Nearly half of the world’s rivers are poisoned by over-the-counter and prescription drugs, according to new research.
They range from antibiotics, antidepressants and painkillers to oral contraceptives, hay fever pills and tranquilizers.
The River Clyde in Scotland is the most polluted in the UK from a pharmaceutical point of view, with carbamazepine, an epilepsy drug, being the most common in almost 70% of UK rivers.
Of 54 sampling sites in the UK, drugs were detected in 50, with only four in the remote Snowdonia region of Wales being clean.
These levels are potentially toxic to humans. Fish and other wildlife are also under threat, endangering ecosystems. Drugs that target hormones, for example, have induced sexual changes in marine animals.
The study found that more than 43% of sites had “concerning” amounts of active pharmaceutical ingredients (APIs), including 23 that exceeded those considered “safe”.
It was based on 1,052 locations in 104 countries around the world, the largest analysis of its kind.
Corresponding author Alejandra Bouzas-Monroy, Ph.D. student at the University of York, said, “This is the first truly global assessment of the impacts of single pharmaceuticals and pharmaceutical mixtures in river systems.
“Our results show that a very high proportion of rivers worldwide are threatened by pharmaceutical pollution.
“We should therefore do much more to reduce the emissions of these substances into the environment.”
They are released into the environment during production, use and disposal. They are more likely to be found in surface waters such as streams, rivers, lakes, reservoirs and wetlands.
The findings indicate that contamination is a global problem damaging rivers from the Thames to the Amazon.
Bouzas-Monroy said: “More than 1,900 APIs are used to treat and prevent disease in humans. It is inevitable that these substances will be emitted into the natural environment.
“There is growing concern that exposure to these APIs may negatively affect ecosystem health because they are designed to interact with receptors and biochemical pathways in humans.
“Many are retained in non-target organisms and have the potential to cause toxicological side effects.”
Studies on the lake have shown that “the pill” and other synthetic estrogens cause hormonal disruption.
Diclofenac, a popular painkiller, has caused a noticeable decline in vulture populations on the Indian subcontinent, leading to potential impacts on human health.
Antidepressants have been shown to affect the behavior of fish, which could disrupt the food chain making them more vulnerable to predators.
It is feared that the presence of antimicrobial compounds in the environment could contribute to the selection of drug-resistant bacteria, fueling the emergence of deadly superbugs.
Bouzas-Monroy said: “The lack of global API monitoring data means that for many parts of the world we have no idea of the level of potential impacts.
“Therefore, we used a unique dataset of concentrations of 61 high-use APIs in rivers from 104 countries to perform the first truly global holistic assessment of their potential ecotoxicological effects.”
The British team discovered that pharmaceutical pollution contaminates water on all continents. In North America, sulfamethoxazole and caffeine had the highest concentrations.
A total of 54 sampling sites were selected in the UK. Drugs were detected in all – except four in the remote Snowdonia region of Wales. The most contaminated was the River Clyde in Glasgow.
The most frequently detected drug in UK waterways was carbamazepine prescribed for epilepsy, found at 69% of sites.
Co-author John Wilkinson, also from the University of York, said: “There are 19.5 million people living in the cities where we have done monitoring work in the UK – London, Leeds, York, Glasgow, North Wales and Belfast. That’s almost a third of the population.”
The availability of API ecotoxicity data has increased significantly in recent years as the pharmaceutical industry becomes more transparent.
Bouzas-Monroy said: “Twenty-three APIs had concentrations for at least one sampling location above concentrations where an effect on organisms might be expected.
“Ten of those identified, including molecules used to treat depression, bacterial infections, epilepsy and anxiety, as well as hormone treatments and stimulants, were found to be at levels of ecotoxicological concern.”
Characterizing the 61 APIs may just be “the tip of the iceberg” as there are almost 2,000 in circulation, according to the study. Actual impacts on aquatic systems are expected to be higher.
Bouzas-Monroy said: “The rivers that have been monitored will not only contain APIs but also other pollutants such as industrial chemicals, pesticides and metals.”
She added: “We present for the first time a comprehensive assessment of the potential ecotoxicological impacts of APIs on aquatic ecosystems.
“We demonstrate that approximately 43.5% of river locations globally have concentrations where ecotoxicological effects might be expected, with some locations expected to experience effects across multiple trophic levels and endpoints.
“If we are to achieve the 17 UN Sustainable Development Goals, especially Goal 6, ‘Clean Water and Sanitation’, we must urgently address the global problem of pharmaceutical pollution.”
The regions of the world most affected are those that have been the least analysed: sub-Saharan Africa, South America and parts of South Asia.
Less than a quarter of wastewater is treated – and the technology is unable to filter most pharmaceuticals.
It is hoped that increased monitoring will lead to strategies that limit the effects.
A cutting-edge scan in York identified propranolol, a beta-blocker for heart disease, and loratadine which is taken for allergies. Others included the common antibiotics sulfamethoxazole and ciprofloxacin for bacterial infections.
They can disrupt the reproductive abilities of organisms, alter behavior or physiology – and even alter heart rhythm.
The amount of drugs seeping into waterways will increase by two-thirds before 2050, endangering freshwater ecosystems.
The study was published Wednesday in Environmental toxicology and chemistry.
This story was provided to Newsweek by Zenger News.