Decabromodiphenyl Ether (DecaBDE) in Electrical and Electronic

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Decabromodiphenyl Ether (DecaBDE) in Electrical and Electronic Equipment in Japan: Stock, Emission, and Substitution Evaluation Mianqiang Xue, Liang Zhou, Naoya Kojima, Takashi Machimura, and Akihiro Tokai Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b03656 • Publication Date (Web): 20 Oct 2017 Downloaded from http://pubs.acs.org on October 23, 2017

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Environmental Science & Technology

1

Decabromodiphenyl Ether (DecaBDE) in Electrical and

2

Electronic Equipment in Japan: Stock, Emission, and

3

Substitution Evaluation

4

Mianqiang Xue∗ Liang Zhou, Naoya Kojima, Takashi Machimura, Akihiro Tokai

5

Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering,

6

Osaka University, 2-1 Yamadaoka, Suita, Osaka 565 0871, Japan

7 8

TOC art

9 10

ABSTRACT

11

DecaBDE has been widely used as flame retardant in electrical and electronic equipment

12

(EEE). It has recently been listed in Annex A of the Stockholm Convention. The time series

13

flow, stock, and emission of DecaBDE in EEE in Japan were quantified. On this basis, a

14

risk/risk trade-off analysis of substituting DecaBDE with triphenyl phosphate (TPhP) that is

Corresponding author: Mianqiang Xue, Tel:+81 06 68797677; Fax:+81 06 68797677; E-mail: [email protected]

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ACS Paragon Plus Environment


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15

one possible phosphorus-based alternative was conducted. The stock of DecaBDE reached a

16

maximum of ~42,000 t in 1995. Even though the demand flow was negligible in 2030, the

17

stock was modelled to be still ~470 t. The outflow of DecaBDE, from the use phase to the

18

disposal phase, peaked at ~4,500 t/yr. in 2001. The DecaBDE emission to atmosphere was

19

mainly derived from the production phase before 1990. The use phase became the largest

20

contributor to the total emission from 1995 to 2000. Whereas the disposal phase dominated

21

the total emission from 2000 onwards. In the substitution analysis, a trade-off between human

22

and ecological health effect was revealed in case of replacing DecaBDE with TPhP. This

23

study attempted to give an overall picture of DecaBDE application at national level providing

24

insights into relevant environmental policy making.

25

1. INTRODUCTION

26

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in a

27

variety of products since 1970s. There are primarily three technical formulations of PBDEs:

28

PentaBDE, OctaBDE and DecaBDE

29

the Stockholm Convention in 2009 and have been phased out worldwide

30

just listed in Annex A of the Stockholm Convention in 2017 with specific exemptions for

31

production and use

32

mixture still being used today (4). More than one million tons of DecaBDE was produced from

33

1970 to 2010 globally

34

maximum of 10,000 t/yr. in 1990 (6). Since then, it decreased due to voluntary phase down by

35

the industry sector. DecaBDE is ubiquitous in the environment because of its widespread use

36

(7)

(1)

. PentaBDE and OctaBDE were added to Annex A of (2)

. DecaBDE was

(3)

. It might bioaccumulate in wildlife and human and is the only PBDEs

(5)

. The domestic consumption of DecaBDE in Japan reached a

and thus much concern has been raised (8, 9).

-2-


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(1)

37

About 70% of DecaBDE is used in electrical and electronic equipment (EEE)

.

38

DecaBDE, locked in EEE with a long lifespan, has a long residence time in society. Stock of

39

DecaBDE in the use phase results in disconnection between the inflow and outflow of a

40

system in one year

41

materials. It can be released throughout the life cycle of EEE to all environmental

42

compartments including the atmosphere, hydrosphere and pedosphere. Stocks and flows of

43

PBDEs in products in the U.S. and Canada from 1970 to 2020 were estimated based on the

44

consumption pattern, PBDE content and product lifespan

45

analysis of brominated flame retardants was performed for Switzerland from 1980 to 2020 (12).

46

Flows of DecaBDE and other flame retardants in a waste EEE treatment plant was

47

characterized

48

employing a population balance model considering future regulation (14). Besides, atmospheric

49

emissions of DecaBDE were calculated using emission factors derived from field study

50

The knowledge of DecaBDE flows and stocks is essential for identifying major sources and

51

final sinks. Source identification and emission quantification of DecaBDE serve as a good

52

basis for subsequent risk assessment. It is thus significant for improving strategies and

53

revealing opportunities for DecaBDE sound management. Nevertheless, only limited

54

comprehensive information is available regarding emissions of DecaBDE in EEE to all

55

environmental compartments.

