fig4

Figure 4. Mean concentrations of IBU and its metabolites as a function of time in (A) sludge-amended soil and (B) compost-amended soil and curves of the applied kinetic models. BEM: Bi-exponential model; CBX-IBU: carboxy-ibuprofen; FODED: first-order double-exponential decay; FOTC: first-order two-compartment; IBU: Ibuprofen; LM: logistic model; MHSM: modified hockey-stick model; SFO: a single first-order; 1-OH-IBU: 1-hydroxyibuprofen; 2-OH-IBU: 2-hydroxyibuprofen.