Small amounts of radioactive material were detected in South Korea and China following radiation leaks from a crippled Japanese nuclear power plant, local media reported on Thursday.
In South Korea, traces of radioactive iodine-131 were found in an eastern coastal city in South Korea, the state-run Korea Institute of Nuclear Safety (KINS) said, according to Yonhap News Agency.
An analysis of air samples taken from 12 places nationwide Wednesday showed there were very small amounts of radioactive iodine-131 in Gangneung, 237 km east of Seoul, the KINS said, stressing that the level of concentration posed no risks to public health or the environment.
Iodine-131 is a by-product of fission reaction and poses health risks if large quantities accumulate in the thyroid gland. The material has a half-life of just 8.05 days and losses its radioactivity relatively quickly, but can be harmful for up to six months.
The institute said the radioactive element came from the crippled Fukushima nuclear power station, which began to suffer explosions on March 12.
The plant, 230 km north of Tokyo, was hit hard by the record magnitude 9.0 earthquake and tsunami on the previous day.
The detection came after the government confirmed negligible traces of radioactive xenon-133 gas in the northeastern part of South Korea on Sunday, and iodine and cesium late Monday.
It also confirmed the existence of iodine-131 in the atmosphere on Tuesday and in rain water.
In China, the National Nuclear Emergency Coordination Committee said “extremely low levels” of radioactive iodine were detected on Thursday in the air of seven more Chinese regions, including Beijing, but the materials pose no threat to public health, state-run Xinhua News Agency reported.
The committee said Wednesday that low levels of radioactive isotope iodine-131 were detected in 18 regions, including Shanghai, Tianjin and Guangdong.