Scientists from four countries are investigating how changes in medicine prescribing and disposal can reduce pharmaceutical contamination in the Baltic Sea.

Researchers from Sweden, Finland, Lithuania, and Latvia are working to address pharmaceutical pollution in the Baltic Sea, which is considered one of the world's most polluted seas. The team argues that solving the issue requires looking beyond wastewater treatment to the entire life cycle of medicines, including how they are prescribed, used, and disposed of by patients.

Pathways of pharmaceutical contamination

Pharmaceuticals enter the Baltic Sea through various routes, including household and hospital wastewater, agricultural runoff, and discharges from production sites. According to a decade-old report by UNESCO and the Baltic Marine Environment Protection Commission, wastewater treatment plants are estimated to release approximately 1,800 tonnes of pharmaceuticals into the sea annually, as most facilities lack a fourth treatment stage for removing these pollutants.

Environmental and ecological impacts

Once in the water, some substances persist for years; for instance, the epilepsy medication carbamazepine takes nearly three and a half years to break down by half. This accumulation affects marine life, such as the Baltic blue mussel, which may have less energy for growth when exposed to painkillers. Researchers are also concerned about the potential for synthetic oestrogens to cause feminisation in fish and frogs, as well as the broader risk of antimicrobial resistance.

Strategies for reducing pollution

The research team suggests that doctors could consider environmental impacts when choosing between clinically appropriate medications. A recent study in Sweden indicated that physicians require better access to environmental data and targeted education to support this shift. Additionally, researchers are encouraging the proper return of unused medications to pharmacies to prevent them from being flushed or discarded in household waste.