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Global atmospheric concentrations of brominated, chlorinated flame retardants and organophosphate esters Cassandra Rauert, Jasmin K Schuster, Anita Eng, and Tom Harner Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b06239 • Publication Date (Web): 06 Feb 2018 Downloaded from http://pubs.acs.org on February 8, 2018
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Environmental Science & Technology
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Global atmospheric concentrations of brominated, chlorinated flame retardants and organophosphate esters
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Cassandra Rauert1, Jasmin K. Schuster1, Anita Eng1, Tom Harner1*
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Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, ON, Canada
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*corresponding author:
[email protected] 1
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Table of Contents Art:
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Abstract
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Polyurethane foam (PUF) disk passive air samples, deployed during 2014 in the Global Atmospheric Passive Sampling (GAPS) Network, were analysed for a range of flame retardants (FRs) including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), brominated and chlorinated novel FRs and organophosphate esters (OPEs). Mean concentrations of PBDEs and novel FRs at the 48 sites monitored ranged from 0.097 to 93 pg/m3 for Σ14PBDEs and from below detection limits to 126 pg/m3 for Σ15novel FRs. For PBDEs, the detected concentrations were similar to those previously reported from samples collected in 2005 at GAPS sites, suggesting global background atmospheric concentrations of PBDEs have not declined since regulatory measures were implemented. OPEs were detected at every GAPS site, with Σ18OPEs ranging from 69 to 7770 pg/m3. OPE concentrations were at least an order of magnitude higher than the PBDEs. This study presents the first data on global distributions of OPEs in the atmosphere, obtained from a single passive sampling monitoring network. Challenges that can arise in passive air sampling campaigns are also highlighted and addressed with suggested recommendations for future campaigns.
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Introduction
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Polybrominated diphenyl ethers (PBDEs) have been used historically as flame retardants1 (FRs) and due to concerns over their persistency, bioaccumulative properties and toxicity coupled with high levels of human exposure2, they have been listed as persistent organic pollutants (POPs) by the United Nations Environmental Programme’s (UNEP) Stockholm Convention. The pentaBDE and octaBDE formulations were listed in Annex A in 20093, and after extensive review the decaBDE formulation was also listed in Annex A in April of 2017.3 With the listing of these chemicals and resultant reduction of use, the production and use of alternative flame retardants has increased.4,5 These alternatives include organophosphate esters (OPEs) and a range of other brominated and chlorinated novel flame retardants (which are referred to as “novel FRs” in the following text).
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Applications of the novel FRs include their use as flame retardants in insulation covering wires and cables, in carpets, adhesives, furniture, televisions and computers.5 Although limited information on production volumes is available, it has been reported that in 2006 China produced 2000 and 12,000 tons of dechlorane plus (DP) and decabromodiphenyl ethane (DBDPE), respectively, and 600 tons of hexabromobenzene (HBB) annually.6 DP is classed as a high production volume chemical in the USA, meaning at least 450 tons/year are produced or imported.7 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) had a global production/usage of 16,710 tons in 2001. 6 Production of bis(2-ethyl-1-hexyl) tetrabromophthalate (BEH-TEBP) has increased from 450 to 4500 tons/year from 1990 to 2006 in the USA, however, there is no production information available on 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), which is commonly used with BEH-TEBP in the Firemaster® 550 product along with its single applications as a FR.6 Global market demand of hexabromocyclododecane (HBCD) was 22,000 tons/year in 2003, marking it as a high production volume chemical.6 The OPEs have more widespread uses than the novel FRs including not only as flame retardants, but also as plasticizers, in hydraulic fluids and anti2 ACS Paragon Plus Environment
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foaming agents. The halogenated OPEs are more commonly used as FRs while the non-halogenated OPEs are seeing an increasing use as plasticizers.8 Production of the chlorinated OPEs has increased in the USA from 14,000 tons/year in the mid-80s to 38,000 tons/year in 20129, and total consumption of OPEs in Europe in 2006 was 93,000 tons.10
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As a result of the increasing production/use of these alternative flame retardants, they are consistently detected in the environment6,8, and many of them show properties of persistency and toxicity5,9 leading to concerns over environmental levels. In the case of HBCD, this has led to its addition to the Stockholm Convention in 2013 for elimination with restricted uses.3 These alternative FRs are also detected regularly in geographically remote regions (such as polar regions) indicating a potential to undergo long range atmospheric transport8,11-13 and as such, more extensive global monitoring data is needed on these chemicals of concern.
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One global monitoring program providing atmospheric data on legacy POPs and on new and emerging chemicals of concern is the Global Atmospheric Passive Sampling (GAPS) Network. The GAPS Network has been operational since 2005 and is one of the strategic partners for air monitoring contributing to the Global Monitoring Plan (GMP) of the Stockholm Convention. The GMP was implemented in 2007 as a means to: evaluate the effectiveness of the Convention in reducing environmental levels of POPs, to streamline existing monitoring efforts and to further develop global monitoring networks.14 The regional monitoring in the GMP is divided into the five United Nations regions: Africa, Asia and Pacific, Central and Eastern Europe, Group of Latin American and Caribbean (GRULAC) and Western Europe and Others Group (WEOG). Global monitoring initiatives, such as the GAPS Network, aim to provide data for all regions where possible. Along with providing data for the GMP, the GAPS program also contributes to domestic initiatives, in particular the Government of Canada’s Chemicals Management Plan (CMP).
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Atmospheric concentrations of a range of FRs have been reported in previous GAPS sampling campaigns with Pozo et al.15 reporting PBDEs in atmospheric samples collected in 2005, the first year of the GAPS program. Recently Lee et al. 16 reported the first global-scale distributions of novel FRs in air collected in 2005 and 2006 under the GAPS Network. OPEs have been reported from the GAPS Network in a special study of air samples collected in 2014 in the GRULAC region.17 As yet global atmospheric levels and trends from a single monitoring program have not been reported for OPEs.
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The objectives of this study were to analyse passive air samples from the GAPS Network almost a decade after the conception of the GAPS program, comparing levels of legacy and “new” FRs and where possible, comparing atmospheric concentrations over the last decade or defining global baseline levels of the newer chemicals of concern. In particular, the focus is on 15 PBDE congeners, a range of 14 novel FRs and 18 OPEs. This is the first time a comprehensive list of flame retardants encompassing brominated, chlorinated and phosphorus compounds have been reported from a single global atmospheric monitoring network.
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Materials and Methods
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Polyurethane foam passive air samplers (PUF-PAS) were deployed at 48 global sites from January 2014 to December 2014 for three month sampling periods providing 4 sampling quarters throughout the year, 3 ACS Paragon Plus Environment
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referred to as Q1, Q2, Q3 and Q4. Site details are listed in Table S1 and deployment information is listed in Table S2 and S3 in the Supporting Information (SI). Prior to deployment, PUF-PAS were pre-cleaned and shipped as previously reported in Schuster et al. 18 and extraction procedures were conducted following previously reported methods.17 The PUF-PAS captures a representative value of both gas and particle phase chemicals19 and the air concentrations were derived from an air sampling volume determined using the GAPS Template.20 The OPEs and novel FRs (including HBCD) were assumed to stay in the linear sampling phase during deployment and the effective air volume was calculated as the number of days the PUF-PAS was deployed (~90) multiplied by a sampling rate of 4 m3/day. A previous uptake study of OPEs to PUF disks by Abdollahi et al.21 reported that sampling is predominantly in the linear phase region for the OPEs, for deployments of a few months, and sampling rates are consistent with the default value of 4 m3/day.
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Where a target analyte was not detected, “less than” the method detection limit (
