10TH STREET SITE NEBRASKA EPA ID# NED981713837 EPA Region 7 City: Columbus County: Platte County Other Names: Columbus Public Water Supply 08/02/2007 SITE DESCRIPTION The 10th Street Site is located in the south-central portion of the City of Columbus. Sampling by EPA and the state revealed the presence of volatile organic compounds (VOCs) in the municipal drinking water supply wells. Sampling of the ground water in areas surrounding the municipal well fields show VOCs in the aquifer underlying commercial and residential areas of the city as a result of dry cleaner activities. The city's water distribution system provides drinking water to approximately 20,000 people. The water supply is tested by the state and consistently meets the Safe Drinking Water Act (SDWA) limits for public water supplies. Site Responsibility: This site is being addressed through Federal actions. NPL LISTING HISTORY Proposed Date: 10/26/89 Final Date: 08/30/90 Deleted Date: THREATS AND CONTAMINANTS The ground water contaminant plum located upgradient of the municipal wells is contaminated with the VOCs tetrachloroethylene (PCE) and trichloroethylene (TCE). PCE and TCE are found in the soils at some locations and volatilize to ------- form vapors which can be trapped in soils and underground structures. People could be exposed to these contaminants through the use of water from contaminated wells and breathing air in confined spaces. At this time, the use of water from private wells should be discouraged. Air sampling that has been conducted recently does not indicate an exposure problem. CLEANUP APPROACH Response Action Status Entire Site: EPA completed a Record of Decision (ROD) document in 1995 that selected institutional controls and ground water monitoring with a contingency as the remedy for the site. The city finalized an ordinance with the goal of eliminating the use of private wells in the area of ground water contamination in October 2003. The ground water monitoring conducted pursuant to the 1995 ROD determined that additional investigation was required to delineate an additional source of contamination. Current efforts are directed toward addressing the ground water contamination and protecting the city's south wellfield. In order to address this contamination, EPA implemented a removal action in January 2000, and finalized an interim action ROD in September 2001. The air sparging/soil vapor extraction (AS/SVE) system which was constructed as part of the removal action is still in operation. The remedy required by the interim action ROD included a ground water extraction and treatment (GET) system. Construction of the GET system was completed in February 2004 and began operation in April 2004 with discharge of the treated water to the storm sewer. In May 2005, the GET system began providing treated water to the city's municipal water supply system. In the summer of 2005, extraction of the GET system was modified by the addition of a fourth extraction well. In September 2005, the EPA issued a final ROD that included continued operation of the AS/SVE and GET systems, limited action for the soils in two of the source areas, and chemical oxidation in the ground water contaminant plume. The design of the chemical oxidation remedy was completed in September 2006. EPA awarded a contract for implementation of the chemical oxidation remedy. The first round of chemical oxidation injections was completed in April 2007. A second round is planned for August 2007. Site Facts: ------- ENVIRONMENTAL PROGRESS After adding this site to the NPL, EPA performed preliminary investigations and determined that no immediate actions were required at the 10th Street Site while cleanup remedial investigation was being performed. EPA completed its fourth round of ground water sampling required by the 1995 ROD in April 1998, which indicated an additional source of contamination located about 1/2 mile upgradient from the initial site. The results of this sampling effort have been provided to the Nebraska Department of Health, the Nebraska Department of Environmental Quality and the city of Columbus, Nebraska. EPA conducted a removal action at the primary contamination source area. The removal action consists of an air sparging/soil vapor extraction (AS/SVE) system which was installed in October 2000, to address soil and ground water contamination. In addition, the city has taken one city supply well out of service and continues to blend water from the other south wellfield wells to assure that the finished water provided to the public is below the MCLs. EPA designed and constructed a ground water extraction and treatment (GET) system pursuant to an interim remedial action ROD issued in September 2001. In addition to intercepting the ground water contamination, the GET utilizes the city well taken out of service as an extraction well and provides treated water to the city's water supply system. The GET system has been in operation since April 2004. In September 2005, EPA issued a final ROD that includes continued operation of the GET and AS/SVE systems, limited action for the soils in two of the source areas, and chemical oxidation in the contaminant plume. The first round of chemical oxidation injections was completed in April 2007. The second round of injections is scheduled to began in August 2007. In September 2005, EPA completed the second Five-Year Review for the site. Based on an evaluation of available information, EPA believes the cleanup actions conducted at the site continue to be protective of human health and the environment. ------- COMMUNITY INVOLVEMENT A public availability session was held in August 2003 prior to the commencement of construction of the interim Remedial Action. EPA issued a Fact Sheet in March 2004 in regard to an investigation of a former manufactured gasification plant (fmgp) site. The March 2004 Fact Sheet included an update of activities at the 10th Street Site. The October 2004 Fact Sheet announced that EPA would sample Indoor Air. The July 2005 Fact Sheet announced the Proposed Plan and Public Meeting for OU2. A display ad ran in the Columbus Telegram announcing the Public Meeting. The Public Meeting was held 7/20/05, in order to take comments on the Proposed Plan. The ROD was signed 9/29/05. A September 2005 Fact Sheet Announced the Record of Decision Issued and also announced the Completion of the second 5-year review. Ads ran in the Columbus Telegram announcing the 5-year review completion and the ROD being issued. A treatability study was conducted as part of the remedial design. EPA issued a Fact Sheet in February 2006 that announced that the treatability study would begin. In January 2007, EPA issued a Fact Sheet announcing that the first round of chemical oxidation injections would begin. In August 2007, EPA issued a Fact Sheet announcing the second round of chemical oxidation injections would begin. ------- SITE REPOSITORY Columbus Public Library Superfund Records Center 2504 Fourteenth Street 901 N. 5th St. Columbus, NE Kansas City, KS 66101 Mail Stop SUPR (913)551-7166 REGIONAL CONTACTS SITE MANAGER: E-MAIL ADDRESS: PHONE NUMBER: COMMUNITY INVOLVEMENT COORDINATOR: PHONE NUMBER: E-MAIL ADDRESS: STATE CONTACT: PHONE NUMBER: Nancy Swyers swyers.nancy@epa.gov (913)551-7703 Beckie Himes (913)551-7253 himes.beckie@epa.gov Charlene Sundermann (402) 471-6411 MISCELLANEOUS INFORMATION STATE: CONGRESSIONAL DISTRICT: EPA ORGANIZATION: NE 07CS 03 SFD-EPA - REGION 7 MODIFICATIONS Created by: Suping Created Date: 05/28/98 03:45 PM Chang/ SUPR/R7/U SEPA/U S Last Modified by: Beckie Last Modified Date: 08/02/2007 09:31 AM Himes/R7/USEPA/US ------- ------- |