Wastewater analyses reveal drug habits in European cities

The findings of the largest European project to date in the emerging science of wastewater analysis (WWA) are released today in an article published in the journal Addiction.

The project in question – steered by the Europe-wide SCORE network – analysed wastewater in over 40 European cities to explore the drug-taking habits of the general population.

The study’s conclusions are taken up in the European Drug Report 2014, launched by the EU drugs agency (EMCDDA) today, as well as in an online interactive analysis by the agency dedicated to the issue Perspectives on drugs.

Assess geographical differences and temporal changes in illicit drug use

The purpose of the study was to assess geographical differences and temporal changes in illicit drug use in metropolitan settings across the region.

It is the first, and most extensive, WWA application to date, covering multiple countries, over consecutive years (2011–13) and according to a common protocol.

Wastewater analysis is a rapidly developing and novel scientific discipline with the potential for monitoring near-real-time population-level trends in illicit drug use.

By sampling a known source of wastewater, such as a sewage influent to a wastewater treatment plant (WWTP), scientists can now estimate the quantity of drugs used in a community by measuring the levels of illicit drugs and their metabolites excreted in urine.

From London to Nicosia and Oslo to Lisbon, the study analysed daily wastewater samples in the catchment areas of WWTPs over a one-week period in April 2012 and in March 2013.

In 2012, the study involved 23 cities in 11 countries, while in 2013 it was broadened to 42 cities in 21 countries. Data from a 2011 study (19 cities, 11 countries) were used for comparison. 

Several kinds of drugs

Wastewater from approximately 8 million people was analysed for traces of five illicit drugs: amphetamine, cannabis, cocaine, ecstasy and methamphetamine.

The WWA results provide a valuable snapshot of the drug flow through the cities involved, revealing marked regional variations in drug use patterns.

Trace of cocaine, for example, were higher in western and some southern cities but lower in northern and eastern cities.

Use of amphetamine, while relatively evenly distributed, showed the highest levels in the north and northwest of Europe.

Methamphetamine use, generally low and traditionally concentrated in the Czech Republic and Slovakia, now appears to be present in eastern Germany and northern Europe.

Weekly patterns of drug use were also examined – and results confirm cocaine and ecstasy levels rise sharply at weekends in most cities, while methamphetamine and cannabis use appears to be more evenly distributed throughout the week.

Some findings from Oslo's wastewater:

• Oslo is below the European average for cocaine use, although a significant increase was seen between 2011 and 2012.
• A significant increase in amphetamine use between 2011 and 2013, taking Norway from below to over the European average.
• A significant reduction in methamphetamine use between 2011 and 2013, although outside of the Czech Republic, Slovakia and Eastern Germany, Oslo is still has a high level of use compared to other countries.
• MDMA use is below the European average with no significant change.
• Cannabis levels were just above the European average with Oslo ranked 10th of 44 cities.

Wastewater analysis provides the possibility to collect and report measurements more quickly and regularly than is the current norm for national surveys, concludes the report.

If used more routinely as a complement to other European drug surveillance methods, WWA has the clear potential to shed extra light on drug use trends in Europe, including the use of new psychoactive substances.

SCORE is chaired by Dr. Kevin Thomas, research manager at The Norwegian Institute for Water Research (NIVA).

External links

• Spatial differences and temporal changes in illicit drug use in Europe quantified by wastewater analysis’, Addiction 109: doi: 10.1111/add.12570. (Abstract)
• FAQ Wastewater analysis (NIVA)
• Kevin Thomas' profile