Many of the world's rivers are polluted with antibiotics
Rivers around the world contain antibiotics at concentrations exceeding safe levels. This conclusion was reached by an international group of environmentalists after thoroughly monitoring river water in 71 countries. Antibiotic contamination of river water is a major factor in the spread of bacterial resistance to these medications.
The study's results were presented at the annual European conference of SETAC (Society for Environmental Toxicology and Chemistry) in Helsinki. Scientists analyzed 711 river water samples from 71 countries. Antibiotics were detected in 65% of the samples, and other medications in 50-80%. In rivers in Austria, Belgium, Iraq, Pakistan, Nigeria, and Laos, the concentration of at least one antibiotic in river water was above the Predicted No Effect Concentration (PNEC).
The highest antibiotic contamination was found in rivers in Asia and Africa. In Pakistan's Ravi River, scientists discovered a mixture of seven antibiotics in a total concentration of over 3 mg/L. Other samples from Pakistani rivers contained 33 medications, including antibiotics. The antibiotic ciprofloxacin was detected in 55% of samples from African rivers.
The Danube was found to be the dirtiest river in Europe. Researchers found seven antibiotics, including clarithromycin, in water samples taken in Austria. Five antibiotics were detected in the Thames (UK) and its tributaries, including ciprofloxacin, at concentrations three times higher than the PNEC.
Today, the role of the environment in the spread of antibiotic resistance is no longer in doubt. Pathogenic bacteria acquire antibiotic resistance genes from various sources, including environmental microorganisms, such as those in soil or water. Therefore, antibiotic pollution of rivers may be a significant factor contributing to the development of resistant bacterial strains.
Agriculture is the main source of antimicrobials in the environment. The WHO is already calling on farmers to reduce antibiotic use in livestock production, but this will take a long time to happen in developing countries.