Analysing drug consumption through wastewater data

The corona pandemic is over, and the consumption of cocaine is skyrocketing. This conclusion is drawn from wastewater analysis data, which estimates illicit drug consumption in European cities. The study conducted by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) is the largest of its kind. Which drugs are trending the most across 94 European cities? EMCDDA and the Europe-wide SCORE group have been collecting data since 2011. UJN media partners collected and visualised these data based on the latest results for 2023, released on March 20th. Wastewater analysis is a unique way to measure drug usage across populations since most drugs are illegal in the majority of countries.

In summary, our findings show that in 2023, the use of stimulants was on the rise, with MDMA and cocaine being the most prominent drugs used across European cities. Compared to the previous year, cocaine consumption increased in two-thirds of the monitored cities, and MDMA in more than half of them. Looking at the data for cocaine, the second most used drug in Europe, there has been an overall increase of 9.2 percent in consumption, with only 16 cities reporting a decrease in cocaine metabolites found in wastewater analysis.

This year’s highest-ranking cities—Antwerp, Tarragona, and Amsterdam—all maintained last year’s top three spots, corresponding to reports on drug confiscations in their respective countries. 

According to the most recent 2023 UN global cocaine report, Belgium and the Netherlands are currently the main European hubs for the cocaine trade. In these countries, Antwerp and Rotterdam specifically record the most cocaine seized at seaports by customs authorities. While Antwerp still records very high cocaine consumption, it decreased compared to the 2022 data. Another Belgian city, Brussels, recorded the highest decrease, with a 40 percent drop in cocaine consumption.

Significant increases in consumption, compared to the 2022 data, have occurred in central and northern Europe. Finland, Slovenia, Germany, Estonia, Sweden, and Austria are among the top 10 countries with the highest increases.

Cocaine supply hit a turning point in 2015, with cultivation mainly in countries such as Colombia increasing since then. Western and Central Europe are some of the major end markets. This year’s data show Dutch cities as major players among the top 5 and even top 10 in cocaine consumption. The Netherlands also remains a country with high levels of MDMA consumption and has the highest number of cities in the top 10: Rotterdam, Amsterdam, and Utrecht.

Apart from the top ranks, the drug’s prominence proves to be more dynamic. Except for ketamine, it has the highest increase compared to last year’s findings. The most significant increase was measured in German cities, with an overall rise of 136%. The most notable decrease was measured in Portugal, with a reduction in MDMA metabolites of nearly 60%.

Despite the Czech Republic’s reputation as a methamphetamine consumption hotspot, the numbers were relatively modest in comparison. However, usage has increased in neighbouring countries, especially in cities in eastern Germany. Experts attribute this to growing exports of meth from Czechia to other countries. Cities in these two countries together make up the top 9 spots for per capita consumption of meth, followed by Bratislava, Slovakia, in the 10th spot. Overall, methamphetamine usage in Europe has declined, most notably in the Baltic states.

On the other hand, amphetamine, also known as Speed or Pep, historically predominantly consumed in Nordic countries, seems to be distributed more evenly than in previous analyses. While there is lower prevalence in former front-runner smaller Swedish cities, there is an increase in Speed’s metabolites in Latvian, Slovenian, Belgian, and Finnish cities. Despite these changes, there is little movement in the drug’s overall popularity in Europe. The dominance of methamphetamine or amphetamine varies year to year due to the rivalry between the two drugs sharing the same market.

Cannabis has been the most widely used drug in Europe and a topic of heated political debate. Our data show that cities with the highest loads of THC-COOH, the cannabis metabolite, per capita are in the Netherlands, Spain, Slovenia, and Switzerland. Overall, the picture from the 2023 data is mixed. While consumption across all cities has risen by 8.15 percent, with the highest increases in Slovenia, Spain, the Netherlands, and Italy, cannabis use has decreased in about as many cities as it has increased.

The analysis for the year 2022 marked the first time that ketamine—an anaesthetic with some hallucinogenic effects—was measured, although for a smaller number of cities. In this year’s analysis, the newcomer has been included in measurements by more cities, indicating its relevance across Europe, predominantly in the west. Since last year, wastewater residues of ketamine have more than doubled, with Bristol, Antwerp, Rotterdam, Barcelona, and Zurich leading the chart of found residues.

The interesting insight also provides a temporal dimension: over the weekend, the consumption of recreational drugs associated with clubbing, such as MDMA, is higher in all European cities. Along with MDMA, most cities show higher residues of amphetamine, cocaine, and ketamine in wastewater during the weekend than during weekdays. This confirms that ketamine is primarily used as a recreational drug rather than for medical purposes. In contrast to weekend-heavy drugs, cannabis and methamphetamine use were found to be distributed more evenly over the whole week. Experts comment that this possibly reflects the use of these drugs being associated with more regular consumption by a cohort of high-risk users.

Another finding from the data is a flat redistribution of consumption between smaller and larger cities in the same country, challenging the stereotype of big cities being associated with increased drug consumption and showing the proliferation of drugs in all urban areas.

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