External Exposure to Short- and Medium-Chain Chlorinated

The distribution pattern in indoor dust was a result of CP52 technical mixtures shifting to lower-chain-CPs. C14 was the most abundant MCCP formula gr...
0 downloads 11 Views 1MB Size
Subscriber access provided by READING UNIV

Article

External Exposure to Short- and Medium-chain Chlorinated Paraffins for the General Population in Beijing, China Wei Gao, Dandan Cao, Yingjun Wang, Jing Wu, Ying Wang, Yawei Wang, and Guibin Jiang Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b04657 • Publication Date (Web): 30 Nov 2017 Downloaded from http://pubs.acs.org on December 3, 2017

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 33

Environmental Science & Technology

External Exposure to Short- and Medium-chain Chlorinated

1 2

Paraffins for the General Population in Beijing, China

3

Wei Gao1, 3, Dandan Cao1, Yingjun Wang1, 3, Jing Wu1, 3, Ying Wang1, Yawei Wang1, 2,

4

3

5

1

6

Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing

7

100085, China

8

2

Institute of Environment and Health, Jianghan University, Wuhan 430056, China

9

3

University of Chinese Academy of Sciences, Beijing 100049, China

,* and Guibin Jiang1 State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research

10 11 12 13

*Corresponding author

14

Dr. Yawei Wang

15

State Key Laboratory of Environmental Chemistry and Ecotoxicology

16

Research Center for Eco-Environmental Sciences

17

Chinese Academy of Sciences

18

P.O. Box 2871, Beijing 100085, China

19

Tel: +8610-6284-9124

20

Fax: +8610-6284-9339

21

E-mail: [email protected]

22

1

ACS Paragon Plus Environment

Environmental Science & Technology

23

Abstract

24

Chlorinated paraffins (CPs) are a class of compounds that are currently produced

25

and used in large amounts in commercial products worldwide. In this study, food,

26

indoor air, indoor dust and drinking water samples were collected to evaluate the

27

external exposure levels of CPs and possible pathway for the general population in

28

Beijing, China. Short chain CPs (SCCPs) and medium chain CPs (MCCPs) in 199

29

samples were analyzed using a gas chromatography tandem time-of-flight

30

high-resolution mass spectrometry (GC - TOF - HR -MS) method. High levels of CPs

31

were observed in the indoor environment from residential houses, offices and student

32

dormitories. The geometric mean concentrations (GM) of ∑SCCPs and ∑MCCPs in

33

indoor dust were 92 µg g-1 and 82 µg g-1, respectively, while in indoor air, the

34

concentrations were 80 ng m-3 and 3.4 ng m-3, respectively. The GM of ∑SCCPs and

35

∑MCCPs in the diet were 83 ng g-1 dry weight (dw) and 56 ng g-1 dw, respectively.

36

The most important external exposure routes to CPs to the general populations in

37

Beijing were food intake and indoor dust ingestion. Indoor dust and indoor air posed

38

higher risks for toddlers and infants than for adults.

39 40 41 42 43

2

ACS Paragon Plus Environment

Page 2 of 33

Page 3 of 33

Environmental Science & Technology

44 45

Table of Contents Figure

3

ACS Paragon Plus Environment

Environmental Science & Technology

46 47

Introduction Chlorinated paraffins (CPs) are a class of compounds currently produced and

48

used in large amounts in commercial products and can be divided into three categories:

49

short chain chlorinated paraffins (SCCPs, C10-C13), medium chain chlorinated

50

paraffins (MCCP, C14-C17), and long chain chlorinated paraffins (LCCP, C≥18).1,2 CPs

51

have been used as industrial additives for several decades.1 The current SCCPs

52

production worldwide was estimated to be at least 16,5000 t/year, while the total CPs

53

production volume was much higher as CPs products are mixtures of different chain

54

length CPs.3 China began to produce CP products in the 1950s3,4 and is the largest

55

producer in the world at present according to the data provided by the Chinese Chlor

56

Alkali Association. Researchers have paid special attention to SCCPs because of their

57

long-distance transport potential,5,6 persistence,7 bioaccumulation potential,8 and

58

possible carcinogenic effects.9 In 2006, SCCPs were proposed to be included in the

59

Stockholm Convention (SC) on Persistent Organic Pollutants (POPs).10 In 2016, at its

60

twelfth meeting, the POPs Review Committee ultimately considered that SCCPs

61

fulfilled the criteria of POPs and the eighth Conference of Parties decided to list

62

SCCPs in Annex A as new POPs in SC in May, 2017.11,12 Although SCCPs have been

63

listed in the SC, the exemptions for SCCPs applications in the document allowed

64

SCCPs existence in the environment for a relatively long period. Moreover, MCCPs

65

might have equally significant adverse environmental and human health effects

66

because their persistence and bioaccumulation properties were similar to SCCPs.13

67

However, compared to SCCPs, data on MCCPs levels in environment and even for 4

ACS Paragon Plus Environment

Page 4 of 33

Page 5 of 33

Environmental Science & Technology

68

human exposure are relative scarce as a result of lack of enough attention. Risk

69

quotients of MCCPs should also be considered in future studies to address data gaps

70

relevant to the exposure of the general population to CPs.

71

CPs have been found in various environmental matrices at high levels in China,

72

including soil, air, biota, food, water, and even in human milk since China is the

73

largest CP producing country.14-22 Our previous studies found high concentrations of

74

SCCPs in the outdoor and indoor atmosphere in Beijing, China.15,17 Harada et al.

75

found that concentrations of SCCPs in the diet increased by two orders of magnitude

76

from the 1990s to 2009 in Beijing, China.23 In addition, a recent work found relatively

77

high levels of SCCPs and MCCPs in human milk from urban areas in 28 Chinese

78

provinces.24 All these studies implied that the general population in China may be

79

facing high external exposure to CPs in the living environment. However, the possible

80

routes and sources of CPs have not been well evaluated.

81

In this study, congener group distributions and levels of SCCPs and MCCPs

82

were studied simultaneously in indoor dust and indoor air from residential houses and

83

workplaces, duplicate food samples from participants and fast-food outlets, and

84

drinking water by a GC--TOF-HRMS method. The purpose of this study was to study

85

the congener profiles and the concentrations of SCCPs and MCCPs in diet, water, dust

86

and air and investigate the possible external exposure doses through different

87

pathways for the general population in Beijing, China were identified. To our

88

knowledge, this is the first work to comprehensively evaluate the external exposure of

89

CPs to general populations and it can supply important data for the possible risks 5

ACS Paragon Plus Environment

Environmental Science & Technology

90

assessments, especially for MCCPs, since the relative data is very scarce.

