The Yomiuri Shimbun The Toyosu wholesale market is “scientifically and legally safe,” according to the head of a panel of experts commissioned by the Tokyo metropolitan government to discuss the safety of the market.
Tatemasa Hirata, chief of the Open University of Wakayama Study Center, expressed the panel’s view during a Sunday meeting. The panel reported during the meeting that a recent survey, the 10th to be conducted, had found benzene at a level 100 times higher than the government-set environmental standard in groundwater samples from the Toyosu market.
In response to the latest survey, Tokyo Gov. Yuriko Koike will decide whether to transfer the market to the Toyosu area from its current location in Tsukiji.
Groundwater samples were taken at 27 locations, many of which were places where higher levels of toxic substances were detected in the ninth survey than in the preceding eight surveys. Four research institutes analyzed the samples.
Toxic chemicals exceeded the environmental standards at 25 locations. Benzene was detected at 22 locations, among which the levels were above the government-set environmental limit at 19 locations.
At a place where benzene was 79 times higher than the standard in the ninth survey, the levels increased to 80 to 100 times higher in the latest survey.
Arsenic was detected at six locations, of which five showed levels up to 3.6 times higher than the standard.
The samples also contained the banned substance cyanogen at 22 locations. Of this number, above-standard levels of cyanogen were found at 18 locations.
There were some cases in which multiple chemicals exceeded their limits in the same locations.
As to why the ninth survey showed a rapid increase in the number of locations with excessive levels of chemicals, the panel cited the operation of a system that maintains a constant water level by pumping groundwater.
The system was in partial operation before the eighth survey, and operated at full capacity before the ninth survey. The panel therefore presumed that as the operation of the system changed the flow of the groundwater, pollutants that remained in specific areas may have moved to other places.
In addition, because polluted soil resulting from Tokyo Gas Co. factories has been almost completely removed and there is no risk of people coming into contact with the contaminated soil, the panel judged that safety has been maintained from both a legal and scientific standpoint.
The environmental standard for groundwater was set on the assumption of drinking two liters every day for 70 years. The groundwater at the Toyosu market will not be used for purposes such as drinking.
“It is necessary to consider safety by separating above-ground and underground water,” the chairman of the panel said.
As measures to be taken in the future, the panel proposed strengthening the groundwater management system to prevent a rise in the groundwater level, and installing ventilating equipment to prevent toxic vapors in the underground space of the market from spreading to other places.
Koike will refer to the panel’s opinions when deciding whether to transfer the Tsukiji market to the Toyosu area.
“We have to seriously consider the fact that the groundwater samples contained toxic substances that exceeded the [environmental] standards,” Koike told reporters Sunday.
However, she avoided a specific comment on the future schedule for the transfer, saying only, “Meetings of the expert panel and the investigative committee [established by the metropolitan assembly] will be held, so it’s still too early to make a decision.”Speech