Pollution data on market site 'hidden'

The Yomiuri Shimbun

The Tokyo metropolitan government concealed data concerning soil pollution at the planned relocation site for the Tsukiji fish market when it announced in March the results of test efforts to remove toxic chemicals from the ground at the planned site in Toyosu in Koto Ward, Tokyo, The Yomiuri Shimbun has learned.

In March, the metropolitan government announced that it had successfully detoxified soil that had contained benzene at levels 43,000 times greater than environmental safety standards through an experimental cleanup.

However, sources said the parts of the site on which the government conducted the experiment originally contained a benzene level just 2.7 times higher than environmental safety standards when the government started the experimental cleanup--much less than the 43,000 figure.

Meanwhile, the metropolitan government also said it had detoxified soil of arsenic at another part of the site, but even before the experimental cleanup, the location contained arsenic at a level lower than environmental safety standards, the sources said.

However, the metropolitan government has never published the complete data.

As the Tsukiji market's planned relocation site was found to be highly contaminated, the metropolitan government has been examining measures to eliminate toxic materials. After the examination is finished, the government plans to start a soil cleanup project for which it has earmarked 58.6 billion yen, aiming to open the new Tsukiji market in 2014.

In March, the metropolitan government announced an interim report on the cleanup experiments. At that time, the Tokyo Metropolitan Assembly was discussing budgets totaling about 128.1 billion yen for the transfer of the market and other related issues.

Several senior government officials say that the metropolitan government had feared that if it had announced lower contamination levels at the test spots than were originally announced for other parts of the site, it might have led to questions over the effectiveness of the cleanup experiments, leading to confusion in the assembly.

The latest revelation likely will cast doubt on the metropolitan government's standards of information disclosure.

At the planned relocation site, benzene at a level 43,000 times above the environmental safety standard was detected in the soil in 2008. The discovery of the soil pollution led opposition parties in the assembly, including the Democratic Party of Japan, to intensify their criticism of the planned relocation.

Due to that, the metropolitan government started experiments in January to show the effectiveness of measures to eliminate soil pollution. On the about 400,000-square-meter relocation site, the metropolitan government took soil and groundwater samples from 16 locations and detoxified them using heat treatment and other techniques.

On March 10, the metropolitan government announced that it had successfully reduced the levels of toxic materials to within environmental safety standards at five locations, including one that had contained a benzene level 43,000 times higher than the safety standards.

However, the location that the metropolitan government said it had been able to detoxify from a level of 43,000 times the environmental safety standards had actually contained a benzene level just 2.7 times the standards.

Under the standards, a safe level of benzene is considered to be no more than 0.01 milligram per liter of soil.

Arsenic was another contaminant targeted by the experiment. But at a location where arsenic had been detected at a level 3.4 times higher than the standards in the 2008 survey, the arsenic level was found to be lower than the standards at the time when the experiment started this year.

Meanwhile, the budget for the relocation of the Tsukiji fish market was approved on March 30.

"We planned to announce the true data eventually. We didn't mean to cover up the facts," a metropolitan government official said.

"The experimental methods that the metropolitan government had used were appropriate, but it's common sense in science to show data as they are," said Prof. Masaaki Hosomi of the Tokyo University of Agriculture and Technology's Graduate School of Engineering Department of Applied Chemistry. "The government's explanation makes it sound like it could detoxify soil highly contaminated with benzene. Such an explanation will lead to misunderstanding and also prompt questions over the reliability of the experiments."