91

Materials and Methods

92

Sample collection

93

Samples collection campaign was carried out in 2016. Drinking water (two tap

94

water and two pure water) samples were collected from our office. Duplicate diet

95

samples consisted of two parts: one part was collected from fast food outlets (n=15)

96

and the other part was collected with the help of 6 participants who provided duplicate

97

portions of what they consumed for their three meals per day (n=18). The dining

98

places of these participants mainly are two dining halls. One belongs to a university

99

servicing for approximately 20,000 people, and the other is in an institute servicing

100

for approximately 2,000 people. These two dining halls are open to the public,

101

therefore, the diet provided by the participants represented diets consumed by a large

102

group of people. The first part was used to evaluate the CPs exposure level for people

103

who eat take-away food, which is more and more popular in China. The second part

104

was used to evaluate the CPs intake levels of people who eat in the dining rooms and

105

those who eat homemade food. The food samples were freeze-dried and triturated.

106

The detailed information (food species) of the duplicate food samples is provided in

107

Tables S1 and S2. Three different brands of milk powder (n=6 samples) were

108

purchased in supermarkets.

109

Indoor air samples (n=39) and indoor dust samples (n=115) were collected in

110

residential homes, workplaces, and dormitories. Summer and winter samples were

111

both collected to study the potential seasonal differences. Passive air sampler 6

ACS Paragon Plus Environment

Page 6 of 33

Page 7 of 33

Environmental Science & Technology

112

polyurethane foam (PUF) disks were used to collect indoor air samples. Briefly, PUF

113

disks were housed in stainless steel domed chambers. Passive air samplers were

114

deployed for approximately 60 days in summer (July 2014 to September 2014) and

115

winter (December 2014 to early March 2015) at 16 sites in offices and residential

116

buildings in Beijing. Field blanks were prepared by installing pre-washed PUF disks

117

in the sampler for 5 minutes and then wrapping the PUF disks in aluminum foil and

118

placing them in zipped plastic bags until analysis. PUF disks were handled using

119

solvent-rinsed tongs. Sampling chambers were pre-cleaned and solvent-rinsed with 95%

120

ethyl alcohol prior to installation of the passive sampling media. PUF disks were

121

extracted by ASE 350 with a 1:1 (volume ratio) mixture of dichloromethane and

122

hexanes prior to use.

123

Indoor dust samples were collected using a household vacuum cleaner (D-530) by

124

placing a nylon bag over the intake nozzle of the aspirator to avoid possible

125

contaminants from the equipment. After sampling, the nylon bag was scraped off and

126

the dust was then carefully wrapped in aluminum foil. A 100-mesh sieve was

127

employed to sieve out fragments and flocs. The samples were stored in a refrigerator

128

at -20 °C until analysis.

129

Quality assurance/quality control

130

All the glassware used in this study were carefully washed with deionized water,

131

then baked in a muffle furnace at 450 °C overnight. Before use, they were rinsed three

132

times with dichloromethane. The column packings (neutral silica gel, anhydrous

133

sodium sulfate and Florisil) were all baked in a muffle furnace and rinsed with 7

ACS Paragon Plus Environment

Environmental Science & Technology

134

dichloromethane and n-hexane before purification. Each batch of 5-9 samples was

135

followed by three procedural blanks. Field blanks were prepared when indoor dust

136

and indoor air samples were collected. For indoor air field blanks, a pre-cleaned PUF

137

disk was placed in the chamber for five minutes, then scraped off and the collected

138

material was wrapped in aluminum foil. Field blanks for indoor dust were prepared by

139

sucking pre-baked anhydrous sodium sulfate with the vacuum cleaner in the same

140

manner as collecting dust samples. Field blanks showed no difference from the

141

procedural blanks. For indoor air and indoor dust samples, procedural blanks

142

contained less than 5% of the CPs content in samples. Therefore, these samples were

143

not blank-corrected. However, diet, drinking water and milk powder samples with low

144

concentrations were blank-corrected. For diet and milk powder samples, the

145

laboratory blanks contained 0.4 to 5.2 ng g-1 of SCCPs (which were equivalent to less

146

than 1% to up to 20% of SCCPs in samples), while for water samples, the procedural

147

blanks contained 42 to 48 ng L-1 of SCCPs (which were equivalent to about 30% of

148

SCCPs in water samples). MCCPs in the procedural blanks were under instrument

149

detection limit (IDL). The method detection limit (MDLs) which is defined as three

150

times the standard deviation of the procedural blanks from all of the batches. The

151

MDL of different environment matrices are provided in Table S3. The recoveries of

152

13

153

95%).

154

Daily exposure calculation

155

C10-labeled 1,5,5,6,6,10-hexachlorodecane were in the range of 53%-129% (mean:

Estimated daily intake (EDI) of SCCPs and MCCPs for the general population 8

ACS Paragon Plus Environment

Page 8 of 33

Page 9 of 33

Environmental Science & Technology

156

via diet, indoor dust, indoor air and drinking water was calculated using the following

157

equations.

EDIdiet =

Cdiet × Mdiet 1 Wt

158

EDItoddler diet =

159

EDIwater =

160

EDIair =

×  × 

%&×'%& !

&×'& !

!

2

3

4

EDIindoor dust = EDIingestion + EDIdermal adsorption 1 23 × 41 23× ∑61

1 23 × 789 × 98× 9:× ∑61 23

5

161

=

162

where Cdiet is the concentration of CPs in the diet, Mdiet is the mass of the diet sample,

163

and Wt is the weight of a person. Mmilk is the recommended milk powder daily intake

164

(Mmilk = 80 g day-1), Cmilk is the CPs concentration in milk powder, Mtoddler is the total

165

food intake of toddlers,26,27 Vwater is the volume of water ingestion (0.3 L d-1for

166

toddlers and 1.2 L d-1 for adults),28 Vair is the volume of air inhalation (8 m3 d-1 for

167

toddlers and 15.7 m3 d-1 for adults),28 Rindoor dust is the ingestion rate of indoor dust in a

168

certain kind of indoor environment (60 mg d-1 for toddlers and 30 mg d-1 for adults),28

169

Tindoor is the time spent in a certain kind of indoor environment, Wt is the weight of a

170

person, BSA is the body surface area (0.53 m2 for toddlers and 2.05 m2 for adults),28

171

AS is the soil adhered to skin (0.022 g m-2),28 and AF is the fraction of CPs adsorbed

172

in the skin (0.14).29

MOE =

!

