Isomer-Specific Transplacental Transfer of Perfluoroalkyl Acids

Apr 24, 2017 - For PFOS isomers, the concentration ratios between cord serum and maternal serum (RCM) were ordered n < iso < 4m < (3 + 5)m < 1m < ∑m...
0 downloads 10 Views 574KB Size
Subscriber access provided by HACETTEPE UNIVERSITESI KUTUPHANESI

Article

Isomer-Specific Transplacental Transfer of Perfluoroalkyl Acids: Results from a Survey of Paired Maternal, Cord Sera and Placentas Fangfang Chen, Shanshan Yin, Barry C. Kelly, and Weiping Liu Environ. Sci. Technol., Just Accepted Manuscript • Publication Date (Web): 24 Apr 2017 Downloaded from http://pubs.acs.org on April 25, 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 26

Environmental Science & Technology

1

Isomer-Specific Transplacental Transfer of Perfluoroalkyl Acids: Results from a Survey of

2

Paired Maternal, Cord Sera and Placentas

3

Fangfang Chen1, Shanshan Yin1, Barry C. Kelly2*, Weiping Liu1*

4

1

Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health,

5

College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058,

6

China

7 8

2

Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore

9

Corresponding author. * Department of Civil and Environmental Engineering, National University

10

of Singapore, Block E1A, #07-03, No.1 Engineering Drive 2, Singapore 117576. Tel. (+65-6516

11

3764); Fax (+65-6779-1635); Email: [email protected]

12

* College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China 310058.

13

Tel. (+86-571- 8898 2341); Fax (+86-571- 8898 2341); Email: [email protected]

14

1 ACS Paragon Plus Environment

Environmental Science & Technology

15

Graphical Abstract for TOC

16

2 ACS Paragon Plus Environment

Page 2 of 26

Page 3 of 26

Environmental Science & Technology

17

ABSTRACT

18

Currently, information regarding isomer-specific concentrations of PFHxS, PFOS, and PFOA in

19

human placenta, and corresponding placental-maternal ratios (RPM) of these compounds does not

20

exist. The objective of the present study was to assess the occurrence, and distribution of

21

different PFHxS, PFOS and PFOA isomers in maternal serum, umbilical cord serum and

22

placenta to gain a better understanding of transplacental transport efficiency and prenatal

23

exposure risks. The study involved quantitative determination of isomer-specific concentrations

24

of PFHxS, PFOS and PFOA in samples of maternal serum (n = 32), cord serum (n = 32) and

25

placenta (n = 32) from pregnant women in Wuhan, China. The results indicate that both linear

26

and branched PFHxS, PFOS and PFOA can be efficiently transported across the placenta, with

27

exposure levels ordered maternal serum > cord serum > placenta. For PFOS isomers, the

28

concentration ratios between cord serum and maternal serum (RCM) were ordered n < iso < 4m


176

PFHxS, which is consistent with previous studies.14, 29-31 Concentrations of PFAAs in subjects

177

from the present study (Wuhan, China) were consistently lower than those previously reported in

178

subjects living in northern China, including cities such as Shijiazhuang, Tianjin, and Handan.5, 14,

179

29

180

those in other countries.27, 32, 33 The relatively high concentrations of PFAAs in northern China, is

181

likely due to continued production of textiles utilizing PFOS. Concentrations of these studied

182

PFAAs were ordered maternal sera > cord sera > placentas, (p < 0.05). In the observation of

183

higher concentrations of PFAAs in maternal sera compared to cord sera is consistent with

184

previous reports of PFOS and PFOA.6, 23, 27, 34 However, these findings contradicts with the

185

findings by Zhang et al., which found that PFHxS and PFOS were with the concentration

186

followed maternal sera > placentas > cord sera.35 It may be due to the following reasons, (i) the

187

concentrations of total PFHxS and PFOS in placentas and cord sera were close in both this study

188

and Zhang’s study. In addition, the range of concentration in the placentas in Zhang’s study was

189

wider than that in this study, and (ii) the samples in these two studies were from the different city

190

of China (Wuhan and Tianjin). Therefore their different linear and branched compositions may

191

lead to different distribution in placentas and cord sera due to different transplacental transfer

However, concentrations of PFAAs in subjects from the present study are still higher than

10 ACS Paragon Plus Environment

Page 10 of 26

Page 11 of 26

Environmental Science & Technology

192

efficiencies. Given all that, the rank order of total PFHxS and PFOS in placentas and cord sera in

193

this study may differ from that in Zhang’s study.

