A case study of a large scale soil/groundwater contamination countermeasure by the volatile organic compound

摘要

Soil contamination caused by redevelopment of old factory sites has become a social problem in recent years. In order to take measures against soil contamination through grasping its extent and determining preventive procedures against health hazards, the Soil Contamination Countermeasures Act (2002 Law No.53) was put into effect in February 2003. In April 2010, the revised Soil Contamination Countermeasures Act was put into effect. On the other hand, in addition to regulatory compliance, researches have been conducted and measures taken voluntarily at the time of land transactions. In fact, the cases of such voluntary efforts are larger in number. In view of the social background, this paper discusses a case of voluntary efforts at a former textile factory site, where soil/groundwater contamination with a volatile organic compound, the First Class Specified Toxic Substance, was quite extensive but cleaned up on site within a short period of time. In the present case, mainly lime was mixed in using the Rotary Crushing Diffusive Mixing Method. It has been verified that this method effectively decontaminates the soil containing the volatile organic compound up to 77 times as much as the prescribed environmental limit, and the groundwater containing the same substance up to 4000 times as much as the prescribed environmental limit.