(10)

. DecaBDE is an additive since it is not chemically bound to host

(11)

. A dynamic substance flow

(13)

. PBDEs stock and atmospheric emissions in Japan were evaluated by

(6)

.

56

Due to curtailed use of DecaBDE in Japan, other alternative flame retardants have been

57

used to reduce the risk of DecaBDE while still meeting fire safety standards. Triphenyl

58

phosphate (TPhP), a phosphorus flame retardant, has been identified as one possible

-3-



(15, 16)

. However, the substitute is also problematic

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(17, 18)

59

substitute for DecaBDE

and has

60

recently been included in the community rolling action plan (CoRAP) in the EU as a

61

suspected endocrine disruptor

62

exposure and reduced fertility

63

countervailing risks at the same time. The countervailing risk could partially or completely

64

offset reductions in the target risk (21, 22). The cases in which substituting chemicals pose more

65

adverse impacts to humans and the environment than the substituted chemicals are

66

unacceptable. Sound decision-making process with uncertainty requires examinations of

67

DecaBDE replacement in EEE and always attempts to mitigate risk/risk trade-offs.

(19)

. A recent study indicated a relationship between TPhP

(20)

. Efforts to reduce one risk might create new or exacerbate

68

In the present study, we investigated the time dependent flows, stocks, emissions and

69

effects of DecaBDE in EEE in Japan. Further, we conducted risk/risk trade-off analysis in

70

terms of substituting DecaBDE with TPhP based on scenario analysis. The main objectives of

71

this work are (1) to provide a holistic picture of DecaBDE application from which lessons can

72

be learned for analogous chemicals management; and (2) to conduct relative evaluation of

73

DecaBDE substitution based on the flow and stock model exploring challenges of preferable

74

alternatives identification.

75

2. MATERIALS AND METHODS

76

2.1 Flow and Stock Modeling

77

Figure 1 illustrates the research framework for modelling the flows, stocks, emissions

78

and effects of DecaBDE in EEE. The geographic boundary is Japan and the time period is

79

from 1976 to 2030. First, the flow and stock of DecaBDE were calculated using dynamic

80

substance flow analysis taking into account changes over time. In principle, the life cycle of

-4-


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DecaBDE is divided into the production, use and disposal phase. The production phase

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consists of DecaBDE and EEE production process. The use phase means usage of EEE

83

containing DecaBDE. The disposal phase includes recycling, incineration, sewage and

84

landfilling. Second, DecaBDE emissions from each life cycle process to each environmental

85

compartment were investigated on the basis of the foregoing flow and stock analysis. Third,

86

effects of released DecaBDE were quantified using LIME2 (23), the Japanese life cycle impact

87

assessment approach. By means of transforming effects into one common indicator, a risk/risk

88

trade-off analysis was conducted in case of replacing DecaBDE with TPhP. The concrete

89

methods will be presented in detail below.

90 91

Figure 1. Research framework for modelling the flows, stocks, emissions and effects of DecaBDE in

92

EEE in Japan.

93

DecaBDE accompanying with EEE flows into the use phase and accumulates as stock.

94

At the end of lives of EEE, DecaBDE flows out and are treated in the disposal phase. The

95

inflow of DecaBDE was calculated by employing data on domestic demand of DecaBDE in

96

Japan (domestic production + import - export) (24, 25). These data can be found in Table S1-2 in

97

the Supporting Information (SI). DecaBDE began to be used for EEE in Japan in 1977 (24). In -5-



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98

the present study, the Weibull statistical distribution was used for describing the lifespan of

99

EEE as shown in Eq. (1) (26):

100

α p(t , t0 ) = ⋅ (t − t0 )α − 1 ⋅ e α β

−(

t − t0

β

)α

(1)

101

where p (t, t0) is the probability of EEE to be obsoleted in the evaluation year t for those

102

purchased in historical year t0; α is the shape parameter; β is the scale parameter; The shape

103

parameter is 3.7 and the scale parameter is 11.2 for EEE (24). t is the evaluation year; t0 is the

