Summary

Per- and polyfluoroalkyl substances (PFAS) are an emerging class of water pollutants that cause serious environmental and health concerns. More than 9,000 PFAS have been identified, with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) and several of their structural analogues being the most used and studied. Due to their wide use in industry, the military, and fire protection, PFAS have contaminated most of the world's bodies of water. Recent studies indicate a clear linkage between long-term PFAS exposure and adverse effects on the body's immune, endocrine, metabolic, and reproductive systems (e.g., fertility and pregnancy complications) and an increased risk of cancer. Most PFAS samples are analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). However, the costs, footprint, power requirements, and time-consuming sample preparation and concentration processes often associated with LC- MS/MS limit the deployment of this technology outside of formal laboratory settings. It is, therefore, imperative to develop and commercialize a rapid, simple, and low-cost detection platform that is much more suited for the quick, onsite, and ultralow-level detection of PFAS. While several chemical sensor technologies, such as those based on fluorescence modulation, have been developed for the detection of PFAS, most of these platforms are still far from sufficient for potable water analysis regarding either sensitivity (low 4 pptr levels), or selectivity against the common chemicals, especially detergents. The ability to gain a much more detailed understanding of PFAS contamination on a regional basis, especially with respect to smaller communities, is also complicated because most public utilities and local enforcement agencies do not have access to the costly analytical equipment required to detect PFAS at environmentally- relevant concentrations. Consequently, these communities collect and ship samples to an EPA-certified laboratory for analysis. However, it often takes weeks and even months before any test results become available, leading to high stress levels and unreasonable wait times for the individual users and, quite likely, countless others. As is evident, the technical capability to determine the range and scope of PFAS contamination and to assess the efficacy of treatment methods used to remediate impacted aquatic systems and ensure contamination-free drinking and process water supply for communities across the country demands significant improvements in the availability to detect PFAS at the point of need, (i.e., on-site). Stated differently, there is an urgent need for a technique that allows quick and frequent detection and does not require access to conventional analytical methods and far away laboratories. To this end, our research and development team will develop a field- portable measurement system that couples molecular-based fluorescent sensors, solid phase extraction (F/SPE), and artificial intelligence to tackle the global need for an easy-to-use technology that can be applied on-site for rapid, ultrasensitive PFAS detection. Developing our innovative sensor system as an invaluable solution in meeting this need requires input from the intended users, including government agencies monitoring regulatory compliance, public utilities providing safely treated water to community members, and industrial partners working on cleanup efforts to protect aquatic environmental systems. Our plan emphasizes the extensive involvement of representatives from each of these domains who will bring their unique perspectives in a user-centered iterative design process to ensure the final product will enhance the water and wastewater industry's ability to confront challenges related to PFAS head- on. This work's broader impact is ensuring that individual users, including off-grid and small communities, have reliable methods to ensure clean and contamination-free drinking water.