How do we keep medicines out of the environment?

Painkillers, contraceptives, antibiotics, antidepressants – we take quite a lot of them. Once these medicines have been taken, however, the active ingredients or their breakdown products leave our bodies and enter the sewerage system through the toilet. These pharmaceutical residues ultimately reach our rivers and other surface waters, sometimes in concentrations that pose a risk to organisms in the environment. ‘Given that we share waterways in North-Western Europe, such residues from upstream countries eventually end up here’, observes Eelko Hak, professor of pharmaco-epidemiology. ‘We therefore need a collaborative European approach that brings together experts in water technology and pharmacy.'

FSE Science Newsroom | René Fransen

Medicines that end up in surface water can affect aquatic animals and plants. For example, hormones from contraceptives have an effect on the reproduction of fish, and antidepressants can change their behaviour and affect the production of eggs and sperm. Furthermore, pharmaceutical residues must be removed before surface water or groundwater can be used as drinking water, which is a costly process. The Interreg-NWE project PREWAPHARM (Prevention of pollution of Water by Pharmaceuticals) is therefore aimed primarily at reducing the volume of pharmaceutical residues in our sewerage system.

Despite their extensive knowledge of the problem, Hak and his European colleagues have yet to grasp its true magnitude. Hak explains, ‘Official measurements of water quality – for example, by the Waterboards (Waterschappen) and Rijkswaterstaat – record where and when pharmaceutical residues are present. The risks of these residues remain largely unknown, however, due to a lack of environmental thresholds for them.'

Identifying the most common culprits

Hak and his team aim to identify the most commonly used drugs in North-West Europe. Although more than 2,000 different medicines are available at pharmacies, only around 150 have been measured in surface waters. Together with colleagues in the Netherlands (e.g., from the Dutch National Institute for Public Health and the Environment; RIVM), as well as in Germany, Belgium, and Ireland, Hak is compiling a top-25 priority list of frequently prescribed drugs that could affect the aquatic environment. This will make it possible to target water-treatment and prevention efforts at the most common culprits. Once the list has been completed (somewhere this autumn), the next step will be to identify the best ways to mitigate their risks. Collaborating water technologists can use various filtration techniques to examine removal rates.

Prevent, Reduce, Remove

The researchers are considering various risk-mitigation options, tracing the entire chain back from sewerage to the patient, to the pharmacy, to the doctor, and to pharmaceutical companies. Hak explains, ‘One option could be to filter out medicines from the sewerage at places where they are most abundant, like at a hospital or at a nursing home. We would like to learn whether this is cost-effective and actually necessary. Drug removal currently takes place primarily at water treatment plants’. By the time medicines arrive at these plants, however, they are strongly diluted, thus making the removal process more difficult. Moreover, current systems are not always designed to remove micropollutants. The scientists are therefore examining the cost-effectiveness and sustainability of installing a filter under a pharmacy sink or at the end of a sewerage pipe.

A different educational approach to reducing pharmaceutical residues in our water could be to raise awareness amongst patients. ‘Surplus drugs can be handed in at most local pharmacies, but people often throw them in the bin or flush them down the toilet’, notes Hak. A campaign to alert people to the dangers of disposing surplus medication through the toilet would help. ‘This was done years ago, but it requires a sustained effort in close collaboration with the pharmacists.'

Antidepressants with PFAS

Prevention can also begin in the pharmacy or the doctor’s office. Hak observes, ‘In some cases, different medicines are available for a given treatment, with different environmental impacts.’ The RIVM is developing an assessment framework for comparing the sustainability aspects of various pharmaceuticals. Professional organizations like the Royal Dutch Pharmacists Association (KNMP) and the Dutch College of General Practitioners (NHG) are part of a user group for incorporating this assessment system into their guidelines. This process requires education on sustainable drug use for all parties – from students to professionals. Hak and his colleagues will be providing this as well.

One long-term solution could involve designing environmentally friendly drugs. ‘For example, the antidepressant fluoxetine contains a forever-chemical in the PFAS group. This is done to stabilize the drug and ensure that it reaches its target intact’. Designing sustainable drugs could help to reduce the environmental pressure of medicines.

Hak elaborates, ‘Many different parties are involved in the chain – from pharmaceutical companies, pharmacists, and doctors to experts from water treatment plants. In the NWE region, we are working on the entire chain. We need to understand where problems arise, and then address them efficiently together’.