Rivers around the world are contaminated with dangerous levels of antibiotics, according to a major new study.
Concentrations of antibiotics in some waterways exceed safe levels by 300 times, a global team of scientists led by the University of York found.
The Thames was contaminated with five antibiotics, including levels of ciprofloxacin – used to treat skin and urinary tract infections – that were three times what is considered safe.
Researchers looked at 14 commonly used antibiotics in rivers flowing through 72 countries and found antibiotics were in two-thirds of samples.
Scientists fear antibiotics in rivers cause bacteria to develop resistance meaning they can no longer be used in medicines for humans. The UN estimates that the rise in antibiotic resistance could kill 10 million people by 2050.
“A lot of the resistance genes we see in human pathogens originated from environmental bacteria,” Professor William Gaze, a microbial ecologist at the University of Exeter who was not involved in the study, told The Guardian.
Drugs get into rivers via human and animal waste, as well as leaks from wastewater treatment and drug manufacturing sources.
In one site in Bangladesh, levels of metronidazole – which is used to treat mouth and skin infections – were 300 times greater than what is considered safe. The most common antibiotic was a urinary tract infection antibiotic called trimethoprim, which was present in 307 of 711 sites tested.
Scientists flew out 92 testing kits to partners across the world who took samples from local rivers. Researchers found Bangladesh, Kenya, Ghana, Pakistan and Nigeria were home to the most contaminated rivers. The team said that the safe limits were most frequently exceeded in Asia and Africa.
However, sites in Europe, North America and South America also had high levels of contamination showing that antibiotic contamination was a “global problem”.
Professor Alistair Boxall, from the York Environmental Sustainability Institute, said: “The results are quite eye opening and worrying, demonstrating the widespread contamination of river systems around the world with antibiotic compounds.
“Many scientists and policy makers now recognise the role of the natural environment in the antimicrobial resistance problem. Our data show that antibiotic contamination of rivers could be an important contributor.
“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.”
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Rachid and Khaled, buffalo breeders in south Iraq look out over the dried out marshes (Photo: Bel Trew)
Bel Trew
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Beached boats lie on parched land which was once inhabited by buffalo breedes in Iraq’s famed marshlands (Photo: Bel Trew)
Bel Trew
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Smoke billows from an oil refinery in the background of a dried out marsh (Photo: Bel Trew)
Bel Trew
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Water Buffalo sit in shallow water in Chibayish marsh in Iraq (Photo: Bel Trew)
Bel Trew
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An Iraqi buffalo breeder says that the waters used to stretch to the horizon but have disappeared in a severe drought (Photo: Bel Trew)
Bel Trew
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Families of buffalo breeders fear they will have to move to the cities to find work as the waters have dried up (Photo: Bel Trew)
Bel Trew
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A buffalo breeder points out where the original waterline was when the marshes were not dried out (Photo: Bel Trew)
Bel Trew
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This reed hut used to be surrounded by rich marshes which have now dried out in Iraq’s water crisis (Photo: Bel Trew)
Bel Trew
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Famers south of Baghdad point to an emptying salty water pond which once irrigated their crops (Photo: Bel Trew)
Bel Trew
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A young boy plays in an empty irrigation canal south of Baghdad, once known as a greenbelt (Photo: Bel Trew)
Bel Trew
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Young children play in putrid water in an empty irrigation canal in an area south of Baghdad (Photo: Bel Trew)
Bel Trew
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Children from a farming community play by dried up river beds and canals south of Baghdad (Photo: Bel Trew)
Bel Trew
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The Euphrates near Iraq’s famed marshes is drying up and at its deepest is just half a metre (Photo: Bel Trew)
Bel Trew
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Young women make traditional tapestries in the Marshlands of Iraq (Photo: Bel Trew)
Bel Trew
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Mahdi Sadah, 30 a father of twelve, who also been displaced said he has lost 6 of his 15 buffalo due to the salty water in the marshes (Photo: Bel Trew)
