Predicted No-Effect Concentrations (PNECs) are concentration thresholds commonly derived in environmental risk assessment that should be protective of the whole ecosystem. They are based on ecotoxicity data and extrapolation factors based on data abundance, test duration (acute/chronic), and data quality/uncertainty 108 . For TFA, the lowest PNEC of 0.12 µg/L was derived by Xie et al. and was based on algae that were previously shown as the most sensitive trophic level. The PNEC of 0.12 µg/L was derived from a NOEC of 120 µg/L by using an uncertainty factor of 1000, chosen because of the scarcity of (eco)toxicity data in the peerreviewed literature and because extrapolation to the marine environment requires extra precaution (typically by a factor 10 compared to freshwater). The ECHA REACH dossier reports a freshwater PNEC of 560 µg/L and a marine water PNEC of 56 µg/L, both based on the algal study reporting the 72h ErC10 (EC10 based on growth rate) of 5600 µg/L . Almost all surface water median and/or mean concentrations from peer-review studies reported as post-2010 already exceed the precautionary PNEC of 0.12 µg/L as derived by Xie et al. (Table , Figure ), while the NOEC of 120 µg/L and ECHA's PNEC of 560 µg/L are exceeded by some recently detected maximum freshwater/surface water values . Among terrestrial organisms (ecotoxicity studies), only crop plants were tested for TFA toxicity.