+

!

NOAEL 6 EDI

173

Margin of exposure (MOE) is applied to evaluate the potential risks of CPs to human

174

health. MOE is the standard used by the European Food Safety Authority (EFSA) for 9

ACS Paragon Plus Environment

Environmental Science & Technology

175

chemical risks assessment. It is defined as the ratio of the no-observed-adverse-effect

176

level (NOAEL) to its estimated daily intake (EDI) amount for a person.

177

Data analysis

178

All the statistical analysis was performed using SPSS version 20.0 software.

179

One-way analysis of variance (ANOVA) was used to test statistical significance.

180

Correlation was tested applying Spearman’s rank coefficients.

181

Results

182

Levels and congener group profiles of SCCPs and MCCPs in indoor dust

183

Both ∑SCCPs and ∑MCCPs were detected in all 115 dust samples with

184

concentrations ranging from 5.35 to 1022 µg g-1 (GM = 92.0 µg g-1) and 2.10 to 725

185

µg g-1 (GM = 82.8 µg g-1), respectively (Table 1). The concentrations of MCCPs and

186

SCCPs were at comparable concentrations. However, in a German study, MCCPs

187

levels were much higher than SCCPs levels.30 The median value of SCCPs and

188

MCCPs determined in the Germany study were 6 and 176 µg g-1, while in this study

189

the corresponding value were 98.7 and 89.8 µg g-1.t in German indoor dust may

190

reflect the effective restriction of SCCPs in Europe since the 1990s,31 while in China,

191

SCCPs have not been restricted until now. ∑SCCPs + MCCPs (sum-CPs) in dust in

192

this study were 10 to 100 times higher than the results from Sweden21 and were

193

slightly lower than the concentrations in a newly opened shopping mall in China.18 In

194

addition, sum-CPs in indoor dust in Beijing were also much higher than other POPs,

195

e.g., HBCD and PBDEs, by 2-3 orders of magnitude in China.32-34 These high

196

concentrations were consistent with the high volume of industrial CP production and 10

ACS Paragon Plus Environment

Page 10 of 33

Page 11 of 33

Environmental Science & Technology

197

usage in China.

198

The relative abundance of different SCCP congener groups in indoor dust were

199

ranked in the following order: C13 (35%) > C11 (31%) > C12 (23%) > C10 (12%), while

200

different chlorine atom substitution groups were Cl7 (36%)> Cl8 (33%) > Cl9 (17%) >

201

Cl6 (9.7%) > Cl10 (3.1%) > Cl5 (0.2%) (Table 1 and Figure 1). For MCCPs, the

202

congener distribution patterns were C14 (79%) > C15 (16%) > C16 (3.7%) > C17 (1.2%)

203

and Cl8 (44%) > Cl7 (28%) > Cl9 (19%) > Cl6 (6.1%) > Cl10 (3.2%) > Cl5 (0.1%),

204

respectively (Table 2 and Figure 1). C13-CPs was the most predominant SCCPs

205

congener group in the indoor dust, which was also the most abundant in CP52

206

mixtures but with a higher proportion (Figure S2). The distribution pattern in indoor

207

dust was a result of CP52 technical mixtures shifting to lower-chain-CPs. C14 was the

208

most abundant MCCP formula group both in our results (79%) and in the results from

209

the German indoor study (60%).30 Based on the chlorine atom substitutions groups,

210

Cl7- and Cl8-CP species were the dominated species in both the composition of SCCPs

211

and MCCPs in dust, which were in agreement with the Cl7- and Cl8-CP species of

212

CP52 (72% and 62%).

213

Levels and congener profiles of SCCPs and MCCPs in indoor air

214

∑SCCPs were detected in all 39 samples in the indoor air, with a range of 9.77 -

215

966 ng m-3 (GM: 80.1 ng m-3), while ∑MCCPs were detected in 23 out of 39 samples

216

ranging from < LOD to 613 ng m-3.

217

levels in the indoor air, which implied that with lower vapor pressure, MCCPs were

218

more lipophilic and not easily volatilized into the atmosphere. The predomination of

MCCP levels were much lower than SCCP

11

ACS Paragon Plus Environment

Environmental Science & Technology

219

SCCPs in indoor environment was very different from the results in outdoor air. 33,

220

35-38

221

SCCP and MCCP levels were 5.13 and 4.21 ng m-3)35 or at even higher levels than

222

SCCPs (e.g., in the UK, SCCP and MCCP levels were 1.13 and 3.04 ng m-3,

223

respectively).33 This phenomenon implies that CPs in indoor environment and outdoor

224

environment has different sources. In addition, the atmospheric levels of total CPs in

225

the outdoor environment were lower than our results by at least one order of

226

magnitude. This outdoor dilution was consistent with our previous finding in organic

227

film on window surfaces.17 The assumption is that indoors have CPs-containing

228

consumer goods and relatively less ventilation.

MCCPs in the outdoor environment were at a comparable level (e.g., in Pakistan,

229

As a result of the higher volatility of lower-chain CPs,39 the most abundant SCCP

230

congener groups were C10 and C11 which accounted for 61% and 29%, respectively, of

231

∑ SCCPs. For MCCPs, the most abundant congener groups were C14 and C15 -CPs,

232

accounting for 55% and 34%, respectively. For different chlorine-atom congener

233

profiles of SCCPs, Cl6 and Cl7 species were the dominant groups, accounting for 48%

234

and 38% of total SCCPs. For MCCPs, the Cl5 group was notably high, constituting 41%

235

of total MCCPs. Cl6-CPs, Cl7-CPs and Cl8-CPs were evenly distributed, contributing

236

25%, 18 %, and 13%, respectively, to ∑MCCPs. The congener group profiles showed

237

similar trends among different environmental compartments except in the air (Figure

238

1c, 1d) and were consistent with the profile of CP52 products.

