title: Using paired soil and house dust samples in an in vitro assay to assess the post ingestion bioaccessibility of sorbed fipronil.
abstract: For children, ingestion of soils and house dusts can be an important exposure pathway for regulated organic compounds. Following ingestion, the extent to which compounds desorb and become bioaccessible is a critical determinant of systemic adsorption. We characterized the physicochemical properties of 37 soil and house dust pairs collected during a national survey of United States homes. For each sample, we measured the bioaccessibility of fipronil, a phenylpyrazole insecticide using an in vitro, three- compartment digestive system, then modeled the physicochemical predictors of fipronil bioaccessibility. The properties of the soils and dusts were not correlated and percent carbon was the only significant predictor of bioaccessibility for both soils (p<0.001) and dusts (p<0.001). The carbon content of the soils (3.1±2.4%) was lower than that of the dusts (18.6±6.9%) Due to the lower carbon content, soil sorbed fipronil was more bioaccessible than dust sorbed fipronil. However, the slope of the bioaccessibility carbon regression line was steeper for the soils than for the house dusts. This suggested that, for soils having carbon percentages greater than those in this study, fipronil bioaccessibility may be less than that of house dusts having equal carbon content.
authors.affiliation: United States Environmental Protection Agency National Exposure Research Laboratory, Research Triangle Park, NC 27711, USA. Electronic address: starr.james@epa.gov.
authors.forename: James M
authors.initials: JM
authors.lastname: Starr
authors.affiliation: Oak Ridge Institute for Science and Education Fellow at the United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27711, USA.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Li
authors.affiliation: United States, Environmental Protection Agency Office of Air Quality Planning and Standards, Research Triangle Park, NC 27711, USA.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Graham
authors.affiliation: United States Environmental Protection Agency National Exposure Research Laboratory, Research Triangle Park, NC 27711, USA.
authors.forename: Karen D
authors.initials: KD
authors.lastname: Bradham
authors.affiliation: United States Environmental Protection Agency National Exposure Research Laboratory, Research Triangle Park, NC 27711, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Stout Ii
authors.affiliation: United States Environmental Protection Agency National Exposure Research Laboratory, Las Vegas, NV 89119, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Williams
authors.affiliation: Student Services Contractor at the United States Environmental Protection Agency National Exposure Research Laboratory, Las Vegas, NV 89119, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Sylva
mesh_terms: D001682:Biological Availability; D002244:Carbon / Q000493:pharmacokinetics; D004391:Dust; D006801:Humans; D007306:Insecticides / Q000493:pharmacokinetics*; D011720:Pyrazoles / Q000493:pharmacokinetics*; D012987:Soil
chemical_list: D004391:Dust; D007306:Insecticides; D011720:Pyrazoles; D012987:Soil; D002244:Carbon; C082360:fipronil
keywords: Bioaccessibility; Fipronil; House dusts; Ingestion; Soils