20    DEVELOPING A REMEDIATION STRATEGY FOR
CONTAMINATED SEDIMENTS: SELECTING
REMOVAL, TREATMENT, DISPOSAL, AND RE-USE
ALTERNATIVES
Stanislaus J. Zagula, Chemical Engineer
Eberhard W. Beitinger, Senior Project Engineer
Woodward-Clyde Consultants
Chicago, Illinois 60603
INTRODUCTION
The need to develop cost-effective strategies to assess and remediate contaminated sediment has
come to the forefront of the regulated communities in both the public and private sector as the United
States Environmental Protection Agency (USEPA) changes the focus of its water pollution control
efforts from point source discharges to non-point sources. Contaminated sediment, a primary non-
point source of pollution, has been identified as one of the largest potential risks to water quality and
the aquatic environment.1 The concern over contaminated sediments stems from their tendency to
adsorb and accumulate toxic metals and organic chemicals which make their way into streams, lakes,
rivers, and harbors from a variety of sources. These contaminants may then be introduced into food
chains, ingested or absorbed through dermal contact, or released into the water column during mixing
and resuspension of the sediment. In the Great Lakes regions alone, contaminated sediments have
been identified as a problem in 42 of 43 Areas of Concern (AOCs). Nationally, nearly 25 percent of
National Priority List sites have been found to contain contaminated sediments and over 20 percent of
Superfund Records of Decision address potential sediment contamination.2 In addition, approximately 390 million cubic yards of sediment, some of which are potentially contaminated, are dredged
annually from waterways within the United States to maintain shipping channels and for flood
control.3
By enforcement of existing statutes, such as the Clean Water Act (CWA), the Toxic Substances
Control Act (TSCA), the Resource Conservation and Recovery Act (RCRA), and the Comprehensive
Environmental Response, Compensation, and Liabilities Act (CERCLA or Superfund), the USEPA is
addressing the cleanup of contaminated sediments through Consent Orders and Remedial Action
Plans. Proposed water quality programs, such as the Great Lakes Water Quality Guidelines (Great
Lakes Initiative) and international water quality agreements also address issues related to non-point
source pollution, including contaminated sediments. Developing an integrated approach to contaminated sediment removal, transport, treatment, disposal, and re-use, coupled with an understanding of
sediment characterization and assessment, will be fundamental to the successful implementation of
cost-effective remediation plans for contaminated sediments.
NATURE AND EXTENT OF CONTAMINATED SEDIMENT
Sediments can be defined as the fine, medium, and coarse grain mineral and organic particles that
are found at the bottom of lakes, rivers, bays, estuaries, and oceans. A large portion of these particles
are comprised of eroded soil which was transported and/or deposited by water or wind. Other
important components of sediment include organic matter, iron oxides, sulfides, carbonates, and the
interstitial water in equilibrium with the sediment. The organic matter consists of humus, plant and
animal detritus, and other organic material which settles to the bottom of a body of water, providing
substrate for a variety of benthic organisms (worms, amphipods, bivalves, etc.) at the base of the
aquatic food chain. In addition to the naturally deposited mineral and organic material and associated
benthic organisms, the sediment may contain larger vegetative, plant, and woody material, trash, and
debris.
Sediments are very heterogenous materials, however, they can be characterized by selected chemical
and physical properties, such as grain size distribution, water content, percent organic matter, and
48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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