What we're watching.

Watch your PFAS analyte list.

Many PFAS that replaced PFOS and PFOA can undergo biotransformation in the environment, potentially regenerating the very compounds they were meant to replace. These precursor PFAS may not be captured under all analyte lists or methods used, which can lead to a significant underestimation of future regulated PFAS concentrations and the potential extent of liabilities.

Soil PFAS leaching assessments are not all created equal.

Many PFAS are retained in the vadose zone at air-water interfaces in residual soil moisture, and infiltrating water doesn't uniformly travel through the vadose zone to groundwater. The most representative leaching measurements come from intact soil cores. Other methods may introduce significant uncertainty and high bias, potentially overestimating the extent of PFAS threats to groundwater.

Background PFAS is everywhere and it matters.

Anthropogenic PFAS background detections continue to be documented across the US and globally. The United States Air Force is planning background studies at all sites requiring a remedial investigation. PFAS has been found in rainwater (with higher concentrations in urban areas), and a recent New York rural soil background study (December 2025) detected PFOS in 97 percent of samples and PFOA in 76.5 percent, with proposed background threshold values to inform future screening levels and cleanup objectives.

PFAS signatures at the same source can look different at different locations.

Precursor transformation and varying retardation rates mean two sampling locations with the same origin may look significantly different. This has important implications for source attribution in litigation and regulatory contexts.

PFAS management is a "bizarro world" compared to other contaminants.

A phrase coined by Chuck Newell that resonated with us. Biodegradation, typically a remediation goal, is now a potential liability, as precursor breakdown produces more mobile, potentially regulated terminal PFAS. Meanwhile, matrix diffusion into clays and silts, typically a problem, may now be beneficial. There are currently no large scale viable in-situ destruction alternatives for regulated PFAS, which fundamentally reshapes remediation strategy.

PFAS field screening is rapidly commercializing.

Twenty groups have been identified that are commercializing or intending to commercialize rapid PFAS sensing technology. FREDSense is currently the only group offering broadly commercial kits, with a detection limit of 1,000 ppt. Emerging competitors are reporting potential limits of detection as low as 100, 10, and even 2 ppt, a development worth watching closely.

PFAS is potentially present in the beverage industry.

A PFAS audit process for beverage facilities identified multiple entry points: source water, fluorinated packaging (now being phased out), carbonation processes, and AFFF fire suppression systems. A 2025 study found PFAS in 11 of 19 brewery products tested.

• Geology creates the fabric through which water and contaminants move. It always matters.
• No single factor controls PFAS fate and transport; molecular properties of the PFAS and soil characteristics play the largest roles. Fate and transport can also be modified by conditions such as the presence of NAPL, co-contaminants, and redox conditions.
• Different PFAS compounds carry very different risk profiles, with ongoing professional debate around appropriate values for unregulated compounds.
• PFOA and PFOS are now CERCLA Hazardous Substances (May 2024), creating retroactive strict liability for historical releases. The Trump EPA announced in September 2025 it will retain and defend this designation, though litigation in the D.C. Circuit remains pending. CERCLA's broad liability scheme extends to current landowners, water utilities, and passive receivers of PFAS-containing materials such as biosolids.
• Detection of PFAS does not equal risk. Risk equals Toxicity multiplied by Exposure. Presence in environmental samples does not establish a health risk without a proper toxicity and exposure assessment.
• Injected colloidal activated carbon barriers continue to show performance for reducing PFAS mass flux in situ.
• EPA announced intent to rescind the Hazard Index drinking water regulation for PFAS mixtures (May 14, 2025).
• EPA intends to update annual PFAS Destruction and Disposal Guidance to reflect the rapid evolution of treatment technologies.