Concentrations of polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs) have been rapidly increasing in fish, birds, sediments, indoor environments, and humans, but emission sources and exposure pathways of these pollutants remain poorly understood. The many BFR-containing materials in buildings constitute a large reservoir of these compounds, and in-use releases from this reservoir may be a significant environmental source. To estimate in-use releases from building materials and contents in residences, we monitored 12 houses and garages in two seasons and combined measurements of BFRs in air and settled dust, air exchange rates, and other information in an approach that utilized the building as a "natural" test chamber. Results were scaled to provide a first estimate of aggregate emission rates from U.S. houses. PBDE releases total about 4 microg h(-1) per house or 20 ng m(-2) h(-1), and U.S. houses and garages collectively release about 4100 kg y(-1). Most of these releases are settled floor dust, but about 20% are released directly to the ambient environment via airborne vapor and particulate matter. These screening-level estimates are subject to considerable uncertainty, but they have an advantage in that they reflect real-world conditions based on mass balance calculations.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to develop and validate a new analytical protocol for simultaneous determination of 62 semi-volatile organic compounds in both phases of indoor air. Studied compounds belong to several families: polybrominated diphenyl ethers, polychlorinated biphenyls, hexachlorobenzene, pentachlorobenzene, phthalates, polyaromatic hydrocarbons, parabens, tetrabromobisphenol A, bisphenol A, hexabromocyclododecane, triclosan, alkylphenols, alkylphenol ethoxylates, synthetic musks (galaxolide and tonalide) and pesticides (lindane and cypermethrin). A medium volume sampling system was used to collect simultaneously these endocrine-disrupting compounds (EDCs) from the gaseous and particulate phases. An accelerated solvent extraction method was optimized to obtain all EDCs in a single extract by atmospheric phase. Their extraction from the sorbents and their analysis by liquid and gas chromatography-mass spectrometry (LC/MS/MS, GC/MS and GC/MS/MS) was validated using spiked sorbents (recovery study and analytical uncertainty analysis by fully nested design). The developed protocol achieved low limits of quantification (<0.5 ng m-3) and low uncertainty values (<5 ng m-3) for all compounds. Once validated, the method was applied to indoor air samples from four locations (a house, an apartment, a day nursery and an office) and compared to literature to confirm its efficiency. All target EDCs were quantified in the samples and were primarily present in the gaseous phase. The major contaminants found in indoor air were, in descending order, phthalates, synthetic musks, alkylphenols and parabens.
"PBDEs were calculated in this study which were comparable to PBDE emission factors of 2 × 10 −7 to 7.1 × 10 −7 yr −1 (g · yr −1 per g in TV rear cover) estimated by Sakai et al. (2006) for migration to dust inside TV cabinets. Appreciable attempts have been made to estimate (back-calculate) PBDE emissions from measured indoor concentrations either using models based on simple equations (Batterman et al., 2009) or by applying more sophisticated mass-balance modelling methods (Zhang et al., 2009, 2011). Even though model predictions were in some cases comparable to experimentally derived values, associated uncertainties with model formulations indicate the need for further combined chamber-modelling studies. "
[Show abstract][Hide abstract] ABSTRACT: This review explores the existing understanding and the available approaches to estimating the emissions and fate of semi-volatile organic compounds (SVOCs) and in particular focuses on the brominated flame retardants (BFRs). Volatilisation, an important emission mechanism for the more volatile compounds can be well described using current emission models. More research is needed, however, to better characterise alternative release mechanisms such as direct material-particle partitioning and material abrasion. These two particle-mediated emissions are likely to result in an increased chemical release from the source than can be accounted for by volatilisation, especially for low volatile compounds, and emission models need to be updated in order to account for these. Air-surface partitioning is an important fate process for SVOCs such as BFRs however it is still not well characterised indoors. In addition, the assumption of an instantaneous air-particle equilibrium adopted by current indoor fate models might not be valid for high-molecular weight, strongly sorbing compounds. A better description of indoor particle dynamics is required to assess the effect of particle-associated transport as this will control the fate of low volatile BFRs. We suggest further research steps that will improve modelling precision and increase our understanding of the factors that govern the indoor fate of a wide range of SVOCs. It is also considered that the appropriateness of the selected model for a given study relies on the individual characteristics of the study environment and scope of the study.
Science of The Total Environment 02/2014; 491. DOI:10.1016/j.scitotenv.2014.02.005 · 4.10 Impact Factor
"Several studies have involved the investigation of temporal variation of PBDE occurrence in indoor dust (Allen et al., 2008; Batterman et al., 2009; Harrad et al., 2008a; Vorkamp et al., 2011; Yu et al., 2012), of which only one study was specifically devoted to this topic (Muenhor and Harrad, 2012). Yet, these investigations were subjected to considerable uncertainty, because most of their conclusions were based on limited and discontinuous sampling sizes. "
[Show abstract][Hide abstract] ABSTRACT: This study documents the temporal variability in concentrations of flame retardants (FRs) in floor dust from three offices in Beijing, China. Dust from Office A (OAD) was collected weekly from March to August, 2012, and sampling of dust from Office B and C (OBD and OCD) was conducted fortnightly (each two weeks) from March to December 2012. With intensive and continuous sampling, we report for the first time on clear and coherent temporal trends of polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs) and phosphorus flame retardants (PFRs) in indoor dust. The observed mean concentrations of ∑9PBDEs, ∑4NBFRs and ∑9PFRs, were 554, 11,100 and 128,000ngg(-1) in OAD; 7560, 5000 and 17,300ngg(-1) in OBD; and 4750, 3550 and 17,200ngg(-1) in OCD, respectively. With exception of PBDEs, concentrations of FRs were elevated in OAD than in OBD and OCD. Two to ten-fold variations were observed between the minimum and maximum concentrations of FRs in the same office, indicating that the sampling moment exerts a substantial influence on the level of FR contamination. Different seasonality was distinctively found between BFRs and PFRs. Except for a few occasional abnormal values, BFR levels in office dust were generally constant among different seasons. The abundance rank order for PFRs was: winter>autumn>summer, with peak values occurring in late winter and early spring. This pattern may be attributable to the fact that PFRs are more sensitive to temperature changes compared to PBDEs and NBFRs owning to their higher volatilities. The absence of significant seasonal variation for BFR concentrations in indoor dust compared to outdoor air and dust concentrations is also discussed.
Environment international 01/2014; 65C:100-106. DOI:10.1016/j.envint.2013.12.011 · 5.56 Impact Factor
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