194

Table S5 of the SI shows the isomer-specific PFHxS, PFOS and PFOA concentrations in

195

matched maternal sera, cord sera and placentas. Linear and branched PFHxS and PFOS were

196

detected in all of the maternal sera, cord sera, and placentas. Branched PFOA was detected less

197

frequently in maternal sera, cord sera and placentas, with detection frequencies of 0% for 5m-,

198

4m- and tb-PFOA. Branched PFOS isomers contributed approximately 17% (median) of total

199

PFOS in maternal sera, 24% in cord sera and 29% in placentas (Figure 2). The proportion of

200

linear PFOS in human sera of previous studies was generally lower than that in historical ECF

201

PFOS standards (i.e 70%), such as Sweden (68.1%), Australia (58.7%), Norway (57%–70%),

202

Canada (64%), and China (48.1%).6, 15, 29, 36 While our result with the proportion of n-PFOS

203

(83%) was not consistent with these studies. One previous study conducted in Vietnam similarly

204

reported a relatively high n-PFOS contribution (83%).37 The reason for these differences is not

205

clear. The exposure source, metabolism of its precursors (PreFOS), or pharmacokinetics in the

206

human body may contribute to the observed differences. It has been reported that linear PFOS

207

and PFOA are more bioaccumulative and exhibit lower urinary excretion rates compared to

208

branched PFOS and PFOA.12, 14, 15 Branched PFOA isomers contributed 9% (median) of total

209

PFOA in maternal sera, 11% in cord sera and 8% in placentas. The proportion of linear PFOA

210

was significantly higher than in historical ECF PFOA (78%), which is consistent with previous

211

studies.6, 15, 29, 36 The branched compositions of total PFOS and PFOA were consistently and

212

significantly (p < 0.001) lower in maternal sera than in corresponding cord sera (Figure 2), which

213

is consistent with previous studies.6, 23 This indicates branched isomers of PFOS and PFOA were

214

transported more efficiently than their linear isomers. Branched PFHxS isomers contributed 14% 11 ACS Paragon Plus Environment

Environmental Science & Technology

215

(median) of total PFHxS in maternal sera, 3% in cord sera and 23% in placentas indicating lower

216

transplacental efficiency of branched PFHxS compared to linear PFHxS. The reason for higher

217

transplacental efficiency of branched PFHxS is unclear, which requires further investigation.

218

Placental transfer. The occurrence of linear and branched PFAA residues in cord serum and

219

placenta indicates that these chemicals can be transported through the placenta into the umbilical

220

cord blood, with retention in the placenta. Previous studies have demonstrated that shorter-chain

221

perfluoroalkyl sulfonic acids (PFSAs) cross the placenta more efficiently than longer-chain

222

PFSAs.20, 26, 27 For example, these previous studies reported RCM values of total PFHxS (C6) was

223

greater than that of total PFOS (C8), which is consistent with our findings. Specifically, Figure 3

224

shows RCM values were consistently higher than RPM for total PFHxS, PFOS, and PFOA in the

225

present study.

226

The median RCM (0.392-0.963, Table S6 of the SI) of different branched PFOS isomers

227

were greater than those of linear isomer (0.370), indicating that all the branched isomers of

228

PFOS were transferred more efficiently than the linear isomer (Figure 4-A). In particular, RCM

229

values decreased as the branching point moved away from the sulfonate moiety among the

230

perfluoromethyl PFOS branched isomers: iso < 4m < (3+5)m < 1m. This is similar to the

231

structure–activity relationship reported by Beesoon et al. (2011).6 In the present study, the RCM of

232

Σm2-PFOS was still higher than 1m-PFOS, which is different with the result of Beesoon et al.

233

(2011).6 However, similar to results of Beesoon et al. (2011),6 1m-, (3+5)m-, 4m-, and

234

particularly Σm2-PFOS, the concentrations in cord sera were sometimes higher than in maternal

235

sera (i.e. RCM values > 1.0). For RPM, a similar trend was observed for branched PFOS isomers:

236

iso < 4m ≈ (3+5)m < 1m (Figure 4-B), which has not been observed previously. No obvious

237

structure-activity relationship of RCM and RPM was observed for PFOA isomers (Figure 4), 12 ACS Paragon Plus Environment

Page 12 of 26

Page 13 of 26

Environmental Science & Technology

238

consistent with results of Beesoon et al. (2011).6 RCM and RPM of n-PFHxS were greater than

