A survey of 165 rivers finds unsafe levels of antibiotics at one in six sites tested. Such pollution can leave germs resistant (unharmed) by the drugs.
Antibiotics taint two out of every three rivers sampled as part of a big new survey. Scientists made the finding while testing water from 165 rivers across 72 countries. Many of most polluted sites were in Asia and Africa. Until now, there had been little testing in these areas for drugs in water.
The new data are a big concern. Bacteria that can’t be killed by antibiotics pose a large and growing threat to health. Doctors call these bacteria “superbugs.” As microbes encounter drugs in the environment, many will evolve changes. Called mutations, some of these may allow the germs to survive the drugs. Later, people infected with those microbes may find themselves at risk of life-threatening disease.
It doesn’t matter that some of these pollution problems are occurring in far-off sites around the world. People should still be as concerned about resistance evolving in these places as they are about it developing in their own backyards, says William Gaze. He’s a microbial ecologist in England who works at the University of Exeter Medical School. Even if wealthy countries wipe out antibiotic pollution, drug-resistant microbes can hitch a ride to those countries. They can arrive with sick travelers. They might move around the world in migrating birds. They might even arrive in imports of animal-based foods, says Gaze. “It’s a global problem,” says this scientist, who was not involved with the new survey. That’s why, he adds, “We need global solutions.”
Alistair Boxall and John Wilkinson work in England at the University of York. Together, they tested water from 711 sites. And 470 of them contained at least one antibiotic.
Explainer: Where antibiotics came from
About one in every seven of the sites tested — 111 in all — contained unsafe levels of the drugs. That judgment is based on guidelines by the AMR Industry Alliance. It’s a global group of biotech and drug companies. It has set safety thresholds. And those are based on data showing what levels of a drug would neither kill algae nor promote drug resistance in bacteria.
“I don’t think I was expecting the degree of [high] concentrations that we saw,” says Boxall, who is an environmental chemist. “That was quite eye-opening.”
He and Wilkinson shared their findings in a pair of papers presented on May 27 and May 28. 2019. They spoke in Helsinki, Finland at a meeting of the Society of Environmental Toxicology and Chemistry.
A survey of 165 rivers finds unsafe levels of antibiotics at one in six sites tested. Such pollution can leave germs resistant (unharmed) by the drugs.
Antibiotics taint two out of every three rivers sampled as part of a big new survey. Scientists made the finding while testing water from 165 rivers across 72 countries. Many of most polluted sites were in Asia and Africa. Until now, there had been little testing in these areas for drugs in water.
The new data are a big concern. Bacteria that can’t be killed by antibiotics pose a large and growing threat to health. Doctors call these bacteria “superbugs.” As microbes encounter drugs in the environment, many will evolve changes. Called mutations, some of these may allow the germs to survive the drugs. Later, people infected with those microbes may find themselves at risk of life-threatening disease.
Superbugs: A silent health emergency
It doesn’t matter that some of these pollution problems are occurring in far-off sites around the world. People should still be as concerned about resistance evolving in these places as they are about it developing in their own backyards, says William Gaze. He’s a microbial ecologist in England who works at the University of Exeter Medical School. Even if wealthy countries wipe out antibiotic pollution, drug-resistant microbes can hitch a ride to those countries. They can arrive with sick travelers. They might move around the world in migrating birds. They might even arrive in imports of animal-based foods, says Gaze. “It’s a global problem,” says this scientist, who was not involved with the new survey. That’s why, he adds, “We need global solutions.”
Alistair Boxall and John Wilkinson work in England at the University of York. Together, they tested water from 711 sites. And 470 of them contained at least one antibiotic.
Explainer: Where antibiotics came from
About one in every seven of the sites tested — 111 in all — contained unsafe levels of the drugs. That judgment is based on guidelines by the AMR Industry Alliance. It’s a global group of biotech and drug companies. It has set safety thresholds. And those are based on data showing what levels of a drug would neither kill algae nor promote drug resistance in bacteria.
“I don’t think I was expecting the degree of [high] concentrations that we saw,” says Boxall, who is an environmental chemist. “That was quite eye-opening.”
