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Per- and Polyfluoroalkyl Substances (PFAS) in drinking water

See frequently asked questions and answers.

This fact sheet answers frequently asked questions about the detection of Per- and Polyfluoroalkyl Substances (PFAS) in drinking water. It includes information about a drinking water guideline for PFAS established by the Massachusetts Department of Environmental Protection (MassDEP) in January 2020.


What are PFAS?

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals manufactured and used in a variety of consumer products and industries throughout the world. Two of these PFAS chemicals, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have been the most extensively produced and studied. They have been used to make carpets, clothing, fabrics for furniture, paper packaging for food, and other materials (e.g., cookware) that are resistant to water, grease or stains. They are also used in aqueous firefighting foam and in a number of industrial processes. Because these chemicals have been used in an array of consumer products, most people have been exposed to them.

Many PFAS are no longer being produced in this country; the largest manufacturer completely stopped PFOA/PFOS production in 2002. PFAS are still being produced in other countries and may be imported into the US in limited quantities. The US Environmental Protection Agency (EPA) and the PFAS industry launched the PFOA Stewardship Program in 2006 to work toward ending the production of PFOA and other PFAS.

While consumer products and food are a large source of exposure for most people, drinking water can be an additional source in the small percentage of communities where these chemicals have contaminated water supplies. Such contamination is typically localized and associated with a specific facility, (e.g. an industrial facility where these chemicals were produced or used to manufacture other products or where firefighting foam was used).

How are PFAS regulated?

There are currently no established state or federal regulatory limits for levels in drinking water. The US EPA set a health advisory level (HA) of 0.070 micrograms per liter (µg/L) for both PFOA and PFOS in May 2016. The US EPA HA is based on a level that is safe to drink for an entire lifetime.

In June 2018 the Massachusetts Department of Environmental Protection (MassDEP) established an Office of Research and Standards Guideline (ORSG) for drinking water of 0.070 µg/L. This ORSG applied to five PFAS, including PFOA, PFOS, perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), and perfluorohepatanoic acid (PFHpA). In January 2020 MassDEP lowered the ORSG to 0.020 µg/L and expanded the guideline to also include perfluorodecanoic acid (PFDA).

MassDEP also recommends compliance with this level for short-term (weeks to months) PFAS exposures during pregnancy and breast-feeding.  This recommendation means that pregnant women, nursing mothers, and infants should not consume water when the level of the six PFAS, individually or added together, is above 0.020 μg/L.

How can PFAS affect my health?

There are many gaps in the current scientific literature, but it is believed that PFAS may affect human health. Most research is based on animal studies and scientists are still unsure of the difference between how animals and humans respond to PFAS. PFAS exposures in these studies have been associated with changes in thyroid, liver, and kidney function, as well changes in hormone levels. PFOA and PFOS have also been shown to cause developmental effects to fetuses during pregnancy and in breastfed infants.

Can PFAS cause cancer?

There is no conclusive evidence that PFAS cause cancer, though several animal studies and legal cases have identified a possible link between them. The EPA reports there is suggestive evidence that PFOA and PFOS can increase the risk of cancer. Both the EPA and the National Toxicology Program are continuing research on the cancer potential of PFAS.

What is my risk if I drank water above the MassDEP Guideline?

Drinking water at a level above MassDEP's guideline does not necessarily mean that health risks are expected. This is because the guideline is based on a level that is safe to drink for an entire lifetime. By convention, a value such as the guideline is used as a “screening” value that is designed to overestimate exposure and ensure that sensitive individuals are protected. For example, the guideline assumes that individuals drink only contaminated water and are also exposed to PFAS from sources beyond drinking water, such as food. Several safety factors are additionally applied to account for the differences between animals and humans and the differences from one human to another human. Under this scenario, a risk would be expected only if an individual continuously drinks only contaminated water at a level significantly higher than the guideline.

What should I do to limit exposure?

PFAS are found at low levels in the environment, consumer products, and food, so it is nearly impossible to eliminate all exposure. If PFAS contamination has been identified in your drinking water, there are several ways to limit your exposure such as drinking and cooking with bottled water, and using pre-mixed baby formula, or bottled water for reconstituting powdered formula. Routine showering and bathing are not significant sources of exposure.

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