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Fact Sheet 9

Fact Sheet #9

September 2003

DePue, Illinois

South Ditch

What is the Illinois EPA's decision about the remedy for the South Ditch unnatural sediments?

The Illinois Environmental Protection Agency (Illinois EPA or Agency) has chosen removal of the South Ditch unnatural sediments and on-site storage of the sediment in an interim containment cell. The U. S. Environmental Protection Agency (U.S. EPA) concurs with this decision. The agencies signed a record of decision in September 2003 to document this decision. The Illinois EPA has written a responsiveness summary that summarizes the comments received during the comment period and the Illinois EPA and U.S. EPA's responses to these comments. This summary, as well as the South Ditch Record of Decision, is in the Selby Township Library in DePue for public review.

What were the events leading to this decision?

May 1998. The PRPs submitted a proposal to remedy the South Ditch sediments by leaving them in place and constructing a cap over the sediment.

Illinois EPA rejected this proposal for several reasons including the fact it did not comply with state and federal regulations.

February 2001. At Illinois EPA request, the PRPs submitted a revision of the initial plan as a presumptive remedy. In this revision, the unnatural sediments would be dredged from the South Ditch and placed in an on-site interim containment cell. The PRPs assumed that a waiver of water pollution control laws and regulations would be necessary and the Illinois EPA had the authority and would support that waiver. The Illinois EPA does not have this authority at this time.

September 9, 2002. The Illinois EPA issued a proposed plan to remove the unnatural sediments from the South Ditch and deposit them in an on-site interim containment cell. This proposed plan required compliance with federal and state water pollution control laws and regulations or validation that relief from these laws and regulations is necessary. The Agency opened a public comment period on the proposal and other studied alternatives. At the PRPs' request, the Illinois EPA extended the closing date of the comment period from November 12 to December 20, 2002.

October 9, 2002. The Illinois EPA held a public hearing to receive oral comments on the proposed plan and other studied alternatives.

Who submitted comments to the Illinois EPA during the public comment period?

The Illinois EPA received oral comments from citizens and Viacom International Inc. at the public hearing. The DePue Village Board of Trustees and the Bureau County Board submitted written resolutions supporting removal of the South Ditch sediments and hauling the sediments to a permitted off-site landfill. Two citizens supported this same position with written comments. One citizen submitted written comments on different issues, and the potentially responsible parties 1 (PRPs) submitted extensive legal and technical written comments.

Why did the Illinois EPA choose removal of the sediments and on-site storage in an interim containment cell?

After carefully considering all questions and comments, the Illinois EPA, with U.S. EPA concurrence, chose the remedy proposed in the September 2002 proposed plan for a number of reasons including the following:

  • The remedy meets all federal and state laws and requirements.
  • An on-site containment cell will be as safe as an off-site landfill permitted for similar material, because they both must meet similar standards.
  • The nearest landfill suitable for the South Ditch sediments is about 60 miles from DePue. Hauling the sediment 60 miles, compared to one mile from the ditch to an on-site interim containment cell, is an increased safety hazard. The greater transportation distance increases the risk of accident and accidental release of contaminants to the environment.
  • The 1995 Interim Consent Decree signed by the PRPs and the State of Illinois requires that all investigations and remedies complement one another if possible. The Interim Consent Decree presumes that the most likely remedy for the slag pile is on-site closure because of its large volume. Selection of any remedy will go through the standard remedy selection process including submitting a proposed plan to the public for comment.
  • By maintaining the South Ditch sediments in an on-site containment cell, the sediments remain a candidate for technologies such as metals recovery. This alternative and other resource recovery alternatives may prove viable during the remedy selection process for other units such as the primary zinc slag pile.
  • The South Ditch remedy is only an interim remedy, so the final fate of the South Ditch sediments will be made when a decision is made about all the on-site contamination. The South Ditch sediment is only about 0.4 percent of the total on-site contaminated materials 2, so its relatively small volume will have little or no influence on the final decision about the site remedy.

What are the next steps for remedying the South Ditch unnatural sediments?

Beginning this fall and finishing in the year 2004, the PRPs will construct the South Ditch remedy designated in the Record of Decision. Completion in 2004 is dependent upon normal seasonal lake and river levels that affect surface water levels in the South Ditch.