He and Wilkinson shared their findings in a pair of papers presented on May 27 and May 28. They spoke in Helsinki, Finland at a meeting of the Society of Environmental Toxicology and Chemistry.
More wide-ranging survey than ever before
No survey of drugs in water has ever been carried out on this scale, Boxall says. Earlier ones had focused on rivers in North America, Europe and China. In contrast, he and Wilkinson sent water-collection kits to colleagues all over the world. Then they tested the water they got back for 61 drugs. These included the 14 antibiotics.
Samples continue to roll in and the researchers plan to release more data in the future. “Ultimately, it would be nice if we could get samples from every country of the world,” Boxall says.
Many sites with unsafe levels of the drugs contained more than one antibiotic. The most commonly found one was trimethoprim (Try-METH-oh-prim). It’s used to treat urinary-tract infections. And it showed up at more than four out of every 10 sites sampled. Other commonly found antibiotics were sulfamethoxazole (Sul-fa-meh-THOX-uh-zole), ciprofloxacin (Cih-pro-FLOX-uh-sin) and metronidazole (Meh-troh-NY-duh-zole).
The Kirtankhola River, near the south-central city of Barisal, Bangladesh, contained the highest antibiotic level of any site. Metronidazole levels there approached 40,000 nanograms per liter. That’s roughly 300 times what is considered safe. And the level of ciprofloxacin there was eight times what is deemed safe.
High antibiotic levels also showed up in several African rivers. These included ones in Accra, the capital of Ghana; near Kenya’s capital city of Nairobi; and near Lagos, Nigeria’s biggest city. High levels also showed up in Lahore, the second-most populated city in Pakistan, and in a river near the Israeli city Nablus.
The highest level of antibiotics in Europe turned up in an urban tributary of the Danube as this river travels through Austria. The most polluted U.S. river was in North Liberty, Iowa, near many livestock farms.
The researchers did some detective work to figure out how the drugs were getting into these water. Google Street View showed some tainted waters were near plants that make medicines. Perhaps they released drug-making wastes into local waters, the researchers say. Photos from several very polluted sites in Africa and Asia, Boxall notes, also showed trash heaped along riverbanks and sewage-carrying trucks.
How deep a river is, how fast it flows and whether a sampling site was downstream of a city or hospital can also affect levels of any drugs found, Boxall says.
He, Wilkinson and their colleagues plan to test how levels of the drugs measured at some sites might affect algae and other organisms. They hope such findings can help officials across the globe take needed action to cut drug pollution.
Antibiotic pollution can fuel drug resistance in microbes. A global survey of rivers finds unsafe levels of antibiotics in 16 percent of sites.
In a massive survey of rivers across 72 countries, researchers found antibiotics at 66 percent of 711 sites sampled. Many of the most drug-polluted waterways were in Asia and Africa, where there hadn’t been much data until now.
Environmental pollution from antibiotics is one driver of microbial drug resistance, which threatens public health. People should be as concerned about resistance evolving abroad as they are about resistance brewing in their own backyards, says William Gaze, a microbial ecologist at the University of Exeter Medical School in England who was not involved with the research. Even if wealthy countries curb antibiotic pollution, drug-resistant microbes can hitch a ride across the globe with traveling people, migrating birds or traded food and livestock, he says. “It’s a global problem, and we need global solutions.”
About a third of the sites surveyed over the last year contained no detectable levels of antibiotics. But 66 percent, or 470 of the sites, tested positive for at least one of 14 types of antibiotics. And almost 16 percent, or 111 sites, contained concentrations considered unsafe, based on safety levels estimated by AMR Industry Alliance, a global biotech and pharmaceutical coalition. The alliance set its safety thresholds based on levels that wouldn’t kill algae in the environment or promote resistance by killing susceptible bacteria.
“I don’t think I was expecting the degree of concentrations that we saw. That was quite eye-opening,” says environmental chemist Alistair Boxall of the University of York in England, who conducted the survey with University of York colleague John Wilkinson. The two presented their results on May 27 and May 28 in Helsinki at a meeting of the Society of Environmental Toxicology and Chemistry.
