Elsevier

Toxicology Letters

Volume 333, 15 October 2020, Pages 13-21
Toxicology Letters

Background contamination of perfluoralkyl substances in a Belgian general population

https://doi.org/10.1016/j.toxlet.2020.07.015Get rights and content

Highlights

  • 11 PFAS were measured in the serum of 242 adults from Liege, in Belgium.

  • Levels observed seemed to be similar or lower than those reported in other countries.

  • Half of the population contained PFOS and PFOA serum levels above the HBM-I values.

  • Age and gender were the main predictors of exposure.

  • Breastfeeding, eating fish and seafood, use of nail polish impacted the PFAS levels.

Abstract

The few Belgian studies on the human exposure to perfluoroalkyl substances (PFASs) have until now concerned the Northern part of Belgium (Flanders), while data related to Wallonia (South region) are missing. To fill this gap, 8 perfluorinated carboxylic acids and 3 perfluorinated alkyl sulfonates were measured in the serum of 242 adults (>18 years old) recruited in 2015 and living in the Province of Liege. Some multivariate regression models were also built with the PFAS levels and the participant’s answers to a questionnaire about their diet and lifestyle habits in order to identify some predictors of exposure. The results obtained showed that although PFAS levels observed in our population seemed to be similar or lower than those reported in other countries, and especially lower than in the Northern part of Belgium, half of the population showed PFOS and PFOA serum levels above the health guidance values set by the German HBM Commission. As expected, age and gender were the main covariates explaining the different PFAS serum levels between participants, while breastfeeding (for women), consumption of fish and seafood, consumption of rice, and use of nail polish seemed also to impact the PFAS body burden of our population. Nevertheless, the statistical models were poorly predictive suggesting that the main sources of exposure were not taken into account.

Introduction

Perfluoroalkyl substances (PFASs) are man-made chemicals that have been widely used since the mid-20th century in many industrial applications as well as in everyday life consumer products, due to their unique oil and water repellant properties as well as their high thermal and chemical stabilities. They have been employed among others as surfactants in cleaning agents or in firefighting foams, as surface protectors in carpet, textiles, upholstery, food packaging, and non-stick cookware (ATSDR, 2018; Kissa, 2001; Lindstrom et al., 2011). They have also been useful in the automotive and aerospace industries, in building construction, in personal care products, etc (OECD, 2006; Wang et al., 2013). Due to their persistence, their ubiquity in the environment and their health concerns, a phase out has been initiated from 2000 by some American industries (Renner, 2008), and subsequent restrictions were implemented mainly in United States (US EPA, 2015) followed few years later by the European countries (Schröter-Kermani et al., 2013). The impact of these production and use reductions on the human exposure was confirmed by the decreasing temporal trend of the serum levels from worldwide general populations reported from 2000 to 2010 for some PFASs, mainly perfluorooctane sulfonate (PFOS) and to a lesser extend perfluorooctanoic acid (PFOA), (Berg et al., 2014; Glynn et al., 2012; Kato et al., 2011; Schoeters et al., 2017; Schröter-Kermani et al., 2013; Toms et al., 2014; Yeung et al., 2013). Nevertheless in some countries (i.e. China) where PFASs are still used and produced (Li et al., 2017; Xie et al., 2013), higher PFAS serum levels would be expected compared to other populations which might be associated with several health effects such like a decline renal function, hepatotoxicity or hypertension (Bao et al., 2017; Nian et al., 2019; Wang et al., 2019).

There are different reasons why actual human biomonitoring focused on PFAS contamination is needed so far. Firstly, decrease of PFOS exposure related to the implementation of last regulations still deserves to be confirmed (i.e. inclusion of PFOS in the Annex B of the Stockholm Convention, inclusion of PFOA and other perfluorinated carboxylic acids on the candidate list of substances of very high concern within the European REACH program). Secondly, for other PFAS than PFOS and PFOA, the temporal trends of serum levels seemed to vary according to the perfluorinated chemicals, the time and the country where the study took place. For instance, upward trends have been reported for perfluorononanoic acid (PFNA), perfluorohexanesulfonate (PFHxS) and perfluorobutanesulfonate (PFBS) in Sweden between 1996 and 2010 (Glynn et al., 2012) or in United States between 1999 and 2008 (Kato et al., 2011), while no clear trend was observed for PFNA in Germany during the two last decades (Schröter-Kermani et al., 2013). Then, human contamination data concerning short chain PFAS such as PFBS, a recently used as an alternative of restricted PFASs (Wang et al., 2013) are still lacking. And finally, other fluorinated substances like fluorotelomers or functionalized perfluoropolyethers demonstrated to be potential precursor of PFOS and/or PFOA are until today not regulated (Wang et al., 2013).

