Fig. 8. Relationship between the concentration of leached metal in the solution and total metal content (solid) in the sludge: (a) Zn, (b) Cu, (c) Cr, (d) Pb, (e) Ni, (f) Al. Data sources: •, this study; 
, Sreekrishnan et al. (1993).
Fig. 8. Relationship between the concentration of leached metal in the solution and total metal content (solid) in the sludge: (a) Zn, (b) Cu, (c) Cr, (d) Pb, (e) Ni, (f) Al. Data sources: •, this study; , Sreekrishnan et al. (1993).