Project Specifics

Geosyntec is working with the U.S. Navy (Space and Naval Warfare Systems Command Systems Center Pacific, SSC-Pacific) to evaluate innovative remedial approaches for addressing contaminated sediment at the Pearl Harbor Naval Complex Superfund Site at Joint Base Pearl Harbor–Hickam in Pearl Harbor, Hawaii. The site is a large, complex estuary (approximately 5,000 acres) with numerous areas identified for active management of contaminated sediments.

Geosyntec Scope of Services

Geosyntec is working with the U.S. Navy on evaluating the use of uncontaminated dredge spoils, which were removed to facilitate navigation in the main channels of Pearl Harbor, as a potential source of material to remediate contaminated sediments.  The placement of a thin layer of the uncontaminated dredged material is designed to aid in the natural recovery of the contaminated sediment, reducing the availability and mobility of contaminants including metals and polychlorinated biphenyls (PCBs).  Use of the dredged material is an efficient and “green”; option, as it avoids having to dispose the sediment in another location.

Geosyntec worked closely with the U.S. Navy to design and implement a pilot study to evaluate the use of dredged materials for application at a contaminated site within Pearl Harbor.  In addition to evaluation of the materials, remedial application rates, and experimental design, Geosyntec’s SiREM laboratory designed customized passive samplers (http://www.siremlab.com/sediment-pore-water-sampler/) to evaluate the changes in metal and PCB availability that were projected to occur as a result of the placement of the uncontaminated dredge spoil.  Geosyntec conducted the field work at Pearl Harbor to place and process the samplers, and evaluated the resulting data.

Notable Accomplishments

Geosyntecs review of the Initial data obtained using the customized passive samplers indicates that  placement of the dredged material did indeed reduce contaminant availability and mobility by approximately 80 to 90%. These results show that the use of uncontaminated dredge spoil may be a successful and extremely cost-effective remedial option for remediating contaminated sediment. Additional field work and data evaluation is currently underway. Geosyntec’s SiREM laboratory is the industry leader in passive sampling and has applied over 1,000 passive samplers  in soil, water, and sediment for a variety of different applications and clients under the oversight of Canadian and U.S. Federal and State regulatory agencies.

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