1 The PRPs for this site are Horsehead Industries, Inc., Exxon Mobil Corporation and Viacom International Inc.

2 The volume of South Ditch sediments is estimated to be 7,900 cubic yards compared to an estimated 763,000 cubic yards of slag in the slag pile. Also, the lithopone ridges on site contain an estimated 71,000 cubic yards of material and other on-site waste and slag is estimated at about 1,021,000 cubic yards.

Overall Remedial Investigation of the Plant Property

What is the status of the overall investigation of the plant property?

The following are actions accomplished in the last two years:

December 2000. The PRPs for the site completed the fieldwork for the Phase I investigation of the plant property.

June 2002. The PRPs submitted a draft three-inch report describing and interpreting sample results. This report is called a remedial investigation (RI) report.

February 2003. The Illinois EPA and its contractor thoroughly reviewed this document and returned substantial comments to the PRPs. One of Illinois EPA's more significant comments was that the PRPs used an inappropriate method to determine which chemicals on the site are of concern. The PRPs will soon be submitting alternative methods for determining chemicals of concern and these will be reviewed by the Illinois EPA.

What are the next steps in the remedial investigation of the plant property?

The following are anticipated next steps for the plant property investigation.

  • This winter, the Illinois EPA anticipates that the PRPs will submit a revised copy of the RI report that will meet Agency approval. At that time, the Agency will summarize the report in a fact sheet to be distributed to the project mailing list and place the full report in the project repository located in the Selby Township Library in DePue.
  • The Illinois EPA and the PRPs will identify data gaps. Data gaps are questions that need to be answered before the remedy is designed. For example, if present data showed contamination at 10 feet and no samples were collected below 10 feet, then an unanswered question would be, "Is contamination present at depths greater than 10 feet?"
  • If there are data gaps, the PRPs will develop a Phase II work plan to gather information to fill these data gaps.
  • After the Illinois EPA approves the Phase II work plan, the PRPs will conduct the fieldwork described in the approved work plan.
  • The PRPs will repeat this process until they have gathered the information necessary to develop a study of alternatives (feasibility study or FS). They will then prepare an FS, which must be approved by the Illinois EPA.
  • The Illinois EPA will designate one of the alternatives studied in the approved FS as a proposed plan and submit the FS and the proposed plan to the public for comment.
  • After considering public comments, the Illinois EPA will choose a remedy for the plant property. The Illinois EPA will document this remedy in a record of decision.
  • The Illinois EPA and PRPs will negotiate a second consent decree. If negotiations are successful, the PRPs will agree to construct the remedy designated in the record of decision.

Lake DePue

What is the status of the Lake DePue investigation?

The PRPs are preparing a work plan for the lake and the southeast area. See the map on the first page. When the PRPs submit a work plan that Illinois EPA can approve, the PRPs will begin the fieldwork described in the work plan.

Water Treatment Plant

What is the status of the water treatment plant?

The water treatment system continues to collect groundwater (water beneath the ground) and surface runoff from the plant property and remove high levels of metals before the water is discharged into the Illinois River. The water treatment plant is operating as expected. During heavy rainfall, there have been several bypasses of the system. The system cannot handle the volume of water generated during these unusual events. In almost six years of operation, however, there is no indication that the more heavily contaminated water from the slag pile area bypassed the treatment system. Instead, the water that bypasses the system during these storm events is water from the North Ditch, which has significantly lower concentrations of metals. The improvements to the collection system and management of uncontaminated water have significantly reduced the frequency of bypasses.

July 2002. The PRPs submitted a proposal to the Illinois EPA for additional surface water studies. These studies ultimately will lead to diversion of additional clean water around the site, enhanced storm water retention or other improvements to storm water management.

August 2002. The Illinois EPA returned written comments on the proposal to the PRPs.

December 2002. The PRPs submitted a revised proposal in response to Illinois EPA concerns.

February 2003. The Illinois EPA returned comments on the PRPs' December 2002 proposal. One Illinois EPA comment was that the PRPs must "present a new list of analytical parameters 3 and a rational for each sample point where a reduced parameter list is proposed."

July 2003. The PRPs submitted a revised plan and it is under review at this time.

Next steps. After the PRPs submit a plan for additional surface water studies that the Illinois EPA can approve, the PRPs will conduct the fieldwork to implement the plan.

