Contaminated Sediment Evaluation & Management
Dr. G. Fred Lee has been involved in research, advising, consulting, and publishing professional papers and reports on the water quality significance of contaminants in aquatic sediments for nearly five decades. Aquatic sediments tend to accumulate a variety of chemical constituents, such as PCBs, DDT, mercury, heavy metals, ammonia, and oxygen-demanding substances that pose various types of potential threats to water quality. Sediment-associated contaminants are of potential concern to organisms that live in and on the bedded sediment as well as to watercolumn organisms exposed to sediment resuspended with wind and tide action, boat/ship traffic, dredging, etc.
Dr. Lee has been involved in investigating and assessing the behavior and impacts of solids- and sediment-associated chemicals and pollutants, and aquatic sediments as a source of oxygen demand, since the early 1960s. He and his graduate students did some of the early research on the uptake, release, and water quality significance of contaminants, including PCBs, DDT, mercury, heavy metals, ammonia, and nutrients, in sediments, and on the leachability of radium 226 from mine waste (tailings). He has investigated, and his work has defined, key aspects of aqueous environmental chemistry that influence and control the uptake, release, and significance of sediment/solids-associated chemicals in aquatic systems. He incorporated his work into his teaching and education of graduate students in environmental engineering and science, and developed numerous professional papers and reports that discuss those findings. He and Dr. Jones-Lee have continued to be active in investigating the role of aquatic sediments as a source of PCBs that bioaccumulate to excessive concentrations in fish and other aquatic life.
Dr. Lee also became involved in evaluating the water quality significance of contaminants in dredged sediments in the late 1960s. In the 1970s he directed more than a million dollars in research on environmental quality impacts of dredging and dredged sediment disposal as part of the US Army Corps of Engineers Waterways Experiment Stationís $30-million, 5-year Dredged Material Research Program (DMRP) designed to evaluate the potential environmental quality impacts of the open water disposal of contaminated dredged sediment. That work, conducted by Dr. Lee and his associates, including Dr. Jones-Lee, was focused on developing criteria for the open-water disposal of contaminated dredged sediment, and included extensive, coordinated field and laboratory investigation of the release and impact of about 30 chemical contaminants (including heavy metals, chlorinated hydrocarbon pesticides, PCBs, aquatic plant nutrients, ammonia, and oxygen-demanding substances) from dredged sediment at about 100 urban/industrial waterway areas throughout the US. Their work revealed and documented the unreliability of total concentrations of contaminants in sediment as a basis for assessing the impact of sediment-associated contaminants on aquatic life. They field-evaluated the elutriate test and associated toxicity tests for making such assessments. The results of those studies were summarized and updated in Lee and Jones-Lee (2000) and Jones-Lee and Lee (2005).
Dr. Lee has also been active in evaluating potential environmental impacts of upland and on-land disposal of contaminated dredged sediments. While often been presumed to be a "safer" alternative for dredged sediment disposal, upland disposal of contaminated dredged sediments can lead to pollution of surface and/or groundwaters by contaminants in the dredged sediments. Public health and environmental quality impacts of on-land disposal are similar in many respects to those associated with disposal of solid wastes on land. In more recent years, Drs. Lee and Jones-Lee have undertaken a number of projects for clients to evaluate the public health and environmental quality impacts of sediment-associated contaminants in harbor sediments.
There continues to be considerable interest in, and attempts at, developing sediment quality criteria for evaluating and regulating contaminants in sediments. Key to making such assessments is understanding the sources, aqueous chemistry, water quality significance, evaluation, and comparative options for control of sediment-associated contaminants. However, those elements have often been inadequately, unreliably, or incorrectly incorporated into the evaluation and regulation protocols, rendering the results unreliable. While chemical-concentration-based approaches, such as equilibrium partitioning and co-occurrence, are being used for sediment quality assessment and regulation, such approaches cannot be relied upon, even for "screening," to provide a meaningful assessment of the water quality significance of chemicals in aquatic sediments. Dr. Leeís extensive background in these areas has enabled him to be active in the development and review of approaches being proposed for regulation of sediment-associated contaminants.
Many of Dr. Lee's professional papers and reports are available in the Contaminated Sediment Publications section of this website.
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