The European Water Framework Directive (WFD) represents a transformation of the guidelines for water quality assessment and monitoring across all EU Member States. At present, it is widely accepted that the WFD requires holistic and multidisciplinary ecological approaches by integrating multiple lines of evidence. Within the scope of the WFD, the scientific community identified clear opportunities to take advantage of an ecotoxicological line of evidence. In this context, ecotoxicological tools, namely biomarkers and bioassays, were proposed to contribute to the integration of the chemical and biological indicators, and thus to provide an overall insight into the quality of a water body. More than one decade after the publication of the WFD, we reviewed the studies that have attempted to integrate ecotoxicological tools in the assessment of surface water bodies. For this purpose, we reviewed studies providing an ecological water status assessment through more conventional community based approaches, in which biomarkers and/or bioassays were also applied to complement the evaluation (Table 1).
From the literature review it emerges that investigations at community level appear suitable for the assessment of ecological quality, whereas bioassays/biomarkers appear to be specially useful to investigate the causes of ecological impairment, allowing a better understanding of the cause–effect-relationships and to work as early warning, rapid evaluation and cost effectiveness systems of ecosystem disturbance. In this sense, community level responses and ecotoxicological approaches seem to be complementary reinforcing the need to use combined approaches of different disciplines in order to achieve the best evaluation of the ecosystem community health.
The European regulatory authorities are presently in the phase of implementing the WFD all over Europe, and results will be assessed in the next few years, which will eventually lead to the introduction of improvements and changes in the Directive. It might then become pertinent to stand for the combined/complementary use of ecological indices, biomarkers, and bioassays in assessing ecological quality status. Further research will improve current knowledge and allow methodological and data analysis harmonization, aiming at generalization to other assessment and classification schemes worldwide.
This study is published in:
Monica Martinez-Haro, Ricardo Beiras, Juan Bellas, Ricardo Capela, João Pedro Coelho, Isabel Lopes, Matilde Moreira-Santos, Armanda Maria Reis-Henriques, Rui Ribeiro, M. Miguel Santos, João Carlos Marques (2015) A review on the ecological quality status assessment in aquatic systems using community based indicators and ecotoxicological tools: what might be the added value of their combination? Ecological Indicators 48, 8-16 (link)