Impact of Clothing on Dermal Exposure to Phthalates: Observations

Mar 23, 2016 - Amandeep Saini , Clara Thaysen , Liisa Jantunen , Rachel H. McQueen , and Miriam L. Diamond. Environmental Science & Technology 2016 ...
0 downloads 0 Views 2MB Size
Subscriber access provided by University Libraries, University of Memphis

Article

Impact of clothing on dermal exposure to phthalates: observations and insights from sampling both skin and clothing Mengyan Gong, Charles J. Weschler, and Yinping Zhang Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.6b00113 • Publication Date (Web): 23 Mar 2016 Downloaded from http://pubs.acs.org on March 23, 2016

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 43

Environmental Science & Technology

1 2

Impact of clothing on dermal exposure to phthalates: observations and insights from sampling both skin and clothing

3

Mengyan Gong1,2, Charles J. Weschler1,2,3*, Yinping Zhang1,2*

4 5 6 7 8 9 10 11 12 13 14

1

Department of Building Science, Tsinghua University, Beijing, China Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing, China 3 Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey, USA 2

*

Corresponding Authors (Y.P.Z.) Address: Department of Building Science, Tsinghua University, Beijing, China; Fax: +86 10 6277 3461; Phone: +86 10 6277 2518 (O); email: [email protected] (C.J.W.) Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey, 07722; Fax: +01 732 445-0116; Phone: +01 848 445-2073; email: [email protected]

1

ACS Paragon Plus Environment

Environmental Science & Technology

15

Table of Contents Art

16

2

ACS Paragon Plus Environment

Page 2 of 43

Page 3 of 43

Environmental Science & Technology

17

Abstract

18

Clothing can either retard or accelerate dermal exposure to phthalates. To investigate the

19

impact of clothing on dermal exposure to six phthalates (DMP/DEP/DiBP/DnBP

20

/BBzP/DEHP) in real environments, two sets of experiments have been conducted: (1)

21

Skin wipes were collected from 11 adults to examine the phthalate levels on both

22

bare-skin (hand/forehead) and clothing-covered body locations (arm/back/calf); (2) Five

23

adults were asked to wear just-washed jeans for 1 day (1st experiment), 5 days (2nd

24

experiment) and 10 days (3rd experiment). Phthalates levels on their legs were measured

25

on selected days during the wearing period, and phthalate levels in the jeans were

26

measured at the end of each experiment and again after washing. Measured phthalate

27

levels on body locations covered by clothing were lower than on uncovered locations, but

28

still substantial. Dermal uptake would be underestimated by a factor of two to five if

29

absorption through body locations covered by clothing were neglected. Phthalate levels in

30

the jeans and on the legs increased with the wearing time. However, the levels in the

31

jeans and on the legs were not strongly correlated, indicating that other pathways, e.g,

32

contact with bedding or bedclothes, likely contribute to the levels on the legs. The

33

efficiency with which laundering washing removed phthalates from the jeans increased

34

with decreasing Kow; median values ranged from very low (< 5%) for DEHP to very high

35

(~ 75%) for DMP. 3

ACS Paragon Plus Environment

Environmental Science & Technology

36

Introduction

37

Phthalates have been widely used in various industrial and consumer products. Higher

38

molecular weight phthalates, such as di(2-ethylhexyl) phthalate (DEHP) and butyl benzyl

39

phthalate (BBzP), are mainly used as plasticizers in polyvinyl chloride (PVC) and other

40

polymers, while lower molecular weight phthalates, such as dimethyl phthalate (DMP)

41

and diethyl phthalate (DEP) are often used as solvents or carriers in personal care

42

products, varnishes, and coatings1, 2. Di(n-butyl) phthalate (DnBP) and di(isobutyl)

43

phthalate (DiBP) are used in both applications1, 2. The occurrence of phthalate

44

metabolites in human urine indicates that people are widely exposed to phthalates2-4.

45

Exposure to selected phthalates has been associated with adverse health effects, including

46

reproductive and developmental effects5, 6, respiratory problems7, endocrine system

47

disruption8, 9, children’s altered neurodevelopment10, 11, obesity12 and the development of

48

diabetes13. Phthalate exposure occurs through inhalation, dermal absorption and ingestion.

49

Dietary ingestion appears to be the dominant pathway for DEHP14-16, while for DMP,

50

DEP, DnBP, DiBP and BBzP, other exposure pathways appear to make significant

51

contributions 3, 17-22.

52

Compared with ingestion and inhalation exposure, dermal exposure to phthalates has

53

received little attention. This may be partially due to the use of inappropriate methods

54

(percent absorbed)23, coupled with substantial challenges in assessing dermal absorption24. 4

ACS Paragon Plus Environment

Page 4 of 43

Page 5 of 43

Environmental Science & Technology

55

To complicate matters, the resulting biologically effective dose to organs may differ for

56

different exposure pathways25. Several studies have assessed dermal exposure to

57

phthalates via contact with dust/soil and consumer products17, 18, 21, 26-29 and have found

58

that for DMP, DEP, and BBzP, dermal contact may contribute significantly to total

59

exposure. Recent studies have indicated that dermal absorption from air is also a

60

significant pathway for DEP, DiBP and DnBP17,

61

understanding regarding the impact of clothing on dermal exposure to phthalates, these

62

studies either assumed that dermal absorption on body locations covered by clothing

63

could be neglected17, 18, 21, 27-29 or assumed that clothing had no influence on dermal

64

exposure17,

65

estimated that dermal absorption contributed 3-7% of total phthalate uptake if

66

clothing-covered skin was neglected compared to 10-20% of total uptake if somewhat

67

attenuated dermal uptake occurred under clothing-covered skin. Hence, arbitrary

68

assumptions regarding the presence of phthalates on clothing-covered skin can result in

69

large uncertainties in the assessment of dermal exposure to phthalates.

