METHOD FOR DECONTAMINATING STRUCTURE SURFACE, AND SOIL DECONTAMINATING AGENT

PROBLEM TO BE SOLVED: To provide a decontamination method and a decontaminating agent capable of inexpensively collecting contaminants such as radioactive substances for contaminated surfaces inside and outside structures such as a building and a road without causing secondary contamination.SOLUTION: The decontamination method includes: an application/gelatinization step of applying or spraying a decontaminating agent (B) containing a monovalent metal salt (A) of alginic acid and a polyvalent metal salt other than the alginic acid, on the contaminated surfaces and gelatinizing it; and a decontaminating agent removal step of removing the gelatinized decontaminating agent adsorbing and including the radioactive contaminants from the surfaces of the building or the like.