Per- and Polyfluoroalkyl Substances (PFAS)
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Environmental Health Division
PFAS and Health
Our understanding and ability to detect PFAS in the environment has evolved since the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health (MDH) began investigating them in 2002. Laboratories at that time only identified two PFAS and could not detect low concentrations. We are now able to measure extremely small amounts (parts per trillion in water) of several PFAS and newer studies suggest that long-term exposure to PFAS in this range might affect the most vulnerable members of the population. MDH continues to monitor the scientific research about PFAS and we will adjust our health advice as needed.
PFAS are present in people and animals all over the world. They are found in the environment (air, water, soil, etc.), some food products, and consumer products. People can be exposed to PFAS through the following:
- Drinking contaminated municipal water or private well water
- Eating fish caught from water contaminated by PFAS (PFOS, in particular)
- Accidentally swallowing contaminated soil or dust from indoor or outdoor places
- Eating food grown or raised near places where PFAS were used, manufactured or disposed of
- Eating food packaged in material that contains PFAS
- Using some consumer products treated with or containing PFAS such as stain resistant carpeting, floor waxes, water repellent clothing and personal care products including cosmetics, dental floss, antifog cleaners for glasses, etc.
- Swimming or recreating in contaminated lakes or rivers
More information can be found at PFAS chemical exposure | ATSDR (cdc.gov).
There are many different PFAS, and each may impact health differently. Most studies about their effects on human and animal health have been done on two PFAS chemicals, PFOA and PFOS.
The most consistently observed and strongest evidence for harmful impacts on human health is for immune suppression (such as decreased vaccination response), changes in liver function (such as higher cholesterol, elevated liver enzymes), and lower birth weight. In addition, PFOA has also been associated with kidney cancer. There is limited evidence for additional health effects from different PFAS, including: nonalcoholic liver disease and dyslipidemia, preeclampsia and pregnancy-related hypertension, and hypothyroidism and increased thyroid disease. Other factors such as diet and genetics can also cause some of these health outcomes. Determining whether PFAS chemicals cause health effects in humans and at what levels is an active area of research and we hope to know more in the future.
A limited number of PFAS chemicals have been studied in laboratory animals. These studies show strong evidence that high exposures to PFAS can cause harmful health effects in animals both early in life and as animals get older. Studies have shown some effects such as changes in development, liver and thyroid function, immune response, and increased liver and kidney weight as well as cellular changes. Increased tumors were also observed in certain organs in animals exposed to very high doses of PFOA.
While we believe the immediate health risks for most people exposed to PFAS are low, the latest information indicates that fetuses and infants are more vulnerable. Long term exposure to PFAS such as PFOA, PFOS, and PFHxS leads to a buildup of these chemicals in the body. In women of child-bearing age who experience long term exposure, the buildup of these chemicals can be passed on to the fetus and breastfed babies. Breastfeeding provides many health benefits for mothers and babies. MDH recommends that women currently breastfeeding, and pregnant women who plan to breastfeed, continue to do so. MDH recommends that women who plan to get pregnant follow the recommendations for reducing exposures provided in the “How to reduce exposures” section below.
For more information about breastfeeding, see PFAS and Breastfeeding | ATSDR (cdc.gov).
Consumption of infant formula mixed with water containing PFAS can result in higher exposure to PFAS because babies drink more water per body weight than adults. If you are concerned about exposure to PFAS by consumption of infant formula and would like to lower your baby’s exposure to PFAS, consider using water that has been filtered to remove PFAS, as your water source.
Because PFAS are so widely found in the environment, eliminating all exposure to PFAS is unlikely; however, you can take the following steps to reduce your exposure.
Information about PFAS in public water systems in Minnesota is available at the MDH webpage - Interactive Dashboard for PFAS Testing in Drinking Water. If you live where sources for drinking water are contaminated with PFAS:
- If you use a private well for your drinking water, have your water tested or talk with your local public works department to determine if your household water is also contaminated with PFAS. See Per- and Polyfluoroalkyl Substances (PFAS) and Private Wells.
- Water with PFAS levels above health-based guidance is safe for bathing, showering, swimming, washing clothes, and cleaning, but should not be used for drinking or cooking.
- Reverse osmosis and activated carbon treatment systems can reduce the levels of PFAS in drinking water. MDH provides information about inexpensive and easy to use systems that people can install in their home to reduce exposure to PFAS through drinking water on the following webpages:
- Drinking water and using infant formula
- If your drinking water comes from a private well that has not been tested and you are using formula, you may want to prepare it with water that has been filtered to remove PFAS until your water is tested.
