Short chain PFAS: very persistent but maybe not so toxic or bioaccumulative - how can we make fair comparisons?

Research profile seminar

Per- and polyfluoroalkyl substances (PFAS) have long been used to impart durable water repellency (DWR) to textiles. With the recognition of the hazardousness of the so called long chain PFAS those are being phased out in large parts of the industry. In the SUPFES project (www.supfes.eu) the aim is to compare available alternatives to the long chain PFAS in DWR applications to allow for a sound substitution. The substitution methodology proposed has a holistic approach, considering both environmental and technical performance. The seminar will focus on how we can make fair comparations.

The substitution methodology proposed has a holistic approach, considering both environmental and technical performance. First results show that there are a number of viable alternatives to long-chain PFAS based DWR, but that improved environmental performance may lead to decrease in technical performance (Holmquist et al., 2016, Steffen Schellenberger, 2016, Holmquist, 2016). There were also clear indications that substitution may lead to problem shifting, reducing one environmental problem but increasing another, one example is that non-fluorinated alternatives may need to be washed more frequently or give the DWR a reduced life length. To assess the risk of problem shifting life cycle assessment (LCA) has been proposed as the relevant method and recent efforts have greatly improved the potential to include (eco)toxicity aspects of textile chemicals in LCA (Roos, 2016, Roos et al., 2017).

Basing work on these recent achievements, with the addition of new (eco)toxicity characterisation factors wherever needed, we are comparing alternatives to long-chain PFAS based DWRs by means of currently available and commonly used LCA methods. However, current life cycle impact assessment methods (e.g. USEtox) may not capture relevant effects of PFAS, which are extremely persistent but not always very toxic or bioaccumulative, as the ever increasing environmental accumulation may not be captured by the models.

As the next step we will assess to what extent current methods give relevant results when PFAS are being assessed. Based on our results we will make recommendations for improved methods in substitution assessments.