104

historical year in which EEE were purchased. Then, the stock of DecaBDE in the use phase

105

over time can be calculated by Eq. (2): T

106

T

 S1977   I1977  1 − P(1977 ,1977 ) 1 − P(1978 ,1977 ) L 1 − P( t ,1977 ) S  I   1 − P(1978,1978) K 1 − P( t ,1979 )  1978   1978   O L  M   M     =  × 1 − P(t ,t 0 )  St   It    M   M   M      0 L  S 2030   I 2030  

L 1 − P( 2030,1977 )  L 1 − P( 2030 ,1978 )   L L  L L   O L  1 − P( 2030, 2030 ) 

(2)

107

where St is the stock of DecaBDE in year t; It is the inflow of DecaBDE in year t; P(t, t0) is the

108

cumulative Weibull distribution; 1- P(t, t0) is the complementary Weibull distribution, i.e., the

109

probability that EEE containing DecaBDE remains in the use phase in evaluation year t for

110

those purchased in historical year t0. Based on the law of mass conservation, the outflow of

111

DecaBDE into the disposal phase over time can be obtained by Eq. (3):

112

Ot = It − (St − St −1 )

(3)

113

where Ot is the outflow of DecaBDE in year t; It is the inflow of DecaBDE in year t; St and

114

St-1 are the stock of DecaBDE in year t and t-1, respectively.

115

2.2 Emission Inventory

116

DecaBDE can be emitted from each life cycle process (DecaBDE production, EEE

-6-


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production, use, recycling, sewage, incineration and landfill) to each environmental

118

compartment (atmosphere, hydrosphere and pedosphere). Emissions of DecaBDE were

119

quantified by Eq. (4):

120

Eij=A . EFij

(4)

121

where Eij is the emission of DecaBDE from the life cycle process i to the environmental

122

compartment j; A is the activity associated with emission of DecaBDE which is usually a

123

mass flow; EFij is the emission factor from the life cycle process i to the environmental

124

compartment j. In particular, the activities in the DecaBDE production, EEE production and

125

use process are corresponding to the domestic production flow, domestic demand flow and

126

in-use stock, respectively. During the DecaBDE and EEE production, DecaBDE in waste

127

water will be transferred to sewage system whereas solid waste containing DecaBDE will be

128

treated as industrial waste. Outflows from the use phase to the disposal phase were mainly

129

managed by four approaches: export, recycling, treated as general waste and industrial waste

130

(27)

131

appliances recycling law was put into force in Japan (28). In the years before 2001, 70% of the

132

outflow was treated as general waste. After 2001, 50% of the outflow was recycled and the

133

left 20% was treated as industrial waste. For general waste, 84% was disposed by incineration

134

while 16% was disposed by landfill. For industrial waste, 38.1% was disposed by incineration

135

while 61.9% was disposed by landfill

136

cycle are represented in Figure 1. The emission and transfer factors of DecaBDE are

137

presented in Table S3.

138

. Basically, 30% of the outflow was exported to other countries. In 2001, the home

(24)

. The transfer routes of DecaBDE through its life

In practice, emission factors are usually supposed to be representatives of the average

-7-



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emission rate. Lack of understanding about emission factors might result in erroneous

140

inferences. The two-dimensional probabilistic technique enables us to quantify variability and

141

uncertainty simultaneously, providing additional insights into environmental decision-making

142

(29)

143

evaluating its central tendency and dispersion, as described in SI. Then, a parametric

144

probability distribution was selected to fit to the data for denoting variability in the emission

145

factor. The parameters of the distribution were determined using the maximum likelihood

146

estimation. Afterwards, uncertainty in the distribution was quantified using parametric

147

bootstrap simulation (30), a numerical approach for estimating confidence intervals on the basis

148

of simulation of random sampling error. This method is particularly applicable in the case of

149

small sample size and skewed data. It was assumed that the emission factors were continuous

150

random variables. A random sample of the same size as the original dataset was simulated

151

from sampling this fitted model. It was done with replacement. The bootstrapping was

152

repeated for 2000 times making it sufficient to obtain accurate confidence intervals (31).

