Perfluoroalkyl substances (PFAS)

PFAS blood levels


PFAS are common chemicals

PFAS, also referred to as perfluorochemicals (PFCs), are chemicals that have been used for many years to make products that resist heat, stains, grease and water. Items that may contain PFAS include furniture, carpets and clothing that are treated to resist stains and repel water, nonstick cookware, fire-fighting foams and fast food packaging. PFAS have also been found in groundwater in Minnesota, including in some communities of the East Metro of Minneapolis-St. Paul.

PFAS are extremely stable and do not breakdown in the environment. Scientists are actively studying whether PFAS cause health problems in people. Researchers have found links between PFAS and some human health outcomes. In some studies, higher levels of PFAS in a person’s body were associated with higher cholesterol, changes to liver function, reduced immune response, thyroid disease, and increased kidney and testicular cancer. More work needs to be done to determine if PFAS or other factors caused the health outcomes.

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.


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

 
Averages shown are geometric means (n = 149). Data source: Minnesota Department of Health and National Health and Nutrition Examination Survey, 2013-2014.
 
Results showed that the efforts to reduce PFAS in drinking water are working to reduce residents’ exposures. 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

 
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

 
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

 
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.

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

MDH also conducted PFAS biomonitoring in Minnesota communities.

 

See also

PFAS Blood testing Information Sheet (PDF)