Patterns of drug use and chemical exposure in Athens (Greece) during COVID-19 pandemic using wastewater-based epidemiology
After the first COVID-19 case in 2019 in Wuhan, China, the virus SARS-COV-2 has rapidly spread nationwide, alarming both the public and scientific community (Cascella et al., 2021). Currently, there are no treatments available for COVID-19, hence reducing the virus transmission and vaccinations are the key strategies for the management of the pandemic. Countries around the globe, including Greece, have already implemented such containment measures (Yuki et al., 2020, Parlapani et al., 2020). The pandemic, in combination with strict restriction policies in all aspects of human activity, may considerably affect human lifestyle, behavior and mental health. As a result, changes in drug consumption and other chemicals’ use are highly likely to occur. Wastewater-Based Epidemiology (WBE), is a continuously growing field for the quantification of analytes in wastewater samples. WBE uses biomarkers, which reflect a populations’ health status and elaborate on pathogen and substance exposure and consumption (Choi et al., 2018). Offering great sensitivity and selectivity (Diaz et al., 2012), LC-MS, is the most widely used analytical technique for the application of WBE. TOF mass spectrometers on the other hand exhibit intrinsic characteristics, such as extra selectivity and retrospective analysis (Alygizakis et al., 2020). Hence, they are ideal for wide-scope target screening strategies, as well as for transformation products (TPs) identification, including unknowns (Hernandez et al., 2012, Nika et al., 2017). The objective of this study was to investigate and reflect the potential effects of COVID-19 pandemic in drug consumption and chemicals’ use, through influent wastewater analysis. The focus of this study was given during the 2020-2021 lockdown period in Athens, Greece. For this purpose, untreated wastewater was sampled during representative periods before and during quarantine. Samples were analyzed by two complementary analytical methods; a highly-sensitive LC-MS/MS method (Gago-Ferrero et al., 2015) and a generic and wide-scope LC-ESI-QTOF-MS method (Gago-Ferrero et al., 2020). Target screening of pharmaceuticals and drugs of abuse was performed with LC-MS/MS. Concerning the HRMS analysis, both wide-scope target and non-target screening methodologies were applied for the detection of the analytes of interest and their respective transformation products (TPs). The detected concentrations were back-calculated into normalized population loads (PNLs), based on parameters such as flow rate, population estimation etc (Thomaidis et al., 2016). The results reflected patterns in various chemicals’ use (e.g. pharmaceuticals, illicit drugs, antimicrobials, surfactants etc.), some of which can be closely attributed to the impact of COVID-19 pandemic on the population.