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Journal ArticleDOI

Perfluoroalkyl Acids (PFAAs) in Children's Serum and Contribution from PFAA-Contaminated Drinking Water.

TL;DR: Investigation of associations between serum perfluoroalkyl acid concentrations in children aged 4, 8, and 12 years and exposure via placental transfer, breast-feeding, and ingestion of PFAA-contaminated drinking water found early life exposure to PFOA, PFHxS, and PFOS is an important determinant of serum concentrations inChildren, with the strongest influence on younger ages.
Abstract: We investigated associations between serum perfluoroalkyl acid (PFAA) concentrations in children aged 4, 8, and 12 years (sampled in 2008-2015; n = 57, 55, and 119, respectively) and exposure via placental transfer, breastfeeding, and ingestion of PFAA-contaminated drinking water. Sampling took place in Uppsala County, Sweden, where the drinking water has been historically contaminated with perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS), perfluorooctanesulfonate (PFOS), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA). PFOS showed the highest median concentrations in serum (3.8-5.3 ng g-1 serum), followed by PFHxS (1.6-5.0 ng g-1 serum), PFOA (2.0-2.5 ng g-1 serum), and perfluorononanoate (PFNA) (0.59-0.69 ng g-1 serum) in children. Including all children, serum PFOA, PFHxS, and PFOS concentrations in children increased 10, 10, and 1.3% (adjusted mean), respectively, per unit (ng g-1 serum) of increase in the maternal serum level (at delivery), the associations being strongest for 4 year-old children. PFHxS and PFOS significantly increased 3.9 and 3.8%, respectively, per month of nursing, with the highest increase for 4 year-olds. PFOA, PFBS, PFHxS, and PFOS increased 1.2, 207, 7.4, and 0.93%, respectively, per month of cumulative drinking water exposure. Early life exposure to PFOA, PFHxS, and PFOS is an important determinant of serum concentrations in children, with the strongest influence on younger ages. Drinking water with low to moderate PFBS, PFHxS, PFOS, and PFOA contamination is an important source of exposure for children with background exposure from other sources.

Summary (2 min read)

Introduction

  • Per- and polyfluoroalkyl substances are synthetic highly fluorinated substances that have been produced in large volumes and which have broad commercial applications.
  • PFASs are ubiquitous in humans and the environment.
  • 21, 22 Other exposure media like diet, drinking water, dust and air contribute to a greater extent as the child gets older.
  • Drinking water in the City of Uppsala, Sweden, was contaminated with PFAAs for at least 20 years 37 before the contamination was discovered in 2012 and affected production wells were 5 closed or severely restricted.

Sampling

  • All mother/child pairs included in the present paper are participants in the POPUP study, an on-going investigation of POPs in first-time mothers and their children in Uppsala County, Sweden.
  • Mothers were randomly recruited during pregnancy (1996-1999) or shortly after delivery (2000-2011).39, 40 The mothers answered a self-administered questionnaire about life-style factors and health of the mother and child.
  • Blood samples from the mothers were collected 3 weeks after delivery.
  • The study was approved by the local ethics committee in Uppsala, Sweden (dnr 2004/177 and 2007/147/1), and the participating women and children gave informed consent.

Chemical analyses

  • A total of 13 PFAAs were targeted in the present work, including C4, C6 and C8 perfluoroalkane sulfonic acids (PFSA; i.e. PFBS, PFHxS, PFOS) and C6-C15 perfluoroalkyl carboxylic acids (PFCA; i.e. PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, PFTeDA, PFPeDA; for details see Supporting Information, Table A1).
  • Quantification was performed by isotope dilution using a 5-point calibration curve (linear, 1/x weighting), which was run before and after samples.
  • For PFBS, PFTrDA, PFTeDA, and PFPeDA, a structurally similar internal standard was used (Supporting Information, Table A2).
  • A procedural blank and a quality control (QC) sample (pooled human serum analyzed repeatedly in-house) were included with every batch of samples to assess background contamination and reproducibility, respectively (see Supporting Information Table A3 for QC performance metrics).
  • For targets observable in method blanks, the detection limit was based on the mean blank + 3× the standard deviation of the blanks.

