This Blog is written as of Friday, May 06, 2011
Source: REUTERS
Questions and Answers Health Risk From Troubled Japan Nuclear Plant
The following document is rewritten on my words.
Evacuation zone:
People living within the radius of 20 km (12 mile) from the plant have been evacuated, while people live in five towns placed downwind from the nuclear plant have also been told to prepare to leave their homes.
How much radiation has measured out side the evacuation zone?
The highest radiation observed outside the evacuation zone was 0.046 millisieverts an hour in Namie and Fukushima which are towns whose residents are preparing for evacuation.
In absolute terms, this figure is extremely small because people in Japan are exposed with an average of 1.5 millisieverts a year by natural background radiation.
How much exposure is dangerous?
The maximum radiation exposure of 1 millisievert per year is generally dangerous.
Can long term radiation exposure to low level radiation cause cancer?
Radiation is cumulative, and in theory, every radioactive particle that makes its way into the body increases the risk of cancer.
But there is no conclusive study that links a rise of cancer by cumulative radiation less than 100 millisieverts. Experts are divided on their policies on how these lower dosages implicate cancer.
Are some kinds of radiation more harmful than others?
Radioactive particles are most harmful when inhaled or ingested, and particles that are easily absorbed and which have longer half-lives can cause more damage to cells and genetic material inside.
Iodine-131 has a half-life of 7 days, but it accumulates quickly in the thyroid gland.
Strontium and plutonium are rarer by-products of nuclear fission. But if they are ingested, they tend to collect in bones. Strontium can cause bone cancer. Plutonium is more dangerous when inhaled.
How can we minimize the risk?
Everything depends on how good the Japanese government monitors radiation levels and how thoroughly it samples food products.