239

those of br-PFHxS (Figure 4). Sometimes, the RPM is slightly different with the RCM for above

240

compounds. The variation of physiology and pathology of individual placenta might have

241

contributed to the placental differences.38 For example, the difference in the fat weight, the size

242

of the placenta,39 or inflammation during the delivery was reported to be an important factor of

243

the transplacental transport.40

244

It has been reported that passive diffusion often governs transport mechanism for drugs

245

crossing the placental barrier.41 Generally, more hydrophobic compounds exhibit higher

246

placental transfer efficiency compared to more hydrophilic compounds.42 However, branched

247

isomers of PFHxS, PFOS and PFOA are less hydrophobic than their linear isomers, based on

248

their elution orders in reversed-phase chromatography. Further, Sastry claimed that compounds

249

with a more “rounded” molecular shape may have lower transplacental efficiency due to steric

250

effects.43 Therefore, branched isomers of PFHxS, PFOS and PFOA are anticipated to have lower

251

transplacental efficiencies compared to linear isomers based on passive diffusion. However, the

252

findings from the present study show that only PFHxS followed this notion. Transport of

253

chemicals across placenta can also be influenced by the degree of binding to plasma protein.6, 44

254

Beesoon et al. (2015) reported that binding affinity of linear PFOS and PFOA to human serum

255

albumin were much stronger than branched isomers,45 which may explain the higher

256

transplacental efficiency of the branched isomers of PFOS and compared to linear isomers.

257

Moreover, according to Beesoon et al. (2015), the rank order of protein binding affinities for the

258

different PFOS isomers was 3m- < 4m- < 1m- < 5m- < iso- < n-PFOS.45 The findings in the

259

present study are generally consistent with this rank order, with the exception of 1m-PFOS. The

13 ACS Paragon Plus Environment

Environmental Science & Technology

260

fact that binding affinity of n-PFOS was much stronger than n-PFOA may explain the reason

261

RCM of n-PFOA was greater than that of n-PFOS in the present study (Figure 4).45

262

In addition to passive diffusion, active transport may also play an important role in placental

263

transport. In human placenta, multiple transporter proteins are expressed on both sides of the

264

placental cells, which may elicit advective chemical transport across the placenta.46 These

265

transporters are capable of either increasing or decreasing the chemical concentration in placental

266

cells, given the characteristic and location of these transporters and the specificity of their

267

substrates.47, 48 Organic anion transporter (OAT) proteins were identified as the principal

268

transporter of PFOS located on the basal side (the fetal-facing basolateral membrane) of the

269

placenta.36, 37 Kummu et al. have reported that the expressions of OAT4 in the placenta were

270

negatively correlated with transplacental efficiencies of PFOS and PFOA, indicating these active

271

transporter proteins may ultimately lower prenatal exposure to these compounds.49 Further, Pan

272

et al. (2017) have observed lower transfer efficiency of PFAAs with higher glomerular filtration

273

rate (GFR).50 GFR is the clearance rate when any solute is freely filtered and is neither

274

reabsorbed nor secreted by the kidneys.51 GFR was also suggested to be associated with the

275

transfer efficiency of the PFAAs.52 Specifically, the OAT 4 expressed on both sides of the

276

kidney, OAT4 could either take up organic anions from the primary urine (“influx mode”) or

277

release organic anions from the cell into the tubule lumen (“efflux mode”) depends on its

278

different location expressed in the kidney.53 Further studies of advective transport mechanism via

279

specific transporter proteins in the placenta or kidney are warranted, as they may help to better

280

understand placental transport mechanism of these and other organic contaminants.

281

Mother-Placenta-fetus Distribution. Significant correlations were observed between linear and

282

branched PFAA concentrations in maternal serum, cord serum, and placenta samples (r > 0.7, p 14 ACS Paragon Plus Environment

Page 14 of 26

Page 15 of 26

Environmental Science & Technology

283

< 0.001). Strong linear relationships of log-transformed concentrations of linear and branched

284

PFAAs between the maternal-cord sera and maternal-placentas were observed (Table 1). These

285

empirical relationships may help to assess prenatal exposure by predicting concentrations in cord

286

sera based on maternal concentrations. Conversely, it may be possible to estimate linear and

287

branched PFAAs concentrations in maternal sera using the concentrations in the cord sera, which

288

is a relatively more less-invasive approach. Zhang et al. (2013) reported that levels of PFAAs in

289

human urine were positively correlated with levels in human blood, indicating urine

290

concentration can be a good surrogate measure of internal exposure. Non-invasive screening can

291

be used for epidemiological and biomonitoring studies.14

292

The occurrence of PFAAs in cord sera reveals the potential for neonatal exposure.

