Region 5 Superfund

U.S. EPA REGION 5
WASHINGTON COUNTY
BAYTOWN TOWNSHIP

Congressional District # 06

BAYTOWN TOWNSHIP GROUND WATER PLUME

EPA ID# MND982425209
Last Updated: December, 2012

Site Description

The Baytown Township Groundwater Plume site is located in Washington County, Minnesota and includes portions of Baytown Township, West Lakeland Township, the City of Bayport and the City of Lake Elmo.  The site consists of a contaminated groundwater plume and its source area.  The contaminated groundwater plume covers approximately seven square miles and discharges into the St. Croix River.  The primary source area for the contamination is a property located at 11325 Stillwater Boulevard in Lake Elmo.  This property was used by a metal-working facility from 1940 to 1968.  Land above the groundwater plume includes farmland, rural residential houses, commercial buildings, Lake Elmo Airport and developed areas of the City of Bayport.  Most of the plume area is served by private wells and a public water supply is available in portions of the cities of Lake Elmo and Bayport.

Site Responsibility

Currently the site is being addressed through State of Minnesota actions.  Early phases of the cleanup were implemented through potentially responsible party actions.

Threats and Contaminants

The primary contaminant of concern in groundwater at the site is trichloroethylene (TCE). 

Cleanup Progress

The Minnesota Department of Health (MDH) first detected TCE in private wells in 1987 and created a Special Well Construction Area to protect residents in 1988.   The site was listed on the State's Permanent List of Priorities in 1988 and on the National Priorities List in 1994.  Beginning in 1987, the MPCA, MDH, Metropoplitan Airports Commission and the Washington County Department of Health collected thousands of samples from private wells.  

In 2000, MPCA selected a remedy for the groundwater plume and private wells which requires plume monitoring and installation and maintenance of granular activated carbon (GAC) treatment units for private wells that exceed the State's Health Risk Limit for TCE (currently 5 micrograms per liter or parts per billion).  Early phases of the remedy were implemented by the Metropolitan Airports Commission under agreements with MPCA, including installation of GAC treatment systems in homes.  Following discovery of the primary source area on Stillwater Boulevard, the responsibility for remedy implementation overall was shifted to the State.  MPCA currently samples private water supply wells and installs, changes out, maintains, and removes GAC filter systems using a State contractor.  As of 2012, MPCA maintains GAC filters in approximately 180 homes.  For wells located on properties platted and approved for development after 2002, township ordinances require property owners to test and treat their own drinking water.  MPCA also regularly samples a network of monitoring wells.

In 2007, MPCA amended the remedy to add actions for the City of Bayport Municipal Well #2 and for the source area.  The remedy for the Bayport Municipal Well #2 included installation of an air stripper treatment system.  The treatment systen was constructed and has been operational since 2007.  The source area remedy includes both containment and treatment of source area groundwater and dense non-aqueous phase liquids (DNAPL).  Construction of a hydraulic barrier to contain groundwater at the source area is complete and the system has been operating since 2008.  A pilot study of one treatment method for the source area has been conducted and a Focussed Feasibility Study for a second phase of treatment was begun in 2011.   

In 2012, EPA and MPCA conducted the latest five-year review of the site.  This review concluded that the site remedy currently being implemented protects human health and environment in the short-term, but that certain actions should be taken to ensure long-term protection.  These actions include responding to any changes in the State's Health Risk Limit or the Federal Maximum Contaminant Level for TCE; assessing whether natural attenuation is sufficient to return the entire groundwater plume to drinking water levels in a reasonable timeframe; and monitoring concentrations in other City of Bayport municipal wells.

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

This profile provides you with information on EPA's cleanup progress at this Superfund site.