From this suspect screening list, 181 unique compounds were found during screening of the river samples with an intensity above 10000 counts and at least 1 detected fragment. Figure shows the intensity trend of these compound across the samples. Overall, a higher frequency of detection of the pharmaceuticals was found in 2019 compared to 2020. The latter trend was also found in the results of the study by Singh et. al., for which the data was originally measured. In that study, the compounds were confirmed at level 1 and 2a, according to the Schymanski scheme, and in silico fragmentation was used to obtain spectra for the compounds that were missing from the MassBank of North America database. Alternatively, the match factor between the suspect entry with the best matching candidate signal can be visualized similarly. Even though no match factor filter was applied during trend analysis for the suspect screening, the occurrence frequency of likely suspects is still higher in 2019 compared to 2020. Some compounds are frequently found with high confidence for all locations and months while other are less frequent or have an overall less confident candidate. In this case the lower match factors do not completely correlate with being a more likely match, since the spectra of all database candidates for a give InChIKey were merged for setting up the suspect screening entries. This means that, for cases where many spectra where found with a variety of unique fragments, the match factor is inherently lower.