Per- and Polyfluoroalkyl substances (PFAS)

PFAS blood levels

About PFAS 

PFAS are a family of human-made chemicals that have been widely used for decades. PFAS are extremely stable and do not breakdown in the environment. PFAS have been found in the groundwater and surface water in Minnesota. Some PFAS can build up and stay in the human body for many years. They can also slowly decline if the exposure stops.

PFAS are commonly used for their water- and grease-resistant properties. People can be exposed 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

Exposures that are expected to be minor include 1) exposure through skin contact because absorption through skin is low and 2) exposure through breathing in fine water droplets is expected to be infrequent, short, and involve small amount.

PFAS are emerging contaminants. Emerging contaminants are contaminants about which we have a new awareness or understanding about how they move in the environment or affect public health. PFAS, like other emerging contaminants, are the focus of active research and study, which means that new information is released frequently. 

Health Risk

Scientists are actively studying PFAS exposures and human health impacts. Numerous studies have shown that higher levels of exposure to PFAS are associated with a wide range of human health effects. These include higher cholesterol, changes to liver function, reduced immune response, thyroid disease, and, in the case of PFOA, increased kidney and testicular cancer. However, more work needs to be done to determine if PFAS, or other factors, caused the effects. Research continues on PFAS to determine effects on birth outcomes, hormone balance, cholesterol levels, immune response, and cancer. There are many different PFAS and each may have varying roles for different effects. 

Read Reducing Exposures: Per- and Polyfluoroalkyl substances (PFAS) (PDF) to learn how to take the steps to reduce your exposure to PFAS.

Biomonitoring shows PFAS levels in the body

Biomonitoring measures the amount of PFAS in a person’s blood. There are no reference levels for "safe" or "unsafe" amounts of PFAS in the body. Most people in the U.S. have PFAS in their body because these chemicals are commonly used. 

There are many different PFAS. The three shown on this page are the most commonly detected in people: perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonate (PFHxS). These three PFAS stay in the body for years.

PFAS blood levels in Minnesota communities

In the East Metro of Minneapolis-St. Paul, some drinking water sources were polluted with PFAS. Filtration systems were installed in 2006 on the Oakdale municipal water system and on many private wells in the area to remove these chemicals. Ongoing work at MDH ensures that water levels are regularly tested and below MDH’s health-based water values.

MDH has conducted biomonitoring in a group of long-term residents of the area since 2008, measuring PFAS blood levels in the same group of people in 2008, 2010 and 2014. These people were exposed to PFAS in drinking water before the filtration systems were installed.The projects have found that levels of PFAS in blood are decreasing in East Metro residents who were exposed to PFAS, and that the efforts to reduce PFAS in drinking water in the area have worked.

To help you understand your PFAS results, see What's My Exposure, a tool created by the PFAS Exchange.

PFAS blood levels in long-term residents of the East Metro

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Averages shown are geometric means (n = 149). Data source: Minnesota Department of Health and National Health and Nutrition Examination Survey, 2013-2014.
 
On average, individual levels of PFOS went down by 45%, PFOA by 59%, and PFHxS by 34% over 6 years.
 
In 2014, MDH conducted biomonitoring in a group of newer residents to the area. These people moved to the East Metro after the 2006 intervention and were not exposed to high PFAS levels in drinking water.
 

PFAS blood levels in new residents of the East Metro

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Averages shown are geometric means (n = 156). Data source: Minnesota Department of Health and National Health and Nutrition Examination Survey, 2013-2014.
 
Results showed that their levels were similar to those seen in the U.S. population and they do not appear to be having unusual exposures.
 

PFAS blood levels in the U.S. population

 
PFAS blood levels are measured in a group of people 12 and older that represent the U.S. population through the National Health and Nutrition Examination Survey (NHANES). These national results can be compared to biomonitoring in Minnesota.

PFAS blood levels in the U.S. population

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Averages shown are geometric means among people 12 years and older. Data source: National Health and Nutrition Examination Survey, 1999-2016.
 

 

Blood levels of PFOS and PFOA have declined in the U.S. population since 1999. The trend over time is less clear for PFHxS. These declines are a result of reductions in the production of certain PFAS during this time period. 3M, formerly the primary manufacturer of PFOS world-wide, stopped producing PFOS in 2002. Efforts are also underway to reduce PFOA production and use.

PFAS blood levels in the U.S. population by sex

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Averages shown are geometric means among people 12 years and older. Data source: National Health and Nutrition Examination Survey, 2015-2016.
 

 

Men in the U.S. have higher blood levels of PFAS than women. This difference has been seen in many scientific studies, including biomonitoring in Minnesota. The difference may be due to the ways PFAS are cleared from the body and differing product use. Women can clear PFAS through menstruation, childbirth and breastfeeding.

What is being done about PFAS in Minnesota?

Since 2002, MDH has worked to protect drinking water for Minnesotans, collaborated with the Minnesota Pollution Control Agency on contaminated site investigations, developed health-based guidance for PFAS in drinking water, provided information for health care providers, and provided fish consumption advice for lakes and rivers tested for PFAS. Updates on the 3M PFAS 2018 settlement can be found with the Minnesota Pollution Control Agency.

The MPCA is also developing a PFAS Blueprint to support a statewide, systematic approach to address PFAS concerns in Minnesota.

For current information about MDH activities and links to other helpful information, visit the MDH Perfluoroalkyl Substances (PFAS) webpage.

See also

PFAS Blood testing Information Sheet (PDF)

 

Last updated: January 2024