“Standardization of Polymeric Sampling for Measuring Freely Dissolved Organic Contaminant Concentrations in Sediment Porewater” by Dr. Mandy Michalsen (ESTCP Project ER-201735)

Polymeric samplers consist of hydrophobic polymers (e.g., polyethylene orpolydimethylsiloxane) that can be directly inserted into sediment in the laboratory (ex situ) or in the field (in situ) to yield depth-discreet measures of freely-dissolved organic contaminant concentrations (Cfree) in sediment porewater. Cfree can improve predictions of chemical toxicity and bioaccumulation in benthic organisms compared to bulk sediment-based porewater concentration estimates. Polymeric samplers are widely used for environmental monitoring, but their acceptance is limited by the lack of standard methods and commercial availability. As part of this SERDP effort, multiple university and commercial analytical laboratories collaborated on a phased project to standardize polymeric sampler methods, then validate the standardized method through an interlaboratory demonstration. This webinar (1) introduced the standardized polymeric sampler methods for quantifying polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) Cfree in sediment porewater, (2) presented results of the interlaboratory method demonstration performed using replicates of a single homogenized sediment sample, (3) compared polymeric sampler-determined Cfree results to porewater concentrations measured via two alternative methods (airbridge and manual porewater extraction with flocculation to remove sediment colloids prior to analysis), and (4) summarized lessons learned.

“Long-Term Monitoring of Activated Carbon Amendment to Reduce PCB Bioavailability in Sediments at an Active Shipyard” by Mr. Gunther Rosen (ESTCP Project ER18-5079)

Activated carbon (AC) amendments have been demonstrated under multiple SERDP and ESTCP projects as effective and minimally disruptive means of sequestering sediment-associated hydrophobic organic contaminants. In 2012, an AC-amendment (AquaGate+PAC™) was placed at a half-acre plot adjacent to, and underneath, a working pier (Pier 7) at the Puget Sound Naval Shipyard & Intermediated Maintenance Facility to reduce PCB availability in surface sediment. Multiple lines of evidence, including the use of unique in situ assessment tools, were successful in verifying remedy presence, performance and benthic community health over a three-year period, showing a consistent 80% to 90% or higher reduction in available PCBs relative to baseline conditions. Long-term performance of AC amendments, particularly in active, deep water Navy harbors, however, is not yet well understood. This research effort involved comprehensive monitoring for seven years following implementation of the AC remedy at Pier 7 to assess the long-term effectiveness and stability of the amendment, and long-term potential for adverse impacts to the benthic community. This presentation compared long-term monitoring results with baseline and short-term post placement results using similar assessment tools, and offered considerations towards additional methods to support verification of AC presence over time.

Dr. Mandy Michalsen is a research engineer with the U.S. Army Engineer Research Development Center (ERDC) in Seattle, Washington. Dr. Michalsen’s current research focuses on novel applications of groundwater remediation technologies to accelerate cleanup of explosives- and chlorinated solvent-contaminated aquifers, and polymeric samplers for measuring freely-dissolved contaminants in sediment porewater. Prior to joining ERDC in November 2014, Dr. Michalsen served as Chief of Soils at the U.S. Army Corps of Engineers Seattle District. She has served as principal investigator and lead engineer on field-scale technology demonstrations and full-scale groundwater remedy optimization projects, resulting in multiple peer-reviewed research papers. She holds a bachelor’s degree in civil engineering from the University of Iowa, and master’s and doctoral degrees in civil engineering from Oregon State University. 

Mr. Gunther Rosen is an aquatic biologist with the Naval Information Warfare Center (NIWC) Pacific in San Diego, California. His primary research interests are in aquatic and sediment ecotoxicology. He has conducted basic and applied research for the Navy primarily in support of improved management of contaminated discharges and sediments. Frequently serving as principal investigator, his research focuses on understanding the bioavailability and toxicity of DoD-relevant contaminants on ecological receptors, and the development, demonstration and validation of technologies to improve environmental quality assessment. He has over 50 publications in peer-reviewed journals and oversees projects across a wide range of related topics, including metal and organic contaminant bioavailability, stormwater impacts, in situ characterization and remediation tools, and underwater munitions, many of which were supported by the SERDP and ESTCP. Mr. Rosen holds a bachelor’s degree in aquatic biology from the University of California, Santa Barbara, and a master’s degree in fisheries science from Oregon State University.