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PFAS

Please note: This page contains information about perflukoroalkyl substances (PFAS), which were previously referred to as perfluorochemicals (PFCs). Learn more about this change.

Oct. 18, 2019: Sixth Woodbury Well has PFAS levels above health risk limit
On Friday, Oct. 18, the Minnesota Department of Health (MDH) issued a notice of health risk advisory for levels of poly- and perfluoroalkyl substances (PFAS) in a sixth Woodbury municipal water production well. Because some of the PFAS chemicals found in the drinking water can cause health effects based on daily consumption over a lifetime, the State of Minnesota calculates a health risk index (HRI) to determine if the combined health risk exceeds a certain level. 

Woodbury immediately made operational changes to its water system that will reduce use of the impacted well. Of Woodbury’s 19 municipal wells, water from six wells – based on the most current data – now have detectable levels of PFAS that on repeatable occasion exceed one or more thresholds established by the MDH. Several of these exceedances are only slightly above the heath parameters and have been below those values on prior sampling events. The MDH recommendations are based on daily consumption over a lifetime and have been developed to be protective of the most vulnerable. To learn more about PFAS, visit the MDH website or contact the MDH Site Assessment and Consultation Unit at 651-201-4897 or health.hazard@state.mn.us

Woodbury’s drinking water continues to meet State of Minnesota and Federal PFAS standards. The city – in coordination with MDH – has made operational changes limiting the use of the six impacted wellsStaff will be evaluating the water system’s ability to meet demand on peak use days in summer of 2020 with six of its 19 wells in reduced operation due to the presence of PFAS.

The city’s highest priority is the health and safety of its residents. Woodbury will continue working with the MDH to monitor, assess and sampling of its water. The public will be informed if/when new changes are detected. See testing results through September 2019.

Oct. 22 and 24, 2019: Public meetings scheduled
The Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Natural Resources (DNR) are holding two public informational meetings to discuss their ongoing efforts to provide safe drinking water to area residents.

  • Tuesday, Oct. 22, from 7-9 p.m. at Oak-Land Middle School, 820 Manning Avenue, in Lake Elmo
  • Thursday, Oct. 24, from 7 to 9 p.m. at Woodbury High School, 2665 Woodlane Drive, in Woodbury.
Representatives from the Minnesota Department of Health and the City of Woodbury also will be in attendance. Learn more at the 3M PFAS Settlement website.

Aug. 28, 2019: Expedited project awarded to and accepted by Woodbury
To help provide immediate assistance to communities impacted by PFAS, the state made a portion of the 3M Settlement dollars available early to help fund projects. Following a state submission and review process, Woodbury received $96,000 to study the level of effectiveness of “mixing” groundwater from clean wells with groundwater from wells with levels of PFAS that exceed the Health Risk Index for PFAS. The Minnesota Department of Health has indicated that “mixing” is an acceptable solution to treating PFAS contaminated wells. Woodbury has sought verification as to how well the technique is or may work in its municipal water supply. Results of the effort are expected in November 2019.

April 3, 2019: Minnesota Department of Health issues new Health-Based Guidance Values
The Minnesota Department of Health (MDH) issued new Health-Based Guidance Values (HBVs) for two chemicals in the group of chemicals known as perfluoroalkyl substances (PFAS), PFOS and PFHxS. The new PFOS value of 15 parts per trillion (ppt) replaces the 2017 value of 27 ppt. Only recently has enough scientific data been available to derive a value for PFHxS; the new HBV for PFHxS is 47 ppt. It replaces MDH’s previous approach of using the PFOS HBV as a “surrogate” for PFHxS.

The city changed its well operations to limit the use of the wells impacted by PFAS above established thresholds. These wells are only needed when water demand is high during summer months; when they are in operation, they are used as sparingly as possible and in a rotation with other wells that are not impacted by PFAS. Because of these existing operational changes, MDH indicated to city staff that no additional operational changes to the city’s water system are needed at this time. The water remains safe to drink.

For more information, MDH website.

