| 1. |
- Glynn, A., et al.
(författare)
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Determinants of serum concentrations of perfluoroalkyl acids (PFAAs) in school children and the contribution of low-level PFAA-contaminated drinking water
- 2020
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Ingår i: Environmental Science-Processes & Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:4, s. 930-944
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Tidskriftsartikel (refereegranskat)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 5(th)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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| 2. |
- Glynn, Anders, et al.
(författare)
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PFAS i blod – modellering av exponering via dricksvatten
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med projektet var att undersöka sambandet mellan halter av per- och polyfluorerade alkylsubstanser (PFAS) i dricksvatten (DV) och i serumprover från befolkningsgrupper som druckit PFAS-förorenat DV under lång tid. Målet var att utveckla en populationsmodell där PFAS-halter i serum kan uppskattas från PFAS-halter i DV och exponeringstid för detta DV. I projektet användes redan publicerade resultat från studier av PFAS-halter i serum och DV, omfattande anställda vid Arvidsjaurs flygplats (brunnsvatten), permanent/fritidsboende i närheten av Luleå flygplats (brunnsvatten), permanent/fritidsboende i närheten av Visby flygplats (brunnsvatten), och invånare från Uppsala (kommunalt DV). En grupp vuxna från Karlshamn (kommunalt vatten) fick representera populationer som druckit rent DV. Linjära regressionsanalyser visade starka samband mellan uppmätta PFAS-halter i serum och DV. PFHxS uppvisade den högsta kvoten mellan halt i serum och DV (ca 100), medan PFHxA och PFBS hade kvoter i intervallet 1-2. Skillnaderna i kvoter, som illustrerar hur effektivt PFAS bioackumuleras i kroppen från DV, är relaterad till hur länge olika PFAS stannar i kroppen efter avslutad exponering (halveringstider). PFAS med långa halveringstider (PFOA, PFHxS, PFOS) hade klart högre kvoter, och därmed högre bioackumulering, än PFAS med korta halveringstider (PFHxA, PFBS). I separata regressionsanalyser observerades lägre kvoter mellan PFAS-halt i serum och DV hos kvinnor än hos män, vilket antyder att kvinnor inte bioackumulerar de studerade PFAS från DV i lika hög grad som män. Befolkningen i Sverige exponeras för PFAS från andra källor än DV, vilket leder till bakgrundshalter av PFAS i serum även bland dem som inte druckit förorenat DV. Resultaten från regressionsanalyserna användes för att uppskatta vid vilka halter av PFAS i DV som det med stor sannolikhet går att upptäcka PFAS-halter i serum som ligger över bakgrundshalterna. Dessa PFAS-halter i DV varierade mellan olika PFAS, från ca 50 ng/L för PFOA till ca 100 ng/L för PFOS. Dessa halter ligger mycket högre än de som normalt uppmäts i kommunalt och enskilt DV i Sverige, och representerar halter i starkt förorenade områden. Med den relativt enkla populationsmodell som utvecklats i projektet kan man beräkna hur halterna av PFAS i serum påverkas av PFAS-halterna i DV. Dessutom kan man beräkna hur PFAS-halterna i serum påverkas av exponeringstiden för det förorenade DV, samt hur halterna minskar i serum efter övergång till rent DV. Som ingångsvärden i modellen användes de bakgrundshalter av PFAS i serum och kvoter mellan serum/DV-halter av PFAS som tagits fram i regressionsanalysen. Dessutom utnyttjades de halveringstider som tagits fram för de som arbetade (och konsumerade PFAS-förorenat DV) vid Luleå flygplats, samt en population vuxna från Canada. I ett test av modellen jämfördes de modellerade halterna av PFOA, PFHxS och PFOS i serum med uppmätta halter i tre populationer från Sverige (Ronneby), Italien (Veneto) och Arnsberg (Tyskland) som druckit förorenat DV under lång tid. Jämförelsen visade att modellen på ett bra sätt uppskattar variationen av halterna