US Patent 7223050 Contamination diffusion preventing structure in contaminated area

In order to effectively prevent diffusion of a harmful substance to a non-polluted soil side with a relatively simple and inexpensive construction without requiring a large-scale system, a pollution diffusion preventive wall member is installed underground for partitioning between a polluted soil side and a non-polluted soil side, the wall member being formed of wall forming material having water-permeability and containing a rare earth compound carried therein.