20, 29-33

20, 29-33

. However, given the lack of

. Based on phthalate levels measured in hand wipes, Gong et al.19

70

Several experimental studies have examined how clothing may influence dermal

71

uptake of chemicals from air or by transfer from treated fabrics. Piotrowski et al.34 found

72

that clothing reduced dermal exposure to gas phase nitrobenzene by 20-30%, and had no

73

significant influence on dermal exposure to gas phase phenol35. Several studies found

74

permethrin uptake resulted from wearing permethrin impregnated clothing36-38. Blum et 5

ACS Paragon Plus Environment

Environmental Science & Technology

75

al.39 found that metabolites of tris(2,3-dibromopropyl) phosphate increased significantly

76

in the urine of children who wore clothing treated with this flame retardant. An in vitro

77

dermal absorption study has reported ‘every-day’’ clothing is effective at reducing

78

exposure to organophosphates40. Recently, Morrison et al.22 conducted a human exposure

79

study to examine the influence of clothing on dermal exposure to DEP and DnBP. They

80

found that, compared to bare-skinned subjects, a volunteer wearing clean clothing had 1/3

81

the uptake of DEP and 1/5 the uptake of DnBP. In contrast, when the volunteer wore

82

clothing that had been previously exposed to these phthalates, his uptake was a factor of 3

83

larger for DEP and a factor of 6.5 larger for DnBP. In other words, depending on its

84

history, clothing can either retard or accelerate dermal uptake of phthalates. In day-to-day

85

life, phthalates can sorb to clothing from the air, deposit onto clothing with airborne

86

particles, or be transferred to clothing through contact with contaminated surfaces. These

87

processes are influenced by multiple factors, including phthalate concentrations in

88

different environmental media, clothing fabric, clothing weave, efficacy of laundering,

89

storage location and time, duration of wear, how closely the clothing fits, and human

90

behavior. However, we are aware of no studies that have examined the impact of clothing

91

on dermal exposure to phthalates in real environment.

92

The aims of the present study are to: 1) measure the levels of six commonly used

93

phthalates (DMP, DEP, DiBP, DnBP, BBzP and DEHP) at naked and clothing-covered

94

body locations, 2) measure phthalate levels in clothing and examine potential correlations 6

ACS Paragon Plus Environment

Page 6 of 43

Page 7 of 43

Environmental Science & Technology

95

with levels on underlying skin, 3) examine the influence of wearing time on both

96

phthalate levels in jeans and on underlying skin, and 4) measure the fraction of phthalates

97

removed by laundering. The results are expected to increase basic understanding of the

98

impact of clothing on dermal exposure to phthalates, and to also be of use in future

99

assessment of exposure via the dermal pathway.

100

Methods

101

Two sets of experiments were conducted. All subjects were students in the

102

Department of Building Science, Tsinghua University. Fudan University’s ethical review

103

board approved the study protocol prior to collection of the skin wipe samples

104

(IRB00002408 & FWA00002399) and all the subjects gave their informed consent before

105

the experiment.

106

Phthalate levels on different body locations

107

In our previous study41, phthalate levels in skin wipes were measured on bare skin

108

locations (hand and forearm) for 10 male and 10 female adults; there were no significant

109

differences between males and females. For the present study, 11 male adults were

110

recruited. As in the previous study, all participants were asked not to use any skincare

111

products from rising in the morning until sampling in the afternoon, not to wash the skin

112

wipe locations at least four hours prior to sampling, and to try to stay in the department

113

building until sampling. The wipe procedure was similar to the process described in a US 7

ACS Paragon Plus Environment

Environmental Science & Technology

114

Environment Protection Agency (EPA) study42 and our previous studies19, 41. Briefly, a

115

pre-cleaned gauze pad (8 cm × 8 cm) was wetted with 5 ml isopropyl alcohol, and then

116

used to wipe (four successive wipes) the targeted body location. As shown in Figure 1,

117

skin wipes in the present study were taken from both bare-skin (forehead, right & left

118

back-of-hand, and right & left palm) and clothing-covered skin (right & left forearm,

119

right & left calf, and back). The sampled area of the hand was estimated by tracing its

120

outline on cross-hatched graph paper, while for other body locations a fixed area was

121

sampled by affixing flexible templates to the area sampled. The areas of the template

122

openings were 266 cm2 for the forearms, legs, and back, and 70 cm2 for the forehead.

123

Each sample was spiked with isotopically labeled recovery standards (diethyl

124

phthalate-d4 (DEP-d4), di(iso-butyl) phthalate-d4 (DiBP-d4), and di(2-ethylhexyl)

125

phthalate-d4 (DEHP-d4)) immediately after sampling. The skin wipe samples were stored

126

in a 60 mL pre-cleaned brown glass jar at -36oC until analysis. A field blank wipe was

127

prepared for each adult by soaking a pre-cleaned gauze pad in isopropyl alcohol and

128

placing it directly into a brown glass jar. Skin wipe samples were analysed for six

129

phthalates by GC/EI-MS, using methods described previously19. The samples in the

130

previous study were collected during the ‘summer’ (June, 2013 to July, 2013), while the

131

samples in present study were collected during the ‘winter’ (November, 2014). Figure 1. Sampled body locations in summer (previous study19) and winter (present

8

ACS Paragon Plus Environment

Page 8 of 43

Page 9 of 43

Environmental Science & Technology

study). ‘n’ represents the number of subjects. 132 133

Phthalate levels in clothing and on skin surfaces Since jeans are commonly worn clothing and people tend to wear them for a long

134

time between washes, they were the target clothing in these experiments. Levi 501™ 100%

135

cotton jeans (about 560g/pair) were purchased from an online retail store in China. The

136

jeans were washed together using a normal washing machine with cold tap water and

137

liquid washing detergent for about 40 min and dried naturally by hanging them on a

138

balcony. After drying about 2 cm ⅹ 2 cm pieces were cut from the washed jeans on the

139

front of the right side to determine the initial levels of phthalates in jeans before wearing,

140

and then the jeans were immediately wrapped with aluminium foil and stored at room

141

temperature until distributing them to subjects (within 3 hours). Five adults were asked to

142

wear the freshly washed jeans for 1 day (1st experiment), different freshly washed jeans

143

for 5 days (2nd experiment) and four of them wore still different freshly washed jeans for

144

10 days (3rd experiment). Skin wipes from both their right calf and right thigh were

145

collected around 5 pm on selected days during the wearing period. At the end of each

146

experiment, one approximately 4 cm ⅹ 4 cm piece was cut from the front of the right

147

thigh and another was cut from the front of the right calf for each jean to determine the

148

amount of phthalates sorbed during the wearing period. The sampling design and

149

sampling times are illustrated in Figure 2. In addition, to examine the influence of

9

ACS Paragon Plus Environment

Environmental Science & Technology

150

laundering on the phthalate levels in jeans, the jeans were washed immediately after the

151

conclusion of each experiment and dried naturally on a balcony for 15 hours; 4 cm ⅹ 4

152

cm pieces were then cut from the washed and dried jeans on the front of the right side.

153

Each piece was weighed and spiked with recovery standards (DEP-d4, DiBP-d4, and

154

DEHP-d4) immediately after sampling. The jeans samples were also stored in 60 mL

155

pre-cleaned brown glass jars at -36oC until analysis. Corresponding blank samples were

156

prepared by preparing empty brown jars. The skin wipe and jeans samples were analysed

157

using methods similar to those described in our previous study41. Figure 2. Illustration of the experimental design. Legend at bottom.

