Occurrence and Distribution of Pharmaceuticals and Their Transformation Products in Luxembourgish Surface Waters

Pharmaceuticals andtheir transformation products (TPs) are continuouslyreleased into the aquatic environment via anthropogenic activity.To expand knowledge on the presence of pharmaceuticals and their knownTPs in Luxembourgish rivers, 92 samples collected during routine monitoringevents between 2019 and 2020 were investigated using nontarget analysis.Water samples were concentrated using solid-phase extraction and thenanalyzed using liquid chromatography coupled to a high-resolutionmass spectrometer. Suspect screening was performed using several opensource computational tools and resources including Shinyscreen (https://git-r3lab.uni.lu/eci/shinyscreen/), MetFrag (https://msbi.ipb-halle.de/MetFrag/), PubChemLite (https://zenodo.org/record/4432124), and MassBank (https://massbank.eu/MassBank/). A total of 94 pharmaceuticals, 88 confirmed at a level 1 confidence(86 of which could be quantified, two compounds too low to be quantified)and six identified at level 2a, were found to be present in Luxembourgrivers. Pharmaceutical TPs (12) were also found at a level 2a confidence.The pharmaceuticals were present at median concentrations up to 214ng/L, with caffeine having a median concentration of 1424 ng/L. Antihypertensivedrugs (15), psychoactive drugs (15), and antimicrobials (eight) werethe most detected groups of pharmaceuticals. A spatiotemporal analysisof the data revealed areas with higher concentrations of the pharmaceuticals,as well as differences in pharmaceutical concentrations between 2019and 2020. The results of this work will help guide activities forimproving water management in the country and set baseline data forcontinuous monitoring and screening efforts, as well as for furtheropen data and software developments.