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Sampling and Analysis of Gas Collection Systems Flux Chambers at Eagle Harbor, Bainbridge Island, Washington
A common remediation technology for contaminated sediments is capping. Capping is performed by covering the contaminated sediments with sand, gravel, or other fine-grained dredged material. Because most forms of capping do not employ an impermeable barrier, a concern is whether the capped contaminant will migrate through the cap. As sediment undergoes compaction and anaerobic degradation occurs, anaerobic gases are released. The types of released products, amounts, and effects have not yet been fully evaluated. Gases generated during the anaerobic degradation of capped contaminated sediments with high organic content are also an available co-solvent which could facilitate the transport of other contaminants through the capping material into the water column. To evaluate the potential for gases generated by sediments containing high levels of organic material to migrate through permeable caps into the surrounding water column, EPA installed, as part of a sediment gas collection system, sediment gas flux chambers in the contaminated sediment layer in Eagle Harbor, Bainbridge Island, Washington. In FY 2003 Eagle Harbor was sampled twice (every six months) and is sampled annually; sampling this year is scheduled in April.
Contact: Terrence Lyons, USEPA, (EIMS#56581)