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Title: Evaluation of the 1980 capping operations at the experimental Mud Dump site, New York Bight Apex
Authors: New York University. Medical Center. Institute of Environmental Studies.
Valley Ecosystems.
Water Resources Support Center (U.S.)
United States. Army. Corps of Engineers. New York District.
Dredging Operations Technical Support Program (U.S.)
O'Connor, J. M. (Joseph M.)
O'Connor, Susan G.
Keywords: Contaminants
Dredged material disposal
Environmental effects
New York Bight
Ocean waste disposal
Dredging spoil
Publisher: Environmental Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Description: Technical Report
Abstract: Conflicting, multiple uses of the New York Bight impose various stresses on its physical and biological resources. Ocean disposal of waste poses a management problem which is regulated by no fewer than four pieces of Federal legislation and several State and Federal regulatory agencies. Dredged material disposal in the New York Bight is regulated by the U.S. Army Corps of Engineers. Current regulations dictate that contaminated dredged material be given special treatment. The special treatment discussed in this report is the capping of contaminated dredged material with clean material to isolate and minimize transport of toxicants from the sediment to marine biota. The objective of the project was to assess the potential for placing a cap at the experimental Mud Dump site, and to determine reductions in environmental impacts related to capping. Contaminated sediments from dredging projects in the Hudson Estuary, Newark Bay, and contiguous waters were capped first with fine sediments from the Bronx River and Westchester Creek, then with sand from the Ambrose Channel. The capping resulted in a layer of sand about 1 m thick lying atop the contaminated sediment. Physical, chemical, and biological studies were carried out to determine if the capping effort yielded an intact cap showing resistance to erosion, and if the effort reduced loss of organic and inorganic toxicants from the contaminated material to the water column. It was determined that a cap was successfully placed at the experimental dump site. The cap was still intact and in place after 16 months. Cap erosion was minor; predictions of cap life were in excess of 20 years under normal meteorological conditions. Major storm events, however, are capable of eroding the cap and exposing the contaminated material. During the 16 months of study, the contaminated material decreased in volume by about 4%. Part of the decrease was due to compaction and part was due to loss of solids during dumping and deposition. Chemical analyses showed that contaminant levels in the sand cap were lower than in the contaminated sediments. Bioaccumulation studies showed that less contaminant uptake occurred at the capping site than at uncapped dredged material sites and at sites in New York Harbor. The available data show that capping can be performed successfully in the New York Bight and that the thickness and stability of the cap can act to reduce losses of contaminants to the water column. Capping can serve as an alternative method for control of contaminants in dredged material. Capping can also be integrated with routine disposal operations to effectively cover and isolate contaminated dredged material at the designated dredged material disposal site.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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