Contaminated Sediments in Ports and Waterways Cleanup Strategies and Technologies (1997) / Chapter Skim
Currently Skimming:
1 The Challenge
1 The Challenge
Pages 15-29
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From page 15... ...
Chemical contaminants associated with sediments can be considered toxic when they adversely affect living organisms. Submerged contaminated sediments may be in intimate contact with aquatic biota that may be affected adversely by, or serve as carriers of, contamination.
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From page 16... ...
At the legal level, ports that may have no causal role in the contamination of sediments but must still dredge channels are faced with a number of hurdles, including identifying and paying for space for the placement of dredged material and many chemical, regulatory, political, and technological challenges.2 Proper management of contaminated sediments is becoming more complicated because environmental concerns increasingly hinder the removal of sediments from economically critical shipping lanes and because growing numbers of contaminated sites are being identified for remediation. DRIVING FORCES FOR REMEDIATION Contaminated sediment becomes an issue when an environmental or human health risk is identified or when navigational needs require that contaminated sediment be dredged from shipping channels.
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From page 17... ...
Note: USACE, U.S. Army Corps of Engineers; CWA, Clean Water Act; CZMA, Coastal Zone Management Act; DOI, Department of the Interior; EPA, Environmental Protection Agency; ESA, Endangered Species Act; MPRSA, Marine Protection, Research and Sanctuaries Act; NOAA, National Oceanic and Atmospheric Administration; RCRA/CERCLA, Resource Conservation and Recovery Act/Comprehensive 17 Environmental Response, Cleanup, and Liability Act; RHA, Rivers and Harbors Act; state, any state government.
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From page 18... ...
assists in the design and implementation of remedial actions under Superfund and exercises primary responsibilities for permitting dredged material under the CWA, MPRSA, and Rivers and Harbors Act. The federal navigation dredging program is the responsibility of the EPA and USACE; the EPA addresses issues pertaining to disposal, and the USACE handles the dredging.
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From page 19... ...
In situ remediation strategies, such as leaving the contaminated sediment in place (i.e., allowing natural recovery to occur) , may not be feasible in navigation channels.
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From page 20... ...
For major projects, environmental regulators require that all alternatives be explored before a decision to dredge is made, to ensure that a less costly or more environmentally acceptable alternative has not been overlooked. Although the economic impact of not dredging sediment is difficult to quantify, there is no doubt that well maintained channels, ports, and harbors are essential if the United States is to continue to attract and retain commercial shipping (Interagency Working Group on the Dredging Process, 1994)
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From page 21... ...
Federal cost-sharing policies make a distinction between new-work dredging, for which the local sponsor must share the cost, and maintenance dredging, which is financed fully by the federal government through the Harbor Maintenance Trust Fund.5 New-construction dredging is motivated primarily by economics -- that is, regional development pressures as well as the competitive position of a local port in relation to neighboring ports. Port upgrades also benefit the nation as a whole by supporting trade, an important element of the U.S.
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From page 22... ...
RISK MANAGEMENT PROCESS Contaminated marine sediments can pose risks to public health and the environment, and sound decisions about health and ecological risks must be based on formal assessments of those risks. The most elemental form of risk assessment is intended to determine whether the concentrations likely to be encountered by organisms are higher or lower than the level identified as causing an unacceptable effect.
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From page 23... ...
Because of the physiochemical state of the hydrophobic organics, they tend either to sorb to natural organic matter and fine clays or to be partitioned into a separate liquid phase, such as oil or coal tar. As a result, most highly contaminated sediments, regardless of the source of the contamination, tend to be fine-grained materials deposited in low-energy areas, which serve as sinks.
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Regulatory and Legal Challenges The regulations affecting contaminated sediments management are complicated. They were developed to implement a range of unrelated federal and state statutes dealing with issues, such as water quality and hazardous waste cleanup.
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If sediments proposed for ocean disposal are deemed to contain mercury or cadmium compounds, organohalogens, or petroleum hydrocarbons (as other than "trace contaminants") based on prescribed bioassay and bioaccumulation testing procedures, then ocean dumping may be prohibited, although discharge into inland waters may be acceptable as long as the sediments satisfy applicable regulations and guidelines under Section 404 of the CWA.
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From page 26... ...
The diverse areas of expertise and interests of multiple agencies can be accommodated as long as they are applied in a constructive way to accomplish a logical, risk-based objective. Political Challenges The risk posed by contaminated marine sediment is neither easily measured nor highly visible -- characteristics that may foster disagreements among stakeholders about how to manage the problem.
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From page 27... ...
They may want remedial action but oppose the deposition of dredged sediment on nearby land or in the ocean. Management Challenges Many strategies for managing contaminated sediments are available, some of them very sophisticated.
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From page 28... ...
The beneficial reuse of clean or contaminated dredged material can improve prospects for success. Although there is clearly room to increase the effectiveness and reduce the costs of contaminated sediment management, there is also a built-in bias against innovation.
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From page 29... ...
1989. Grain size partitioning of metals in contaminated coarse grained river flood plain sediments, Clark Fork River, Montana, USA.
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