PFAS in Building MaterialsWater and air in urban areas are contaminated with neutral and ionic PFAS, however sources of and contributions to this contamination are poorly known. We investigated exterior building materials as a source of PFAS release into the environment and estimated the mass of PFAS used in exterior surfaces of various building archetypes.
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Project 1:
Characterizing and Quantifying PFAS in Exterior Building Materials
We hypothesized that building materials and products, used to reduce deterioration due to weathering, are likely sources of per- and polyfluoroalkyl substances (PFASs) to the environment. To test this hypothesis, three categories of outdoor products sold on the Canadian market, namely outdoor textiles, paints and sealants, were characterized for total organofluorine (TOF) using 19F nuclear magnetic resonance (19F NMR) and individual PFAS by liquid chromatography-high resolution mass spectrometry (LC-HRMS) and gas chromatography-mass spectrometry (GC-MS).
Results:
Results:
- 19F NMR revealed large variations in TOF concentrations and compositions between these products. Specifically, the TOF content ranged from 0.3-74.0, 0.1-42, and 0.6-2500 µmol/g in outdoor textiles, paints and sealants, respectively.
- The TOF in textiles was composed of three types of side-chain fluorinated polymers (SCFPs), including those derived from 6:2 fluorotelomers (FTs), 8:2 FTs, and perfluorobutane sulfonyl fluoride (PBSF).
- The TOF in paints consisted of two kinds of nonpolymers, including those with an aromatic-CF3 group and derived from 6:2 FTs, while those in sealants had both SCFPs and nonpolymers: SCFPs derived from 6:2 FTs, nonpolymers with an aromatic-CF3 group and those derived from 6:2 FTs and PBSF.
- LC-HRMS results for paints and sealants showed the dominance of three 6:2 FTs, including two 6:2 FT phosphate esters (PAPs) and one 6:2 FT pyrophosphate, which constituted 23–61% of the TOF, indicating the presence of additional unidentified 6:2 FTs.
- GC-MS analysis is ongoing to identify 6:2 FTs in these products. Weathering experiments involving exposure to UV radiation in a chamber showed that two textiles with PBSF-derived SCFPs, one paint with nonpolymeric 6:2 FTs, and one sealant containing 6:2 FT SCFPs all released short-chain perfluoroalkyl carboxylates or sulfonates (PFCAs/PFSAs).
- These results support the hypothesis that outdoor textiles, paints and sealants are not only significant pools of polymeric and nonpolymeric PFAS, but also could be significant sources of short-chain mobile PFCAs/PFSAs to the environment.
Project 2:
Estimating the Mass of PFAS in building materials
Water and air in urban areas contain elevated levels of neutral and ionic per- and polyfluoroalkyl substances (PFAS), however sources of and contributions to these levels are poorly known. We investigated exterior building materials as a source of PFAS release into the environment and estimated the mass of PFAS used in exterior surfaces of various building archetypes. Based on our testing of total fluorine and organic fluorine using Particle-Induced Gamma-Ray Spectroscopy (PIGE), Fluorine-19 Nuclear Magnetic Resonance Spectroscopy (F-NMR), Liquid Chromatography- High Resolution Mass Spectrometry (LC-HRMS), and Gas Chromatography- Mass Spectrometry (GC-MS), PFAS is found in some building materials such as paints, sealants, and textiles used in exterior applications.
Based on our PIGE calculations, 52% of exterior paints and sealants on the North American market contain PFAS. We estimated the mass of PFAS that could be used in exterior surfaces of new buildings prior to weathering.To calculate the mass of PFAS used in archetypal residential and commercial buildings, we first obtained architectural drawings for several building types in the United States and Canada and then calculated the surface areas of all exterior materials that could contain or be coated in a material made with PFAS.
To estimate the mass of PFAS in the building products we used the 10th, 50th and 90th percentiles of total F concentrations for product samples with detectable total F (µmol F/g wet weight) measured by PIGE. For example, we estimated that a large, three story house with a total floor area of 700 m2 coated with products in the 10th, 50th and 90th percentiles would have 57, 91 and 342 g of PFAS, on its surface. When thousands of new homes and commercial buildings are built yearly, these exterior building materials may be a significant source of PFAS in the environment.
Based on our PIGE calculations, 52% of exterior paints and sealants on the North American market contain PFAS. We estimated the mass of PFAS that could be used in exterior surfaces of new buildings prior to weathering.To calculate the mass of PFAS used in archetypal residential and commercial buildings, we first obtained architectural drawings for several building types in the United States and Canada and then calculated the surface areas of all exterior materials that could contain or be coated in a material made with PFAS.
To estimate the mass of PFAS in the building products we used the 10th, 50th and 90th percentiles of total F concentrations for product samples with detectable total F (µmol F/g wet weight) measured by PIGE. For example, we estimated that a large, three story house with a total floor area of 700 m2 coated with products in the 10th, 50th and 90th percentiles would have 57, 91 and 342 g of PFAS, on its surface. When thousands of new homes and commercial buildings are built yearly, these exterior building materials may be a significant source of PFAS in the environment.
Project 3:
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Our preliminary weathering results showed that under the influence of UV, the surface chemistry of PFAS coatings on surfaces such as tile changes by increasing the abundance of mobile and potentially harmful short-chained PFAS. These results are still on their way. Stay Tuned... |