USE OF ELEMENTAL SULFUR TO ENHANCE A CADMIUM SOLUBILIZATION AND ITS VEGETATIVE REMOVAL FROM CONTAMINATED SOIL

To a soil artificially contaminated with cadmium, orthorhombic sulphur flower and a hydrophillic microbially produced elemental sulphur were added to induce the soil acidification. The soil was incubated in pot s under open-sky conditions. pH, sulphate, and cadmium solubility were recorded in time. Soil acidification with microbially produced sulphu r proceeded without any delay and at considerably higher rates, compar ed to the sulphur flower. Cadmium solubilization was solely controlled by the soil pH during the experiments. Similar experiments with culti vation of common mustard (Sinapis alba, cultivar JARA) were performed, evaluating both changes of cadmium solubilization and uptake by bioma ss. Cadmium concentration in shoots increased with decreasing pH. Howe ver, biomass was negatively affected by the decreasing pH. Combining t hese two effects, a pH-optimum for maximum cadmium removal from the so il by plants was found at pH = 5-5.5.