FIG. 9. Breakthrough curves calculated using the Two-Site Kinetic Model for a 10-cm-long soil column and the following parameters: q = 5 cm d^–1, = 0.5, = 1 cm, K_d = 1 cm³ g^–1, and _b = 1.5 g cm^–3; on the left, f_e = 0.4 and _k = 0.1, 0.5, and 10 d^–1; and on the right, _k = 0.5 d^–1 and f_e = 0.1, 0.4, and 0.8.