. For a set of data, it was firstly visualized by the method of “plotting position” for

153

To identify the most highly sensitive input variables responsible for variability and

154

uncertainty in the system, an initial sensitivity analysis was carried out. The sensitivity ratios

155

were calculated by Eq. (5) (32):

156

Y2 − Y1 Y1 SR = X2 − X1 X1

(5)

157

where X1 is the reference value of one input variable; X2 is 115% of X1 in this study; Y1 and Y2

158

are the output variables with X1 and X2 as input variables, respectively.

159

2.3 Substitution Scenarios and Risk/risk Trade-off Analysis

-8-


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Substitution scenarios were developed as a basis for risk/risk trade-off analysis,

161

investigating how the countervailing risk offset the target risk reduction. In the present study,

162

three scenarios were developed: Scenario A was the best estimation of flows, stocks,

163

emissions and effects of DecaBDE. It was estimated as close to the actual situation as possible

164

employing currently available data, seen in Section 2.1. Whereas Scenario B and C were

165

designed with a purpose of comparison. Specifically, Scenario B assumed a case in which

166

there was no substitution for DecaBDE. The domestic demand of DecaBDE would remain the

167

same since 1990. Scenario C was a case in which DecaBDE (difference between Scenario A

168

and Scenario B) was substituted with TPhP. The amount of TPhP was calculated according to

169

the ratio of TPhP and DecaBDE contents in EEE

170

scenarios intuitively. Then, the risk/risk trade-off can be analyzed by comparing Scenario

171

A+C with Scenario B. Table 1 shows the properties of DecaBDE and TPhP. We notice the

172

difference in use and emission patterns. Emission factors in preparing plastics with TPhP for

173

EEE and in the use phase were supposed to be in proportion to the vapor pressure. In the

174

recycling process, it was in proportion to its content in plastics. Other factors without

175

information were assumed to be identical to that of DecaBDE seen in Table S3.

(27)

. Figure S1 illustrates these substitution

176

In each scenario, the fates, exposures and effects of DecaBDE and TPhP were signified

177

by damage factors. The effects were expressed in the Eco-indicator after integration. The

178

Eco-indicator with a unit of Japanese Yen was calculated by Eq. (6):

179

EI=Ei . DFij . IFij

(6)

180

where EI is the Eco-indicator; Ei is the emission of chemical i; DFij is the damage factor of

181

chemical i emissions to the environmental compartment j; IFij is the corresponding integration

-9-



182

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factor. The damage and integration factors used in this study can be seen in Table S4. Table 1. The Physical Properties of DecaBDE and TPhP a

Chemicals

a

CAS number

Molecular mass

Vapor pressure

Water solubility

(g/mol)

(Pa)

(mol/m3)

Structure

DecaBDE

1163-19-5

959

4.63E-06

1.04E-07

TPhP

115-86-6

326

8.37E-04

5.82E-03

The vapor pressure and water solubility were taken from Watanabe et al. (27)

183

3. RESULTS AND DISCUSSION

184

3.1 Flow and Stock of DecaBDE

185

Figure 2 illustrates the time series flow and stock of DecaBDE in EEE in Japan. It

186

represents a typical flow pattern of a chemical substance that was phased down because of

187

health risk concerns. The domestic demand flow of DecaBDE increased sharply until a peak

188

of 8000 t/yr. was reached in 1990. Since then, DecaBDE was phased down progressively and

189

the demand flow decreased rapidly. Compared with the domestic demand flow, the domestic

190

production flow was small indicating a large portion of importation of DecaBDE.

191

In regard to the stock of DecaBDE, it appeared in a same trend with demand flow. Two

192

distinct features were observed. One was that the stock of DecaBDE was huge. It reached a

193

maximum of ~42,000 t in 1995. The other was that the peak year of stock was delayed for

194

five years. Even though the demand flow was negligible in 2030, the stock was modelled to

195

be still ~470 t. It indicated that the role of stock is significant in risk management of

196

thousands of chemicals used in our society from the life cycle perspective.

197

The outflow of DecaBDE, from the use phase to the disposal phase, increased firstly

-10-


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198

followed by a smooth decline with a peak value of ~4,500 t/yr. in 2001. Results of the stock

199

and outflow provide insights into consumer exposure risk appraisal and strategic planning for

200

waste management.

201 202 203

Figure 2. Flow and stock of DecaBDE in EEE in Japan from 1976 to 2030.

