Hazardous Sites and Substances in Minnesota
Lake Elmo Private Wells
November 2006

Note: This is an archived page.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

This Web site provides updated information about public health issues related to the perfluorochemical (PFC) groundwater contamination in western Lake Elmo, Washington County, Minnesota. The Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health (MDH) are working together on this investigation. The PFC contamination in Lake Elmo is not related to the trichloroethene (TCE) contamination found in the groundwater of Baytown/West Lakeland Townships.
PFCs are a family of chemicals that have been used to make products that resist heat, stains, water, oil and grease. Wastes containing these chemicals were disposed decades ago in the former Washington County Landfill, the Oakdale Dump Superfund site (located near T.H. 5 and Granada Ave in Oakdale), and other locations.  PFCs have been found at various levels in groundwater at the former landfill and dump, in private wells in the area, and in the Oakdale municipal wells.

At this time MDH staff are collecting private well samples in Lake Elmo for analysis of the following PFCs at the MDH Public Health Laboratory:

  • Perfluorooctane sulfonate (PFOS)
  • Perfluorohexane sulfonate (PFHxS)
  • Perfluorobutane sulfonate (PFBS)
  • Perfluorooctanoic acid (PFOA)
  • Perfluorohexanoic acid (PFHxA)
  • Perfluoropentanoic acid (PFPeA)
  • Perfluorobutanoic acid (PFBA)

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Lake Elmo Public Meeting - September 14, 2006
A public meeting was held Thursday, September 14 at Oak-Land Junior High School to provide an update for residents on the PFC groundwater investigation in the Lake Elmo area. Representatives from MDH, MPCA, Washington County Public Health and Environment, and the City of Lake Elmo provided information to residents. Staff was also available for individual questions and concerns from citizens before and after the meeting. The presentations from the meeting are available below.

A Brief Overview of PFCs and Groundwater Investigation in Lake Elmo (PDF: 941KB/22 pages)
Summary of Response Actions: Minnesota Pollution Control Agency (PDF: 446KB/8 pages)
City of Lake Elmo: Water Extension Project(PDF: 2,369KB/7 pages)

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Private Well Sampling
To date, a total of 385 private wells have been sampled as part of the ongoing investigation of PFCs in the groundwater of western Lake Elmo. Other areas of Lake Elmo, including the city's municipal wells and the Cimarron Park wells, are not affected by the PFC contamination.

MDH and MPCA have developed a sampling frequency plan for private wells sampled for PFCs. Monitoring includes quarterly, semi-annual, or annual sampling based on the concentration of PFCs detected in each well. Some "sentry" wells, located within and along the edges of the PFC plume, will also be sampled to monitor changes in the size and concentration of the affected area. Monitoring of private wells will continue.

MDH is currently reviewing the 2002 Health-Based Values (HBVs) for PFOS and PFOA. The MDH HBV is the concentration of a groundwater contaminant that poses little or no risk to health, even if consumed daily over a lifetime. No HBVs exist for the other PFCs; however they are thought to be less toxic and generally do not accumulate in the body as do PFOS and PFOA. While the HBV review process is underway, as a cautious public health approach MDH is applying the following guidelines to evaluate PFC levels in private wells:

  • PFOS, PFHxS, PFBS: 0.6 parts per billion (ppb)
  • PFOA, PFHxA, PFPeA, PFBA: 1.0 ppb

To date, MDH has issued advice to 149 residences in Lake Elmo and one residence in Oakdale recommending that their water not be used for drinking or cooking.  An additional 177 private wells have been found to contain low concentrations of PFCs, below MDH guidelines. 59 private wells in Lake Elmo and 6 in Oakdale were found to contain no PFCs.

The Special Well Construction Area (SWCA) already in place due to other contamination from the Ramsey-Washington County Landfill may be expanded based on the results of the sampling. Within the Special Well Construction Area, contractors and property owners must submit a written request and well construction plan to the MDH and must receive written approval before construction, repair, or sealing of a well. MDH and MPCA staff are in the process of determining which areas in Lake Elmo may be included in the expansion. More information on the SWCA can be found by following the link below.  For SWCA questions, please contact Patrick Sarafolean at MDH (651-643-2110).

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Surface Water Sampling
Water samples were collected from Raleigh Creek, which drains the wetlands at the Oakdale disposal site and flows east through the northern edge of the Tablyn Park neighborhood and into Eagle Point Lake in the Lake Elmo Park Reserve.  The samples contained PFCs at concentrations similar to those detected in private wells near the creek.  The surface water sampling and distribution patterns of PFOS, PFOA, and PFBA, suggest that some of the PFCs in the groundwater in Lake Elmo may be a result of transport by Raleigh Creek from the Oakdale disposal site.

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Update on Response Actions
The City of Lake Elmo is in the process of extending its municipal water supply to serve two neighborhoods affected by the PFC contamination: Tablyn Park and Lake Elmo Heights. This work is expected to be completed by the end of 2006. Well owners in those two neighborhoods who received advice from MDH in 2006 to not use their well water for drinking or cooking are being provided with bottled water by the MPCA until the city water connection is made. 

Homeowners outside those two neighborhoods who receive advice from MDH not to use their well water for drinking or cooking are being provided with granular activated carbon (GAC) filters by the MPCA.  Sampling of the GAC filters has shown that they are effective at removing PFCs.  For more information on GAC filters, please follow the link below.

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Additional Information

City of Lake Elmo Attention: Non-MDH link.

Water Treatment Using Carbon Filters: GAC Filter Information

Special Well and Boring Construction Areas

Minnesota Pollution Control Agency: Perfluorochemicals

Environmental Protection Agency: Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers

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Updated Thursday, December 15, 2011 at 08:42AM