This seminar will feature SRP grantees Dr. Peggy O'Day (University of California - Merced) and Dr. Tom Sheahan (Northeastern University), and will be moderated by Karl Gustavson (US EPA). Dr. O'Day will present an overview of different types of reactive amendments, mechanisms and chemistry associated with contaminant sequestration, examples of recent applications, and opportunities for the use of new materials and delivery methods. Dr. Sheahan will describe a bench-scale experimental study to examine the efficacy of the reactive geocomposite mats or overlays (RCM) to isolate and partially remediate PCB- and PAH-contaminated sediment, and to provide sufficient sequestering functionality to minimize biouptake by organisms in clean sediment overlying the RCM. He will present the results from a series of tests on spiked natural sediment using a new device developed for this research, the Integrated Contaminated Sediment Testing Apparatus Column (ICSTAC).
Reactive Amendments for Remediation of Metal and Metalloid Contaminants in Soils and Sediments, Dr. Peggy O'day, School of Natural Sciences, University of California, Merced
Reactive amendments are chemical or mineral-based materials designed to react in situ with soils, sediments, and porewater through direct contact or emplacement in caps or barriers. Metal and metalloid elements such as lead, cadmium, arsenic, mercury, chromium, and selenium are especially problematic contaminants because they are considered hazardous at low bulk solid concentrations (i.e., low mg kg-1), they are often dispersed widely in soils and sediments at contaminated sites, and their speciation, mobility, and bioavailability are influenced by environmental factors such pH and oxidation-reduction potential (Eh or pe). This seminar will present an overview of different types of reactive amendments, mechanisms and chemistry associated with contaminant sequestration, examples of recent applications, and opportunities for the use of new materials and delivery methods.
Reactive Geocomposite Sediment Mats: Adaptable Remediation Tools, Department of Civil and Environmental Engineering at Northeastern University
Reactive geomposite mats or overlays (RCM) represent a new class of sediment remediation tools, consisting of a reactive layer containing one or more neutralizing or otherwise reactive materials (e.g., organoclay, apatite, activated carbon) that is confined between two filtering geotextile layers. The presentation describes a bench-scale experimental study to examine the efficacy of the RCM to isolate and partially remediate PCB- and PAH-contaminated sediment, and to provide sufficient sequestering functionality to minimize biouptake by organisms in clean sediment overlying the RCM. Results are presented from a series of tests on spiked natural sediment using a new device developed for this research, the Integrated Contaminated Sediment Testing Apparatus Column (ICSTAC).
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