3.2 Emissions of DecaBDE

204

Based upon the foregoing analysis of flow and stock, emissions of DecaBDE were

205

quantified. From a static perspective, a snapshot of DecaBDE emission with a time scale of

206

one year was studied to identify the emissions from which life cycle process to which

207

environmental compartment. As an example, Figure 3 presents the DecaBDE emission in

208

2003 in Sankey diagram, in which the width of the arrow is proportionally to the flow

209

quantity. The total emission of DecaBDE was 157 t in 2003. The emissions were primarily

210

from the production phase to hydrosphere.

211

If we look at the emission sources, the production phase contributed most significantly to

212

the total emission with a value of 63%. Likewise, the use and disposal phases contributed 9%

213

and 28%, respectively. For the disposal phase, the emission was largely attributed to the

214

treatment methods of recycling (62%) and incineration (24%). If we look at the receiving

215

environmental compartments, 59% of the total emissions were released into hydrosphere and

-11-



216

38% into atmosphere. The left small fraction was released into pedosphere.

217 218

Figure 3. Sankey diagram of DecaBDE emissions from each life cycle phase to each

219

environmental compartment.

220

On the other hand, from a dynamic perspective, the time series emission of DecaBDE

221

from 1976 to 2030 was computed to investigate its changing behavior, as shown in Figure 4.

222

For the DecaBDE emission to atmosphere, it was mainly derived from the production phase

223

before the year 1990. Interestingly, the use phase became the largest contributor to the total

224

emission from 1995 to 2000. Whereas, it revealed that the disposal phase dominated the total

225

emission from 2000 onwards. This transformation of primary emission sources can be

226

explained by dynamics of the flow and stock. The emission from the production phase peaked

227

at about 0.11 t/yr. in 1990. The emission from the use phase peaked at 0.031 t/yr. in 1995. The

228

emission from the disposal phase peaked at 0.041 t/yr. in 2002.

229

With respect to the DecaBDE emission to hydrosphere, the production always played a

230

dominant role over the time range of this study. The emission attributable to the production

231

phase was larger than 0.1 t/yr. from 1982 to 2000. In contrast, both of contributions from the

232

use and disposal phase were pretty small. In regard to the DecaBDE emission to pedosphere,

233

the disposal phase had absolute predominance compared with the production and use phase. -12-


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234 235

Figure 4. The emissions of DecaBDE in EEE in Japan from 1976 to 2030, breakdown by life

236

cycle phase: (a) to atmosphere, (b) to hydrosphere, (c) to pedosphere.

237

DecaBDE emissions are subjected to both variability and uncertainty. Variability refers

238

to the real differences in values, whereas uncertainty is a lack of knowledge regarding the true

239

value. In the present work, we quantified variability and uncertainty simultaneously to better

240

understand the precision of the modelling.

241

In a first step, the sensitivity ratios were calculated. It was found that the sensitivity ratio

242

for the emission factor from the production phase to hydrosphere was the highest (0.61) in the

243

case of +15% error in variables. The sensitivity ratios for other emission factors were small.

244

For the emission factor from the production phase to hydrosphere, a set of data was collected

-13-



245

and plotted in Figure 5. A lognormal probability distribution was fit to data points denoting

246

the variability. It indicated that 95% of the emission factors from the production phase to

247

hydrosphere range from 3.6E-05 to 3.1E-03. On the basis of the fitted distribution for

248

variability, the 50%, 90% and 95% confidence intervals were obtained by bootstrap

249

simulation to inspect the appropriateness. The results implied that 83% of the data points were

250

enclosed by the 50% confidence interval for the fitted distribution. And 100% of the data

251

points were enclosed by the 95% confidence interval.

252 253

Figure 5. Variability and uncertainty in the DecaBDE emission factor from the production

254

process to hydrosphere.

255

Through the two-dimensional probabilistic analysis, we can identify any percentile of the

256

factor with any confidence interval. The 95% confidence interval is usually of particular

257

interest and in this study all of the data points are enclosed by this confidence interval. As an

258

example, the total emission of DecaBDE was calculated using the 50 percentile of the

259

emission factor from the production phase to hydrosphere with the 95% confidence interval,

260

as shown in Figure 6. The total DecaBDE emission reached a maximum of 0.50 (0.31-1.13)

261

t/yr.in 1990. Prior to that from 1980 to 1990, the total emission increased with an average -14-


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262

annual rate of 66%. After that from 1990 to 2000, the total emission decreased with an

263

average annual rate of 6%.

