A.14 Fox River and Green Bay, WI 2002

A.14.1 Summary

Environment:	Freshwater
Scale:	Full
Contaminants of Concern:	PCBs, 54 ppm avg., metals (mercury), PAHs
Final Remedy:	Hydraulic auger used to dredge material. Material taken to Fort James landfill, six miles away. Sediment isolated in separate cell and monitored for leachate for life of landfill.

A.14.2 Site Description

Year: 2002

Project 1 SMU 56/57

Water Depth: 2–14 ft

Target Volume: 92,000 yd³

Actual Volume Removed: 81,816 yd³ (9 acres)

A.14.3 Remedial Objectives

• SWAC, Upper four inches, PCB concentration of 1 ppm or less.
• SWAC, PCB concentration of 10 ppm or less, with six-inch sand layer backfill.

A.14.4 Remedial Approach

Hydraulic auger for dredging. Dredge replaced several times due to lack of effectiveness. Several different dredges used, and two dredging passes were required (1999 and 2000).

Silt curtains used. Several times, perimeter silt curtains were dislodged or torn by currents. Curtains required significant maintenance throughout; therefore sheet piling placed at area corners for stable anchoring.

The entire dredge site was backfilled with a 9–12 inch sand layer.

A.14.5 Monitoring

Post dredging results were as follows:

• 11 of 28 samples <1 ppm
• 24 of 28 samples <4 ppm
• Average, 2.2 ppm with range of ND-9.5 ppm

A.14.6 References

Fox River Cleanup Group. http://foxrivercleanup.com/documents/.

USEPA. First Five-Year Review Report for Fox River NRDA/PCB Releases Site. July 2009 http://www.epa.gov/superfund/sites/fiveyear/f2009050002959.pdf.

Major Contaminated Sediment Sites Database; Sept. 2004 as updated 2008. http://www.smwg.org/MCSS_Database/MCSS_Database_Docs.html.

Publication Date: August 2014