title: In vitro assessment of the bioaccessibility of brominated flame retardants in indoor dust using a colon extended model of the human gastrointestinal tract.
abstract: An in vitro colon extended physiologically based extraction test (CEPBET) which incorporates human gastrointestinal tract (GIT) parameters (including pH and chemistry, solid-to-fluid ratio, mixing and emptying rates) was applied for the first time to study the bioaccessibility of brominated flame retardants (BFRs) from the 3 main GIT compartments (stomach, small intestine and colon) following ingestion of indoor dust. Results revealed the bioaccessibility of γ-HBCD (72%) was less than that for α- and β-isomers (92% and 80% respectively) which may be attributed to the lower aqueous solubility of the γ-isomer (2 μg L⁻¹) compared to the α- and β-isomers (45 and 15 μg L⁻¹ respectively). No significant change in the enantiomeric fractions of HBCDs was observed in any of the studied samples. However, this does not completely exclude the possibility of in vivo enantioselective absorption of HBCDs, as the GIT cell lining and bacterial flora--which may act enantioselectively--are not included in the current CE-PBET model. While TBBP-A was almost completely (94%) bioaccessible, BDE-209 was the least (14%) bioaccessible of the studied BFRs. Bioaccessibility of tri-hepta BDEs ranged from 32-58%. No decrease in the bioaccessibility with increasing level of bromination was observed in the studied PBDEs.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Assiut University, 71526 Assiut, Egypt. mae_abdallah@yahoo.co.uk
authors.forename: Mohamed Abou-Elwafa
authors.initials: MA
authors.lastname: Abdallah
authors.forename: Emma
authors.initials: E
authors.lastname: Tilston
authors.forename: Stuart
authors.initials: S
authors.lastname: Harrad
authors.forename: Chris
authors.initials: C
authors.lastname: Collins
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis* / Q000706:statistics & numerical data; D004391:Dust / Q000032:analysis*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005411:Flame Retardants / Q000032:analysis / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000378:metabolism*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological
chemical_list: D004391:Dust; D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers