The New England Journal of Medicine で 2011/04/20 に掲載された次の review article のテーブルデータをもとにしたグラフ化。
“Short-Term and Long-Term Health Risks of Nuclear-Power-Plant Accidents”
John P. Christodouleas, M.D., M.P.H., Robert D. Forrest, C.H.P., Christopher G. Ainsley, Ph.D., Zelig Tochner, M.D., Stephen M. Hahn, M.D., and Eli Glatstein, M.D.
April 20, 2011 (10.1056/NEJMra1103676)
Purpose of this Review
- put the emergency at the Japanese power plant, even as it is evolving, into the context of the extensive literature on nuclearreactor accidents by analyzing the mechanisms and major short-term and long-term health risks of radiation exposure
- briefly discuss the accidents at Three Mile Island in Pennsylvania in 1979 and at Chernobyl in Ukraine in 1986 because they illustrate the broad range of potential outcomes
Health Effects related to radiation exposure
Three Mile Island
Types of Radiation Exposure
1. total or partial body exposure
plant workers and emergency personnel who were involved in the aftermath
2. external contamination
fission products settle on human beings
polulations living near a reactor accident
3. internal contamination
fission products are ingested or inhaled or enter the body through open wounds.
This is the primary mechanism through which large populations around a reactor accident can be exposed to radiation.
注 Nuclear fission product =核分裂生成物
Chernobyl の時は様々な放射性同位体が放出されたが、その中でも問題なのが iodine-131
When iodine-131 is released, it can be inhaled or consumed after it enters the food chain, primarily through contaminated fruits, vegetables, milk, and groundwater.
Once it enters the body, iodine-131 rapidly accumulates in the thyroid gland, where it can be a source of substantial doses of beta radiation.
The release of radioactive water into the sea at the Fukushima plant has resulted in an additional route whereby the food chain may be affected, through contaminated seafood.
Although the radioactivity in seawater close to the plant may be transiently higher than usual by several orders of magnitude, it diffuses rapidly with distance and decays over time, according to half-life, both before and after ingestion by marine life.
the unit of measurement for the absorbed dose
the unit of measurement for the effective dose
Acute Radiation Sickness and Its Treatment
Increased Long-Term Cancer Risks
In the region around Chernobyl, more than 5 million people may have been exposed to excess radiation, mainly through contamination by iodine-131 and cesium isotopes.
studies evaluating leukemia and nonthyroid solid cancers have not shown consistently elevated risks in the regions around Chernobyl.
Three Mile Island
Longterm follow-up has shown no increases in cancer mortality.
thyroid cancer risks(Chernobyl)
there is strong evidence of an increased rate of secondary thyroid cancers among children who have ingested iodine-131.
Studies of the effect of thyroid exposure to radiation in utero and in adulthood have been inconclusive.
An abnormal mass of tissue that usually does not contain cysts or liquid areas. Solid tumors may be benign (not cancer), or malignant (cancer). Different types of solid tumors are named for the type of cells that form them. Examples of solid tumors are sarcomas, carcinomas, and lymphomas. Leukemias (cancers of the blood) generally do not form solid tumors.
注 utero = unborn children
In accidents in which iodine-131 is released, persons in affected areas should attempt to minimize their consumption of locally grown produce and groundwater. However, since the half-life of iodine-131 is only 8 days, these local resources should not contain substantial amounts of iodine-131 after 2 to 3 months.