Exposure via drinking water

  • Data on the occurrence of PFAAs in drinking water were only available for a few samples (n=9) collected at the tap in different parts of Uppsala County in 2012, when PFAA contamination was first discovered.
  • Modeling the distribution of contaminated well water from 1996 to 2012 made it possible to estimate the extent of exposure to PFAA-contaminated water depending on location of residence within Uppsala County.
  • The cumulative number of months with PFAA exposure from drinking water were calculated for the five PFAAs that were detected in the drinking water: PFHpA, PFOA, PFBS, PFHxS, and PFOS.
  • After July 2012, it was assumed that no district received contaminated water (i.e. DWexp = 0).
  • In the next step, each DWexp was half-life-adjusted based on the number of months between the month in question and blood sampling.

Statistical analyses

  • MINITAB 15® Statistical Software for Windows was used for all statistical analyses.
  • General linear model (GLM) analysis was used to investigate differences in serum PFAA concentrations between age groups, adjusted for sampling year and drinking water exposure.
  • When analyzing %br PFHxS or PFOS in children, the maternal serum %br PFHxS or PFOS was included instead of maternal concentrations of PFHxS or PFOS.
  • For children sampled both at 8 and 12 years of age, the results from age 8 were used, due to a smaller sample size than among 12-year-old children.
  • A sensitivity test was performed when observations with standardized residuals ≥3 were excluded from analysis due to their large influence on the regression results.

PFAA serum concentrations

  • PFAA serum concentrations in children at different ages are presented in Table 2 and Table 3 .
  • Studies reporting age- dependent differences in PFAA concentrations among children have observed diverging results.
  • Previous studies in adults have reported a slightly higher percentage of br PFOS isomers in human serum than in the historical technical mixture.
  • A few marginally non- significant associations in the basic model became significant in the full model.

Drinking water exposure

  • When including all children in the MLR models, serum concentrations in children increased with increasing drinking water exposure for PFOA, PFBS, PFHxS, and PFOS (Table 4).
  • 20 The %br PFHxS and %br PFOS in children’s serum were positively associated with cumulative drinking water exposure, with a stronger association for %br PFHxS (R2=0.15) than for %br PFOS (R2=0.02) (Table 4).
  • A = significantly different from 4-year- olds and b = significantly different from 8-year-olds (p<0.05).
  • PFSA concentrations measured in 3 replicates of NIST SRM 1957 compared to reference values (Table A5).
  • Mean percent changes of serum PFAA concentrations including all children and results from the age categories, with age 4 as the reference category (Table A8).

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This is an author produced version of a paper published in
Environmental Science & technology.
This paper has been peer-reviewed but may not include the final publisher
proof-corrections or pagination.
Citation for the published paper:
Irina Gyllenhammar, Jonathan P. Benskin, Oskar Sandblom, Urs Berger,
Lutz Ahrens, Sanna Lignell, Karin Wiberg, Anders Glynn. (2019)
Perfluoroalkyl Acids (PFAAs) in Children’s Serum and Contribution from
PFAA-Contaminated Drinking Water. Environmental Science & technology.
Volume: 53, Number: 19, pp 11447-11457.
https://doi.org/10.1021/acs.est.9b01746
Access to the published version may require journal subscription.
Published with permission from: ACS.
Standard set statement from the publisher:
“This document is the Accepted Manuscript version of a Published Work that appeared in
final form in Environmental Science & Technology, copyright © American Chemical
Society, after peer review and technical editing by the publisher. To access the final edited
and published work see https://doi.org/10.1021/acs.est.9b01746 .
Epsilon Open Archive http://epsilon.slu.se

Perfluoroalkyl acids (PFAAs) in children’s serum and contribution from PFAA
contaminated drinking water
Irina Gyllenhammar,
*
Jonathan P. Benskin,
Oskar Sandblom,
Urs Berger,
§
Lutz Ahrens,
#
Sanna Lignell,
Karin Wiberg,
#
Anders Glynn
¤
Department of Risk and Benefit Assessment, National Food Agency, P.O. Box 622, SE-751
26 Uppsala, Sweden
Department of Environmental Science and Analytical Chemistry (ACES), Stockholm
University, SE-106 91 Stockholm, Sweden
§
Helmholtz Centre for Environmental Research (UFZ), Department Analytical Chemistry,
Permoserstr. 15, DE-04318 Leipzig, Germany
#
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural
Sciences (SLU), Box 7050, SE-750 07, Uppsala, Sweden
¤
Department of Biomedical Sciences and Veterinary Public Health, Swedish University of
Agricultural Sciences (SLU), Box 7028, SE-750 07, Uppsala, Sweden
*Corresponding author:
Irina Gyllenhammar
Department of Risk and Benefit Assessment, National Food Agency, P.O. Box 622, SE-751
26 Uppsala, Sweden Telephone: int + 46 18 174326
E-mail: irina.gyllenhammar@slu.se

