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Risk Assessment
Review and Analysis

Feasibility Study
Review and Analysis

Proposed Cleanup (Action) Levels for
the Fox River and
Green Bay

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2.0. Feasibility Study Review and Analysis

The Feasibility Study (FS) "developed and evaluated a range of remedial alternatives…to manage the risk associated with the presence of industrial contaminants discharged to the river." Remedial Action Objectives (RAO) for the system "lay the foundation for remedial expectations…and provide metrics to measure long-term success. RAOs for the Fox River/Green Bay remedial action plan include:

Achieve surface water quality criteria to the extent practicable;

RAOs are critically important as they provide metrics to measure long-term success of proposed remedial actions. To that end, we evaluated the proposed cleanup (or non-cleanup) options as they were presented and assessed in the FS, against the RAOs for the Fox River and Green Bay (Section 3.0 of these comments).

Remedial Action Objectives will be achieved when PCBs and other pollutants are removed or isolated so that they no longer contaminate system components including sediments and fish (among others). To that end, the Feasibility Study (FS, Chapter 5) evaluated action (cleanup) levels that determine the quantities of PCBs to be removed from the Fox River and Green Bay. Action levels, which are developed from risk-based Sediment Quality Thresholds (these comments - sections 1.5 and 1.6.3 above), "are designed to meet project expectations and RAOs." Action levels "represent safe thresholds in surface sediment that are protective of both human and ecological receptors" (FS Section 5.1, page 5-2). 

The FS evaluated an array of action levels, including those that purportedly bracket risk-based SQTs. However, risk-based SQTs are as low as 24ug/kg (hereafter - ppb) for wildlife (ecological effects) and as low as 11 ppb for human health risks, approximately an 10 times lower than the lowest action level (125 ppb) evaluated for the Fox River, and over 50 times lower than the lowest action level (500 ppb) evaluated for Green Bay (FS Section 5.5). 

Clearly, the Feasibility Study excluded evaluation of action levels that would be protective of human health and wildlife. As a result, action levels that are necessary to achieve Remedial Action Objectives were not considered in the selection of cleanup options (remedial alternatives) for the Remedial Action Plan.

Action levels as low as 125 ppb were evaluated in the FS for the Fox River. However, action levels only as low as 500 ppb were evaluated for Green Bay. The FS concludes that, at an action level of 500ppb, PCBs will not reach concentrations in Green Bay sediments after a 100-year waiting (recovery) period that will meet RAOs or be protective of human health and wildlife. Unfortunately, the FS draws this conclusion without evaluating whether action levels of 250ppb or 125ppb in Green Bay would achieve RAOs. 

Failure to evaluate action levels below 500ppb for Green Bay appears to be based on cost and technology considerations. As such, the FS inappropriately excludes action levels that are potentially protective of human health and wildlife. While it may not be feasible, because of cost or technological constraints, to achieve PCB sediment levels below 500ppb in the near term, these lower action levels should be evaluated in the FS for their efficacy in achieving RAOs and in protecting human health and wildlife in the longer term. Technology may change considerably in the next few years, and while not feasible presently, action levels below 500ppb may become feasible as technology advances, or as new cleanup alternatives emerge. As it is written presently, the FS effectively writes off cleanup options for Green Bay that may achieve RAOs in the longer term, including the 100-year period that was assessed in the FS. Therefore, the FS evaluation of cleanup options for Green Bay is fundamentally flawed and must be revised to include consideration of PCB action levels as low as 125ppb.

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