Are there PFAS in my water? A detailed look into bottled water

Significance of the Topic

This study addresses the occurrence of per- and polyfluoroalkyl substances (PFAS) in bottled water, an emerging concern due to their environmental persistence and potential health impacts. While PFAS contamination in drinking water and foods has been widely examined, bottled water remains a less explored vector. Identifying and quantifying PFAS in different bottle materials and water sources can inform regulatory guidelines and consumer safety measures.

Objectives and Study Overview

The primary goal was to develop a rapid, direct-injection LC-MS/MS method to detect 24 target PFAS compounds and 19 isotopically labeled surrogates in commercially available bottled waters. Key aims included:

• Comparing PFAS levels across seven types of bottled water
• Assessing influence of container materials (virgin and recycled plastic, glass, metal, cardboard)
• Evaluating differences between spring and purified water sources

Methodology and Instrumentation

Sample Preparation:

• Bottled water samples diluted 1:1 with methanol containing 0.1% acetic acid
• Spiked with internal standards, vortexed, then filtered through 0.2 µm syringe filters
• No solid-phase extraction required

Chromatography and Detection:

• Shimadzu Nexera X2 SIL-30AC autosampler coupled to LCMS-8050 triple quadrupole MS
• Restek Raptor C18 analytical column (2.1×150 mm, 2.7 µm) with PFAS delay column to eliminate system background
• Mobile phases: A = 20 mM ammonium acetate in 5% acetonitrile; B = 10 mM ammonium acetate in 95% acetonitrile
• Gradient run over 21 minutes, 0.3 mL/min flow rate, 30 µL injection volume
• Negative electrospray ionization, multiple reaction monitoring transitions optimized for each analyte

Main Results and Discussion

Method Performance:

• Recovery range: 87.6–129.5% for an 80 ppt standard
• Reproducibility: RSD < 10% for most compounds
• Limit of quantitation: 10 ppt

PFAS Occurrence:

• Only PFBA (perfluorobutanoic acid) and 6:2 fluorotelomer sulfonate detected above LOQ
• Plastic bottles consistently showed measurable PFBA and 6:2 FTS
• Bottle made from 50% recycled plastic had the highest total PFAS concentration
• Glass and cardboard containers exhibited no detectable PFAS
• One spring water sample in plastic contained elevated PFBA, suggesting potential source contamination

Benefits and Practical Applications

This direct-injection method offers:

• Minimal sample preparation and rapid throughput
• Compliance with FDA draft method C-010.01 and EPA guidelines
• Capability to screen a broad PFAS panel in diverse water matrices
• Cost-effective approach suitable for routine monitoring in QA/QC and environmental testing laboratories

Future Trends and Applications

Ongoing research may include:

• Expansion to isotopic dilution quantification for enhanced accuracy
• Investigation of additional PFAS classes and emerging analogs
• Large-scale surveys across geographic regions and bottle brands
• Assessment of migration mechanisms from recycled plastics and alternative materials
• Integration of online delay columns and automation for high-throughput labs

Conclusion

The presented LC-MS/MS protocol demonstrates robust sensitivity, precision, and ease of use for PFAS analysis in bottled water. Findings highlight plastic, particularly recycled variants, as a significant PFAS source, whereas glass and cardboard pose minimal risk. Further studies are essential to confirm these trends and inform regulatory standards.

References

• FDA Makes Available Testing Method for PFAS in Foods
• FDA Second Round of PFAS Testing Results for Foods
• Environmental Science and Technology. Polyfluorinated Compounds: Past, Present, and Future
• International Bottled Water Association – Recommended PFAS Levels
• US EPA Basic Information about Per- and Polyfluoroalkyl Substances