Variables: dissolved_organic_carbon total_organic_carbon Substances: 1-3-Dimethyl-2-imidazolidinon (CYSGHNMQYZDMIA-UHFFFAOYSA-N) 18-beta-Glycyrrhetinic acid (MPDGHEJMBKOTSU-YKLVYJNSSA-N) 2-4-D (OVSKIKFHRZPJSS-UHFFFAOYSA-N)