Monitoring Illicit Drugs and New Psychoactive Substances in Urban Wastewater of Konya Using LC-MS/MS: A Prospective Pilot Study

Aim: This study aimed to identify illicit drugs and new psychoactive substances in wastewater reaching a treatment plant in Konya, quantify their concentrations using high-sensitivity analytical methods, and provide preliminary data on their occurrence and temporal distribution.Materials and Methods: Throughout August 2025, 24-hour composite wastewater samples (n=12) were collected on predefined routine sampling days from a wastewater treatment plant in Konya. Samples were pre-concentrated using solid-phase extraction, quantitatively analyzed by LC-MS/MS, and positive findings were confirmed using high-resolution Orbitrap LC-MS. Analyses were conducted in accordance with validated institutional protocols following internal standard correction.Results: Reliable quantitative results were obtained for 10 analytes detected in wastewater samples. The number of analytes identified per sample ranged from one to nine. Pharmaceutical compounds were detected in all or most samples, whereas indicators of illicit drugs and psychoactive substances were observed only on a limited number of sampling days. Heat-map analysis demonstrated that methamphetamine, MDMB-BUTINACA, and benzoylecgonine exhibited discontinuous temporal patterns restricted to specific days.Conclusions: The findings of this prospective pilot study suggest that wastewater-based epidemiology may serve as a feasible approach for monitoring the occurrence and temporal distribution of illicit drugs and new psychoactive substances in urban wastewater. Monitoring strategies incorporating increased sampling frequency and normalization using flow and population data may improve the reliability and comparability of temporal assessments.