CAREER: Transformation potential of per- and polyfluoroalkyl substances (PFAS) in drinking water distribution systems

Per- and polyfluoroalkyl substances (PFAS) are fluorinated organic chemical contaminants that are commonly referred to as forever chemicals due to their persistence, stability, and resistance to natural environmental degradation processes. During the last two decades, PFAS have been increasingly detected in surface water systems (lakes and rivers) and groundwater aquifers which serve as sources of drinking water for many communities throughout the United States.

In addition, many PFAS can be transformed through abiotic and biotic pathways in natural and engineered water systems to produce toxic perfluoroalkyl acids (PFAAs), including perfluorooctanoic acid (PFOA). There is a critical need for new data and knowledge to advance the fundamental understanding of the fate, transport, and reactivity of PFAS in drinking water systems.

The overarching goal of this CAREER project is to investigate and evaluate the abiotic and biotic transformations of PFAS in drinking water distribution systems (DWDS) as the treated water transits through the distribution systems to customers’ taps. To advance this goal, the Principal Investigator proposes to integrate field studies of PFAS transformations in selected DWDS with controlled laboratory and pilot scale experiments.

The successful completion of this project will benefit society through the generation of new data and fundamental knowledge to advance the design of engineering solutions and policy recommendations to address and mitigate PFAS drinking water contamination. Additional benefits to society will be achieved through student education and training including the mentoring of two graduate students at George Mason University.

Many drinking water distribution systems (DWDS) exhibit environmental conditions comparable to those of natural aquatic systems in which the transformations of PFAS compounds and precursors to toxic perfluoroalkyl acids (PFAAs), including perfluorooctanoic acid (PFOA), have been observed. In addition, the components of DWDS (e.g., pipes, tanks, and water towers) can serve as substrates for the accumulation of scales/sediments and the formation of biofilms that cause/catalyze the abiotic/biotic transformations of dissolved contaminants in these systems.

This CAREER project will test the hypothesis that PFAS transformations in DWDS are primarily mediated by the biotic transformations of PFAS compounds and precursors that accumulate in their scales and sediment biofilms. To test this hypothesis, the Principal Investigator (PI) proposes to evaluate and characterize the chemical and microbial processes controlling PFAS transformations in DWDS with a focus on storage facilities in the Mid-Atlantic region of the United States.

The specific objectives of the research are to 1) investigate PFAS partitioning and transformations in drinking water storage facilities and develop methods and infrastructure for the design of controlled experiments to generate fundamental insights; 2) evaluate the effects of storage tank/sediment materials and environmental parameters on PFAS partitioning and transformations in drinking water storage facilities; and 3) evaluate the effect of treatment residuals on PFAS transformations in the biofilms of drinking water storage facilities. The successful completion of this project has the potential for transformative impact through the generation of new fundamental knowledge to advance the design and implementation of engineering solutions to minimize and mitigate PFAS contamination in drinking water storage facilities and distribution systems.

To implement the educational and outreach activities of this CAREER project, the PI proposes to leverage existing programs and resources at George Mason University (GMU) to carry out curricular research on chemistry education to support learning and success for community college transfer, non-traditional and traditional students in environmental engineering (EE). More specifically, the PI proposes to 1) investigate the impact of student chemistry preparation, attitudes, and demographics on performance and interest in EE); 2) evaluate correlations between student performance in chemistry and mastery of concepts in introductory EE courses; and 3) use the knowledge gained from this research to design lessons to remediate student chemistry preparation gaps and prepare students for the successful completion of EE undergraduate education at GMU.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.