Abstract: A soil cleaning method (phytoremediation) of absorbing a contaminating substance contained in a contaminated soil by a plant to clean the soil. An object of the present invention is to provide a method of cleaning a contaminated soil which performs cleaning of a soil containing heavy metals in a shorter term than before and, at the same time, utilizes phytoremediation having little influence on the environment. The object is attained by absorbing heavy metals by a plant of Polygonaceae family, Fagopyrum genus, and, at the same time, adding a biodegradable chelating agent to a contaminated soil in order to assist the absorption. And, a biodegradable chelating agent having the high heavy metal dissolving out ability not only enhances the cleaning efficacy but also reduces secondary influence on the environment.

Abstract: A soil cleaning method (phytoremediation) of absorbing a contaminating substance contained in a contaminated soil by a plant to clean the soil. An object of the present invention is to provide a method of cleaning a contaminated soil which performs cleaning of a soil containing heavy metals in a shorter term than before and, at the same time, utilizes phytoremediation having little influence on the environment. The object is attained by absorbing heavy metals by a plant of Polygonaceae family, Fagopyrum genus, and, at the same time, adding a biodegradable chelating agent to a contaminated soil in order to assist the absorption. And, a biodegradable chelating agent having the high heavy metal dissolving out ability not only enhances the cleaning efficacy but also reduces secondary influence on the environment.