Sediment Dredging at Superfund Megasites Assessing the Effectiveness (2007) / Chapter Skim
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3 Effectiveness of Environmental Dredging in Reducing Risk: Framework for Evaluation
3 Effectiveness of Environmental Dredging in Reducing Risk: Framework for Evaluation
Pages 70-89
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From page 70... ...
. In conducting its evaluation, the committee defined dredging effectiveness as the achievement of cleanup goals defined for each site, which take the form of remedial-action objectives, remediation goals, and cleanup levels.1 For CERCLA remedial actions, these goals are typically 1Remedial-action objectives "are intended to provide a general description of what remediation is expected to accomplish" (EPA 2005a, p.
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From page 71... ...
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]
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From page 72... ...
From those dredging sites, EPA provided the committee with a list of sites on which there were pre-remediation and post-remediation monitoring data. To identify other dredging projects for possible evaluation, the committee reviewed information from additional government, industry, and private consulting sources that summarize remedial activities at contaminated sediment sites (see Box 3-2)
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From page 73... ...
Many of the same case studies were also reviewed by EPA (Hahnenberg 1999) , and EPA presented the results of its analysis to the National Research Council's Committee on Remediation of PCB-Contaminated Sediments (NRC 2001)
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From page 74... ...
The U.S. Army Corps of Engineers Center for Contaminated Sediments also provided information on a series of environmental-dredging projects (USACE 2006)
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From page 75... ...
Therefore, another criterion used by the committee to select dredging projects was whether they had pre-dredging and post-dredging monitoring data. Environmental-dredging projects occur in a wide variety of aquatic environments, such as rivers, estuaries, bays, lakes, ponds, canals, and wetlands; and the effectiveness of dredging can be influenced by many BOX 3-3 Criteria Used to Select Environmental-Dredging Projects for Evaluation 1.
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From page 76... ...
. The committee also chose three demonstration projects (two in the Lower Fox River, WI, and one in the Grasse River, NY)
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From page 77... ...
TABLE 3-1 Summary of 26 Environmental-Dredging Projects Selected for Evaluationa Primary Chemicals of Scale of Dates of Volume of Dredged Project Water- Body Type Remedy Type Effort Dredging Sediment (cy) Concern Bayou Bonfouca, PAHs Bayou Dredging followed by Full-scale 1994-1995 170,000 LA backfilling Lavaca Bay, TX Hg Estuary Dredging Pilot 1998 80,000 Black River, OH PAHs River Dredging Full-scale 1989-1990 45,000-60,000 Outboard PCBs Harbor Dredging Full-scale 1991-1992 38,000 Marine Corp., Waukegan Harbor, IL Commencement PCBs, As, Estuary Dredging Full-scale 2003-2006b 419,000c Bay–Head of PAHs Hylebos, Tacoma, WA Commencement As, Cu Estuary Dredging Full-scale 1993-1994 428,000d Bay–Sitcum, Tacoma, WA Duwamish PCBs Tidally influenced Dredging followed by Full-scale 2003-2004 66,000 Diagonal, river capping Seattle, WA (Continued on next page)
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From page 78... ...
, WI Lower Fox River PCBs River Dredging Pilot 1998-1999 8,200 (Deposit N)
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From page 79... ...
Lawrence River, NY Grasse River, PCBs River Dredging Pilot 1995 3,000 NY (non-timecritical removal action) Grasse River, PCBs River Dredging and backfilling Pilot 2005 30,000 NY remedial options pilot study (ROPS)
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From page 80... ...
total (backfilling in one area) Lawrence River, dibenzofuran NY Marathon Cd River Dredging Full-scale 1993-1995 71,000 Battery, Hudson River, Cold Spring, NY New Bedford PCBs Estuary Dredging Full-scale 1994-1995 14,000 Harbor, MA (hot (hot spot spot)
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From page 81... ...
. fFrom EPA summary (EPA 2006 [Harbor Island Lockheed Shipyard Sediment Operable Unit, May 11, 2006]
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From page 82... ...
. Of the 26 dredging projects, five have been identified by EPA as contaminated sediment megasites, that is, sites where the dredging portion of the remedy will cost at least $50 million (see "Sediment Contamination at Superfund Sites" in Chapter 2)
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From page 83... ...
▪ Methods for improving the monitoring of dredging effectiveness. The committee did not attempt to substitute its own judgment about what remedial action objectives and cleanup levels should be, including the site-specific risk modeling on which they were based, but simply tried to determine whether the stated goals were achieved and why or why not.
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From page 84... ...
Methods Used to Evaluate Dredging Projects Each project review began with the identification of the remedial action objectives and cleanup levels for the project. That was followed by review of project data to judge whether the remedial action objectives and cleanup levels had been met.
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From page 85... ...
For example, have remedial action objectives been achieved? Do data demonstrate or at least suggest a reduction in fish tissue concentrations, a decrease in benthic toxicity, or an increase in species diversity or other community indexes after 5 years?
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From page 86... ...
Site Profiles of Sediment Dredging Projects. Draft for State and Federal Review.
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From page 87... ...
2000. Realizing Remediation II: A Summary of Contaminated Sediment Remediation Activities at Great Lakes Areas of Concern.
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From page 88... ...
2006. SMWG Review and Analysis of Selected Sediment Dredging Projects.
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From page 89... ...
1999. Ecological Benefits of Contami nated Sediment Remediation in the Great Lakes Basin.
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