Drug consumption in German cities and municipalities during the COVID-19 lockdown: a wastewater analysis

Abstract

Purpose: Analysis of illicit drugs, medicines and pathogens in wastewater is a powerful tool for epidemiological studies to monitor public health trends. The aims of this study were to (i) assess spatial and temporal trends of population-normalized mass loads of illicit drugs and nicotine in raw wastewater in the time of regulations against SARS-CoV-2 infections (2020–21); (ii) find substances that are feasible markers for characterizing the occurrence of selected drugs in wastewater. Methods: Raw sewage 24-hour composite samples were collected in catchment areas of 15 wastewater treatment plants (WWTPs) in urban, small-town and rural areas in Germany during different lockdown phases from April 2020 to December 2021. Parent substances (amphetamine, methamphetamine, MDMA, carbamazepine, gabapentin and metoprolol) and the metabolites of cocaine (benzoylecgonine) and nicotine (cotinine) were measured. Results: The daily discharge of WWTP influents were used to calculate the daily load (mg/day) normalized by population equivalents (PE) in drained catchment areas (in mg/1,000 persons/day). An influence of the regulations to reduce SARS-CoV-2 infections such as contact bans and border closures on drug consumption has been proven in some cases and refuted in several. In addition, metoprolol and cotinine were found to be suitable as marker substances for the characterization of wastewater. A change in drug use was visible at the beginning of the Corona crisis. There after from mid-2020, no obvious effect was detected with regard to the regulations against SARS-CoV-2 infections on concentration of drugs in wastewater. Conclusions: Wastewater-based epidemiology is suitable for showing changes in drug use during the COVID-19 lockdown.