Fig. 3. Breakthrough curve of Cl^– (+), estradiol (o), and testosterone () through columns of conventionally tilled (CT) and no-till (NT) Cecil sandy loam. Each graph possesses two y-axes. The left y axis represents the relative concentration of hormones (C C₀^–1). The right y axis represents the relative concentration of Cl^– (C C₀^–1). Solid lines indicate the fitted model generated by HYDRUS-1D. A physical nonequilibrium model was fit to the Cl^– data and a quasi-combined physical and chemical nonequilibrium model was fit to the hormone data.