158

Data analysis

159

The average recoveries for DEP-d4, DiBP-d4 and DEHP-d4 of blanks and samples were

160

68%-103% and 74%-112% respectively. Samples with recovery rates less than 50% or

161

larger than 130% were excluded from further statistical analysis; this was less than 5% of

162

the samples. Details on the blanks are presented in the Table S1. Both the reported levels

163

in skin wipes and jeans have been adjusted by subtracting the average mass in the blank

164

and then dividing by the extraction recovery rates. Method detection limits (MDLs) were

165

calculated as three times the standard deviation of the field blanks and, when phthalates

166

were not detected in the field blanks, the laboratory instrument detection limit was used

167

as the MDL (i.e., signal-to-noise ratio of 3). All non-detected values were substituted with

10

ACS Paragon Plus Environment

Page 10 of 43

Page 11 of 43

Environmental Science & Technology

168

one-half the MDL for statistical analysis. Statistical analyses were performed using the

169

SPSS statistics software package, V. 22.0, with statistical significance defined at the p =

170

0.05 level.

171

Results and Discussion

172

Phthalate levels at bare and clothed body locations

173

Detailed information on phthalate levels on different body locations for winter samples

174

(present study) and summer samples (previous study; ref 41) are presented in Tables S2-S3

175

in the SI. DMP, DEP and BBzP are not included in Tables S2-S3 because of their low

176

detection frequency ( 0.05) between

190

the levels of DEHP on left and right forearms, left and right back-of-hands, and left and

191

right palms for either season. The levels between the left and right calf are also not

192

significantly different (only sampled in winter). In addition, the levels on the left and

193

right sides of different body locations (forearm, back of hand, palm, and calf) are

194

significantly correlated for all three compounds (see Tables S4-S6 in SI), which implies

195

that phthalate levels on the left and right side of the body were a consequence of similar

196

exposure pathways. Hence, subsequent comparisons of levels on different body locations

197

have been made based on the log-transformed average concentrations for the left and

198

right side of the body. The Paired Samples t-test indicates that the phthalate levels

199

significantly differed at different body locations, with palm > back-of-hand > forearm >

200

forehead for DEHP in summer and palm ≈ back-of-hand > forehead > forearm ≈

201

back > calf for DEHP in winter; palm > back-of-hand > forearm for DiBP and DnBP in

202

summer, and palm ≈ back-of-hand > forearm > back ≈ calf for DiBP and DnBP in

203

winter ( ‘>’ is used when p < 0.05, ‘≈’ is used when p > 0.05).

204

In both summer and winter, the levels of all three phthalates on the back-of-hand and

205

palm are significantly correlated (see Tables S4-S6 in SI). However, phthalates levels on

206

the palm are about 2 times higher than on the back-of-hand in summer, while phthalate 12

ACS Paragon Plus Environment

Page 12 of 43

Page 13 of 43

Environmental Science & Technology

207

levels on back-of-hand and palm are not significantly different in winter. Further study is

208

needed to properly interpret these observations. In summer, phthalate levels on the

209

back-of-hand and forearm are correlated, while such correlations are not observed in

210

winter. This may reflect more statistical power in summer (n = 20) than in winter (n = 11).

211

Alternately, it may reflect the fact that the forearm was clothed in winter but not in

212

summer. Hence, during the summer direct contact transfer or absorption from air occurs

213

for both the back-of-hand and forearm, while in winter this is not the case. In both

214

summer and winter, phthalate levels on the palm and forearm are not correlated, possibly

215

due to differences in the relative importance of contact transfer to the palm versus the

216

forearm. Somewhat surprisingly, given the differences in sample size, DEHP levels on

217

the forehead are correlated with levels on the back of either hand as well as on the left

218

palm in winter but not in summer. Figure 3. Box-whisker plots for phthalate levels, determined by skinwipes, on different body locations. l/rforearm, l/rcalf, l/rbhand, and l/rpalm represents left/right forearm, left/right calf, left/right back-of-hand, and left/right palm respectively.

219

Table 1 presents ratios of phthalate levels at different body locations to that on the

220

hand (palm and back-of-hand averaged). For a given body location, the ratios for DiBP

221

and DnBP are similar, and are higher than the ratios for DEHP. This latter observation

222

may reflect the fact that both direct contact transfer and indirect transfer from air

13

ACS Paragon Plus Environment

Environmental Science & Technology

223

contribute to DiBP and DnBP on the calf, forearm, back and forehead; in contrast, there

224

are kinetic constraints for DEHP transfer from air to skin30, 44 and contact transfer is

225

likely the dominant contributor to DEHP at these locations. For those locations covered

226

by clothing (calf, forearm and back), this may also be partially due to slower effective

227

diffusion of DEHP through clothing45.

228

Dermal absorption of phthalates has been estimated based on measured skin wipe

229

levels and the ratios shown in Table 1, with several assumptions (see detailed information

230

in section S1 of the SI). Figure S1 contrasts whole body dermal absorption (clothed and

231

bare skin) with dermal absorption only through bare skin. This comparison indicates that

232

dermal absorption of DiBP, DnBP and DEHP will be underestimated by a factor of two to

233

three in the summer and two to five in the winter if absorptions through body locations

234

covered by clothing are neglected. The underestimation is larger for DiBP and DnBP than

235

DEHP, reflecting the differences among the ratios shown in Table 1. These results

236

indicate the importance of including body locations covered by clothing when making

237

assessments of dermal uptake of phthalates.

238

Phthalate levels in clothing and on legs

239

The levels of DiBP, DnBP and DEHP in both the thigh and calf area of the jeans are

240

shown in Figure 4 (see Table S7 for actual values for each subject), while the levels of

241

DMP and DEP are shown in Figure S2. DEHP was the most abundant phthalate with

242

levels much larger than those for DnBP and DiBP, which in turn were larger than those 14

ACS Paragon Plus Environment

Page 14 of 43

Page 15 of 43

Environmental Science & Technology

243

for DEP and DMP. Phthalate levels in the jeans increased with wearing time. The

244

magnitude of this increase was larger for DEHP, DnBP and DiBP, the phthalates with

245

lower vapor pressures (median values of ratios between the levels in jeans at the end of

246

the 3rd and 1st experiment for DEHP, DnBP, DiBP, DEP and DMP were: thigh – 18, 4, 5, 2

247

and 2; calf – 3, 2, 2, 2 and 2). The capacity of the jeans for phthalates increases as the

248

partition coefficient between clothing and air increases. This partition coefficient

249

increases with decreasing vapor pressure and increasing Koa45. The more volatile

250

phthalates (DMP, DEP and perhaps the butyl isomers) may have approached the capacity

251

of the jeans, while the jeans can adsorb more of the less volatile phthalates, such as DEHP.

