Contaminated Sediments Program

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This document was produced by Blasland, Bouck & Lee, Inc. (BBL). Any reference to a trademark name or organization does not represent an endorsement by the United States Environmental Protection Agency (USEPA), the Ohio Environmental Protection Agency (OEPA), or the City of Toledo. Additional information on this project is available from Marc Tuchman, Sediment Assessment and Remediation Team Leader, Great Lakes National Program Office, at (312) 353-1369.

Remediation of Contaminated Sediment at the Unnamed Tributary to the Ottawa River Summary Report - January 2000

Prepared for:
U.S. Environmental Protection Agency
Great Lakes National Program Office

and

Ohio Environmental Protection Agency
City of Toledo

Prepared by:
Blasland, Bouck & Lee, Inc.
6723 Towpath Road, Syracuse
New York 13214

This document summarizes the successful sediment investigation and remediation recently completed at the Unnamed Tributary to the Ottawa River located in Toledo, Ohio. As a result of several factors, including a cooperative partnership between government representatives and private industry, this site was successfully remediated in record time, culminating in the removal of more than 56,000 pounds of PCBs.

Investigating the Site

In December 1988, the Ohio Environmental Protection Agency (OEPA) initiated sediment sampling in the Ottawa River and an Unnamed Tributary in Toledo, Ohio. This initial round was followed up by two additional OEPA-led sampling events. During the investigations, polychlorinated biphenyls (PCBs) were reported in a number of sediment samples, ranging in concentration from 56 to 2,500 parts per million (ppm). The highest PCB concentration was reported in a sample collected from the Unnamed Tributary nearest a 96-inch storm sewer outfall that served as drainage for a number of nearby industrial facilities.

Although several potential sources were identified, the OEPA approached GenCorp, a former owner of one of the local industrial facilities — about remediation of the Unnamed Tributary. At the same time, a grant to remediate the site became available from the United States Environmental Protection Agency’s Great Lakes National Program Office (USEPA’s GLNPO). GenCorp subsequently entered into a partnership with the OEPA, USEPA’s GLNPO, City of Toledo, and during the selection of a remedial alternative, the United States Fish and Wildlife Service.

Removal of ~97% of the PCB mass in the Unnamed Tributary sediments;
Removal of the highest concentration of PCBs detected within soils of the low-lying area;
Extension and rerouting of the existing storm sewer pipes into a newly-constructed storm water drainage channel;
Hydraulic isolation of the Unnamed Tributary; and
Placement of 5 to 15 feet of clean fill over residual sediments.

Selecting the Site Remedy

After conducting two additional site assessments to further delineate the vertical and horizontal extent of PCBs, a Remedial Options Evaluation (ROE) Report (BBL, June 1997) was prepared, which identified the following potential technology types to address PCBs at the site: No Action, Institutional Controls, In-Situ Technologies, and Ex-Situ Technologies. Specific remedial options were assembled from each of these technology types and evaluated on the basis of the screening criteria presented by the USEPA’s Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA (USEPA, October 1988).

Based on a detailed and comparative analysis of the various alternatives, the ROE Report recommended implementation of the PCB mass removal option, which included:

Mobilization to the site began in January 1998 with remediation activities continuing though the end of June 1998. Sheetpiling and earthen berms were used to hydraulically isolate removal areas allowing excavations to proceed "in-the-dry." A total of 8,039 cubic yards of sediment and 1,653 cubic yards of soil were excavated and disposed off-site according to all applicable regulations. At the conclusion of site remediation, the area was backfilled, graded, and seeded with a variety of wetland species; sheetpiling was left in place at the former mouth of the Unnamed Tributary serving as a permanent hydraulic barrier. In all, it has been estimated that more than 56,000 pounds of PCBs were removed.

Seven key elements led to the successful and expeditious cleanup of this site, namely:

	Well-defined scope;
	Award of the U.S. Environmental Protection Agency GLNPO grant;
	Formation of a partnership between government and private industry;
	Thorough site characterization;
	Flexibility and support afforded by the City of Toledo;
	Extensive site preparation; and
	Ideal site conditions.

Contaminated Sediments Program

Monitoring Links

Remediation of Contaminated Sediment at the Unnamed Tributary to the Ottawa River Summary Report - January 2000

Investigating the Site

Selecting the Site Remedy

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