Data Hidden in Sewage: Advanced Methods for Identification and Quantification of Synthetic Cannabinoids in Urban Wastewater

Synthetic cannabinoids (SCs) represent one of the rapidly growing groups of new psychoactive substances (NPS) on the illicit drug market. SCs mimic the effects of Δ⁹-tetrahydrocannabinol, but they have a greater affinity to the receptors, resulting in more potent psychoactive effects than traditional substances. The toxicity and high abuse potential of SCs could pose serious health risks to their users. The challenges posed by the SCs require innovative monitoring strategies like the analysis of untreated wastewater, known as wastewater-based epidemiology (WBE). In this review article, we summarized the available literature on the detection and quantification of SCs in raw wastewater samples published between 2013 and 2025. We paid special attention to challenges related to different experimental stages of WBE analysis that hinder the accurate measurement of SCs and their metabolites. The reviewed studies show that wastewater analysis reflected the dynamic evolution of the illicit SCs market. As studies on the analysis of SCs in wastewater remain scarce, large monitoring campaigns and research performed in more locations are needed. Modern analytical hyphenated systems such as LC-MS are essential for the sensitive and accurate quantification of SC biomarkers in wastewater and their sound identification. Future studies should address further stability tests, investigation of SC metabolism, and careful selection of the effective SC extraction method from the complex environmental matrix.