Detailed Comments on Major Project

Detailed Comments on
Little Lake Butte des Morts

Comments PDF File

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Technical Assistance
Grant (TAG)

Summary of Issues and Recommendations

• The Optimized Remedy presented in this Design Supplement represents a significant step backward from the original goals of the cleanup

• We maintain our strong opposition to capping and natural recovery in the Fox River

• The only proven remedy to contaminated sediments in rivers like the Fox is removal

• “Natural recovery” is completely unproven and undocumented as a remedy

• The placement of caps within the Fox River violates NRC guidance on capping

• Capping should be restricted only to locations where sediment removal presents a threat to the structural integrity of cultural features

• Dredging of contaminated sediments should be performed using an environmental bucket dredge rather than cutterhead hydraulic dredge whenever possible

• Strict institutional controls should be implemented during dredging such as limiting dredging activity to certain times and conditions to limit the resuspension of contaminated sediments

• If sand covers are used at all, they should be at least 6 inches thick to compensate for the effects of inevitable erosional forces that will act on the river bottom

• The schedule for monitoring efforts must be presented definitively and cannot be considered reliable in its current form

• Post-capping sampling and surveys must specifically require annual inspections in the spring to ensure the continuing effectiveness of the remedy

• The Design Supplement must include a contingency plan outlining the steps to be taken if caps prove to be ineffective or are damaged

Document Summary

This document incorporates the changes proposed in the recent Optimized Remedy regarding PCB contamination in the Fox River for OU1, the area of the Fox River directly adjacent to Lake Winnebago running through Appleton. By relying on capping, loose sand covers, and monitored natural recovery, the Optimized Remedy represents a significant step backward in efforts to reduce risks to public health and the environment from PCBs within the river. The Design Supplement is intended to provide specifics regarding cap construction, dredging methods and other activities involved in the cleanup of OU1.

General Comments

The Design Supplement for OU1 suffers from most of the same flaws as presented previously for OU2-5. The reliance on capping and sand covers is misplaced and has a high probability of failure particularly in some locations. Our position on natural recovery, sand covers, caps, and dredging remains unchanged: “natural recovery” is completely unproven and undocumented while caps and covers have no demonstrated successes in rivers like the Fox. Removal is the only proven approach to dealing with contaminated sediments in freshwater systems like the Fox River. The following comments and recommendations are intended to mitigate some of the risks we have previously identified and improve the overall cleanup.

The reliance on capping and monitored natural attenuation to contain PCBs is based on weak assumptions and no documentation. The basis of the rationale for their use is frequently contradicted by the data. While capping may provide adequate protection at some sites, it is far less suited for others. The key factor in a cap’s ability to adequately isolate contamination is the long term stability of the cap. Unfortunately, little to no long term monitoring of caps has been reported in peer reviewed literature, especially in areas that are hydrogeographically similar to the Fox River.

For this reason, the combination of dredging and capping in certain areas of the Fox River is ill advised. The Optimized Remedy would leave the most contaminated sediments in place, increasing risks to human health and wildlife in the event of a cap failure. A cap cannot be guaranteed to be 100% effective over the long term (100+ years), making the safest solution the dredging of all contaminated sediments.

There are a number of factors that contribute to the likelihood that a cap in the Fox River would be compromised. Chief among these is ice, either as frazil ice or ice jams. Frazil ice is ice that forms within the water column, and occurs most often in turbulent, shallow waters at extreme temperatures (below 0° F) (Daly, 1994). The greatest threat from frazil ice occurs when the ice attaches itself to bottom sediments, after which it is classified as “anchor ice.” The formation of anchor ice not only facilitates increased scouring, but also encourages ice jams that have an even greater impact on the riverbed. These ice formations have the potential to occur within the Fox River over one third of the year. The placement of caps within the Fox River runs against National Research Council (NRC) and EPA guidance regarding the placement of caps for this and other reasons (NRC 1997, Palermo et al 1998).

