Intraindividuell trend av PFAS bland kvinnor och barn

• I den här studien undersöktes hur serumhalterna av PFOA, PFNA, PFDA, PFUnDA, PFHxS (linjär och grenade) och PFOS (linjär och grenade) förändrats hos unga kvinnor och deras förstfödda barn (POPUP-kohorten) under en 12-årsperiod av upprepade provtagningar (2-4 gånger). Två grupper av mammor provtogs för första gången tre veckor efter förlossningen. De som provtogs första gången 1996-99 följdes upp en gång efter 12 år (N=57) och de som lämnade första provet 2004-2011 följdes upp 2-3 gånger 4-12 år senare (N=13-44). Under åren 1996-99 provtogs spädbarn vid 3 månaders ålder och följdes upp 12 år senare (N=31). Under åren 2008-2015 togs första provet på barnen när de fyllt 4 år eller 8 år. 4-åringarna följdes upp vid 8 år (N=34) eller vid 8 och 12 års ålder (N=11) och 8-åringarna följdes upp vid 12 års ålder (N=34). De intra-individuella PFAS-trenderna, bland både mammor och deras barn, verkar generellt ha påverkats av de åtgärder som vidtagits för att begränsa tillverkning/användning av ämnena under de senaste årtiondena. Utfasning/förbud av PFOA och PFOS, med start runt 2000, bidrog till i medeltal sjunkande intra-individuella serumhalter med ökande ålder både hos mammor och barn. Åtgärder för att begränsa produktion/användning av PFNA, PFDA och PFUnDA kom senare än för PFOS och PFOA. Det resulterade i ökade intra-individuella serumhalter mellan första provet (1996-199) och provet 12 år senare bland både mammor och barn. För deltagare med första provtagning senare under studieperioden, 2004-2011 för mammor och 2008-2015 för barn, observerades en tendens av i medeltal sjunkande halter med ökande ålder. Undantag var PFNA and PFUnDA hos mammorna, för vilka något ökande eller stabila halter observerades. Bland mammorna provtagna första gången 1996-1999, sågs i medeltal en ökning av intra-individuella PFHxS-halter under 12-årsperioden, troligtvis på grund av de dricksvattenföroreningar av PFAS som förekommit i Uppsala. Bland barnen observerades dock ingen skillnad mellan första provtagningen vid 3 månaders ålder och 12 år senare. Bland mammorna som provtogs för första gången 2004-2011, tycks ökningen ha följts av en minskning efter att rening av PFAS från Uppsalas dricksvatten infördes 2012. En minskning av intra-individuella PFHxS-halter observerades också hos barnen mot slutet av studieperioden. Bland mammorna kan skillnader i intra-individuella PFAS-trender mellan deltagare sannolikt till viss del förklaras av hur många barn kvinnorna fött under uppföljningsperioden, eftersom elimineringen av PFAS ur kroppen ökar under graviditet, förlossning och amning.