- If your drinking water comes from a public water system which is treating drinking water to at or below MDH health-based guidance, tap water can be used to prepare infant formula.
Even if your local water supply does not contain elevated levels of PFAS, you may want to reduce your exposure to PFAS.
- PFOS may be present in the fish people catch and eat. Fish Consumption Guidance for fish caught in areas affected by PFOS is available on the MDH webpage: Fish Consumption Guidance: Waterbody Specific Safe-Eating Guidelines.
- Certain consumer products contain PFAS. If you are concerned about exposure to PFAS, consider limiting use of items that contain PFAS. Note that not all products in these categories contain PFAS and manufacturers are not required to disclose the use of PFAS in their products. Here is a sampling of items that contain PFAS:
- Some grease-resistant paper, fast food containers/wrappers, microwave popcorn bags, pizza boxes, and candy wrappers.
- Nonstick cookware.
- Stain resistant coatings used on carpets, upholstery, and other fabrics.
- Water resistant clothing.
- Some cleaning products.
- Some personal care products (shampoo, dental floss) and cosmetics (nail polish, eye makeup).
- Some paints, varnishes, and sealants.
- Household dust can be a significant source of PFAS exposure, especially for infants and young children. Indoor sources (e.g., consumer products, floor waxes, stain resistant treated upholstery and carpets) contribute most to PFAS in house dust. Keeping floors and other surfaces free of dust can limit this exposure.
- PFAS may be present in lakes and rivers at very low levels. MDH has determined that exposure to PFAS through swimming is not a health concern. PFAS are poorly absorbed through skin and swallowing small amounts of water while swimming will not result in significant exposure. Also, because there is little evaporation of PFAS from water into the air, breathing them in while swimming or bathing is not a health concern.
- Foam on surface water may contain PFAS at much higher levels than the water. Contact with this foam does not pose a risk to human health if skin contact with foam is minor and infrequent. However, MDH recommends:
- People and pets should avoid contact with foam on surface waters.
- Wash skin that has come into contact with PFAS-containing foam with soap and water.
If you have been exposed to perfluoroalkyl and polyfluoroalkyl substances (PFAS) and are concerned about your health, you can talk to your Health Care Provider.
- We don’t know if exposure to PFAS may cause health problems in the future. You can talk to your health care provider and ask if you need to be monitored for symptoms or conditions that may be caused by PFAS exposure in the future.
- Testing Your Blood for PFAS (PDF) - It is possible to get your blood tested for PFAS, but the results have some important limitations. This information sheet will help you understand what blood testing can tell you and whether blood testing is a good choice for you.
MDH is responsible for ensuring safe drinking water for all Minnesotans. Under the Federal Safe Drinking Water Act (SDWA), MDH monitors drinking water quality through regular testing of public water supplies for contaminants and enforces drinking water standards. MDH also works with MPCA to investigate situations where groundwater contaminants may affect public or private wells. PFAS are not regulated under the SDWA, so MDH uses a variety of other tools and works with local water suppliers to reduce health risks.
MDH began sampling community water systems (CWSs) for PFAS in 2006. Much of this sampling has taken place in the East Metro and in areas where aqueous film-forming foam (AFFF) was used, such as airports and military bases. MDH has a long-term goal of sampling all CWSs in Minnesota for PFAS. Under this goal, MDH aims to cover 90% of CWS customers under its PFAS monitoring program. Through the Statewide PFAS Monitoring Project, MDH will test for PFAS compounds in public water systems across the state. MDH is prioritizing sampling in CWSs and noncommunity water systems (NWSs) that are most vulnerable to PFAS contamination to address the highest potential public health risks. MDH will use these results to evaluate whether other systems in similar settings may be vulnerable to PFAS contamination. Depending on the results, MDH may recommend actions to individual Public Water Systems to address potential health risks from PFAS compounds detected in the project - no actions will be required. See PFAS Testing of Public Water Systems for more information.
MDH has developed health-based guidance values to represent levels for several PFAS in drinking water. The guidance values are levels that MDH considers safe for all people to consume, including sensitive populations. The guidance values apply to short time periods as well as a lifetime of exposure. The table below shows the health-based guidance values (in parts per billion, or ppb) and parts per trillion (ppt) for six PFAS that MDH uses to evaluate sample results. Because the guidance values are low, they are often reported in parts per trillion (ppt). One ppb is 1,000 ppt.
More information can be found on the MDH Guidance Values and Standards for Contaminants in Drinking Water webpage.
