ORIGINALLY PUBLISHED 11.55am GMT
Advice issued in Tokyo yesterday to avoid giving tap water to infants has been lifted after a drop in the level of iodine-131.
No effects on health would have been expected from using the water for a short time, but parents were warned by the Ministry of Health, Labour and Welfare as well as Governor of Tokyo Shintaro Ishihara to avoid giving it to children under one year of age.
That was based on measurements of radioactivity due to iodine-131 of 103, 137 and 174 becquerels per kilogram - over emergency safety indices for children, but below those for adults.
Readings today were much lower at 79 becquerels per kilogram, which has led to the advice being lifted. Ishihara thanked Tokyo residents for 'acting cool' through the alert.
Authorities mobilised bottled drinking water for 80,000 children in the city and this continues despite the ending of the alert. Levels of iodine-131 are being continuously monitored.
One factor behind the higher levels that persisted for just one day may have been widespread rain over the two preceding days. This would have brought radionuclides released from Fukushima Daiichi to ground and washed them into reservoirs.
The people most likely to be affected by releases from the plant would be those living nearest. Their evacuation started as soon as it was clear the plant was in trouble, over ten days ago. Now the evacuation zone extends to 20 kilometres with people in a further ten-kilometre zone recommended to stay indoors.
Despite unhelpful contradictory comments from some overseas nuclear regulators, the World Health Organisation backed the Japanese authorities, saying, "These recommendations are in line with those based on accepted public health expertise."
Researched and written
by World Nuclear News