Transferring Laboratory Success into the Field.
Initial Research, and the Hunter's Point and Grasse River Pilot Studies
The early research on using sorbents such as activated carbon to reduce the bioavailability of contaminants in sediment followed the use of these materials for removing chemicals from water. Laboratory experiments shown significant reduction in the uptake and toxicity of hydrophobic organic chemicals to benthic organisms.
Early pilot studies that transferred the laboratory successes of activated carbon in reducing the bioavailability of hydrophobic chemicals in sediment to the field were conducted at Hunter's Point and Grasse River. Activated carbon was mechanically mixed into intertidal sediments at Hunter's Point, while the Grasse River project involved the injection, mechanical mixing, and layering of activated carbon slurry onto contaminated river sediments.
Reductions in the bioavailability of PCBs and PAHs were found to be in the range of 60 to 90%. At Grasse River, activated carbon doses of greater than 4% by sediment dry weight resulted in 90 to 99% reductions in PCB bioavailability. Additional studies on the effects of activated carbon to the benthic community shown no adverse effects.
These early field pilot studies not only demonstrated the efficacy of activated carbon in remediating sediments in-situ, but also highlighted the primary limitation: effective delivery of activated carbon to sediment. This requirement drove the creation of SediMite.
Field scale reduction of PCB bioavailability with activated carbon amendment to river sediments. Barbara Beckingham and Upal Ghosh. Environ. Sci. Technol., 45, 10567–10574, 2011.
In-situ sorbent amendments: A new direction in contaminated sediment management. Upal Ghosh, Richard G. Luthy, Gerard Cornelissen, David Werner, Charles A. Menzie. Environ. Sci. Technol. Feature Article, 45, 1163–1168. 2011.
Field application of activated carbon amendment for in-situ stabilization of polychlorinated biphenyls in marine sediment. Cho, Y., Ghosh, U., Kennedy, A. J., Grossman*, A., Ray, G.; Tomaszewski, J. E., Smithenry, D., Bridges, T. S., Luthy, R. G. Environ. Sci. Technol. 43, 3815-3823, 2009.
PCB Bioavailability Control in Lumbriculus variegatus Through Different Modes of Activated Carbon Addition to Sediments. X. Sun* and U. Ghosh. Environ. Sci. Technol. 41, 4774-4780, 2007.
In Situ Stabilization of Persistent Hydrophobic Organic Contaminants in Sediments using coal- and wood-derived carbon sorbents. R.G. Luthy and U. Ghosh, 2006 (US patent # 7,101,115)