293

Fetuses are more sensitive to chemical exposure during embryonic and fetal development, where

294

even low dose exposure may lead to risks of irreversible damage or diseases in their later life.17,

295

18

296

accumulate in fetal cord blood.

Our findings clearly demonstrated that many PFAAs can effectively cross the placenta and

297

The association between isomer-specific PFAA concentrations in maternal sera, cord sera,

298

placentas and demographic characteristics of mothers and fetuses was also investigated in the

299

present study. Maternal /fetal characteristics included maternal age, parity, pregnancy weight

300

gain, as well as gender and gestational age of fetuses etc. (see Table S1). No correlations were

301

observed between PFAA concentrations and these maternal /fetal characteristics. This may be

302

due to the limited sample size of this study.

303

Implications for human health risk assessment. To our knowledge, this is the first study to

304

report the occurrence of isomer-specific PFAAs in placenta and placental-maternal serum

15 ACS Paragon Plus Environment

Environmental Science & Technology

305

transfer efficiency in humans. The occurrence of n- and br-PFHxS in umbilical cord serum and

306

placenta was also studied for the first time. The findings help to further understand the governing

307

mechanisms related to the placental transfer of PFAA isomers.

308

While the sample size in the present study is relatively small (32 maternal-fetal pairs), the

309

results provide insights into the exposure source and placental transfer efficiency of linear and

310

branched PFAAs. Based on these findings, more comprehensive studies encompassing a larger

311

sample size would be useful. Different transporter proteins (e.g., serum albumin, OATs) and

312

phospholipids in maternal /cord serum and placenta may influence the placental transport rates

313

and distribution of these chemicals.4, 54, 55 Thus, future studies of protein binding and

314

phospholipid partitioning behavior of PFAAs in serum and tissues may provide further insights

315

into placental transfer and prenatal exposure risks of these important contaminants of concern.

316

ASSOCIATED CONTENT

317

Supporting Information. Additional information including supplemental tables (Tables S1-S6)

318

and supplemental figure (Figure S1) is available free of charge via the Internet at

319

http://pubs.acs.org.

320

Acknowledgments. This work was supported by the National Natural Science Foundation of

321

China (Key Program Grant No. 21427815 and International Cooperation Grant No.

322

21320102007) and the China Postdoctoral Science Foundation (Grant No. 2015M580514). We

323

thank the medical staffs at the Wuhan No.1 Hospital for collecting the serum and placenta

324

samples.

