Tokyo Electric Power Co. on Wednesday again corrected the radiation level of groundwater samples taken from the premises of the crippled Fukushima Daiichi nuclear complex, saying it was a tenth of the level announced earlier this month.
It is the second time that the utility has corrected the data regarding groundwater, part of which TEPCO is seeking to dump in the Pacific Ocean after confirming that concentrations of radioactive substances are sufficiently low.
The utility said in May that radioactive cesium in the groundwater was at a level that could not be detected by an instrument at the Fukushima plant, but on June 3 TEPCO said the sample contained 0.61 becquerel of radioactive cesium per liter.
On Wednesday, however, TEPCO said that a maximum of 0.055 becquerel of cesium had been detected.
All of the figures are below the threshold that TEPCO views as the upper limit for releasing groundwater, which is less than one becquerel per liter.
But the latest development could deal another blow to TEPCO as the utility is trying to get the nod from local fishermen to discharge groundwater that would otherwise flow into reactor buildings and become highly contaminated with radioactive substances.
A massive amount of radioactive water is accumulating at the plant as a result of continuing water injections into the three reactors that have suffered meltdowns. Groundwater penetration is also leading to an increase in the total amount of polluted water.