As I review the latest wastewater analysis data from across Europe, I’m struck by how much this innovative research method has evolved since its inception. What began as an experimental approach in 2011 has transformed into one of our most valuable tools for understanding drug consumption patterns across the continent.
The European Drug Analysis Agency (EUDA) released their comprehensive 2024 wastewater study last month, and I’ve spent the past three weeks poring over the data. This research now encompasses samples from over 150 wastewater treatment plants across Europe, representing approximately 50 million citizens. The scale has expanded dramatically from the initial studies, which monitored just 19 cities.
Cities – How Wastewater Analysis Works
For those unfamiliar with the methodology, wastewater-based epidemiology involves analyzing sewage water for metabolites—compounds our bodies produce after consuming substances. Scientists collect samples from wastewater treatment plants and test for specific biomarkers that indicate drug consumption in the community.
The beauty of this approach is its objectivity. Unlike surveys that rely on self-reporting, wastewater doesn’t lie. It provides near real-time data about consumption patterns across entire communities.
“This method gives us a community-wide drug test every day,” explains Dr. Helena Korvinen, lead researcher at the EUDA. “We can detect changes in consumption patterns within 24-48 hours, which is revolutionary for public health monitoring.”
Cities – Key Findings from the 2024 Study
The most recent data reveals several significant trends that haven’t yet made headlines:
Cocaine Consumption Shows North-South Gradient – Cities
The 2024 data confirms a persistent north-south gradient in cocaine use across European cities. Southern and western European cities—particularly those in Belgium, the Netherlands, Spain, and the United Kingdom—continue to show the highest concentrations of benzoylecgonine (BE), cocaine’s primary metabolite.
Antwerp, Belgium maintains its position as Europe’s cocaine capital, with average concentrations more than double that of most other European cities. This aligns with intelligence about Antwerp’s port serving as a major entry point for South American cocaine.
What’s new and noteworthy is the significant increase in cocaine metabolites detected in several Eastern European cities, particularly in Czechia and Poland, suggesting shifting trade routes or changing consumption patterns.
Methamphetamine: A Tale of Two Europes – Cities
The methamphetamine data tells one of the most interesting stories. Traditionally, this stimulant has been concentrated in Czechia, Slovakia, and eastern Germany—a pattern that persisted for decades due to local production.
However, the 2024 data reveals substantial increases in cities across Northern Europe, particularly in Finland and Norway. Several Finnish cities now show methamphetamine levels comparable to those in Prague, which has historically topped the charts.
“We’re seeing methamphetamine use expand into new territories,” notes Dr. Korvinen. “This suggests either new production sites or more efficient distribution networks.”
Cannabis Consumption: Widespread but Variable
Cannabis remains Europe’s most widely used illicit drug according to the wastewater data, with its metabolite THC-COOH detected in significant quantities across virtually all cities studied.
The highest concentrations were found in Barcelona, Amsterdam, and Zurich, with Paris showing a substantial year-over-year increase. Interestingly, cities in countries with more restrictive cannabis policies still show substantial use, reinforcing the notion that legal status has limited impact on consumption rates.
MDMA and Ketamine Show Strong Weekend Patterns
One of the most distinct patterns observed is the weekend spike in MDMA (ecstasy) levels. In cities like Amsterdam, London, and Berlin, MDMA concentrations in wastewater increase by 300-400% on weekends compared to weekdays, confirming its association with nightlife and recreational use.
Ketamine, which was added to the standard testing panel in 2020, shows similar but less pronounced weekend increases. Bristol, UK, and Amsterdam show particularly high ketamine levels, with concentrations doubling on weekends.
Geographical Insights
The expanded geographical coverage of the 2024 study provides unprecedented insights into regional variations:
Western Europe
Cities in Belgium, the Netherlands, and Switzerland consistently show high concentrations across multiple substances. Antwerp, Rotterdam, and Amsterdam remain hotspots for cocaine, MDMA, and amphetamines.
The UK presents a more varied picture, with London showing high cocaine levels but moderate MDMA use compared to Bristol, which tops the charts for ketamine.
Southern Europe
Spanish cities show high cocaine and cannabis consumption but lower levels of amphetamines and methamphetamine. Barcelona stands out with some of Europe’s highest cannabis metabolite concentrations.
Italian cities demonstrate moderate levels across most substances, though Milan shows cocaine levels comparable to those in major Western European cities.
Central and Eastern Europe
Czechia continues to show the highest methamphetamine concentrations in Europe, particularly in Prague and smaller cities. However, amphetamine is less prevalent here than in Northern Europe.
