Medicinal drugs have polluted Scotland’s waterways in breach of safety levels more than 2,300 times over seven years, according to data released by the Scottish Government’s environment watchdog.
Ponds, streams, rivers and firths across the country have been contaminated with 26 drugs, including ibuprofen, oestrogen, antibiotics, painkillers, anti-depressants, anaesthetics and caffeine. In the worst cases, recorded concentrations were hundreds or thousands of times higher than those deemed safe.
According to the Scottish Environment Protection Agency (Sepa), drug pollution can damage and kill wildlife by interfering with growth, behaviour and reproduction. It can also endanger human health by helping viruses, bacteria, fungi and parasites to develop resistance to drugs.
Experts and environmentalists have warned of the “potentially serious” impacts of the pollution. Action is “urgently needed” to cut the contamination and reduce the risks, they said.
The drugs find their way into sewers from people going to the toilet after taking them, or flushing them away unused. Sewage treatment “has not been designed to remove such pollutants,” Sepa said — so they end up being discharged into waterways.
Drug pollution of water is a global problem, with a study in June 2022 reporting contamination “of concern” in 104 countries. It recommended immediate action to “bring concentrations down to an acceptable level”.
Bacteria and other bugs developing a resistance to drugs and rendering them ineffective has also been reported as a “significant threat to humanity”. A study published in The Lancet in January 2022 concluded that it was a leading case of death worldwide, killing about 3,500 people every day.
Drug pollution in breach of safety levels
Comprehensive data on the presence of pharmaceuticals in water in Scotland has been compiled and published for the first time by Sepa, with the help of NHS Highland, Scottish Water and the University of the Highlands and Islands. Samples were taken from around 30 sewage plants and other sites between 2013 and 2019.
The samples show concentrations of individual drugs in surface waters at specific locations, often downstream from sewage treatment plants. The database also highlights exceedances of the “predicted no-effect concentration” (PNEC) of each drug — the level above which they could cause harm.
An analysis of the data by The Ferret has revealed that concentrations of the widely-used anti-inflammatory painkiller, ibuprofen, exceeded the PNEC 768 times between 2013 and 2019. Oestrogen, used for contraception and hormone therapy, breached the PNEC 612 times.
Other drugs that frequently exceeded the PNEC were antibiotics such as erythromycin and clarithromycin, the anti-epilepsy drug, carbamazepine, and anti-depressants. In 18 samples the anaesthetic, lidocaine, was above the PNEC, and in five samples, the painkiller paracetamol.
Many of the breaches were found near sewage works in Lothian, Lanarkshire, Tayside and Glasgow. Breaches were also detected in the River Almond in Lothian, the Clyde in Glasgow and the Don in Grampian, as well as in the Firth of Forth, Cromarty Firth and the Firth of Tay.
The recorded concentrations of drugs in some samples were many times higher than the PNEC. Recorded levels of caffeine, used as a stimulant in some medicines, were more than 50,000 times the PNEC in the River Almond and near sewage works at Harthill in Lanarkshire and Seafield in Lothian during 2015.
Levels of carbamazepine were more than 1,000 times the PNEC in water sampled downstream of the Archiestown sewage plant in Grampian in 2018. Concentrations of ibuprofen were 660 times higher than the PNEC downstream of the Largoward sewage plant in Fife in 2017.
Action on drug pollution ‘urgently needed’
Publication of the data was welcomed by Fidra, an environmental charity based in North Berwick that specialises in water pollution. But it expressed disappointment that it failed to include information on many other toxic pollutants already reported in England and Wales.
“The high levels found indicate that action is urgently needed to decrease their input to the environment and increase remediation, for example improving removal through waste water treatment works, “ said Fidra’s senior project manager, Dr Clare Cavers.
“Alarmingly chemicals from treatment works are entering waterways in addition to chemicals from other sources such as agricultural and landfill run off. Sewage sludge that has been removed during water treatment is often applied to farmland, where it can then be washed into water bodies and therefore add to the chemical load.”
According to Cavers, understanding of how the pollution harms wildlife and human health is “very poor”. Research so far has suggested that the impacts could be “significant”, particularly when substances break down and interact.
“A strong precautionary and preventative approach is needed, with policies and infrastructure to decrease inputs while also increasing monitoring and research to understand the impacts better,” she told The Ferret.
Professor Andrew Watterson, an environmental expert from the University of Stirling, described the impacts of drug pollution as “potentially serious”. Antibiotics at very low levels could harm wildlife, and other pollutants had been linked to cancer, heart disease and other problems, he said.
“Reducing domestic medicines disposal into water supplies is important. Also, reducing antibiotic use in both health and agricultural settings needs to be stepped up.”
The Scottish Greens argued that sewage treatment should be reviewed. “This database reveals the astonishing levels of pharmaceuticals in our water which, given the significant impact this can have on wildlife and the environment, is a major cause of concern,” said the Green MSP, Gillian Mackay.
Professor Stuart Gibb, director of the Environmental Research Institute at the University of the Highlands and Islands, described the pollution as a “globally recognised” problem. “We have been monitoring pharmaceuticals in natural and waste waters in Scotland for many years now, and have demonstrated their undesirable presence in some rural, as well as urban, water environments,” he said.
‘Return unused drugs to pharmacies’
Sepa stressed that the pollution had to be tackled by collaboration and innovation. “It is not an issue that will be solved by one organisation alone or by focussing on only one part of the problem,” said the agency’s head of environmental quality, Martin Marsden.
“This is the first time that environmental data from Sepa, Scottish Water and various academic studies have been brought together in one place in a way that can be interrogated, alongside information from the NHS. This tool will be crucial to improving our understanding of the challenge and helping us design and deliver interventions to address it.”
Sepa accepted that the data showed “some relatively high concentrations”. But it cautioned that single samples couldn’t always be compared directly to PNECs as they were often set as averages over longer periods.
The public could help cut the pollution by returning old or unused drugs back to pharmacies, Sepa pointed out. It promised to keep working to “identify and prioritise the medicines that are presenting the greatest risks to our water environments”.
NHS Highland highlighted the many benefits of medicines. “Some also cause harm to the environment, but it is unrealistic to simply call for medicines not to be used in an attempt to cut pollution,” said a spokesperson.
“A key part of reducing pollution will be educating people about possible environmental impacts and encouraging them to return unwanted or out-of-date medicines to pharmacies for correct disposal rather than flushing them down the toilet or putting them into domestic waste bins.”
The spokesperson added: “Awareness campaigns can also help to reduce the expectation of the need for antibiotics for coughs and colds, thereby reducing their overall prescribing. We will be working to also help educate prescribers and give them information on environmental impact to help them make sustainable prescribing choices.”
Scottish Water emphasised its commitment to working to protect and enhance Scotland’s water environment. “This tool will help in developing the most sustainable methods to address the emerging issue of pharmaceuticals in waste water,” said the government company’s chief scientist, Elise Cartmell.
Cover image thanks to iStock/resavac.