16 ACS Paragon Plus Environment

Page 16 of 26

Page 17 of 26

Environmental Science & Technology

LITERATURE CITED (1) Yoo, H.; Kannan, K.; Kim, S. K.; Lee, K. T.; Newsted, J. L.; Giesy, J. P. Perfluoroalkyl acids in the egg yolk of birds from Lake Shihwa, Korea. Environ. Sci. Technol. 2008, 42 (15), 5821-7. (2) D'eon, J. C.; Mabury, S. A. Production of perfluorinated carboxylic acids (PFCAs) from the biotransformation of polyfluoroalkyl phosphate surfactants (PAPS): exploring routes of human contamination. Environ. Sci. Technol. 2007, 41 (13), 4799-805. (3) Gebbink, W. A.; Berger, U.; Cousins, I. T. Estimating human exposure to PFOS isomers and PFCA homologues: the relative importance of direct and indirect (precursor) exposure. Environ. Int. 2015, 74, 160-169. (4) Chen, F.; Gong, Z.; Kelly, B. C. Bioavailability and bioconcentration potential of perfluoroalkyl-phosphinic and-phosphonic acids in zebrafish (Danio rerio): Comparison to perfluorocarboxylates and perfluorosulfonates. Sci. Total Environ. 2016, 568, 33-41. (5) Zhang, Y.; Jiang, W.; Fang, S.; Zhu, L.; Deng, J. Perfluoroalkyl acids and the isomers of perfluorooctanesulfonate and perfluorooctanoate in the sera of 50 new couples in Tianjin, China. Environ. Int. 2014, 68, 185-191. (6) Beesoon, S.; Webster, G. M.; Shoeib, M.; Hamer, T.; Benskin, J. P.; Martin, J. W. Isomer profiles of perfluorochemicals in matched maternal, cord, and house dust samples: manufacturing sources and transplacental transfer. Environ. Health Perspect. 2011, 119 (11), 1659. (7) Paul, A. G.; Jones, K. C.; Sweetman, A. J. A first global production, emission, and environmental inventory for perfluorooctane sulfonate. Environ. Sci. Technol. 2009, 43 (2), 386392. (8) Prevedouros, K.; Cousins, I. T.; Buck, R. C.; Korzeniowski, S. H. Sources, Fate and transport of perfluorocarboxylates. Environ. Sci. Technol. 2006, 40 (1), 32-44. (9) Benskin, J. P.; Yeung, L. W. Y.; Yamashita, N.; Taniyasu, S.; Lam, P. K. S.; Martin, J. W. Perfluorinated acid isomer profiling in water and quantitative assessment of manufacturing source. Environ. Sci. Technol. 2010, 44 (23), 9049-9054. (10) Loveless, S. E.; Finlay, C.; Everds, N. E.; Frame, S. R.; Gillies, P. J.; O’Connor, J. C.; Powley, C. R.; Kennedy, G. L. Comparative responses of rats and mice exposed to linear/branched, linear, or branched ammonium perfluorooctanoate (APFO). Toxicology 2006, 220 (2–3), 203-217. (11) Benskin, J. P.; De Silva, A. O.; Martin, L. J.; Arsenault, G.; McCrindle, R.; Riddell, N.; Mabury, S. A.; Martin, J. W. Disposition of perfluorinated acid isomers in Sprague-Dawley rats; part 1: single dose. Environ. Toxicol. Chem. 2009, 28 (3), 542-554. (12) De Silva, A. O.; Benskin, J. P.; Martin, L. J.; Arsenault, G.; McCrindle, R.; Riddell, N.; Martin, J. W.; Mabury, S. A. Disposition of perfluorinated acid isomers in Sprague-Dawley rats; part 2: subchronic dose. Environ. Toxicol. Chem. 2009, 28 (3), 555-567. (13) Sharpe, R. L.; Benskin, J. P.; Laarman, A. H.; MacLeod, S. L.; Martin, J. W.; Wong, C. S.; Goss, G. G. Perfluorooctane sulfonate toxicity, isomer-specific accumulation, and maternal transfer in zebrafish (Danio rerio) and rainbow trout (Oncorhynchus mykiss). Environ. Toxicol. Chem. 2010, 29 (9), 1957-1966. (14) Zhang, Y.; Beesoon, S.; Zhu, L.; Martin, J. W. Biomonitoring of perfluoroalkyl acids in human urine and estimates of biological half-life. Environ. Sci. Technol. 2013, 47 (18), 1061910627. 17 ACS Paragon Plus Environment

