Influent wastewater analysis to investigate emerging trends of new psychoactive substances use in Europe

New psychoactive substances (NPS) show up in wastewater, and wastewater-based epidemiology (WBE) can track emerging drug trends across time and cities. This study analyzes influent wastewater from 12 European cities across March to June 2021 to measure more than 300 NPS plus fentanyl and norfentanyl. The researchers use solid phase extraction and liquid chromatography-mass spectrometry with both quantitative analysis and suspect screening, then test which drug biomarkers remain stable in-sample under storage conditions. Results show fentanyl, norfentanyl, and 15 additional NPS can be detected, with at least three NPS present in each city. N,N-dimethyltryptamine and 3-methylmethcathinone (3-MMC) are among the most common NPS, with the highest mass loads observed for 3-MMC and a changing weekly use profile for 3-MMC. The work positions WBE as a complementary early-warning tool alongside surveys, seizures, and other indicators for public health protection.