Variables: dissolved_organic_carbon concentration Substances: 1-(3-Chlorophenyl)-piperazin (VHFVKMTVMIZMIK-UHFFFAOYSA-N) 1-(3-Trifluoromethylphenyl)-piperazine (KKIMDKMETPPURN-UHFFFAOYSA-N) Keywords: monitoring high resolution mass spectrometry land use