[Occurrence of Tramadol and Fentanyl Use in Domestic Wastewater in Beijing].

Tramadol (TRA) and fentanyl (FEN) are used as common painkillers in clinical practice, but they have been increasingly abused in recent years due to their addictive nature. Two substances and their metabolites enter wastewater through urine and are collected and treated by wastewater treatment plants (WWTPs) before being discharged into the aquatic environment. In this study, wastewater analysis was performed to examine the patterns of TRA and FEN use in the urban area of Beijing for the first time. Influent and effluent samples were collected from 23 WWTPs during two sampling campaigns. Concentrations TRA in influents were found to range from(10.2±8.7)to(175.3±59.7) ng·L-1, while FEN was not detected in most of the samples, or occurred at very low concentrations. Relatively low TRA removal was observed at plants with activated sludge processes. Moreover, TRA loads in the central area of Beijing were significantly higher than those in the suburban areas. Annual TRA use was estimated through wastewater-based epidemiology. The greatest TRA use, approximately 202.5 kg, was found in Haidian district. Seasonal variation in TRA loads was significant, with greater use in the summer than in winter. The method presented in this study can be used as an important reference for monitoring TRA and FEN use via wastewater-based epidemiology and for assessing the risk of the abuse of these compounds in China.

[Optimization and Validation of the Analytical Method to Detect New Psychoactive Substances in Wastewater].

New psychoactive substances (NPS) are emerging continuously, as the crackdown against traditional drugs becomes stricter. Metabolites of NPSs and the unchanged drugs enter wastewater through urine and are collected and treated by wastewater treatment plants before being discharged into the aquatic environment. Based on previous research, solid phase extraction (SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) were used and the detection method of 11 NPSs was optimized. Influences of wastewater pretreatment procedures, including SPE columns; pH values of water samples; and processes of flushing and redissolving on NPS recoveries were compared. It was shown that the best recovery was achieved when Oasis MCX columns were used and the pH value of wastewater samples was adjusted to 2. A flushing process with 2 mL water at pH=2 followed by 2 mL methanol was needed. Redissolution of the residue after evaporation was best achieved with 400 µL of a 20% methanol water solution. It was indicated by retention times, recoveries, matrix effects, limits of detection, limits of quantification, as well as precision that C18-UPLC-MS/MS and the optimized method are efficient and valid. Influent and effluent samples from 11 municipal wastewater treatment plants in Beijing were analyzed using the optimized method for validation. The validated method can be used as an important reference for monitoring NPSs via wastewater-based epidemiology and for assessing the risk of NPS abuse in China.