Table of Health-based Values for PFAS
PFAS Detected in MinnesotaPFAS Specific Information Sheet Available
Drinking Water Guidance Value (ppb)
perfluorobutane sulfonate (PFBS)PFBS and Drinking Water (PDF)
perfluorohexane sulfonate (PFHxS)Toxicological Summary for: perfluorohexane sulfonate (PFHxS) (PDF)
perfluorooctane sulfonate (PFOS)PFOS and Groundwater (PDF)
perfluorobutanoic acid (PFBA)PFBA and Drinking Water (PDF)
perfluorohexanoic acid (PFHxA)Toxicological Summary for: Perfluorohexanoate (PFHxA) (PDF)
perfluorooctanoic acid (PFOA)PFOA and Drinking Water (PDF)
How changing knowledge has impacted drinking water guidance over time
MDH has been working on guidance for PFAS in drinking water since 2002. Knowledge and understanding of PFAS has grown and evolved. Below is a description of how drinking water guidance has adjusted over time.
As of early 2023, PFOA and PFOS are again in the process of being re-evaluated based on newly available information.
See Guidance Values and Standards for Contaminants in Drinking Water for more information about different values and standards MDH uses and develops for different purposes to protect people’s health from contaminants in drinking water.
MDH Guidance Values (ppb) – 2002 to 2022
How health risk is assessed when more than one chemical is present in drinking water
Exposure to multiple contaminants may cause health effects that would not be predicted based on separate exposures to the individual concentrations of each contaminant present. When more than one PFAS is present in drinking water, MDH evaluates the “additive” risk that is created by the presence of multiple contaminants.
A Health Risk Index (HI) calculation is used to evaluate the combined risk from chemicals that have similar health effects. For each chemical a ratio is calculated by comparing the groundwater concentration of the chemical to the exposure duration-specific health-based guidance for that chemical. Chemicals are grouped by health effect and a HI is calculated for each chemical. These HI values are added together. If a total HI calculation results in a value greater than 1, that exceeds the allowable risk level and preventative action is recommended.
- Cancer risks for each chemical in a mixture are added together for a cancer HI
- Non-cancer risks for each chemical are grouped by health effect (liver, kidney, nervous system, etc.) and added together
For more information, visit the MDH webpage: Evaluating Concurrent Exposures to Multiple Chemicals.
MDH develops health-based air guidance values to evaluate potential human health risks from exposures to chemicals in ambient air. An air guidance value is a concentration of a chemical that is likely to pose little or no risk to human health. Air guidance values are developed using public health protective practices that protect susceptible portions of the population (including but not limited to children, pregnant women and their fetuses, individuals compromised by pre-existing diseases, and elderly persons). Air guidance values apply to short time periods as well as a lifetime of exposure.
MDH has not previously derived air guidance values for PFAS. Currently, there is insufficient inhalation data available for PFAS to derive air guidance directly; however, PFAS information via the oral exposure route is more robust. Route-to-route extrapolation was implemented using MDH’s health-based guidance values information for PFAS in drinking water to derive air values.
More information can be found on the MDH Air Guidance Values webpage.
The table below shows the air guidance values (in micrograms per cubic meter, µg/m3) for five PFAS. MDH intends to derive air guidance values for additional PFAS as information becomes available.
Table of Current Air Guidance Values for PFAS
PFAS ChemicalPFAS Specific Air Information Sheet
Air Guidance Value
Perfluorobutanoic acid (PFBA)Air Toxicological Summary for Perfluorobutanoic acid (PDF)
Perfluorohexanesulfonic acid (PFHxS)Air Toxicological Summary for Perfluorohexanesulfonic acid (PDF)
Perfluorohexanoic acid (PFHxA)Air Toxicological Summary for Perfluorohexanoic acid (PDF)
Perfluorooctanoic acid (PFOA)Air Toxicological Summary for Perfluorooctanoic acid (PDF)
Perfluorooctane sulfonic acid (PFOS)Air Toxicological Summary for Perfluorooctane sulfonic acid (PDF)
Perfluorobutane sulfonic acid (PFBS)
Stress at Contaminated Sites: Coping with the stress that environmental contamination can cause (PDF)
Printable Information Sheets
- PFAS in Drinking Water (one-page summary)
- Perfluoroalkyl Substances (PFAS) and Health (PDF)
- Perfluoroalkyl Substances (PFAS) Summary (PDF)
- Reducing Exposures: Perfluoroalkyl Substances (PDF)
- Testing Your Blood for PFAS (PDF)
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