Budapest, Hungary – A wide-ranging global study has identified the Danube as the river with the highest concentration of antibiotics in Europe and the single most polluted on the continent.
Earlier this week, a team led by the University of York unveiled the findings of a massive international study, the first of this scale, that assesses the antibiotic pollution of rivers and waterways across the world – including the Seine, Thames, Mekong, Tiber and Danube.
The team presented their findings during the annual meeting in Helsinki, Finland, of the Society of Environmental Toxicology and Chemistry (SETAC), an environmental NGO and think tank with offices in Europe and the U.S.
65% of monitored sites in the world polluted with antibiotics
In order to spotlight the role played by waterways in the strengthening antibiotic resistance of environmental bacteria, which poses a significant threat to public health, researchers tested more than 700 sites in 72 different countries around the world to determine the concentration of 14 commonly-used antibiotics.
According to their results, 65% of the monitored sites had antibiotics in them, with a concentration sometimes exceeding, like in the case of Bangladesh, safe levels by up to 300 times.
Detected in nearly half of the sites, trimethoprim, which is primarily used to treat urinary tract infections, was the most commonly-found antibiotic. And although the highest concentration of antibiotics were found in Asia and Africa (including Bangladesh, Kenya, Ghana, Pakistan and Nigeria), rivers in North America and Europe also reported alarming concentration rates at some monitored sites.
Danube is most contaminated river in Europe
According to this study, the Danube is the most polluted river with antibiotics in Europe. After taking samples from a Danubian sites in Austria, researchers found traces of up to seven antibiotics surpassing the safety threshold.
The second longest river in Europe after the Volga, the Danube has a length of more than 2.800 kilometers and runs from Germany through nine other Central and Eastern European countries (Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine) before ending in the Black Sea. It also runs through a number of major capitals in the region, including Vienna, Bratislava, Budapest and Belgrade.
A “widespread contamination” of rivers around the world
“The results are quite eye-opening and worrying, demonstrating the widespread contamination of river systems around the world with antibiotic compounds”, Professor Alistair Boxall, from the York Environmental Sustainability Institute, said.
He added: “Many scientists and policy-makers now recognize the role of the natural environment in the antimicrobial resistance problem. Our data show that antibiotic contamination of rivers could be an important contributor”.
According to the study, the sites most at risk of antibiotic pollution were located in the vicinity of wastewater treatment systems and sewage dumps.