Per- and Polyfluoroalkyl Substances in Dust Collected from Residential Homes and Fire Stations in North America

Abstract

Over the past few years, human exposure to per- and polyfluoroalkyl substances (PFAS) has garnered increased attention. Research has focused on PFAS exposure via drinking water and diet, and fewer studies have focused on exposure in the indoor environment. To support more research on the latter exposure pathway, we conducted a study to evaluate PFAS in indoor dust. Dust samples from 184 homes in North Carolina and 49 fire stations across the United States and Canada were collected and analyzed for a suite of PFAS using liquid and gas chromatography–mass spectrometry. Fluorotelomer alcohols (FTOHs) and di-polyfluoroalkyl phosphoric acid esters (diPAPs) were the most prevalent PFAS in both fire station and house dust samples, with medians of approximately 100 ng/g dust or greater. Notably, perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate, perfluorononanoic acid, and 6:2 diPAP were significantly higher in dust from fire stations than from homes, and 8:2 FTOH was significantly higher in homes than in fire stations. Additionally, when comparing our results to earlier published values, we see that perfluoroalkyl acid levels in residential dust appear to decrease over time, particularly for PFOA and PFOS. These results highlight a need to better understand what factors contribute to PFAS levels in dust and to understand how much dust contributes to overall human PFAS exposure.

Per- and polyfluoroalkyl substances (PFAS) and total fluorine in fire station dust

“…In fact, the dust samples from fire station living areas in our study all had lower detected median levels, and order(s) of magnitude lower maximum levels, of PFAAs compared to dust collected in living areas of 49 fire stations in the US and Canada (the authors did not measure the same PFAA precursors as we did) (Table S3). 30 Thus, the nonexistent or otherwise rare use of PFAS-containing AFFF by the fire stations in our study may be one reason for the lower PFAA dust levels than the fire stations in that other study, which further motivates shifts towards firefighting products that do not contain any PFAS and that are only used sparingly.…”

“…For PFAAs, concentrations in the fire station living room dust samples were generally lower than previous studies of dust in U.S. homes or offices, although these environments are not directly comparable (Table S3). 30,47,[64][65][66][67][68][69] Only one living room in this study had carpet, which is an important source of PFAAs indoors. 13,47,67 In addition, those studies did not measure the three most frequently detected chemicals in this study's samples-N-EtFOSAA, 6:2 FtS, and 8:2 FtS-which were found at higher concentrations than in previous European studies.…”

“…29 One recent study found that dust collected in living areas of fire stations had a fifteen times higher median level of perfluorooctane sulfonate (PFOS) and three times higher median level of PFHxS than homes, with the sources thought to include their use as components in AFFF and stain-resistant carpet burned during fires. 30 However, most previous studies have focused on firefighter exposures to PFAS while out fighting fires or training, not potential sources of PFAS contamination specific to the fire station itself.…”

Understanding semi-volatile organic compounds in indoor dust

“…[20][21][22] PFASs in indoor dust have been reported by a few studies internationally with a large variety in concentrations ranging from below the detection limit to hundreds of ng/g, or even µg/g. 3,[23][24][25][26][27][28][29] PFASs that were frequently determined at high concentrations in dust are perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and fluorotelomer alcohols (6:2 FTOH, 8:2 FTOH). 2 The large difference between concentrations of PFASs in dust in different regions is associated with their presence in personal consumer products and the usage of household products or materials in addition to discrepancies of dust sampling methods and locations.…”

“…4,30 Some of the PFASs in indoor dust data up to 2017 have been summarized in the review by Lucattini et al 3 Notably, more research has been conducted to address the presence of indoor dust and its implications to human exposure to PFAS in recent years. [23][24][25][26][27][28][29] For example, Winkens, et al 23 investigated 65 floor dust samples collected from children's bedrooms in Finland for 62 PFAS analytes. The dust samples were dominated by polyfluoroalkyl phosphoric acid esters and FTOHs while five perfluoroalkyl carboxylic acids and PFOS were detected in more than half of the samples in addition to PFOA median concentration of 5.26 ng/g.…”