239 240

Levels and congener group patterns of CPs in duplicate diet samples, milk powder, and drinking water. 12

ACS Paragon Plus Environment

Page 12 of 33

Page 13 of 33

Environmental Science & Technology

241

Both ∑SCCPs and ∑MCCPs were detected in all the 33 duplicate diet samples,

242

while only SCCPs were detected at low levels in water samples. For duplicate diet

243

samples, ∑SCCP and ∑MCCP levels were in the range of 24.4-546 ng g-1 dry weight

244

(dw) (GM = 83.2 ng g-1 dw) and 17.3 to 384 ng g-1 dw (GM = 55.5 ng g-1 dw),

245

respectively. For milk powder samples, ∑SCCP and ∑MCCP levels were in the range

246

of 1.70-17.6 ng g-1 dw (GM = 18.2 ng g-1 dw) and 17 to 384 ng g-1 dw (GM = 8.87 ng

247

g-1 dw), respectively. The SCCP levels were higher than in the diet from Beijing in

248

200923 (the highest SCCP concentration of 28 ng g-1 dw). Based on the diet data,

249

Figure 4 shows the daily dietary CPs intake (calculated using Equation 1) and the

250

contribution from three meals provided by the six participants. The origins of the food

251

supplied by the participants are also provided in the supporting information (Table S2).

252

The result indicated that fried food may result in higher CPs intake levels (e.g.,

253

breakfast from V02 and V05 both contained fried food, and the CP levels were

254

higher), followed by fast food. In addition, homemade food tended to contain fewer

255

CPs (lunch from V02, lunch and supper from V06). The reason might be that

256

homemade food has different materials and cooking procedures. Hence people eating

257

fast food and eating in restaurants have a higher exposure risk of CPs via the diet

258

(Table S2, Figure S3). Larger sample sizes in further studies will be needed to exclude

259

uncertainties caused by the limited sample size in this study.

260

Congener profiles of CPs in the diet were similar to that in the indoor dust.

261

Different carbon chain length groups were relatively evenly distributed as C13 (35%) >

262

C11 (31%) > C12 (23%) > C10 (12%), while different chlorine atom substitution groups 13

ACS Paragon Plus Environment

Environmental Science & Technology

Page 14 of 33

263

Cl7 (36%) > Cl8 (33%) > Cl9 (17%) > Cl6 (9.7%) > Cl10 (3.1%) > Cl5 (0.21%) (Table 1,

264

Figure 1a, 1b). For MCCPs, C14 dominated in the diet samples, accounting for 73%.

265

Cl8-CPs were the most abundant chlorine atom congener group, while Cl7- and

266

Cl9-CPs composed 26% and 21%, respectively. No statistical correlations (for MCCP,

267

R = 0.19, P = 0.28; for SCCP, R= -0.024, P = 0.89) were found between lipid content

268

and CP content (Figure S4). ∑SCCPs in tap water ranged from 20 to 26 ng L-1, which

269

were lower than the river water levels in Japan where the concentration was 41.8 ng

270

L-1.19

271

Discussion

272

CPs differences among different microenvironments and seasons

273

CPs

in

indoor

environment

were

influenced

by

indoor

decorations

274

(microenvironments) which were related to the different building-function types.

275

SCCPs in indoor dust ranked in the following order: residential home (201 µg g-1) >

276

dormitory (113 µg g-1) > office (60µg g-1), while for MCCPs, dormitory (84 µg g-1) >

277

residential home (82 µg g-1) > office (60 µg g-1). Overall, higher levels of CPs were

278

observed in residential homes, indicating certain characteristics of this kind of

279

microenvironment (e.g., decoration and ventilation system).40

280

ANOVA was performed to analyze seasonal differences of CPs levels in indoor

281

dust, and no statistical significance was found for either SCCPs or MCCPs. Generally,

282

SCCP concentrations in winter dust samples were slightly higher than those in

283

summer (Figure 2). The summer-winter trends of SCCPs were consistent with

284

previous findings in the outdoor particles in Beijing 2011.41 The average temperature 14

ACS Paragon Plus Environment

Page 15 of 33

Environmental Science & Technology

285

at the sampling sites in wintertime was 24.5 ± 1.5 °C, while in the summer the

286

average temperature was 26.0 ± 1.5 °C. Considering that CPs belong to the

287

semi-volatile organic compounds, the experimental results indicated that higher

288

temperature might result in CPs evaporating from dust particles to the air. As shown

289

in Figure 3, CPs concentrations in indoor air during summertime were higher than the

290

CP concentrations in wintertime. This trend was the same as in our previous study41 of

291

CPs in the Beijing outdoor atmosphere. Although summer indoor air CP

292

concentrations were generally higher, no significant differences could be found

293

because a few exceptions existed (sites S01, S03, S08, and S10). In these four sites,

294

the winter CPs concentrations were at higher levels than the summer concentrations.

295

The insignificant seasonal trend indicated the potential existence of indoor sources for

296

CPs, which was consistent with the findings in the study of organic film on window

297

surfaces.17 One common characteristic of these four sites was the low window

298

frequency, which created a unique microenvironment. These exceptions suggested

299

that ventilation and heating supply differences might result in the higher airborne CP

300

concentrations (e.g., higher temperatures accelerate CPs release from CP-containing

301

consumer goods indoors).

302

Exposure dose calculation of MCCPs and SCCPs via different routes.

303

The fast food and food donated by participants were collected for different

304

purposes. We used the samples provided by six participants to reflect the true CP

305

exposure value of a person. The fast food set meals combined with body weight data

306

from national investigation results were applied to reflect the average dietary 15

ACS Paragon Plus Environment

Environmental Science & Technology

307

exposure level for the general population. For adults, diet intake was estimated using

308

24 h duplicated food samples. For toddlers (1 to 2 years old), diet intake was assumed

309

to be a combination of milk powder and adult food.26,27 The detailed calculation

310

processes are provided in the Supporting Information. The dietary exposure levels of

311

SCCPs for adults ranged from 316 to 1101 ng d-1 kg·bw-1 (GM: 611 ng d-1 kg·bw-1),

312

which was at a comparable level with results in Beijing in 2009 (GM, 620 ng d-1

313

kg·bw-1).23 The exposure levels in this study were one order of magnitude higher than

314

the exposure levels in Seoul and Tokyo (GM, 54.0 ng d-1 kg·bw-1).23 The dietary

315

exposure levels to MCCPs for adults ranged from 153 to 1307 ng d-1 kg·bw-1, and for

316

toddlers, dietary exposure levels to MCCPs ranged from 164 to 1465 ng d-1 kg·bw-1

317

(GM, 705 ng d-1 kg·bw-1). This study is also the first to report dietary exposure to

318

MCCPs for the general population in China.