252

The levels of DMP and DEP on thigh and calf area are not significantly different.. The

253

levels of DEHP, DnBP and DiBP on the thigh area tend to be higher than those on the calf

254

area of the jeans, possibly due to greater hand-to-jean contact for the thigh area. There

255

former may also be more skin surface lipids on the thigh area, which contacts the

256

underlying skin more than the calf area; skin oil has been shown to increase the

257

partitioning between clothing and air for lipophilic SVOCs46. This should be tested in

258

future studies. The levels on the thighs of the jeans correlate with levels on the calf of the

259

jeans, as shown in Tables S8-S10 of SI, suggesting that similar pathways contribute to the

260

levels at both sites. Figure 4 Phthalate levels in jeans (µg/g) and skin wipes (µg/m2 of skin) at of the

15

ACS Paragon Plus Environment

Environmental Science & Technology

conclusion of each experiment. The symbols represent results for individual subjects (S1-S5). ‘JC/JT’ represents ‘phthalate levels in the calf/thigh area of the jeans’; ‘SC/ST’ represents ‘phthalate levels on the calf/thigh as measured with skin wipes’. 261

Using values reported in the literature45, 47for partition coefficients between cotton

262

clothing and different gas phase phthalates, coupled with reported gas phase

263

concentrations in Chinese offices and homes28, we have estimated the amount of DnBP,

264

DiBP and DEHP that one would expect to find on clothing equilibrated with its

265

environment (details of these calculations are presented in section S2 and Table S11 of the

266

SI). The resulting estimates (0.9 µg/g for DiBP, 2.0 µg/g for DnBP, and 81 µg/g for DEHP)

267

are within a factor of ten of median levels we have measured in this study for jeans that

268

had been worn until the 10th day of the 3rd experiment (for DiBP, 8.9 µg/g on calf and

269

11.2 µg/g on thigh; for DnBP 8.8 µg/g on calf and 9.6µg/g on thigh, and for DEHP 61

270

µg/g on calf and 275 µg/g on thigh). We judge the order-of-magnitude agreement between

271

estimated and measured values to be reasonable, given the variation of phthalate

272

concentrations Chinese indoor air 48 coupled with uncertainty in the partition coefficients

273

between jeans and air45, 47. The estimated time to accumulate equilibrium amounts of

274

DiBP, DnBP and DEHP in the jeans via solely gas-phase transfer is 15 days, 60 days, and

275

2100 days, respectively (Table S11). That is, transfer directly from the gas phase alone

276

cannot explain the phthalates levels measured in the jeans. Another, much faster

16

ACS Paragon Plus Environment

Page 16 of 43

Page 17 of 43

Environmental Science & Technology

277

mechanism for transferring phthalates to the jeans is contact transfer from contaminated

278

surfaces, which can occur as quickly as the time required for jeans to rub contaminants

279

from a surface. Since exposed indoor surfaces tend to be cleaned less frequently than

280

jeans are washed, there is more time for indoor surfaces to sorb phthalates from the gas

281

phase between cleanings – there is more time for the thermodynamic activity of

282

phthalates in surface films to approach those in air (see Figure 2 in ref 30). Furthermore,

283

the surfaces of phthalate plasticized materials (e.g., synthetic leather, vinyl upholstery,

284

PVC furniture), can have phthalate activities that exceed gas phase activities.

285

The levels of DiBP, DnBP and DEHP obtained from skin wipes of the thigh and

286

calf of each subject at the end of experiments 1-3 are also shown in Figure 4, while the

287

levels for all samples are shown in Figure S3. In contrast to the levels in jeans, the

288

phthalate levels on the skin of the thigh and calf were not significantly different. DEHP

289

levels on the skin increased from 1 day of wear (1st exp) to 5 days of wear (2nd exp) to 10

290

days of wear (3rd exp); DnBP on the skin increased from 1 day to 5 days of wear, and

291

then only slightly from 5 to 10 days of wear; DiBP on skin only showed an increase from

292

1 to 5 days of wear. The phthalate levels on skin wipes from the thigh correlate with

293

levels on the skin wipes from the calf, as shown in Tables S8-S10 of the SI. Phthalate

294

levels on the thigh or calf areas of the jeans do not correlate with levels from the

295

corresponding skin wipes of the thigh or calf (Tables S8-S10 of SI), except for DiBP

296

levels in “jeans-calf” with “skin-calf”, and both DiBP and DEHP levels in “jeans-calf” 17

ACS Paragon Plus Environment

Environmental Science & Technology

297

with “skin-thigh”. Although the subjects wore the jeans for approximately 12h/day (based

298

on daily activity logs), other sources such as personal care products, bedclothes and

299

bedding may contribute significantly to levels on the legs. In the present experiment, the

300

subjects slept about 8h/day (activity logs). Phthalate levels in the microenvironment of a

301

bed have been reported to be higher than concentrations in the room air49. In addition, the

302

subjects showered almost every day (sometime after the sampling), which may impact

303

phthalate levels on skin.

304

Efficiency with which laundering removes phthalates in jeans

305

For each of the five phthalates, the fraction removed from the jeans by laundering

306

(including both the washing and drying cycles) is shown in Figure S4. The levels of DMP,

307

DEP, DiBP and DnBP in the jeans decreased as a consequence of laundering, while

308

DEHP levels in some jeans actually increased. The jeans may have contacted DEHP

309

sources during washing or drying (e.g., detergent from plastic container, plastic surfaces

310

in the washing machine, plastic drying racks, the air itself). Figure 5 illustrates that the

311

efficiency with which the entire laundering process removes phthalates from the jeans

312

increases as the Kow of a given phthalate decreases. Presumably, this correlation is driven

313

by the washing cycle of the laundering process. The median values for removal efficiency

314

range from very low (< 5%) for DEHP to very high (~ 75%) for DMP, consistent with the

315

fact that phthalates with lower Kow will have larger solubilities in water. The adjusted R2

316

for the weighted linear regression (using standard error of removal efficiency as the 18

ACS Paragon Plus Environment

Page 18 of 43

Page 19 of 43

Environmental Science & Technology

317

weighing factor) between log Kow and removal efficiency is 0.70. With the exception of

318

DEHP, the removal efficiencies are not significantly different between the thigh and calf

319

regions of the jeans. Removal efficiency is influenced by many factors, including the

320

nature of the fabric, the cleaning method (e.g, temperature of water, washing time), the

321

loading of the contaminant and the drying method (e.g. drying naturally or machine

322

drying using hot-air). However, our preliminarily results indicate that for phthalates with

323

large Kow’s other measures besides machine washing with typical laundry detergents are

324

needed to reduce levels in the jeans and consequent dermal exposure. Figure 5 Correlation between Log Kow of phthalate and removal efficiency (mean±SD) due to laundering. (Values of Log Kow are taken from Table 4 in Cousins & Mackay50; these are 1.61, 2.54, 2.27, 2.26, 7.73 for DMP, DEP, DiBP, DnBP and DEHP, respectively.)

