Putting the pieces together for PFASs source identification
As regulations on per- and polyfluoroalkyl substances (PFASs) continue to expand, the costs of investigation, management, and remediation remain substantial, so identifying sources and allocating responsibility have become critical.
PFASs source attribution is challenging due to the immense variety of PFASs, their widespread use across industries and products, and the natural transformation of many precursor compounds into more commonly detected and regulated PFASs.
CDM Smith’s extensive expertise in PFASs Forensics provides scientifically defensible PFAS source attribution and liability management solutions by developing multiple lines of converging evidence, enabling informed decisions regarding risk reduction, and potential cost recovery
CDM Smith assists with:
• Identifying the source of detected PFASs
• Differentiating detections from ambient PFASs
• Advanced chemical analytical support
o High resolution mass spectrometry (HRMS) analyses
o Total Oxidizable Precursor (TOP) assay
o 19F Nuclear Magnetic Resonance (NMR)
o Stable Isotope Analysis
• Identifying products containing specific PFASs via databases of historic industrial applications
CDM Smith’s Forensics Team approaches these challenges through a structured approach that integrates multiple analytical chemistry techniques while balancing costs with project objectives. We examine site history, potential uses and products containing PFASs, ambient levels and an understanding of fate, transport, and transformation of PFASs. The outcomes are robust and defensible conclusions regarding sources of PFASs.
Uses and Manufacturing
PFASs were first synthesized in 1890 and have been used and manufactured in bulk commercial products since the early 1930s. Understanding how PFASs were manufactured and used over this time provides critical context for source identification. By linking environmental detections of PFASs to specific products, industrial processes and historical site activities, we help derive lines evidence supporting source identification. When applied early, this knowledge can help strategically focus the breadth of chemical analytical tools applied, often reducing the scope.
Fate and Transport
PFASs have a wide array of physical and chemical properties which impact how they move across a site to impact groundwater, surface waters, soils, sediments etc. Understanding how PFASs migrate once released is critical to identifying and differentiating potential sources. We evaluate PFASs properties taking physical and chemical processes that influence their distribution at a site to determine whether observed impacts are consistent with potential source locations and release histories. Additionally, understanding PFASs fate and transport using more advanced chemical analytical tools can also help distinguish localized source-related impacts from PFASs detections which may represent background.
By integrating hydrogeology, site conditions, and PFAS-specific transport behavior, we develop conceptual site models that support defensible source attribution and contribute to our multiple lines of evidence-based approach. This understanding helps focus investigations on the most likely source areas and migration pathways, potentially reducing unnecessary sampling and lowering overall investigation costs.
Transformational Pathways
The vast majority of PFASs are amenable to natural environmentally induced transformations. Understanding these transformation pathways provides valuable insight into historical releases, source materials, and the processes that may have influenced the ‘weathered’ PFASs composition observed today. By integrating knowledge of PFASs chemistry, environmental conditions, and transformation product relationships, we strengthen the lines of evidence supporting defensible source identification and attribution. In addition, understanding how PFASs transform can provide insight into the potential for ongoing generation of regulated PFASs, predicting future transport behavior, exposure risks, and long-term liabilities. This understanding can inform sampling and analytical efforts to develop robust CSMs.
Applicability of Chemical Analyses
More comprehensive detection of PFASs can be key to a forensic strategy, with single chemical analytical method able to fully characterize and quantify PFASs. Understanding the strengths and limitations of available chemcial analytical methods is critical to developing accurate and defensible forensic investigations. To derive robust lines of evidence supporting source identification and attribution, the appropriate analytical tools must be applied. We evaluate how factors such as qualitative and quantitative analyses using a range of chemical analytical tools, sample preparation, matrix effects, and detection limits influence the detection of PFASs and impacts data interpretation. By strategically applying analytical tools such as targeted analyses, bulk organofluorine detection methods and high-resolution mass spectrometry in a staged, iterative manner, we tailor analytical programs to specific project objectives. The aim is to maximize forensic value to match specific objectives, ensuring the collection of defensible data to support robust lines of evidence supporting source identification.