319

People spend most of their time in indoor environments. For adults, we assumed

320

that they spend nine hours at the workplaces, 12.5 hours in domestic apartments, and

321

2.5 hours in other indoor environments and outdoors based on an investigation

322

conducted in the north China urban area. Toddlers were assumed to spend all their

323

time in domestic apartments. The exposure amount was calculated based on equations

324

4 and 5. To reflect the average and high ends of exposure risks of CPs, the mean and

325

95th percentile ingestion factor data adapted from the exposure factors handbook27,28

326

were applied for the calculation using equations 4 and 5. The GM of SCCPs and

327

MCCPs in indoor air and dust were used for the estimation. Toddlers and adolescents

328

have a higher inhalation rate per unit weight, and toddlers’ special behavior (higher 16

ACS Paragon Plus Environment

Page 16 of 33

Page 17 of 33

Environmental Science & Technology

329

frequency of hand-to-mouth habits) resulted in high amounts of dust ingestion.26

330

Daily inhalation exposure levels descended with age and stabilized in adulthood

331

(Figure S6). We further compared intake doses of SCCPs and MCCPs for adults and

332

1- to 2-year-old toddlers for the indoor environment, and Table 2 shows that the

333

calculated exposure level for the indoor environment for toddlers could be higher than

334

the exposure level for adults by one order of magnitude. The only available data on

335

comprehensive indoor environment exposure to CPs in the indoor environment was

336

one study from Sweden.21 In that study, the estimated median exposures to sum-CPs

337

in the indoor environment for adults and toddlers were 0.017and 0.11 µg kg-1 day-1,

338

respectively, which were much lower than the sum-CP exposure in this study (0.30

339

and 2.19 µg kg-1 day-1). A recent study investigating the CPs levels in a shopping mall

340

in northeast China found the estimated average daily exposure dose of sum-CPs for

341

adults and toddlers were 0.39 and 1.12 µg kg-1 day-1 respectively.18 The high estimated

342

indoor exposure level in China was consistent with the high volume of production and

343

usage in China in recent years.3

344

Based on the calculations above, the average daily intakes of ∑SCCPs and ∑

345

MCCPs via the four exposure pathways were estimated. The investigated daily

346

intakes for adults were 1.01 and 0.83 µg d-1 kg-1, and for toddlers were 2.31 and 1.32

347

µg d-1 kg-1, respectively. For adults, the predominant exposure pathway to SCCPs and

348

MCCPs was dietary intake, which accounted for 88% and 93% of average daily

349

intakes, respectively, followed by indoor dust exposure, which accounted for 9.3% of

350

SCCPs and 6.9% of MCCPs (Figure 5). However, for toddlers, dust ingestion was the 17

ACS Paragon Plus Environment

Environmental Science & Technology

351

most predominant exposure route and accounted for 59% of SCCPs and 51% of

352

MCCPs, followed by dietary ingestion (38% of SCCPs, 49% of MCCPs). The

353

contribution of dust ingestion and dermal permeation of dust contact to the toddlers

354

could be as high as 70% according to a study in malls in China.18 Moreover, exposure

355

differences (diet contribute highest proportion for adults’ CPs total intake while dust

356

contribute highest proportion for toddlers’ CPs intake) between adults and toddlers

357

have been observed for other POPs (e.g.: HBCD, TBBPA). 42 The combined toxic

358

effects of a variety of contaminants through dust exposure for toddlers posed potential

359

risks for this subgroup.

360

Unlike the Swedish study in which the median exposure to sum-CPs was equally

361

distributed between dust and air,21 inhalation was a less important exposure route for

362

people in this work, especially in the case of MCCPs. For SCCPs, inhalation

363

constituted 3.0% and 3.2% for adults and toddlers, respectively. Drinking water intake

364

was almost negligible compared to the other three exposure routes as the CPs are

365

highly lipophilic compounds.

366

Risk assessment through CPs exposure

367

The difference in exposure levels between adults and toddlers suggested that

368

toddlers were a highly exposed sub-group. Special attention should be paid to this

369

group when we evaluate potential risks through CPs exposure. According to the

370

European risk assessment, NOAEL of SCCPs and MCCPs were 100 mg d-1 kg-1 and

371

25 mg d-1 kg-1 respectively.1 We used the 95th percentile concentrations (to evaluate

372

potential risks and to exclude singular values) to calculate the exposure of CPs for 18

ACS Paragon Plus Environment

Page 18 of 33

Page 19 of 33

Environmental Science & Technology

373

adults and toddlers, respectively. The calculated 95th percentile intake doses of SCCPs

374

for adults and toddlers were 2.03 and 5.71 µg d-1 kg-1, respectively, which were higher

375

than the Swedish level (0.06 and 0.5 µg d-1 kg-1), The 95th percentile exposure level of

376

MCCPs for adults and toddlers were 0.95 and 1.79 µg d-1 kg-1, respectively According

377

to equation 6, the MOE values for SCCPs were 4.93× 104 and 1.75× 104, the MOE

378

values for MCCPs were 2.63× 104 and 1.39× 104. A MOE value less than 1000 (a

379

factor of ten for a research period less than one year, a factor of ten for interspecies

380

differences, and a factor of ten for individual differences) 43 is considered to pose

381

health risk potential. The calculated MOE values in this study indicated that the CPs

382

external exposure level did not posed health risks for the general population.

383

This is the first study to comprehensively evaluate different external exposure

384

pathways of SCCPs and MCCPs at the same time. We found high levels of SCCPs in

385

diet, indoor dust, indoor air, and drinking water. Since the possibly carcinogenic to

386

humans of SCCPs and the similar toxicity SCCPs and MCCPs the combined chronic

387

effects of SCCPs and MCCPs on human beings are unknown and need further efforts

388

in the future to disclose since the concentrations of CPs in environment show an

389

increasing trend in recent years.

