Amidst the collaborative efforts of confining radioactive materials within the underground of nuclear power plant in Japan, the radioactive iodine found a way to leak outside of Daiichi nuclear power plant, a Japanese government official announced to media on Thursday.

The contamination has spread to northwest and southern regions of the nuclear plant.

Samples of contaminated soils gathered from June to July by Japan's Ministry of Science from 2,200 locations especially in Fukushima Prefecture were adequate to produce a map to provide concrete and clear extent of radioactive contamination as of June 14.

NHK News Agency reported the government officials have encountered difficulties in obtaining iodine 131 due to its ephemeral validity of eight days. The officials only collated the samples from 400 locations from the map's 2,200 locations.

Based on the details on the map, the iodine 131 has scattered to northwest of the Daiichi Nuclear plant similar to the cesium 137 as the map suggested. However, researchers also observed the same substance has been discovered at the southern part of the plant at high levels.

Related news said iodine 131 has accumulated in levels higher than the cesium 137 in the coastal areas, southbound of the plant.

Officials of the Ministry of Science hypothesized the clouds that have moved south to the plant must have caught enormous amounts of iodine 131, which has already started to spread to plant's north direction.

Medical experts warn internal exposure to iodine 131 can cause thyroid cancer. The ministry is making efforts to ascertain the levels the radioactive material has reached after the devastating March 11 catastrophe.