Departmental Seminar

Abstract:

Per- and polyfluoroalkyl substances (PFAS) have raised significant concern due to their extensive use, widespread contamination, and environmental persistence. Most research has focused on “legacy” long-chain PFAS, however, in recent years, these legacy PFAS have been phased out in many countries, ultimately leading to short-chain PFAS becoming more prevalent in manufacturing and the environment. One specific short chain PFAS, perfluorohexanoic acid (PFHxA), has emerged as one of the most commonly detected PFAS in Florida waterbodies. Additionally, several studies have shown that PFHxA can bioaccumulate in aquatic organisms.  However, there is little knowledge on its bioaccumulation and effects in non-model fish and bivalves that contribute tremendous value to Florida's economy. To address this knowledge gap, we exposed two important Florida species, the Florida Bass (Micropterus salmoides) and the eastern oyster (Crassostrea virginica) to environmentally relevant concentrations of PFHxA and utilized transcriptomics to develop hypotheses on potentially toxicity pathways in these animals.  We followed these exposures with a larger set of exposure doses to examine bioaccumulation and depuration as well as sub-lethal toxicity. In oysters, pathways involved in the bivalve immune system function and apoptosis were altered at lower concentrations and lipid metabolism related pathways were altered at higher concentrations. Analysis of tissues for bioaccumulation indicated concentrations exceeding environmentally relevant concentrations were required for measureable bioaccumulation and there was rapid depuration following the exposures end.  In largemouth bass, similar pathways were disrupted indicating conservation of toxicity pathways in these two species.  However, bioaccumulation was noted at lower concentrations in the bass. Results from this study highlight the importance of examining the effects of emerging PFAS on commercially and recreationally important Florida species to inform regulators and stakeholders to make informed decision regarding the potential impacts of these chemicals.

Biography: 

Dr. Joe Bisesi earned his B.S. and M.S in biological sciences and his Ph.D. in Environmental Toxicology from Clemson University. He is currently the Associate Director of the UF/IFAS Center for Aquatic and Invasive Plants (CAIP) and an associate professor in the School of Forest, Fisheries, and Geomatic Sciences at the University of Florida. He also maintains affiliations with UF’s Center for Environmental and Human Toxicology, Water Institute, and Emerging Pathogens Institute. He is an aquatic toxicologist whose work focuses on examining both the beneficial and detrimental impacts of chemicals in aquatic environments in support of protecting human health and ecosystems in Florida. His work combines environmental analytical chemistry to characterize exposure and effects assessments in several aquatic species to gain insights on risk to humans and aquatic organisms from chemical exposures in water. His current research focuses on three specific areas: (1) Understanding the bioaccumulation and effects of emerging short chain PFAS on recreationally and commercially important fisheries in the state of Florida; (2) Examining the impacts of aquatic invasive species (plants and mussels) on infrastructure projects and developing environmentally sound chemical management strategies; (3) Utilizing wastewater based surveillance to understand population level consumption patterns of illicit drugs.