PFAS Occurrence: What We Have Learned from UCMR5

Drinking Water
Oral Presentation

Prepared by Y. Li
Eurofins Eaton Analytical, LLC, 110 South Hill Street, South Bend, IN, 46617, United States


Contact Information: [email protected]; 574-707-5026

ABSTRACT

In the United States, approximately 22 states have had different kinds of drinking water regulations for 11 per- and polyfluoroalkyl substances (PFAS). Some regulations are more stringent than the others. In June of 2022, the Environmental Protection Agency (EPA) also published the final health advisory levels for 10 ng/L of HFPO-DA and 2,000 ng/L of PFBS, and the interim health advisory levels for 0.004 ng/L of PFOA and 0.02 ng/L of PFOS. To support EPA’s future regulatory determinations and, as appropriate, assist in the development of national primary drinking water regulations (NPDWRs), the fifth Unregulated Contaminant Monitoring Rule (UCMR5) has started to monitor 29 PFAS plus lithium. EPA Methods 533 and 537.1 are used to analyzed the PFAS. One of the four approved methods (EPA Method 200.7, SM 3120 B, SM 3120 B-99, and ASTM D1976-20) is used for lithium. Compared with the first national drinking water assessment monitoring on six high priority PFAS through UCMR3 during 2012‒2016, UCMR5 monitors more PFAS, implements much lower minimum reporting levels (MRLs), and includes more participating public water systems (PWS). Approximately 10,310 PWS and 70,000 samples for each of the methods will be monitored in UCMR5. Compared with the MRLs of 10-90 ng/L in UCMR3, UCMR5 includes the same six high priority PFAS but at much lower MRLs of 3-4 ng/L. In addition, UCMR5 also includes some other commonly-detected PFAS in drinking water, such as PFBA, PFPeA, PFHxA, PFPeS, PFHpS, and 6:2 FTS with MRLs of 3-5 ng/L. Therefore, we can anticipate that more samples and PWS will be detected positive for PFAS in UCMR5.

To date, EPA has published 15% of the total UCMR5 data that EPA expects to receive over the entire monitoring cycle. 18 PFAS have detections in approximately 19% of the samples. This work will provide the latest UCMR5 outcomes through data mining of the National Contaminant Occurrence Database (NCOD). The contaminant occurrence at both the national and state levels will be included. This presentation will also describe various challenges experienced in our laboratories and the solutions implemented to resolve those issues. It is our expectation that this presentation will be helpful in implementing UCMR5, understanding the wide spread occurrence of PFAS contamination in drinking water supplies, planning and executing appropriate PFAS control and remediation actions, and establishing future drinking water PFAS regulations.