Sites and Substances in Minnesota
Township Groundwater Contamination Site
This web site provides information about public health issues related to TCE contamination in the Baytown Township Groundwater site in Washington County, Minnesota. Trichloroethylene, also known as trichloroethene or TCE, is a chemical solvent often used for degreasing metal parts. It was first found in the groundwater in the area in 1987, and the site is listed as a state and federal Superfund site. TCE is a human carcinogen and has been linked to adverse immune system effects.
For more information about TCE:
Trichloroethylene (TCE) and Your Health webpage
TCE in Drinking Water and Groundwater Contamination Sites
(PDF: 233KB/2 pages)
In 2013, MDH re-evaluated the current Health Risk Limit (HRL) of 5 micrograms per liter (µg/L), which was based on the U.S. Environmental Protection agency’s Maximum Contaminant Level (MCL). This re-evaluation was conducted to ensure the MDH guidance was based on the most recent toxicological studies and scientific methods, and resulted in an updated Health Based Value (HBV) of 0.4 µg/L.
For more information about the updated Health Based Value, please see the Technical and Application Information for Trichloroethylene (TCE) webpage.For more on the health based value history and process, please visit MDH Health-Based Guidance for Water webpage.
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TCE has been detected in approximately 400 private wells, primarily in Baytown and West Lakeland townships, but also in Bayport. Since 2002, the MPCA has provided bottled water and/or whole-house granular activated carbon (GAC) filters to every residence where TCE concentrations were at or above the HRL of 5 µg/L. Based on the most recent samples available, there may be approximately 130 wells with TCE concentrations at or above the new HBV of 0.4 µg/L, but below the previous HRL of 5 µg/L. Many of these wells will need to be resampled to confirm the TCE levels, as the previous samples are more than a year old.
TCE has also been detected in the Bayport municipal wells. Well #2 exceeded the federal Maximum Contaminant Level (MCL) of 5 µg/L in 2005. As a result, the MPCA constructed a water treatment system that removed TCE from the water pumped from this well. At this time, most of the drinking water for Bayport comes from Well #2. TCE concentrations in wells #3 and #4 have been increasing over time, with the most recent concentrations being 2.8 and 2.3 µg/L respectively.
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In 2013, the MPCA will be sampling a large number of private wells to identify any that currently exceed the new HBV of 0.4 µg/L. MDH will review the new data and issue well advisories, as needed. For more information about MPCA activities at the site, see Baytown Township Groundwater Contamination Site.
After the first round of sampling is completed, MDH will review all of the data and prepare a Site Review and Update report; this will likely be released in late 2013 or early 2014. MDH’s Well Management program will also review the data and determine whether the boundaries of the SWCA need to be expanded.
State and local government representatives will also consider what, if any, alternate, long-term solutions are available for providing a clean water supply to the Baytown-West Lakeland Township area. Bayport city officials are already working with MPCA and MDH to explore options for reducing TCE levels in their water supply.
*Properties that were platted after April 9, 2002 are not sampled by the MPCA and are not eligible for a state-provided GAC filter system. These properties are governed by specific township ordinances. For more information on these ordinances, residents should contact their township offices.
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The MPCA samples all of the wells within the area of TCE contaminated groundwater (with the exception of wells on properties platted after April 9, 2002) and a select number of wells outside the area of contamination to track the edges of the plume. The sampling frequency of a well is based on the concentration of TCE in the water; wells with higher TCE levels are sampled more often than those with lower levels.
Residents who are not included in the MPCA’s groundwater sampling program, or who want their water tested sooner than MPCA is able to collect a sample, may contact Washington County and pay to have their water sampled. These samples will be analyzed by the Minnesota Public Health Laboratories and the results reviewed by MDH staff, who then send the results in a letter. For more information on how to request a sample, see the Washington County webpage, Water Tests, or download a Washington County VOC Sampling Request Form.
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