"Demonstration of an In Situ Toxicity and Bioaccumulation Testing Technology for More Realistic Exposure Assessment" by Mr. Gunther Rosen
The purpose of this ESTCP project was to advance, demonstrate, commercialize, and promote regulatory acceptance of a field-deployed bioassay system known as the Sediment Ecotoxicity Assessment Ring (SEA Ring). SEA Ring was previously developed under SERDP. It integrates in situ biological uptake and effects measures with passive sampling devices and physicochemical tools to assess sediment and water quality. The device is particularly relevant for situations where traditional laboratory-based bioassays are insufficient to accurately characterize exposure. Examples include, but are not limited to (1) in situ remedy effectiveness and (2) time-varying stressors (e.g., storm water discharges, underwater unexploded ordnance, tidally-influenced groundwater seepage). The SEA Ring system results in a more realistic exposure assessment, resulting in improved decision-making with respect to the need for remediation. This presentation summarized the evolution of the technology, and provide an overview of results from three site demonstrations: Puget Sound Naval Shipyard (reactive amendment effectiveness), Marine Corps Base Quantico (thin-layer cap effectiveness), and Naval Base San Diego (stormwater impacts on a receiving environment).
“Pilot-Scale Performance of In Situ Treatment with Reactive Carbon Amendments for Contaminated Sediments at an Active DoD Harbor Site by Dr. Bart Chadwick
In situ treatment using activated carbon is an emerging and potentially cost-effective remedial approach for sediments in active harbor areas with infrastructure, vessel traffic, varying water depths and other logistical requirements. In this project, a thin layer of activated carbon was placed on top of PCB-impacted sediments at Pier 7, Puget Sound Naval Shipyard and Intermediate Maintenance Facility, Bremerton, Washington. Natural processes were relied upon to mix the carbon into the bioactive sediment layer following placement over the 0.5-acre area. Following material placement using conveyor belt-type equipment in both a deep water area alongside and under Pier 7, monitoring was performed over a three-year period to demonstrate and validate material placement, stability, amendment performance, persistence of reactive amendments, and changes in the benthic community. Post-application diver and Sediment Profile Imagery (SPI) surveys indicated that the target application thickness was attained in at least 90% of the area, even on the sides of steep sump slopes. Total PCB concentrations in exposed organisms in situ decreased 82 to 97% compared to baseline and these decreases persisted over time. PCB concentrations in surface sediment porewater samples decreased by 75 to 86%. The remedy was therefore effective in reducing PCB availability in surface sediments. Benthic taxa were largely unaffected by the amendment placement and the diversity of the benthic community increased. Remaining questions include longer-term persistence of the remedy, strategies for integrating measures of remedy effectiveness into regulatory decision-making, requirements and optimization for long-term monitoring, and cost-effectiveness relative to other remedies.
Mr. Gunther Rosen is an Aquatic Biologist with the Space and Naval Warfare Systems Center Pacific (SSC Pacific) in San Diego, California. His primary research interests are in aquatic and sediment ecotoxicology. For the past 18 years, Gunther has conducted basic and applied research for the Navy primarily in support of improved management of contaminated discharges and sediments. His research focuses on understanding the bioavailability and toxicity of DoD-relevant contaminants on marine biota, and the development, or demonstration and validation, of technologies to improve environmental quality assessment. He regularly publishes in peer-reviewed journals, and oversees projects across a wide range of related topics including metal bioavailability, stormwater impacts, in situ assessment and remediation, and underwater munitions, many of which have been supported by SERDP and ESTCP. Mr. Rosen received a Bachelor’s degree in Aquatic Biology from the University of California, Santa Barbara in 1993 and a Master’s degree in Aquaculture from Oregon State University in 1998.
Dr. Bart Chadwick currently directs research and business development for the U.S Navy’s Energy and Environmental Sciences Group, SPAWAR Systems Center Pacific. He has extensive experience in oceanography, engineering, technology development, measurement and modeling of the marine environment. His research spans areas of environmental assessment, climate change vulnerability, and energy harvesting. Dr. Chadwick manages a portfolio of emerging energy and environmental projects, and has served as a principal investigator on a number of high visibility research projects support by SERDP and ESTCP. The focus of these projects includes the fate and transport of heavy metals in harbors, processes that control the fate and transport of contaminants in sediments, groundwater surface water interaction assessment tools, climate change and sea level rise vulnerability, and sediment microbial fuel cells. Dr. Chadwick earned his B.S. in Engineering from the University of California, Berkeley, and his Ph.D. in Oceanography from Scripps Institution of Oceanography, University of California, San Diego.