There are everywhere. Fortunately in very low concentrations. "Professor Yves Levi, a toxicologist at the University Paris XI, do not hesitate to speak of a taboo subject in the world of the hexagonal public health: pharmaceutical residues in city water. This theme was at the heart of the symposium coming together in Berlin European to a new discipline: the study of emerging contaminants in drinking water systems.
A subject of particular concern these experts: endocrine disruptors to chemical or pharmaceutical origin. Some of these micro-pollutants have an action on animal or human hormonal mechanisms. This is the case of antibiotics, found in wastewater at very low dosages (between the NanoGram and microgram per litre). "The majority comes from the consumption of drugs in the home," said Yves Levi.
In fact, drugs are very poorly absorbed by the body. When following antibiotic therapy, only 10 of the active ingredient is actually set in the body. The remaining share in the toilet. Used to prevent bacterial infections, antibiotics are also heavily used to increase the rate of growth of livestock (between 3 and 7).
Other active substances dispersed in nature. "We found a high concentration of diclofenac in Swiss rivers," reported Hansruedi Siegrist, researcher at the Swiss Federal Research Centre on water (Eawag). Anticontraceptifs patches from compounds, suspected change of sex of fishes, are very present in wastewater discharges. "Most of these compounds degrade naturally over time", reassures Hansruedi Siegrist.
Tighten the regulatory
Should we worry about these results For many experts, "a hardening of the regulation is inevitable." In practice, the extent of the long-term risk of regular exposure to very low concentrations of products is complex and is the subject of numerous controversies. The analysis of the multiple possible combinations is even more delicate. "More than 2,500 chemical substances are approved as drugs in Germany." "It must be complementary studies", note Hermann Dieter, specialist of organic pollutants in the German Ministry of the environment. "It is very difficult to make the link with human health." Some fish change sex spontaneously in nature. "Should new biological assays", complete Yves Levi. Martin Jekel, of the University of Berlin, said that "drug consumption will increase with the ageing of the population and the need to eliminate the most toxic components. According to these experts, the pharmaceutical industry should commit to the improvement of the metabolism of the drug by the body.
In this context, the water treatment industry say "ready to intervene" by appealing to higher-performance filtration processes. At Veolia Environnement, Michel Dutang, Director of technology development, is expected to a growing demand of scientific expertise from the public services in charge of the surveillance of drinking water. "Our business becomes more and more technology", he summarizes.
To ensure its rear, the French group has signed agreements with research centres specialized in large cities such as Berlin. Most of the time, these public-private partnerships are a prerequisite for the signing of contracts for water treatment. "Each centre includes about thirty people and costs between 5 and 6 million EUR per year," said Michel Dutang, who believes hard as iron science and economy are made to agree. A philosophy which perhaps earned him his recent appointment to the High Council of science and technology (HCST) attached to the Prime Minister.