Superbugs: How drugs that cure you end up in rivers, soils

At 25, Vanessa Carter was in a devastating car crash in Johannesburg. It broke every bone on the right side of her face, and set her on a years-long journey through multiple reconstructive surgeries.  

Six years on, Carter received a prosthetic implant to reconstruct her cheekbone. Perhaps the worst of her ordeal was over. But one day, she noticed some pus seeping from her face. It was an infection. And for nearly a year, it wouldn’t go away.  

“I was taking antibiotics, I was seeing my doctors, but nobody could give me answers,” she told DW. “And all this time this bacterial infection was basically eating away at the tissue on my face.”

The culprit, it turns out, was MRSA — methicillin resistant Staphylococcus aureus — one of a growing number of superbugs against which antibiotics have stopped working.

A looming global crisis with 10 million deaths per year 

Antimicrobial resistance — when bacteria, viruses, fungi and parasites evolve to defeat the drugs designed to kill them — has been identified as a major global health challenge by the UN. 

By 2050, drug-resistant superbugs could claim 10 million lives annually. If left unchecked drug-resistant infections could cost $412 billion (€352 billion) annually by 2050and cut $3.4 trillion dollars from GDP per year over the next decade.

One reason behind their spread is the mis- or overuse of antibiotics in healthcare. Another is antibiotic pollution in the environment. 

“Perhaps you irrigate a crop with water that contains these bacteria. And then we consume the crop or perhaps we drink some water that contains these genes,” said Alistair Boxall, an environmental science professor at the UK’s University of York. “That resistance will be getting back into our bodies.”

Drugs have been found all over the world

Pharmaceuticals have been detected in rivers and soils all over the world. A recent study Boxall was involved in, tested river water at more than 1,000 sites in 104 countries.

“We searched for 61 different pharmaceuticals and apart from a very small number of sites, we found pharmaceuticals everywhere,” Boxall said.  

The only sites free of drug residues were Iceland and a remote village in the Venezuelan rainforest whose Indigenous residents don’t use modern medicines.

Everywhere else, researchers found high levels of the diabetes medication metformin, alongside antibiotics and medicines for depression, epilepsy, pain, and allergies. A quarter of the sites showed pharmaceutical levels considered harmful to wildlife. 

How are drugs ending up in the environment?

When we take medication, our bodies only absorb part of it. The rest is excreted and ends up in sewage systems. Antibiotics are also frequently overprescribed and overused. Humans consume more than 30,000 tons of the medicine a year. Around a third of that lands in rivers.

Many wastewater treatment plants aren’t designed to fully remove these substances, so traces pass through into rivers, lakes, and soils.

Globally, just over half of all wastewater is treated before release.

In many lower-income countries, treatment systems are limited or absent entirely. Meaning contamination is often much worse in parts of sub-Saharan Africa, in South Asia and Latin America.

Pharmaceutical manufacturing plants are another source of pollution, as is agriculture. Large amounts of drugs are given to farm animals. Some estimates suggested that at least double the amount given to humans goes to treat livestock. And when their manure is spread as fertilizer, nearby waterways can become contaminated. 

The effects on wildlife can be severe. 

Research from North America shows that synthetic hormones in the contraceptive pill found caused the “feminization” of male fish in one water, leading to reproductive failure and population collapse. Another UK study found the antidepressant Prozac caused starlings to lose their appetite and libido.

What are solutions to counter antimicrobial resistance?

Upgrading wastewater treatment is a key part of the solution.

In many Western countries, this would require an extra level of treatment — and using chemicals or activated carbon filters, for example, to capture those pharmaceutical compounds. 

But advanced treatment uses a lot of energy, potentially adding to greenhouse gas emissions. It could also create other toxic compounds in the process.

And “it does cost a lot of money,” Boxall added.

Still, the European Union is pushing ahead. Under its Urban Wastewater Treatment Directive, member states will be required to upgrade treatment plants in the coming years, with 80% of the cost to be covered by the pharmaceutical and cosmetics industry — a provision that has met with fierce resistance from the pharmaceutical lobby.

The EU has also introduced rules reducing pharmaceuticals in surface and groundwater and will require member states to track  antimicrobial resistance in wastewater.

In the US, the Environmental Protection Agency has moved to include pharmaceuticalson a list of drinking water contaminants for the first time.

But Boxall says change is not happening fast enough and that advanced filtering is not realistic for poorer countries often facing the worst pharmaceutical contamination.

Does biodegradable medication exist?

Klaus Kümmerer, a professor of sustainable chemistry at Leuphana University of Lüneburg in northern Germany, thinks the answer lies in designing drugs that would fully degrade once they have served their function in the human body.

“That would be the gold standard: mineralizing to carbon dioxide and water,” he said.

His team has developed anti-cancer drugs that biodegrade completely in wastewater treatment plants. They’ve also patented two biodegradable alternativesto the antibiotic Ciprofloxacin, which is considered particularly difficult to break down.

Once their antibiotic has done its job, and reaches the bladder, the change in pH or acidity triggers the degradation process.

But the antibiotic never reached the market.

“We as a small university working group, we cannot develop a compound and bring it on the market. Now industry has to step in,” said Kümmerer. 

Designing cleaner drugs and not relying on costly wastewater treatment upgrades is the real long-term solution to pharmaceutical pollution, he believes. But using fewer pharmaceuticals in the first place, meaning using medicines more carefully, and doctors prescribing only what is strictly necessary, is also important

“Antibiotics do not kill viruses and viruses are responsible for a cold,” said Kümmerer.

“My grandma used to say: If you are sick with a cold or something like this, it takes about a week if you take pharmaceuticals and it takes about seven days if you don’t.”

This article was based on an episode of Living Planet produced by Natalie Muller. Listen to the full episode here.

Edited by: Jennifer Collins