Jason Conder, Ph.D., (California), Jennifer Arblaster (Vermont), and Alice Wang, Ph.D., (Massachusetts) will present at the Society of Environmental Toxicology and Chemistry (SETAC) North America 41st Annual Meeting at 8:00-12:00 PM CST on November 15, 2020.

Jason and Jennifer will lead a short course entitled “Assessing the Ecological Risks of Per- and Polyfluoroalkyl Substances (PFAS) at Aqueous Film Forming Foam Sites” with co-instructor Chris Higgins, Colorado School of Mines.

Jason Conder is a Principal Scientist based in California with more than 15 years of experience focused on risk assessment and contaminated sediments in contaminated site assessment and management, environmental toxicology, and ecological and human health risk assessment.

Jennifer Arblaster is a Project Scientist based in Vermont with experience in ecological and human health risk assessment, sediment site characterization, bioaccumulation modeling and evaluation of environmental quality criteria.

Alice Wang is a Senior Staff Professional based in Massachusetts with more than a decade of experience in civil and environmental engineering and data reporting and analysis. Her research experience includes sustainable engineering, passive sampling, and remediation of polychlorinated biphenyl-contaminated sediment.

Considering the growing number of challenges facing our environment, now more than ever, the need is evident for environmental professionals to focus and work together at a global scale to address these issues. Under such a paradigm, discrete technical advances would be leveraged to create harmonized approaches towards mutual solutions. The SETAC meeting offers opportunities to focus on transdisciplinary advances within a holistic system approach to meet these challenges head on.

SETAC is a not-for-profit, worldwide professional organization composed of about 5,300 individuals and institution in more than 90 countries dedicated to the study, analysis and solution of environmental problems, the management and regulation of natural resources, research and development and environmental education. The society has more than 20,000 followers worldwide.

Geosyntec Participation

Title: Assessing the Ecological Risks of Per- and Polyfluoroalkyl Substances (PFAS) at Aqueous Film Forming Foam Sites

Instructors: Jason Conder, Jennifer Arblaster, Geosyntec Consultants; Chris Higgins, Colorado School of Mines
Time: 8:00 AM CST on November 15, 2020

This course will provide an overview of ecological risk assessment for PFAS, including an overview of the fate, exposure, and toxicity of PFAS in ecosystems. The presentation will focus on our recently released SERDP guidance document “Guidance for Assessing the Ecological Risks of PFAS to Threatened and Endangered Species at Aqueous Film Forming Foam Impacted Sites,” available for download at: https://www.serdp-estcp.org/Program-Areas/Environmental-Restoration/ER18-1614. This guidance provides pragmatic approaches for addressing PFAS ecological risks at AFFF-impacted sites, but is also applicable to sites impacted by other PFAS sources. Although a focus of the guidance is on Threatened and Endangered (T&E) species, the guidance is applicable to non-T&E species as well. In addition, the course will provide a hands-on demonstration of a customizable Microsoft Excel food web and wildlife exposure modeling tool to enable ecological risk assessors to apply the guidance and recommended exposure and effects models to site-specific ERAs. Model outputs consist of an evaluation of the potential for direct effects to aquatic or terrestrial communities and model-predicted concentrations in food webs and wildlife diet items. The ERA Model Tool will be provided in advance of the course so that attendees can follow along with demonstrations on their own laptops (optional).

Title: Tools for Evaluating Ecological Risks and Foodweb Modeling of Per- and Polyfluoroalkyl Substances

Presenter: Jennifer Arblaster, Geosyntec Consultants
Time: 1:00 PM CST on November 19, 2020

Ecological Risk Assessments (ERAs) for PFAS require specific data needs and tools, many of which have been historically lacking. Recently, under a Department of Defense Strategic Environmental Research and Development Program (SERDP) statement of need, a number of practicable tools for completing ERAs for PFAS were developed. This presentation will highlight two new tools available under SERDP: 1) Excel based foodweb modeling tools for aquatic and terrestrial foodwebs, and 2) a comprehensive set of wildlife screening criteria. To support refined-SLERA and baseline ERAs, SERDP Project ER18-1614 developed a foodweb modeling framework for aquatic and terrestrial foodwebs following a critical review of over 1000 bioaccumulation metrics for PFAS (e.g. bioconcentration, bioaccumulation, and biota-soil accumulation factors). The modeling framework has been developed into an Excel-based modeling tool where concentrations of PFAS in abiotic media can be input by users with minimal additional data needs, to facilitate foodweb modeling and risk characterization for wildlife. To support screening level ERAs, SERDP Project ER18-1653 developed screening levels for aquatic life (aquatic plants, invertebrates, fish, and amphibians) using the Great Lakes Initiative methodology, and for terrestrial plants, soil invertebrates, and terrestrial and aquatic wildlife (birds and mammals) following USEPA Ecological Soil Screening Levels methodology. Along with highlighting these new tools for PFAS ERAs, ongoing data gaps and research needs will be discussed.

