Finalizing PFAS Detection Methods, EPA Moves Closer to Locating and Limiting Further PFAS Releases and Requiring Their Cleanup


EPA’s plans to investigate – and eventually establish limits on and liability for – PFAS in wastewater discharges and biosolids crossed a significant milestone on January 31, 2024, with the completion of two new analytical methods to detect these ubiquitous contaminants. The most significant of the two is Method 1633, which provides a standardized quantitative method for laboratories to detect 40 different PFAS compounds, at very low levels, in wastewater, surface water, groundwater, soil, biosolids, sediment, landfill leachate, and fish tissue. Method 1621 is a low-cost screening method for the presence of fluorine-containing organic compounds, which could lead to use of the more sensitive Method 1633 to further characterize any PFAS in the sample. EPA’s public statements provide no timeline for seeking approval of these methods for PFAS monitoring of wastewater discharges as part of 40 C.F.R. Part 136, but a Method Update Rule is likely to be proposed before the end of the year.

EPA has big plans for the PFAS data that these two new methods will generate.

Co-developed by EPA and the Department of Defense, the highly sensitive Method 1633 relies on cutting-edge analytical technologies (LC-MS/MS plus isotopically labeled standards) to quantify these 40 PFAS at levels as low as 1 part per trillion (ppt). Although EPA cannot require NPDES permittees to monitor PFAS in wastewater discharges until Method 1633 is incorporated into 40 C.F.R. Part 136, a Method Update Rule is expected to be promulgated quickly. Moreover, because many states had been reluctant to follow EPA’s recommendation to include PFAS testing in NPDES and pretreatment permits until Method 1633 was finalized, some states might begin to include PFAS monitoring in NPDES permits.

The second method EPA announced as being final is Method 1621, a less costly and less sensitive screening method for detecting fluorine-containing organic compounds down to 1.5 parts per billion (ppb). Method 1621 is a standardized, non-specific, Adsorbable Organic Fluorine (AOF) method that cannot distinguish one fluorine-containing organic compounds from another. It is capable of detecting thousands of members of the PFAS chemical family at a much lower cost than the 40 PFAS capable of being detected by Method 1633. However, fluorine-containing pharmaceuticals and pesticides, if present in the sample, could overstate the presumed “total PFAS” concentrations. Thus, Method 1621 will be used as an inexpensive screening method for detecting fluorine-containing organic compounds in a sample that could be followed by a more sensitive, PFAS-specific quantitative analytical method (such as Method 1633).

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National Law Review, Volumess XIV, Number 40