2
Abstract
We investigated associations between serum perfluoroalkyl acid (PFAA) concentrations in
children aged 4, 8, and 12 years (sampled in 2008-2015; n=57, 55, and 119, respectively) and
exposure via placental transfer, breast-feeding, and ingestion of PFAA-contaminated drinking
water. Sampling took place in Uppsala County, Sweden, where the drinking water has been
historically contaminated with perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate
(PFHxS), perfluorooctanesulfonate (PFOS), perfluoroheptanoate (PFHpA), and
perfluorooctanoate (PFOA). PFOS showed the highest median concentrations in serum (3.8-
5.3 ng g
-1
serum) followed by PFHxS (1.6-5.0 ng g
-1
serum), PFOA (2.0-2.5 ng g
-1
serum),
and perfluorononanoate (PFNA) (0.59-0.69 ng g
-1
serum) in children. Including all children,
serum PFOA, PFHxS, and PFOS concentrations in children increased 10%, 10%, and 1.3%
(adjusted mean), respectively, per unit (ng g
-1
serum) of increase in maternal serum level (at
delivery), the associations being strongest for 4-year-old children. PFHxS and PFOS
significantly increased 3.9% and 3.8%, respectively, per month of nursing, with the highest
increase for 4-year-olds. PFOA, PFBS, PFHxS, and PFOS increased 1.2%, 207%, 7.4%, and
0.93%, respectively, per month of cumulative drinking water exposure. Early life exposure to
PFOA, PFHxS, and PFOS is an important determinant of serum concentrations in children,
with the strongest influence on younger ages. Drinking water with low to moderate PFBS,
PFHxS, PFOS, and PFOA contamination is an important source of exposure for children with
background exposure from other sources.

3
TOC Graphic

4
Introduction
Per- and polyfluoroalkyl substances (PFASs) are synthetic highly fluorinated substances that
have been produced in large volumes and which have broad commercial applications. PFASs
are ubiquitous in humans and the environment. Human exposure media include food,
drinking water, dust, air and products containing PFASs.
1
2
3
Perfluoroalkyl acids (PFAAs)
are a class of PFASs which are intentionally manufactured, but which may also occur from
degradation of other PFASs (i.e. PFAA-precursors).
4
5
PFAAs display extreme environmental
persistence and chain length-dependent bioaccumulation in humans.
6, 7
For the general population, exposure to PFAAs via placental transfer
8-11
and ingestion of
mother´s milk
12-14
are major determinants of blood PFAAs concentrations in infants.
15-20
In
fact, exposure to certain PFAAs via breast milk as an infant represents a significant fraction
of a child’s overall exposure up to 3-5 years of age, most probably due to the long half-lives
of these PFAAs in the body.
21, 22
Other exposure media like diet, drinking water, dust and air
contribute to a greater extent as the child gets older.
22-26
Early life exposure to some PFAAs
during pregnancy has been associated with lower birth weight
27-29
and increased childhood
adiposity.
30-33
Positive associations between maternal PFAA levels during pregnancy and
children’s weight or body mass index (BMI) have also been reported
29, 31, 34
along with
relations to immune toxicity in children.
35, 36
Improved knowledge of the determinants of
blood PFAA concentrations in infants/children, in particular in scenarios involving point
source contamination (e.g. contaminated drinking water) is needed for understanding the
exposure sources responsible for observed relationships between blood PFAA concentrations
and health outcomes.
Drinking water in the City of Uppsala, Sweden, was contaminated with PFAAs for at least 20
years
37
before the contamination was discovered in 2012 and affected production wells were