In addition, if food intake and especially seafood product consumption was considered for a long time as the main contributor to the human exposure (Haug et al., 2011; Vestergren and Cousins, 2009), other food items and other routes of exposure have been demonstrated to substantially contribute to the total exposure (Bartolomé et al., 2017; Berg et al., 2014; de la Torre et al., 2019; D’Hollander et al., 2015; Fraser et al., 2012,2013; Klenow et al., 2013; Shoeib et al., 2011). For instance, the contribution of fruits to the total dietary intake could vary from 20 to 93 % depending on the PFAS considered, the country where the assessment was carried out, or the population targeted (adults or children) (D’Hollander et al., 2015). Inhalation or ingestion of house dust were estimated to represent from 1 to 13 % of the dietary exposure of PFAS, these percentages could even increase up to 50 % for toddlers (de la Torre et al., 2019; Shoeib et al., 2011). Definitely, the contributions of these currently known exposure routes have not been yet fully determined, would be country or region dependent, and would likely not account for the totality of the human exposure suggesting that other sources have not yet been clearly identified (Ericson et al., 2008; Ingelido et al., 2010; Jain, 2014; Kärrman et al., 2009; Kato et al., 2011). Thus further studies are needed to better characterize the current sources of exposure to PFASs and their contribution to the global exposure.

The PFAS exposure of the general population has been well documented since 2000′s but only a few dozen recent data on blood concentration in Europe, produced after 2010, are up to now available. In Belgium, Flanders (Northern part of Belgium) was one of the European pioneers by developing and implementing HBM programs since 2002. Indeed the Flemish Environment and Health Studies (FLESH) have covered 3 distinct time periods from 2002 and 2015, and have included more than 5800 participants (Reynders et al., 2017; Schoeters et al., 2017). Among the fifty hazardous chemicals included, PFASs were measured in different population categories in the 2 last campaigns (2007–2011 and 2012–2015) thus producing recent trends for these persistent organic pollutants in the Northern half of Belgium. The opposite situation is occurring in Wallonia (Southern part of Belgium) where the Walloon policy-makers are only beginning to invest in HBM to assess environment health and support policy actions. Nevertheless, few small-scale HBM studies were already locally carried out in Wallonia (Hoet et al., 2013; Koppen et al., 2019; Pirard et al., 2012, 2014,2018) but none were so far focused on PFASs.

Thus, the aims of the present study were to assess the background PFAS contamination in the general Walloon population, and to explore the contribution of food consumption and lifestyle habits as well as some demographic characteristics on the current PFAS exposure in Wallonia. For these purposes, serum samples collected during a previous study from 242 people older than 18 years old and living in the Province of Liege (Pirard et al., 2018) were analyzed for 8 perfluorinated carboxylic acids and 3 perfluorinated alkyl sulfonates, including short- and long-chain PFASs. The answers to the questionnaire related to food habits, life styles and home environment were also included in statistical models to identify some predictors of PFAS exposure.

Section snippets

Study participants

In 2015, 252 participants aged from 18 to 76 years and living in the Province of Liege were recruited through the Provincial High Schools and Provincial offices, to obtain a non-occupationally exposed population homogeneously distributed between gender, age classes (18–29, 30–39, 40–49, 50–59, >60 years), and the rural or urban character of their residence place. They signed an informed consent, provided a blood sample in clot activator tubes (without gel), and answered a questionnaire about

Levels of exposure

Among the PFASs monitored in the serum of our participants, PFBS, PFPeA, PFHxA, and PFDoA were never detected in any of the 242 samples. Although these compounds have usually been rarely positively measured in the general population (Cariou et al., 2015; Ericson et al., 2007; Kato et al., 2011; Lee et al., 2017; Long et al., 2015; Schröter-Kermani et al., 2013), the human exposure to PFBS, PFPeA and PFHxA was expected because these shorter-chain are used to replace long-chain PFASs as

Conclusion

The human background contamination of PFASs was measured for the first time in Wallonia (Southern part of Belgium) by determining the levels of 11 PFASs in 242 serum samples collected in 2015 from individuals living within the Province of Liege. For all participants, at least 4 PFASs were detected simultaneously, with levels close to those recently reported in other European or North American countries, but substantially lower than levels measured in the North of Belgium. However, only half of

Ethical approval

This protocol was approved by the Hospital Faculty Ethics Committee of the University of Liege (B707201422894).

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This study was financially supported by the Walloon Region as part of the grant 18/16857.

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