The residue of emerging organic pollutants in the municipal sewage wastewater has been an urgent concern for environmental health and sustainable development of water resources. There is a challenge in monitoring the occurrences of the targeted and un-targeted compounds in the wastewater, as well as their environmental fate in the natural water. In this work, ultra-high performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometry (UPLC-QToF-MS) combined with UNIFI platform was applied to screening the organic pollutants in the influent and effluent samples of a wastewater treatment plant in Xiamen during the pandemic of COVID-19 from Nov. 2021 to Ooc. 2022. The workflows were developed for the screening of three groups of chemicals: targeted compounds, post-targeted compounds, and non-targeted compounds. For the targeted and post-targeted analysis, we built a library that containing more than 1000 organic pollutants with related information on elemental composition, molecular structure, and the parameters of mass spectrometry. Screening of the un-targeted compounds was carried out by the developed statistic analysis workflow, and the molecular information was confirmed through the online database (Chemspider). We applied the workflow to the monthly wastewater samples and found 40 target and post-target substances that were frequently detected, e.g. Caffeine, Acesulfame and Amantadine. Some of the compounds were found to be related to the diagnosis of COVID-19 and flu. Un-targeted compounds that correlated with the pandemic were also identified e.g. Lauroylsarcosine and Benzokonium in the samples.

Keywords: Organic pollutants; High-resolution mass spectrometry; COVID-19