Residues of medicinal drugs in the water

It's well known that France is one of the world's biggest consumers of medicines for human therapeutic and diagnostic use, ranking 4th worldwide (after the USA, Japan and Germany) and first in Europe. In 2019, 4,000 active pharmaceutical ingredients were dispensed worldwide on prescription. Whether in pharmacies (with 2,400 active ingredients and 9,550 specialties) or in hospitals (2,150 active ingredients and 5,950 specialties), per-capita consumption in France is around 48 boxes on average per year, except that between 2004 and 2019, per-capita drug consumption fell by 16% in France, while it rose by 27% in Germany. However, the period of health crisis linked to Covid-19 has led to an increase in prescriptions and consumption of certain therapeutic classes, such as drugs for mental disorders, particularly anxiolytics, hypnotics and antidepressants. This increase probably reflects the significant psychological impact of the Covid-19 epidemic and its social, professional and economic consequences.

The need for treatment and the use of medicines are recognized in public health terms, with the development of medical sciences and therapeutics, but the scientific community is also concerned about the dissemination of components in the environment, particularly in water and aquatic environments. For ecological reasons, of course, but also in terms of the health of human populations, the dissemination of drug degradation products and their residues, through direct discharge at home (despite the existence of collection systems) or in healthcare establishments, by excretion in particular, is the subject of suspicion regarding the contamination of aquatic environments (ecotoxicology approach). Consequently, the presence of these residues in various ecological compartments, even in low doses, is likely to expose populations to substances for which health risk levels have yet to be fully assessed.

The issue of drug residues in water is all the more crucial as, on the one hand, so-called low-noise risks require a long follow-up period to reveal their potential effects (delayed effects) on human health; on the other hand, mixtures between residues, forming cocktails between drugs and with other micropollutants (e.g. pesticides) make health risk assessments even more complex.

In the first section, we present the origin of drug residues in water and effluents, according to use and type of discharge. The multiple and highly diversified origins of discharge sources (at home, in healthcare establishments, in laboratories, in production plants) make the task of upstream management of these residues in effluents more complex. The "outfall" approach (treatment and purification plants) is the one currently adopted to filter or neutralize these substances....