Officials were able to obtain data for iodine 131 at only 400 locations, because of its short half-life of 8 days.
The latest map shows that iodine 131 spread northwest of the plant, just like cesium 137 as indicated on an earlier map.
But the substance was also confirmed south of the plant at relatively high levels.
The researchers found that accumulation levels of iodine 131 were higher than those of cesium 137 in coastal areas south of the plant.
Ministry officials say clouds that moved southward over the plant apparently caught large amounts of iodine 131 that were emitted at the time.
Iodine 131 is known to cause thyroid cancer through internal exposure. The ministry is therefore trying to determine at what levels the substance spread immediately after the accident at the plant in March.
- Japanese Researcher: Inexplicable air radiation levels infer Recriticality in July and August? (enformable.com)
- Dept. of Homeland Security-funded Study: Up to 430 pCi/liter of radioactive iodine from Fukushima found in N. California rain (CHART) (enenews.com)
- BREAKING: Iodine-131 now being detected in large amounts almost 200 km from Fukushima meltdowns (enenews.com)
- Radioactive Iodine in Sewer Sludge in Oshu City, Iwate (ex-skf.blogspot.com)
- 13% of Radioactive Iodine, 22% of Radioactive Cesium from Fukushima I Nuke Plant Landed in Central/Northern Japan (ex-skf.blogspot.com)
- Simulation shows Iodine and Cesium may have reached 15 prefectures (enformable.com)
- “Fukushima in recriticality”? – Iodine-131 detected in 4 locations: Tokyo, Iwate, Nagano, Niigata (CHARTS) (enenews.com)
- Japanese Researcher: Recriticality in July and August? (UPDATED) (ex-skf.blogspot.com)
- NHK: New estimate triples amount of radioactivity released from Fukushima reactors into sea (enenews.com)
- Ocean Contamination 3 Times As Much As TEPCO Announced (ex-skf.blogspot.com)