PFOA & PFOS Testing: Not Why, But How?


The concern over polyfluoroalkyl substances like PFOA and PFOS is clear—what is less clear is how we will be testing for them.

Currently, there is no fully validated, approved EPA method to detect polyfluoroalkyl substances (PFAS) in non-drinking water matrices at either the State or Federal level, despite recent State guidelines and EPA health advisories. Even in regard to drinking water, things are a bit murky. The U.S. EPA authorized EPA method 537 for select PFAS analysis in drinking water under the third round of the Unregulated Contaminant Monitoring Rule program (UCMR 3). However, the EPA’s drinking water program does not have any requirements for post-UCMR monitoring since PFOA, PFOS, and the other UCMR target analytes are not yet regulated under the Safe Drinking Water Act. Similarly, California has not previously offered accreditation for PFAS, and therefore no laboratory is currently certified by California ELAP to perform the analysis.

This does not mean laboratories are completely without accreditation. For example, Babcock Labs is accredited to perform EPA method 537 in drinking water under its NELAP accreditation through the state of Oregon (ORELAP). Babcock Labs was also one of the limited number of EPA approved laboratories under UCMR 3, and therefore has extensive experience with PFAS determination.

At Babcock Labs’ recent TEAM Event, esteemed guest Christine Sotelo, Chair of CA ELAP, mentioned that ELAP has begun accepting data package submissions for PFOA/PFOS accreditation additions, and the Division of Drinking Water (DDW) has identified EPA method 537 as a validated analytical method for detecting perfluorinated compounds in drinking water. However, ELAP has not yet indicated which other methods will be offered for accreditation under the wastewater and hazardous water fields of accreditation.     

It remains to be seen how California, along with the rest of the country, will handle PFAS/PFOS testing for non-drinking water matrices. What methods will be validated and approved? Currently, there are no regulatory EPA methods for analyzing PFAS in surface water, non-potable groundwater, wastewater, or solids. In response to notifications from the Regional Boards, however, many proactive agencies are requesting “Modified EPA method 537,” despite the fact that the methods modifications have not been validated or systematically assessed for data quality. Laboratories like ours are happy to offer Modified EPA Method 537, but we do have concerns regarding accreditation and regulatory agency expectations.    

To address this, the EPA is currently in the process of developing a SW-846 direct injection method for quantifying 24 PFAS analytes in matrices other than drinking water. A final draft for public review is expected this Fall. The EPA also plans to validate a solids method (isotope dilution) starting this fall using a similar phased approach. Additionally, an analytical method for short-chained PFAS in drinking water is under development and planned for external validation and publication for public review by early 2019.

In summary, while we have gained a better understanding of the potential dangers PFAS—such as PFOS and PFOA—pose to human health and the environment, there remain numerous questions regarding how to best test for them across matrices in a way that will produce data of known and documented quality.