A critical component to successful capping is source control. If contaminated sediments continue to be deposited on top of a cap once it is in place, the cap is of limited effectiveness. The placement of a cap in such situations also makes future remedial actions more complicated and difficult. Cap armoring effectively prevents many types of dredging and would have to be removed prior to any remedy. Currently, there is no documented comprehensive plan to limit continued PCB loading into the Fox River. Without such a plan, placement of a cap in the Fox River violates NRC and EPA guidance (NRC 2001, Palermo et al 1998).

The equipment proposed to dredge contaminated sediments needs to be optimized to reduce resuspended sediment, spillage, and sediment left in place, collectively referred to as residuals. Section 4.2.2 proposes that 2008 dredging will be conducted using swinging ladder cutterhead dredges. Environmental bucket dredges would be much more effective and efficient. Resuspension rates from environmental bucket dredges typically run at one percent of the dredged volume or less when properly operated (NY/NJ Harbor Partnership 2003). Not only would the use of environmental bucket dredges reduce the amount of PCBs that are widely distributed through the Fox River but would also reduce the number of instances that locations will have to be re-dredged.

The implementation of institutional controls during dredging would have a similar effect. Actions such as erecting silt curtains and only dredging under specific conditions such as low wind and flow rates would also reduce the amount of residual contaminated sediment that is released (Francingues and Palermo 2005).  Dredge operators should also have documented experience working at contaminated sites and this documentation should be accessible to the public. The above are all logical steps that will greatly reduce dredging residuals as well as costs by reducing the chances that some areas will need to be re-dredged. 

The criteria for the selection of which areas will be redredged are unacceptable, as are the proposed solutions to residuals. The Design Supplement states that only areas with residual PCB concentrations over 5.0 ppm will be dredged. Residuals under this value will be covered by a layer of sand. Presumably dredging is occurring in areas where capping would not be acceptable, either because of the sheer stress from natural flow patterns or other reasons. Sand covers will not persist in such areas. Much of the dredging will occur in locations where recreational boat traffic is common. Prop wash, keels, and anchors from these vessels would easily disturb a loose sand cover. This situation could easily result in the average concentration of PCBs in some areas actually increasing after dredging. The dredge management plan needs to be revised to minimize both the resuspension and spread of contaminated sediments. If residuals with PCB concentrations over 1 ppm remain after dredging, the area must be redredged.

The data in Table 2-5 are confusing because it appears to assume that in one Sub-Area (POG2) PCB concentrations will still increase from 2.1 to 3.7 ppm after dredging even if all precautions are successful. Remedial actions that increase risks over the original concentrations are completely unacceptable. It is unclear how the removal of contaminated sediments could actually increase the average concentration of sediments in POG2, or if this increase is expected as a result of dredging residuals, a miscalculation, or some other factor. If this is not a calculation error, then it demonstrates a significant flaw in the cleanup design for this area, and the design flaw needs to be immediately addressed.

The placement of sand covers over sediments with low concentrations of PCBs is not advisable, since these covers can be quickly eroded. However, we acknowledge that this remedy has been agreed upon by the regulatory agencies and that it will eventually be implemented. To account for the inherent risks from erosion to these sand covers, all sand covers should be at least six inches in depth instead of placing three inch layers in areas with lower contamination. Three inch layers of sand could erode after even one high flow event, and scoured even more easily. Such thin sand layers though less costly in the short term would inevitably lose their effectiveness over time, particularly in locations with low deposition rates. Data within the supplemental design report support this possibility. For example, in Sub-Area F of OU1 a three inch sand cover is proposed but according to Appendix D the areas where the cover will be placed will be subject to the highest sheer stress from the combination of wind and waves. A three inch cover in this area will not persist for very long. If the sand cover is to be implemented, it should at least be thick enough to have a chance to make difference in overall PCB concentrations in the Fox River rather than being eroded away completely after one significant event. 

