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Fact Sheet

July 2010

EPA Initiates the Remedial Investigation/Feasibility Study, Southwest Jefferson County Mining Site, Jefferson County, Missouri


On September 23, 2009, the U.S. Environmental Protection Agency added the Southwest Jefferson County Mining Site to the National Priorities List (NPL). The NPL is a list of the nation's hazardous waste sites with the highest priority for cleanup. These sites are eligible for extensive, long-term response action money authorized by Congress under the Superfund program.

Next month, EPA Region 7 will begin the site-wide Remedial Investigation/ Feasibility Study (RI/FS) for the Southwest Jefferson County Mining Site. EPA staff and contractors will be working in the county to gather the environmental samples needed for the remedial investigation.


Jefferson County is part of Missouri's Old Lead Belt, where lead mining has occurred for several hundred years. Mining activities in Jefferson County have contributed to elevated levels of lead in soil, ground and surface water in the area. Some county residents have also unknowingly purchased lead-contaminated soil for property and landscaping improvements.


During the remedial investigation, EPA gathers data needed to determine the nature and extent of contamination at the site, establishes site cleanup criteria, identifies preliminary alternatives for remedial action, and supports technical cost analyses of alternatives. After the RI has commenced, EPA conducts the feasibility study, which considers different alternatives for cleaning up the site and recommends selection of a cost-effective alternative.

EPA will ultimately present the findings of the investigation to the community and ask for comments on EPA's proposed actions before making decisions about site cleanup.

During the remedial investigation process, EPA will continue to address high levels of lead contamination at residences within the site by removing contaminated soil and replacing with clean soil. EPA will also continue to address contamination in private water wells by providing an alternative drinking water source to residents whose drinking water has been identified with lead or cadmium above levels of concern.


EPA has collected soil samples from 1,900 properties located within the site. To date, 331 properties have been identified with lead-contaminated soil above 1,200 parts per million (ppm). At this level, EPA prioritizes properties for cleanup as time-critical removals. EPA has completed time-critical removals at 260 properties. Once EPA has conducted the RI/FS, submitted a proposed plan to the public and developed the record of decision, EPA will determine the cleanup criteria for addressing properties with contamination below 1,200 ppm. These properties will be cleaned up during the remedial action phase.

EPA has collected water samples from 630 private water wells in the site. EPA is providing bottled water to 38 residents whose wells have been identified with lead or cadmium above drinking water standards.


EPA wants to help affected communities understand the technical information related to a site. EPA's Technical Assistance Grant Program provides up to $50,000 for a qualified citizens group to hire independent technical advisors. The advisors can help citizens interpret technical data, understand site hazards, and become more knowledgeable about the different technologies used to clean up sites.


EPA has compiled the site administrative record file. The administrative record file is the official record for the site and contains site reports and descriptions of activities and other documents used to determine the appropriate actions to take at the site. The administrative record file is available for review during normal business hours at the following locations:

De Soto Public Library
712 South Main Street
De Soto, Missouri

EPA Region 7
Records Center
901 North 5th Street
Kansas City, Kansas


If you have questions about this fact sheet or want additional information about the site, please contact:

Dianna Whitaker
Community Involvement Coordinator
U.S. EPA Region 7
Office of Public Affairs
901 North 5th Street
Kansas City, KS 66101
Phone: 913-551-7598 or
Toll Free: 1-800-223-0425

Preston Law
Remedial Project Manager
U.S. EPA Region 7
Superfund Division
901 North 5th Street
Kansas City, KS 66101
Phone: 913-551-7097
Toll-Free: 1-800-223-0425

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