Acute and Chronic Dangers of Excessive Radiation

There's been quite a bit of fear about radiation exposure due to the recent nuclear disaster in Japan. This has apparently caused folks on the West Coast of the U.S. to experience some panic about their risk for thyroid cancer and has led to their taking potassium iodide tablets.  In fact, people on the West Coast are not facing an increased risk of thyroid cancer at this time. And by taking large amounts of iodine, people over the age of 40 may develop an underactive thyroid gland (hypothyroidism). The key word here is "excessive" exposure. 

Acute effects: radiation poisoning or sickness

The dose of radiation exposure determines the type of symptoms and the time of their onset. Even relatively low doses of radiation may be accompanied by the rapid onset of nausea, vomiting, skin reddening, tiredness, and fever. Larger doses can cause rapid death. Intermediate amounts of exposure can result in the symptoms of radiation sickness over a period of several months. These symptoms result from:

• Bone marrow damage which leads to infections from low white blood cells, bleeding from low blood platelets, and tiredness from decreased red blood cells.
• Damage to the gastrointestinal tract may cause nausea, vomiting, abdominal pain, and loss of appetite.
• Effects on the nervous system which include diminished consciousness, headache, and dizziness.
• Skin irradiation leads to extreme reddening, blisters, and ulceration. 

Supportive measures, such as blood transfusions and antibiotics, are the only treatment options for radiation sickness.

Chronic effects of lower doses of radiation

Exposure to radiation can produce genetic damage and increase the risk of both malignant and benign tumors.  Except for avoiding radiation exposure, the only possible preventive measure is to protect against thyroid cancer. The thyroid gland concentrates dietary iodine and uses it to make thyroid hormones; and radioactive iodine is one of the byproducts of a nuclear explosion. Because the thyroid is extremely sensitive to radiation, uptake of large amount of radioactive iodine can result in benign nodules and thyroid cancer. The risk is greatest for younger individuals.  Administration of potassium iodide tablets immediately after a massive exposure to radioactive iodine can block its uptake and protect against thyroid cancer. Daily administration of iodide pills can also protect against chronic exposure to radioactive iodine. 

Only one way to avoid effects

The bottom line: limiting exposure to radiation is the only way to completely avoid both its acute and long-term ill effects. Even so, the radiation being released into the atmosphere from the nuclear plant in Japan is not considered a health hazard here in the U.S. This is because the average person gets much more radiation exposure from natural sources such as cosmic radiation from the sun and outer space, ground rocks and dirt, and even from some foods and water.

For more information about radiation and its effects, visit the U.S. Nuclear Regulatory Commission website. 

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