healthHealth and Medicine

Sewer Water Reveals Which Cities In Europe Take The Most Drugs


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Red light district (Wallen) on May 1, 2015, in Amsterdam, the Netherlands. lornet/Shutterstock

Just by looking for traces of drugs in sewer water, scientists can gain all kinds of insights into a city's drug use, hedonistic exploits, and all its guilty pleasures. 

A freshly published report from the EU drugs agency EMCDDA has used this inventive method to determine the patterns of drug use in 56 cities in 19 European countries, namely looking for concentrations of amphetamine, cocaine, MDMA (ecstasy), and methamphetamine in a city's wasteway. This data, combined with the area’s population and the flow of water, can provide researchers with some clues about a population’s drugs habits.


Unsurprisingly, there's a huge boom in drug use every weekend and a sharp drop in drug use every Monday.

Barcelona in Spain is the cocaine capital of Europe, according to the findings, with Zurich in Switzerland and Antwerp in Belgium closely creeping up behind. In particular, cocaine use is highest in western and southern European cities, particularly in Belgium, the Netherlands, Spain, and the UK.

When it comes to MDMA, Amsterdam tops the charts. The highest MDMA loads were consistently found in the wastewater of cities in Belgium and the Netherlands. However, the majority of cities across Europe have seen a sharp rise in the use of MDMA.

Germany is the kingdom of amphetamine, with German cities making up half of the top 10 highest users of the drug. More generally, the traces of amphetamine detected in wastewater varied considerably from city to city with no discernable pattern.


Methamphetamine use remains pretty low across the board, limited to mainly the Czech Republic and Slovakia, although it's now becoming increasingly popular throughout cities in Cyprus, Finland, Norway, and the east of Germany.

Drugs are a notoriously fickle subject to analyze. While this method is good because it’s noninvasive and allows subjects to remain anonymous, it does have some limitations that need to be considered. The EMCDDA notes that the test “cannot provide information on prevalence and frequency of use, main classes of users, and purity of the drugs.”

What's more, just because drugs are in the wastewater does not mean they were consumed by humans, it could be a by-product of manufacturing. This method is no good for detecting certain drugs, such as marijuana, the most widely used illicit substance in the world. However, the researchers say they are currently working on this problem.

All of this year's findings can also be viewed in a handy interactive mapFor comparison, you can check out the previous EMCDDA report from last year.


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