制度的管理の明確化が土壌汚染対策に与えた影響

―東京都の事例―

抄録

According to market requirements for the complete removal of contamination, excavation has been frequently carried out since the enactment of the 2002 Soil Contamination Countermeasures Law. Because excavation incurs high costs and leads to brownfields, use of institutional controls (ICs) ―non-engineered instruments that limit land use to facilitate redevelopment in a faster and more cost-effective manner―at contaminated sites was introduced in the 2009 amendment. This paper estimates the impact of implementing ICs on the excavation of contaminated soil by probit model using data collected before and after implementation of the amendment. The results indicate that ICs have been selected after the law was amended for sites that do not damage human health. In terms of site characteristics, we found that the contaminated sites with higher removal costs tend to use ICs. Furthermore, contaminated sites located in central Tokyo were inclined to rely on ICs. This result implies that numerous contaminated sites in central Tokyo could be returned to their beneficial use by implementing ICs rather than by excavation of contaminated soil.