Challenges to water quality assessment in Europe – Is there scope for improvement of the current Water Framework Directive bioassessment scheme in rivers?

The EU Water Framework Directive (WFD) assessment scheme has been putting in force the evaluation of freshwater ecosystems Europe, including a new paradigm ecological status. After almost 20 years since WFD implementation, it is imperative to evaluate efficiency its standard and explore possibility learning how improve effectiveness. That spirit this review, aiming (i) existing literature on bioassessment for assessing ecosystem health, particularly lotic (where most consolidated); (ii) document which paths are suggested by scientific community tackling current challenges. In specific arena bioassessment, we first identify major constraints full implementation rivers. Second, analyse retrospective Ecological Risk Assessment (ERA) as an approach supporting management actions that could inspire improvements scheme. Third, review advances debate complementary metrics protocols and/or feasibility outcome. Fourth, conceptual improved strategy presented. Our proposal essentially merges with ERA philosophy, proposing tiered increasing complexity spatial resolution, where expert judgement included surgically at all decision stages. This requires true integration chemical, ecotoxicological LoE quantitative estimation risks, provides comprehensive framework accommodates tools perspectives already other authors. Besides providing strengths weaknesses scheme, wish open way discussion towards health.