Reviewing Biological Indices and Biomarkers Suitability to Analyze Human Impacts. Emergent Tools to Analyze Biological Status in Rivers

Abstract

The Catalan Water Agency has been testing and applying new methodologies and emergent tools over the last 20 years in order to enhance water quality monitoring in the Catalan River Basin District according to the EU Water Framework Directive (WFD) requirements. As a result the ecological quality of water bodies in Catalonia has been established and is currently monitored. Furthermore, bioremediation strategies are being implemented to improve the ecological quality of several water bodies. In relation to this the Catalan Water Agency is also devoted to assess and report to the EU that the applied remediation actions improved the quality of those water bodies. Most Mediterranean rivers suffer from water scarcity, and they are often located in densely populated areas. The combination of overpopulation with water scarcity translates into an overexploitation of water resources and consequently the deterioration of the ecological quality of rivers. Such deterioration in many places affects both the riparian habitat and water quality. Deterioration of water quality includes the reduction of water flow and the increase of pollution. Indeed in many occasions natural water flow is so low that effluents from wastewater treatment plants (WWTP) enter into the river with little dilution. Accordingly Mediterranean rivers are contaminated not only with persistent pollutants such as metals or persistent organic contaminants but also by pesticides, pharmaceuticals, personal care products, and other substances that, although they are not persistent, are continuously released into rivers from both diffuse sources and WWTP effluents. When this happens, the use of biomarkers and of laboratory or field toxicity assays offers the possibility to detect small changes in water quality, to identify detrimental stressors affecting aquatic biota, and to detect specific subtle effects such as those caused by endocrine disrupters. This chapter is structured in three main subchapters that address the suitability of biomarkers, in situ bioassays, and omic responses to assess effects of pollutants in river biota from Catalonian rivers.