Researchers have found a ‘staggering’ amount of prescription drugs in sea water off the UK’s South Coast, alongside pesticides and illegal drugs such as cocaine.

The findings, released on Friday as part of an ongoing study, highlighted the issue of chemical pollution from wastewater, which researchers said poses a threat to aquatic ecosystems and marine life.

‘The release of human pharmaceuticals into aquatic ecosystems is an environmental problem we should consider seriously,’ said Professor Alex Ford, from the University of Portsmouth’s School of Biological Sciences, which partnered with Brunel University and local interest groups to conduct the study.

Through analysing 288 samples of water collected by the Clean Harbours Partnership campaign group last year off the coasts of Hampshire and West Sussex, the researchers have so far detected more than 50 compounds across 22 sites. This included pharmaceuticals such as antidepressants, drugs for type 2 diabetes and bladder infections, as well as  recreational drugs and pesticides.

They have also found traces of these chemicals within marine organisms, such as crabs and oysters.

‘This is important, because we know that aquatic ecosystems are under threat from pharmaceuticals and farming practices such as biocides and fertilisers,’ said Professor Ford.

His previous research found that tiny quantities of antidepressants in water can affect wildlife, while drugs can even affect the behaviour and biological make-up of creatures like crustaceans and molluscs, including causing them to change colour and affect their growth or reproductive frequency.

He said: ‘There is a staggering list of prescription drugs passed from humans to wastewater treatment plants and into receiving streams, estuaries, or oceans by direct consumption, metabolism, and excretion or by toilet flushing of old prescriptions.’

In particular, the group highlighted the release of human pharmaceuticals into aquatic ecosystems when wastewater was discharged from combined sewer overflows (CSOs) after heavy rain.

‘Chemical pollution from CSOs is becoming a real cause for concern due to the number of chemicals that are being found all over the environment and not just in the UK,’ said Dr Tom Miller, a researcher on the project from Brunel University.

Meanwhile, Rob Bailey, co-founder of the Clean Harbours Partnership campaign group, said that the project, which was crowdfunded locally, was beginning to give an insight into ‘the cocktail of chemicals polluting our sea water and their sources’.

‘The presence of partly digested antidepressants, drugs for type 2 diabetes and bladder infections is concerning. So little is known about their impact on marine life,’ he added.

In a blog for the Royal Pharmaceutical Society (RPS), Sharon Pfleger, consultant in pharmaceutical public health at NHS Highland, said that anywhere between 30% and 100% of medicines taken are excreted by the human body and flushed down the toilet, entering the sewage system, while skin creams and lotions can be washed off in the shower or bath.

And since not all medicine traces are removed by wastewater treatment plants, she said that small amounts of these chemicals entering aquatic ecosystems could impact the physiology, behaviour and reproduction of sea life.

And she added that the ‘biggest threat from environmental pollution with medicines’ was the development of antimicrobial resistance (AMR).

A recent report by the World Health Organisation (WHO) found high levels of antimicrobial resistance in bacteria causing life-threatening bloodstream infections, as well as increasing resistance to treatment in several bacteria causing common infections in the community.

A study by NHS Highland’s One Health Breakthrough Partnership found seven commonly used medicines in the hospital’s wastewater, including painkillers, antibiotics, heart medicines and antidepressants.

The group has now developed an information video informing patients about the environmental impact of antibiotic pollution and how to safely dispose of antibiotics.

NHS Highland is also looking into introducing environmental considerations into its medicine’s formulary ‘to give prescribers information to make the best choice for patients, as well as the safest choice for the environment’.

And Ms Pfleger said that the ‘biggest impact’ that clinicians can make ‘is not to prescribe medicines in the first place’, adding that patients should be actively involved in their treatment options, whether that is a procedure, a medicine or a lifestyle change.

John Penicud, director of wastewater operations at Southern Water, which manages wastewater  around the South Coast collection sites, said that tackling chemicals and impurities, especially ‘forever chemicals’ like those found in pesticides, was ‘a global challenge that requires close collaboration of industry, agriculture, and other sectors including water companies and regulators’.

‘Our treatment processes already comply with stringent Environment Agency rules relating to the removal of contaminants, and we’re working with partners to explore how we can go further – through the use of cutting-edge technology and science, and investing in our network to improve treatment,’ he added.

A spokesperson for the Environment Agency (EA) told The Pharmacist that it was ‘holding the water industry to account on a scale never seen before’, as well as funding sewerage and storm overflow improvements.

And they said that the EA had been working with water companies on chemicals investigations including a range of pharmaceuticals discharged from in treated sewage effluent.

The EA also uses targeted screening in water samples to monitor for more than 1,614 chemicals, including a wide variety of pharmaceuticals, it said.

And it has developed a Prioritisation and Early Warning System for ‘chemicals of emerging concern’, to consider the potential risks of these chemicals to surface waters, including coastal waters and rivers, as well as groundwater and soils.

This system allows the EA to prioritise whether a substance – including many pharmaceuticals – may be a possible chemical of concern.

And the EA spokesperson confirmed that over the next few months, a working group will be set up to bring together the pharmaceutical industry, research institutes and government bodies to identify and fill evidence gaps and eventually form evidence-based policy around the environmental impact of pharmaceuticals.