Fang Mingliang, Stapleton Heather M
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Environ Sci Technol. 2014 Nov 18;48(22):13323-30. doi: 10.1021/es503918m. Epub 2014 Nov 5.
Exposure to house dust is a significant source of exposure to flame retardant chemicals (FRs), particularly in the US. Given the high exposure there is a need to understand the bioaccessibility of FRs from dust. In this study, Tenax beads (TA) encapsulated within a stainless steel insert were used as an adsorption sink to estimate the dynamic absorption of a suite of FRs commonly detected in indoor dust samples (n = 17), and from a few polyurethane foam samples for comparison. Organophosphate flame retardants (OPFRs) had the highest estimated bioaccessibility (∼ 80%) compared to brominated compounds (e.g., PBDEs), and values generally decreased with increasing Log K(ow), with <30% bioaccessibility measured for BDE209. These measurements were in very close agreement with reported PBDE bioavailability measures from an in vivo rat exposure study using indoor dust. The bioaccessibility of very hydrophobic FRs (Log K(ow) > 6) in foam was much less than that in house dust, and increasing bioaccessibility was observed with decreasing particle size. In addition, we examined the stability of more labile FRs containing ester groups (e.g., OPFRs and 2-ethylhexyl-tetrabromo-benzoate (EH-TBB)) in a mock-digestive fluid matrix. No significant changes in the OPFR concentrations were observed in this fluid; however, EH-TBB was found to readily hydrolyze to tetrabromobenzoic acid (TBBA) in the intestinal fluid in the presence of lipases. In conclusion, our study demonstrates that the bioaccessibility and stability of FRs following ingestion varies by chemical and sample matrix and thus should be considered in exposure assessments.
接触室内灰尘是接触阻燃化学品（FRs）的一个重要来源，在美国尤其如此。鉴于接触程度较高，有必要了解灰尘中FRs的生物可及性。在本研究中，将封装在不锈钢插入件中的Tenax珠（TA）用作吸附阱，以估计在室内灰尘样品（n = 17）以及一些聚氨酯泡沫样品中常见的一组FRs的动态吸附情况，以便进行比较。与溴化化合物（如多溴二苯醚）相比，有机磷酸酯阻燃剂（OPFRs）的估计生物可及性最高（约80%），其值通常随Log K(ow)的增加而降低，BDE209的生物可及性<30%。这些测量结果与一项使用室内灰尘的大鼠体内暴露研究报告的多溴二苯醚生物利用度测量结果非常一致。泡沫中疏水性很强的FRs（Log K(ow) > 6）的生物可及性远低于室内灰尘中的生物可及性，并且随着粒径减小，生物可及性增加。此外，我们在模拟消化液基质中研究了含有酯基的更不稳定的FRs（如OPFRs和2-乙基己基四溴苯甲酸酯（EH-TBB））的稳定性。在这种液体中未观察到OPFR浓度有显著变化；然而，发现EH-TBB在存在脂肪酶的肠液中容易水解为四溴苯甲酸（TBBA）。总之，我们的研究表明，摄入后FRs的生物可及性和稳定性因化学物质和样品基质而异，因此在暴露评估中应予以考虑。
