Benzene levels up to 130 times the limit set by environmental standards were detected in groundwater below the planned Toyosu food market in Tokyo in recent months, according to a Tokyo Metropolitan Government survey.
Levels of the harmful material remain elevated at the future site of the market, set to replace the aging Tsukiji site from October, although they were lower than the highest reading logged in September 2017 that reached 160 times the limit.
The metropolitan government on Wednesday reported the results of the groundwater survey for the quarter that ended in February.
Levels of arsenic and cyanogen were also found to be above environmental limits during the same period.
Air samples inside and outside the market fell within environmental limits, according to the report.
An expert panel at the metropolitan government maintains that the above-ground safety of the Toyosu market has been scientifically proven.
The metropolitan government is working to improve the quality of groundwater in the medium to long term, mainly by strengthening the market’s groundwater control system.