Highlights

General Comments

Comments on the 
Draft Feasibility
Study (FS)

Comments on the 
Draft Remedial
Investigation (RI)

References

Complete Report
for easy printing

About Donna Boreck

Donna Boreck's 
Resume (PDF)

Technical Assistance
Grant (TAG)

• The 1-ppm target level is not protective of human or ecologic health. An assumption is made that the remaining PCB concentrations will be managed by natural recovery -- an uncertain gamble.

• Capping in conjunction with natural recovery has been proposed as an alternative. There are a number of weaknesses in the proposal:

1.  WDNR (Technical Corner--Capping, July 2000) presented guidance on when to cap. The guidance included capping in an area where currents are no greater than 0.15 feet/sec. Average current velocities in all reaches of the river vary from 0.25 to 1.23 feet/sec.

2.  WDNR guidance included that capping should be done in areas where the maximum 100-year flood current is no greater than 0.7 feet/sec. Based on average current velocities for the different reaches of the river, the 100-year flood current may exceed the 0.7 feet/sec in all reaches of the river. Actual values for the 100-year flood current for each reach need to be determined. 

3.  The proposed capping project has been described as the …"biggest ever attempted in the U.S.". Any time an engineering design is sized larger; there are new challenges and risks associated with increasing the size and level of complexity of the design. Large scale PCB cleanup requires the best available proven technology--dredging and removal of PCBs.

4.  Capping requires long-term monitoring and maintenance. It may only take less than ten years to place the cap, but the proposed capping will require centuries of time, expense and man-hours to monitor and maintain the effectiveness of the cap -- much longer than the 10 year time frame required to dredge the river and bay.

• Many conclusions in the RI/FS are based more on modeling and less on empirical results from monitoring, data gathering, etc. Each model has its limitations. Making a decision based on model results is appropriate if the limitations are taken into account in the final decision. With what is empirically known about PCB contamination in both the river and the bay, deciding not to act, based on modeling results (i.e. leaving the PCBs in the River or Bay to natural recovery) is inappropriate.

• The method used to determine the 1-ppm extraction level is not appropriate for a contaminant like PCB. The method, similar to what is done to determine in-place reserves for mineral commodities, seems to focus more on minimizing volume of sediment extracted or cost of remediation and less on what needs to be recovered to protect human health. 

• Recovery of PCB contaminated sediment will not be 100%. Using the recovery factor from Deposit N (20%), recovery of the 1ppm sediment would be approximately 79%, not the 99% modeled for Zone 1. To maximize recovery, remediation efforts need to focus on dredging and removing as much of the deposit as possible -- not limiting recovery to sediment at a modeled 1-ppm action level.

• Quoting average values for parameters such as current velocity and wind speed gives a false sense of security in visualizing sediment transport and deposition in the river and bay. PCBs and other contaminants move in the system by events that are not 'average'.

1.  Quoted in the RI/FS, "…Based on the seasonal variations in PCB concentrations, it is estimated that more than 60% of the PCBs transported over the DePere Dam occurs during 20% of the year, when discharge is at it's greatest."

2.  The average velocity for Zone 1 is 0.25 feet per second. The velocity pegged for erosion of sediments in the Lower Fox River is 0.3 feet/sec. Below that point, sediments can be deposited. Above that point, resuspension of sediments can occur. Velocities recorded at USGS Stream Gage along the Lower Fox River revealed that actual velocities can vary significantly from the 0.25 feet/sec average and the 0.3 feet/sec erosion velocity-- hourly, daily and over periods of weeks. 

• Green Bay is not quiet water. It is a dynamic system where, based on the present footprint of PCB contamination, suspension and resuspension is ongoing. 

• Green Bay has a diverse bottom-dwelling community that will both negatively affect burial of PCB-contaminated sediment and will continue to provide a contaminated food source to fish and other wildlife. Worm species reported in Zones 2 and 3a in Green Bay can effectively churn and expose to the water column up to 6 cm of sediment on the Bay floor. 

 
• Green Bay is now a rich resource of PCBs and an independent source of contamination to both Lake Michigan, the surrounding land, and, via volatilization followed by deposition, to locations far from the bay area. Without remediation, Green Bay will be a source of PCBs for years. Ironically, if Green Bay is not remediated, it can help to re-pollute Zone 1 of the Lower Fox River, limiting efforts and wasting remediation dollars.