About PFAS

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic organic chemicals that contain fluorine. There are more than 3,000 PFAS. Because many PFAS have useful properties, some of them have been used since the 1940s in products like textiles, paper, cookware, firefighting foams, and electronics. Though U.S. production of some of these chemicals has declined, many are still produced in other countries. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have been among the most used PFAS. The U.S. Environmental Protection Agency (U.S. EPA) has added PFAS chemicals to the Toxics Release Inventory and is also developing rules to regulate exposures of certain PFAS chemicals.

PFAS in the Environment

PFAS are commonly present at fire training and response sites, certain industrial facilities, landfills, wastewater treatment plants, and in biosolids. PFAS persist in the environment, can bioaccumulate, and are often present in people and in wildlife. Due to the large volumes of PFOS and PFOA used in the past, these chemicals are the most frequently detected PFAS.

PFAS Health Effects

Both PFOA and PFOS are commonly found in the environment. Studies indicate that exposure to PFOA and PFOS above certain levels may result in adverse health effects. See additional resources.

Looking for PFAS

On July 30, 2021, the U.S. EPA published SW-846 preparation and analysis methods 3512 and 8327 for selected PFAS in non-potable water such as, surface water, groundwater, wastewater.  In addition, Method 1633 can be utilized for aqueous matrices which includes wastewater, surface water, groundwater, and landfill leachate, but can also be utilized for soil, sediment, biosolids, and fish and shellfish tissue analyses. These methods are in addition to U.S. EPA’s 537, 537.1, and 533 methods for drinking water. Sampling and analysis methods for PFAS in other environmental media are under development. U.S. EPA has proposed nationwide drinking water monitoring for PFAS at smaller public water systems beginning in 2022.

PFAS Sampling Project for Community Public Water Systems

Since February 2021, IDEM facilitated PFAS monitoring at all Community Public Water Systems (CWS) throughout the state of Indiana (a CWS regularly serves drinking water to at least 25 year-around residents or has at least 15 service connections for residents). Samples were collected at all raw water (i.e. wells and intakes) and finished (after treatment) water points in a CWS’s supply. The purpose of the sampling program is to evaluate the statewide occurrence of PFAS compounds in CWS across the state and determine the efficacy of conventional drinking water treatment for PFAS.

Timeline for Sampling PFAS at Community Water Systems

IDEM’s sampling plan is outlined below and is dependent upon available funding. IDEM first sampled at community systems serving a population of less than 10,000 because most of these smaller systems were not sampled for PFAS during U.S. EPA’s Unregulated Contaminant Monitoring Rule (UCMR) sampling completed in 2014 and 2015. Systems serving a population greater than 10,000 were sampled last since they were sampled as part of U.S. EPA’s UCMR sampling. No verified PFAS detections were found in Indiana during the UCMR sampling event.

IDEM has received an Emerging Contaminants Grant extension to study PFAS in Indiana surface water bodies that are used for drinking water. This will be Phase 4. Phase 4 sampling is expected to begin Spring of 2024.

• Phase 1 Results [XLSX] - Updated May 2023
• Phase 1 Resample Results [XLSX] - Updated June 2023
• Phase 2 Results [XLSX] - Updated January 2024
• Phase 2 Resample Results [XLSX]
• Phase 3 Results [XLSX] - Updated November 2023
• Phase 3 Resample Results [XLSX] - Updated April 2024
• Phase 4 Results [XLSX] - Updated September 2024
• Phase 4 Resample Results [XLSX] - Updated October 2024

PFAS Sampling in Fish Tissue

Fish is a part of a healthy diet when consumed in moderation as it is a source of lean protein and omega-3 fatty acids. However, fish can also contain environmental contaminants at levels high enough to harm human health. In 2017, IDEM started analyzing fish tissue for PFAS from rivers, streams, lakes, reservoirs, and Lake Michigan. PFAS data in fish tissue is used to track trends over time, to understand background concentrations in the state, identify potential sources, and to explore bioaccumulation patterns in fish species. The data is also used to support the IDOH Fish Consumption Guidelines, following the Best Practice for Perfluorooctane Sulfonate (PFOS) document. For more information, visit Health: Environmental Public Health: Fish Consumption Guidelines”.

• Indiana PFAS in Fish Tissue through 2023 [XLSX] - Updated September 2024

U.S. EPA has finalized the nationally recommended aquatic life criteria for PFAS compounds. For more information, please review the published fact sheet below:

• U.S. EPA Fact Sheet: Final Recommended Aquatic Life Criteria and Benchmarks for Select PFAS [PDF] - September 2024

Development of Standards

On April 26, 2024, U.S. EPA published a final National Primary Drinking Water Regulation (NPDWR) to establish legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six PFAS in drinking water. PFOA, PFOS, PFNA, PFHxS, and HPFO-DA (commonly referred to as GenX Chemicals) as individual contaminants, and PFAS mixtures containing at least two or more of PFHxS, PFNA, PFBS, and HFPO-DA using a Hazard Index MCL. U.S. EPA also announced health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS. These levels become final on June 25, 2024.

