Superfund Research Program
Integrating Experimental and Field Studies to Understand PFAS Bioaccumulation and Impact in Aquatic Food Webs
Project Summary (2020-2025)
Per- and polyfluoroalkyl substances (PFAS) are chemicals that are of emerging concern because they are widely released into the environment, where they tend to be persistent and bioaccumulative. Some PFAS are associated with adverse health outcomes in people, and production of a limited number of them (e.g., PFOA and PFOS) has been phased out because of these concerns. However, there are approximately 5,000 PFAS, and there is considerable uncertainty regarding the human health and environmental safety of these compounds because most PFAS have never been tested. Because these compounds are routinely released into waterways that serve as sources of drinking water and nutrition via consumption of fish and aquatic wildlife, there is an immediate need to better understand their environmental fate and effects. As concerns about PFAS in the environment are beginning to grow, there are increasing reports of the presence of these compounds in water and in aquatic organisms, but our understanding of their bioaccumulation potential and toxicity to aquatic life is limited. This project specifically addresses concerns about the bioaccumulation and toxicity of PFAS in aquatic food webs. One major goal is to compare the accumulation of individual PFAS in a food web context by comparing aqueous uptake in primary producers (periphyton), primary consumers (mayflies), and secondary consumers (zebrafish) in the laboratory. A second major goal is to understand the potential for different compounds to move trophically in food webs by measuring the movement of different compounds from periphyton to mayflies to fish. Only by doing controlled studies in the laboratory can we systematically understand the bioaccumulation dynamics of different compounds based on their different chemical structures. The next major goal of this work is to compare the toxicity of different PFAS to zebrafish. While zebrafish are a recognized model for human health studies, this project utilizes the deep understanding of this species’ biology to explore the consequences of PFAS exposure to fish. The project is comparing the toxicity of individual PFAS in zebrafish using traditional toxicity approaches (exposures from water) but is unique in that it also assesses the potential for dietary PFAS exposures to contribute to toxicity because in nature, exposures in aquatic organisms are likely to derive from both water and dietary sources. Finally, these laboratory studies are complemented by field investigations of PFAS in local waterways and in the tissues of aquatic fish and wildlife. This latter aim is prompted by local PFAS contamination of a major watershed by a manufacturing plant and associated concerns about real-world exposures. Specifically, the project is measuring PFAS in fish and wildlife that are potential dietary exposure routes to these contaminants in people. Together, the project is providing much-needed information about the bioaccumulation, toxicity, and exposure profiles of PFAS in the aquatic environment.