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Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size
Inhalation of halogenated flame-retardants (HFRs) released from consumer products is an important route of exposure. However, not all airborne HFRs are respirable, and thus interact with vascular membranes within the gas exchange (alveolar) region of the lung. HFRs associated with large (>4 µm),...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451958/ https://www.ncbi.nlm.nih.gov/pubmed/28486433 http://dx.doi.org/10.3390/ijerph14050507 |
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author | La Guardia, Mark J. Schreder, Erika D. Uding, Nancy Hale, Robert C. |
author_facet | La Guardia, Mark J. Schreder, Erika D. Uding, Nancy Hale, Robert C. |
author_sort | La Guardia, Mark J. |
collection | PubMed |
description | Inhalation of halogenated flame-retardants (HFRs) released from consumer products is an important route of exposure. However, not all airborne HFRs are respirable, and thus interact with vascular membranes within the gas exchange (alveolar) region of the lung. HFRs associated with large (>4 µm), inhalable airborne particulates are trapped on the mucosal lining of the respiratory tract and then are expelled or swallowed. The latter may contribute to internal exposure via desorption from particles in the digestive tract. Exposures may also be underestimated if personal activities that re-suspend particles into the breathing zone are not taken into account. Here, samples were collected using personal air samplers, clipped to the participants’ shirt collars (n = 18). We observed that the larger, inhalable air particulates carried the bulk (>92%) of HFRs. HFRs detected included those removed from commerce (i.e., polybrominated diphenyl ethers (Penta-BDEs: BDE-47, -85, -100, -99, and -153)), their replacements; e.g., 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB or EH-TBB); bis(2-ethylhexyl) 3,4,5,6-tetrabromophthalate (TBPH or BEH-TEBP) and long-produced chlorinated organophosphate-FRs (ClOPFRs): tris(2-chloroethyl)phosphate (TCEP), tris(1-chloro-2-propyl)phosphate (TCPP or TCIPP), and tris(1,3-dichloro-2-propyl)phosphate (TDCPP or TDCIPP). Our findings suggest estimates relying on a single exposure route, i.e., alveolar gas exchange, may not accurately estimate HFR internal dosage, as they ignore contributions from larger inhalable particulates that enter the digestive tract. Consideration of the fate and bioavailability of these larger particulates resulted in higher dosage estimates for HFRs with log K(oa) < 12 (i.e., Penta-BDEs and ClOPFRs) and lower estimates for those with log K(oa) > 12 (i.e., TBB and TBPH) compared to the alveolar route exposure alone. Of those HFRs examined, the most significant effect was the lower estimate by 41% for TBPH. The bulk of TBPH uptake from inhaled particles was estimated to be through the digestive tract, with lower bioavailability. We compared inhalation exposure estimates to chronic oral reference doses (RfDs) established by several regulatory agencies. The U.S. Environmental Protection Agency (EPA) RfD levels for several HFRs are considered outdated; however, BDE-99 levels exceeded those suggested by the Dutch National Institute for Public Health and the Environment (RIVM) by up to 26 times. These findings indicate that contributions and bioavailability of respirable and inhalable airborne particulates should both be considered in future risk assessments. |
format | Online Article Text |
id | pubmed-5451958 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-54519582017-06-05 Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size La Guardia, Mark J. Schreder, Erika D. Uding, Nancy Hale, Robert C. Int J Environ Res Public Health Article Inhalation of halogenated flame-retardants (HFRs) released from consumer products is an important route of exposure. However, not all airborne HFRs are respirable, and thus interact with vascular membranes within the gas exchange (alveolar) region of the lung. HFRs associated with large (>4 µm), inhalable airborne particulates are trapped on the mucosal lining of the respiratory tract and then are expelled or swallowed. The latter may contribute to internal exposure via desorption from particles in the digestive tract. Exposures may also be underestimated if personal activities that re-suspend particles into the breathing zone are not taken into account. Here, samples were collected using personal air samplers, clipped to the participants’ shirt collars (n = 18). We observed that the larger, inhalable air particulates carried the bulk (>92%) of HFRs. HFRs detected included those removed from commerce (i.e., polybrominated diphenyl ethers (Penta-BDEs: BDE-47, -85, -100, -99, and -153)), their replacements; e.g., 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB or EH-TBB); bis(2-ethylhexyl) 3,4,5,6-tetrabromophthalate (TBPH or BEH-TEBP) and long-produced chlorinated organophosphate-FRs (ClOPFRs): tris(2-chloroethyl)phosphate (TCEP), tris(1-chloro-2-propyl)phosphate (TCPP or TCIPP), and tris(1,3-dichloro-2-propyl)phosphate (TDCPP or TDCIPP). Our findings suggest estimates relying on a single exposure route, i.e., alveolar gas exchange, may not accurately estimate HFR internal dosage, as they ignore contributions from larger inhalable particulates that enter the digestive tract. Consideration of the fate and bioavailability of these larger particulates resulted in higher dosage estimates for HFRs with log K(oa) < 12 (i.e., Penta-BDEs and ClOPFRs) and lower estimates for those with log K(oa) > 12 (i.e., TBB and TBPH) compared to the alveolar route exposure alone. Of those HFRs examined, the most significant effect was the lower estimate by 41% for TBPH. The bulk of TBPH uptake from inhaled particles was estimated to be through the digestive tract, with lower bioavailability. We compared inhalation exposure estimates to chronic oral reference doses (RfDs) established by several regulatory agencies. The U.S. Environmental Protection Agency (EPA) RfD levels for several HFRs are considered outdated; however, BDE-99 levels exceeded those suggested by the Dutch National Institute for Public Health and the Environment (RIVM) by up to 26 times. These findings indicate that contributions and bioavailability of respirable and inhalable airborne particulates should both be considered in future risk assessments. MDPI 2017-05-09 2017-05 /pmc/articles/PMC5451958/ /pubmed/28486433 http://dx.doi.org/10.3390/ijerph14050507 Text en © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article La Guardia, Mark J. Schreder, Erika D. Uding, Nancy Hale, Robert C. Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size |
title | Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size |
title_full | Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size |
title_fullStr | Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size |
title_full_unstemmed | Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size |
title_short | Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size |
title_sort | human indoor exposure to airborne halogenated flame retardants: influence of airborne particle size |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451958/ https://www.ncbi.nlm.nih.gov/pubmed/28486433 http://dx.doi.org/10.3390/ijerph14050507 |
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