Environmental Science & Technology

(15) Gao, Y.; Fu, J.; Cao, H.; Wang, Y.; Zhang, A.; Liang, Y.; Wang, T.; Zhao, C.; Jiang, G. Differential accumulation and elimination behavior of perfluoroalkyl acid isomers in occupational workers in a manufactory in China. Environ. Sci. Technol. 2015, 49 (11), 69536962. (16) De Silva, A. O.; Mabury, S. A. Isomer distribution of perfluorocarboxylates in human blood: potential correlation to source. Environ. Sci. Technol. 2006, 40 (9), 2903-9. (17) Roze, E.; Meijer, L.; Bakker, A.; Van Braeckel, K. N.; Sauer, P. J.; Bos, A. F. Prenatal exposure to organohalogens, including brominated flame retardants, influences motor, cognitive, and behavioral performance at school age. Environ. Health Perspect. 2009, 117 (12), 1953-1958. (18) Ren, A.; Qiu, X.; Jin, L.; Ma, J.; Li, Z.; Zhang, L.; Zhu, H.; Finnell, R. H.; Zhu, T. Association of selected persistent organic pollutants in the placenta with the risk of neural tube defects. P. Natl. Acad. Sci. USA 2011, 108 (31), 12770-12775. (19) Yin, S.; Tang, M.; Chen, F.; Li, T.; Liu, W. Environmental exposure to polycyclic aromatic hydrocarbons (PAHs): The correlation with and impact on reproductive hormones in umbilical cord serum. Environ. Pollut. 2017, 220, Part B, 1429-1437. (20) Longnecker, M. P.; Klebanoff, M. A.; Zhou, H.; Brock, J. W. Association between maternal serum concentration of the DDT metabolite DDE and preterm and small-for-gestational-age babies at birth. The Lancet 2001, 358 (9276), 110-114. (21) Turyk, M. E.; Persky, V. W.; Imm, P.; Knobeloch, L.; Chatterton Jr, R.; Anderson, H. A. Hormone disruption by PBDEs in adult male sport fish consumers. Environ. Health Perspect. 2008, 116 (12), 1635-1641. (22) Vreugdenhil, H. J.; Slijper, F. M.; Mulder, P. G.; Weisglas-Kuperus, N. Effects of perinatal exposure to PCBs and dioxins on play behavior in Dutch children at school age. Environ. Health Perspect. 2002, 110 (10), 593-598. (23) Hanssen, L.; Röllin, H.; Odland, J. Ø.; Moe, M. K.; Sandanger, T. M. Perfluorinated compounds in maternal serum and cord blood from selected areas of South Africa: results of a pilot study. J. Environ. Monit. 2010, 12 (6), 1355-1361. (24) Benskin, J. P.; Bataineh, M.; Martin, J. W. Simultaneous characterization of perfluoroalkyl carboxylate, sulfonate, and sulfonamide isomers by liquid chromatography-tandem mass spectrometry. Anal. Chem. 2007, 79 (17), 6455-64. (25) Kuklenyik, Z.; Reich, J. A.; Tully, J. S.; Needham, L. L.; Calafat, A. M. Automated solidphase extraction and measurement of perfluorinated organic acids and amides in human serum and milk. Environ. Sci. Technol. 2004, 38 (13), 3698-704. (26) Frederiksen, M.; Thomsen, C.; Frøshaug, M.; Vorkamp, K.; Thomsen, M.; Becher, G.; Knudsen, L. E. Polybrominated diphenyl ethers in paired samples of maternal and umbilical cord blood plasma and associations with house dust in a Danish cohort. Int. J. Hyg. Environ. Health 2010, 213 (4), 233-242. (27) Needham, L. L.; Grandjean, P.; Heinzow, B.; Jørgensen, P. J.; Nielsen, F.; Patterson Jr, D. G.; Sjödin, A.; Turner, W. E.; Weihe, P. Partition of environmental chemicals between maternal and fetal blood and tissues. Environ. Sci. Technol. 2011, 45 (3), 1121-1126. (28) Shmukler, M. Density of blood. The Physics Factbook 2004. (29) Zhang, Y.; Beesoon, S.; Zhu, L.; Martin, J. W. Isomers of perfluorooctanesulfonate and perfluorooctanoate and total perfluoroalkyl acids in human serum from two cities in North China. Environ. Int. 2013, 53, 9-17. (30) Kannan, K.; Corsolini, S.; Falandysz, J.; Fillmann, G.; Kumar, K. S.; Loganathan, B. G.; Mohd, M. A.; Olivero, J.; Van Wouwe, N.; Yang, J. H.; Aldoust, K. M. Perfluorooctanesulfonate 18 ACS Paragon Plus Environment

