Multiyear Measurements of Flame Retardants and Organochlorine

Jun 22, 2015 - HBB and PBEB were also found in polar bears,(29) indicating the ...... (1983–2010) of contaminant trends in East Greenland polar bear...
0 downloads 0 Views 2MB Size
Subscriber access provided by UNIV OF MISSISSIPPI

Article

Multi-year measurements of flame retardants and organochlorine pesticides in air in Canada’s Western sub-Arctic Yong Yu, Hayley Hung, Nick Alexandrou, Pat Roach, and Ken Nordin Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.5b01996 • Publication Date (Web): 22 Jun 2015 Downloaded from http://pubs.acs.org on June 25, 2015

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Environmental Science & Technology is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 20

Environmental Science & Technology

1

2 3

TOC Art

1 ACS Paragon Plus Environment

Environmental Science & Technology

Page 2 of 20

4

Multi-year measurements of flame retardants and

5

organochlorine pesticides in air in Canada’s Western sub-

6

Arctic

7

Yong Yu 1*, Hayley Hung 1*, Nick Alexandrou 1, Pat Roach 2, Ken Nordin 3

8 9 10

1

Air Quality Processes Research Section, Environment Canada, Toronto, ON, M3H 5T4, Canada

11

2

Aboriginal Affairs and Northern Development Canada, Whitehorse, YT, Y1A 2B5, Canada

12

3

Laberge Environmental Services, Whitehorse, YT, Y1A 2S5, Canada

13 14

Corresponding authors:

15

*Tel: 1-416-739-4770; e-mail: [email protected]

16

*Tel: 1-416-739-5944; fax: 1-416-739-4281; e-mail: [email protected]

17 18

Abstract:

19

Fourteen polybrominated diphenyl ethers (PBDEs), 14 non-BDE flame retardants (FRs) and 25

20

organochlorine pesticides (OCPs) were analyzed in air samples collected at Little Fox Lake (LFL)

21

in Canada’s Yukon Territory from August 2011 to December 2014. LFL is a long term

22

monitoring station operated under the Northern Contaminants Program (NCP) and one of only a

23

few stations that contribute to the assessment of air pollution levels and pathways to the sub-

24

Arctic region. BDE-47 was the most abundant congener among the 14 PBDEs, followed by

25

BDE-99. Non-BDE FRs pentabromotoluene (PBT) and dechlorane plus (DP) were detected in all

26

the

27

hexabromobenzene (HBB), and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB) were also

28

detected in > 75% of all samples. PBDEs have shown decreasing tendency as of 2013, which

29

may reflect the phase out of penta- and octa-BDE mixtures has led to significant decline in the

30

atmosphere. The highest concentrations of OCPs were observed for hexachlorobenzene (HCB),

31

with a median concentration of 61 pg/m3, followed by α-hexachlorocyclohexane (α-HCH) and α-

32

endosulfan. Potential source contribution function (PSCF) highlights Northern Canada, Pacific,

samples.

Dechlorane

602,

2,3-dibromopropyl-2,4,6-tribromophenyl

2 ACS Paragon Plus Environment

ether

(DPTE),

Page 3 of 20

Environmental Science & Technology

33

and East Asia as potential sources in warm seasons; while in cold seasons, the chemicals mainly

34

came from the Pacific Rim.

35 36

Introduction

37

Polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) are two

38

classes of persistent organic pollutants (POPs) which have attracted much public and scientific

39

attention [1]. They were widely used in the world and most of them have been banned or

40

restricted in increasing numbers of countries. Due to their persistence and bioaccumulation

41

potential, they are ubiquitous in various environmental matrices. These trace organic compounds

42

have been detected in wastewater treatment plants (WWTPs), aquatic environment, mammals,

43

and human [2, 3]. However, fewer studies have reported about their occurrence in the

44

atmosphere of remote regions, especially in the western Arctic [4].

45

Long-range atmospheric transport (LRAT) is the most rapid pathway for semi-volatile

46

organic compounds (SVOCs) to travel to remote locations. The occurrence of SVOCs in the

47

Arctic atmosphere has been investigated under the Canadian Northern Contaminants Program

48

(NCP), which is Canada’s National Implementation Plan for the Arctic Monitoring and

49

Assessment Programme (AMAP), to assess LRAT of pollutants. Since 2002, NCP has conducted

50

air monitoring of SVOCs at Little Fox Lake (LFL), in Canada’s Yukon Territory, including

51

measurements of PBDEs, OCPs and polycyclic aromatic hydrocarbons (PAHs) [4].