The scale of the study is unprecedented, Boxall says. Previously, most surveys had focused on North America, Europe and China. So Boxall and Wilkinson sent water collection kits to colleagues all over the world and then tested samples from a total of 165 rivers for 61 drugs, including the 14 antibiotics.
Samples continue to roll in and the researchers plan to release more data in the future. “Ultimately, it would be nice if we could get samples from every country of the world,” Boxall says.
Many sites deemed to have unsafe antibiotic levels were contaminated with more than one of these drugs. The most commonly found antibiotic was trimethoprim, used to treat urinary tract infections, which showed up at 43 percent of the sampled sites. Other commonly occurring antibiotics were sulfamethoxazole, ciprofloxacin and metronidazole. Some of the antibiotics the researchers looked for — including oxytetracycline, amoxicillin and cloxacillin — were not detected at any site.
Samples from Bangladesh’s Kirtankhola River, near the south-central city of Barisal, contained the highest antibiotic concentrations of any surveyed site. The level of metronidazole approached 40,000 nanograms per liter, or about 300 times the safe level. The commonly prescribed drug ciprofloxacin exceeded safe levels by a factor of eight.
High antibiotic concentrations were also found in river samples near the cities of Accra, Ghana; Nairobi, Kenya; Lahore, Pakistan; Lagos, Nigeria; and Nablus, Israel. The most contaminated sites in Europe were in an urban tributary of the Danube in Austria. And the most polluted U.S. river was found in North Liberty, Iowa, near many animal farms.
To figure out how antibiotics were getting into waterways, the researchers did some sleuthing. Google Street View showed that some contaminated sites are near pharmaceutical plants, which could be releasing discharge into the waterways, the researchers say. Photos from several highly polluted sites in Africa and Asia also showed trash heaped along riverbanks as well as sewage-carrying trucks nearby, Boxall says.
River features such as the water’s depth, how fast it flows and whether a sampling site is located downriver from a city or hospital would also have an impact on drug concentrations, Boxall says.
Boxall, Wilkinson and colleagues plan to test how antibiotics at the levels measured might affect algae and other organisms in the environment. The researchers hope their work leads policy makers worldwide to take action toward curbing antibiotic pollution.
Testing shows blue mackerel caught near salmon pens with antibiotic residues of 960µg/kg, making fish ‘not fit for human consumption’
Tasmania’s largest salmon company, Tassal, has revealed wild fish at one of its salmon farms contained antibiotic residues at almost five times the allowed level.
In another case, there were low-level antibiotic traces in wild fish caught more than seven kilometres from another Tassal salmon farm.
Two monitoring reports published by the Environment Protection Authority (EPA) in January show Tassal used 368.5 kilograms of a controversial antibiotic to control disease outbreaks at the two salmon farms last year. There was no public notification when the antibiotics were used or when the monitoring reports were released.
Sheenagh Neill, a spokesperson for Marine Protection Tasmania, said she was concerned about the continuing secrecy surrounding antibiotics use in public waterways. “The community is still not being informed promptly despite the 2022 Legislative Council inquiry into the fish farming industry recommending the ‘timely’ release of information on the use of antibiotics,” she said.
Tassal used 32.5kg of oxytetracycline (OTC) in late February 2023 and early March 2023 at its Butlers lease near Bruny Island national park. The antibiotic was used to treat an outbreak of tenacibaculosis, a disease that can damage the skin, mouth and gills and kill affected fish.
The company used 336kg of the same antibiotic to treat salmon at its Okehampton lease near Triabunna in May 2023. The EPA reported that it followed Tassal detecting a Tasmanian Rickettsia-like organism, a bacterial infection that can result in significant production loss and cause the death of some affected fish.
The World Health Organization classed OTC as “highly important” for human health, and warned its overuse in the food industry could lead to the development of antibiotic-resistant “superbugs”. It described this as “one of the biggest threats to global health”, and has recommended the vaccination of farmed animals as a strategy to reduce the overuse of antibiotics.
