EPA Region 7 09/09/2008 City: County: Polk County Southwest of downtown Des Moines Other Names: Tuttle Street Landfill Des Moines Vocational School Dichem Dico Company SITE DESCRIPTION The Des Moines TCE site is an area of contaminated ground water located southwest of downtown Des Moines, in the flood plain of the Raccoon River. The surrounding area is industrial and commercial, with some recreational parklands. The city's public water supply, which serves approximately 260,000 people, was discovered to be contaminated with trichloroethylene (TCE) in 1976. The contamination was entering the water supply through the city's ground water source. The Dico Company, who used and disposed of solvent wastes containing TCE on their property through early 1979, was determined to be a potential source of the contamination. In 1984, the Des Moines Water Works stopped using the contaminated portion of the ground water supply. In 1986, EPA ordered Dico to undertake the Agency's selected remedy to protect the city's public water supply. During cleanup activities, another plume (the North plume) of contaminated ground water was discovered as being drawn into the ground water extraction system. An investigation was subsequently initiated to address the contamination apparently originating to the north and west of the Dico property. In addition, investigations on Dico's property revealed that past herbicide and pesticide formulation activities had left contamination in several Dico buildings and adjacent soils. Site Responsibility: This site is being addressed through Federal, state, and potentially responsible parties' actions. The state and DICO are currently conducting a program to monitor the contamination in the ground water. DES MOINES TCE IOWA EPA ID# IAD980687933 NPL LISTING HISTORY Proposed Date: 12/30/82 Final Date: 09/08/83 Deleted Date: ------- THREATS AND CONTAMINANTS The ground water and soil are contaminated with volatile organic compounds (VOCs), including tetrachloroethylene, TCE, and vinyl chloride, and pesticides and herbicides from former industrial operations and waste disposal practices. Accidentally ingesting or coming into direct contact with the contaminants poses a health risk. CLEANUP APPROACH Response Action Status Initial Actions: Dico has cleaned several buildings on their property that were previously used to formulate and store pesticide and herbicide products. In addition, Dico has covered a large portion of their property with an asphalt cap to address the threat presented by the surface soil contamination. A group of parties potentially responsible for pesticide and herbicide contamination has excavated and disposed of contaminated soils from drainage areas on and adjacent to Dico property. Ground water: The remedy for the protection of the Des Moines water supply features: isolating the northernmost section of the public water supply system; collecting contaminated ground water with extraction wells; treating the ground water with an air stripper to remove contaminants; discharging the treated water to the Raccoon River; and operating the extraction wells until water collected from all monitoring wells meets EPA drinking water standards for four consecutive months. Dico, under EPA oversight, designed and built the ground water extraction and treatment system, which included seven extraction wells and an air stripping system. Cleanup activities began in December, 1987. Dico has operated and maintained the ground water treatment system since 1987. Source Control: In 1989, Dico began an intensive study of the sources of the pollution on its property. This investigation showed that contamination by VOCs and pesticides is of significant concern at the site. The studies have identified various source areas as well as potential remedies. The initial removal actions discussed above have addressed many of the health concerns associated with the source areas. EPA's selected remedial action, as documented in the December, 1996 Record of Decision, calls for continued maintenance of the three removal actions and land use restrictions to maintain an industrial land use. North Plume: In 1988, EPA began investigating the potential sources of contaminated ground water being drawn into the Dico ground water extraction and treatment system. EPA installed additional monitoring wells to the north and west of the Raccoon River near the Fleur Drive Bridge and north to about 25th and High Street. The wells have been monitored to determine the as & '/YV / ------- extent of contamination and its source(s), and to warn of any approaching danger to the public water supply. This investigation was completed in the spring of 1992, and EPA concluded that no further action is warranted; the existing ground water extraction and treatment system will capture and clean up the contaminated ground water plume. Site Facts: Facts: In 1986, EPA issued an Administrative Order requiring Dico to design, build, and operate a ground water extraction system. Dico signed an Administrative Order on Consent with EPA in August 1989, to conduct a study of how to control the potential sources of contamination at its property. A Unilateral Administrative Order (UAO) was issued to Dico in March 1994, calling for a removal action to address threats inside several on-site buildings. A second UAO was issued to Dico in June 1994, calling for a removal action to reduce threats posed by on-site soils. A group of additional potentially responsible parties identified in association with the pesticide and herbicide contamination signed an AOC in December 1995, requiring the parties to conduct a removal action to address threats posed by contaminated soil in drainage areas at the site. ------- ENVIRONMENTAL PROGRESS Ground water cleanup at the Des Moines TCE site including a ground water monitoring program is currently underway which, along with the three initial removal actions, has reduced the potential for exposure to hazardous substances found at the site. In 1994, pesticide- and herbicide-contaminated dust were removed from several on-site buildings, and the interior surfaces were sealed to prevent exposure to any remaining pesticide and herbicide residues, and polychlorinated biphenyls (PCBs) found in building insulation. In addition, exposure to pesticide-contaminated soils has been eliminated by capping a large portion of the Dico property and removing contaminated soils from the site. Long term actions will include operation and maintenance activities necessary to ensure the continued protectiveness of the ground water extraction and treatment system and the asphalt cap. EPA completed the fourth five-year review for the site in February 2008, which concluded that the actions taken at the site remain protective. During the fourth five-year review, EPA discovered that three of the onsite buildings involved in the 1994 removal action had been dismantled. EPA is working with the site owner and other parties involved in order to assure proper disposal of building materials. The fourth Five-Year Review Report is available in the site information repository. COMMUNITY INVOLVEMENT 8/02 - Fact Sheet announcing start of 3rd 5-year review. 6/03 - Fact Sheet announcing completion of 3rd 5-year review. Display ad in the Des Moines Register, 6/8/03. 8/07 - Fact Sheet announcing start of 4th 5-year review. Display ad in the Des Moines Register, 8/16/07. 7/08 - Fact Sheet announcing the availability of the 4th 5-year review report. Display ad in the Des Moines Register, 7/18/08. ------- SITE REPOSITORY Des Moines City Library 1000 Grand Avenue Des Moines, IA 50308 Superfund Records Center 901 N. 5th St. 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: Mary Peterson peterson.mary@epa.gov. (913)551-7882 Beckie Himes (913)551-7253 himes.beckie@epa.gov Bob Drustrup (515)281-8900 MISCELLANEOUS INFORMATION STATE: CONGRESSIONAL DISTRICT: EPA ORGANIZATION: IA 0725 03 SFD-IANE/SUPR MODIFICATIONS Created by: Karla Created Date: Asberry/SUPRFUND/R7/US EPA/US Last Modified by: Fritz Hirter/R7/USEPA/US Last Modified Date: 10/16/97 11:17 AM 09/09/2008 01:09 PM ------- |