How many are the fears? In the Neolithic, great animals caused fear; using rocky artifacts, we learn to defend ourselves and hunt them. With the passing of time and the advance of Science, we learned that microorganisms could cause diseases, sometimes fatal. Vaccines and remedies then came to play the same role as prehistoric artifacts. Nowadays, it is known that molecules of pollutants, even smaller in size than microorganisms, can be lethal, depending on the concentration and toxicity of a given organism. This paper articulates facts and attempts to reveal how important it is to be prepared to deal with the causative agents of acute or chronic diseases and to understand the role of emerging contaminants in the world today and in the future, with a view to implementing strategies to remove them or-ideally-to eliminate them the environment. Based on the analysis of historical cases, it proposes a new attitude to the challenges imposed in the world today, by suggesting short, medium and long terms strategies to avoid contamination of important water resources and to improve people's living conditions.