• This report describes how the serum concentrations of highly fluorinated substances (PFASs) have changed among young women and their children (POPUP cohort) who have been sampled repeatedly over a 12-year period. In a cohort of first-time mothers recruited in 1996-1999 and 2004-2011 and their first-born children from Uppsala (POPUP), PFOA, PFNA, PFDA, PFUnDA, PFHxS (linear and branched) and PFOS (linear and branched) were studied. The mothers, who were first sampled 3 weeks after delivery of their first child in 1996-99, were only followed up once after 12 years. This was also true for their 3 month old first-born babies. Starting in 2004, the mothers were followed up 4, 8 and 12 years after the first sampling 3 weeks after delivery, and their children were sampled at 4, 8 and 12 years of age (no 3-month-sampling) starting in 2008.Among the mothers, serum concentrations of individual PFASs were in most cases significantly correlated (p≤0.05) between sampling occasions, with Spearman's correlation coefficients (r) of 0.14-0.91 (N = 14-71). The strongest correlations were observed 4-12 years after delivery. Among the children, who were first sampled 1996-1999 at 3 months of age and then followed up with a sampling at 12 years of age (N = 31), no significant correlations were observed (r = -0.14-0.35, p> 0.05). The correlations between PFASs in samples 4, 8 and 12 years after birth (N = 14-36), on the other hand, were significant in many cases (r = 0.28-0.81).Differences in intra-individual trends were observed between the participating mothers and may depend, among other things, on how many children the mothers gave birth to during the follow-up. PFAS concentrations decreased by an average of 30-50% per child born during follow-up (not for PFUnDA). This is probably due to an increased elimination of PFASs linked to pregnancy, childbirth and breastfeeding.Despite these individual differences in intra-individual trends of specific PFASs, some general conclusions could be made about intra-individual trend patterns for different PFASs. Among mothers who were sampled for the first time in 1996-1999, and then followed up with a sampling 12 years later, the PFOA and branched/linear PFOS concentrations on average decreased with increasing age, while concentrations of PFNA, PFDA, PFUnDA and branched/linear PFHxS increased. Among mothers with initial sampling starting in 2004, PFOA and PFOS concentrations on average still decreased with increasing age 4-12 years after the initial sampling, while PFDA initially decreased and thereafter stabilized at lower levels. This suggests that intra-individual cumulative PFOA and PFOS exposure was lower than cumulative elimination from the body throughout most of the follow-up period (decreasing serum levels), whereas the differences between exposure and elimination of PFDA decreased towards an equilibrium at the end of follow-up. When initial sampling started in 2004, PFNA levels were on average unchanged with increasing age, while PFUnDA levels increased towards a plateau at the end of the 12 year follow-up. For PFHxS, the concentrations seemed to decrease with increasing age towards the end of the follow-up. The homologue-specific differences in intra-individual trends may be due to differences in timing of international measures to limit production/use of the studied PFASs. Actions against PFNA, PFDA and PFUnDA came later (end of the 2000s-beginning of 2010s) than for PFOS and PFOA (beginning-middle of the 2000s). The special case of drinking water PFHxS contamination in Uppsala, with remediation in 2012, most probably also contributed to the observed PFHxS intra-individual trends.Among the first-born children, decreasing PFOA and PFOS concentrations were in general observed throughout the follow-up from 3 months to 12 years of age. The PFHxS concentrations on average did not differ between the samples taken at 3 months of age (start 1996-1999) and 12 years later. Among children with first sampling at 4 years of age, with first sampling starting 2008-2015, slightly declining concentrations were observed with increasing age. PFNA, PFDA and PFUnDA concentrations increased with age among children sampled at 3 months of age 1996-99 and 12 years later. However, among children sampled for the first time at 4 years of age starting in 2008-2015, intra-individual concentrations of PFNA and PFDA decreased slightly up to 12 years of age. PFUnDA also seemed to decrease slightly on average after an initial period of increasing/stable levels. Taken together, the results strongly suggests that the intra-individual trends of the PFASs, studied in both mothers and their children, were influenced by the measures taken to limit PFAS production and use in recent decades. Phasing out of PFOA and PFOS during the 2000s has generally contributed to declining serum levels with increasing age in both mothers and children. Measures to limit PFNA, PFDA and PFUnDA production/use came later than for PFOS and PFOA, which resulted in a combination of increasing serum concentrations with increasing age at the beginning of the follow-up, followed by a flattening/decrease during the latter part. The tendency of an age-dependent increase in PFHxS concentrations among mothers, and to some extent also in their children, were followed by a reduction of concentrations, on average, after the pollution of Uppsala's drinking water were remediated in 2012.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

Nyckelord

PFAS

blodserum

dricksvatten

exponering

kvinnor

barn

upprepade mätningar

Sverige

Nationell miljöövervakning

National

Health

Hälsorelaterad miljöövervakning

A Non-Toxic Environment

Giftfri miljö

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)