March 2, 2018$850 million settlement provides funding for cleaning up drinking water
In 2010, Minnesota’s attorney general sued 3M Company alleging that the company’s production of chemicals known as PFAS had damaged drinking water and natural resources in the southeast Twin Cities metro area, including Woodbury. On Feb. 20, 2018, the State of Minnesota and 3M reached a settlement agreement, with the state receiving a grant from 3M for $850 million.

The court-approved agreement specifically outlines providing a clean, sustainable supply of drinking water as a top priority. It also indicates that improvements will be primarily focused on the cities of Woodbury, Afton, Cottage Grove, Lake Elmo, Newport, Oakdale, St. Paul Park and the townships of Grey Cloud Island and West Lakeland. Projects could include treating drinking water from existing wells, providing alternative sources of drinking water for cities or private well owners, or connecting homes served by private wells to municipal drinking water systems.

While the city's water is safe to drink today, there have been significant operational changes made due to the presence of PFAS in the aquifer. The city looks forward to working with the state agencies and other impacted communities to develop water treatment solutions that will provide safe drinking water for generations to come.

Details about the settlement and how the funds could be used are available on the Minnesota Pollution Control Agency website.

Community members who have questions about Woodbury water operations may contact Public Works at publicworks@woodburymn.gov or 651-714-3720.

View the press release from the PCA

Private Water Supply Wells
As a result of the EPA’s new guidance and MDH updated HBV for PFOA and PFOS, MDH is sampling private wells within Washington County and will issue additional drinking water advisories as needed. Until their private wells are tested, residents who have concerns about their health can take steps to reduce their potential exposure to PFAS. Information on point-of-use filters and other steps people can take in their homes can be found on the MDH website.

Residents who have questions about their private water supply well and whether it is impacted by this change should contact MDH.

Below is a chart outlining PFAS monitoring results for Woodbury municipal wells completed as of Sept. 10, 2019.

PFAS type

Amount (combined range in all 19 wells)

MDH Health Risk Limit (HRL)

MDH Health Based Guideline (HBV)

2016 EPA Guideline

PFBA

<0.05 to 0.44 parts per billion (ppb)

7 parts per billion (ppb) or 7,000 parts per trillion (ppt)

N.A.

N.A.

PFOA

<0.035 to 0.045 ppb

0.035 ppb or 35 ppt

N.A.

70 ppt

PFOS

<0.015 to 0.033 ppb

0.3 ppb or 300 ppt

0.015 ppb or 15 ppt

70 ppt

PFBS

<0.05-0.015 ppb (reported below the laboratory reporting limit)

7 ppb or 7,000 ppt

2 ppb or 2,000 ppt

N.A.

PFPeA, PFHxA 

<0.05 to 0.016 ppb (reported below the laboratory reporting limit)

No HRL established

N.A.

N.A.

PFHxS

<0.025-0.073 ppb

No HRL established

0.047 ppb or 47 ppt

N.A.


“Parts per billion” means the number of units of the chemical, in its pure form, found in every billion units of water. 

“Parts per trillion” means the number of units of the chemical, in its pure form, found in every trillion units of water.

For a general perspective, the City of Woodbury pumped approximately 2.6 billion gallons of water in 2017. That means a PFAS detected at a level of 0.025 ppb (parts per billion) would equal about an 8-ounce cup (or 0.06 gallons) of the substance in 2.6 billion (2,600,000,000) gallons of water.

About PFAS
PFAS were made by 3M in Cottage Grove and by other companies around the world for use in household and industrial products. PFAS wastes were disposed of in several landfills in Washington County including Lake Elmo, Oakdale and in southern Woodbury near Woodbury Drive (3M Woodbury site). The source of the PFAS in the Woodbury groundwater has been identified as these landfills.

Visit the MDH website for more information about PFAS in groundwater.

Remediation Activities
In 2011, the Minnesota Pollution Control Agency (MPCA) completed remediation activities at these sites to reduce the amount of pollutants released from these sites in the future.

3M, under direction from the MPCA, continues active site remediation. For the Woodbury site, remaining contamination is captured by pumping approximately 1.25 billion gallons of water annually to a treatment plant and discharging it to the Mississippi River.

Visit the MPCA website for more information about the remediation activities.