Region 5 Superfund (SF)

U.S. EPA REGION 5
WASHINGTON COUNTY
BAYTOWN TOWNSHIP

Congressional District # 06

BAYTOWN TOWNSHIP GROUND WATER PLUME

EPA ID# MND982425209
Last Updated: November, 2011

Site Description

The Baytown Township Groundwater Plume site is located east of the village of Lake Elmo, Washington County, Minnesota. The plume extends into Baytown and West Lakeland Townships and continues eastward approximately four miles to the St. Croix River. Baytown Township is a rapidly developing rural/suburban residential area on the eastern edge of the Minneapolis-St. Paul metropolitan area. The contaminated groundwater is primarily in the Prairie du Chien-Jordan aquifer, which is the major source of drinking water for many residents in the area through private and residential wells. The Lake Elmo airport is located near the western end of the plume and is currently administered by the Metropolitan Airports Commission (MAC). An estimated 8,000 people live in the area; 80 percent of the residents use private wells for their water supply.

Site Responsibility

The site is being addressed through state of Minnesota and potentially responsible party actions.

Threats and Contaminants

There are two volatile organic compounds (VOCs) of concern in the groundwater contaminant plume - trichloroethylene (TCE) and carbon tetrachloride.  The Minnesota Pollution Control Agency (MPCA) believes that use of the chlorinated solvent TCE at a former metal working facility at the location of the Hagberg Country Market was the major source of site ground water contamination.  The use of TCE at the Lake Elmo airport likely also have caused some of the TCE groundwater contaminant plume.  On the north side of the plume there are a few former grain storage bins which MPCA believes were the potential source of carbon tetrachloride that was previously detected in that area of the plume. 

Cleanup Progress

The Minnesota Department of Health (MDH) first detected TCE in private wells in 1987. Between 1987 and 2003, the MPCA, MDH, MAC, and the Washington County Department of Health collected thousands of samples from private wells. MDH conducted a public health assessment and created a well advisory area.  MPCA and MAC have installed over 30 monitoring wells in the area.  MPCA signed a Record of Decision (ROD) in 2000 which calls for cleanup in three areas:  the groundwater plume and private wells; the city of Bayport municipal well #2; and the source area. 

The remedy for the groundwater plume and private wells includes plume monitoring and installation and maintenance of granular activated carbon (GAC) treatment units for private wells that exceed 5 micrograms per liter (ug/l or "parts per billion") TCE.  Installation of GAC units has been completed at aproximately 125 existing wells. The plume currently appears to be stable; however, a small number of additional units may be needed annually due to new home construction or interior plume variation. If the health-based limit for TCE is lowered in the future, GAC units would be needed at additional residential wells. The site currently is undergoing a groundwater optimization study by the U.S. Army Corps of Engineers under contract to EPA, to be completed in winter 2011. 

The remedy for the Bayport Municipal Well #2 includes installation of an air stripper treatment system for Municipal Well #2, for which construction is complete and operational.

The source area remedy includes both containment and treatment of source area groundwater.  Construction of a hydraulic barrier to contain groundwater at the source area is complete and operating.  A pilot study of one treatment method (in-situ chemical oxidation) for this area was conducted, and currently a second technology (in-situ bio-stimulation) is being studied.  If further study indicates it the second technology is likely to be effective, construction is anticipated in 2011. 

Contacts

Remedial Project Manager, U.S. EPA
leah evison (evison.leah@epa.gov)
(312) 886-2064

Community Involvement Coordinator, U.S. EPA
cheryl allen
(312) 353-6196

Aliases

BAYTOWN TOWNSHIP GROUNDWATER PLUME/LAKE
BAYTOWN TWP GROUNDWATER CONT
LAKE ELMO AIRPORT GROUNDWATER PLUME

 

Site Profile Information

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