The EU’s recast of the Urban Wastewater Treatment Directive: analysis of the scientific basis for identifying the cosmetic industry’s contribution to the extended producer responsibility

According to the recast Urban Wastewater Treatment Directive (UWWTD, Directive 2024/3019), quaternary treatment shall be implemented in large wastewater treatment plants (WWTPs) to remove micropollutants, accompanied by an extended producer responsibility system to cover the associated costs. Based on the conclusions of a feasibility report (FR), which identified pharmaceuticals and cosmetics as main sources of micropollutants in wastewater, the costs shall mainly be covered by these two sectors. In the present work, the FR is analysed with regard to the used data, the applied methods, and the derived conclusions concerning the cosmetic industry’s contribution to the total load of micropollutants and the total toxic load in wastewater. Numerous and scientifically serious shortcomings of the FR were identified that invalidate its conclusions. The analyses made in the FR are based on a dataset, which includes substances that are readily biodegradable, and/or not hazardous to the environment or to human health, i.e., which are not within the scope of the UWWTD. The process of selection of WWTP influent concentrations for many substances lacks consistency and transparency, and it remains questionable whether the used concentration data are representative for actual concentrations in untreated wastewater in Europe. The total toxic load was derived using predicted no effect concentrations (PNECs), including PNECs based on ecotoxicity data estimated with quantitative structure–activity relationship models, which are associated with a high level of uncertainty. The contribution of different sectors to the total toxic load was only derived for WWTP influent, although a derivation for WWTP effluents prior to quaternary treatment would have been much more appropriate. In the simplistic approach used to allocate each substance to a single main usage sector, numerous substances were wrongly assigned to the cosmetics sector, although they are mainly or exclusively used in other sectors. Our re-estimation of the contribution of cosmetics to the total toxic load of wastewater correcting only the wrong allocation to sectors resulted in a contribution of 1.4–2.7%, demonstrating that the 26% stated in the FR are a considerable overestimation of the contribution of the cosmetic sector to the total toxic load of WWTP influents.