Implementation of In Situ Activated Carbon
Remedies at Contaminated Sediment Sites



The SEA Ring is a device design to allow for in situ biological toxicity testing and/or bioaccumulation studies. The SEA Ring was demonstrated as an ESTCP project, and the demonstration report can be found at the project web page ESTCP Project ER-201130.

PSNS Pier 7 AC Demonstration Project
The SEA Ring system was employed as part of the AC demonstration project at the PSNS Pier 7 at the Puget Sound Naval Shipyard in Bremerton, WA. The principal contaminants of concern for that project were PCBs and mercury.

SEA Ring was used to assess biological effectiveness performance objectives from placement of particulate activated carbon. Remedy effectiveness was assess in situ with the SEA Ring exposure chambers placed directly on/into the treated sediments. The chambers were inoculated with Macoma nasuta (clam), and Nephtys caecoides (polychaete) in 14-day exposures to measure PCB and mercury bioaccumulation.

Preparation of the SEA Ring system prior to deployment onto the sea floor at PSNS Pier 7. Photos show the method of placing the polychaetes and clams into the exposure chambers, which is done underwater by divers after the bottom of the chambers have been pressed into the remediated sediment. Critical to the operation of the SEA Ring is a pump which circulates water through the chambers to maintain oxygen content.

At the PSNS site, US Navy Divers were used to deploy and retrieve the SEA rings at the AC remediated area. The SEA rings were prepared for deployment dockside; the divers took the units down, pushed the chambers on the unit into the sea floor, and then inoculated them with the test organisms. Deployment was for 14 days.

Upon retrieval, the SEA Ring chambers (tubes) were processed to recover the inoculated clams and polychaetes to measure PCB and Hg bioaccumulation, bulk sediment for physical and chemical analyses, and benthic organisms to assess whether AC had any effects on the resident infauna.

Performance Assessment
Puget Sound Naval Shipyard

Additional Resources

  • Demonstration and Commercialization of the Sediment Ecosystem Assessment Protocol (SEAP) ESTCP Project ER-201130
  • Demonstration of an In Situ Toxicity and Bioaccumulation Testing Technology for More Realistic Exposure Assessment Webinar
  • Demonstration of in situ Treatment with Reactive Amendments for Contaminated Sediments in Active DoD Harbors. ESTCP Project 201131
  • Demonstration and Validation of Enhanced Monitored Natural Recovery at Department of Defense Sediment Sites. ESTCP Project ER-201368 SEA Ring was used as a monitoring tool for EMNR at the Quantico remediation site.

Contacts for Information on SEA Ring

Gunther Rosen
Dr. Bart Chadwick