Abstract
A study on behaviors of iron, sulfur and trace metals, such as cadmium, zinc and lead in the weathering process of pyrite-bearing shale and surface soil was conducted by observing the changes of their contents in the rock and soil under the oxidation conditions. The contents of iron, sulfur and lead in the soil were found to decrease, however, that of zinc to increase and taht of cadmium to remain unchange.
These results suggest that sulfur is released from the rock as soluble sulfate ion due t o the dissolution of pyrite, and that irons are partly released as soluble ion (II), but the rest remain in the soil as unsoluble ion oxides. The adsorptivity order of the tracs metals on/into the original and/or secondary minerals on weathering is zinc > cadmium > lead. The adsorptivity of trace metals seems to depend on the ionic radius of the metals, that is, the smaller radius, the more affinity of the metal to the minerals. However, behaviors of trace metals are too complicate to be explained only by the ionic radius.
