Can biochemical endpoints improve the sensitivity of the biomonitoring strategy using bioassays with standard species, for water quality evaluation?

The Water Framework Directive (WFD) was adopted in 2000 and is a common framework for water policy, management and protection in Europe. The WFD assesses specific parameters; however, it ignores indicators of ecosystem functioning and sub-individual performance. Reservoirs are strongly influenced by anthropogenic activities that promote their imbalance. Bioassays and biomarkers are useful tools to link the chemical, ecological and toxicological assessments in water quality assessments. These approaches can be complementary to WFD methodologies, allowing the detection of impacts on the ecosystem. This study evaluated if the biochemical parameters can improve the sensitivity of the biomonitoring strategy using bioassays with the standard species Daphnia magna, in the assessment of the ecological quality of water reservoirs. To this end, water samples of Portuguese reservoirs were analysed in three sampling periods (Autumn 2018 and Spring, Autumn 2019). In parallel, a physicochemical characterization of waters was performed. D. magna feeding rate assays were performed for 24 h. After exposure, metabolism, oxidative stress and lipid peroxidation biomarkers were evaluated. Feeding rate assays showed sensitivity to different reservoirs. Biomarkers showed a higher sensitivity and can therefore improve the sensitivity of the biomonitoring strategy using bioassays. Bioassays and biomarkers approach allowed to highlight potential sources of stress, more related to the quality of the seston than to chemical contamination. This work highlights the complementarity between bioassays and biomarkers to identify ecotoxicological effects of surface waters, and can be extremely useful, especially in cases where the biotic indices are difficult to establish, such as reservoirs.

Reconciling agriculture and stream restoration in Europe: A review relating to the EU Water Framework Directive.

Agriculture is widespread across the EU and has caused considerable impacts on freshwater ecosystems. To revert the degradation caused to streams and rivers, research and restoration efforts have been developed to recover ecosystem functions and services, with the European Water Framework Directive (WFD) playing a significant role in strengthening the progress. Analysing recent peer-reviewed European literature (2009-2016), this review explores 1) the conflicts and difficulties faced when restoring agriculturally impacted streams, 2) the aspects relevant to effectively reconcile agricultural land uses and healthy riverine ecosystems and 3) the effects and potential shortcomings of the first WFD management cycle. Our analysis reveals significant progress in restoration efforts, but it also demonstrates an urgent need for a higher number and detail of restoration projects reported in the peer-reviewed literature. The first WFD cycle ended in 2015 without reaching the goal of good ecological status in many European water-bodies. Addressing limitations reported in recent papers, including difficulties in stakeholder integration and importance of small headwater streams, is crucial. Analysing recent developments on stakeholder engagement through structured participatory processes will likely reduce perception discrepancies and increase stakeholder interest during the next WFD planning cycle. Despite an overall dominance of nutrient-related research, studies are spreading across many important topics (e.g. stakeholder management, land use conflicts, climate change effects), which may play an important role in guiding future policy. Our recommendations are important for the second WFD cycle because they 1) help secure the development and dissemination of science-based restoration strategies and 2) provide guidance for future research needs.