Article pubs.acs.org/est
Brominated Flame Retardants and Dechlorane Plus in the Marine Atmosphere from Southeast Asia toward Antarctica Axel Möller,*,†,‡ Zhiyong Xie,† Minghong Cai,§ Renate Sturm,† and Ralf Ebinghaus† †
Helmholtz−Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max−Planck−Strasse 1, 21502 Geesthacht, Germany ‡ Leuphana University Lüneburg, Institute for Ecology and Environmental Chemistry, Scharnhorststrasse 1, 21335 Lüneburg, Germany § SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China S Supporting Information *
ABSTRACT: The occurrence, distribution, and temperature dependence in the marine atmosphere of several alternative brominated flame retardants (BFRs), Dechlorane Plus (DP) and polybrominated diphenyl ethers (PBDEs) were investigated during a sampling cruise from the East Indian Archipelago toward the Indian Ocean and further to the Southern Ocean. Elevated concentrations were observed over the East Indian Archipelago, especially of the non-PBDE BFR hexabromobenzene (HBB) with concentrations up to 26 pg m−3 which were found to be related to continental air masses from the East Indian Archipelago. Other alternative BFRs pentabromotoulene (PBT), pentabromobenzene (PBBz), and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE)were elevated, too, with concentrations up to 2.8, 4.3, and 2.3 pg m−3, respectively. DP was detected from 0.26 to 11 pg m−3 and bis-(2-ethylhexyl)tetrabromophthalate (TBPH) ranged from not detected (nd) to 2.8 pg m−3, respectively. PBDEs ranged from nd to 6.6 pg m−3 (Σ10PBDEs) with the highest individual concentrations for BDE-209. The approach of Clausius−Clapeyron (CC) plots indicates that HBB is dominated by long-range atmospheric transport at lower temperatures over the Indian and Southern Ocean, while volatilization processes and additional atmospheric emissions dominate at higher temperatures. In contrast, BDE-28 and -47 are dominated by long-range transport without fresh emissions over the entire cruise transect and temperature range, indicating limited fresh emissions of the meanwhile classic PBDEs.
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INTRODUCTION Halogenated flame retardants (HFRs) are applied to reduce the flammability of many consumer products such as electrical and electronic products (E&E), textiles, and furnishings in order to protect humans from outbreak and spread of fires. They have been industrial chemicals of growing worldwide environmental and political concern in the 1990s and 2000s, and are still an emerging class of chemicals. Polybrominated diphenyl ethers (PBDEs) were the most produced and used brominated flame retardants (BFRs) in the 1990s and early 2000s. They are known to be harmful for the environment and humans because of their toxicity, bioaccumulation potential, and persistence in the environment, as well as their potential to be atmospherically transported from source regions over very long distances toward remote regions.1 Meanwhile, the production and use of two traditional industrial PBDE mixturesPenta- and OctaBDEhas been restricted worldwide and they were included into the Stockholm Convention on Persistent Organic Pollutants (POPs) in 2009 (www.pops.int). The third technical PBDE mixtureDecaBDEis still being produced, even though its application is partly restricted (e.g., in E&E equipment in the European Union (EU)2) and production © 2012 American Chemical Society
phase-outs have been announced (e.g., for 2012 in the United States3). PBDEs have been detected worldwide in various environmental compartments4,5 including remote regions such as the Arctic6 and Antarctic.7 In recent years, an increasing number of studies focused on the Asian environment due to (a) the growing (BFR) industry in Asian countries, in particular in China, and (b) the treatment of electronic waste (e-waste) which is being shipped mainly from Europe and Northern America to Asia, again predominantly to China, and recycled rather primitively (e.g., burning in open fires).8−11 In addition to PBDEs, alternative aromatic BFRs such as 1,2-bis(2,4,6tribromophenoxy)-ethane (BTBPE), and bis-(2-ethylhexyl)tetrabromophthalate (TBPH) have received emerging concern due to their application as PBDE-replacements. Even more alarming, some alternative BFRs have been used similar to PBDEs for several decades (e.g., hexabromobenzene (HBB), Received: Revised: Accepted: Published: 3141
January 16, 2012 February 27, 2012 February 29, 2012 February 29, 2012 dx.doi.org/10.1021/es300138q | Environ. Sci. Technol. 2012, 46, 3141−3148
Environmental Science & Technology
Article
