Xenia Trier

Xenia Trier

Associate Professor

My research focus on analytical chemistry supporting the risk governance of chemical pollutants, including the implementation of regulation. Of particular interest are chemicals with irreversible effects, such as persistent contaminants including Per- and polyfluorinated alkyl substances (PFAS) and surfactants, in environmental media, biota, humans and products.  My expertise is on targeted, suspect screening and non-targeted screening to detect known and emerging contaminants, by chromatography coupled to mass spectrometry.


A summary on the knowledge, uses, pollution, concerns and regulation on PFAS may be found in the EEA webriefing on PFAS from 2020. 


What is PFAS?
Per- and polyfluorinated alkyl substances (PFAS) is a large group of more than 5000 synthetic chemical substances, that are used in more than 200 use categories. PFAS include substances such as PFOS (perfluorooctane sulfonic acid) and PFOA (perfluorooctanoic acid).  PFAS are organic molecules where hydrogen (H) has been replaced fully or partially by fluorine (F), and must include at least one -CF2- unit. 

What are the characteristics of PFAS?
Because of the strong fluoro-carbon bond, PFAS are very resistent to heat and physical stresses, and the fluorocarbon chain does not react with other molecules. As a consequence, all PFAS either are or form persistent degradation products.  They also repel other molecules including water, oil and dirt. 


Where are PFAS used?
They are used in more than 200 use categories, across industry and in consumer products.  Main uses includes fluorinated plastics such as Teflon and rubbers (elastomers), paints, lubricants, buildig products, in pesticides and pharmaceuticals, in F-gases (used in refrigerants), and as coatings in consumer products in ranging from textiles, leather, stone, glass, sporting equipment, cosmetics and personal care products, food contact materials, dental floss and electronics including batteries. 

What is the concern about PFAS?
There are multiple lines of concern of PFAS including:
1. PFAS will due to their persistency accumulate either in the environment, or in biota and humans. As a result, and if uses from many sources continue, the concentrations will increase and at some point exceed so-called 'effect levels', i.e. the concentration at which health effects occur. 
2. PFAS are different and have various toxicological effects, including human health particularly for children (suppression of immune system functioning, increase in cholesterol, thyroid disease, endocrine disruption, testicular and kidney cancer), environmental health and earth system effects (e.g. climate change for F-gases, and some are ozone depletion substances).
3. Pollution of the environment is ubiquitos, and in the western hemisphere there is PFAS in the rain and in all the people. 
4. Costs of remediation of pollution is very high and sometimes not possible, in e.g. drinking water and in polluted soils.
5. Environmental injustice in that the burden of the pollution and effects often are transfered across space (between countries), time (across generations) and to people who have not benefitted economically or otherwise from using/producing the chemicals.


What are the exposure routes of PFAS?
The main human exposure routes are via food (fish, shell-fish, some eggs), drinking water (particularly in areas close to polluted sites), textiles/dust and personal care products. 

How can PFAS be measured?
Because PFAS is a large group of very varied substances, different methods also need to be applied to detect all PFAS.  Typical methods include: 
1) Liquid chromatography (LC) coupled to mass spectrometry (LC-MS) is typically used for the water soluble PFAS 
2) Gas chromatography coupled to mass spectrometry (GC-MS) is typically used for volatile PFAS in air
3) Supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) is typically used for the very water soluble (mobile) PFAS
4) Screening method such as Total organic fluoride (e.g. by EOF-CIC), Total Oxidizable Precursor Assay (TOPA), XRF or 19F NMR may typically be used to screen for a broader range of PFAS.


What is being done to limit PFAS pollution in Europe and nationally?
Several initiatives are implemented and are under preparation at the EU and at national levels, see e.g. the EU PFAS strategy (being part of the the Chemicals Strategy for Sustainability), ECHA and EFSA documents. A key focus is to manage PFAS as a class, because it will be practically impossible to manage one at a time, and to only allow for essential uses.  Five member states (Denmark, Sweden, Norway, Germany, and the Netherlands) have on Jan. 13th 2023 submitted a proposal to the European Chemicals Agency (ECHA) to restrict all uses of PFAS.  Member states may have additional regulation to restrict the uses of PFAS and to monitor their presence in the environment.  

Current research

My current research areas include analysis to support the risk governance of environmental contaminants such as per- and polyfluorinated alkyl substances (PFAS), and other contaminants analysed in our RAACE group.  This includes developing analytical methods to detect and investigate patterns of known and unknown PFAS, by liquid chromatography coupled to accurate mass spectrometry, by targeted, suspect and non targeted screening methods, and combination with chemometric tools. 
Currently, I lead the EU Horizon Europe project ARAGORN focussing on remediation of persistent contaminants in soil and ecological restoration, and a national project on environmental PFAS analyses.
I am an active member of the Global PFAS Science Panel, of the  European Norman Network on exchange of information on chemicals, and of the Danish Society of Analytical Chemistry. 
Futhermore I contribute to national, EU and international science-policy developments on the risk governance of chemicals, such as the EU Chemicals Strategy for Sustainability, with a focus on topics such as safe and sustainable by design, mixtures, persistent pollutants (such as PFAS), indicators and early warning systems. 

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