April 9, 2020 11 am CDT
Development of PFAS Toxicity Reference Values in Amphibians for use in Ecological Risk Assessments of AFFF-Contaminated Sites” by Dr. Marisol Sepulveda
The primary goal of this project is to develop per- and polyfluoroalkyl substances (PFAS) toxicity reference values (TRVs) for amphibians. TRVs are needed to evaluate risk for amphibians native to the U.S., including northern leopard frogs, bullfrogs, American toads, and tiger salamanders, in areas contaminated by aqueous film forming foam (AFFF) and PFAS mixtures, including some Department of Defense (DoD) lands. Larvae and juveniles were exposed to PFAS of different chain length and functional groups. Results showed that PFAS uptake and elimination rates are fast (48 hours to reach steady state). This is the fastest accumulation rate reported for a developing vertebrate. Effects on growth and development were shown to be dependent on PFAS, species, life-stage, and exposure-route. We found that although PFOS bioaccumulated two orders of magnitude more than some other PFAS, it is not necessarily more toxic. Altered growth and development were observed at 10 parts per billion (ppb), the lowest concentration tested. In addition to the above results, this presentation will cover testing PFAS mixtures recreated using data from AFFF-impacted sites under semi-natural and laboratory conditions.
Guidance for Assessing the Ecological Risks of Threatened and Endangered Species at Aqueous Film Forming Foam (AFFF)-Impacted Sites by Dr. Jason Conder
This project supports SERDP’s efforts to maintain DoD execution of mission-related activities by providing effective, science-based guidance for promoting the recovery of understory plant communities. Our work combined intensive long-term monitoring of plant populations with field-based experiments deployed over three separate installations. We tracked 25 plant species by conducting long-term sampling at 192 plots from 18 sites at Fort Bragg in North Carolina, 12 sites at Fort Stewart in Georgia, and 18 sites at Savannah River Site in South Carolina. We evaluated whether (1) management activities (e.g., seed additions, prescribed fire, tree thinning) could be used to maximize plant population and community recovery, (2) plant populations persisted as self-sustaining populations for many years after recovery was initiated, and (3) management activities could maximize the likelihood that populations would spread once established, resulting in self-propagating recovery efforts. Our long-term data provides a powerful means to evaluate how seasonal climatic variation affect plant populations. The presentation will describe the management activities that maximize the establishment, persistence, and spread of plants in longleaf pine ecosystems, and will highlight how seasonal climatic variation may play a critical, yet unappreciated, role in guiding recovery of plant communities on DoD lands.