Fig. 7. (a) pH measured in the leachate of the second column experiment; (b–f) cumulative amounts of dissolved organic carbon (DOC), Na, Ca, Zn, and Cd leached from the columns. , no additives; , 0.1% Ca(OH)₂; +, 0.5% Ca-treated zeolite A; x, 0.5% H-treated zeolite A; –, 0.5% Ca–H-treated zeolite A.