Citations
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13 Feb 2015
TL;DR: Johnson et al. as mentioned in this paper applied the Navigation Guide methodology to determine whether developmental exposure to perfluorooctanoic acid (PFOA) affects fetal growth in humans.
Abstract: Background: The Navigation Guide methodology was developed to meet the need for a robust method of systematic and transparent research synthesis in environmental health science. We conducted a case study systematic review to support proof of concept of the method. Objective: We applied the Navigation Guide systematic review methodology to determine whether developmental exposure to perfluorooctanoic acid (PFOA) affects fetal growth in humans. Methods: We applied the first 3 steps of the Navigation Guide methodology to human epidemiological data: 1) specify the study question, 2) select the evidence, and 3) rate the quality and strength of the evidence. We developed a protocol, conducted a comprehensive search of the literature, and identified relevant studies using prespecified criteria. We evaluated each study for risk of bias and conducted meta-analyses on a subset of studies. We rated quality and strength of the entire body of human evidence. Results: We identified 18 human studies that met our inclusion criteria, and 9 of these were combined through meta-analysis. Through meta-analysis, we estimated that a 1-ng/mL increase in serum or plasma PFOA was associated with a –18.9 g (95% CI: –29.8, –7.9) difference in birth weight. We concluded that the risk of bias across studies was low, and we assigned a “moderate” quality rating to the overall body of human evidence. Conclusion: On the basis of this first application of the Navigation Guide systematic review methodology, we concluded that there is “sufficient” human evidence that developmental exposure to PFOA reduces fetal growth. Citation: Johnson PI, Sutton P, Atchley DS, Koustas E, Lam J, Sen S, Robinson KA, Axelrad DA, Woodruff TJ. 2014. The Navigation Guide—evidence-based medicine meets environmental health: systematic review of human evidence for PFOA effects on fetal growth. Environ Health Perspect 122:1028–1039; http://dx.doi.org/10.1289/ehp.1307893

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TL;DR: A combined method for quantitative analysis, along with suspect and non-target screening of per- and polyfluoroalkyl substances (PFAS) was developed using ultra-high pressure liquid chromatography-ultra-high resolution (Orbitrap) mass spectrometry, which revealed the presence of perfluoro-4-ethylcyclohexanesulfonate (PFECHS), which displayed declining trends since the year 2000.
Abstract: A combined method for quantitative analysis, along with suspect and non-target screening of per- and polyfluoroalkyl substances (PFAS) was developed using ultra-high pressure liquid chromatography-ultra-high resolution (Orbitrap) mass spectrometry. The method was applied together with measurements of total- and extractable organofluorine (TF and EOF, respectively), to pooled serum samples from 1996–2017 from first-time mothers living in the county of Uppsala, Sweden, some of which (i.e. 148 of 472 women sampled 1996–2012) were exposed to drinking water contaminated with perfluorohexane sulfonate (PFHxS) and other PFAS until mid-2012. Declining trends were observed for all target PFAS as well as TF, with homologue-dependent differences in year of onset of decline. Only 33% of samples displayed detectable EOF, and amongst these samples the percentage of EOF explained by target PFAS declined significantly (−3.5% per year) over the entire study period. This finding corroborates prior observations in Germany after the year 2000, and may reflect increasing exposure to novel PFAS which have not yet been identified. Suspect screening revealed the presence of perfluoro-4-ethylcyclohexanesulfonate (PFECHS), which displayed declining trends since the year 2000. Non-target time trend screening revealed 3 unidentified features with time trends matching PFHxS. These features require further investigation, but may represent contaminants which co-occurred with PFHxS in the contaminated drinking water.