Polish cities show increasing levels of cocaine and MDMA, suggesting changing consumption patterns as economic conditions improve.
Northern Europe
Finnish cities display a surprising rise in methamphetamine concentrations, while Swedish cities show high levels of amphetamine use.
Norwegian cities, particularly Oslo, demonstrate some of Europe’s highest per-capita consumption of cocaine, challenging traditional assumptions about drug use patterns in Nordic countries.
Temporal Trends: 2011-2024
One of the most valuable aspects of the EUDA’s longitudinal data is the ability to track changes over time. Looking at the 2011-2024 dataset reveals several noteworthy trends:
Cocaine Use Continues to Rise
Cocaine concentrations have increased steadily across almost all European cities since monitoring began. The average year-over-year increase across all monitored cities is approximately 5%, though some cities have seen much larger jumps.
“The consistent upward trend in cocaine metabolites is concerning,” says Dr. Thomas Reinharz, a public health expert not involved in the study. “It suggests that supply reduction strategies have been largely ineffective in the face of abundant production in South America.”
Methamphetamine Expanding Beyond Traditional Areas
While methamphetamine was once largely confined to Czechia and neighboring regions, its footprint has expanded considerably. The Baltic states, Finland, and Cyprus have seen particularly sharp increases since 2018.
MDMA Levels Recovering After Pandemic
MDMA concentrations dropped dramatically during COVID-19 lockdowns but have now rebounded to pre-pandemic levels in most cities. In some locations, particularly Amsterdam, Berlin, and Barcelona, 2024 levels exceed those from 2019.
New Synthetic Drugs Present Monitoring Challenges
The study notes increasing detection of various synthetic cathinones and novel benzodiazepines, though quantification remains challenging due to limited reference standards and rapidly changing formulations.
Methodological Innovations
The 2024 study introduces several methodological improvements that enhance data reliability:
Improved Sampling Protocols
Researchers now implement flow-proportional sampling rather than time-proportional sampling, ensuring that samples better represent actual wastewater composition throughout the day.
Advanced Mass Spectrometry Techniques
The latest study employs high-resolution mass spectrometry, allowing detection of substances at lower concentrations and enabling retrospective analysis for newly identified compounds.
Population Biomarkers
To account for fluctuating populations, researchers now normalize data using multiple biomarkers that indicate the number of people contributing to the wastewater system, including specific pharmaceuticals and endogenous compounds.
Applications Beyond Drug Monitoring
What’s particularly exciting about this research is how the methodology is expanding beyond drugs:
Public Health Applications
The same infrastructure now monitors for COVID-19 and other pathogens, providing early warning for disease outbreaks.
“We can detect COVID-19 in wastewater up to 7 days before clinical cases appear,” explains Dr. Korvinen. “This gives public health authorities valuable time to prepare.”
Environmental Monitoring
The sampling network is increasingly being used to monitor pharmaceutical pollution, microplastics, and industrial chemicals, creating a multi-purpose surveillance system.
Alcohol and Tobacco Consumption
Several cities now regularly monitor for alcohol and nicotine metabolites, providing objective data on legal substance use that complements traditional survey methods.
Ethical and Privacy Considerations
The expanding capabilities of wastewater analysis raise important ethical questions. While the approach is non-invasive and anonymous at the individual level, it does provide intimate insights into community behaviors.
“There’s a fine line between public health surveillance and community monitoring,” notes Dr. Elena Kostova, a bioethicist I consulted for perspective. “While current applications focus on population-level patterns, the technology could potentially be deployed at smaller scales, raising privacy concerns.”
Most researchers in the field advocate for strict ethical guidelines, including transparency about monitoring activities, focus on public health applications rather than law enforcement, and community consent where possible.
The EUDA maintains that wastewater analysis complements rather than replaces traditional monitoring tools like surveys and clinical data. It provides an objective counterpoint to self-reported information but lacks the demographic and contextual detail that interview-based approaches offer.
As we look toward future developments in this field, the integration of wastewater data with other information sources—such as hospital admissions, treatment demands, and seizure data—promises to provide an increasingly comprehensive picture of substance use across Europe.
The untold story of Europe’s wastewater is that our collective consumption patterns—the medicines we take, the substances we use, and the chemicals we interact with—leave a measurable signature that flows beneath our cities every day. For researchers skilled in reading these chemical fingerprints, our wastewater has become an open book, telling stories about public health that might otherwise remain hidden.
