Fig. 1. Results of equilibrium experiments Batch-1 (a–c) and Batch-2 (d–f). In Batch-1, acid or base was added to Soil A and Soil C. In Batch-2, AlCl₃ was added to Soil A and Soil C. Soil A has a higher Al content than Soil C. Open symbols represent observations for Soil C, and closed symbols for Soil A. Lines are WHAM simulations (dotted is Soil C; solid is Soil A). Note that the Y-axis for Al-qr is different for Batch-1 and Batch-2. Error bars show standard errors.