Environmental Pollution 196 (2015) 284e291
Contents lists available at ScienceDirect
Environmental Pollution journal homepage: www.elsevier.com/locate/envpol
Novel brominated flame retardants and dechlorane plus in Greenland air and biota t b, Henrik Skov a, Christian Sonne b, Katrin Vorkamp a, *, Rossana Bossi a, Frank F. Rige Rune Dietz b a b
Aarhus University, Department of Environmental Science, Arctic Research Centre (ARC), Frederiksborgvej 399, DK-4000 Roskilde, Denmark Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, DK-4000 Roskilde, Denmark
a r t i c l e i n f o
a b s t r a c t
Article history: Received 29 August 2014 Received in revised form 3 October 2014 Accepted 6 October 2014 Available online
Following the ban of polybrominated diphenyl ethers, other halogenated flame retardants (FRs) might be used increasingly. This study has analyzed hexabromocyclododecane (HBCD), 1,2-bis(2,4,6tribromophenoxy)-ethane (BTBPE), 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and dechlorane plus (DP) in Greenland air over the course of a year. Moreover, BTBPE, DPTE, DP, 2-ethylhexyl2,3,4,5-tetrabromobenzoate (TBB), bis(2-ethylhexyl)tetrabromophthalate (TBPH) and decabromodiphenyl ethane (DBDPE) were analyzed in samples of polar bear, ringed seal, black guillemot and glaucous gull from Greenland. HBCD in air appeared low, while mean concentrations of syn- and anti-DP were 2.3 and 5.2 pg/m3, respectively. BTBPE and DPTE were undetectable in air. Detection frequencies in biota were 75% (mean 91%) for the method including the column clean-up (Supporting information). As some samples had lower recoveries in the GPC clean-up (>22%; mean 87%), TBPH was quantified by isotope dilution with 13C-TBPH. Spiked and non-spiked duplicate samples of
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K. Vorkamp et al. / Environmental Pollution 196 (2015) 284e291
the laboratory reference material (sand eel oil) included in the same sample batch showed reasonable agreement with target values (not consistently for DBDPE) as described in the Supporting information. The lipid content of the biota samples was determined according to Smedes (1999). This method is similar to that of Bligh and Dyer (1959), but avoids chlorinated solvents by using isopropanol and cyclohexane. PCBs, PBDEs and HBCD were analyzed in some of the same samples using the methods previously described by Vorkamp et al. (2004a; b; 2012). 2.6. Data analysis Estimation of means and standard deviations for compounds with less than 80% of the values < MDL was done by Regression on Order Statistics (ROS) using the library NADA of the statistical R packages (Helsel, 2005; R Core Team, 2013). No estimation of means and standard deviation was done if more than 80% of the values were below MDL. For calculation of SHBCD, concentrations < MDL were set to zero. We did not make assumptions about the underlying data distribution because of N 5; therefore non-parametric ManneWhitney and KruskaleWallis tests were applied to test for differences in compound concentrations. Test p-values below 5% were regarded as significant. 3. Results and discussion 3.1. HBCD in air Particle bound SHBCD ranged between 0.0057 and 0.13 pg/m3. With the exception of concentrations in January and August, the results indicate a winter maximum. In half of the samples, g-HBCD was the main isomer, in the other half, it was a-HBCD (Fig. 1). On average, a- and g-HBCD accounted for 30% and 60% of SHBCD, respectively, each with a range of 0e100%. There seems to be a slight tendency of relatively more a-HBCD in the winter samples, however, the August sample does not match this pattern. The technical HBCD product contains about 80% g-HBCD unless high temperatures changed the isomer ratio (Covaci et al., 2006). Textile products treated with technical HBCD were found to contain similar amounts of a- and g-HBCD which the authors attributed to isomerization processes during manufacture (Kajiwari and Takigami, 2013). Inconsistent information exists in the literature concerning the vapor pressures of the HBCD isomers, including comparable vapor pressures for a- and g-HBCD (Mariussen et al., 2010) and higher vapor pressures for a-than for g-HBCD (Kajiwari and Takigami, 2013). A photolytic conversion of g-to a-HBCD has been shown for HBCD associated with dust (Harrad et al., 2009). The same study also observed a degradative loss of HBCD by elimination of HBr, which was enhanced by sunlight. Both processes could have taken place during the atmospheric transport of HBCD to Greenland. Low atmospheric HBCD concentrations have also been reported for Zeppelin station on Svalbard, i.e. only two values were above MDLs in 2012, a-HBCD ¼ 0.026 pg/m3 in October and gHBCD ¼ 0.235 pg/m3 in December (Aas et al., 2013). Higher concentrations in winter are consistent with our observations, but more data will be needed for consolidation. Aas et al. (2013) could relate the highest HBCD concentrations to trajectories from Europe, including western Russia. At the Pallas station in Northern Finland, a concentration of 2e3 pg/m3 was measured in 2000e2001 (Remberger et al., 2004). This might suggest a trend of decreasing HBCD concentrations with latitude, which would be supported by higher HBCD concentrations in ringed seals from Svalbard than from Greenland (Sørmo et al., 2006; Vorkamp et al., 2011).
