Sewage water research helps to gain a better understanding of drug use in the Netherlands. This is shown by a trial conducted by RIVM and the Trimbos Institute. The Trimbos Institute has been studying drug use in the Netherlands for years. Sewage water research can be an important supplement to this.
People who use drugs excrete the remnants through urine. This causes drug residues to enter the sewage system. RIVM investigated in twenty municipalities whether measurements in sewage water can clearly indicate how much drugs are being used.
From late 2023 to late 2024, RIVM conducted sewage water measurements at five moments for the drugs cocaine, crystal meth, XTC Ecstasy (3,4-Methylenedioxy Methamphetamine) (Ecstasy (3,4-Methylenedioxy Methamphetamine)), speed, and the designer drugs 3-CMC and 4-CMC. During each measurement, sewage water was collected over a week on multiple days at twenty sewage treatment plants. These treatment plants were located in large and small municipalities spread across the country.
Drugs in sewage water measurable in both large and small municipalities
The research shows that these drugs can be well measured in sewage water. Because the measurements were taken in both large and small municipalities across the country, the data provides a good picture of drug use throughout the Netherlands. The sewage water research showed differences in drug use between large and small municipalities. In large municipalities and cities, drug use is almost always higher, even when accounting for the larger population. The use of designer drugs is low in all municipalities studied. Therefore, differences in designer drug use between municipalities or measurement periods are difficult to detect.
Drug use remains almost constant throughout the year
The measurements also showed that the use of all drugs remained roughly constant throughout the year. Only after New Years Eve did researchers find notably more cocaine and XTC in the sewage water. The measurements also show that some drugs, such as XTC, are used more on weekends.
Annual sewage water research shows changes in drug use
The trial shows that sewage water research is a good and objective supplement to the current Trimbos research. Because drug use was roughly constant throughout the year according to the measurements, measuring once a year is sufficient to get a good picture of how much drugs are used in the Netherlands. By measuring at the same time each year, changes over the years become visible.
RIVM conducted the sewage water research on drugs on behalf of the Ministries of Health, Welfare and Sport and Justice and Security.
