The world’s waters are polluted: no news there. We’ve been living with this issue for decades, which shows little sign of abating… But if we can’t fight it, we can at least study it. Indeed, analyzing our river systems can offer valuable insights into population health. That’s the aim of the new study by the European Union Drugs Agency (EUDA), which analyzed wastewater from 115 cities in 25 countries across Europe.
This represents the most comprehensive analysis to date in wastewater research, and offers a unique glimpse into the consumption habits of different European populations.
The SCORE group (Sewage analysis CORe group — Europe) has been conducting this work since 2011, allowing researchers to compare illicit drug loads in the region over 10 consecutive years. Most of the composite samples were taken within a single week in each city, in the last case between March and May 2025. To detect the presence of various drugs, urinary biomarkers for amphetamine, methamphetamine, ketamine, and MDMA were analyzed, as well as the main urinary metabolites of cocaine and weed.
Another factor examined was variation by day of the week. For example, more than 75% of the cities showed higher concentrations of cocaine and MDMA on weekends compared to weekdays. About half of the cities showed the same pattern with ketamine. This is not the case for cannabis, amphetamine, or methamphetamine, whose use appears to be more evenly distributed throughout the week. The presence of heroin could not be accurately measured given that its specific metabolite is unstable in wastewater.
Drugs in Europe, according to wastewater
The study found a wide variation in samples across different regions, although all the illicit drugs investigated were found in almost every city. Below is a breakdown by substance, along with details of its prevalence across the European continent:
- Cocaine: Overall, cocaine levels in wastewater increased by 22% from 2024 to 2025, with higher concentrations in the south and west of the continent, particularly in Spain, the Netherlands, and Belgium.
- Ketamine: Its use appears to have risen by 41% in just one year, particularly concentrated in Germany, Belgium, and the Netherlands.
- Cannabis: No major changes in consumption were observed during the study period. The most active regions were the Netherlands, Germany, and Slovenia.
- MDMA: Once the continent’s drug of choice, Europeans appear to be moving away from ecstasy. Its use decreased by almost 16% from 2024 to 2025. However, Belgium, Spain, and the Netherlands showed the strongest signs of consumption.
- Amphetamine: It remained stable during this period, with greater evidence of use in northern European countries. The highest concentrations were seen in Norway, Sweden, Denmark, Belgium, the Netherlands, and Germany.
- Methamphetamine: It did not gain much prominence, appearing in low concentrations across the map, but in more places than a year ago. Previously predominant in the Czech Republic and Slovakia, it is now also found in Germany, Lithuania, Norway, Turkey, Spain, Cyprus, and the Netherlands.
Of course, this analysis is not without limitations. Wastewater studies, for instance, cannot determine the prevalence and frequency of drug use or on different types of users. Furthermore, as already mentioned, biomarkers can behave unpredictably in wastewater. And that’s without even considering the issue of drug purity, which is not only impossible to determine with these methods but also fluctuates unpredictably depending on time and location.
However, even if it’s not a perfect methodology (we doubt such a thing exists), this study provides valuable information on drug use trends in Europe, a region with a rich history when it comes to substance use.
Cover photo created with AI