Bel Trew
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Mahdi Sadah, 30 a father of twelve, with some of his children outside their traditional reed hut in the marshlands of Iraq (Photo: Bel Trew)
Bel Trew
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Water buffalo are dying in their droves in the marshlands of Iraq due to high salinity of the receding waters (Photo: Bel Trew)
Bel Trew
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A traditional reed hut which houses a family of eight in the marshlands in Iraq (Photo: Bel Trew)
Bel Trew
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A young girl suffers from malnutrition as her family struggle to make money for food in the marshlands of Iraq (Photo: Bel Trew)
Bel Trew
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Inside the rudimentary reed huts where the Marsh Arabs live in south Iraq (Photo: Bel Trew)
Bel Trew
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A young girl and her baby sister take cover from searing summer temperatures of Iraq (Photo: Bel Trew)
Bel Trew
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Emaciated water buffalo cool of in the shrinking water of the marshes in Iraq (Photo: Bel Trew)
Bel Trew
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Rachid Jassim, a Marsh Arab, explains how he has lost $1000s of dollars being displaced due to the water crisis in Iraq (Photo: Bel Trew)
Bel Trew
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Rachid and Khaled, buffalo breeders in south Iraq look out over the dried out marshes (Photo: Bel Trew)
Bel Trew
2/23
Beached boats lie on parched land which was once inhabited by buffalo breedes in Iraq’s famed marshlands (Photo: Bel Trew)
Bel Trew
3/23
Smoke billows from an oil refinery in the background of a dried out marsh (Photo: Bel Trew)
Bel Trew
4/23
Water Buffalo sit in shallow water in Chibayish marsh in Iraq (Photo: Bel Trew)
Bel Trew
5/23
An Iraqi buffalo breeder says that the waters used to stretch to the horizon but have disappeared in a severe drought (Photo: Bel Trew)
Bel Trew
6/23
Families of buffalo breeders fear they will have to move to the cities to find work as the waters have dried up (Photo: Bel Trew)
Bel Trew
7/23
A buffalo breeder points out where the original waterline was when the marshes were not dried out (Photo: Bel Trew)
Bel Trew
8/23
This reed hut used to be surrounded by rich marshes which have now dried out in Iraq’s water crisis (Photo: Bel Trew)
Bel Trew
9/23
Famers south of Baghdad point to an emptying salty water pond which once irrigated their crops (Photo: Bel Trew)
Bel Trew
10/23
A young boy plays in an empty irrigation canal south of Baghdad, once known as a greenbelt (Photo: Bel Trew)
Bel Trew
11/23
Young children play in putrid water in an empty irrigation canal in an area south of Baghdad (Photo: Bel Trew)
Bel Trew
12/23
Children from a farming community play by dried up river beds and canals south of Baghdad (Photo: Bel Trew)
Bel Trew
13/23
The Euphrates near Iraq’s famed marshes is drying up and at its deepest is just half a metre (Photo: Bel Trew)
Bel Trew
14/23
Young women make traditional tapestries in the Marshlands of Iraq (Photo: Bel Trew)
Bel Trew
15/23
Mahdi Sadah, 30 a father of twelve, who also been displaced said he has lost 6 of his 15 buffalo due to the salty water in the marshes (Photo: Bel Trew)
Bel Trew
16/23
Mahdi Sadah, 30 a father of twelve, with some of his children outside their traditional reed hut in the marshlands of Iraq (Photo: Bel Trew)
Bel Trew
17/23
Water buffalo are dying in their droves in the marshlands of Iraq due to high salinity of the receding waters (Photo: Bel Trew)
Bel Trew
18/23
A traditional reed hut which houses a family of eight in the marshlands in Iraq (Photo: Bel Trew)
Bel Trew
19/23
A young girl suffers from malnutrition as her family struggle to make money for food in the marshlands of Iraq (Photo: Bel Trew)
Bel Trew
20/23
Inside the rudimentary reed huts where the Marsh Arabs live in south Iraq (Photo: Bel Trew)
Bel Trew
21/23
A young girl and her baby sister take cover from searing summer temperatures of Iraq (Photo: Bel Trew)
Bel Trew
22/23
Emaciated water buffalo cool of in the shrinking water of the marshes in Iraq (Photo: Bel Trew)
Bel Trew
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Rachid Jassim, a Marsh Arab, explains how he has lost $1000s of dollars being displaced due to the water crisis in Iraq (Photo: Bel Trew)
Bel Trew
Dr John Wilkinson, from the University of Exeter, said: “Until now, the majority of environmental monitoring work for antibiotics has been done in Europe, North America and China. Often on only a handful of antibiotics. We know very little about the scale of problem globally.
“Our study helps fill this key knowledge gap with data being generated for countries that had never been monitored before.”
The findings will be unveiled at the annual meeting of the Society of Environmental Toxicology and Chemistry in Helsinki on 27 and 28 May.