Leaching tests of soils contaminated with heavy metal

Leaching tests were conducted for soils offered from adsorption tests to investigate the effects of solid-liquid rate, pH and procedure on dissolution of heavy metal from waste material. Adsorption is cadmium (Cd), chromium (Cr), lead (Pb) and copper (Cu) and adsorbent is Toyoura sand, glass beads, Kanuma soil, DL-clay and zeolite in the tests. The results were fitted to Freundlich isotherm mathematically expressed as exponential function with empirical two parameters, l/n and K-F. The analysis showed that the parameters determined from leaching tests coincide with that in adsorption, l/n is almost constant in a soil type while its depending on heavy metal and K-F does not depend on heavy metal but soil type when pH-change is small. Procedure was compared between batch and column tests using Cd. The study concludes that load per unit weight is available to practical index for leaching characteristics and column procedure is acceptable as availability test for assessment of heavy metal dissolved from soil.