Variables: total_organic_carbon Keywords: land use Substances: 4-Formylaminoantipyrin (4-FAA) (WSJBSKRPKADYRQ-UHFFFAOYSA-N) Acetochlor-ESA (HXAIQOCRALNGKB-UHFFFAOYSA-N) 3-5-Diamino-2-4-6-triiodobenzoic acid (GOQCZMZLABPEME-UHFFFAOYSA-N)