Commentary on the EU Commission's proposal for amending the Water Framework Directive, the Groundwater Directive, and the Directive on Environmental Quality Standards

Abstract The EU Commission published on the 26th of October 2022 its proposal for amending three central water management Directives, the Water Framework Directive, the Groundwater Directive, and the Directive on Environmental Quality Standards. The proposal introduces a series of amendments and changes to remedy shortcomings that were identified in the previous fitness check of the European water legislation and to align the legal framework with the scientific and technical progress of the last decades. This commentary briefly summarizes and evaluates the new elements that are most relevant from a toxicological and ecotoxicological perspective. The Commission proposal substantially extends the list of WFD priority substances and now includes 68 substances and substance groups. It also identifies five substances and substance groups as a priority for groundwater management. In several instances, generic sum-EQS values are suggested for selected substance groups, an approach that lacks scientific underpinning and might not always be sufficiently protective. EQS values for substances groups are certainly needed, but are better set using relative potency factors or other implementations of the Concentration Addition concept. The Commission proposal employs this approach for setting groupwise EQS values for PFAS chemicals and PAHs and it should be systematically applied also to other groups of priority substances. Effect-based methods (EBMs) are now included in the legal text of the WFD, which is highly welcome. However, the Commission proposal limits EBMs to explorative studies and does not include the setting of EQS values based on EBM-methods. Revising the major legislative frameworks offers opportunities to streamline water pollution management in the spirit of the “one substance, one assessment” idea. Further details on how substance evaluations performed in the context of water management can be harmonized with those performed by EFSA, ECHA and EMA during substance registration and authorization would have been welcome.