Variables: concentration Keywords: monitoring pesticide Substances: 2.4-D (OVSKIKFHRZPJSS-UHFFFAOYSA-N) fipronil (ZOCSXAVNDGMNBV-UHFFFAOYSA-N) mecoprop (WNTGYJSOUMFZEP-UHFFFAOYSA-N) terbutryn (IROINLKCQGIITA-UHFFFAOYSA-N)