Fig. 1. Concentrations (pg/m3) of HBCD (A) and syn- and anti-dechlorane plus (B) in Greenland air, measured at Station Nord in 2012. Values below the detection limit are shown as zero.
However, due to the high variability of air concentrations, the comparability between older and more recent data is limited. The absence of PUF samples, which had been included in other studies, could have biased our results. However, HBCD has been shown to occur almost entirely in the particulate phase of outdoor air (Hoh and Hites, 2005; Yu et al., 2008).
3.2. NBFRs and dechlorane plus (DP) in air BTBPE and DPTE were below MDLs in all samples (Table 1). The BTBPE concentrations previously reported from the Arctic were below the MDLs of our study. Studies from the Bering/Chukchi Sea the East Greenland Sea and Svalbard reported maximum concen€ ller et al., 2011a; b; Salamova et al., 2014), trations of 0.17 pg/m3 (Mo while measurements at Alert (Canada) showed somewhat higher concentrations of up to 1.9 pg/m3 (Xiao et al., 2012). Unlike BTBPE, DPTE was among the dominating NBFRs in the air of the Bering/ €ller Chukchi Sea, with a maximum concentration of 1.7 pg/m3 (Mo et al., 2011a). DP was above MDLs in approximately half of the samples (Table 1; Fig. 1). The concentrations vary throughout the year, with the highest occurrence in June and October. The maxima were not clearly encompassed by increasing and decreasing concentrations, as could be expected, which might be related to the noncontinuous measurements in combination with varying transport episodes and a concentration dependency on local weather conditions (Kallenborn et al., 2007). They did not co-occur with HBCD
K. Vorkamp et al. / Environmental Pollution 196 (2015) 284e291 Table 1 Detection frequencies (%), mean concentrations and ranges (pg/m3) for HBCD, NBFRs and dechlorane plus (DP) analyzed in monthly air samples from Station Nord. For compounds with less than 80% of the concentrations < MDL, means were estimated by Regression on Order Statistics (ROS).
a-HBCD b-HBCDa g-HBCDa a
BTBPE DPTE Syn-DP Anti-DP a b
N
Detection frequency (%)
Mean (pg/m3)
Range (pg/m3)
12 12 12 13 13 13b 13b
67 50 90 0 0 46 46
0.015 0.0056 0.014 e e 2.32 5.24
Contents lists available at ScienceDirect
Environmental Pollution journal homepage: www.elsevier.com/locate/envpol
Novel brominated flame retardants and dechlorane plus in Greenland air and biota t b, Henrik Skov a, Christian Sonne b, Katrin Vorkamp a, *, Rossana Bossi a, Frank F. Rige Rune Dietz b a b
Aarhus University, Department of Environmental Science, Arctic Research Centre (ARC), Frederiksborgvej 399, DK-4000 Roskilde, Denmark Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, DK-4000 Roskilde, Denmark
a r t i c l e i n f o
a b s t r a c t
Article history: Received 29 August 2014 Received in revised form 3 October 2014 Accepted 6 October 2014 Available online
Following the ban of polybrominated diphenyl ethers, other halogenated flame retardants (FRs) might be used increasingly. This study has analyzed hexabromocyclododecane (HBCD), 1,2-bis(2,4,6tribromophenoxy)-ethane (BTBPE), 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and dechlorane plus (DP) in Greenland air over the course of a year. Moreover, BTBPE, DPTE, DP, 2-ethylhexyl2,3,4,5-tetrabromobenzoate (TBB), bis(2-ethylhexyl)tetrabromophthalate (TBPH) and decabromodiphenyl ethane (DBDPE) were analyzed in samples of polar bear, ringed seal, black guillemot and glaucous gull from Greenland. HBCD in air appeared low, while mean concentrations of syn- and anti-DP were 2.3 and 5.2 pg/m3, respectively. BTBPE and DPTE were undetectable in air. Detection frequencies in biota were 75% (mean 91%) for the method including the column clean-up (Supporting information). As some samples had lower recoveries in the GPC clean-up (>22%; mean 87%), TBPH was quantified by isotope dilution with 13C-TBPH. Spiked and non-spiked duplicate samples of
286
K. Vorkamp et al. / Environmental Pollution 196 (2015) 284e291
the laboratory reference material (sand eel oil) included in the same sample batch showed reasonable agreement with target values (not consistently for DBDPE) as described in the Supporting information. The lipid content of the biota samples was determined according to Smedes (1999). This method is similar to that of Bligh and Dyer (1959), but avoids chlorinated solvents by using isopropanol and cyclohexane. PCBs, PBDEs and HBCD were analyzed in some of the same samples using the methods previously described by Vorkamp et al. (2004a; b; 2012). 