Wastewater and drug data analysis – a European multi-city study
The European Monitoring Center for Drugs and Drug Addiction (EMCDDA), based in Lisbon, has published a rapport which reveals levels of drug use in Europe. The data was collected by testing for the presence of illicit drugs in the wastewater of around 80 cities in 23 countries. The report's authors say it provides a valuable snapshot of the flow of drugs into the cities involved, revealing marked geographic variations.
The science of wastewater analysis is still in its infancy, having been developed in the 1990s as a tool for monitoring the environmental impact of liquid household waste. Professionals from many different scientific fields are involved in testing and analysis, such as wastewater engineering, physiology and biochemistry. Since 2011, the EMCDDA and an organization called Sewage analysis CORE Group-Europe (SCORE), have used sewage analysis to estimate the consumption of illegal drugs in Europe.
To study the drug-using habits of these communities, the scientists took samples of sewage sent to sewage treatment plants within each city tested. They screened the samples for illicit drugs by measuring the levels of metabolites excreted in urine. The tests identify the metabolites of cocaine, crack, cannabis, amphetamine, methamphetamine and MDMA, but not heroin, as its metabolite has been shown to be unstable in water.
Key findings from the 2021 study include:
The results showed distinct geographic and temporal patterns of drug use across European cities. Although levels vary from place to place, all illicit drugs are present in almost every city. Levels of the cocaine metabolite benzoylecgonine (BE) are highest in cities in western and southern Europe, and especially in cities in Belgium, the Netherlands and Spain. London has already been considered one of the European cities with the highest cocaine use, but Bristol is the only British city covered by the study. Eastern European cities had low levels of cocaine use, although cocaine use has increased in recent years. Amphetamine levels vary widely from city to city, with the highest levels recorded in northern and eastern Europe, as well as in Sweden, Belgium, the Netherlands and in Finland. This development follows the trend observed in previous years. Methamphetamine use, usually low and concentrated in Czechoslovakia and Slovakia, has been seen this year in Belgium, eastern Germany, Spain, Turkey and northern Europe. In other places, methamphetamine levels were very low or even negligible. MDMA levels have peaked in cities in Belgium, Germany, the Netherlands, Sweden and Norway. Spain, Croatia, the Netherlands and Slovenia had the highest loads of THC-COOH, a cannabis metabolite.
The study, which looks at the sewage of almost 45 million people, also found that the only drug whose consumption did not increase was MDMA, which is thought to be due to the long-term closure of the cans. night during lockdowns during COVID-19. Cannabis and cocaine use has continued on an upward curve throughout the pandemic.
Differences in levels of drugs found, and what drugs are found in the cities surveyed can be explained by many factors, including levels of prohibition and law enforcement, users' ability to obtain certain drugs, nightlife levels, student population densities and age demographics. Levels of cocaine and MDMA are generally higher in large cities than in rural areas, which is not the case for cannabis and amphetamines.
“The results show both an increase and a spread for most of the substances studied, reflecting a drug problem that is both pervasive and complex,” said Alexis Goosdeel, director of the EMCDDA.