An (Eco)Toxicity Life Cycle Impact Assessment Framework for Per- And Polyfluoroalkyl Substances

Area of Science:

• Environmental Science
• Life Cycle Assessment
• Chemical Risk Assessment

Background:

• Per- and polyfluoroalkyl substances (PFASs) are widely used industrial chemicals with unique properties due to their fluorinated chains.
• Existing life cycle impact assessment (LCIA) methods struggle to comprehensively characterize the diverse family of PFASs.
• PFASs can degrade into highly persistent perfluoroalkyl acids (PFAAs), posing long-term environmental risks.

Purpose of the Study:

• To propose a novel framework for characterizing PFASs within LCIA.
• To translate emissions of primary PFASs into their persistent PFAA degradation products.
• To calculate human toxicity and ecotoxicity characterization factors for key PFAAs.

Main Methods:

• Development of a framework incorporating transformation fractions to link PFAS emissions to PFAA formation.
• Adaptation of an LCIA model for PFAAs, calculating characterization factors for human toxicity and aquatic ecotoxicity.
• Evaluation of the model's ability to capture long-term fate, including oceanic accumulation, and uncertainty analysis.

Main Results:

• Characterization factors for perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA), and perfluorobutanesulfonic acid (PFBS) were calculated.
• These PFAAs rank in the top 5% for marine ecotoxicity among over 3000 chemicals in the USEtox database.
• Uncertainty analysis suggests similar high rankings for human health impacts; data availability is a key limitation.

Conclusions:

• The proposed framework effectively characterizes PFASs in LCIA, addressing their transformation into persistent PFAAs.
• PFASs, even at low emission levels, can significantly influence LCA outcomes due to their high toxicity and persistence.
• Further research is needed to improve data availability and reduce uncertainties in PFAS risk assessment.