Update: Perfluorochemicals and Private Drinking Water Wells in Lake Elmo: Environmental Health: Minnesota Dept. of Health

Hazardous Sites and Substances in Minnesota
Update: Perfluorochemicals and Private Drinking Water Wells in Lake Elmo
July 2006

Note: This is an archived page. Current page is accessible from the links on left.

As you are aware, local and state agencies are continuing to investigate the extent and levels of chemicals in the perfluorochemicals (PFCs) group in the groundwater under western Lake Elmo. The purpose of this update is to let you know about several recent developments.


In 2002 the Minnesota Pollution Control Agency (MPCA) requested that the Minnesota
Department of Health (MDH) develop Health Based Values for two members of the
perfluorochemical group: PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate) because they were used and disposed in Minnesota. A Health Based Value (HBV) is the amount of a chemical in drinking water that MDH scientists consider safe for people to drink daily for a lifetime. The HBV for PFOA is currently 7 parts per billion and the HBV for PFOS is 1 part per billion.

In 2004, the MDH Public Health Laboratory developed a method for detecting PFOA and PFOS and the MDH and the MPCA began testing drinking water from private wells for these chemicals. Drinking water advice to residents was based on test results for PFOA and PFOS and the 2002 HBVs. If more than one PFC is detected in the same well, MDH evaluates the toxicity and potential health effects of all the chemicals together.

Modifying the HBVs for PFOA and PFOS

The discovery of PFCs in the environment and in people is recent, and federal EPA standards do not currently exist. Scientists around the world are studying the way PFCs act in the environment, and effects on laboratory animals and on workers who were exposed through manufacturing processes. As these studies become available, MDH scientists review them and evaluate the implications to ensure that the actions we take are protective of people’s health. When the HBVs were developed in 2002, there was limited toxicological information available.

New toxicological studies on the half-life of perfluorochemicals, studies in additional laboratory animal species, and more research on exposures during early life are some of the additional information that is now available, and the 2002 HBVs for PFOA and PFOS are being reviewed. Until that process can be completed, values protective of public health are being used to determine which homes should be provided with an alternate water supply. Granular activated carbon filters that are properly installed, operated and maintained are effective at removing PFCs from water.

Expanded Testing for Perfluorochemicals

The MPCA requested that the MDH Public Health Laboratory develop methods for additional perfluorochemicals in 2005 because these perfluorochemicals were found, used, or generated in Minnesota and suspected to be in groundwater. In addition to PFOA and PFOS, the new “Method 555” tests for

  • Perfluorobutane sulfonate (PFBS),
  • Perfluorobutanoic acid (PFBA),
  • Perfluoropentanoic acid (PFPeA),
  • Perfluorohexane sulfonate (PFHxS), and
  • Perfluorohexanoic acid (PFHxA).

Some of these chemicals have been detected in groundwater samples from monitoring wells at the Washington County Landfill. Water samples from private wells are also tested for these additional chemicals. In private wells, PFBA, PFPeA, PFHxS, and PFHxA have been found; PFBS has not been found. Three of the additional chemicals (PFPeA, PFHxS, and PFHxA) were only found in wells that had previous detections of PFOA and PFOS. However, PFBA was detected in wells that previously had no detections of PFOA and PFOS.

Due to limited toxicological research on these five PFCs, there isn’t enough scientific information to develop HBVs. However, based on their chemical characteristics, we anticipate that research will show that these five PFCs are less toxic for people than PFOA and PFOS. Until enough information is available to develop HBVs for these chemicals, MDH is using the interim values for PFOA and PFOS as substitutes for the other five chemicals, which is protective of people’s health.

Next steps

MDH and MPCA will be doing additional testing of private wells to determine the area affected by the five additional PFCs. Alternate safe drinking water will be provided when the drinking water testing results exceed the health guidelines.

If you have questions, please feel free to contact any of our staff listed below. MDH will
continue to monitor private and public wells affected by contamination from PFC disposal in
Washington County and continue to provide updates as new information and developments arise.


Contact person

Phone number

E-mail address

Groundwater and wells

Ginny Yingling



Health concerns

Jim Kelly



Sampling Jill Korinek 651-201-4913 jill.korinek@state.mn.us
Alternate water
Shawn Ruotsinoja 651-282-2382 shawn.ruotsinoja@state.mn.us
City of Lake Elmo Chuck Dillerud 651-777-5510 chuck.dillerud@lakeelmo.org

Printable information sheet: Update: Perfluorochemicals and Private Drinking Water Wells in Lake Elmo (PDF: 40KB/2 pages)


Updated Monday, September 19, 2011 at 10:07AM