Pharmaceutical pollution of rivers around the world is a 'global threat to the environment and human health', according to the most comprehensive study to date..

Pharmaceuticals and other bioactive compounds used by humans are known to harm wildlife, and antibiotics in the environment increase the risk of drug resistance, one of the biggest threats to humanity..

Scientists measured the concentration of 61 active pharmaceutical ingredients (APIs) at more than 1,000 sites along 258 rivers in 104 countries, covering all continents. Only two places remained uncontaminated - Iceland and a village in Venezuela where the indigenous population does not use modern medicines..

The most commonly detected APIs were the difficult-to-break down antiepileptic drug carbamazepine, the diabetes drug metformin, and caffeine.. All three have been found in at least half of the studied sites.. Antibiotics were found in dangerous amounts at one in five sites, while many sites had at least one API at a level of accumulation that is considered harmful to wildlife and causes detrimental effects, in particular the feminization of fish.

APIs enter rivers after consumption by humans and livestock and are released into the sewer system or directly into the environment, although some may be released by pharmaceutical factories.

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Hotspots with very high API levels include Lahore in Pakistan, La Paz in Bolivia and Addis Ababa in Ethiopia. Madrid in Spain was in the top 10 places with high cumulative concentration, while Glasgow, UK and Dallas, USA were in the top 20..

“WHO, UN and other organizations say that antimicrobial resistance is the biggest threat to humanity, this will be the next pandemic. In 19% of all the sites we examined, antibiotic concentrations exceeded expected levels of stimulating bacteria to develop resistance,” said John Wilkinson, a scientist at the University of York in the UK and lead the study..

A study published in January found that 5 million people died in 2019 from antibiotic-resistant bacterial infections.. Regions that have suffered the most from resistance to such drugs have the worst rates of drug contamination. This raises speculation about a relationship between river pollution and increased resistance to infections.. In a region in Bangladesh, levels of the antibiotic metronidazole were 300 times the safe limit, likely due to leaks from pharmaceutical manufacturing.

Drug pollution has already been proven to harm wildlife, from antidepressants that blunt starlings' hunger to birth control drugs that reduce fish populations..

“If I were a fish living in one of these rivers, I would be very worried right now. However, the level of pollution of water bodies is not enough to harm people swimming in them, ”said Wilkinson..

The study, published in the journal Proceedings of the National Academy of Sciences, is the largest to date and reflects the impact of 470 million people on river pollution.. Scientists have concluded that pharmaceutical pollution is a global threat to the environment and human health.

Previously, almost all measurements were made in Western Europe and North America, but a recent study has shown that pharmaceutical contamination is often much higher elsewhere.. The work included an analysis of 36 countries where the number of APIs was measured for the first time, in particular, these are the states of Africa and South America..

The antidepressants citalopram and venlafaxine, the antihistamines cetirizine and fexofenadine, the antibiotic trimethoprim, and the anesthetic lidocaine were found among the drugs found on every continent except Antarctica.. The Kai Tak River in Hong Kong had 34 different APIs found at a single site, the highest number recorded.

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There are now more than 2,500 pharmaceuticals used in the world, but modern technologies allow us to analyze only 50-100 from a single sample, so scientists have focused on the most commonly used.

The highest drug concentrations were found in low- and middle-income countries, including India and Nigeria. Researchers believe that this may be due to the fact that people in such states have enough income to buy pharmaceuticals, but live in places where there is no high-quality sewerage system that would remove the remains of hazardous substances..

The study did not include measuring the amount of illegal drugs such as cocaine and MDMA found in rivers at levels harmful to wildlife, although upcoming sample analysis may do so..

Scientists hope the study will help focus on pharmaceutical cleanup efforts and regions most at risk.

“We know that connecting to quality sewerage and wastewater treatment is the key to minimizing, if not eliminating, pharmaceutical concentrations.. However, it is very expensive as there is a lot of infrastructure involved,” says John Wilkinson..

More careful use of drugs is another way to reduce pollution, said the scientist, particularly antibiotics, which are available cheaply without prescriptions in many countries and are widely used unnecessarily, for example, to treat the common cold..

“Pharmaceuticals are almost ubiquitous in the world’s rivers. The study shows that a fairly large range of drugs exceed " Bacteria do not respect national borders, so if a new resistant bacterium appears on one side of our planet, it will soon become a danger to everyone,” said Joakim Larsson, professor at the University of Gothenburg, Sweden, who was not involved in the study..

Researchers aim to increase number of countries covered as COVID-19 pandemic put their study on hold. The scientists are also expanding the list of drugs they are studying and hope to begin assessing seasonal changes in river pollution levels..

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Scientists from the University of Insubria say that Antarctica's only flowering plants, Antarctic meadow grass and Quito colobanthus, are rapidly expanding their range in response to anthropogenic climate change..

Observations that were carried out on Signy Island showed that since the 1960s, these plants began to occur much more often and colonized new territories, reports N + 1.