52

In a previous study, Westgate et al. [5] investigated the occurrence of PBDEs and OCPs

53

from August 2007 to October 2009 at LFL using a super-high-volume air sampler (SHV).

54

However, this type of sampling is expensive and requires high maintenance and is therefore not

55

suitable for long-term monitoring at a remote site like LFL. Xiao et al. [6, 7] developed a flow-

56

through sampler (FTS) for SVOCs in air, which can sample air in the absence of power.

57

Meanwhile, the phase out of penta-, octa-, and deca-BDE has led to the increased use of

58

alternative flame retardants (FRs) in different products. In recent years, various studies explored

59

the presence of non-BDE FRs in air samples [8-10].

60

In this study, we investigated the atmospheric concentrations of OCPs, PBDEs and

61

emerging non-BDE FRs at LFL by FTS. This is the first report of multi-year measurements of

62

non-BDE FRs in air in the western sub-Arctic region. The aim of this study is to examine the

3 ACS Paragon Plus Environment

Environmental Science & Technology

Page 4 of 20

63

monthly variation and time trend of these chemicals and to assess and map the possible source

64

regions of these contaminants at LFL.

65 66

Experimental

67

Chemicals. Fourteen PBDEs (BDE-17, -28, -49, -71, -47, -66, -100, -99, -85, -154, -153, -138,

68

-183, and -190), 14 non-BDE FRs, allyl-2,4,6-tribromophenyl ether (ATE), 2-bromoallyl-2,4,6-

69

tribromophenyl

70

hexabromobenzene (HBB), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy)

71

ethane (BTBPE), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), 2-ethylhexyl

72

2,3,4,5-tetrabromobenzoate

73

dechlorane 602 and 604, syn- and anti- dechlorane plus (DP), and 25 OCPs, α-, β-, γ-, δ-

74

hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), aldrin, dieldrin, endrin, heptachlor,

75

heptachlor epoxide, trans- and cis-chlordane, trans-nonachlor, α- and β-endosulfan, endosulfan

76

sulfate, o,p’-DDE, o,p’-DDD, o,p’-DDT, p,p’-DDE, p,p’-DDD, p,p’-DDT, methoxychlor,

77

oxychlordane, and photomirex, were measured in 42 air samples. Details on these compounds

78

are provided in Table S1.

ether

(BATE),

2,3-dibromopropyl-2,4,6-tribromophenyl

(EH-TBB),

ether

bis(2-ethylhexyl)tetrabromophthalate

(DPTE),

(TBPH),

79 80

Sampling. The sampling site is located in a sub-Arctic environment in the Yukon Territory

81

near LFL (61°21’ N, 135°38’ W, and 1128 m above sea level), about 85 km north of the city of

82

Whitehorse, YT, Canada. The population density of this area is very low, < 0.1 person/km2 [11].

83

Details of the air sampling procedure are described elsewhere [6, 7]. Briefly, the sampling media

84

consist of two 3-inch and one 1-inch polyurethane foam (PUF) plugs, housed in an FTS

85

described previously in Xiao et al. [7]. The FTS turns into the wind with the help of vanes and

86

the air volume collected by the FTS during a 1-month period depends on wind speed and ranged

87

from 1025 m3 to 10,500 m3. Forty-two monthly air samples were collected from August 2011 to

88

December 2014 at LFL with FTS for this study. Details on sampling time and air volume are

89

provided in Table S2. Air monitoring for SVOCs at LFL is continuous and on-going.

90 91

Analytical Procedure. Each PUF in the FTS sample was individually Soxhlet extracted for

92

24 h with 480 mL of acetone and petroleum ether (PE) 1:1 v/v. The extracts were dehydrated 4 ACS Paragon Plus Environment

Page 5 of 20

Environmental Science & Technology

93

with 5 g of sodium sulfate (J.T. Baker, Center Valley, PA), solvent exchanged to 2 mL of

94

isooctane, and 100 ng of mirex was added to each sample for volume correction. All samples

95

were reduced in volume with a Turbovap 500 (Biotage, Charlotte, NC) to 0.5 mL, the volume

96

was brought to 1.0 mL with isooctane, then transferred into a vial.

97

PBDEs and non-BDE FRs were analyzed by gas chromatography- mass spectrometry (GC-

98

MS) using an Agilent 5975 MSD (Mississauga, ON) in negative chemical ionization (NCI) mode

99

with methane as the reagent gas by selected ion monitoring (SIM). Using a DB-5 column (30 m×

100

0.25 mm i.d. × 0.25 µm film thickness, Agilent Technologies, Mississauga, ON), the oven

101

temperature program was as follows: 110 °C for 2 min, increased by 15 °C/min to 160 °C, held

102

for 0 min, increased by 2.5 °C/min to 260 °C, held for 4 min, increased by 2.5°C/min to 285 °C,

103

and then held for 15 min. The source was at 150 °C and the transfer line at 280 °C. The injector

104

was held at 200 °C in pulsed splitless mode.