325

Limitations and future studies

326

In this first attempt to measure phthalate levels on body locations covered by

327

clothing, we found that the levels on those locations are substantial and that dermal

328

uptake from clothing covered skin cannot be neglected when considering total dermal

329

uptake of various phthalates. However, this study has several limitations, and much

330

remains to be done to more completely understand phthalate levels in wipes collected

331

from different skin surfaces – both covered and bare.

19

ACS Paragon Plus Environment

Environmental Science & Technology

332

The number of participants in both sets of experiments was relatively small, which

333

limits the statistical power for detecting differences or associations and the

334

generalizability of the present study to other populations. The relative uniformity of the

335

subjects likely helped to reduce extraneous noise and potential confounding. Nonetheless,

336

we acknowledge that p-values depend on both the magnitude of the association and the

337

sample size, and, with larger sample sizes, some of the associations may differ from those

338

reported in this paper. Furthermore, we have conducted a number of statistical tests

339

comparing the phthalate levels on different body locations, which may result in a multiple

340

comparisons problem.

341

Although phthalate levels on forehead, forearm, back, calf and hands have been

342

measured, phthalate levels on more locations, e.g. chest, thigh and feet, would increase

343

the understanding of whole body dermal exposure. It would also be valuable to measure

344

phthalate levels at the same location, both clothed and bare, under otherwise identical

345

conditions. Furthermore, the present study used one type of clothing (jeans), one type of

346

fabric (cotton) and the subjects were exposed in one campus setting; each of these

347

categories should be expanded.

348

Airborne phthalate concentrations were not measured in the present study, although

349

such measurements would have been especially valuable in the jean experiments. Future

350

studies in which phthalate levels are measured in the air (including personal air), on

351

frequently contacted indoor surfaces, in clothing and on skin would improve 20

ACS Paragon Plus Environment

Page 20 of 43

Page 21 of 43

Environmental Science & Technology

352

understanding of the sources of phthalates in jeans and on skin. Measurement of key

353

parameters, e.g. diffusion coefficients through clothing/bedding, partition coefficients

354

between clothing/bedding and air, particle deposition rates onto clothing/bedding, and

355

contact transfer rates from contaminated surfaces to both skin and clothing, would be

356

valuable. Mass transfer models are needed to predict phthalate transfer from

357

clothing/bedding to skin via direct contact or transport across air gaps between skin and

358

fabric51.

359

The impact of clothing on transdermal permeability52 warrants further study. More

360

field studies measuring the amounts of various phthalates sorbed to clothing/bedding that

361

has been stored in drawers, on shelves or hung in closets would be informative, as would

362

measurements of phthalates in clothing at the time the clothes are freshly washed and

363

after periods (days, weeks, months) of storage. Chamber studies, which compare

364

phthalate levels on the same body location with and without clothing, would allow for the

365

investigation of influencing variables under defined and controlled conditions. Human

366

behavior is also anticipated to play an important role in determining levels on skin

367

surfaces (e.g., frequency with which clothing is worn and washed, frequency with which

368

bedding is washed and changed, frequency of bathing, amount of skin covered by

369

clothing, type of clothing worn). Finally, measurements of removal efficiencies for

370

laundering and showering will aid in developing strategies to reduce levels of various

371

manmade chemicals in skin surface lipids. 21

ACS Paragon Plus Environment

Environmental Science & Technology

372

Acknowledgements

373

We thank the subjects for participating in this study, and Dr. Zhuohui Zhao for

374

presenting the study protocol to Fudan University’s ethical review board for review and

375

approval. Financial support was provided by the Natural Science Foundation of China

376

(51136002 and 51521005), Tsinghua University’s Initiative for Scientific Research

377

(20121088010) and the Special Fund of the Key Laboratory for Eco Planning & Green

378

Buildings, Ministry of Education (2013B-2).

379

Supporting Information

380

The supporting information is available free of charge via the internet at http://

381

pubs.acs.org. This information includes additional details on the phthalate levels in blank

382

samples (Table S1), phthalate levels on different body locations in summer and winter

383

(Table S2-S3), Spearman correlation coefficients between phthalate levels on different

384

body locations (Table S4-S6), dermal uptake estimation (Section S1 and Figure S1),

385

phthalate levels in jeans samples of each subject (Table S7 and Figure S2), phthalate

386

levels in skin wipes of each subject (Figure S3), Spearman correlation coefficients

387

between phthalate levels in jeans and skin (Table S8-S10), estimation of amount absorbed

388

at equilibrium and time to equilibrium (Section S2 and Table S11), removal efficiency of

389

phthalates from jeans through laundering (Figure S4).

22

ACS Paragon Plus Environment

Page 22 of 43

Page 23 of 43

Environmental Science & Technology

390

References

391

1.

392

phthalates - The human biomonitoring approach. Mol. Nutr. Food Res. 2011, 55 (1), 7-31.

393

2.

394

Findings from the National Health and Nutrition Examination Survey, 2001-2010.

395

Environ. Health Perspect. 2014, 122 (3), 235-241.

396

3. Langer, S.; Beko, G.; Weschler, C. J.; Brive, L. M.; Toftum, J.; Callesen, M.; Clausen,

397

G. Phthalate metabolites in urine samples from Danish children and correlations with

398

phthalates in dust samples from their homes and daycare centers. Int. J. Hyg. Environ.

399

Health. 2014, 217 (1), 78-87.

400

4. Guo, Y.; Alomirah, H.; Cho, H.-S.; Minh, T. B.; Mohd, M. A.; Nakata, H.; Kannan, K.

401

Occurrence of phthalate metabolites in human urine from several Asian countries.

402

Environ. Sci. Technol. 2011, 45 (7), 3138-3144.

403

5.

404

phthalate diesters in females. Crit. Rev. Toxicol. 2013, 43 (3), 200-219.

405

6.

406

phthalate diesters in males. Crit. Rev. Toxicol. 2014, 44 (6), 467-498.

407

7.

