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Fact Sheet
July 2007
EPA Announces Explanation of Significant Differences, Aluminum Company of America Site, Riverdale, Iowa
INTRODUCTION
The U.S. Environmental Protection Agency Region 7 announces the issuance of an Explanation of Significant Differences (ESD) for the Aluminum Company of America (Alcoa) Site, located in Riverdale, Iowa. The ESD describes significant differences to the original remedy that was selected for the Alcoa Site, as documented in the September 2004 Record of Decision (ROD).
BACKGROUND
The Alcoa facility is an active aluminum sheet and plate rolling mill that has been in operation since 1948. Aluminum production and waste management activities have resulted in ground water contamination at the Alcoa Site. The primary contaminants of concern are classified as volatile organic compounds (VOCs). The VOCs include compounds associated with degreasing solvents used to clean the aluminum prior to entering the finishing process.
Specifically, the ESD clarifies the compounds and ground water performance standards that will be used in the ground water monitoring program. The ESD also clarifies the compounds and associated discharge limits that will be used as performance standards for the water discharged to the Mississippi River after it has been treated by the air stripping treatment system (i.e., the effluent from the air stripper).
The new performance standards identified in the ESD will not fundamentally alter the ground water remedy specified in the ROD. EPA is negotiating an agreement with Alcoa that includes implementation of the ground water remedy by Alcoa with EPA oversight. The major components of the ground water remedy at the Alcoa Site include:
. Ongoing operation of a ground water containment, extraction, and treatment system;
. Ground water monitoring and effluent monitoring; and
. Institutional controls to limit exposure to contaminated ground water.
PUBLIC COMMENT PERIOD
EPA encourages the public to review the ESD and other site-related documents at the information repositories during normal business hours. EPA will take written comments on the ESD through August 10, 2007. The ESD and other site-related documents are available at the following locations:
Bettendorf Public Library
2950 Learning Campus Drive
Bettendorf, Iowa
EPA Region 7 Office
901 N. 5th Street
Kansas City, Kansas
Written comments on the ESD should be sent to EPA at the address listed below:
Community Involvement Coordinator
Office of External Programs
U.S. EPA Region 7
901 N. 5th Street
Kansas City, Kansas 66101
Fax: 913-551-7066
Email: himes.beckie@epa.gov
ADDITIONAL INFORMATION
For more information on the site, please call the EPA Region 7 toll-free number, 800-223-0425, and ask for Beckie Himes.