In a large-scale survey of the world’s rivers, researchers have found antibiotics in about two-thirds, according to ScienceNews.org. Environmental antibiotic pollution fuels the rise of drug resistance, a global public health threat that could make common diseases untreatable and kill 10 million people each year by 2050, the UN warns.
Researchers surveyed rivers in 72 countries in six continents, testing for levels of 14 widely used antibiotics. About two thirds of the sites tested positive for antibiotics. About 16 percent contained levels considered unsafe according to standards from the AMR Industry Alliance, a global industry group.
The standards are based on what level of antibiotics would either kill off bacteria and promote resistance, or destroy algae in the environment. At one site in Bangladesh, at the Kirtankhola River, concentrations were 300 times the safe level.
Many of the highest levels were found in Asia and Africa, but drug resistant microbes that evolve at one site can spread quickly with animals or human travelers. The researchers noted that sites in Europe and the Americas also contained concerning levels of antibiotics. In Europe, the highest concentrations were found in a tributary of the Danube in Austria. In North America, the most polluted site was in Iowa near animal farms.
The highest levels were found near wastewater treatment systems, waste and sewage dumps, and in politically tumultuous regions like the border of Israel and Palestine.
Trimethoprim, used to treat urinary tract infections, was most widespread, found at 307 of the 711 sites surveyed. Ciproflaxacin, used to treat bacterial infections, was found most frequently at dangerous levels.
The project was led by researchers at the University of York in England, including environmental chemist Alistair Boxall and John Wilkinson of the Department of Environment and Geography.
“I don’t think I was expecting the degree of concentrations that we saw. That was quite eye-opening,” Boxall said.
The team sent sampling kits to partners around the world, and samples were then frozen and sent back to the University of York for testing.
The researchers used Google Street View to learn that many of the contaminated sites were located near pharmaceutical plants, which they suggested could be releasing pollution into the water. In Asia and Africa, many sites showed buildup of garbage and sewage on riverbanks.
Antibiotic pollution kills off bacteria that often play a crucial role in local ecosystems, while leading those that survive to develop drug resistance, compounding a global public health crisis for humans.
According to Boxall:
“Solving the problem is going to be a mammoth challenge and will need investment in infrastructure for waste and wastewater treatment, tighter regulation and the cleaning up of already contaminated sites.”