Decontamination method for soil and the like, and decontamination system for soil and the like

PROBLEM TO BE SOLVED: To provide a decontamination method for soil and the like, which surely and speedily performs decontamination of soil and water at a site of plow land and the like contaminated with a radioactive substance, and achieves volume reduction of the contaminated soil and safe processing of the radioactive substance.SOLUTION: One of, or both of contaminated soil 17 and contaminated water 4, which are decontamination targets contaminated with the radioactive substance, are collected and introduced in an elution solvent 49 so as to be eluted in the elution solvent 49, and then the radioactive substance and the decontamination targets are subjected to solid-liquid separation. Soil 17a, from which the radioactive substance is removed, is collected, and a separation liquid 37 containing the elution solvent and the contaminated water is introduced in an electrolysis tank 13 to perform electrolysis so as to allow a metal ion of the radioactive substance and the like to be deposited on a negative electrode 31. Hydrogen that contains tritium generated due to the electrolysis is caught inside the electrolysis tank 13.SELECTED DRAWING: Figure 4