“The chemistry and analysis of PFAS is unique and challenging, and there is currently no consensus best method for all environmental matrices. The USEPA published Method 537 in 2008 with an update in 2018. This method is applied to 18 PFAS compounds in drinking water matrices only. As of November 2019 EPA published an additional drinking water method, 533. This method was developed to target short chain PFAS compounds and utilizes different analytical techniques than method 537.1. There are similarities and disparities between the two drinking water methods.
Several other methods have been published for PFAS in non-potable and solid matrices including ISO Method 25101, ASTM D7979 and D7968. EPA is in the process of validating a number of methods with various analytical techniques for different matrices; none of which have been published yet. All of these method references address varying target analytes. The Department of Defense (DoD) has compiled quality assurance criteria for PFAS testing under Table B-15 of the Quality Systems Manual (QSM), criteria which has been adopted by a number of States. In order to meet client needs, environmental laboratories have adopted Method 537 and developed significant modifications to address non-potable water and solid matrices. In general, the broader modifications applied are similar between labs, but the opportunity exists for labs to make unique and unqualified modifications. The inconsistent adoption of these modifications yields opportunity for data variability over time and between labs.
This soup of non-validated methods and analytical approaches has left stakeholders with the challenging job of navigating their options and making the right choice for their project objectives. This presentation aims to provide clarity through a comparison of methods and what they are applicable to. An update on what is currently available in terms of published methods versus methods under development will be provided as well.
We hope you will walk away from this presentation with clarity regarding the methods conundrum and a higher comfort level around selecting the right method and protocols for your project objectives.”