Fig. 2. Effect of immobilization treatments on Cd extractability in Blackwell (BW), Henryetta (H12), and Bartlesville (B4) contaminated soils as determined by the PBASE sequential extraction. LSB = lime-stabilized biosolids, NV = N-Viro Soil, RP = rock phosphate, and AB = anaerobically digested biosolids. Treatments with the same letter are not different at P < 0.05 within each soil–extract combination.