HKNIC - Health effects of Radiation
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Health effects of Radiation

Radiation can change some of the atoms in the living tissues in our bodies and affect their chemistry and therefore their functioning. Many such changes happen all the time from the radiation produced in our natural environment. Our bodies, as well as those of other living organisms, are usually capable of repairing this minor damage or even making use of the changes without any apparent ill-effects. When the radiation dose is strong, however, the affected cells are radically altered or may die. Radiation therapy makes use of this phenomenon to attack cancerous cells.

Put it in another way, when the radiation dose is low, no harmful effect can be observed, or that the consequence is so small that we cannot say whether it has any effect with a degree of certainty. However, when the radiation dose becomes larger, there are two quite different harmful effects, known as “early” and “late”.Early effects appear usually just a few days after someone is exposed to a high dose of radiation, such as that received from the explosion of a nuclear weapon or direct exposure to nuclear radiation following a severe accident associated with nuclear material. Late effects may take several years to appear, and are usually associated with lower doses of radiation, albeit still much above natural levels.

When the level of radiation is low, our bodies can cope with it just as they can cope with a small doses of toxic chemicals or a minor burn. When the radiation dosage is above 1,000 millisieverts, however, people may suffer early effects, or radiation sickness. The symptoms include loss of hair, nausea and skin burns. The severity of the symptoms will increase with the dose. Fatality becomes more frequent at higher doses and at above 10,000 millisieverts, a person will die within a few weeks.

With late effects, particularly when the radiation dose is below 1,000 millisieverts, the outcome is less certain, although development of cancer several years after the exposure is possible, with a higher risk for a higher dose. For example, someone living in an area with a high level of background radiation of 100 millisieverts may have an extra risk of 1 in 80,000 of getting cancer. That is, for every 80,000 people living in the area, one extra case of cancer may occur among them. To put this in perspective, these 80,000 people would typically experience about 200 fatal cancer cases each year.However, there is one location in Iran where the natural background radiation is reportedly above 100 millisieverts, but this apparently has no ill effects on the local inhabitants .

In practice, it is very difficult to say at precisely what level will radiation ensure no risk to human beings, since it is not practically possible to isolate the effect of low radiation doses from other possible causes of cancer, including tobacco smoke, ultra violet lights, asbestos, some chemical dyes, fungal toxins and viruses.

Radiation in Our Daily Life