What difference can drop-in substitution actually make? A life cycle assessment of alternative water repellent chemicals

Abstract

Per- and polyfluoroalkyl substances (PFASs) are used in durable water repellents (DWRs) on outdoor garments and manufacturers are currently phasing out hazardous PFASs. A critical question is: which alternatives should be chosen? The answer should depend on a holistic assessment, but the published inventory data and methodological guidance for assessing PFAS in products is slim and typically limited to hazard assessment. We aim to provide a holistic assessment of the potential environmental consequences of this phase out of DWRs, going beyond the more traditional hazard-focused substitution assessment to also include a broad life-cycle-based assessment of PFASs and their drop-in alternatives.In this study, potential environmental consequences of the phase out were evaluated by applying a life cycle assessment (LCA) to shell jackets with side-chain fluorinated polymer based (i.e., PFASs) or non-fluorinated alternative DWRs with the aim to support a substitution assessment. We demonstrated an innovative approach to impact assessment by inclusion of PFAS related fate and toxicity and invested effort towards contributing new primary inventory data by using a combination of industry dialogue and performance measurements from our larger project context.From a methodological point of view, this paper demonstrates the state-of-the-art in product LCA of persistent textile chemicals and identifies the current limits of this assessment approach. It also delivers new LCI data of use to other analysts. The LCA results in this paper suggest that jackets without PFASs are environmentally preferable. Potential problem shifting due to increased washing and reimpregnation of the jackets did not outweigh PFAS-related potential toxicity impacts as indicated by LCA results. Based on the results presented here, specific DWRs within the non-fluorinated DWR group could not be identified as preferable to others. This LCA does however provide a relevant starting point for more detailed studies on specific DWR systems and it supports moves to phase-out PFASs from non-essential DWR uses.