Treatability Study Work to Begin 10th Street Superfund Site, Columbus, Nebraska
In late February 2006, the U.S. Environmental Protection Agency (EPA) will begin a Treatability Study for the 10th Street Superfund Site in Columbus, Nebraska. The Treatability Study is the first phase of the chemical oxidation remedy for the ground water contaminant plume.
The 10th Street Site is located in the south-central portion of the city of Columbus in Platte County, Nebraska. In 1983, the Nebraska Department of Health discovered contamination in Columbus’ water supply wells. Follow-up sampling detected Trichloroethylene (TCE) in four of the municipal wells. The site was proposed for the National Priorities List (NPL) in 1989, and was officially listed on the NPL in August 1990.
In February 1995, EPA issued a Record of Decision (ROD) upon completion of a Remedial Investigation/Feasibility Study (RI/FS). The ROD called for ground water monitoring with institutional controls, with a contingency for extraction and discharge to the Loup River if results indicate unacceptable risks.
Ground water monitoring conducted after issuance of the ROD detected elevated concentrations of Tetrachloroethylene (PCE) and TCE in a monitoring well that had previously been considered a background well for the site. A subsequent site investigation conducted in the fall of 1998 indicated a major source of PCE and TCE ground water contamination coming from a dry-cleaning facility located over a mile upgradient from the original site.
EPA implemented a removal action which included an Air Sparging/Soil Vapor Extraction (AS/SVE) system to address soil and ground water contamination at the upgradient source area. A second RI/FS was completed to delineate the extent of contamination and evaluate alternatives to address the contamination.
EPA finalized an interim remedial action ROD on September 20, 2001, that included extraction of contaminated ground water at municipal well W-1, plume interception by extraction wells, treatment and discharge of contaminated ground water, and continued operation of the AS/SVE system. The ground water extraction and treatment (GET) system was designed, constructed, and is currently in operation.
RI/FS activities continued through the implementation of the interim remedial action. In May 2005, EPA prepared another FS to identify and evaluate remedial alternatives for the final remedial action. In the September 2005 final ROD, the final remedy called for continued operation of the GET and AS/SVE systems, limited action for contaminated soils in the other source areas and chemical oxidation in the plume located upgradient of the GET system.
The Study will include ten days of field work including drilling of soil borings and installing temporary wells. Insitu ground water treatment through chemical oxidation will be conducted later in March. After treatment, sampling will be performed at regular intervals to monitor the contamination, and determine if the oxidating chemicals are at correct levels.
The Study will take place in two areas in Columbus; 18th Street between 21st and 22nd Avenue and an area near Highway 30 and 25th Avenue. It is anticipated that 18th Street between 21st and 22nd Avenue, 25th Avenue directly south of 23rd Street, and the alley between 23rd and 22nd Street west of 25th Avenue will need to be blocked during the week in late February. The area between 21st and 22nd Avenue on 18th Street will be blocked again in late-March during the ground water treatment to complete the field work. After the treatability study, the design of the chemical oxidation remedy will be completed. Future ground water treatments may take place later this year.
Site-related documents provide details of the nature and extent of contamination and the work that has been completed at the 10th Street site. These documents are part of the Administrative Record File, available during normal business hours at the following locations:
Columbus Public Library
2504 14th Street
EPA Region 7
901 N. 5th Street
Kansas City, Kansas
If you have questions or need additional information, please contact:
Community Involvement Coordinator
EPA, Region 7,
Office of External Programs
901 North 5th Street
Kansas City, Kansas 66101
E-mail: Beckie Himes (firstname.lastname@example.org)