Contaminated Sediments Program
- Great Lakes Monitoring
- Monitoring and Assessment Water Quality
- Global Earth Observation System of Systems (GEOSS)
A Report on the Sediment Assessment and Remediation Program in the Great Lakes Basin - April 1997
Table of Contents
Moving Mud - Remediating Great Lakes Contaminated Sediments
Contaminated sediments first began to be noticed as a serious environmental problem in the early 1970's. Increases in the concentrations of the pesticide DDT and a group of chemicals known as polychlorinated biphenyls (PCBs) were noticed in the tissues of Great Lakes fish. Although these chemicals had been banned for several years, concentrations in the tissues of fish and other animals were actually beginning to increase. While some of the increase was found to be from airborne contaminants, research also directed attention to the role of contaminated sediments.
Contaminated sediments have been created by decades of industrial and municipal discharges, combined sewer overflows, and urban and agricultural non-point source runoff. Buried contaminants posing serious human and ecological health concerns can be resuspended by storms, ship propellers, and bottom-dwelling organisms. Many of these small bottom-dwellers ingest toxins as they feed in the mud. As larger animals eat these smaller animals, the toxins move up the food chain, their concentrations getting higher, often thousands of times higher. Fish at the top of the Great Lakes food chain such as lake trout and salmon can be considered unsafe to eat in some areas because of the heavy concentrations of toxic substances in their tissues. Fish-eating birds, including the bald eagle, may suffer low reproductive rates or produce offspring with birth defects.
Scientific research has confirmed the significance of bottom sediments as an ongoing source of contaminants to the Great Lakes. A study of PCBs in Green Bay found that greater than 90 percent of the ongoing PCB contamination in Green Bay sport fish came from contaminated bottom sediments, both within the bay and in the Fox River. Monitoring of Lake Superior during the past decade suggests a similar conclusion - that the release of PCBs from the bottom sediments is the dominating source of food web contamination (USEPA, 1994).
This link between contaminated sediments and water quality provides the basis for the GLNPO sediment program. The Federal Water Pollution Control Act Amendments of 1972 declare as a national goal that all waters of the United States be made clean enough for fishing and swimming. The Clean Water Act of 1977 seeks to secure "water quality which provides for the protection and propagation of fish, shellfish, and wildlife, and provides for recreation in and out of the water." The 1978 Great Lakes Water Quality Agreement has specific relevance to GLNPO's mission. The purpose of the Agreement is to "restore and maintain the chemical, physical, and biological integrity of the waters of the Great Lakes basin ecosystem." This charges the USEPA, and GLNPO in particular, with the responsibility to ensure protection and restoration of Great Lakes habitats.
Although contaminated sediments were recognized as a serious environmental threat at the time that these laws and documents were being drafted, the information necessary to successfully address the problem did not exist. In an attempt to focus efforts on the issue of contaminated sediments, Congress, in the 1987 amendments to the Clean Water Act, authorized GLNPO to coordinate and conduct a five-year study and demonstration project relating to the appropriate treatment of toxic pollutants in bottom sediments. To fulfill the requirements of this Congressional mandate, GLNPO initiated the Assessment and Remediation of Contaminated Sediments (ARCS) Program. ARCS was an integrated program for the development and testing of remedial action alternatives for contaminated sediments.
The ARCS Program had the following objectives:
- Assess the nature and extent of bottom sediment contamination at selected Great Lakes Area Of Concerns (AOCs);
- Demonstrate and evaluate the effectiveness of selected remedial options; and,
- Provide guidance on contaminated sediment problems and remedial alternatives in the AOCs and other locations in the Great Lakes.
The efforts of many researchers were directed toward developing and demonstrating sediment assessment and cleanup approaches that were scientifically sound, and technologically and economically feasible.
Major findings and recommendations of the ARCS Program included the following:
- Use of an integrated sediment assessment approach, incorporating chemical analyses, toxicity testing, and benthic community surveys, is essential to define the magnitude and extent of sediment contamination at a site;
- Risk assessment and modeling activities are valuable techniques for evaluating the impacts of contaminated sediments;
- Numerous treatment technologies are effective in removing or destroying sediment contaminants; and,
- Broad public outreach and education are critical in any sediment assessment and remediation study.
The information gained and tools developed during the ARCS Program for assessing sediment contamination and for making remediation decisions are included in a series of 45 documents that are available from GLNPO. A complete listing and full text or abridged versions of these documents can be found on GLNPO's World Wide Web homepage. To obtain a hard copy of one or more of the ARCS documents, please contact:
Mr. Lawrence Brail ADS [Contractor]
U.S. Environmental Protection Agency
Great Lakes National Program Office
77 W. Jackson Boulevard [G-17J]
Chicago, IL 60604
Tel: (312) 886-7474
Fax: (312) 353-2018
The information contained in these documents is now being applied to projects addressing contaminated sediment problems in Areas of Concern across the Great Lakes.
I would like to thank Callie Bolattino and Marc Tuchman
of the GLNPO Sediment Assessment and Remediation team for their valuable
comments, suggestions, and encouragement which were offered throughout
the project. I would like to recognize the Grantees for their creativity
and hard work which provided the basis for this report, and for their interest
and critical reviews during the project. Thanks also go to GLNPO staff
David Cowgill, Chief of the Technical Assistance and Analysis Branch,
and Darlene Funches, Computer Specialist/Desktop Publishing, for
their suggestions and help in assembling the final product.