News

Background

PCB Contamination

• What are PCBs?
• PCBs in the Fox River
• PCBs and Health

Cleanup Activities

• Overview
• OU 1
• Progress Reports
• OUs 2-5
• Demonstration Projects
• Cleanup Alternatives
• Capping
• Landfilling
• Vitrification

Natural Resources Restoration (NRDA)

• Restoration Projects
• Trustee Council

How did they do that?

Public Involvement

Reports & Documents

• Reports & Documents
• Database [exit DNR]

Contacts & Links

Fox River Current [exit DNR]

Fox River Project

A Mass-Balance Approach for Assessing PCB Movement During Remediation of a PCB-Contaminated Deposit on the Fox River, Wisconsin

U.S. Geological Survey

The U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources (WDNR), collected water samples during the September 1-December 15, 1999 removal of sediment contaminated with polychlorinated biphenyls (PCBs) from a reach of the Lower Fox River designated Sediment Management Unit 56/57 (SMU56/57). Results of analyses of the samples, along with monitoring activities of several other organizations, were used to delineate and compare PCB mass pathways during the cleanup effort.

Water quality and aquatic life in the Lower Fox River, which flows from Lake Winnebago to Green Bay, have been affected by contaminants that have accumulated in streambed sediments over the last several decades. The WDNR has determined that contaminants released from Fox River sediment deposits cause exceedances of State water-quality standards and necessitate fish-consumption advisories. From the perspective of human health and ecological risk, polychlorinated biphenyls (PCBs) and mercury are the principal contaminants of concern. Sampling has confirmed that sediment-associated PCBs and mercury are accumulating within the aquatic food chain and are actively being transported within the river and out into Green Bay and Lake Michigan (Brazner and DeVita, 1998).

The SMU 56/57 remediation project was a joint effort between the State of Wisconsin and the Fox River Group (FRG), a coalition of paper companies. A primary purpose of the project was to remove PCB-contaminated sediment by dredging and thereby generate information relevant to the effectiveness of large-scale dredging and disposal of the sediments (in this case, 7-11 million cubic yards) from the Lower Fox River (ThermoRetec Consulting Corp., 1999; Blasland, Bouch, and Lee, Inc., 1999; Montgomery Watson, 2000). A hydraulic dredge was used to pipe a sediment slurry from the river bottom to a settling basin; the onshore operation consisted of filter-pressing the slurry, filtering the liquid effluent and returning it to the stream, and trucking away the solids. In support of the sampling plan designed by the FRG and WDNR, a mass-balance approach (a combined examination of concentration and flow) was used to determine the effectiveness of dredging in removing the PCBs from the river environment.

Read the Entire Report (227k PDF File)