264 265

Figure 6. Total emissions of DecaBDE in EEE in Japan from 1977 to 2030: line, mean value

266

of emission factors; shaded area, 2.5th and 97.5th percentiles.

267

3.3 Substitution and Risk/risk Trade-off

268

To compare the risk related usage of DecaBDE and its candidate substitution TPhP, a

269

risk/risk trade-off analysis was conducted based on substitution scenarios. Figure 7 presents

270

the Eco-indicators of DecaBDE and TPhP from EEE in Japan from 1976 to 2030. The

271

endpoints include both human and ecological health effects. It can be found that the

272

Eco-indicator decreased significantly since 1990 when DecaBDE was replaced with TPhP

273

from the standpoint of protection of humans and the environment. If DecaBDE was

274

continuously being used, the Eco-indicator would be 6.6E+07 Yen in 2030. If DecaBDE was

275

replaced with TPhP, the Eco-indicator would be 5.6E+06 Yen in 2030. In the case of replacing

276

DecaBDE with TPhP, the Eco-indicator was mainly attributable to the human health effect of

277

DecaBDE and the ecological health effect of TPhP.

-15-



278 279

Figure 7. Eco-indicators of DecaBDE and TPhP in EEE in Japan from 1976 to 2030.

280

It is of importance to define the time frame to do trade-off analysis. In this study,

281

DecaBDE was firstly introduced for EEE in Japan in 1970s. It began to be replaced with

282

alternatives in 1990. Based on the developed scenarios, the trade-off of replacing DecaBDE

283

with TPhP in the year 2030 was demonstrated in Figure 8. The green color represented the

284

preferable area while the red color represented the undesirable area. It revealed that the

285

human health effects decreased whereas the ecological health effects increased at the same

286

time. Namely, a trade-off between human and ecological health effects was identified, which

287

was resulted from risk offset and transformation.

288 289 290

Figure 8. Risk/risk trade-off analysis of replacing DecaBDE with TPhP in the year 2030. In sum, the present study evaluated the stock, emission and substitution of DecaBDE in -16-


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291

EEE in Japan retrospectively and prospectively from 1976 to 2030. It attempted to give an

292

overall picture of DecaBDE application at national level providing support for chemical

293

management. First, the DecaBDE stock in EEE reached a maximum of ~42,000 t in 1995.

294

Even though the demand flow was negligible in 2030, the stock was modelled to be still ~470

295

t. It indicated that phasing out of a chemical with potential harm is just one important first

296

step, once it was being widely applied in products. The subsequent stock and waste

297

management also should be tackled with proper countermeasures. Second, a transformation of

298

the primary emission source of DecaBDE over time was identified. It suggested that

299

corresponding remedies in a timely manner were required in different periods from

300

introduction, through widely use, to phasing out of DecaBDE. Third, the two-dimensional

301

probabilistic analysis quantified both variability and uncertainty of the most sensitive

302

emission factor. It offered additional information about whether the modelling was good

303

enough for decision-making. Fourth, a broad decision framework is important regarding

304

chemical substitution to mitigate risk/risk trade-offs. Finally, combination of the dynamic

305

substance analysis and risk evaluation techniques enables us to evaluate the time-dependent

306

chemical substitution, which is very helpful for efficient and effective chemical management.

307

However, this study has some limitations. There are significant uncertainties in emission

308

factors from each life cycle process to each environmental compartment, calling for further

309

experiment and model based studies. The substitution evaluation conducted by LIME2 should

310

be understood as relative analysis, which is not suitable to answer the question whether or not

311

the substitute is safe. It provides insights for screening level decisions rather than directly for

312

laws and regulations. The elaborate fate process and exposure scenarios were out of the scope

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313

of this work and here they were addressed by integrating them into damage factors. It is also

314

worth noting that the environmental risks of both DecaBDE and TPhP are still ongoing. Their

315

effects on vulnerable populations and occupational workers should not be underestimated.

316

ASSOCIATED CONTENT

317

Supporting Information

318

Additional details on the raw data and results. This information is available free of charge via

319

the Internet at http://pubs.acs.org.

320

Notes

321

The authors declare they have no competing financial interest.

