Fig. 5. The effect of immobilization treatments on Cd, Pb, and Zn phytoavailability of lettuce grown on Blackwell (BW), Henryetta (H12), and Bartlesville (B4) contaminated soils. Immobilization treatment abbreviations are the same as listed in Fig. 2. Treatments with the same letter are not different at P < 0.05 within each soil.