pentabromotoluene (PBT)12) but have been omitted from most environmental investigations on BFRs during that time. Besides, another highly chlorinated flame retardant with annual production volumes of several thousand tonsDechlorane Plus (DP)has been frequently investigated since its first report in the environment in 2006,13 but its production and usage had already started already back in the 1970s.13 Several alternative BFRs and DP have been detected on different continents as summarized in recent reviews.6,14,15 Nevertheless, knowledge on their possible adverse effects, bioaccumulation potential and occurrence, distribution, and transport in the environment is still very limited. Because PBDEs and several alternative BFRs can be classified as semivolatile chemicals they can be transported in the gas phase over long ranges from source regions toward the Polar Regions, or, as shown for the extremely hydrophobic nonvolatile HFRs such as BDE-209 and DP, be transported attached to airborne particles over similar ranges.16,17 Thereby, they travel over the global oceans and can interact with the oceans surface including deposition processes. These are important sources for the open oceans, besides riverine inputs which mainly influence coastal environments. Once deposited into the ocean, they become bioavailable for marine organisms and are subject to further transport via ocean currents. In addition, they can revolatilize into the atmosphere or deposit in sediments. Besides PBDEs, several non-PBDE BFRs, namely HBB, PBT, 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), and DP, have been recently detected during sampling cruises in the European Arctic, the Northern and Southern Atlantic Ocean toward Antarctica, and the Northern Pacific Ocean toward the high Arctic in similar or even higher concentrations.17−20 Obviously, they share the property of long-range atmospheric transport (LRAT) potential with PBDEs but this still needs to be investigated for further oceanic regions. In the present study, we investigated the occurrence and spatial distribution of PBDEs and several alternative BFRs as well as dechloranes in the atmosphere during a sampling cruise through the East Indian Archipelago (EIA) toward the west coast of Australia, and further to the Southern Ocean toward Antarctica, with respect to possible source regions and temperature dependence, especially of alternative BFRs to further improve the understanding of the global atmospheric transport of (alternative) BFRs and DP.
extraction. Sampling parameters such as latitude, longitude, and air temperature are included in Table S1 in the Supporting Information (SI). Extraction, Cleanup, and Analysis. Extraction, cleanup, and analysis of the samples followed the method described in Möller et al.17 Air columns and filters were extracted separately while only half of the filter was used for extraction. Briefly, the samples were spiked with 200 pg of each 13C−HBB, 13C−BDE77, 13C−BDE-138 (Wellington Laboratories), and 13C−synDP (Cambridge Isotope Laboratories) and with 2000 pg 13C− BDE-209 (Wellington Laboratories) as surrogates, extracted by dichloromethane in a Soxhlet apparatus and further cleaned on a silica column (2.5 g, 10% water deactivated) topped on anhydrous granulated sodium sulfate. After volume reduction to 30 μL, 500 pg of CB-207 (Dr. Ehrenstorfer GmbH) was added as a recovery standard prior to injection. Analysis was done by a GC/MS-system (Agilent 6890 GC/5975 MSD) in electron capture negative chemical ionization mode (ECNCI). The analytes were separated on a HP-5MS column (30 m × 0.25 mm i.d. × 0.25 μm film thickness, J&W Scientific) except BDE209 which was separated using a DB5-MS column (15 m × 0.25 mm i.d. × 0.10 μm film thickness, J&W Scientific). Samples were analyzed for 10 PBDE congeners (-28, -47, -66, -85, -99, -100, -153, -154, -183, -209), 8 alternative BFRs (pentabromobenzene (PBBz), HBB, PBT, pentabromoethylbenzene (PBEB), DPTE, BTBPE, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EHTBB) and TBPH (all obtained from Wellington Laboratories)), synDP and antiDP and the 1- and 2-fold dechlorinated DP species (aCl11DP [−1Cl + 1H], aCl10DP [−2Cl + 2H]; Wellington Laboratories), and Dechlorane 602, 603, and 604 (Toronto Research Chemicals). QA/QC. As described elsewhere, good care was taken to avoid sample contamination before sampling, during sampling, and during extraction and further treatment.17,19 By sampling in the front of the most upper deck and sampling during good wind conditions only, which means no sampling during backwinds which might transport exhaust gas to the sampler, the risk of possible contamination by the ship itself was limited as much as possible. In addition, sampling was stopped at wind speeds
