Identifying bound compounds in non-extractable residues of pesticides in soil by 4-pool kinetic analysis.

This study explores the feasibility of identifying bound compounds in non-extractable residues (NERs) of pesticides in soil by 4-pool kinetic analysis. The 4-pools refer to parent compound, metabolites, NERs, and CO in C-labeled pesticide soil degradation studies. We discovered the following two characteristic 4-pool kinetic behaviors of formation of NERs: (1) if parent compound is bound as NERs, the metabolites (m(t) in % applied radioactivity (AR)) kinetically drive the evolution of CO only; and (2) if a metabolite (x) in a sequential degradation pathway is bound as NERs, m(t) is split into m(t) and m(t) at the metabolite (x) that is bound as NERs, which kinetically drive the formation of NERs and evolution of CO respectively.