. "3 Effectiveness of Environmental Dredging in Reducing Risk: Framework for Evaluation." Sediment Dredging at Superfund Megasites: Assessing the Effectiveness. Washington, DC: The National Academies Press, 2007.
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Sediment Dredging at Superfund Megasites: Assessing the Effectiveness
documented in the record of decision (ROD). However, this definition is appropriate for evaluating the effectiveness of the project in reducing risk only when cleanup goals are derived from sound, site-specific risk modeling.
An ideal evaluation of effectiveness at Superfund sites would be based on the site conceptual model, data from a baseline assessment, and a long-term monitoring program that permits sound statistical comparison of the spatial scale of contamination and the magnitude of risk before, during, and after dredging. At the outset of its work, the committee hoped to obtain that kind of information for a number of large contaminated sediment sites to inform its deliberations. However, we found that such careful and prolonged monitoring either has not been conducted, has not been completed at large-contaminated sediment sites, or simply was not available to the committee. (The committee noted that some sites where remediation had not yet occurred or been completed have electronic databases and long-term monitoring plans that would facilitate future attempts to evaluate remedy effectiveness, for example, Hudson River and New Bedford Harbor). In some cases, it is recognized that additional information, for example, raw data and consulting reports, may have been held by responsible parties, federal agencies, or their consultants. However, this information may not have been available in the public domain or to the committee, or the committee’s time and resource constraints precluded a thorough compilation, analysis, and interpretation (see further discussion in Chapter 4). In some cases a review of all site data was not necessary to determine whether cleanup goals had been met. This chapter details the committee’s process for evaluating the effectiveness of environmental dredging within the constraints imposed by the available data. The framework for this review is outlined in Box 3-1.
receptors are developed into final, chemical-specific, sediment cleanup levels by weighing a number of factors, including site-specific uncertainty factors and the criteria for remedy selection found in the NCP [National Contingency Plan]” (EPA 2005a, p. 2-16). The ROD for each site generally should include chemical-specific cleanup levels, indicating how these values are related to risk and how their attainment will be measured (EPA 2005a).