105

The concentrations of OCPs were analyzed on an Agilent 6890 Gas Chromatograph

106

(Mississauga, ON) with electron capture detector (GC-ECD), coupled with a DB-5 column (60

107

m × 0.25 mm i.d. × 0.25 µm film thickness, J&W Scientific, Folsom, CA), using a temperature

108

program as follows: 80 °C for 1 min, increased by 15 °C/min to 160 °C, and then increased by

109

2.5 °C/min to 265 °C and held for 25 min.

110 111

Quality assurance and quality control. The calibration standards were run at the

112

beginning and at the end of every batch of 8 samples. The average of the two sets of standards

113

were used to quantify the samples analyzed in the batch. Randomly, one 1- or 3-inch PUF was

114

collected as field blank for every sample, while solvent blanks were analyzed for every two

115

samples. Field blanks and solvent blanks were extracted and analyzed in the same manner as

116

PUF samples. Only BDE-47 and -99 were detected in some of the solvent blanks. The other

117

chemicals were not detectable in solvent blanks. BDE-47 and -99 were detected in all the field

118

blanks, and the other compounds were occasionally detectable (Table S3). The method detection

119

limits (MDLs) were calculated from mean of the 12 field blanks + 3 standard deviations. For the

120

chemicals not detected in the field blanks, the instrumental detection limit (IDL), set at S/N

121

ratios = 3, was used for calculating MDLs. MDLs were expressed as IDL divided by an average

122

sampling air volume of 3455 m3. FTS is open to trap both gas and particle phases, and fine

123

particles and gas-phase chemicals may breakthrough. Breakthrough was calculated as the ratios 5 ACS Paragon Plus Environment

Environmental Science & Technology

Page 6 of 20

124

of concentrations on the third PUF (1-inch) to those on all 3 PUFs. Breakthrough was on average

125

5.8% for PBDEs, 5.7% for non-BDE FRs, and 9.5% for OCPs. Recoveries of target chemicals

126

from each group were determined by spiking three clean PUFs with 1 mL working standard (20

127

ng/mL) and treating them as real samples. Recoveries ranged from 88% to 119% for PBDEs, 78%

128

to 130% for non-BDE FRs, and 63% to 100% for OCPs (Table S3). No blank-correction or

129

recovery adjustment was made.

130 131

Back trajectory analysis. Back-trajectories were calculated using the US NOAA Hybrid

132

Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with GDAS one-degree

133

archive meteorological data. Ten-day trajectories were calculated for air arriving at 200 m above

134

the earth’s surface starting every 6 h backwards in time. The coordinates of the calculated

135

trajectory points were recorded at 1 h time intervals. Trajectories were calculated for each

136

sampling period. Hierarchical cluster analysis was used to classify the backward air trajectories

137

into similar groups. Potential source contribution function (PSCF) for abundant chemicals was

138

computed by MetCor [12] v1.0 in 0.2° × 0.2° grid cells for northern hemisphere; monthly

139

concentrations were tagged to the back trajectory endpoints. Visualizations of the PSCF were

140

mapped using the Matlab 2012a.

141 142

Results and discussion

143

PBDEs. As shown in Fig. 1a, the total concentration of 14 PBDEs ranged from 0.42 to 18

144

pg/m3, with median value of 1.6 pg/m3. BDE-47 and -99 were the predominant PBDEs,

145

accounting for about 65% of total 14 PBDEs detected in the LFL atmosphere, with the median

146

concentration of 0.65 and 0.40 pg/m3, respectively. Commercial penta-BDE is a congener

147

combination of different PBDEs, with BDE-47 and -99 as the most abundant congeners. The

148

high levels of BDE-47 and -99 suggest penta-BDE mixtures to be the major influence on PBDEs

149

in air at LFL. BDE-28, -100 and -183 were also detected in most samples. BDE-17, -49, -71, -66,

150

-85, -154 and -153 were frequently detected before April 2013.

151

The concentrations of individual PBDE congener showed different profiles. The median

152

concentrations of BDE-47, -99 and -100 showed sharp decline in 2013 and 2014 (Fig. 1b), with

153

annual percent decline of 71 and 38% (BDE-47), 77 and 13% (BDE-99), 75 and 14% (BDE-100),

6 ACS Paragon Plus Environment

Page 7 of 20

Environmental Science & Technology

154

respectively. The medians of other PBDEs significantly decreased in 2013 (p 75% of the samples; PBEB was detected in

173

60% of the samples (Fig. 2 and Fig. S1); TBPH was detectable in ~40% of the samples and

174

frequently detected before 2013; ATE, BATE and BTBPE were detectable in ~25% of the

175

samples; HBCD was only found in two samples.