i serum i populationen, men att den underskattar medelhalterna, om medianen används vid jämförelsen. Om de modellerade medelvärdena (artimetiskt medelvärde) istället används i jämförelsen med de uppmätta medianerna, ligger de modellerade och uppmätta medel-halterna nära varandra. De observerade skillnaderna kan bero på att den regressionsanalys som användes för att ta fram ingångsvärdena i modellen påverkat fördelningen av värdena på ett sätt som inte helt överensstämmer med fördelningen i de studerade populationerna. Eliminering av PFAS efter övergång till rent DV modellerades också. Som exempel användes haltdata från de Ronnebybor som druckit förorenat DV under lång tid. Som slutpunkt i modelleringen användes den serumhalt som i medeltal representerar ett långsiktigt intag av PFAS i nivå med det tolerabla veckointaget (serumTVI), som EFSA tagit fram i sin senaste riskbedömning. SerumTVI är uppskattat för en summa-halt av PFOA, PFNA, PFHxS och PFOS i serum (6,9 ng PFAS4/ml). Modelleringen pekar mot en stor variation i den tid det tar innan serumTVI nås i en befolkningsgrupp efter byte till rent DV. Den kortaste tiden modellerades till 14 år och den längsta till längre än en livstid. Resultaten i projektet uppmuntrar till fortsatt utveckling av modellen för uppskattning av PFAS-halter i serum från uppmätta halter i DV.
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| 3. |
- Johanson, G., et al.
(författare)
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Quantitative relationships of perfluoroalkyl acids in drinking water associated with serum concentrations above background in adults living near contamination hotspots in Sweden
- 2023
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 219
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Tidskriftsartikel (refereegranskat)abstract
- Contaminated drinking water (DW) is a major source of exposure to per- and polyfluoroalkyl substances (PFAS) at locations around PFAS production/use facilities and military airports. This study aimed to investigate quantitative relationships between concentrations in DW and serum of nine perfluoroalkyl acids (PFAAs) in Swedish adult populations living near contamination hotspots. Short-chained (PFPeA, PFHxA, PFHpA, and PFBS) and long-chained PFAAs (PFOA, PFNA, PFDA, PFHxS and PFOS) were measured in DW and serum. We matched DW and serum concentrations for a total of 398 subjects living or working in areas receiving contaminated DW and in one non-contaminated area. Thereafter, linear regression analysis with and without adjustments for co-variates was conducted. This enabled to derive (i) serum concentrations at background exposure (CB) from sources other than local DW exposure (i.e. food, dust and textiles) at 0 ng/L DW concentration, (ii) population-mean PFAA serum:water ratios (SWR) and (iii) PFAA concentrations in DW causing observable elevated serum PFAA concentrations above background variability. Median concentrations of the sum of nine PFAAs ranged between 2.8 and 1790 ng/L in DW and between 7.6 and 96.9 ng/mL in serum. DW concentration was the strongest predictor, resulting in similar unadjusted and adjusted regression coefficients. Mean CB ranged from <0.1 (PFPeA, PFHpA, PFBS) to 5.1 ng/mL (PFOS). Serum concentrations increased significantly with increasing DW concentrations for all PFAAs except for PFPeA with SWRs ranging from <10 (PFHxA, PFHpA and PFBS) to 111 (PFHxS). Observed elevated serum concentrations above background variability were reached at DW concentrations between 24 (PFOA) and 357 ng/L (PFHxA). The unadjusted linear regression predictions agreed well with serum concentrations previously reported in various populations exposed to low and high DW levels of PFOA, PFHxS and PFOS. The quantitative relationships derived herein should be helpful to translate PFAA concentrations in DW to concentrations in serum at the population level.
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| 4. |
- Rydén, Andreas, 1981-, et al.
