Superfund Information Systems: Site Profile

Superfund Site:

KELLOGG-DEERING WELL FIELD
NORWALK, CT

Cleanup Activities

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Background

The Kellogg-Deering Well Field site is located in Norwalk, Connecticut. It consists of a 10-acre municipal well field and adjacent areas that contribute to the well field contamination. Groundwater sampling identified a significant source of contamination below the Elinco/Pitney Bowes/Matheis Court Complex at the eastern edge of the site. The well field supplies about 50 percent of Norwalk’s public drinking water supplies. Following construction of the site’s long-term remedy, groundwater treatment and environmental monitoring are ongoing.

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What Is Being Done to Clean Up the Site?

The site is being addressed through federal, state and potentially responsible party (PRP) actions. Wellhead treatment and controlling the sources of soil and groundwater contamination have reduced the potential of exposure to hazardous substances in the drinking water and will continue to protect the neighboring residents while final cleanup activities at the site are completed.

EPA has conducted several five-year reviews of the site’s remedy. These reviews ensure that the remedies put in place protect public health and the environment, and function as intended by site decision documents. The most recent review concluded that response actions at the site are in accordance with the remedy selected by EPA and that the remedy continues to be protective of human health and the environment in the short term. Exposure pathways that could result in unacceptable risks are being controlled through the wellhead treatment system and institutional controls that prevent use of contaminated groundwater.

The remedy will be protective of human health and the environment in the long term when VOC mass removal achieves site cleanup standards. Groundwater extraction and treatment is ongoing. Based on a review of recent groundwater sampling, the possibility exists that the current groundwater extraction and treatment system may not achieve restoration of the groundwater. Additionally, should the Source Area property be redeveloped, further actions may be needed to prevent inhalation of contaminated soil vapors so that the remedy remains protective in the long term.

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What Is the Current Site Status?

The site is being addressed in three long-term remedial phases focused on wellhead treatment, source control, and downgradient aquifer management.

Wellhead Treatment:
The Water Department installed an aerator in 1981 at one of the wells to reduce the concentration of volatile organics in the groundwater. In 1988, an additional air stripper increased the removal of volatile organic compounds (VOCs) at the wellfield. The air stripper is part of the water treatment plant and will remain in operation until the contaminants are reduced to EPA-approved levels. Contaminants are being removed from the water by air filtering the volatile contaminants into a gaseous state. The treated water is discharged into the existing conventional water treatment plant and distribution system.

Source Control:
The remedy selected by EPA for controlling the source of contamination involves removal of contaminants from the soil with vacuum extraction, extraction and treatment of contaminated groundwater, and institutional controls to prevent exposure during the cleanup process. Construction of this treatment facility finished in September 1996. The soil vapor extraction system remained operational until 2005 when testing confirmed the soil cleanup standards had been met.  The soil extraction system was dismantled in 2006.  Subsequent to this action, in preparation for development of the property, the owner excavated and disposed of offsite more soil to meet Connecticut regulations

The groundwater extraction and treatment system remains operational. Air and groundwater monitoring take place as part of operation and maintenance activities at the site.

Downgradient Aquifer Management:
Through groundwater monitoring, EPA has been tracking the extent and migration of contaminants in the area downgradient from the source of contamination and above the well field. Sampling of indoor air in homes in the downgradient area confirmed that contaminant vapors were not posing a risk. EPA will evaluate the impact of the cleanup at the wellhead and source control areas on reducing the levels of contaminants downgradient from the source and above the well field over time.

Groundwater treatment and environmental monitoring are ongoing.

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Activity and Use Limitations

At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use. They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.

For more background, see Institutional Controls.

Institutional Controls are required for this site.

This site requires ICs because a decision document, such as a Record of Decision, has documented some level of contamination and/or remedy component at the site that would restrict use of the site. In order to determine the current status of ICs for this site, the site contacts should be consulted.

ICs are generally defined as administrative and legal tools that do not involve construction or physically changing the site. Common examples of ICs include site use and excavation restrictions put in place through State and local authorities like zoning, permits and easements. ICs are normally used when waste is left onsite and when there is a limit to the activities that can safely take place at the site (i.e., the site cannot support unlimited use and unrestricted exposure) and/or when cleanup components of the remedy remains onsite (e.g., landfill caps, pumping equipment or pipelines). Effective ICs help ensure that these sites can be returned to safe and beneficial use.
 
Disclaimer: This information is being provided by EPA as an informational tool to further assist the public in determining the types of restrictions that may be in place at National Priorities List sites being addressed by EPA under the Superfund program. In addition to the areas addressed by the institutional controls identified on this web site there may be other areas on the property that require restrictions on use of the property that are not captured in this EPA database. States and other entities may have implemented laws or restrictions applicable to this site. The information provided herein does not replace a title search or meet "All Appropriate Inquiry" requirements. U.S. EPA encourages users to review the Site files to obtain information regarding remedy components, containment systems and the land use for which cleanup standards were selected for these sites. More information and links can be found on the site profile page and the EPA regional offices may also be contacted.

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