The analysis of PFAS by EPA 1633A and ASTM D8421 is part of the U.S. EPA’s Methods Update Rule (MUR) Rule 22. The action will promulgate EPA into 40 CFR Part 136. Also part of this action, PFAS method ASTM D8421 is proposed to be codified. 

EPA 1633A, a collaborative method between the EPA and Department Defense, is a PFAS method capable of analyzing 40 compounds. EPA 1633A is an LC-MS/MS analytical method that can be used to analyze wastewater, surface water, groundwater, soil, sediment, fish tissue, biosolids, and leachate sample matrices. As part of the action, ASTM D8421 will be codified to analyze the same and even more PFAS compounds than EPA 1633A.

The action, signed on December 6, 2024, also included two other analytical methods. In addition to EPA 1633A (PFAS), MUR 22 included EPA 1621 (Adsorbable Organic Fluorine) and EPA 1628 (PCB Congeners). Methods in 40 CFR Part 136 are used to characterize effluents for National Pollutant Discharge Elimination System (NPDES) permit applications, to determine compliance with NPDES permit limits and for other Clean Water Act monitoring requirements.

Merit Laboratories is a leading national PFAS environmental laboratory, analyzing drinking water, soil, wastewater, groundwater, and other sample matrices, including biosolids and sludge. Analytical methods performed by Merit for PFAS include drinking water by EPA 533, EPA 537.1, and EPA 537 rev. 1.1, soil and biosolids by ASTM D7968-17 with Isotopic Dilution, and wastewater, groundwater, and surface water by ASTM D8421 and ASTM D7979-19 with Isotopic Dilution and development of the new EPA 1633A method.