ABSTRACT
SUMMARY: Discharge of chemical substances in aquatic ecosystems (rivers, lakes, oceans) may cause changes in biotic community structure and function; otherwise know as biotic integrity. Among the main effects of pollutants on aquatic organisms, the literature reports severe pathologies, behavioural problems, and species migration and disappearance. These effects not only alter the functioning of communities and ecosystems, but also mean the loss of irreplaceable heritage potentially useful to health and sustainable development. The conservation of biological diversity essentially demands the conservation in situ of natural ecosystems and habitats. The aim of this work was to carry out a synthesis of the literature on urban liquid effluents in view to highlighting their potential impact on aquatic ecosystems, and thus obtain better understanding of their consequences on the quantitative and qualitative degradation of water resources, especially regarding the loss of biodiversity. This work reported in this chapter has four main sections. In the first section is presented a physicochemical characterisation of urban waters. The second section describes the different mechanisms implemented in the treatment of urban waters. The third section presents the regulatory aspects intrinsically related to urban effluents. The fourth section is devoted to studying the impact of urban effluents on aquatic biodiversity. The “complete ecotoxicological approach” is used to present the acute and chronic effects of certain pollutants present in urban waters on aquatic organisms and food chains.
