There is more than litter and microplastics polluting the world’s waterways.

Nearly half of all rivers on the planet are contaminated with pharmaceutical drugs, according to a new study.

Researchers found 23 active ingredients exceeding “safe” concentrations, including those in antidepressants, antihistamines, stimulants, benzos and pain relievers, in 43.5% of 1,052 individual samples taken from 104 countries.

Of 137 large sites where multiple samples were taken, 34.1% of them had at least one location where concentrations were “ecologically concerning”, the researchers wrote.

“Our results show that a very high proportion of rivers around the world are at risk from pharmaceutical pollution,” said study co-author Alejandra Bouzas-Monroy, a PhD student at the University of York in the UK. .

“We should therefore be doing much more to reduce emissions of these substances into the environment,” said Bouzas-Monroy, whose new report was published Wednesday in the journal Environmental Toxicology and Chemistry.

It’s “truly the first global assessment” of its kind, added Bouzas-Monroy, whose team analyzed samples littered from Europe, North America, Australia, Asia and Africa. .

According to the US Geological Survey, pharmaceuticals find their way into our rivers, lakes and streams in a variety of ways, including through waste discharged from pharmaceutical manufacturing facilities, as well as from farms, where livestock are routinely given medication to prevent illnesses and diseases, and people, who expel drugs that their body does not metabolize. (Obviously, flushing pills down the toilet is another unnecessary way humans contribute to the problem.)

The agency conducted its first major study on the subject in 2002, finding that seven or more different chemicals were present in at least half of the fluxes tested; 34% revealed 10 or more of these substances. In 2019, they also tested 1,120 wells and springs across the United States, where drugs like carbamazepine (an anticonvulsant), sulfamethoxazole (an antibiotic), meprobamate (a tranquilizer) and hydrocortisone (an antihistamine ) were among the most commonly found.

In 2008, The Associated Press conducted its own investigation of drinking water from 24 major metropolitan water suppliers and found traces of a variety of prescription drugs; Meanwhile, 34 other stations declined to participate in the AP survey because they do not routinely test for these chemicals in their own water supplies.

Scientists are unsure of the health consequences of long-term, low-level exposure to various drugs. Of course, the first victims are fish and other aquatic organisms, whose biological processes can be disrupted by large doses of drugs intended for humans.

Additionally, the overabundance of antibiotics in the environment has been a major concern among scientists who warn that it contributes to resistance to antimicrobials, aka ‘superbugs’.

“Overall, the results show that the API [active pharmaceutical ingredients] pollution is a global problem that likely negatively affects the health of the world’s rivers,” the researchers of the new global report concluded. “Work is urgently needed to resolve the issue and bring concentrations down to an acceptable level.”