73 citations

Journal ArticleDOI
29 Jan 2021
TL;DR: In this paper, a nanofiltration (NF) was used to remove per-and polyfluoroalkyl substances (PFASs) from drinking water in the city of Uppsala, Sweden.
Abstract: The removal of per- and polyfluoroalkyl substances (PFASs) presents a challenge for drinking water providers. Guidelines for PFAS concentrations in final drinking water are regularly updated to ever-decreasing values, and conventional drinking water treatment plants are not designed to remove PFASs. Currently, the most frequently used removal technique, adsorption to granular activated carbon (GAC), is often considered challenging. High-pressure membranes, such as nanofiltration (NF), have been shown to remove PFASs efficiently. However, the creation of a waste stream comprised of at least 10% of the feedwater volume is recognized as a major drawback of this technique. In this study, a NF pilot plant was operated at a drinking water treatment plant in the city of Uppsala, Sweden, for six months. NF removed up to >98% of PFASs and fulfilled other water quality targets, such as the removal of uranium-238, dissolved organic carbon (DOC), and mineral hardness from the raw water. The concentrate from the pilot plant was treated with two different GAC materials and two different anion exchange (AIX) resins in column tests, where the superior performance of AIX over GAC was observed in terms of PFAS removal. PFAS adsorption curves for GAC were found to superimpose each other for the two water types if normalized to the specific throughput of DOC. The application of the freely available PHREEQC model revealed improvement possibilities in terms of resin properties. A cost analysis using the column test results compared GAC filtration to the combination of NF with adsorption materials. Treatment costs were found to be largely dependent on the PFAS drinking water treatment goals and concentrate discharge requirements, which highlight the economic consequences of prevailing guidelines for drinking water and discharge to the environment. The results of this study provide both the scientific community as well as drinking water providers with important insights into the application of NF for PFAS removal during drinking water treatment as well as that mechanistic and economic aspects of NF treatment and the management of the resulting concentrate.

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TL;DR: The DW variable explained 16% (PFOA) to 78% (PFHxS) of the variation in serum PFAA concentrations, suggesting that low-level-contaminated DW is a significant source of exposure for children in Sweden.
Abstract: Little is known about the demographic/life-style/physiological determinants explaining the variation of serum perfluoroalkyl acid (PFAA) concentrations in children. We identified significant determinants in children and investigated the influence of low-level PFAA-contaminated drinking water (DW) (<10 ng L−1 of single PFAAs) on serum concentrations. Four perfluorosulfonic acids (PFSAs) and 11 perfluorocarboxylic acids (PFCAs) were analyzed in serum from 5th grade children from 11 Swedish schools (N = 200; average age: 12 years) using liquid chromatography-tandem-mass-spectrometry. Data on demography and life-style/physiological factors were obtained by questionnaires. PFAA concentrations in raw and drinking water (DW) were obtained from the water works supplying DW to the schools. In multiple regression analyses school was the determinant contributing most to the variation in PFAA concentrations, with the lowest contribution for PFHpA (10%) and the highest for PFHxS (81%). Girls had lower adjusted mean concentrations of PFHxS, PFOS, PFNA and PFDA than boys, but a higher concentration of PFHxA. Girls reporting onset of menstruation had lower PFHxS and PFOA concentrations than other girls, suggesting menstrual bleeding elimination. Children born by mothers from less industrialized countries had lower mean concentrations of both PFSAs and PFCAs than children with mothers from highly industrialized countries, suggesting differences in early-life exposure. Life-style factors associated with paternal education levels appeared to influence PFAA concentrations differently than maternal education level. Already at an average DW PFHxS concentration of 2 ng L−1, children had a significantly higher adjusted mean serum PFHxS concentration than at an average DW concentration of <1.6 ng PFHxS L−1. Similar results were observed for PFOS and PFOA. The DW variable explained 16% (PFOA) to 78% (PFHxS) of the variation in serum PFAA concentrations, suggesting that low-level-contaminated DW is a significant source of exposure for children in Sweden. Although some of the associations, especially those with menstruation and maternal birth country, should be interpreted with extra caution due to the small size of the study, the results contribute to future work on identifying populations of children at risk of elevated PFAA exposures.

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TL;DR: The calculated total amount of PFCs transferred by lactation to a breast-fed infant in this study was approximately 200 ng/day, and reference concentrations for hazard assessments are needed.
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Q1. What are the contributions mentioned in the paper "Epsilon open archive http://epsilon.slu.se perfluoroalkyl acids (pfaas) in children’s serum and contribution from pfaa contaminated drinking water" ?

In this paper, the authors investigated determinants of PFAA serum concentrations in older children at ages 4, 8, and 12 years, from the POPUP cohort, focussing on maternal PFAA concentrations at the time of delivery, nursing history of the child, and history of drinking water exposure.