The breast milk of four Japanese mothers has been found to contain small quantities of radioactive iodine, prompting calls for the government to conduct a full investigation into the impact of the nuclear disaster on mothers and babies.
The contamination came to light after tests on samples from nine women living north-east or east of Tokyo.
Four were found to be contaminated, with the highest reading of 36.3 becquerels of radioactive iodine per kg detected in the milk of the mother of an eight month-old in Kashiwa, Chiba prefecture. There are no current legal safety levels for radioactive substances in breast milk as set by the Nuclear Safety Commission of Japan.
The readings were below the safety limit of 100 becquerels per kg of tap water consumption by infants under one year old.
The findings came as Naoto Kan, the prime minister, officially declared the 12-mile evacuation area around the stricken Fukushima nuclear plant a legal no-go zone rather than advisory.
Under the new order 60 families still living within the zone will be forced to leave, and entry will be strictly controlled by the authorities.