(författare)
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Synthesis and tentative identification of novel polybrominated diphenyl ether metabolites in human blood
- 2012
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 88:10, s. 1227-1234
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Tidskriftsartikel (refereegranskat)abstract
- Hydroxylated polybrominated diphenyl ethers (OH-PDBEs) are exogenous, bioactive compounds that originate, to a large extent, from anthropogenic activities, although they are also naturally produced in the environment. In the present study nine new authentic OH-PBDE reference standards and their corresponding methyl ether derivatives (MeO-PBDEs) were synthesised and characterised by NMR spectroscopy and mass spectrometry. Seven of the authentic reference standards prepared were thereafter tentatively identified in a pooled human blood sample. The tentatively identified OH-PBDEs were 3-hydroxy-2,2',4,4',6-pentabromodiphenyl ether, 3'-hydroxy-2,2',4,4',6-pentabromodiphenyl ether, 3-hydroxy-2,2',4,4',5-pentabromodiphenyl ether, 3-hydroxy-2,2',4,4',5,6'-hexabromodiphenyl ether. 3'-hydroxy-2,2',4,4',5,6'-hexabromodiphenyl ether, 3-hydroxy-2,2',4,4',5,5'-hexabromodiphenyl ether and 4-hydroxy-2,2',3,4',5,5',6-heptabromodiphenyl ether. An additional seven OH-PBDEs were tentatively identified in the pooled human blood sample, of which one OH-PBDE, 4'-hydroxy-2,2',4,5,5'-pentabromodiphenyl ether, has not been identified in human blood before. The identification was performed using gas chromatography-mass spectrometry (GC-MS) recording the bromine ions m/z 79, 81. The tentative identification was supported by the peaks relative retention times (RRTs) compared to authentic references on two GC columns of different polarities for the hexa-, and heptabrominated OH-PBDEs, and three different GC columns for the pentabrominated OH-PBDEs. The OH-PBDE congeners most likely originate from human metabolism of a flame retardant, i.e. polybrominated diphenyl ethers (PBDEs), due to the relatively high concentrations of PBDEs in the same human blood sample and the fact that these PBDEs could form the tentatively identified OH-PBDEs via metabolic direct hydroxylation or via 1,2-shift.
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| 5. |
- Xu, Yiyi, et al.
(författare)
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Serum Half-Lives for Short- and Long-Chain Perfluoroalkyl Acids after Ceasing Exposure from Drinking Water Contaminated by Firefighting Foam
- 2020
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Ingår i: Environmental Health Perspectives. - 1552-9924 .- 0091-6765. ; 128:7, s. 77004-77004
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Firefighting foam-contaminated ground water, which contains high levels of perfluoroalkyl substances (PFAS), is frequently found around airports. In 2018 it was detected that employees at a municipal airport in northern Sweden had been exposed to high levels of short-chain PFAS along with legacy PFAS (i.e., PFOA, PFHxS, and PFOS) through drinking water.OBJECTIVES: In this study, we aimed to describe the PFAS profile in drinking water and biological samples (paired serum and urine) and to estimate serum half-lives of the short-chain PFAS together with legacy PFAS.METHODS: Within 2 weeks after provision of clean water, blood sampling was performed in all 26 airport employees. Seventeen of them were then followed up monthly for 5 months. PFHxA, PFHpA, PFBS, PFPeS, and PFHpS together with legacy PFAS in water and biological samples were quantified using LC/MS/MS. Half-lives were estimated by assuming one compartment, first-order elimination kinetics.RESULTS: The proportions of PFHxA, PFHpA, and PFBS were higher in drinking water than in serum. The opposite was found for PFHxS and PFOS. The legacy PFAS accounted for about 50% of total PFAS in drinking water and 90% in serum. Urinary PFAS levels were very low compared with serum. PFBS showed the shortest half-life {average 44 d [95% confidence interval (CI): 37, 55 d]}, followed by PFHpA [62 d (95% CI: 51, 80 d)]. PFPeS and PFHpS showed average half-lives as 0.63 and 1.46 y, respectively. Branched PFOS isomers had average half-lives ranging from 1.05 to 1.26 y for different isomers. PFOA, PFHxS, and linear PFOS isomers showed average half-lives of 1.77, 2.87, and 2.93 y, respectively.DISCUSSION: A general pattern of increasing half-lives with increasing chain length was observed. Branched PFOS isomers had shorter half-lives than linear PFOS isomers. https://doi.org/10.1289/EHP6785.
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