390

ACKNOWLEDGMENTS

391

We thank the National Natural Science Foundation of China (21477141, 21625702,

392

21337002, and 21407157), the National Basic Research Program of China

393

(2015CB453102), and the Strategic Priority Research Program of the Chinese

394

Academy of Science (XDB14010400) for providing financial support. 19

ACS Paragon Plus Environment

Environmental Science & Technology

Page 20 of 33

395

References

396

(1) Fiedler H. Short-chain chlorinated paraffins: production, use and international regulations. In:

397

de Boer J, editor. Chlorinated paraffins. The handbook of environmental chemistry. Berlin,

398

Heidelberg: Springer-Verlag; 2010. p. 1-40.

399 400

(2) Muir D.C.G.; Stern G.A.; Tomy G.T.; Paasivirta (Ed.) J., 2000, In the Handbook of Environmental Chemistry, New York.

401

(3) Glüge, J.; Wang, Z.; Bogdal, C.; Scheringer, M.; Hungerbühler, K. Global production, use,

402

and emission volumes of short-chain chlorinated paraffins - A minimum scenario. Sci. Total

403

Environ. 2016, 573, 1132-1146. DOI: 10.1016/j.scitotenv.2016.08.105

404 405

(4) Tang, E.; Yao, L. Industry status of chlorinated paraffin and its development trend. China Chlor-Alkali, 2005, 2, 1-3

406

(5) Tomy, G.T.; Stern, G.N.; Lockhart, W.L.; Muir, D.C.G. Occurrence of C10−C13

407

Polychlorinated n-Alkanes in Canadian Midlatitude and Arctic Lake Sediments. Environ. Sci.

408

Technol. 1999, 33, 2858-2863 DOI: 10.1021/es990107q.

409

(6) Tomy,

G.T.;

Muir,

D.C.G.;

Stern,

G.N.;

Westmore,

J.B.

Levels

of

C10−C13

410

Polychloro-n-Alkanes in Marine Mammals from the Arctic and the St. Lawrence River

411

Estuary. Environ. Sci. Technol. 2000, 34, 1615-1619 DOI: 10.1021/es990976f

412

(7) Iozza, S.; Müller, C.E.; Schmid, P.; Bogdal, C.; Oehme, M. Historical profiles of chlorinated

413

paraffins and polychlorinated biphenyls in a dated sediment core from Lake Thun

414

(Switzerland). Environ. Sci. Technol. 2008, 42, 1045-1050 DOI: 10.1021/es702383t

415

(8) Zeng, L.; Wang, T.; Wang, P.; Liu, Q.; Han, S.; Yuan, B.; Zhu, N.; Wang, Y.; Jiang, G.

416

Distribution and Trophic Transfer of Short-Chain Chlorinated Paraffins in an Aquatic 20

ACS Paragon Plus Environment

Page 21 of 33

Environmental Science & Technology

417

Ecosystem Receiving Effluents from a Sewage Treatment Plant. Environ. Sci. Technol. 2011,

418

45, 5529-5535 DOI: 10.1021/es200895b

419 420

(9) IARC (International Agency for Research on Cancer) Summaries and evaluations. Chlorinated paraffins. 1990 Group 2B, 48, 55

421

(10) POPRC.2/14, 2006 Report of the Persistent Organic Pollutants Review Committee on the

422

work of its first meeting: Risk management evaluation on short-chain chlorinated paraffins

423

http://chm.pops.int/TheConvention/POPsReviewCommittee/POPRCRecommendations/tabid/2

424

43/ctl/Download/mid/10483/Default.aspx?id=42&ObjID=4807

425

(11) POPRC.12, 2016, Report of the Persistent Organic Pollutants Review Committee on the

426

work of its twelfth meeting: Risk management evaluation on short-chain chlorinated paraffins,

427

Rome

428

http://chm.pops.int/TheConvention/POPsReviewCommittee/Meetings/POPRC12/Overview/ta

429

bid/5171/ctl/Download/mid/16084/Default.aspx?id=31&ObjID=22595`

430

(12) UNEP/POPS/COP.8/14, 2017, Recommendation by the Persistent Organic Pollutants

431

Review Committee to list short-chain chlorinated paraffins in Annex A to the Convention and

432

draft text of the proposed amendment

433

(13) Environment Canada, 2008. Chlorinated Paraffins. Follow-up Report on a PSL1 Assessment

434

for Which Data Were Insufficient to conclude whether the Substances were “toxic” to the

435

Environment and to the Human Health. Canadian Environmental Protection Agency, Ottawa.

436

https://www.ec.gc.ca/lcpe-cepa/documents/substances/pc-cp/cps_followup-eng.pdf

437

(14) Yuan, B.; Wang, Y.; Fu, J.; Zhang, Q.; Jiang, G. An analytical method for chlorinated

438

paraffins and their determination in soil samples. Sci. Bull. 2010, 55, 2396-2402 DOI: 21

ACS Paragon Plus Environment

Environmental Science & Technology

439

Page 22 of 33

10.1007/s11434-010-3261-x.

440

(15) Wang, T.; Yu, J.; Han, S.; Wang, Y.; Jiang, G. Levels of short chain chlorinated paraffins in

441

pine needles and bark and their vegetation-air partitioning in urban areas. Environ. Pollut.

442

2015, 196, 309-312 DOI: 10.1016/j.envpol.2014.10.025.

443

(16) Zeng, L.; Li, H.; Wang, T.; Gao, Y.; Xiao, K.; Du, Y.; Wang, Y.; Jiang, G. Behavior, Fate, and

444

Mass Loading of Short Chain Chlorinated Paraffins in an Advanced Municipal Sewage

445

Treatment Plant. Environ. Sci. Technol. 2013, 47, 732-740 DOI: 10.1021/es304237m.

446

(17) Gao, W.; Wu, J.; Wang, Y.; Jiang, G. Distribution and congener profiles of short-chain

447

chlorinated paraffins in indoor/outdoor glass window surface films and their film-air

448

partitioning

449

10.1016/j.chroma.2016.04.081

in

Beijing,

China.

Chemosphere.

2016,

144,

1327-1333.

DOI:

450

(18) Shi, L.; Gao, Y.; Zhang, H.; Geng, N.; Xu, J.; Zhan, F.; Ni, Y.; Hou, X.; Chen, J.

451

Concentrations of short- and medium-chain chlorinated paraffins in indoor dusts from malls in

452

China: Implications for human exposure. Chemosphere. 2017, 172, 103-110. DOI:

453

10.1016/j.chemosphere.2016.12.150

454

(19) Iino, F.; Takasuga, T.; Senthilkumar, K.; Nakamura, N.; Nakanishi, J. Risk assessment of

455

short-chain chlorinated paraffins in Japan based on the first market basket study and species

456

sensitivity distributions. Environ. Sci. Technol. 2005, 39, 859-866 DOI: 10.1021/es049221l.

