Garden of Invisible Poison - Domestic Soil Contamination in Nishinasuno Town, Tochigi, Japan (2003)

Garden of Invisible Poison - Domestic Soil Contamination in Nishinasuno Town, Tochigi, Japan (2003)

In the early 2000s, Japan's environmental policy was at a major turning point. While urban redevelopment and residential land development continued after the collapse of the bubble economy, land that had once housed factories and industrial facilities was rapidly being converted to residential land, and soil safety was beginning to be questioned. In the midst of this situation, a soil test conducted on an ordinary household in the town of Nishinasuno, Tochigi Prefecture, showed that these concerns were real.

In 2003, as part of its soil contamination diagnosis and remediation business, domi Kankyo, a subsidiary of Penta-Ocean Corporation, analyzed the soil of 134 residential lots and vegetable gardens requested by ordinary households mainly in the Tokyo metropolitan area. The results revealed significantly high concentrations of lead and chromium. Contamination levels considered "high" to "extremely high" were confirmed in 10% of the total samples for lead and in 14% of the samples for chromium.

As a possible cause, it was pointed out that the reclaimed soil used for land development may have been a mixture of former factory sites and waste material yards. Another factor was that construction materials generated during the demolition of old houses were not properly disposed of and remained.

The results of this survey highlighted the existence of "invisible environmental risks" lurking not in public spaces, but in private spaces. At the time, the Soil Contamination Countermeasures Law (enacted in February 2003) had just come into effect, and it was clear that the legal net had not fully extended to private homes. The law covered "specified facilities using hazardous substances," and in principle excluded ordinary residences and residential land.

This situation led to an increase in the number of individuals requesting soil diagnosis at their own risk, while the lack of administrative support and institutional supplementation became an issue. In particular, for the elderly and the child-rearing generation who are engaged in home vegetable gardening, the risk of heavy metals such as lead and chromium being taken into the body through vegetables cannot be ignored.

This case showed that Japan's "silent environmental pollution" extends to the urban periphery and residential areas, and at the same time, it raised a new public issue: how to protect the safety of the soil environment. Since then, the importance of historical management of residential land and voluntary soil analysis has been gradually recognized, and soil surveys by NPOs and community groups have gradually expanded.