408

Calafat, A. M.; Hoepner, L. A.; Perera, F. P.; Miller, R. L. Asthma in inner-city children at

Wittassek, M.; Koch, H. M.; Angerer, J.; Bruening, T. Assessing exposure to

Zota, A. R.; Calafat, A. M.; Woodruff, T. J. Temporal trends in phthalate exposures:

Kay, V. R.; Chambers, C.; Foster, W. G. Reproductive and developmental effects of

Kay, V. R.; Bloom, M. S.; Foster, W. G. Reproductive and developmental effects of

Whyatt, R. M.; Perzanowski, M. S.; Just, A. C.; Rundle, A. G.; Donohue, K. M.;

23

ACS Paragon Plus Environment

Environmental Science & Technology

409

5-11 years of age and prenatal exposure to phthalates: The Columbia Center for

410

Children's Environmental Health Cohort. Environ. Health Perspect. 2014, 122 (10),

411

1141-1146.

412

8.

413

alter thyroid hormone levels in men. Environ. Health Perspect. 2007, 115 (7), 1029-1034.

414

9.

415

J. H.; Skakkebaek, N. E.; Andersson, A. M.; Juul, A. High urinary phthalate concentration

416

associated with delayed pubarche in girls. Int. J. Androl. 2012, 35 (3), 216-226.

417

10. Kobrosly, R. W.; Evans, S.; Miodovnik, A.; Barrett, E. S.; Thurston, S. W.; Calafat, A.

418

M.; Swan, S. H. Prenatal phthalate exposures and neurobehavioral development scores in

419

boys and girls at 6-10 years of age. Environ. Health Perspect. 2014, 122 (5), 521-528.

420

11. Whyatt, R. M.; Liu, X. H.; Rauh, V. A.; Calafat, A. M.; Just, A. C.; Hoepner, L.; Diaz,

421

D.; Quinn, J.; Adibi, J.; Perera, F. P.; Factor-Litvak, P. Maternal prenatal urinary phthalate

422

metabolite concentrations and child mental, psychomotor, and behavioral development at

423

3 years of age. Environ. Health Perspect. 2012, 120 (2), 290-295.

424

12. Zhang, Y. H.; Meng, X. Z.; Chen, L.; Li, D.; Zhao, L. F.; Zhao, Y.; Li, L. X.; Shi, H. J.

425

Age and sex-specific relationships between phthalate exposures and obesity in Chinese

426

children at puberty. PLoS One 2014, 9 (8), e104852.

427

13. Sun, Q.; Cornelis, M. C.; Townsend, M. K.; Tobias, D. K.; Eliassen, A. H.; Franke, A.

428

A.; Hauser, R.; Hu, F. B. Association of urinary concentrations of bisphenol A and

Meeker, J. D.; Calafat, A. M.; Hauser, R. Di(2-ethylhexyl) phthalate metabolites may

Frederiksen, H.; Sorensen, K.; Mouritsen, A.; Aksglaede, L.; Hagen, C. P.; Petersen,

24

ACS Paragon Plus Environment

Page 24 of 43

Page 25 of 43

Environmental Science & Technology

429

phthalate metabolites with risk of type 2 diabetes: A prospective investigation in the

430

Nurses' Health Study (NHS) and NHSII Cohorts. Environ. Health Perspect. 2014, 122 (6),

431

616-623.

432

14. Rudel, R. A.; Gray, J. M.; Engel, C. L.; Rawsthorne, T. W.; Dodson, R. E.; Ackerman,

433

J. M.; Rizzo, J.; Nudelman, J. L.; Brody, J. G. Food packaging and bisphenol A and bis

434

(2-ethyhexyl) phthalate exposure: Findings from a dietary intervention. Environ. Health

435

Perspect. 2011, 119 (7), 914-920.

436

15. Koch, H. M.; Lorber, M.; Christensen, K. L. Y.; Palmke, C.; Koslitz, S.; Bruning, T.

437

Identifying sources of phthalate exposure with human biomonitoring: Results of a 48 h

438

fasting study with urine collection and personal activity patterns. Int. J. Hyg. Environ.

439

Health. 2013, 216 (6), 672-681.

440

16. Fromme, H.; Gruber, L.; Schlurnmer, M.; Wz, G.; Boehmer, S.; Angerer, J.; Mayer,

441

R.; Liebl, B.; Bolte, G. Intake of phthalates and di(2-ethylhexyl)adipate: results of the

442

integrated exposure assessment survey based on duplicate diet samples and

443

biomonitoring data. Environ. Int. 2007, 33 (8), 1012-1020.

444

17. Bekö, G.; Weschler, C. J.; Langer, S.; Callesen, M.; Toftum, J.; Clausen, G.

445

Children's phthalate intakes and resultant cumulative exposures estimated from urine

446

compared with estimates from dust ingestion, inhalation and dermal absorption in their

447

homes and daycare centers. PLoS One 2013, 8 (4), e62442.

448

18. Gaspar, F. W.; Castorina, R.; Maddalena, R. L.; Nishioka, M. G.; McKone, T. E.; 25

ACS Paragon Plus Environment

Environmental Science & Technology

449

Bradman, A. Phthalate exposure and risk assessment in California child care facilities.

450

Environ. Sci. Technol. 2014, 48 (13), 7593-7601.

451

19. Gong, M. Y.; Weschler, C. J.; Liu, L. P.; Shen, H. Q.; Huang, L. H.; Sundell, J.;

452

Zhang, Y. P. Phthalate metabolites in urine samples from Beijing children and

453

correlations with phthalate levels in their handwipes. Indoor Air 2015, 25 (6), 572-581.

454

20. Weschler, C. J.; Bekö, G.; Koch, H. M.; Salthammer, T.; Schripp, T.; Toftum, J.;

455

Clausen, G. Transdermal uptake of diethyl Phthalate and di (n-butyl) phthalate directly

456

from Air: Experimental verification. Environ. Health Perspect. 2015, 123 (10), 928-934.

457

21. Wormuth, M.; Scheringer, M.; Vollenweider, M.; Hungerbuhler, K. What are the

458

sources of exposure to eight frequently used phthalic acid esters in Europeans? Risk Anal.

459

2006, 26 (3), 803-824.

460

22. Morrison, G. C.; Weschler, C. J.; Bekö, G.; Koch, H. M.; Salthammer, T.; Schripp, T.;

461

Toftum, J.; Clausen, G. Role of clothing in both accelerating and impeding dermal

462

absorption of airborne SVOCs. J. Expo. Sci. Environ. Epidemiol. 2016, 26 (1), 113-118.

463

23. Kissel, J. C. The mismeasure of dermal absorption. J. Expo. Sci. Environ. Epidemiol.

464

2011, 21 (3), 302-309.

