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Wastewater Analysis Reveals Which Drugs People Have Been Using During Lockdown


Ben Taub

Freelance Writer

clockMay 19 2021, 12:32 UTC

Residues of cannabis, cocaine, MDMA, amphetamine and methamphetamine were found in sewage across Europe. Image: New Africa/

An analysis of untreated sewage from 82 cities across Europe indicates that people in Belgium, Croatia, and the Netherlands consumed the most illicit drugs during the first wave of COVID-19 lockdowns. Collected between March and May 2020, the samples were analyzed for traces of MDMA, amphetamine and methamphetamine, as well as metabolites of cocaine and cannabis.

Conducted by the European Monitoring Centre for Drugs and Drug Addiction, the wastewater analysis project is now in its tenth year, and data from the latest edition makes for interesting reading when compared to previous findings. For example, the closure of nightlife venues has upset trends in MDMA use, which is primarily consumed as a party drug.

As a consequence, the prevalence of MDMA in wastewater dropped in around half of the testing locations when compared to 2019 levels. Overall, the Netherlands remained the continent’s top consumer of MDMA, with the highest levels found in Amsterdam and Utrecht.


Cocaine use, meanwhile, has been steadily rising across Europe for several years, as evidenced by increasing concentrations of its main metabolite, benzoylecgonine (BE), in wastewater. The average level of BE detected in all testing sites for which data is available for each of the past ten years rose from 306.71 milligrams per 1,000 people in 2011 to 570.3 milligrams per 1,000 people in 2020.

However, of the 49 sites for which data is available for both 2019 and 2020, 16 reported a decrease in cocaine use, indicating that the pandemic may have disrupted the general trend. Overall, cocaine is most prevalent in western Europe, with Antwerp and Zurich being the highest consumers of the drug last year.

Perhaps unsurprisingly, wastewater levels of both MDMA and cocaine were higher in all locations at the weekend than on weekdays, suggesting that people generally use these substances when they don’t have to work the next day.


To analyze trends in cannabis use, the researchers looked for a metabolite called 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH). Unlike other drugs, cannabis appeared to be unaffected by the pandemic, with use remaining high across Europe. In 2020, the highest wastewater levels of THC-COOH were found in Amsterdam and Zagreb, followed by Geneva and Paris.

Amphetamine use was generally restricted to the north and east of the continent, with Zagreb in Croatia and Gävle in Sweden being the top consumers, while methamphetamine was most prevalent in Czechia and Germany.

With the exception of cannabis and amphetamine, all drugs were found to be more prevalent in large cities than in small towns or rural locations. Cannabis use was also constant throughout the week, with no variation seen between weekdays and the weekend.




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