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Chemical mass transfer of an organophosphate flame retardant between product source and dust in direct contact
Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Organophosphate flame retardants (OPFRs) are a group of semi-volatile organic compounds (SVOCs) which are ubiquitous and among the most abundant contaminants indoors. Despite the fact that their indoor presence has been shown to contribute significantly to human exposure and has been associated with potential health risks there is limited understanding as to how they are released from indoors sources. This study uses an emission micro-chamber to explore one of the currently understudied chemical migration pathways; direct transfer between a source material and settled dust in contact with the source. A tris(2-chloroisopropyl) phosphate (TCIPP)-treated insulation board is used as the source material. Rapid and substantial transfer was observed after only 8 h of source-dust contact, resulting in 80 times higher concentrations in dust compared to pre-experiment levels. Further time points at 24 h and 7 d showed similarly high average dust levels and the TCIPP in the dust and air in the chamber was calculated to be close to thermodynamic equilibrium during the experiment. It was concluded that TCIPP was effectively transferred from the insulation board to the dust on its surface and the surrounding air via gas-phase diffusion. As the TCIPP in the air and dust in the chamber appear close to equilibrium, there is no evidence from this experiment that TCIPP levels in dust in direct contact with product surfaces indoors would be enhanced compared to dust levels in the rest of the room. In a real room however where such well-mixed conditions as in the micro-chamber do not generally apply there might be a gradient of concentrations of TCIPP in air above the surface of a product. This could result in higher concentrations in dust sitting on the product than dust in the rest of the room.

National Category
Environmental Sciences
Research subject
Applied Environmental Science
Identifiers
URN: urn:nbn:se:su:diva-127261OAI: oai:DiVA.org:su-127261DiVA: diva2:907786
Available from: 2016-02-29 Created: 2016-02-29 Last updated: 2016-03-02Bibliographically approved
In thesis
1. Indoor emissions and fate of flame retardants: A modelling approach
Open this publication in new window or tab >>Indoor emissions and fate of flame retardants: A modelling approach
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A significant number of consumer goods and building materials act as emission sources of flame retardants (FRs) in the indoor environment. As a result, FRs have become ubiquitous indoors raising concerns about human exposure and possible health implications. Once released indoors, FRs can escape to the outdoors where they can persist, be transported over long distances and present a threat to the environment. Despite the increasing number of studies reporting the occurrence of FRs in the indoor environment, the understanding of i) how and to what extent these chemicals are released from indoor sources, and ii) their subsequent fate indoors remains limited. The overarching objective of this thesis was to improve this understanding by assessing the indoor emissions and fate of FRs using a combination of multimedia modelling strategies and experimental/empirical approaches. Paper I identifies a number of knowledge gaps and limitations regarding indoor emissions and fate of FRs and the available modelling approaches. These include a limited understanding of the key emission mechanisms for low volatility FRs, uncertainties regarding indoor air/surface partitioning, poor characterization of dust and film dynamics and a significant lack of knowledge regarding indoor reaction/degradation processes. In Paper II we highlighted the serious scarcity in physicochemical property data for the alternative FRs and demonstrated the applicability of a simple QSPR technique for selecting reliable property estimates for chemical assessments. A modelling fate assessment indicated a strong partitioning to indoor surfaces and dust for most of the alternative FRs. Indications for POP (persistent organic pollutant)-like persistence and LRT (long-range transport) and bioaccumulative potential in the outdoor environment were also identified for many alternative FRs. Using an inverse modelling approach in Paper III we estimated 2 to 3 orders of magnitude higher emissions of organophosphate FRs (0.52 and 0.32 ng.h-1) than brominated FRs (0.083 μg.h-1 and 0.41 μg.h-1) in Norwegian households. An emission-to-dust signal was also identified for organophosphate FRs suggesting that direct migration to dust may be a key fate process indoors. No evidence of a direct source-to-dust transfer mechanism was seen in Paper IV where the chemical transfer between a product treated with an organophosphate FR and dust in direct contact was experimentally investigated. It was concluded though that direct contact between an FR source and dust can result in contamination hotspots indoors.

Place, publisher, year, edition, pages
Stockholm: Department of Environmental Science and Analytical Chemistry, Stockholm University, 2016
Keyword
flame retardants, BFRs, OPFRs, indoor environment, emissions, fate, modelling
National Category
Environmental Sciences
Research subject
Applied Environmental Science
Identifiers
urn:nbn:se:su:diva-127258 (URN)978-91-7649-341-0 (ISBN)
Public defence
2016-04-08, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 12, Stockholm, 13:00 (English)
Opponent
Supervisors
Funder
EU, FP7, Seventh Framework Programme, 264600
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Available from: 2016-03-16 Created: 2016-02-29 Last updated: 2016-04-05Bibliographically approved

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Liagkouridis, IoannisGiovanoulis, GeorgiosCousins, Ian
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