EPA-provided a fact sheet on how to calculate the Hazard Index for PFNA, PFHxs, PFBS, and GenX Chemical mixtures. Water systems must take action to reduce the levels of these PFAS in drinking water if the level of PFAS in their drinking water exceeds regulatory standards. Regulated public water systems have three years to complete their initial monitoring (by 2027) for these chemicals. Systems must include their results in their Annual Water Quality reports to customers. Systems that detect PFAS above the new standards will have five years (by 2029) to implement solutions that reduce PFAS in their drinking water. Water systems must also notify the public if levels of regulated PFAS exceed these new standards.

Treatment Technologies

• Activated Carbon, Ion Exchange Treatment, High Pressure Membranes (Reverse osmosis and Nanofiltration)
• Some technologies are more effective against longer or shorter chains
• Based on design choices, 100% removal of PFAS compounds can be achieved, but costs and remediation targets may make complete removal impracticable or unnecessary
• None of these technologies destroy the PFAS molecule, so PFAS are essentially being concentrated, and the waste stream will have to be properly disposed of as a hazardous waste.

PFAS Remedies

Currently available remedies for PFAS in water include filtration and chemical treatment. Excavation and disposal, physical barriers, and heat treatment are among effective remedies for PFAS in soils. Other technologies are under development by U.S. EPA, U.S. Department of Defense, private industry, academic research institutions, and others.

Additional IDEM Activities

• Development of Published Levels
  • IDEM has established published levels for 11 PFAS compounds listed in the Risk-Based Closure Guide (R2) published level table. Published levels are concentration levels specific to individual chemicals, land uses, and media (soil, water, indoor air) that IDEM has determined to be protective of human health. Upon U.S. EPA finalization of the above MCLs, they will be incorporated into an updated R2 published level table.
• Partnering with Stakeholders
  • Firefighting Foam: In 2020, Indiana law banned the use of Class B firefighting foam containing intentionally added PFAS, typically known as aqueous film-forming foam (AFFF), for training purposes. (See IC 36-8-10.7) IDEM has partnered with the Indiana Department of Homeland Security and the State Fire Marshal’s Office to collect PFAS-containing firefighting foam from fire departments around the state. The IDHS Division of Fire and Building Safety provides more information on this joint initiative.
  • Military Bases: Since firefighting foam is known to contain these contaminants, military bases have been a concern. Military contractors are now sampling at various military locations around the state to determine the extent of PFAS contaminants. Drinking water has not been found to be impacted by PFAS at these locations.
  • Ohio River: The Ohio River Sanitation Commission (ORSANCO), in partnership with member states, completed an ambient sampling project for PFAS in 2021 to determine background levels of these contaminants in the river. The full report and data results can be viewed and downloaded online at here: Ambient PFAS Levels in the Ohio River - ORSANCO.

Funding Options

The Bipartisan Infrastructure Law provides $9 billion specifically to invest in communities with drinking water impacted by PFAS and other emerging contaminants. This includes $4 billion to the Drinking Water State Revolving Fund (DWSRF) and $5 billion through EPA’s Emerging Contaminants in Small or Disadvantaged Communities Grant Program. States and communities can further leverage an additional nearly $12 billion in the DWSRF dedicated to making drinking water safer, and billions more that the federal government has annually provided to fund DWSRF loans. These funds will help communities make important investments in solutions to remove PFAS from drinking water and are a critical foundation on which to build to address this issue across the nation. More information about the Bipartisan Infrastructure Law and its emerging contaminant funding can be found at https://www.epa.gov/infrastructure.

Initial Sampling Requirements

Within the first three years after the date of final rule promulgation, Community Water Supplies (CWSs) and non-transient non-community water system (NTNCWSs) must complete initial monitoring at all entry points to the distribution system. Based on system size and source water at an entry point, systems must conduct initial monitoring either twice or quarterly during a 12-month period as follows:

To reduce costs for systems, primacy agencies can allow systems to use previously collected monitoring data to satisfy some or all the initial monitoring requirements, if the sampling was conducted using EPA Methods 533 or 537.1 as part of Unregulated Contaminant Monitoring Rule (UCMR) 5, state-level, or other appropriate monitoring campaigns. Therefore, UCMR results, as well as the Voluntary Drinking Water PFAS Project Sampling results, can be used to count towards initial sampling results, if they were collated after 2019.  The systems would have to ensure the proper collection times of the samples they are still required to obtain.

Initial Sampling Requirements Guidance Documents

• PFAS Initial Sampling Requirements Surface Water CWS [PDF]
• PFAS Initial Sampling Requirements Groundwater CWS Serving less than 3,300 Customers [PDF]
• PFAS Initial Sampling Requirements Groundwater CWS Serving 3,300 - 10,000 Customers [PDF]
• PFAS Initial Sampling Requirements Groundwater CWS That Serve Over 10,000 Customers [PDF]

Additional Resources

• IDEM PFAS Sampling Project for Community Public Water Systems [PDF]
• IDEM: Risk-Based Closure Guide (R2) - Published Levels
• Indiana Administrative Code: PFAS Containing Firefighting Foam Use in Training
• IDEM/IDHS Class B PFAS Foam Collection Initiative
• Indiana State Department of Health: Per- and Polyfluoroalkyl Substances (PFAS) in Fish [PDF]
• Agency for Toxic Substances and Disease Registry (ATSDR)
• U.S. Department of Defense
• U.S. Environmental Protection Agency: PFAS
  • PFAS Analytical Methods
  • PFAS Communications Toolkit
  • PFAS Drinking Water Regulation - Final
  • PFAS Strategic Roadmap
• Toxic Release Inventory Additions

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