Indoor exposure to per- and polyfluoroalkyl substances (PFAS) in the childcare environment
By Guomao Zheng, Brandon E. Boor, Erika Schreder, Amina Salamova
December 10, 2019
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 and distribution 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 (PFCA) perfluoroalkyl sulfonates (PFSA), fluorotelomer alcohols (FTOH), perfluorooctane sulfonamides/perfluorooctane sulfonamidoethanols (FOSA/FOSE), and fluorotelomer acrylates/fluorotelomer methacrylates (FTAC/FTMAC) in the childcare environment and estimated children's exposure through dust ingestion. 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 (ΣPFAS) ranging from 8.1 to 3,700 ng/g and were dominated by the two neutral PFAS groups: ΣFTOH (n.d. – 3,100 ng/g) and ΣFOSA/FOSE (n.d. – 380 ng/g). The ionic PFAS were detected at lower concentrations and were dominated by 6:2 FTS and 8:2 FTS (median 12 and 5.8 ng/g, respectively). ΣPFAS concentrations in mats (1.6–600 ng/g) were generally an order of magnitude lower than in dust and were dominated by ΣFOSA/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% to the total PFAS intake, suggesting that exposure via dust to PFAS precursors may be an important contributor to overall PFAS exposure. This higher exposure to neutral PFAS is concerning considering that many neutral PFAS are the precursors of ionic PFAS with known toxic properties, such as PFOA.
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