Fig. 5. Comparison of competition between 1,3-dichlorobenzene (DCB) and 1,2,4-trichlorobenzene (TCB) in hydrogen-ion-exchanged (H-HA) and aluminum-ion-exchanged (Al-HA) humic acids. The terms q⁰_TCB and K⁰_{d TCB} are the sorbed concentration of TCB and apparent sorbent-to-water distribution coefficient in the absence of DCB, respectively.