465

24. Ott, W. R.; Steinemann, A. C.; Wallace, L. A. Exposure analysis; CRC Press: Boca

466

Raton, U.S., 2006.

467

25. Mielke, H.; Partosch, F.; Gundert-Remy, U. The contribution of dermal exposure to

468

the internal exposure of bisphenol A in man. Toxicol. Lett. 2011, 204 (2), 190-198. 26

ACS Paragon Plus Environment

Page 26 of 43

Page 27 of 43

Environmental Science & Technology

469

26. Kim, H.-H.; Yang, J.-Y.; Kim, S.-D.; Yang, S.-H.; Lee, C.-S.; Shin, D.-C.; Lim, Y.-W.

470

Health risks assessment in children for phthalate exposure associated with childcare

471

facilities and indoor playgrounds. Environ. Health Toxicol. 2011, 26, e2011008.

472

27. Guo, Y.; Kannan, K. Comparative assessment of human exposure to phthalate esters

473

from house dust in China and the United States. Environ. Sci. Technol. 2011, 45 (8),

474

3788-3794.

475

28. Wang, X. K.; Tao, W.; Xu, Y.; Feng, J. T.; Wang, F. H. Indoor phthalate concentration

476

and exposure in residential and office buildings in Xi’an, China. Atmos. Environ. 2014,

477

87, 146-152.

478

29. Ji, Y. Q.; Wang, F. M.; Zhang, L. B.; Shan, C. Y.; Bai, Z. P.; Sun, Z. R.; Liu, L. L.;

479

Shen, B. X. A comprehensive assessment of human exposure to phthalates from

480

environmental media and food in Tianjin, China. J. Hazard. Mater. 2014, 279, 133-140.

481

30. Weschler, C. J.; Nazaroff, W. W. SVOC exposure indoors: Fresh look at dermal

482

pathways. Indoor Air 2012, 22 (5), 356-377.

483

31. Little, J. C.; Weschler, C. J.; Nazaroff, W. W.; Liu, Z.; Hubal, E. A. C. Rapid methods

484

to estimate potential exposure to semivolatile organic compounds in the indoor

485

environment. Environ. Sci. Technol. 2012, 46 (20), 11171-11178.

486

32. Gong, M. Y.; Zhang, Y. P.; Weschler, C. J. Predicting dermal absorption of gas‐

487

phase chemicals: transient model development, evaluation, and application. Indoor Air

488

2014, 24 (3), 292-306. 27

ACS Paragon Plus Environment

Environmental Science & Technology

489

33. Weschler, C. J.; Nazaroff, W. W. Dermal uptake of organic vapors commonly found

490

in indoor air. Environ. Sci. Technol. 2014, 48 (2), 1230-1237.

491

34. Piotrowski, J. Further investigations on the evaluation of exposure to nitrobenzene.

492

Br. J. Ind. Med. 1967, 24 (1), 60.

493

35. Piotrowski, J. Evaluation of exposure to phenol: absorption of phenol vapour in the

494

lungs and through the skin and excretion of phenol in urine. Br. Med. J. 1971, 28 (2), 172.

495

36. Appel, K. E.; Gundert-Remy, U.; Fischer, H.; Faulde, M.; Mross, K. G.; Letzel, S.;

496

Rossbach, B. Risk assessment of Bundeswehr (German Federal Armed Forces)

497

permethrin-impregnated battle dress uniforms (BDU). Int. J. Hyg. Environ. Health. 2008,

498

211 (1), 88-104.

499

37. Rossbach, B.; Appel, K. E.; Mross, K. G.; Letzel, S. Uptake of permethrin from

500

impregnated clothing. Toxicol. Lett. 2010, 192 (1), 50-55.

501

38. Kegel, P.; Letzel, S.; Rossbach, B. Biomonitoring in wearers of permethrin

502

impregnated battle dress uniforms in Afghanistan and Germany. Occup. Environ. Med.

503

2014, 71 (2), 112-117.

504

39. Blum, A.; Gold, M. D.; Ames, B. N.; Jones, F. R.; Hett, E. A.; Dougherty, R. C.;

505

Horning, E. C.; Dzidic, I.; Carroll, D. I.; Stillwell, R. N. Children absorb tris-BP flame

506

retardant from sleepwear: urine contains the mutagenic metabolite, 2, 3-dibromopropanol.

507

Science 1978, 201 (4360), 1020-1023.

508

40. Moore, C.; Wilkinson, S.; Blain, P.; Dunn, M.; Aust, G.; Williams, F. Use of a human 28

ACS Paragon Plus Environment

Page 28 of 43

Page 29 of 43

Environmental Science & Technology

509

skin in vitro model to investigate the influence of ‘every-day’clothing and skin surface

510

decontamination on the percutaneous penetration of organophosphates. Toxicol. Lett.

511

2014, 229 (1), 257-264.

512

41. Gong, M. Y.; Zhang, Y. P.; Weschler, C. J. Measurement of phthalates in skin wipes:

513

Estimating exposure from dermal absorption. Environ. Sci. Technol. 2014, 48 (13),

514

7428-7435.

515

42. Morgan, M. K.; Sheldon, L. S.; Croghan; C.W.; Chuang, J. C.; Lordo, R. A.; Wilson,

516

N. K.; Lyu, C.; Brinkman, M.; Morse, N.; Chou, Y. L.; Hamilton, C.; Finegold, J. K.;

517

Hand, K.; Gordon, S. M. A pilot study of children's total exposure to persistent pesticides

518

and other persistent organic pollutants (CTEPP), EPA/600/R-041-193, US EPA National

519

Exposure Research Laboratory, Research Triangle Park, NC. 2004.

520

43. Chen, L.; Zhao, Y.; Li, L. X.; Chen, B. H.; Zhang, Y. H. Exposure assessment of

521

phthalates in non-occupational populations in China. Sci. Total Environ. 2012, 427,

522

60-69.

523

44. Weschler, C. J.; Nazaroff, W. W. Semivolatile organic compounds in indoor

524

environments. Atmos. Environ. 2008, 42 (40), 9018-9040.

525

45. Cao, J. P.; Weschler, C. J.; Luo, J. J.; Zhang, Y. P. Cm-history method, a novel

526

approach to simultaneously measure source and sink parameters important for estimating

527

indoor exposures to SVOCs. Environ. Sci. Technol. 2016, 50 (2), 825-834.

29

ACS Paragon Plus Environment

Environmental Science & Technology

528

46. Morrison, G.; Shakila, N.; Parker, K. Accumulation of gas‐phase methamphetamine

529

on clothing, toy fabrics, and skin oil. Indoor Air 2014, 25 (4), 405-414.

