goals (PRGs)1 for use in making remedial decisions at the site. Many of the actions included in the proposed remedy (as documented in the ROD) were specifically intended to reduce or eliminate risks to ecologic resources in the basin.

In the statement of task, the committee is directed to assess the adequacy and application of EPA’s Superfund guidance in terms of currently available scientific and technical knowledge and best practices. Specifically, with regard to the Coeur d’Alene River basin site, the committee is to consider the scientific and technical aspects of the following:

  • Assessing the ecologic risk from waste-site contaminants in the context of multiple stressors.

  • The necessary data and appropriate analyses to estimate the ecologic risks attributable to waste-site contaminants—specifically, how well these analyses were applied to estimate the risks, including the effects of lead on migratory fowl.

  • Whether risks attributable to sources other than mining and smelting activities were adequately analyzed.

In addressing the charge, this chapter reviews the Coeur d’Alene River basin ERA with respect to the following criteria:

  • Consistency with agency guidance for ERAs

  • Consistency with best scientific practice in ERA

  • Validity of conclusions

In addition, the chapter addresses the extent to which the proposed remedy is consistent with the conclusions of the ERA and the likelihood that the selected remedy will significantly improve ecologic conditions in the Coeur d’Alene River basin.

In performing its review, the committee found it neither necessary nor appropriate to evaluate all of the underlying scientific studies or to identify all of the aspects of the ERA that could have been improved. The committee recognizes that at a site as large and as obviously disturbed as the Coeur d’Alene River basin, there is no limit to the number or types of data-collection activities that could have been conducted. Similarly, any ERA of the scope and complexity of the Coeur d’Alene River basin ERA could be

1  

PRGs are proposed concentrations of materials in soil, sediment, and surface water below which adverse effects are expected to be absent or within defined limits. PRGs are provided to risk managers to assist in making decisions for remedial action (CH2M-Hill and URS Corp. 2001).



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