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IDEM Releases PFAS Data from Public Water Systems: Impacts and Implications

Per- and poly-fluoroalkyl substances (PFAS) have been a topic of increasing interest in recent years and are the target of both federal and state investigations and regulations. These manufactured chemicals are found in a wide range of consumer products, from non-stick cookware to water-repellent clothing, and even in firefighting foams.

Because of their persistence in the environment and potential for long-term health and environmental risks, federal and state regulators are taking targeted action to research, restrict, and ultimately establish regulatory action for remediating PFAS.

The Indiana Department of Environmental Management (IDEM) is taking its own multifaceted approach, including monitoring, risk assessment, public awareness, and preparedness for regulatory action—to address the complex issue of PFAS contamination in Indiana. These are the first steps toward setting hard limits for two of the most widely used and common PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), in water systems.

As part of its comprehensive statewide monitoring program, IDEM refers to the recently-updated interim Health Advisory Levels (HAL) for PFOA and PFOS, established by the Environmental Protection Agency (EPA).

  • Interim updated HAL for PFOA = 0.004 parts per trillion (ppt)
  • Interim updated HAL for PFOS = 0.02 ppt

While the HAL is not a legally enforceable federal standard, it does serve as a safety advisory and will help the EPA develop an enforceable Maximum Contaminant Level (MCL) standard, which is currently proposed at 4 ppt for both PFOA and PFOS.

Driven in part by the EPA’s Unregulated Contaminant Monitoring Rule (UCMR), IDEM began conducting its first of three testing phases in March 2021. In Phase 1, IDEM began examining specific public water systems (PWS) across the state that serve a mid-size population of between 3,300 and 10,000. In Phase 2, testing moved to PWS serving a small population of fewer than 3,300, and in Phase 3, testing moved to PWS serving a larger population of more than 10,000.

The final phase was completed in August 2023 and the results were reported October 3, 2023.

In the comprehensive analysis of test results across all three phases, spanning 477 PWS in Indiana, the findings revealed the following:

  • 77 PWS (16%) contained detectable levels of PFAS.
  • 26 PWS (5.5%) exceeded one or both HAL, as referenced.
  • 10 PWS (2.1%) exceeded one or both proposed MCL.

Those 10 PWS span nine counties, including:

  • Clark (Phase 1 – Indiana American Water, Charlestown)
  • Gibson (Phase 1 – Gibson Water, Inc.)
  • Harrison (Phase 1 – Palmyra Water Works; Phase 3 – Ramsey Water Company, Inc.)
  • Posey (Phase 1 – Mount Vernon Water Works)
  • Vigo (Phase 1 – West Terre Haute Water)
  • Warrick (Phase 1 – Tennyson Water Utility)
  • Sullivan (Phase 2 – Indiana American Water, Farmersburg)
  • Bartholomew (Phase 3 – Columbus Municipal Utility)
  • Jackson (Phase 3 – Jackson County Water Utility)

IDEM has published results from each of the testing phases to spread more public awareness regarding PFAS. IDEM’s efforts, similar to the EPA HAL, are considered non-rule policies, which means they serve as guidelines. And so, although 2.1% of the test sites sampled exceed the EPA’s proposed MCL and even more exceed the HAL, all the results are presented merely to provide a framework for IDEM’s approach to monitoring, assessing, and regulating PFAS chemicals in the future. Stay tuned for when the move toward regulation occurs.