Identification and quantification of products formed via photolysis of decabromodiphenyl ether |
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Authors: | Anna Christiansson Johan Eriksson Daniel Teclechiel Åke Bergman |
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Institution: | 1. Department of Environmental Chemistry, Stockholm University, Svante Arrhenius v?g 12, 106 91, Stockholm, Sweden
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Abstract: | Background, aim, and scope Decabromodiphenyl ether (DecaBDE) is used as an additive flame retardant in polymers. It has become a ubiquitous environmental
contaminant, particularly abundant in abiotic media, such as sediments, air, and dust, and also present in wildlife and in
humans. The main DecaBDE constituent, perbrominated diphenyl ether (BDE-209), is susceptible to transformations as observed
in experimental work. This work is aimed at identifying and assessing the relative amounts of products formed after UV irradiation
of BDE-209.
Materials and methods BDE-209, dissolved in tetrahydrofuran (THF), methanol, or combinations of methanol/water, was exposed to UV light for 100
or 200 min. Samples were analyzed by gas chromatography/mass spectrometry (electron ionization) for polybrominated diphenyl
ethers (PBDEs), dibenzofurans (PBDFs), methoxylated PBDEs, and phenolic PBDE products.
Results The products formed were hexaBDEs to nonaBDEs, monoBDFs to pentaBDFs, and methoxylated tetraBDFs to pentaBDFs. The products
found in the fraction containing halogenated phenols were assigned to be pentabromophenol, dihydroxytetrabromobenzene, dihydroxydibromodibenzofuran,
dihydroxytribromodibenzofuran, and dihydroxytetrabromodibenzofuran. The PBDEs accounted for approximately 90% of the total
amount of substances in each sample and the PBDFs for about 10%.
Discussion BDE-209 is a source of PBDEs primarily present in OctaBDEs but also to some extent in PentaBDEs, both being commercial products
now banned within the EU and in several states within the USA. It is notable that OH-PBDFs have not been identified or indicated
in any of the photolysis studies performed to date. Formation of OH-PBDFs, however, may occur as pure radical reactions in
the atmosphere.
Conclusions Photolysis of decaBDE yields a wide span of products, from nonaBDEs to hydroxylated bromobenzenes. It is evident that irradiation
of decaBDE in water and methanol yields OH-PBDFs and MeO-PBDFs, respectively. BDE-202 (2,2′,3,3′,5,5′,6,6′-octabromodiphenyl
ether) is identified as a marker of BDE-209 photolysis.
Recommendations and perspectives BDE-209, the main constituent of DecaBDE, is primarily forming debrominated diphenyl ethers with higher persistence which
are more bioaccumulative than the starting material when subjected to UV light. Hence, DecaBDE should be considered as a source
of these PBDE congeners in the environment.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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Keywords: | Chemical reactivity Photolysis Polybrominated dibenzofurans PBDFs Polybrominated diphenyl ethers PBDEs UV degradation |
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