176

PBT was detected in all the samples, with concentrations ranging from 0.007 to 0.47 pg/m3,

177

with an average of 0.084 pg/m3. The mean concentrations of HBB and PBEB were 0.023 and

178

0.013 pg/m3, respectively. They were reported in European Arctic air with median values of 0.12

179

and 0.03 pg/m3, respectively [17].

180

ATE, BATE, DPTE and BTBPE are usually discussed together, because they are

181

synthesized from 2,4,6-tribromophenol (TBP), commercially known as PH-73 FF [18, 19].

182

Within this group, DPTE was detected in most samples, with median concentrations of 0.031

183

pg/m3, and was previously reported at levels ranging from 0.009 to 1.7 pg/m3 in the East

184

Greenland Sea atmosphere [15]. BATE was detected at the lowest concentration and detection 7 ACS Paragon Plus Environment

Environmental Science & Technology

185

frequency, with a maximum of 0.021 pg/m3. BATE was reported in air around the Great Lakes

186

ranging from 0.012 to 3.9 pg/m3 [18]. ATE and BTBPE were detected in fewer samples with

187

lower concentrations compared to Alert and the Tibetan plateau [14]. These results in our study

188

are also lower than those reported for the Arctic Ocean in summer 2010 [20].

189

Firemaster 550 and Firemaster BZ-54, as alternative FRs, were used since 2004. Firemaster

190

550 consists of about 35% of EH-TBB and about 15% of TBPH. Firemaster BZ-54 consists of

191

about 70% of EH-TBB and about 30% of TBPH [21]. In this study, EH-TBB and TBPH were

192

detected in 78% and 38% of all samples, with average concentrations of 0.20 and 0.33 pg/m3,

193

respectively. The average ratio of EH-TBB/TBPH from LFL air is 0.94, which is lower than 2.3

194

in Toronto, Canada [19], but similar to other sites around Great Lakes ranging from 0.70 to 1.2

195

[21, 22].

196

Four highly chlorinated FRs, dechlorane 602 and 604, syn- and anti-DP, were measured in

197

this study. The total concentrations of syn- and anti-DP ranged from 0.01 to 1.8 pg/m3, with

198

average of 0.11 and 0.14 pg/m3, respectively. The average proportion of anti-DP of the total DP

199

(Fanti) for the first year was 61%, similar to composition of technical DP (65%) [23], the mean

200

Fanti decrease to 56 and 51% in the second and third year. Moreover, the concentrations of DPs

201

also decreased over the 3 years, indicating that LFL may be more influenced by local emission in

202

the first year. These results are similar to the outcomes of Xiao et al. [14] and Moller et al. [24],

203

who reported the concentration ranges of < 0.05 to 2.1 pg/m3 at Alert, and 0.05 to 4.2 pg/m3 in

204

East Greenland. Dechlorane 602 was detectable in > 75% of the samples with a maximum of

205

0.06 pg/m3, while dechlorane 604 was only detected in 2014. As far as the authors are aware, this

206

is the first time that dechlorane 602 and 604 are reported in Arctic air.

207

PBDEs and OCPs have been detected in East Greenland polar bears for 3 decades [25, 26].

208

PBT and HBB have been found in eggs and plasma from glaucous gulls in the Norwegian Arctic

209

collected in 2006 [27]. Recently, Vorkamp et al. [28] reported that EH-TBB, TBPH, BTBPE,

210

DPTE and DPs were detectable in polar bear, ringed seal, black guillemot and glaucous gull

211

from Greenland. HBB and PBEB were also found in polar bears [29], indicating the potential for

212

LRAT and bioaccumulation of these novel FRs.

213

Page 8 of 20

Pearson correlations between compounds were used to examine if they have similar sources.

214

The results showed that BDE-47, -99, and -100 were significantly correlated with one another (r >

215

0.9, p < 0.0001, n=3) but not with BDE-183 (r < 0.3, p > 0.1, n=3). BDE-47 was also 8 ACS Paragon Plus Environment

Page 9 of 20

Environmental Science & Technology

216

significantly correlated with dechlorane 602 and EH-TBB (r > 0.45, p < 0.01, n=2), suggesting

217

similar sources. For the non-BDEs FRs, syn- and anti-DP were highly correlated (r = 0.967, p