Variables: dissolved_organic_carbon Systems: groundwater Substances: 4-Formylaminoantipyrin (4-FAA) (WSJBSKRPKADYRQ-UHFFFAOYSA-N) 5-Fluoro Cytosine (XRECTZIEBJDKEO-UHFFFAOYSA-N) 3-5-dibromo-4-hydroxybenzoic acid (PHWAJJWKNLWZGJ-UHFFFAOYSA-N)