322

ACKNOWLEDGMENTS

323

This research was supported by the Environment Research Technology Development Fund

324

(1-1501) of the Ministry of Environment, Japan. We express our appreciation to the members

325

of the Risk Governance Project Expert Committee. We also thank the anonymous reviewers

326

for their valuable suggestions to improve the quality of the paper.

327

REFERENCES

328

(1) Li, J.; Chen, Y.; Xiao, W. Polybrominated diphenyl ethers in articles: a review of its

329 330 331

applications and legislation. Environ. Sci. Pollut. Res. 2017, 24, 4312-4321. (2) UNEP. Fourth Meeting of the Conference of the Parties to the Stockholm Convention on Persistent Organic Pollutants. 2009. http://chm.pops.int/Home (accessed May 24, 2017).

332

(3) IISD. Summary of the Meetings of the Conferences of the Parties to the Basel, Rotterdam

333

and Stockholm Conventions: 24 April - 5 May 2017; The International Institute for

334

Sustainable Development Reporting Services, Earth Negotiations Bulletin: New York,

-18-


Page 18 of 22

Page 19 of 22


335

USA, 2017. http://enb.iisd.org/download/pdf/enb15252e.pdf (accessed September 13,

336

2017).

337

(4) Zhang, Z.; Sun, Z.; Xiao, X.; Zhou, S.; Wang, X.; Gu, J.; Qiu, L.; Zhang, X.; Xu, Q.;

338

Zhen, B.; Wang, X.; Wang, S. Mechanism of BDE209-induced impaired glucose

339

homeostasis based on gene microarray analysis of adult rat liver. Arch. Toxicol. 2013, 87,

340

1557-1567.

341 342

(5) Earnshaw, M.; Jones, K.; Sweetman, A. A first European scale multimedia fate modelling of BDE-209 from 1970 to 2020. Environ. Int. 2015, 74, 71-81.

343

(6) Sakai, S.; Hirai, Y.; Aizawa, H.; Ota, S.; Muroishi, Y. Emission inventory of

344

deca-brominated diphenyl ether (DBDE) in Japan. J. Mater. Cycles Waste Manag. 2006, 8,

345

56-62.

346

(7) Li, Y.; Qiao, L.; Ren, N.; Sverko, E.; Mackay, D.; Macdonald, R. Decabrominated

347

diphenyl ethers (BDE-209) in Chinese and global air: Levels, gas/particle partitioning,

348

and long-range transport: Is long range transport of BDE-209 really governed by the

349

movement of particles? Environ. Sci. Technol. 2017, 51, 1035−1042.

350 351 352

(8) ECHA. Decision of the European Chemicals Agency, inclusion of substances of very high concern in the candidate list; ED/169/2012; 2012. (9) UNEP. Report of the Persistent Organic Pollutants Review Committee on the work of its

353

tenth

meeting;

UNEP/POPS/POPRC.10/10/Add.2;

354

Programme: Rome, 2014;

United

Nations

Environment

355

(10) Müller, E.; Hilty, L.; Widmer, R.; Schluep, M.; Faulstich, M. Modeling metal stocks and

356

flows: A review of dynamic material flow analysis methods. Environ. Sci. Technol. 2014,

-19-



357

Page 20 of 22

48, 2102-2113.

358

(11) Abbasi, G.; Buser, A. M.; Soehl, A.; Murray, M. W.; Diamond, M. L. Stocks and flows of

359

PBDEs in products from use to waste in the U.S. and Canada from 1970 to 2020. Environ.

360

Sci. Technol. 2015, 49, 1521-1528.

361

(12) Morf, L.; Buser, A.; Taverna, R.; Bader, H.; Scheidegger, R. Dynamic substance flow

362

analysis as a valuable risk evaluation tool-A case study for brominated flame retardants as

363

an example of potential endocrine disrupters. Chimia, 2008, 62, 424-431.

364

(13) Morf, L.; Tremp, J.; Gloor, R.; Huber, Y.; Stengele, M.; Zennegg, M. Brominated flame

365

retardants in waste electrical and electronic equipment: substance flows in a recycling

366

plant. Environ. Sci. Technol. 2005, 39, 8691-8699.

