From the Thames to the Tigris, many of the world's largest rivers are hosts of antibiotic waste, according to a global study by researchers from the University of York.
The body of water long immortalized in Johann Strauss II's famous Blue Danube Waltz received an edgy new superlative on Monday: Along with being Europe's second-longest river, the Danube is now the continent's most drug-polluted.
Rivers from the Thames in England to the Tigris in Iraq host concentrations of antibiotics exceeding safe levels by up to 300 times, which could play a role in human drug resistance, according to the first international study of its kind presented on Monday.
Scientists from the University of York in England tested for 14 commonly used antibiotics in rivers in 72 countries. They found antibiotics at 65 percent of the surveyed sites, causing scientists and policy makers to recognize the role of the natural environment in the antimicrobial resistance problem, according to Professor Alistair Boxall, Theme Leader of the York Environmental Sustainability Institute.
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The World Health Organization classifies antibiotic resistance, or the increasing ineffectiveness of antibiotics, as "one of the biggest threats to global health, food security, and development today.”
The UN declared it a national emergency last year, warning that over 10 million people could die as a result of resistance by 2050, outnumbering the amount of deaths due to cancer, and around 24 million people could be forced out of their homes by 2030.
Resistance is a naturally occurring process that can be hastened by improper use of the medicines, according to the organization. This includes improper waste disposal methods, overuse by physicians and misuse in agriculture. It currently kills around 700,000 people per year, according to the UN.
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"Antimicrobial compounds from households, hospitals, pharmaceutical facilities and agricultural run-off released into the environment, combined with direct contact between natural bacterial communities and discharged resistant bacteria, is driving bacterial evolution and the emergence of more resistant strains," a UN report on antibiotic resistance said.
When bacteria grow resistant to antibiotics, the medications do not work for the patients, causing infections and diseases to persist.
The latest study marks the first time many of the respective rivers have been systematically tested for a large number of antibiotics. The concentrations of drugs could contribute to antibiotic resistance, the researchers fear.
"Until now, the majority of environmental monitoring work for antibiotics has been done in Europe, North America and in China, often on only a handful of antibiotics," Dr. John Wilkinson, from the York University Department of Environment and Geography said. "We know very little about the scale of problem globally,”
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Trimethoprim, an antibiotic used to treat urinary tract infections, was found most frequently at 307 of the 711 sites, while Metronidazole, which is used to treat skin and mouth infections, was found to be the least safe.
Ciprofloxacin, which treats bacterial infections, was found to exceed safe levels most often.
Bangladesh, Kenya, Ghana, Pakistan and Nigeria hosted the highest concentration of unsafe sites, which were often in the vicinity of wastewater treatment systems and waste and sewage dumps, researchers found. They also found higher concentrations in areas of political unrest, such as the Israeli-Palestinian border.
In Europe, the most hazardous site was found on the Danube in Austria.
Both Boxall and the UN are calling for stricter regulations on antibiotic waste disposal.