Indoor exposure to per- and polyfluoroalkyl substances (PFAS) in the childcare environment

Per- and polyfluoroalkyl substances (PFAS) are widely used in stain-resistant carpets, rugs, and upholstery, as well as in waxes and cleaners, and are potential contaminants in the childcare environment. However, limited knowledge exists on the occurrence of PFAS in indoor environments, apart from residential homes. Here, we determined the occurrence and distribution of 37 neutral and ionic PFAS, including perfluoroalkyl carboxylates (PFCAs) perfluoroalkyl sulfonates (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer sulfonates (FTSs), perfluorooctane sulfonamides and perfluorooctane sulfonamidoethanols (FOSAs/FOSE5), and fluorotelomer acrylates and fluorotelomer methacrylates (FTACs/FTMAC5) in the childcare environment and estimated children's exposure through dust ingestion and dermal absorption. We analyzed dust and nap mats, a commonly used item in many childcares, from eight facilities located in the United States. Twenty-eight PFAS were detected in dust with total PFAS concentrations (Sigma PFAS) ranging from 8.1 to 3,700 ng/g and were dominated by the two neutral PFAS groups: Sigma FTOH (n.d. 3,100 ng/g) and IFOSA/FOSE (n.d. 380 ng/g). The ionic PFAS were detected at lower concentrations and were dominated by 6:2 FT'S and 8:2 FTS (median 12 and 5.8 ng/g, respectively). Sigma FAS concentrations in mats (1.6-600 ng/g) were generally an order of magnitude lower than in dust and were dominated by Sigma FOSA/FOSE concentrations (n.d. - 220 ng/g). Daily intake of neutral PFAS in the childcare environment via dust ingestion was estimated at 0.20 ng/kg bw/day and accounted for 75% of the Sigma FAS intake. This higher exposure to neutral PFAS is concerning considering that many neutral PFAS are the precursors of toxic ionic PFAS, such as PFOA. (C) 2019 Elsevier Ltd. All rights reserved.