Page 18 of 26

Page 19 of 26

Environmental Science & Technology

and related fluorochemicals in human blood from several countries. Environ. Sci. Technol. 2004, 38 (17), 4489-4495. (31) Taniyasu, S.; Kannan, K.; Horii, Y.; Hanari, N.; Yamashita, N. A survey of perfluorooctane sulfonate and related perfluorinated organic compounds in water, fish, birds, and humans from Japan. Environ. Sci. Technol. 2003, 37, 2634-2639. (32) Fei, C.; McLaughlin, J. K.; Tarone, R. E.; Olsen, J. Perfluorinated chemicals and fetal growth: a study within the Danish National Birth Cohort. Environ. Health Perspect. 2007, 115 (11), 1677-1682. (33) Fromme, H.; Mosch, C.; Morovitz, M.; Alba-Alejandre, I.; Boehmer, S.; Kiranoglu, M.; Faber, F.; Hannibal, I.; Genzel-Boroviczény, O.; Koletzko, B. Pre-and postnatal exposure to perfluorinated compounds (PFCs). Environ. Sci. Technol. 2010, 44 (18), 7123-7129. (34) Kim, S.-K.; Lee, K. T.; Kang, C. S.; Tao, L.; Kannan, K.; Kim, K.-R.; Kim, C.-K.; Lee, J. S.; Park, P. S.; Yoo, Y. W. Distribution of perfluorochemicals between sera and milk from the same mothers and implications for prenatal and postnatal exposures. Environ. Pollut. 2011, 159 (1), 169-174. (35) Zhang, T.; Sun, H.; Lin, Y.; Qin, X.; Zhang, Y.; Geng, X.; Kannan, K. Distribution of polyand perfluoroalkyl substances in matched samples from pregnant women and carbon chain length related maternal transfer. Environ. Sci. Technol. 2013, 47 (14), 7974-7981. (36) Kärrman, A.; Ericson, I.; van Bavel, B.; Darnerud, P. O.; Aune, M.; Glynn, A.; Lignell, S.; Lindström, G. Exposure of perfluorinated chemicals through lactation: levels of matched human milk and serum and a temporal trend, 1996-2004, in Sweden. Environ. Health Perspect. 2007, 115 (2), 226-230. (37) Rylander, C.; Brustad, M.; Falk, H.; Sandanger, T. M. Dietary predictors and plasma concentrations of perfluorinated compounds in a coastal population from northern Norway. J. Environ. Public Health 2009, 2009, 10 pages. (38) Thornburg, K. L.; Kolahi, K.; Pierce, M.; Valent, A.; Drake, R.; Louey, S. Biological features of placental programming. Placenta 2016, 48, Supplement 1, 47-53. (39) Myllynen, P. K. K.; Pienimäki, P. K. K.; Vähäkangas, K. H. Transplacental passage of lamotrigine in a human placental perfusion system in vitro and in maternal and cord blood in vivo. Eur. J. Clin. Pharmacol. 2003, 58 (10), 677-682. (40) Korourian, S.; Casas, L. D. L. Normal and abnormal placentation. In Clinical obstetrics: the fetus & mother, Blackwell Publishing, Inc.: 2008; pp 33-58. (41) Syme, M. R.; Paxton, J. W.; Keelan, J. A. Drug transfer and metabolism by the human placenta. Clin. Pharmacokinet. 2004, 43 (8), 487-514. (42) van der Aa, E. M.; Copius Peereboom-Stegeman, J. H. J.; Noordhoek, J.; Gribnau, F. W. J.; Russel, F. G. M. Mechanisms of drug transfer across the human placenta. Pharm. World Sci. 1998, 20 (4), 139-148. (43) Sastry, B. V. R. Techniques to study human placental transport. Adv. Drug Del. Rev. 1999, 38 (1), 17-39. (44) Hill, M. D.; Abramson, F. P. The significance of plasma protein binding on the fetal/maternal distribution of drugs at steady-state. Clin. Pharmacokinet. 1988, 14 (3), 156-170. (45) Beesoon, S.; Martin, J. W. Isomer-specific binding affinity of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) to serum proteins. Environ. Sci. Technol. 2015, 49 (9), 5722-5731. (46) Vähäkangas, K.; Myllynen, P. Drug transporters in the human blood‐placental barrier. Br. J. Pharmacol. 2009, 158 (3), 665-678. 19 ACS Paragon Plus Environment

Environmental Science & Technology

(47) Iqbal, M.; Audette, M. C.; Petropoulos, S.; Gibb, W.; Matthews, S. G. Placental drug transporters and their role in fetal protection. Placenta 2012, 33 (3), 137-142. (48) Klaassen, C. D.; Lu, H. Xenobiotic transporters: ascribing function from gene knockout and mutation studies. Toxicol. Sci. 2008, 101 (2), 186-196. (49) Kummu, M.; Sieppi, E.; Koponen, J.; Laatio, L.; Vähäkangas, K.; Kiviranta, H.; Rautio, A.; Myllynen, P. Organic anion transporter 4 (OAT 4) modifies placental transfer of perfluorinated alkyl acids PFOS and PFOA in human placental ex vivo perfusion system. Placenta 2015, 36 (10), 1185-1191. (50) Pan, Y.; Zhu, Y.; Zheng, T.; Cui, Q.; Buka, S. L.; Zhang, B.; Guo, Y.; Xia, W.; Yeung, L. W.-Y.; Li, Y. Novel Chlorinated Polyfluorinated Ether Sulfonates and Legacy Per/Polyfluoroalkyl Substances: Placental Transfer and Relationship with Serum Albumin and Glomerular Filtration Rate. Environ. Sci. Technol. 2017, 51 (1), 634-644. (51) Soveri, I.; Berg, U. B.; Björk, J.; Elinder, C.-G.; Grubb, A.; Mejare, I.; Sterner, G.; Bäck, S.E. Measuring GFR: a systematic review. Am. J. Kidney Dis. 2014, 64 (3), 411-424. (52) Sagiv, S. K.; Rifas-Shiman, S. L.; Webster, T. F.; Mora, A. M.; Harris, M. H.; Calafat, A. M.; Ye, X.; Gillman, M. W.; Oken, E. Sociodemographic and perinatal predictors of early pregnancy per- and polyfluoroalkyl substance (PFAS) concentrations. Environ. Sci. Technol. 2015, 49 (19), 11849-11858. (53) Rizwan, A. N.; Burckhardt, G. Organic anion transporters of the SLC22 family: biopharmaceutical, physiological, and pathological roles. Pharm. Res. 24 (3), 450-470. (54) Armitage, J. M.; Arnot, J. A.; Wania, F. Potential role of phospholipids in determining the internal tissue distribution of perfluoroalkyl acids in biota. Environ. Sci. Technol. 2012, 46 (22), 12285-12286. (55) Armitage, J. M.; Arnot, J. A.; Wania, F.; Mackay, D. Development and evaluation of a mechanistic bioconcentration model for ionogenic organic chemicals in fish. Environ. Toxicol. Chem. 2013, 32 (1), 115-128.

