Announcing the Availability of the Third Five-Year Review Report, 10th Street Superfund Site, Columbus, Platte County, Nebraska
The U.S. Environmental Protection Agency (EPA) conducts regular checkups, called five-year reviews, on Superfund sites where cleanups have been completed. These regular five-year reviews are required by the Superfund law [42 U.S.C. Section 9621 (c)] to make sure the site remains safe and the cleanup actions continue to protect human health and the environment. EPA has completed the third five-year review for this site. Previous reviews were completed in February 2000 and September 2005.
The 10th Street Superfund Site is located in the south-central portion of the city of Columbus, Nebraska. In 1983, the Nebraska Department of Health discovered contamination in Columbus' water supply wells. Follow-up sampling detected Trichloroethene (TCE) in four of the municipal wells.
In February 1995, EPA issued a Record of Decision (ROD) following 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 unacceptable risks were indicated.
Ground water monitoring conducted after issuance of the ROD detected elevated concentrations of Tetrachloroethene (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 half a mile upgradient from the original site.
In October 2000, 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.
EPA finalized an interim remedial action ROD in September 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.In the September 2005 final ROD, the final remedy called for continued operation of the groundwater extraction and treatment (GET) and AS/SVE systems, limited action for contaminated soils in the other source areas and chemical oxidation in the upgradient portion of the contaminant plume.
Status of Site Cleanup
Currently, the AS/SVE system is not in operation because the groundwater table is too high. The GET system is still in operation and provides treated water to the Columbus municipal water supply system. Institutional controls have been implemented at all three source areas. The City of Columbus has also instituted an ordinance which limits use of private wells within an Institutional Control Area (ICA). Regarding chemical oxidation, seven rounds of injections have been conducted in various places within the contaminant plume on a semiannual basis, starting in January 2007 through October 2009. No further chemical oxidation injections are planned at this time. Currently, EPA is in the process of reviewing all of the site data to determine what response actions will be necessary in the future. EPA is also in the process of conducting vapor intrusion sampling.
The Third Five-Year Review
Representatives of EPA and the Nebraska Department of Environmental Quality (NDEQ) inspected the site on February 17, 2010, and reviewed site information.
They found these additional actions need to be taken to ensure long-term protectiveness of the site:
- collect samples from newly installed monitoring wells and adjust ICA boundary, if necessary,
- collect samples from newly installed monitoring wells to optimize performance of the GET system,
- perform additional investigations to characterize soil contamination in the vadose zone at each of the source area properties,
- evaluate alternatives to address remaining soil and groundwater contamination, and
- collect additional vapor intrusion data and evaluate results to determine the appropriate course of action.
With the exception of vapor intrusion sampling, which is not complete and has not been included in the final assessment of the five-year review, the site remedy is currently determined to be protective of human health and the environment.
The final report, dated July 2, 2010, is available at the site information repositories and on the EPA Region 7 website at:
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||EPA Region 7 Records Center|
|2504 14th St.||901 N. Fifth St.|
|Columbus, Neb.||Kansas City, Kan.|
Questions or requests for information can be submitted to:
Community Involvement Coordinator
U.S. EPA Region 7
901 N. Fifth St.-- Kansas City, KS 66101
Toll free: (800) 223-0425