Congressional District # 06
BAYTOWN TOWNSHIP GROUND WATER PLUMEEPA ID# MND982425209
Last Updated: March, 2015
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 located primarily in the surficial aquifer, the Prairie du Chien Aquifer, and the Jordan Sandstone Aquifer, and in certain areas, the Tunnel City Aquifer. The contaminated groundwater plume covers approximately seven square miles. 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 homes, 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 ResponsibilityCurrently the site is being addressed through State of Minnesota actions with funding by EPA. Early phases of the cleanup were implemented through potentially responsible party (PRP) actions.
Threats and Contaminants
The primary contaminant of concern in groundwater at the site is trichloroethylene (TCE).
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 EPA 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. In 2012, MPCA maintained 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 Focused 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.
In 2013, MDH issued a new lower health-based level (known as an HBV) for TCE and advised against drinking water that exceeds that level. In response, MPCA is in the process of expanding the number of private wells for which they supply GAC treatment.
In 2014, MPCA began a Feasibility Study to investigate how to address lower-level TCE contamination present in two additional City of Bayport drinking water wells. Water from the two additional wells currently meets Federal drinking water standards, but there is a potential for contaminant levels to increase. The study is expected to be completed in mid-2015 and MPCA expects to modify the existing remedy for this part of the site and take additional actions as soon as practical.
ContactsRemedial Project Manager, U.S. EPA
leah evison (firstname.lastname@example.org)
Community Involvement Coordinator, U.S. EPA
AliasesBAYTOWN TOWNSHIP GROUNDWATER PLUME/LAKE
BAYTOWN TWP GROUNDWATER CONT
LAKE ELMO AIRPORT GROUNDWATER PLUME