Contraceptive pills, antidepressants, antibiotics, anticancer drugs, drugs… The list of drugs found in rivers is long. And at concentrations that are far from negligible.
A study revealed in 2021 that, of more than 1,000 samples taken from rivers in around 100 countries, 43% showed the presence of at least one drug whose concentration was considered to be of concern for ecosystems.
The most common medications found were carbamazepine (a medication used to treat epilepsy), metformin (a medication for type 2 diabetes), and caffeine.
In an article published on June 5 in Nature Sustainability, an international team of researchers is sounding the alarm.
“When we think about water pollution, we visualize oil spills, plastic bags in the ocean… But we don’t see chemical pollution,” illustrates Michael Bertram, one of the authors, who is also a professor at the Swedish University of Agricultural Sciences.
Numerous studies have reported that male fish, downstream from sites where wastewater is discharged by municipalities, had undergone feminization of their reproductive organs due to the presence of estrogens in them. Another showed that fish exposed to antidepressants lost their reflexes to flee or play dead from a predator.
This can lead to a drastic drop in certain populations and, through a domino effect, ecosystems find themselves severely disrupted.
A first solution that could be considered would be to improve wastewater treatment. Because when you swallow a medication, a large part is not assimilated by the body and ends up directly in the toilet.
However, very often, water treatment plants are not equipped to filter these medications. “Typically, only the solids are removed before the wastewater is released into waterways,” explains Michael Bertram. And yet, according to a 2017 UNESCO report, 80% of the world’s wastewater is released without even being treated first.
The European Parliament also adopted a text at the beginning of April requiring the pharmaceutical and cosmetic industries to cover 80% of the costs of modernizing wastewater treatment plants to eliminate micropollutants from wastewater, according to a “polluter pays” principle.
For Michael Bertram, beyond wastewater treatment, the pharmaceutical industry should address the problem at its source and turn to more sustainable solutions. Indeed, medications currently available in pharmacies can often have effects on ecosystems, even at very low doses.
We could consider “greener” molecules, which would degrade quickly once in the environment, thus minimizing their impact. These alternative options could be offered in pharmacies, in the same way that “GMO-free” or “pesticide-free” foods are available in supermarkets today, for example.
For Valérie Langlois, professor at the National Institute of Scientific Research (INRS), this problem is not new, but it is getting worse.
The idea of green chemistry is good, according to her, but requires time. “You shouldn’t just go for molecular design or water treatment solutions,” she says. She indicates that we could, for example, look for solutions to reduce anxiety and, thus, limit the number of prescriptions.
The problem is even broader than the pharmaceutical industry: microplastics, PFAS and pesticides are found in rivers, among other things. “It’s a Pandora’s box,” she sighs. “We really need to tackle all fronts at once. »
