Proposed Plan for Remedial Action - Available for Comments/EPA to Hold
Railroad Avenue Superfund Site, West Des Moines, Iowa
The U.S. Environmental Protection Agency (EPA) is releasing a Proposed Plan for Remedial Action to address ground water contamination within the Northern Plume of the Railroad Avenue Superfund site in West Des Moines, Iowa. The action will be taken under the Comprehensive Environmental Response, Compensation and Liability Act, also known as the Superfund Law.
The EPA Proposed Plan recommends actions that will help to lower contaminant concentrations in contaminated ground water at this site.
EPA is asking for public comments on its Proposed Plan. The public comment period runs July 11 - August 10, 2005. Although EPA and the Iowa Department of Natural Resources (IDNR) are recommending a proposed action to address the contamination, a final decision will not be made until EPA reviews comments from the public. After the comment period closes, EPA will make a decision, which will be published in a Record of Decision (ROD). The ROD will also include a summary of EPA's responses to the comments received during the public comment period.
Ground water beneath the Railroad Avenue Superfund site is contaminated with tetrachloroethene (PCE), trichloroethylene (TCE) dicloroethylene (DCE) and vinyl chloride. EPA has divided the site into Northern Plume and Southern Plume areas. This proposed plan addresses remedial actions for the Northern Plume. A future proposed plan will address final remedial actions for the Southern Plume. EPA has not been able to identify the source of the contamination in the Northern Plume area.
MARK YOUR CALENDARS –
EPA will hold a public meeting to provide
Monday, July 25, 2005
Written comments must be postmarked by
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 investigation was conducted by IDNR. EPA completed remedial sampling in November, 2002.
The Railroad Avenue Groundwater Site was placed on the National Priorities List in September, 2002, making it eligible for cleanup under EPA's Superfund program.
The EPA completed an interim Remedial Action remedy for the West Des Moines (WDM) well field area in November 2004, that included additional treatment capabilities at the WDM water plant. The Remedial Action discussed in this Proposed Plan addresses the Northern Plume ground water contaminants that are not addressed by the interim Remedial Action.
The EPA estimates there are currently no significant risks presented by the site. However, significant potential future risks exist, based on assumptions of individual well water use from the contaminated area.
RECOMMENDED REMEDIAL ALTERNATIVES
The remedial alternatives are:
1. No Action - The National Contingency Plan requires consideration of a no further action alternative against which other alternatives can be compared.
2. Monitored Natural Attenuation - would rely on the aquifer's ability to lower contaminant concentrations through monitored natural attenuation (MNA) processes. This alternative includes ground water and surface water monitoring to confirm continued efficiency of the natural attenuation of contaminants, and institutional controls to minimize potential health risks associated with ground water contaminants still undergoing attenuation.
3. Extraction with Recovery Well/On Site Tray Aeration/Surface Water Discharge – would include extraction of contaminated ground water using recovery wells followed by on-site tray aeration treatment and discharge of the treated ground water to Gravel Pit Lake. The recovery wells would be pumped at a rate to hydraulically control the ground water flow which would provide containment of the ground water contaminant plume.
4. In-Situ Stripping Wells – two lines of in-situ stripping wells would be placed along the eastern and southern edges of the plume to treat the contaminated ground water as it migrates toward the Gravel Pit Lake and Raccoon River. It is estimated that 10 in-situ stripping wells would be required to act as a barrier between the plume and the surface water bodies.
A complete explanation of the alternatives can be found in the Focused Feasibility Study Report that is included in the Administrative Record.
We propose to select Alternative 2 as our Preferred Alternative, subject to public comment. Implementation of Alternative 2 would be performed simultaneously with the previous interim Remedial Action that included expansion of the stripping capacity at the WDM water plant. This previously implemented interim Remedial Action is intended to protect the WDM water supply from contamination, leaving the Preferred Alternative to address only the remaining contaminants that do not impact the water supply system.
The Proposed Plan and other site-related documents provide details of the nature and extent of contamination and the work that has been completed at the site. These documents are part of the Administrative Record, available during regular business hours at the following locations:
Wes Des Moines Public Library
4000 George M. Mills Civic Parkway
West Des Moines, Iowa
EPA Region 7 Records Center
901 N. 5th Street
Kansas City, Kansas
If you have questions or need additional information concerning the public meeting or the Railroad Avenue site, please contact:
Office of External Programs
U.S. EPA Region 7
901 N. 5th Street
Kansas City, KS 66101
Phone: 913-551-7003 or
Toll Free: 1-800-223-0425