2.6. Data analysis Estimation of means and standard deviations for compounds with less than 80% of the values < MDL was done by Regression on Order Statistics (ROS) using the library NADA of the statistical R packages (Helsel, 2005; R Core Team, 2013). No estimation of means and standard deviation was done if more than 80% of the values were below MDL. For calculation of SHBCD, concentrations < MDL were set to zero. We did not make assumptions about the underlying data distribution because of N 5; therefore non-parametric ManneWhitney and KruskaleWallis tests were applied to test for differences in compound concentrations. Test p-values below 5% were regarded as significant. 3. Results and discussion 3.1. HBCD in air Particle bound SHBCD ranged between 0.0057 and 0.13 pg/m3. With the exception of concentrations in January and August, the results indicate a winter maximum. In half of the samples, g-HBCD was the main isomer, in the other half, it was a-HBCD (Fig. 1). On average, a- and g-HBCD accounted for 30% and 60% of SHBCD, respectively, each with a range of 0e100%. There seems to be a slight tendency of relatively more a-HBCD in the winter samples, however, the August sample does not match this pattern. The technical HBCD product contains about 80% g-HBCD unless high temperatures changed the isomer ratio (Covaci et al., 2006). Textile products treated with technical HBCD were found to contain similar amounts of a- and g-HBCD which the authors attributed to isomerization processes during manufacture (Kajiwari and Takigami, 2013). Inconsistent information exists in the literature concerning the vapor pressures of the HBCD isomers, including comparable vapor pressures for a- and g-HBCD (Mariussen et al., 2010) and higher vapor pressures for a-than for g-HBCD (Kajiwari and Takigami, 2013). A photolytic conversion of g-to a-HBCD has been shown for HBCD associated with dust (Harrad et al., 2009). The same study also observed a degradative loss of HBCD by elimination of HBr, which was enhanced by sunlight. Both processes could have taken place during the atmospheric transport of HBCD to Greenland. Low atmospheric HBCD concentrations have also been reported for Zeppelin station on Svalbard, i.e. only two values were above MDLs in 2012, a-HBCD ¼ 0.026 pg/m3 in October and gHBCD ¼ 0.235 pg/m3 in December (Aas et al., 2013). Higher concentrations in winter are consistent with our observations, but more data will be needed for consolidation. Aas et al. (2013) could relate the highest HBCD concentrations to trajectories from Europe, including western Russia. At the Pallas station in Northern Finland, a concentration of 2e3 pg/m3 was measured in 2000e2001 (Remberger et al., 2004). This might suggest a trend of decreasing HBCD concentrations with latitude, which would be supported by higher HBCD concentrations in ringed seals from Svalbard than from Greenland (Sørmo et al., 2006; Vorkamp et al., 2011).
Fig. 1. Concentrations (pg/m3) of HBCD (A) and syn- and anti-dechlorane plus (B) in Greenland air, measured at Station Nord in 2012. Values below the detection limit are shown as zero.
However, due to the high variability of air concentrations, the comparability between older and more recent data is limited. The absence of PUF samples, which had been included in other studies, could have biased our results. However, HBCD has been shown to occur almost entirely in the particulate phase of outdoor air (Hoh and Hites, 2005; Yu et al., 2008).
3.2. NBFRs and dechlorane plus (DP) in air BTBPE and DPTE were below MDLs in all samples (Table 1). The BTBPE concentrations previously reported from the Arctic were below the MDLs of our study. Studies from the Bering/Chukchi Sea the East Greenland Sea and Svalbard reported maximum concen€ ller et al., 2011a; b; Salamova et al., 2014), trations of 0.17 pg/m3 (Mo while measurements at Alert (Canada) showed somewhat higher concentrations of up to 1.9 pg/m3 (Xiao et al., 2012). Unlike BTBPE, DPTE was among the dominating NBFRs in the air of the Bering/ €ller Chukchi Sea, with a maximum concentration of 1.7 pg/m3 (Mo et al., 2011a). DP was above MDLs in approximately half of the samples (Table 1; Fig. 1). The concentrations vary throughout the year, with the highest occurrence in June and October. The maxima were not clearly encompassed by increasing and decreasing concentrations, as could be expected, which might be related to the noncontinuous measurements in combination with varying transport episodes and a concentration dependency on local weather conditions (Kallenborn et al., 2007). They did not co-occur with HBCD
K. Vorkamp et al. / Environmental Pollution 196 (2015) 284e291 Table 1 Detection frequencies (%), mean concentrations and ranges (pg/m3) for HBCD, NBFRs and dechlorane plus (DP) analyzed in monthly air samples from Station Nord. For compounds with less than 80% of the concentrations < MDL, means were estimated by Regression on Order Statistics (ROS).
a-HBCD b-HBCDa g-HBCDa a
BTBPE DPTE Syn-DP Anti-DP a b
N
Detection frequency (%)
Mean (pg/m3)
Range (pg/m3)
12 12 12 13 13 13b 13b
67 50 90 0 0 46 46
0.015 0.0056 0.014 e e 2.32 5.24
