Abstract:

While elevated levels of per- and polyfluoroalkyl substances (PFAS) are frequently observed in water and air samples collected from urban environments, their routes of introduction are poorly described. One potential route is through the use of PFAS in building materials. Here, we investigated exterior building materials as a source of PFAS release into the environment by estimating the mass of PFAS on the exterior surfaces of 50 houses from Toronto. Elevated levels of total fluorine (total F) were detected in approximately 60% of paints, sealants, caulking and textiles using Particle-Induced Gamma-Ray Emission (PIGE) Spectroscopy. Subsequent testing using Fluorine Nuclear Magnetic Resonance (19F-NMR), Liquid Chromatography coupled to High Resolution Mass Spectrometry (LC-HRMS), and Gas Chromatography coupled to Mass Spectrometry (GC-MS), confirmed the presence of PFAS in a subset of these products. To estimate the mass of PFAS that could enter the environment from these materials, we categorized exterior building materials into paints, sealants or caulking made with PFAS. We then calculated the 10th, 50th and 90th percentiles of total fluorine concentrations for product samples with detectable total F measured by PIGE (µmol F/g dry weight). For example, one of the largest residential houses examined, with a floor area of 700 m^2, contained 7, 91 and 342 g of PFAS in coatings on exterior surfaces for the 10th, 50th and 90th percentiles, respectively. With over 334,000 housing units under construction in Canada in 2022, exterior building materials may be a significant source of PFAS in the surrounding environment.