Variables: dissolved_oygen electric_conductivity concentration Keywords: high resolution mass spectrometry Systems: groundwater Substances: 1-(3-Chlorophenyl)-piperazin (VHFVKMTVMIZMIK-UHFFFAOYSA-N) 2 -2 -Difluorodeoxyuridin (FIRDBEQIJQERSE-QPPQHZFASA-N)