457

(20) Thomas G.O.; Farrar D.; Braekevelt, E.; Stern, G.; Kalantzi, O.I.; Martin, F.L.; Jones, K.C.

458

Short and medium chain length chlorinated paraffins in UK human milk. Environ Int. 2006,

459

32, 34-40 DOI: 10.1016/j.envint.2005.04.006.

460

(21) Fridén, UE.; McLachlan, MS.; Berger, U.; Chlorinated paraffins in indoor air and dust: 22

ACS Paragon Plus Environment

Page 23 of 33

Environmental Science & Technology

461

Concentrations, congener patterns, and human exposure. Environ Int. 2011, 37, 1169-1174.

462

DOI: 10.1016/j.envint.2011.04.002

463

(22) Cao, Y.; Harada, K.H.; Liu, W.; Yan, J.; Zhao, C.; Niisoe, T.; Adachi, A.; Fujii, Y.; Nouda, C.;

464

Takasuga, T. Short-chain chlorinated paraffins in cooking oil and related products from China.

465

Chemosphere. 2015, 138, 104-111. DOI: 10.1016/j.chemosphere.2015.05.063

466

(23) Harada K.H.; Takasuga T.; Hitomi T.; Wang, P.; Matsukami, H.; Koizumi, A. Dietary

467

exposure to short-chain chlorinated paraffins has increased in Beijing, China. Environ. Sci.

468

Technol. 2011, 45, 7019-7027. DOI: 10.1021/es200576d.

469

(24) Xia, D.; Gao, L.; Zheng, M.; Li, J.; Zhang, L.; Wu, Y.; Tian, Q.; Huang, H.; Qiao, L. Human

470

Exposure to Short- and Medium-Chain Chlorinated Paraffins via Mothers’ Milk in Chinese

471

Urban Population. Environ. Sci. Technol. 2017, 51, 608-615. DOI: 10.1021/acs.est.6b04246

472

(25) Gao, W.; Wu, J.; Wang, Y.; Jiang, G. Quantification of short- and medium-chain chlorinated

473

paraffins in environmental samples by gas chromatography quadrupole time-of-flight mass

474

spectrometry. J. Chromatogr. A, 2016, 1452, 98-106. DOI: 10.1016/j.chroma.2016.04.081

475

(26) Hogan, K; Marcus, A; Smith, R; White, P. Integrated exposure uptake biokinetic model for

476

lead in children: empirical comparisons with epidemiologic data. Environ. Health Perspect.

477

1998, 106,1557-1567.

478 479 480 481 482

(27) US EPA. Child-specific exposure factors handbook. Washington, DC, USA: US Environmental Protection Agency; 2008. EPA/600/R-06/096 F. (28) US EPA. Exposure factors handbook. . Washington, DC, USA: US Environmental Protection Agency; 2011. EPA/600/R-09/052 F. (29) Wang, Y.; Hu, J.; Lin, W.; Wang, N.; Li, C.; Luo, P.; Hashmi, M.; Wang, W.; Su, X.; Chen, C. 23

ACS Paragon Plus Environment

Environmental Science & Technology

483

Health risk assessment of migrant workers' exposure to polychlorinated biphenyls in air and

484

dust in an e-waste recycling area in China: Indication for a new wealth gap in environmental

485

rights. Environ Int. 2016, 87, 33-41. DOI: 10.1016/j.envint.2015.11.009.

486

(30) Hilger, B.; Fromme, H.; Voelkel, W.; Coelhan, M. Occurrence of chlorinated paraffins in

487

house dust samples from Bavaria, Germany. Environ. Pollut. 2012, 175, 16-21. DOI:

488

10.1016/j.envpol.2012.12.011

489 490

(31) European Parliament Council. Directive 2002/45/EC. The European Parliament and the Council of the European Union.

491

(32) Cao, Z.; Xu, F.; Li, W.; Sun, J.; Shen, M.; Su, X.; Feng, J.; Yu, G.; Covaci, A. Seasonal and

492

Particle Size-Dependent Variations of Hexabromocyclododecanes in Settled Dust:

493

Implications for Sampling. Environ. Sci. Technol. 2015, 49, 11151-11157. DOI:

494

10.1021/acs.est.5b01717

495

(33) Barber, JL; Sweetman, AJ; Thomas, GO; Braekevelt, E; Stern, GA; Jones, KC. Spatial and

496

temporal variability in air concentrations of short-chain (C-10-C-13) and medium-chain

497

(C-14-C-17) chlorinated n-alkanes measured in the UK atmosphere. Environ. Sci. Technol.

498

2005, 39, 4407-4416. DOI: 10.1021/es047949w

499

(34) Wong, F.; Suzuki, G.; Michinaka, C.; Yuan, B.; Takigami, H.; de Wit, CA.

500

Dioxin-like activities, halogenated flame retardants, organophosphate esters and chlorinatedpa

501

raffins in dust from Australia, the United Kingdom, Canada, Sweden and China. Chemosphere

502

2017, 168, 1248-1256. DOI: 10.1016/j.chemosphere.2016.10.074

503

(35) Li, Q.; Li, J.; Wang, Y.; Xu, Y.; Pan, X.; Zhang, G.; Luo, C.; Kobara, Y.; Nam, J.; Jones, K.

504

Atmospheric Short-Chain Chlorinated Paraffins in China, Japan, and South Korea. Environ. 24

ACS Paragon Plus Environment

Page 24 of 33

Page 25 of 33

Environmental Science & Technology

505

Sci. Technol. 2012, 46, 11948-11954. DOI: 10.1021/es302321n

506

(36) Wang, Y.; Li, J.; Cheng, Z.; Li, Q.; Pan, X.; Zhang, R.; Liu, D.; Luo, C.; Liu, X.;

507

Katsoyiannis, A. Short- and Medium-Chain Chlorinated Paraffins in Air and Soil of

508

Subtropical Terrestrial Environment in the Pearl River Delta, South China: Distribution,

509

Composition, Atmospheric Deposition Fluxes, and Environmental Fate. Environ. Sci. Technol.