367 368 369 370

(14) Dien, N.; Hirai, Y.; Sakai, S. In-use polybrominated diphenyl ether (PBDE) stocks and atmospheric emissions in Japan. J. Mater. Cycles Waste Manag. 2017, 1-9. (15) van der Veen, I.; de Boer, J. Phosphorus flame retardants: properties, production, environmental occurrence, toxicity and analysis. Chemosphere 2012, 88, 1119-1153.

371

(16) Zhang, Q.; Lu, M.; Dong, X.; Wang, C.; Zhang, C.; Liu, W.; Zhao, M. Potential

372

estrogenic effects of phosphorus-containing flame retardants. Environ. Sci. Technol. 2014,

373

48, 6995-7001.

374

(17) Ma, Y.; Xie, Z.; Lohmann, R.; Mi, W.; Gao, G. Organophosphate Ester Flame Retardants

375

and Plasticizers in Ocean Sediments from the North Pacific to the Arctic Ocean. Environ.

376

Sci. Technol. 2017, 51, 3809-3815.

377 378

(18) U.S.

National

Library

of

Medicine,

toxicology

data

network

website.

https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+2536

-20-


Page 21 of 22


379 380

(accessed September 15, 2017) (19) ECHA. Justification for the selection of a candidate CoRAP substance. 2013.

381

https://echa.europa.eu/documents/10162/47fa7ee3-8323-4532-bb52-f1d8fe3b5ea4

382

(accessed September 14, 2017)

383

(20) Carignan, C.; Mínguez-Alarcón, L.; Butt, C.; Williams, P.; Meeker, J.; Stapleton, H.;

384

Toth, T.; Ford, J.; Hauser, H. Urinary concentrations of organophosphate flame retardant

385

metabolites and pregnancy outcomes among women undergoing in vitro fertilization.

386

Environ. Health Perspect. 2017, 125, 087018 1-8.

387

(21) Gray, G.; Hammitt, J. Risk/Risk trade-offs in pesticide regulation: an exploratory analysis

388

of the public health effects of a ban on organophosphate and carbamate pesticides. Risk

389

Anal. 2000, 20, 665-680.

390 391 392 393 394 395 396 397

(22) Wiener, J.; Graham, J. Risk vs. Risk: Tradeoffs in protecting health and the environment; Harvard University Press: Cambridge, U.S., 2009. (23) Itsubo, N.; Inaba, A. LIME2: life-cycle impact assessment method based on endpoint modeling, Maruzen Publisher: Tokyo, Japan, 2010. (24) Nakanishi, J.; Tokai, A.; Iwata, M. Detailed risk assessment series 23 - Deca bromodiphenyl Ether, Maruzen Publisher: Tokyo, Japan, 2008. (25) Ministry of the environment, Japan (MOE). Survey results on brominated dioxins. 2015. https://www.env.go.jp/chemi/dioxin/chosa/shuki.html (accessed May 12, 2017).

398

(26) Xue, M.; Kojima, N.; Machimura, T.; Tokai, A. Flow, stock, and impact assessment of

399

refrigerants in the Japanese household air conditioner sector. Sci. Total Environ. 2017, 586,

400

1308-1315.

-21-



401

(27) Watanabe, S.; Nakakubo, T.; Tokai, A.; Yamamoto, Y. Risk evaluation method

402

formulation assisting industrial sector in voluntary chemicals management-a case study of

403

flame retardant in TV enclosures. Jap. J. Risk Anal. 2011, 21, 285-294.

404

(28) The Ministry of Economy, Trade and Industry in Japan (METI). Home Appliance

405

Recycling Law. http://www.meti.go.jp/policy/it_policy/kaden_recycle/ (accessed May 15,

406

2017).

407

(29) Frey, H.; Zhao, Y. Quantification of variability and uncertainty for air toxic emission

408

inventories with censored emission factor data. Environ. Sci. Technol. 2004, 38,

409

6094-6100.

410

(30) Efron, B. Bootstrap methods: Another look at the jackknife. Ann. Stat. 1979, 7, 1-26.

411

(31) Scheidt, C.; Caers, J. Bootstrap confidence intervals for reservoir model selection

412

techniques. Computat. Geosci. 2010, 14, 369-382.

413

(32) Yamaguchi, H.; Tokai, A. Two dimensional problematic estimation of environmental

414

emission load considering the quality of data, with the case of DecaBDE. Jap. J. Risk

415

Anal. 2008, 17, 75-83.

-22-


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