The Railroad Avenue Site is located in West Des Moines, IA (a suburb of Des Moines, IA) in southwest Polk County and south central IA. The Railroad Avenue Site consists of the West Des Moines water treatment plant well field, the areas of observed groundwater contamination, and the potential source areas of the contamination. The West Des Moines well field contains the 25 West Des Moines municipal water supply wells (WDMW) which historically have supplied or currently supply water to the West Des Moines water treatment plant.
Current Site Status and Cleanup Actions to Date
- The site was first identified in 1993, when a routine water distribution sample showed contamination. EPA was made aware of the site in 1996, after a site inspection was conducted by Iowa Department of Natural Resources (IDNR). The site is contaminated with tetrachloroethene (PCE), tricloroethylene (TCE) dicloroethylene (DCE) and vinyl chloride.
- EPA's Remedial Investigation (RI) was completed in November 2002. The Railroad Avenue Groundwater Site was placed on the National Priorities List (NPL) in December 2002, making it eligible for cleanup under EPA's Superfund program.
- Two separate source areas and their respective contaminant plumes have been identified at the site: the Southern Plume and the Northern Plume.
- The Southern Plume is located south of the West Des Moines Water Works and northwest of wells WDMW-19, -20, and -21, where a release of TCE is reported to have occurred.
- Further investigation and remediation of the Southern Plume was performed by the Potentially Responsible Parties (PRP) with IDNR as the lead agency. The PRP initiated a Removal Action to construct aerators at the WDM Water Works on October 18, 2004.
- The Northern Plume work is being conducted as a fund-lead, with EPA as the lead agency. The RI found that there is potential for the western portion of the Northern Plume to adversely affect nearby municipal water supply wells; thus, EPA has determined that a focused Feasibility Study (FS) should be conducted to address the contaminated groundwater in closer proximity to these wells.
- A Record of Decision (ROD) was approved on September 26, 2003 for the Northern Plume area near the municipal water supply wells. This remedy includes use of the aerators being constructed at the Water Works by the PRP for the Southern Plume. When the aerators are constructed and tested, the contaminated Northern Plume wells will begin pumping, using the aerators to treat volatile organic contaminants. After a period of operation and testing, remedial action for the remaining portion of the Northern Plume will be pursued.
- Currently, five municipal wells have been taken offline as a result of the chlorinated volatile organic compound (VOC) contamination. All wells are used only periodically, depending upon seasonal water demand.
Current Funding Status
- Other than RI/FS funds spent at the site, the only Remedial Design/Remedial Action (RD/RA) dollars spent to date is the RA money obligated in September 2004 ($300,000) to provide for Long Term Response Action (LTRA) at the site. This money was included in a CA with the West Des Moines Water Works, which will operate and maintain the aerators under the LTRA.
- The original request for $1 million for this work and construction at these portions of the site was unnecessary, due in part to the response action of the PRP to install aerators at the Water Works. Accordingly, the regional request was reduced to $300,000 - the amount required until selection of an RA for the remainder of the Northern Plume.
For more information on the projects at this site, please read the Railroad Avenue Groundwater Contamination Fact Sheet (PDF) (33 K, 3 pp) on the Region 7 Superfund Web site.
- The Potentially Responsible Parties (PRP) response action at the Southern Plume has been leveraged to provide treatment for Northern Plume contamination at no additional capital cost and very low Long Term Response Action (LTRA) costs.
- This action has allowed West Des Moines to regain use of several municipal water supply wells and provide additional levels of protection for any future contamination of the city water supply.
- EPA and the WDM Water Works have entered into a Cooperative Agreement (CA) under which the Water Works will receive funding to conduct the LTRA at the site B this in lieu of EPA hiring an outside contractor to perform the work. This should lead to more efficient use of funds and allow Water Works to conduct the work.