Sewage analysis shows London to be the cocaine capital of Europe (on weekdays, anyway)
There are many ways of measuring drug use, but at a population level, it all becomes a bit tricky. Illegal substances by their very nature tend to have a stigma attached, meaning that surveys suffer from (understandable) dishonesty. You can track other indicators such as street value (giving you an idea of supply and demand), hospitalisations and arrest information, but for obvious reasons this only gives you a ballpark figure. And while cocaine remains illegal, you won’t see drug dealers’ Q4 figures being published any time soon.
One interesting way around this is to measure the contents of our sewers. Wastewater analysis is a surprisingly effective way of testing what illegal substances have gone through a population’s bodies, and in what kind of quantities.
Take cocaine, for example…. Wait, let me rephrase that. Let’s use cocaine as an example. When the body breaks down cocaine, the drug is metabolised into a number of things: chiefly benzoylecgonine. By taking wastewater samples from the treatment plant before it’s treated, scientists from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) were able to measure cocaine use across 50 European cities in a week in March 2016 – once population sizes were taken into account.
This interactive map shows their findings, not just for cocaine, but for amphetamines, methamphetamines and MDMA. When you dig down into the raw stats, it becomes pretty clear that London is a big fan of the white stuff, topping the weekday-usage chart with 790mg per thousand people per day. On the weekend, though, it’s a different story, and although Londoner usage rises to 999.3mg per thousand, Britain’s capital is eclipsed by Antwerp in Belgium, where the rate is a huge 1,042mg per thousand. Other European capitals, by contrast, are much less fond of the drug: Lisbon recorded 274.5mg, Paris 197.3mg, Oslo 164.4mg, Athens 34.3mg and Helsinki 20.4mg.
Elsewhere, methamphetamine usage seems to be migrating across Europe from its traditional high points in the Czech Republic and Slovakia, and while other drugs tend to spike on the weekend, meth use seems pretty consistent throughout the entire week.
The data also reveals that MDMA usage has significantly increased across Europe in the past five years, which is useful to know with regards to education programmes and so forth. However, because of the way the data was measured, this might suggest increased purity rather than more people consuming the drug.
That’s one issue with this form of measurement, and there are others (people may not release the drugs from their body in the same location they put them into their body), but it’s still very useful information to have – especially given that, unlike sociological data, this information is close to real-time.
“Wastewater-based epidemiology has demonstrated its potential to become a useful complement to established drug-monitoring tools. Its ability to deliver timely data on drug-use patterns is particularly relevant against the backdrop of an ever-shifting drugs problem,” said Alexis Goosdeel, director of EMCDDA. “By detecting changes in drug-use patterns, both geographically and over time, it can help health and treatment services respond better to emerging trends and changing treatment needs.”
Image: Pedro Szekely used under Creative Commons