510

2013, 47, 2679-2687. DOI: 10.1021/es304425r

511

(37) Chaemfa, C.; Xu, Y.; Li, J.; Chakraborty, P.; Syed, JH; Malik, RN; Wang, Y.; Tian, C.; Zhang,

512

G.; Jones, KC. Screening of Atmospheric Short- and Medium-Chain Chlorinated Paraffins in

513

India and Pakistan using Polyurethane Foam Based Passive Air Sampler. Environ. Sci.

514

Technol. 2014, 48, 4799-4808. DOI: 10.1021/es405186m

515

(38) Wang, X.; Zhou, J.; Lei, B.; Zhou, J.; Xu, Si.; Hu, B.; Wang, D.; Zhang, D.; Wu, M.

516

Atmospheric occurrence, homologue patterns and source apportionment of short- and

517

medium-chain chlorinated paraffins in Shanghai, China: Biomonitoring with Masson pine

518

(Pinus massoniana

519

10.1016/j.scitotenv.2016.03.240

L.)

needles.

Sci.

Total

Environ. 2016, 560,

92-100.

DOI:

520

(39) Glüge, J.; Bogdal, C.; Scheringer, M.; Buser, AM.; Hungerbühler, K. Calculation of

521

Physicochemical Properties for Short- and Medium-Chain Chlorinated Paraffins. Phys. Chem.

522

Ref. Data, 2013, 42, 2. DOI: 10.1063/1.4802693

523

(40) Cao, Z.; Xu, F.; Covaci, A.; Wu, M.; Wang, H.; Yu, G.; Wang, B.; Deng, S.; Huang, J.; Wang,

524

X. Distribution Patterns of Brominated, Chlorinated, and Phosphorus Flame Retardants with

525

Particle Size in Indoor and Outdoor Dust and Implications for Human Exposure. Environ. Sci.

526

Technol. 2014, 48, 8839-8846. DOI: 10.1021/es501224b 25

ACS Paragon Plus Environment

Environmental Science & Technology

527

(41) Wang, T.; Han, S.; Yuan, B.; Zeng, L.; Li, Y.; Wang, Y.; Jiang, G. in the atmosphere of an

528

urban setting. Environ. Pollut. 2012, 171, 38-45 DOI: 10.1016/j.envPol.2012.07.025```````

529

(42) Barghi, M.; Shin, ES.; Kim, JC.; Choi, SD.; Chang, YS. Human exposure to HBCD and

530

TBBPA via indoor dust in Korea: Estimation of external exposure and body burden. Sci. Total

531

Environ. 2017, 593, 779-786. DOI: 10.1016/j.scitotenv.2017.03.200

532

(43) Pieters, MN; Kramer, HJ; Slob, W. Evaluation of the uncertainty factor for

533

subchronic-to-chronic extrapolation: Statistical analysis of toxicity data. Regul. Toxicol.

534

Pharmacol. 1998, 27, 108-111. DOI: 10.1006/rtph.1997.119

535 536 537

538 539

Figure 1. Congener profiles of indoor dust, indoor air, duplicate diet, drinking water,

540

and CP52 products: (a) percentage of different carbon chain length groups of SCCPs, 26

ACS Paragon Plus Environment

Page 26 of 33

Page 27 of 33

Environmental Science & Technology

541

(b) percentage of different chlorine atom substitution of SCCPs, (c) percentage of

542

different carbon chain length groups of MCCPs, and (d) percentage of different

543

chlorine atom substitutions of MCCPs.

544

27

ACS Paragon Plus Environment

Environmental Science & Technology

545 546

Figure 2. Summer-winter concentrations of CPs in indoor dust in different building

547

function types (residential home, office, and dormitory are abbreviated as R (n = 14),

548

O (n = 35), and D (n = 5), respectively, in this paper), the red hollow box represents

549

summer concentration, the black striped box represents winter concentration. The

550

shadowed part represents MCCP results, and the unshaded part represents SCCP

551

results.

552

28

ACS Paragon Plus Environment

Page 28 of 33

Page 29 of 33

Environmental Science & Technology

553 554

Figure 3. Winter-summer concentrations (ng m-3) of SCCPs and MCCPs in indoor air.

555

The black bars represent winter concentrations, the red bars represent summer

556

concentrations (a) SCCPs (b) MCCPs.

557

29

ACS Paragon Plus Environment

Environmental Science & Technology

558 559

Figure 4. CP dietary intake (ng kg-1 bw d-1) calculated from 24 h duplicate food

560

samples. B represents breakfast, L stands for lunch, and S represents supper. (a)

561

SCCPs daily diet intake; (b) MCCPs daily diet intake

562

30

ACS Paragon Plus Environment

Page 30 of 33

Page 31 of 33

Environmental Science & Technology

563 564

Figure 5. Estimation of CP intake of adults and children via indoor dust, diet, indoor

565

air, and drinking water.

566

31

ACS Paragon Plus Environment

Environmental Science & Technology

Page 32 of 33

567

Table 1. SCCP and MCCP concentrations in indoor dust, indoor air, diet, milk powder,

568

and drinking water samples Mean

Geomean

Median

Min

Max

Detected

Indoor dust (µg g-1,

ΣSCCPs

148

92.0

98.7

5.35

1022

115

n=115)

ΣMCCPs

139

82.8

89.8

2.10

725

115

Indoor air (ng m-3,

ΣSCCPs

181

80.1

71.9

9.77

966

39

n=39)

ΣMCCPs

41.9

3.36

3.47

< LOD

613

23

Diet (ng g-1 dw, n=33)

ΣSCCPs

113

83.2

79.3

24.4

546

33

ΣMCCPs

82.2

55.5

40.5

17.3

384

33

Milk powder (ng g-1

ΣSCCPs

18.3

18.2

18.1

16.2

20.5

6

dw, n=6)

ΣMCCPs

14.2

8.87

17.6

1.70

23.3

6

Drinking water (ng L-1,

ΣSCCPs

23.0

22.9

23.0

20.0

26.0

4

n=4)

32

ACS Paragon Plus Environment

Page 33 of 33

Environmental Science & Technology

569

Table 2. Estimation of indoor environmental exposure of adultsa and childrena to SCCPs

570

and MCCPs via inhalation and dust exposureb. The geometric concentrations in this study

571

were used for calculation. Adults (21 to < 31 years) male -1

572

-1

Children (1 to