European cities have a widely varied pattern of stimulant drug use, according to a study published on Wednesday.
The "Perspective on drugs" report measured drug levels found in wastewater in about 60 European cities and towns. It focused on illicit stimulants, with cannabis, for example, excluded.
The European Monitoring Centre for Drugs and Drug Addictions project measured levels of illicit drugs and their metabolites excreted in urine at wastewater treatment plants in 10 countries.
Cocaine use was found to be highest in western and southern European cities, in particular in Belgium, the Netherlands, Spain and the UK. Barcelona pipped Zurich at the top of the cocaine table. The analysis showed that cocaine use was very low to negligible in the majority of eastern European cities. Top cities: Barcelona (Spain), Zurich (Switzerland), Antwerp (Belgium).
The amount of amphetamines detected in wastewater varied considerably across study locations, with the highest levels reported in cities in the north and east of Europe, including Berlin. Their use was found at much lower levels in cities in southern Europe. Top cities: Eindhoven (Netherlands), Antwerp Zuid (Belgium), Saarbrucken (Germany).
Methamphetamine use was found to be concentrated in the east of Germany, with Chemnitz and Erfurt heading the table in Europe, followed by the Czech Republic and Slovakia. It was found also to have risen in Cyprus. The observed methamphetamine levels in other locations were very low to negligible. Top cities: Chemnitz (Germany), Erfurt (Germany), Ceske Budejovice (Czech Republic).
The highest levels of MDMA were found in the wastewater in cities in Belgium, Germany and the Netherlands. The findings showed Amsterdam heading Europe's Ecstasy table, with two other Dutch cities in the top four and the German capital, Berlin, sixth.
Longer-term trends indicated that in most cities wastewater MDMA levels were higher in 2017 than in 2011, with big increases observed in some cities, including Antwerp and Amsterdam.
MDMA prevalence was declining in many countries from peak levels in the early to mid-2000s, the report said. The report noted that this appears to be changing, with the large majority of cities reporting higher wastewater MDMA loads in 2016 or 2017 than in 2011. Top cities: Amsterdam (Netherlands), Eindhoven (Netherlands), Antwerp (Belgium).
In addition to geographical patterns, wastewater analysis is able to detect fluctuations in weekly patterns of illicit drug use. More than three-quarters of cities showed higher levels in wastewater during the weekend (Friday to Monday) than during weekdays. In contrast, amphetamine use was found to be distributed more evenly over the whole week.
Cocaine and MDMA levels were higher in large cities compared to smaller locations, the report found.