Gypsum Stack

What is the status of work on the gypsum stack?

The PRPs are ahead of schedule in regrading, seeding and dewatering the gypsum stack located north of Route 29. The PRPs anticipate completing the regrading and seeding of the gypsum stack by late 2004. The PRPs have completed excavation of phosphogypsum from the Clearwater Pond (the pond at the base of the stack that is visible from Highway 29) and have placed it in the southwestern section on top of the stack. Rebuilding or reconstruction of the Clearwater Pond is expected to be completed this fall.

3Parameters are variable characteristics. In this case, the parameters or variable characteristics of water samples include the type and amount of chemicals and the amount of total dissolved solids. Samples are only analyzed for the important characteristics (a list of parameters) for a given situation. Sometimes there is disagreement about which parameters are important.

What are the next steps for work on the gypsum stack?

The final remaining pond in the southeast quadrant of the phosphogypsum stack will be emptied this fall and the southeast quadrant will be regraded, seeded and vegetated during 2004. The PRPs also are proceeding with a hydrogeological study that will complete characterization of subsurface conditions and groundwater quality. The data from the hydrogeologic study will help guide final closure options and will be used to implement a long-term monitoring program.

Off-Site Soil--Including Residential Soil

What about off-site soil sampling including sampling of residential soil?

This fall, the Illinois EPA will meet with the PRPs to begin planning for off-site soil sampling. In 1992, the Illinois EPA detected elevated levels of metals in 20 residential soil samples. The purpose of future sampling is to determine if the elevated levels pose a health threat to residents exposed over the long term. The Illinois Department of Public Health (IDPH) evaluated the 1992 soil samples and concluded that metals concentrations in these samples did not pose a risk over the short term. In the meantime, IDPH recommended that residents take common sense precautions to limit their exposure to soil. These precautions included not allowing children to eat outside, washing hands before eating and keeping windows closed during windy days when dirt could blow into the house.

Land Use Committee

What is the Land Use Committee?

The Village of DePue was awarded a grant of services in July of 2002 by the U. S. EPA. The purpose of the grant was to assist the community in developing a set of future land use recommendations for the New Jersey Zinc/Mobil Chemical Superfund site. These recommendations are intended to provide guidance to the Illinois EPA and the U.S. EPA on the community’s reuse goals for the site. The consultant team guiding this process, E2 Inc., has helped assemble a committee consisting of a diverse group of community members as well as the PRPs since the PRPs are major landowners. This committee, referred to as the Land Use Committee, met in late March and again in late May to discuss the community’s preferences for reuse of the Superfund site. A number of community interests and ideas for the site’s reuse were touched on at the first meeting, including:

  • the importance of Lake DePue as a tourist attraction and an ecological resource,
  • the need for new economic growth in the Village and
  • the potential for expanding recreational opportunities in DePue.

Based on this discussion, E2 Inc. conducted and presented research to the Land Use Committee on the potential economic benefits of marketing the Village as an ecotourism destination with hiking, biking and wildlife viewing opportunities. The consultant team also presented the committee members with a variety of resources that can aid the Village in marketing, designing and funding the development of recreational facilities in the community. E2 Inc. is currently crafting a Draft Conceptual Reuse Plan for the site based on suggestions and issues raised at the two meetings and will present this plan to Village of DePue officials for review in the coming months before delivering the final plan to the U.S. EPA and Illinois EPA.

For More information


You may contact Kurt Neibergall Illinois EPA Office of Community Relations (217) 785-3819, or Rich Lange, Illinois EPA Project Manager (815) 447-2125, at 1021 North Grand Ave. East; P.O. Box 19276, Springfield, IL 62794-9276.

Illinois EPA Web Page:

Project fact sheets are also available on the Illinois EPA Web Page:


The Illinois EPA has placed project documents in the Selby Township Library in DePue for public review. Please call the library for hours (815/447-2660).

Administrative Record File:

The administrative record file contains all documents upon which project decisions are based. This file is located in the Springfield office of the Illinois EPA. Call for an appointment at 217/782-9878. A copy of the administrative record file index is located in the project repository in the Selby Township Library in DePue. The documents listed in this index are included in the repository documents.

PRP Contact:

The PRP contact is Jim Frank, Frank and West, 7226 N. State Route 29, Springfield, IL 62707, telephone number 217/487 7687.