PFAS fingerprinting and the case for source control

Controlling upstream sources, the initial producers or users of toxic PFAS compounds like PFOA and PFOS, has become a bigger priority than ever before. In EPA's PFAS Strategic Roadmap, the agency lays out several plans for source control, like leveraging permitting to reduce discharges and requiring pretreat­ment in certain cases. 

Wastewater experts, like CDM Smith envi­ron­men­tal engineer Eric Spargimino, warn that treating for PFAS at the point of discovery (i.e., drinking water sources, wastewater, landfills, etc.) is not an adequate solution and will place an impossible burden on utilities downstream of where the cont­a­m­i­na­tion originated.

But before we can stop the flow of PFAS, we have to connect the dots.

Finger­print­ing can give us clues to where utilities should focus their PFAS source control efforts.

Chris Gurr, PFAS Remedial Inves­ti­ga­tion Discipline Leader

During the past several years, state and federal sampling directives have led to a boom in collecting PFAS data at water and wastewater utilities and within the environment and creating large databases that can be publicly accessed. Under the right lens, environmental scientists are counting on this new data to show not just where PFAS exist but also the points at which they originate.  

Fingerprinting

Forensic analysis relies on using the variability in PFAS composition (12,000 PFAS and counting) of different products (e.g., AFFF-foams used for fire­fight­ing), with different PFAS products often having unique chemical signatures.  Utilities such as sewers receive discharges from a variety of sources—residential, industrial, commercial—containing multiple types and concen­tra­tions of PFAS products. Therefore, tracing sources of specific PFAS known to be toxic, like PFOA and PFOS, is difficult and many forensic tools are being developed to interpret the new sampling data flooding to online PFAS trackers.

“Just one sample for PFAS can show a large number of detections of individual analytes, depending on the analytical method used," says Chris Gurr, PFAS remedial inves­ti­ga­tion discipline leader at CDM Smith. "We know that different sources of PFAS have different compo­si­tions of PFAS."  

California’s GeoTracker receives thousands of private and public sector analytical and field data from sites that impact, or have the potential to impact, water quality in California. With the help of a statewide sampling directive, California Water Boards now operates a special GeoTracker for PFAS. The Minnesota Department of Health has published an Interactive Dashboard for PFAS Testing in Drinking Water and Maine’s Department of Envi­ron­men­tal Protection has the Maine PFAS Mapper.

Tools like these are indis­pens­able for PFAS forensic inves­ti­ga­tors, providing envi­ron­men­tal engineers and scientists the data to find rela­tion­ships and indicators of specific PFAS sources.  And that is a big step forward toward identifying, and ultimately, controlling sources of PFAS releasing these chemicals into our utilities and environment. "We’re working now to tease out these compo­si­tions as unique finger­prints for a source – and then track those finger­prints downstream, either into the sewer network or in surface water or groundwater resources," says Gurr. "Finger­print­ing can give us clues to where utilities should focus their PFAS source control efforts.”