Abstract
To evaluate the suppressive effect of five additives on cadmium (Cd) uptake by komatsuna (Brassica rapa var. perviridis cv. Early komatsuna), a pot experiment with Cd-contaminated acidic soil was conducted in a greenhouse. Autoclaved lightweight aerated concrete (ALC), lherzolite (Lherzo), gypsum made from waste plasterboard (Gyp-w), magnesia cement (Magwhite) and calcium carbonate containing less than 10 % pure gypsum (Cacar-G) were added to the soil (1 %, w / v). The shoot Cd concentration of the plants was considerably suppressed by the application of Cacar-G and Magwhite, following by ALC moderately, Lherzo and Gyp-w slightly. The order was similar to that of the additives which increased the soil pH. In addition, the order except Gyp-w was in agreement with that of the additives which decreased the exchangeable Cd concentration in the soil. Gyp-w increased the water-soluble Cd concentration in the soil. We presumed that the Cd uptake of the plants might be controlled by the soil pH and the level of water-soluble and exchangeable Cd. It is concluded that Cacar-G and Magwhite are considerably effective soil amendments in the suppression of the Cd uptake by the plants; ALC is moderately effective, whereas Lherzo and Gyp-w are scarcely effective when they are added at 1 % concentration to the soil.
