Three Doors to Revive the Memory of Soil: The Era when the True Face of Contaminated Land was Revealed Early to Late 2000s

Three Doors to Revive the Memory of Soil: The Era when the True Face of Contaminated Land was Revealed Early to Late 2000s

With the dawn of the 21st century, Japan has entered an era in which the memories of the soil that have been quietly held in the soil are being dug up all at once. Countless factories and business establishments built during Japan's period of rapid economic growth left behind a variety of chemical substances in the ground, and with the acceleration of urban redevelopment in the 2000s, these substances began to surface again. This is due to the social impact of the environmental hormone problem and the Soil Contamination Countermeasures Law that came into effect in 2002. Under this law, real estate agents who deal with land had to face the obligation to conduct surveys for the first time.

At the heart of this system was a three-phase approach, from Phase I to III. Based on the U.S. EPA's methodology and adapted for Japan, procedures were put in place to visualize, clean up, and pass on soil conditions to future generations. Phase I is the process of tracing the history of the land, investigating past uses such as factory plating operations, gas stations, etc., and reading the potential for contamination. In the 2000s, with the increase in corporate acquisitions and redevelopment, environmental due diligence became the standard for real estate transactions, and the perspective that every piece of land has a story to tell became firmly established.

In Phase II, the land is directly touched and samples are taken by borings and analyzed for heavy metals, volatile organic compounds, etc. In the mid-2008s, the land was being developed and sold in the form of trilobites. In the mid-200s, groundwater contamination by trichloroethylene became a nationwide problem, and there was a strong demand for more accurate surveys. The introduction of scientific methods, such as strata modeling and multi-point surveys for flow direction analysis, made soil evaluation more closely linked to urban planning.

Phase III represents the era of remediation and management. Various technologies such as soil washing, bioremediation, vaporization, extraction, and impervious walls were selected according to the purpose of the soil remediation. In the late 2000s, the risk-based approach was emphasized and the concept of selecting the optimal level of remediation according to the purpose of land use became widespread. Long-term monitoring after remediation took root, and companies and local communities collaborated to create a new form of environmental management.

The three phases of soil contamination countermeasures reflect the process of changing values in Japanese society beyond the framework of technological systems. Learning from the era of pollution, we must face chemical risks head-on and build a future while settling past debts in the context of urban redevelopment. These processes continue to function as a doorway to reawaken the memory of the land that had been silenced and to rebirth the city once again.