70 analyte PFAS test method highlights need for expanded testing of PFAS in drinking water
Katherine E Pelch1, Taryn McKnight2, Anna Reade1
1Natural Resources Defense Council, 111 Sutter St. Floor 20, San Francisco, CA 94104, USA.
Expanded testing revealed per- and polyfluoroalkyl substances (PFAS) in most drinking water samples, with many exceeding proposed limits. Current regulations may underreport PFAS contamination, highlighting the need for broader testing and ultrashort chain PFAS investigation.
Area of Science:
- Environmental Chemistry
- Public Health
- Analytical Chemistry
Background:
- Per- and polyfluoroalkyl substances (PFAS) are widespread contaminants in drinking water.
- Existing testing methods may not capture the full spectrum of PFAS, including precursor compounds and ultrashort chain variants.
- Community involvement is crucial for understanding localized environmental exposures.
Purpose of the Study:
- To assess the utility of expanded PFAS testing in drinking water using a targeted analysis of 70 compounds and the Total Oxidizable Precursor (TOP) Assay.
- To compare current findings with upcoming regulatory requirements, specifically the Unregulated Contaminant Monitoring Rule (UCMR5).
- To identify gaps in current PFAS monitoring and inform regulatory and scientific communities.
Main Methods:
- Community-led pilot study involving analysis of 44 drinking water samples from 16 states.
- Targeted analysis for 70 PFAS compounds.
- Application of the Total Oxidizable Precursor (TOP) Assay.
- Data filtering to model UCMR5 reporting requirements.
Main Results:
- PFAS were detected in 30 out of 44 samples; 15 exceeded proposed US EPA Maximum Contaminant Levels.
- Twenty-six unique PFAS were identified, including 12 not covered by EPA Methods 537.1 or 533.
- PFPrA (an ultrashort chain PFAS) was frequently detected and often present at the highest concentration.
- All 30 positive samples contained PFAS not captured by UCMR5 modeling, indicating potential underreporting by the rule.
- The utility of the TOP Assay for drinking water monitoring was inconclusive.
Conclusions:
- The upcoming UCMR5 may underreport the true extent of PFAS contamination in drinking water due to limited analyte coverage and higher reporting limits.
- There is a critical need for expanded targeted PFAS analysis and the development of sensitive, broad-spectrum PFAS detection methods.
- Further research into ultrashort chain PFAS, such as PFPrA, is essential for comprehensive environmental monitoring and public health protection.
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