In vitro modeling of the post-ingestion bioaccessibility of per- and polyfluoroalkyl substances sorbed to soil and house dust - SOT
Citation:
Parker, B., E. Valentini, S. Graham, AND J. Starr. In vitro modeling of the post-ingestion bioaccessibility of per- and polyfluoroalkyl substances sorbed to soil and house dust - SOT. Society of Toxicology Annual Meeting, Nashville, TN, March 19 - 23, 2023.
Impact/Purpose:
Soils and house dusts are sorbents that can function as sinks for many regulated organic compounds. Since children ingest relatively large amounts of soil and dust, it is important to understand the factors that determine uptake of sorbed organic toxicants when estimating the toxicity of these chemicals to children. Considering ingestion of soil or house dusts with sorbed organics, bioaccessibility is defined as the percent of contaminant desorption from the soil or dust. In this study we develop an in vitro post ingestion bioaccessibility model for Per- and polyfluoroalkyl substances (PFAS) sorbed to soils and house dusts. The results show that bioaccessibility depends on the PFAS chain length, number of branches, and the carbon content of the soil or house dust. The data will be useful for PFAS risk assessments and those studying children's health exposure factors such as Office of Children's Health Protection
Description:
Per- and polyfluoroalkyl substances (PFAS) are regularly found in soils and dusts, both of which are consumed by children at relatively high amounts. However, there is little data available to model bioaccessibility of PFAS in soils and dusts when consumed, or to describe how the physicochemical properties of PFAS and soils/dusts affect bioaccessibility. In the current study, in vitro assays were conducted to calculate bioaccessibility of fourteen PFAS in 33 sets of soils and dusts. Bioaccessibility assays were conducted with and without a carbon fiber ‘sink’, which was used to simulate the movement of PFAS across the intestine. Multiple linear regressions with backward elimination were used to model the behavior of PFAS sorbed to soils and dusts. A segmented model found that PFAS chain length, number of branches, and percent total organic carbon (% TOC) were the best predictors of bioaccessibility. In general, PFAS had significantly greater bioaccessibility in soils relative to dusts. The addition of a carbon sink also significantly increased bioaccessibility by as much as 10.8% in soils and 20.3% in dusts. Using a segmented model resulted in 78.0-88.9% of the variability in PFAS bioaccessibility accounted for. The results from this study indicate that PFAS bioaccessibility in soils and dusts can be predicted and could be used to inform risk assessment models in the future.