530

47. Morrison, G.; Li, H.; Mishra, S.; Buechlein, M. Airborne phthalate partitioning to

531

cotton clothing. Atmos. Environ. 2015, 115, 149-152.

532

48. Cao, Y.; Liu, J. G.; Liu, Y.; Wang, J.; Hao, X. W. An integrated exposure assessment

533

of phthalates for the general population in China based on both exposure scenario and

534

biomonitoring estimation approaches. Regul Toxicol Pharm 2016, 74, 34-41.

535

49. Liang, Y. R.; Xu, Y. Emission of phthalates and phthalate alternatives from vinyl

536

flooring and crib mattress covers: The influence of temperature. Environ. Sci. Technol.

537

2014, 48 (24), 14228-14237.

538

50. Cousins, I.; Mackay, D. Correlating the physical–chemical properties of phthalate

539

esters using thethree solubility'approach. Chemosphere 2000, 41 (9), 1389-1399.

540

51. Morrison, G. C.; Weschler, C. J.; Bekö, G. Dermal uptake directly from air under

541

transient conditions: Advances in modeling and comparisons with experimental results

542

for human subjects. Indoor Air 2016, online avaliable, doi: 10.1111/ina.12277.

543

52. Brouwer, D.; De Vreede, J.; Meuling, W.; Van Hemmen, J.; Honeycutt, H.

544

Determination of the efficiency for pesticide exposure reduction with protective clothing:

545

a field study using biological monitoring. In Worker Exposure to Agrochemicals:

546

Methods for Monitoring and Assessment; Honeycutt

547

press: 2000; 63-84.

R. C.

30

ACS Paragon Plus Environment

and Day E. W., Eds.; CRC

Page 30 of 43

Page 31 of 43

Environmental Science & Technology

548

Figure Captions

549

Figure 1. Sampled body locations in summer (previous study19) and winter (present

550

study). ‘n’ represents the number of subjects.

551

Figure 2. Illustration of the experimental design. Legend at bottom.

552

Figure 3. Box-whisker plots for phthalate levels, determined by skinwipes, on different

553

body locations. l/rforearm, l/rcalf, l/rbhand, and l/rpalm represents left/right forearm,

554

left/right calf, left/right back-of-hand, and left/right palm respectively.

555

Figure 4 Phthalate levels in jeans (µg/g) and skin wipes (µg/m2 of skin) at of the

556

conclusion of each experiment. The symbols represent results for individual subjects

557

(S1-S5). ‘JC/JT’ represents ‘phthalate levels in the calf/thigh area of the jeans’; ‘SC/ST’

558

represents ‘phthalate levels on the calf/thigh as measured with skin wipes’.

559

Figure 5 Correlation between Log Kow of phthalate and removal efficiency (mean±SD)

560

due to laundering. (Values of Log Kow are taken from Table 4 in Cousins & Mackay50;

561

these are 1.61, 2.54, 2.27, 2.26, 7.73 for DMP, DEP, DiBP, DnBP and DEHP,

562

respectively.)

31

ACS Paragon Plus Environment

Environmental Science & Technology

563

Figure 1

564

32

ACS Paragon Plus Environment

Page 32 of 43

Page 33 of 43

565

Environmental Science & Technology

Figure 2

566

33

ACS Paragon Plus Environment

Environmental Science & Technology

567

Figure 3

568

34

ACS Paragon Plus Environment

Page 34 of 43

Page 35 of 43

569

Environmental Science & Technology

Figure 4

570

35

ACS Paragon Plus Environment

Environmental Science & Technology

571

Figure 5

572

36

ACS Paragon Plus Environment

Page 36 of 43

Page 37 of 43

573 574 575

Environmental Science & Technology

Table 1. Geometric means (95% CIa) for the ratios of phthalate levels at different body locations to that on the hand

DEHP

DiBP

DnBP

calf/hand

forearm/hand

back/hand

forehead/hand

Summer

b

0.32(0.22-0.45)

b

0.23(0.15-0.35)

Winter

0.17(0.10-0.29)

0.27(0.17-0.43)

0.24(0.15-0.39)

0.49(0.31-0.75)

Summer

b

0.44(0.27-0.74)

b

c

Winter

0.23(0.11-0.47)

0.48(0.27-0.86)

0.61(0.35-1.06)

c

Summer

b

0.38(0.23-0.61)

b

c

Winter

0.27(0.18-0.42)

0.48(0.34-0.69)

0.57(0.42-0.78)

c

Ratios were calculated for each subject and then the geometric means were calculated. a: The 95% confidence interval was back-calculated from the log-transformed data. b: The phthalate levels on the calf were not measured in summer. c: Ratios that include DiBP and DnBP on the forehead are not reported due to their low detection frequency (< 30%) at this location.

576

37

ACS Paragon Plus Environment

Environmental Science & Technology

TOC Art 84x47mm (300 x 300 DPI)

ACS Paragon Plus Environment

Page 38 of 43

Page 39 of 43

Environmental Science & Technology

Figure 1. Sampled body locations in summer (previous study19) and winter (present study). ‘n’ represents the number of subjects. 68x47mm (300 x 300 DPI)

ACS Paragon Plus Environment

Environmental Science & Technology

Figure 2. Illustration of the experimental design. Legend at bottom. 84x47mm (300 x 300 DPI)

ACS Paragon Plus Environment

Page 40 of 43

Page 41 of 43

Environmental Science & Technology

Figure 3. Box-whisker plots for phthalate levels, determined by skinwipes, on different body locations. l/rforearm, l/rcalf, l/rbhand, and l/rpalm represents left/right forearm, left/right calf, left/right back-of-hand, and left/right palm respectively. 84x170mm (300 x 300 DPI)

ACS Paragon Plus Environment

Environmental Science & Technology

Figure 4 Phthalate levels in jeans (µg/g) and skin wipes (µg/m2 of skin) at of the conclusion of each experiment. The symbols represent results for individual subjects (S1-S5). ‘JC/JT’ represents ‘phthalate levels in the calf/thigh area of the jeans’; ‘SC/ST’ represents ‘phthalate levels on the calf/thigh as measured with skin wipes’. 84x194mm (300 x 300 DPI)

ACS Paragon Plus Environment

Page 42 of 43

Page 43 of 43

Environmental Science & Technology

Figure 5 Correlation between Log Kow of phthalate and removal efficiency (mean±SD) due to laundering. (Values of Log Kow are taken from Table 4 in Cousins & Mackay50; these are 1.61, 2.54, 2.27, 2.26, 7.73 for DMP, DEP, DiBP, DnBP and DEHP, respectively.) 84x69mm (300 x 300 DPI)

ACS Paragon Plus Environment