Keywords: monitoring land use Substances: 3-5-6-Trichloro-2-pyridinol (WCYYAQFQZQEUEN-UHFFFAOYSA-N) 1-Naphthylacetic acid (PRPINYUDVPFIRX-UHFFFAOYSA-N) 4-Hydroxy-1-(2-hydroxyethyl)-2-2-6-6-tetramethylpiperidine (STEYNUVPFMIUOY-UHFFFAOYSA-N)