Long term considerations also dictate that an in-depth monitoring program be in place to regularly assess all remedies. We are pleased that there is a mandate for such a program within the design supplement, but disappointed that the design supplement provides few specifics. The lack of specifics in the Design Supplement is disconcerting, particularly given the backward step that the Optimized Remedy represents in terms of the effectiveness of the cleanup. Nothing has changed to reduce the concerns that severe weather events could compromise either the caps or the sand covers. There is ample evidence that scouring from ice or severe weather is likely, and therefore WDNR needs to monitor both the integrity of the caps as well as sediment, water column, and fish tissue concentrations of PCBs annually at minimum. The selection of the Optimized Remedy has damaged the public’s faith in WDNR’s efforts to protect public health and the environment in and around the Fox River, and the lack of specifics in the monitoring plan only reinforces this notion.

Inspections of caps should occur in the spring to evaluate if caps were impacted by ice. Severe scouring from ice that occurs in the winter months often cannot be detected until the spring (EPA 2005). Inspections can be carried out either visually with diving equipment or other means like bathymetric sonar surveys. We are aware of the conclusions in the ROD as well as in Appendix A of this design supplement that ice scour will not be an issue, but we do not share the same confidence in this opinion as the WDNR. There are simply not enough data to rule out this possibility and what data do exist imply that scouring has a high likelihood of occurring.  For more information regarding these risks please review our previous comments on the ROD for OU2-5. Annual monitoring is critical to measuring progress, understanding needed changes, and establishing confidence in WDNR’s efforts to protect the public given the very real risks involved. Even isolated instances of damage to caps or sand covers could quickly expand and compromise cleanup goals.

The Design Supplement should also include a contingency plan detailing what steps WDNR will take if a cap is compromised or fish tissue concentrations fail to drop as expected. If there is a failure in a cap there will not be months for WDNR to make a decision on how to act. Damage to the caps could quickly expand, and particularly in areas where high concentrations of PCBs will remain directly under the capping damage could result in significant releases of contaminants in a short period of time. WDNR has been made well aware of the risks associated with capping these areas and should be prepared to address them.

We remain unconvinced that the Optimized Remedy represents an effective solution to PCB contamination in the Fox River. Capping represents only a temporary solution and without a source control plan the placement of caps will only complicate inevitable future remedial actions. If the Optimized Remedy is to be implemented, simple protective steps must be implemented to make it as effective as it can possibly be. These steps include making sand covers deep enough to at least be temporarily effective, dredging in ways that minimize resuspension and residuals, and developing specific monitoring and contingency plans. Any final document that does not include these basic steps represents a failure to protect both human health and the environment from PCB contamination in the Fox River.

References

EPA. 2005. “Changes in River Sediment Conditions Attributed to Ice Jam Related Scouring.” Technology and News Trends. EPA 542-N-05-003. No.18.

Francingues, N. R., and Palermo, M. R. 2005. "Silt curtains as a dredging project management practice," DOER Technical Notes Collection (ERDC TN-DOER-E21). U.S. Army Engineer Research and Development Center, Vicksburg, MS. http://el.erdc.usace.armv.mil/dots/doer/doer.html.

NRC. 1997. Contaminated Sediments in Ports and Waterways. National Academy Press. Washington, DC.

NRC. 2001. A Risk Based Management Strategy for PCB-Contaminated Sediments. National Academy Press. Washington, DC.

NY/NJ Harbor Partnership. 2003. SSFATE Modeling of Arthur Kill Dredging—Final Report. Submitted to USACE-NYD. 

Palermo, M., Maynord, S., Miller, J., and Reible, D. 1998. "Guidance for In-Situ Subaqueous Capping of Contaminated Sediments," EPA 905-B96-004, Great Lakes National Program Office, Chicago, IL.

For more information:

 Dr. Peter deFur, Environmental Stewardship Concepts, online at http://pldefur.home.igc.org/

 Clean Water Action Council of N.E. Wis., 1270 Main St., Suite 120, Green Bay, WI 54311. 920-437-7304.   Online at http://www.FoxRiverWatch.com

 Dr. deFur's independent investigation was funded by a citizens' Technical Assistance Grant from the U.S. EPA,   provided under the federal Superfund law.
 

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