DAVID JOLLY & DENISE GRADY
Even as the Japanese authorities began distributing bottled water for the estimated 80,000 children less than a year old in the Tokyo area,city authorities said Thursday that levels of a radioactive isotope found in water samples from one purification plant had fallen by more than half in the last 24 hours,now testing below the countrys stringent maximum for infants.
Continued monitoring of the situation is essential, a Tokyo government statement said,as workers tried to stave off meltdowns and radioactive emissions from a stricken nuclear plant about 140 miles north of Tokyo.
On Wednesday,the capital and two neighbouring prefectures were warned that tap water was testing at levels of iodine 131 that Japan considers unsafe for infants,though not adults. The isotope can accumulate in the thyroid and cause cancer.
Japan,with its painful legacy of atomic attack,maintains standards far more conservative than international agencies. The warning set off widespread anxiety,and a run on bottled water emptied store shelves. On Thursday morning,the authorities were considering importing bottled water.
It was not clear why the levels of iodine 131 had fallen. The authorities said that frequent rain in recent days may have washed radiation into Tokyos watershed,which lies almost entirely north and northeast of the city.
Halting progress was reported in efforts to regain control of the six reactors at the nuclear plant,Fukushima Daiichi,where cooling systems were knocked out in the earthquake and tsunami on March 11. An official of Tokyo Electric Power said workers had managed to restore lighting in the central control room of the No. 1 unit,an important step toward restarting the reactors cooling system.