Effects of Lime , Fly Ash & Rice Straw Ash on Cadmium and Lead Translocation from soil to Radish
Greenhouse pot experiments were conducted to evaluate the effects of lime, fly ash and ash(from rice straw) on the cadmium and lead translocation from soil to radish. The soils with low metal contents(Cd 1.52 ppm and Pb 25.37ppm) were prepared and high metal contents (Cd 8.99 ppm and Pb 50.81ppm) were prepared and amended with 0.25%, 0.5%, 1.0%, 2.0% each of lime, fly ash and ash. Radishes(Raphanus sativus) were cultivated and cropped on the soils during 25, 50 and 75 days after sprout, and then cadmium and lead contents of radishes were analyzed by roots and tops. The results obtained are as follows. 1. Lime and ash were effective in raising the soil pH, but fly ash was not effective. 2. The growth of radishes were not impaired by the cadmium and lead contamination but, impaired by soil pH 7.5 or more. 3. Cadmium was accumulated very strongly in radishes and the greater concentration was found in than roots, but lead showed no evidence of accumulation in radishes. 4. In general, when the concentrations of lime and ash in soils increased, the uptake of cadmium and lead by radishes decreased, and lime was more effective than ash, while fly ash revealed no effect of reducing the translocation of cadmium and lead from soils to radishes. 5. The uptake of cadmium by radishes decreased more effectively than lead and the uptake of Cd or Ph by radishes grown in the soils with high metal contents decreased more effectively than low metal con tents. 6. Cadmium and lead contents of radishes were negatively correlated with soil pH values and the relationship in cadmium content was stronger than that in lead content.