US DoD Update on PFAS Methods

The annual DoD EMDQ Workshop, usually a source of great information and networking, was cancelled this year.To cover updates that would have been discussed at the workshop, the DoD team hosted an informative webinar on multiple topics. Highlighted below are some PFAS methods updates from Janice Willey’s May 19 presentation.

The PFAS Isotope Dilution Method

SGS AXYS is currently performing the single-lab validation for a universal isotope dilution method to measure PFAS in groundwater, surface water, wastewater, leachate, soil, sediment, biosolid, and tissue. This method is based on SGS AXYS MLA-110, which is already validated and accredited under DoD QSM 5.3 for 33 PFAS. The webinar announced the proposed list of 40 PFAS to cover all EPA 537.1, EPA 533 targets, and several additional precursors. The work is funded by SERDP/ESTCP.

Family Targets
Perfluoroalkyl carboxylates C4-C14
Perfluoroalkyl sulfonates C4-C10, C12
Fluorotelomer sulfonates 4:2, 6:2 and 8:2 FTS
Fluorotelomer carboxylates 3:3, 5:3 and 7:3 FTCA
Perfluorooctane sulfonamides (P)FOSA, MeFOSA, EtFOSA, MeFOSE, EtFOSE, MeFOSAA, EtFOSAA
Ether carboxylates and sulfonates HFPO-DA, ADONA, 9Cl-PF3ONS, 11Cl-PF3OUdS, NFDHA, PFMBA,PFEESA and PFMPA

Per the update, the single lab validation at SGS AXYS is currently in progress. It is an extensive effort that includes initial demonstrations of capabilities, holding time studies, and analysis of three representative samples of each matrix type, unspiked and spiked at three different concentrations. The single-laboratory validation data and method will be considered initially for publication as a draft 1600 series method. Once the multi-lab validation by seven DoD-accredited laboratories and three US state laboratories is complete, changes from the multi-lab validation will be incorporated into the method, and the EPA Office of Land and Emergency Management (OLEM) will consider this method for publication in the SW-846 methods register.

The AFFF and AR-AFFF PFAS Residuals Method

In 2018-2019, SGS AXYS validated a sensitive and accurate method in collaboration with the firefighting foam coalition (FFFC) to measure PFOS, PFOA and 31 other PFAS in AFFF, AR-AFFF foams. The method achieved reporting limits as low as 10 ppb for multiple targets including PFOS and PFOA, much lower than what had been available previously. The method has since been tested at SGS AXYS in other foam types including fluorine-free foams and class A foams. The update announced that all data from the multi-lab validation had been received and was undergoing validation. Two methods will arise from this effort:

  1. A PFOS and PFOA only method to be released in the next 2-3 months with the next MIL-SPEC update
  2. An extended method including all analytes that passed the multi-laboratory validation

Other method initiatives in progress

  1. Total Organic Fluorine (TOF) by combustion ion chromatography (CIC) in firefighting agents to certify foams as fluorine-free to a 1 ppb level by 01-Oct-2023
  2. Air methods for individual PFAS and total PFAS by TOF-CIC, non-target analysis, and sampling protocols in ambient air and stack emissions

Look for these webinars to be posted or linked at the DENIX website.