Title: Evaluation of a Rapid Biosensor Tool for Measuring PAH Availability in Sediment

Presenters: Jason Conder, Geosyntec Consultants
Time: On Demand

Decades of research has shown that measuring freely dissolved PAH (Cfree) in sediment is superior to measurement of “total” concentrations of PAHs in sediment and sediment porewater, as Cfree is a much better predictor of bioavailability and toxicity to aquatic organisms. Passive sampling techniques and equilibrium partitioning (EqP) models (such as 1-carbon and 2-carbon models) have been used for measuring and predicting Cfree, respectively, but these techniques require weeks for analytical chemical measurements and subsequent data evaluation. This study evaluated the performance of a portable, field-deployable antibody-based PAH biosensor technique that can provide measurements of PAH Cfree within a matter of minutes using a small volume of sediment porewater. Four sediments with a wide range of PAHs (ΣPAH 2.4 to 307 mg/kg) derived from petroleum, creosote, and urban PAH sources were analyzed via bulk chemistry methods, exposed ex situ to polyethylene passive samplers, and compressed to yield a porewater sample that was analyzed via the biosensor. Mean ΣPAH Cfree, determined by the biosensor for the four sediments (3.1 to 55 µg/L) were within a factor of 1.1 (on average) compared to mean ΣPAH Cfree determined by the passive samplers (2.0 to 52 µg/L). All mean ΣPAH Cfree values differed by factor of 3 or less. In contrast, 1-carbon and 2-carbon EqP ΣPAH Cfree predictions overpredicted passive sampler-derived Cfree measurements by an average factor of 6.4 and 6.0, respectively. The biosensor was also useful in identifying sediments that are likely to be non-toxic to benthic invertebrates. In two of the four sediments, biosensor results of 20 and 55 µg/L exceeded a potential biosensor screening level of 10 µg/L (derived from prior research), indicating toxicity could not be ruled out. Toxic Units (TU) measured in these two sediments using the passive sampler Cfree results were also greater than the TU threshold of 1 (6.7 and 5.8, respectively), confirming the conclusions reached with the biosensor. In contrast, the other two sediments were identified as non-toxic by both the biosensor (biosensor results of 3.1 and 4.3 µg/L) and the passive sampler (TU of 0.039 and 0.34). These results indicate that the biosensor is a promising tool for rapid screening of sediments potentially-impacted with PAHs, and further evaluation of the biosensor with additional sediments is recommended.

Title: Pilot Scale Demonstration of Innovative Approaches to Measure Freely Dissolved Polychlorinated Biphenyls in Choccolocco Creek

Presenters: Alice Wang, Geosyntec Consultants
Time: On Demand

The measurement of freely-dissolved chemicals (Cfree) is a powerful approach for improving the assessment and management of sediment sites. This presentation will present an overview of a pilot scale demonstration of innovative approaches to measure freely-dissolved PCBs in the Choccolocco Creek portion of the Anniston PCB Site (Alabama, USA). Freely-dissolved PCBs were measured using a custom-modified approach using commercially available polyethylene passive samplers (SP3s). PCBs absorbed by the SP3s were quantified using an innovative approach measuring PCB homologues and Aroclors (instead of PCB congeners), and sampling kinetics were tracked using seven isotopically-labeled PCB congener Performance Reference Compounds (PRCs) added to each SP3 prior to deployment. SP3 were deployed for 35 days at two locations representing different hydrodynamic conditions (high-energy, low-energy) in Choccolocco Creek. At the high-energy location, SP3s were deployed in surface water, within the rocky substrate, and at the substrate-water interface using SCUBA divers. At the low-energy location, SP3 were deployed in surface water, within the soft sediment substrate, and the substrate-water interface using a push-pole device that allowed deployment of the SP3s from a vessel without the aid of divers. A sample of sediment was also collected and used for an ex situ Cfree measurement via agitation with an SP3 for 35 days. PRC results indicated that the deployment time period was sufficient for absorption of PCB analytes in situ. Measurement of PCBs via the homologue method indicated a detection frequency of 66%, and Cfree detection limits (0.1 pg/L on average) were similar to Cfree approaches that rely on the measurement of individual PCB congeners. In contrast, the Aroclor method was less sensitive. Only 25% of the Aroclor results yielded detectable values for the SP3s, and sum of the Cfree Aroclors for the samples (non-detect to 20 ng/L) was less than that of the sum of the Cfree homologues (3 to 48 ng/L). Overall, the pilot scale evaluation was successful and indicated that the approach for PCB homologues provides sensitive and versatile measurement capabilities for Cfree PCBs.

More Information

About the event: https://scicon2.setac.org/
About SETAC: https://www.setac.org/default.aspx
For consultation regarding risks associated with PFAS, contact Jason Conder at JConder@Geosyntec.com or Jennifer Arblaster at JArblaster@Geosyntec.com
Learn more about Jason: https://www.geosyntec.com/people/jason-conder
Learn more about Jennifer: https://www.geosyntec.com/people/jennifer-arblaster
Learn more about Alice: https://www.linkedin.com/in/alice-peiying-wang-188b8a13/