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

With this Correction, we would like to improve the specificity in our per- and polyfluoroalkyl substances (PFASs) terminology. PFASs are either nondegradable or degrade to form nondegradable terminal degradation products, usually (although not always) the perfluoroalkyl or perfluoroalkyl(poly)ether acids (collectively termed PFAAs by Wang et al.¹). Our focus lies on the perfluoroalkyl acids, and it is those that are referred to in the published paper when the abbreviation PFAA is used. Our framework covers nonpolymeric and polymeric perfluoroalkane-sulfonyl-fluoride- (PASF-) and fluorotelomer-based PFASs. The polymeric substances included in the framework are the side-chain fluorinated polymers that are considered precursors to PFAAs. The nonpolymeric substances included in our framework are the low-molecular-weight precursors to PFAAs and the PFAAs themselves. The substances covered by our framework are summarized in Table 1 of the published paper. Fluoropolymers or perfluoropolyethers were not considered in our framework. For example, we would like to point out that in the statement that our LCIA framework can be applied to the “vast majority of PFASs on the market”, and elsewhere in the article, we were not considering fluoropolymers or perfluoropolyethers, which comprise a significant production volume fraction of the PFASs on the market. Consideration of the LCIA of a wider range of PFASs, including fluoropolymers and perfluoropolyethers, would be a valuable extension of our framework. Furthermore, in Section 3.3, it was stated that no emissions of PFASs were included in the commercial LCI data set. Whereas emissions of shorter chain perfluoroalkyl substances were included (with one to three carbon atoms), emissions of PFHxA and its precursors were not.

We would also like to clarify that f in eq 2 is a mass fraction, as the characterization factor (CF) is expressed per kilogram emitted. In Table 1, the transformation fraction is given as a molar yield, which is to be transformed into a mass yield. In footnote a in Table 1, this is described as the weight fraction of the primary pollutant that is made up of the PFAA. A clearer description would be that the quotient between the molar weights (M (g/mol)) of the precursor (the primary pollutant) and the PFAA is to be applied. Note that when the primary pollutant x is a side-chain fluorinated polymer, the M of the repeating unit is applied. This has been clarified in a corrected version of the Supporting Information (SI). In addition, the SI was made consistent with model calculations: Table S15 was updated to reflect the fact that LCI data for the DWR-treated drape are per square meter not per kg textile (correspondingly, the C6 copolymer amount per functional unit reported in the main paper (Section 3.3) should be 0.001 kg), Section S4.1.2 was updated with a corrected formula, Sections S5.1 and S5.3 were updated with the correct K_DOC, and Section S5.4 was updated with relevant information regarding PFOS.

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.est.0c03965.

• Background information and further details for the Methods and Results/Discussion sections (PDF)