20 ACS Paragon Plus Environment

Page 20 of 26

Page 21 of 26

Environmental Science & Technology

Figure Captions Figure 1. Box chart of total PFHxS, PFOS and PFOA concentrations in matched maternal serum (ng/mL), cord serum (ng/mL) and placenta (ng/g). The boxes mark the 25th, 50th and 75th percentiles, respectively. Squares within the boxes indicate the mean values. The whiskers represent 5th and 95th percentiles. The crosses below or above the whiskers indicate outlier values. Figure 2. Isomer compositions of PFHxS, PFOS and PFOA in maternal serum, cord serum and placenta (%, median). Figure 3. Box chart of cord-maternal (RCM, dimensionless) and placental-maternal (RPM, dimensionless) ratios for total PFHxS, PFOS and PFOA. The boxes mark the 25th, 50th and 75th percentiles, respectively. Squares within the boxes indicate the mean values. The whiskers represent 5th and 95th percentiles. The crosses below or above the whiskers indicate outlier values. Figure 4. Box chart of isomer-specific (A) cord-maternal (RCM, dimensionless) and (B) placental-maternal (RPM, dimensionless) ratios for PFHxS, PFOS and PFOA. The boxes mark the 25th, 50th and 75th percentiles, respectively. Squares within the boxes indicate the mean values. The whiskers represent 5th and 95th percentiles. The crosses below or above the whiskers indicate outlier values.

21 ACS Paragon Plus Environment

Environmental Science & Technology

Page 22 of 26

Table 1. Linear regression equations between logC-logMa and logP-logMa for linear and branched PFAAs. Compound Equation (C-M) R2 Equation (P-M) n-PFHxS logC = 1.19 logM +0.05 0.75 logP = 1.13 logM -0.12 ΣPFHxS logC = 1.34 logM -0.15 0.77 logP = 0.91 logM -0.42 n-PFOS logC = 1.10 logM -0.52 0.77 logP = 1.08 logM -0.53 iso-PFOS logC = 1.12 logM -0.38 0.81 logP = 1.00 logM -0.53 (3+5)m-PFOS logC = 1.42 logM +0.77 0.59 logP = 1.04 logM -0.09 4m-PFOS logC = 1.42 logM +0.26 0.49 logP = 1.02 logM -0.05 1m-PFOS logC = 1.36 logM +0.41 0.68 logP = 1.14 logM +0.13 Σm2-PFOS logC = 1.12 logM +0.23 0.59 NAb ΣPFOS logC = 0.97 logM -0.36 0.77 logP = 1.08 logM -0.58 n-PFOA logC = 0.89 logM -0.10 0.45 logP = 0.89 logM -0.51 ΣPFOA logC = 0.89 logM -0.11 0.53 logP = 0.87 logM -0.49 a C: cord serum concentration; M: maternal serum concentration; P: placenta concentration b NA: not available

22

ACS Paragon Plus Environment

R2 0.80 0.79 0.86 0.82 0.70 0.61 0.83 NA 0.86 0.66 0.66

Page 23 of 26

Environmental Science & Technology

Figure 1.

23

ACS Paragon Plus Environment

Environmental Science & Technology

Figure 2.

24

ACS Paragon Plus Environment

Page 24 of 26

Page 25 of 26

Environmental Science & Technology

Figure 3.

25

ACS Paragon Plus Environment

Environmental Science & Technology

Figure 4.

26 ACS Paragon Plus Environment

Page 26 of 26