Second Five-Year Review Completed, Mid-America Tanning Superfund Site, Sergeant Bluff, Woodbury County, Iowa
The U.S. Environmental Protection Agency (EPA) conducts regular five-year checkups, called five-year reviews, on Superfund sites where cleanups have been completed. These reviews are required by the Superfund law [42 U.S.C. Section 9621(c)]. EPA Region 7 and the Iowa Department of Natural Resources (IDNR) have completed the second five-year review of the Mid-America Tanning Superfund site near Sergeant Bluff, Iowa. The site is located in Woodbury County, Iowa, approximately 10 miles south of Sioux City and about 6 miles south of Sergeant Bluff.
Before the cleanups began, the site posed a potential threat to public health through direct contact with contaminated soils, building surfaces, pond contents, and through potential migration of chromium into the surrounding ground water.
The site is a former leather tannery which operated from 1970 to 1989. Wastewater that contained chromium was discharged to on-site ponds. Chromium contaminated sludge accumulated at the bottom of the ponds and was placed in trenches on-site. When operations ceased in 1989, there was an estimated 5,000 gallons of chromium tanning solution on-site along with 525 gallons of sulfuric acid left over from the tanning process.
In 1990, EPA initiated a cleanup which included:
- Excavating and stockpiling contaminated sludge from the on-site burial trenches.
- Treating chromium tanning solutions.
- Neutralizing sulfuric acids.
- Initial decontamination of the buildings.
In 1994, EPA issued an Administrative Order to Foxley Cattle Company, a Potentially Responsible Party (PRP), to perform a second cleanup to address re-contamination concerns. The cleanup performed by Foxley was completed in 1995 and consisted of:
- Decontaminating buildings.
- Removing and disposing drummed wastes.
- Securing the site buildings and man-holes.
In 1999, EPA implemented the remedial action at the site. The work included:
- Excavating contaminated soil, sediment, and sludge and then placing those materials in landfill areas.
- Treating wastewater in several site reservoirs.
- Installing floating covers on existing ponds.
- Steam cleaning selected site facilities.
- Installing chain link fencing.
Monitoring conducted at this time showed no contamination of the ground water.
In 2005, EPA conducted an additional cleanup at the site in response to a release. There was an emergency response followed by a permanent action which was completed in 2007. The long term remedy included:
- Removing the floating covers on existing ponds.
- Solidifying sludge within ponds.
- Installing a soil cover and plants.
The site was placed on the Iowa Registry of Hazardous Waste or Hazardous Substance Disposal Sites.
A notice of disposal of hazardous substances at the site was placed on the property deed.
The Five-Year Review
During the five-year review, EPA, the Iowa Department of Natural Resources, and the Army Corps of Engineers reviewed site operations and maintenance records, monitoring data, and other reports and inspected the remedy. A technical assessment was performed to determine if the remedies are still protective of human health. The assessment sought to ensure targeted cleanup levels continue to be protective of human health and the environment and that state and federal requirements continue to be met. An evaluation of progress made since the last five-year review was also performed. Subsequently, a Five-Year Review Report was prepared to document the result of the review.
Results of the Five-Year Review
Based on the documents reviewed and the site inspection conducted on April 30, 2008, the remedies are functioning as intended.
The 2007 action has served to enhance the protectiveness of the remedy by providing a more stable cover over waste materials of former aeration lagoons. State and federal requirements continue to be met even though the changes to the Water Quality Standards for Iowa and the maximum contaminant level (MCL) for arsenic have become five times stricter since the last five-year review.
All threats at the site have been addressed through solidification of wastes on-site and institutional controls which prevent unrestricted use of the site. This review found the remedies at the site continue to be protective of human health and the environment.
The five-year review report and the complete site administrative record are available at the following locations during normal business hours:
401 Fourth St.
Sergeant Bluff, Iowa
EPA Records Center
901 N. Fifth St.
Kansas City, Kansas
Questions or requests for information can be submitted to:
Community Involvement Coordinator
EPA Region 7
901 N. Fifth St.
Kansas City, KS 66101
Toll free: (800) 223-0425