Investigating Occurrence and Co-occurrence of Emerging Ultrashort Chain PFAS Alongside Legacy PFAS in Potable Water

Per- and Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by Y. Li, J. Whitaker, B. Shretha
Eurofins Drinking Water and Wastewater Central, LLC, 110 South Hill Street, South Bend, Indiana, 46617, United States


Contact Information: [email protected]; 574-472-5562

ABSTRACT

There is a rising concern regarding ultrashort chain PFAS due to their abundant presence in the environment, potable water, and human bodies as well, particularly highly persistent and TFA, regarding its chronic human exposure and potential reproductive and developmental effects. Published data and unpublished results from Eurofins indicate that TFA is much more widespread and at 100 to 1000-fold higher concentrations than the legacy PFAS in potable water. Regulatory actions for individual TFA are also a current topic. Because of the high acidity, solubility. and mobility, ultrashort chain PFAS also pose a huge challenge to common PFAS treatment techniques such as GAC and ion exchange resins.

With the completion of the UCMR5 monitoring program, we now have a good sense of the occurrence of legacy short and long chain (C4-C14) PFAS in drinking water, with approximately 66% of PWSs having more than one PFAS detected and over 8% of PWSs having PFOS and/or PFOA exceeding the federal MCL of 4.0 ng/L. The U.S. regulatory framework for PFAS continues to be muddied as a result of EPA recommendations and judicial decisions, but regardless, many utilities will need to implement treatment. The EU recently adopted drinking water regulations for a sum of 20 PFAS compounds, going beyond the U.S. but with a higher limit of 0.1 µg/L. The EU directive also included total PFAS limit of 0.5 µg/L excluding trifluoroacetic acid (TFA). It is worth noting that the industrial applications of ultrashort chain PFAS are generally different from those of legacy PFAS. Therefore, it is significant to investigate the co-occurrence of ultrashort chain PFAS along with legacy PFAS.

This presentation will take advantage of Eurofins extensive PFAS experience to provide the attendees two objectives. First, it will describe two rapid, sensitive, and cost-effective analytical methods for ultrashort chain and legacy PFAS analyses. The direct aqueous injection LC/MS/MS method is applicable for those ultrashort chain PFAS. The solvent dilution LC/MS/MS is applicable for legacy PFAS comparable with EPA 1633 list. Secondly, it will present the occurrence and co-occurrence data of these PFAS resulting from hundreds of municipal tap water and bottled water samples across the states. The data should be significant for various parties to understand emerging ultrashort chain PFAS contamination alongside legacy PFAS, designing a prioritized, cost-effective PFAS monitoring and treatment strategy that accounts for ultrashort chain PFAS, co-occurring legacy PFAS and other contaminants, and long-term operational considerations.