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Congressional District # 01


EPA ID# WID980820062
Last Updated: May, 2015

Site Description

The Delavan Municipal Well #4 Superfund Site is located within the corporate limits of the City of Delavan, Wisconsin, and is defined as the contaminated aquifer used by the City of Delavan Municipal Well #4. A portion of the contaminated aquifer is generally located on the property occupied by Sta-Rite Industries, Inc.

There are more than 3,000 people living within one mile of the site. The population of Delavan relies on municipal water, and no private wells have been identified in the area. The land use in the area is currently mixed use and includes commercial, residential and light industrial. The distance from the site to the closest residence is 500 feet.

Site Responsibility

The Well #4 site is being addressed through federal, state, and potentially responsible party (PRP) actions.

Threats and Contaminants

In March 1982, during a public well sampling program by the Wisconsin Department of Natural Resources (WDNR), trichloroethylene (TCE) was detected in the City of Delavan Municipal Well #4. The TCE exceeded the suggested levels for water quality standards as set by the Wisconsin Department of Health and Social Services. 1,1,1-trichloroethane (TCA) and tetrachloroethylene (also known as perchloroethylene or PCE) also were identified. As a result, Municipal Well #4 was closed in 1982 and not included in the municipal water supply system until it was again safe to use the well. TCE, TCA, and PCE are volatile organic compounds (VOCs) and are identified as the contaminants of concern at this site. People can be exposed to VOCs by drinking or bathing with VOC-contaminated water.

EPA proposed the Delavan Municipal Well #4 site to the National Priorities List (NPL) in 1983 and finalized the site on the NPL in 1984. Sta-Rite Industries, Inc. has been identified as a potential source of the groundwater contamination entering Municipal Well #4. TCE, TCA, and PCE were used in manufacturing processes and cleaning processes at the Sta-Rite facilities up until 1977.

Cleanup Progress

The PRP at the site took steps to contain contaminated groundwater near the site through the installation of a groundwater well extraction system in 1984 and a soil vapor extraction system in 1988.

In January 1993, a focused feasibility study for interim remedial measures was approved which called for the construction of an expanded soil vapor extraction and groundwater extraction well system (SVE/GWE). WDNR, in consultation with EPA, approved this Interim Remedial Action in 1993. The SVE/GWE system was constructed by the PRP and went online in June 1994. The extraction system controlled three source areas. The SVE segment of the project removed VOCs at the rate of 26 pounds per year. The treatment ensured that concentrations of contaminants entering the water distribution system are consistently below levels that are considered a health risk.

In September 2000, EPA signed a Record of Decision to select continuation of the operation of the interim remedial measure (see above) as the final remedy for the site. As long as the interim remedial measure continues to operate successfully, no further action will be necessary.

Since 2000, the PRP has prepared annual operation and maintenance reports. These reports have shown a steady decline in the VOCs in groundwater and soils at the site. Because of the significant reductions in VOC impacts observed in the site monitoring wells, operation of the SVE/GWE system was discontinued. In addition, sampling of the raw water intake at Well #4 demonstrated that VOCs are no longer present and Well #4 is back on line and fully functional. Seven groundwater extraction wells remain in operation to control off-site migration of groundwater contamination.

WDNR, in consultation with EPA, completed the first two five-year reviews at the site. The purpose of a five-year review is to determine whether the remedy at a site is protective of human health and the environment. The five-year reviews found that the remedy at the site is protective of human health and the environment because no groundwater exceeding the state's Preventative Action Limits (PALs) is migrating beyond the Sta-rite property boundary. The ROD did not call for institutional controls (ICs) on the Sta-Rite property to restrict exposure, but EPA and WDNR will review the need for ICs. If ICs are determined to be needed, EPA will document that determination in an appropriate remedy decision document. WDNR and EPA plan to complete the site's third five-year review by August 2015.


Remedial Project Manager, U.S. EPA
colleen moynihan (moynihan.colleen@epa.gov)
(312) 353-8196





Site Profile Information

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


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