Wastewater-based studies provide independent information on drug use occurring within the sewerage area almost in real time. This approach offers a unique way to study population-level drug use, which is otherwise difficult to investigate. Improved analytical methods have also yielded promising results in monitoring phenomena such as the emergence of new psychoactive substances.
Finnish Institute for Health and Welfare's (THL) national wastewater research currently covers over 60% of Finland’s population. Several key changes in Finland’s drug situation have first been detected through longitudinal monitoring in the Helsinki metropolitan area.
Finland's situation is assessed by comparing it to international trends as part of the European Union Drugs Agency (EUDA) coordinated network. THL also participates in the EU-WISH international project, which aims to strengthen EU countries' ability to prevent, prepare for, and respond to serious cross-border health threats.
Goals
- Produce data on the regional prevalence of drug use and changes over time.
- Combine wastewater-based population-level data with other research and registry data for a comprehensive picture of the drug situation.
- Enable early detection of major changes through near real-time monitoring.
- Support decision-making at regional, national, and international levels and inform measures to prevent substance-related harm.
Implementation
The national wastewater research covers over 60% of Finland’s population. Sampling is conducted during collection weeks in March and November by taking seven consecutive 24-hour composite samples of untreated wastewater at treatment plants. Average results are used to calculate drug consumption in each plant’s service area.
Drug use is measured every two years in 30 cities and surrounding areas. Since 2012, Helsinki, Espoo, Lahti, Turku, Tampere, Jyväskylä, Lappeenranta, Kuopio, Oulu, and Rovaniemi have participated. Additional cities have been added over time, including Kotka, Joensuu, Vaasa, Savonlinna in the year 2014, Kouvola, Hämeenlinna, Pori, Mikkeli, Seinäjoki, Kokkola, Kajaani, Kemi, and Mariehamn in 2018, Rauma, Pietarsaari, Salo, Vihti in 2020, and Porvoo, Huittinen, Jämsä in 2024. Four major plants (Helsinki, Espoo, Turku, Tampere) also collect samples in odd years. Continuous monitoring every two weeks at Helsinki, Turku, and Tampere reflects weekend substance use.
Statistics on population-level drug use by region
Funding
National monitoring is funded through the state budget. The European Drugs Agency (EUDA) supports Europe‑wide monitoring, for which national results are used. Wastewater research has had several externally funded projects related to the development of monitoring and preparedness.
Partners
- Wastewater treatment plants in research cities
- SCORE network
- European Union Drugs Agency (EUDA)
- United Nations Office for Drugs and Crime (UNODC)
Contact details
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