the oxidation of PFAS precursors during the treatment process. 

Analytical Tools for Site Char­ac­ter­i­za­tion

A phased approach is typical for PFAS site char­ac­ter­i­za­tion. Phase 1 may be to identify the presence of PFAS in suspected source area(s) at a site and their impact on drinking water sources. Phase 2 typically inves­ti­gates point and non-point sources at a site and if these sources have migration pathways contribut­ing to the drinking water sources. Phase 3 can involve further delineation of PFAS sources and their on-site and off-site extents. Phase 4 can be remedial inves­ti­ga­tion through collection of site-specific hydro­ge­o­log­i­cal conditions, geochemical conditions, precursor trans­for­ma­tion potential and remedial option evaluation.  

Ongoing Research

Researchers continue to study PFAS mass storage, mass discharge, migration patterns and how they respond to envi­ron­men­tal conditions and other co-cont­a­m­i­nants. While analytical method detections continue to drop and state-level health advisory levels get more stringent (see Table 4 of ITRC PFAS fact sheet Regulations), the persistence and mobility of these cont­a­m­i­nants pose significant challenges for site char­ac­ter­i­za­tion. Other challenges include veri­fi­ca­tions of ambient PFAS levels and the presence of multiple point and non-point sources at a site. Techniques that can be used to differ­en­ti­ate PFAS sources are under early stage of development. 

With in-house PFAS testing capa­bil­i­ties, CDM Smith is actively involved in developing PFAS property data, verifying PFAS trans­for­ma­tion potential and working with academic partners to combine different PFAS analytical tools to further understand the roles of PFAA precursors in a conceptual site model. To continue this discussion, connect with one of our experts below.