How does iodine protect against radioactivity from a nuclear explosion?

Nothing more destructive and deadly can be imagined than an accident at a nuclear power plant or the explosion of a nuclear weapon. We know the consequences of Hiroshima, Nagasaki and Chernobyl. And in the world there are more than 13,000 nuclear projectiles and 400 nuclear reactors. We can only protect ourselves by trying to apply common sense and… with a little iodine. Why iodine?

What is iodine?

Iodine is an essential element for life. It’s a necessary nutrient for the synthesis of the growth-regulating thyroid hormones, thyroxine and triiodothyronine (T4 and T3 respectively).

An iodine deficiency causes decreased production of T3 and T4 and a concomitant enlargement of thyroid tissue in an attempt to obtain more iodine, resulting in the condition known as simple goiter.

The body cannot produce iodine on its own, so we must get it from food. The daily requirement is about 200 mcg. The iodine that is not used to produce hormones serves to replenish the reserves that accumulate in the thyroid tissue.

Iodine protects from radioactive iodine

Nuclear explosions release radioactive iodine (iodine-131), which causes a type of thyroid cancer, which spreads to the lymph nodes, and other diseases. As a consequence of the Chernobyl accident, cases of thyroid cancer multiplied by one hundred in the area affected by radioactivity.

When we are exposed to radioactive iodine, the body absorbs it and over time the cells of the thyroid gland are damaged. Children and young people are especially vulnerable.

Radioactive iodine blocking

If a high dose of iodine is taken before the radioactive iodine cloud arrives, the thyroid gland will already be saturated with non-radioactive iodine and will not absorb the radioactive. This form of prevention with non-radioactive iodine is called iodine blockade.

There are iodine blocking tablets that contain 65 mg of potassium iodide (with 50 mg of iodine). The required doses are as follows:

Children under 1 month: 16.25 mg potassium iodide (a quarter tablet) Children from 1 month to 3 years: 32.5 mg potassium iodide (half a tablet) Children between 3 and 12 years: 65 mg potassium iodide (one whole tablet) People between 12 and 45 years old (including pregnant and lactating women): 130 mg potassium iodide (two tablets).

People over the age of 45 do not should take iodine tablets because the disadvantages would outweigh the benefits (such as metabolic disorders or side effects on the thyroid gland).

Also, thyroid cancer does not develop as often in older people and takes several decades to develop.

Iodine tablets can be swallowed whole or dissolved in water or juice. The liquid should be drunk immediately. The pure iodine content in potassium iodide is around 77%, which means that the adult dose is 100 mg of iodine.

Iodine supplements contain very low doses (150-250 mcg), 500 times less than iodine blocking tablets.

The right time to take iodine

In the worst case, the emergency services will distribute the iodine-blocking tablets to people living within a radius of 100 km of an incident or who are about to fall victim to a cloud of radioactive iodine.

The ideal is take the iodine tablets between 24 and 48 hours before the arrival of the cloud of radioactive iodine.

If necessary, iodine tablets they can also be taken after contact with radioactive iodine, however the protective effect is less (after 2 hours a maximum of 80% protection, after 8 hours only a maximum of 40% protection)

If the high dose of iodine is taken no more than 48 hours before contact with radioactive iodine-131, the block works very well and the absorption of radioactive iodine by the thyroid gland can be almost completely prevented, regardless of whether the person in question was previously well supplied with iodine or had an iodine deficiency.

If the iodine tablets are taken too soon (96 hours before the radioactive iodine arrives), they will have little or no protective effect.

A good supply of iodine is important

You don’t have to wait for a nuclear disaster to worry about getting enough iodine. The lower a person’s natural iodine level prior to exposure to radioactive iodine, the greater their risk of developing thyroid disease from radioactive iodine. And the body needs iodine to maintain health. Therefore, iodine deficiency should always be avoided.

In the omnivorous diet, fish is the main source of iodine. In the vegetana, it is iodized salt and seaweed (They are very rich in iodine, but they must be taken sparingly because excess is also dangerous).

But there are other radioactive elements

Taking iodine only protects the thyroid gland and only prevents the harmful effects of radioactive iodine. But in a nuclear disaster other radioactive particles are emitted, such as xenon-133, tellurium-132, cesium-134 and -137, strontium and plutonium.

Not all of these particles spread equally, so not all people are affected equally. The first three and iodine can be carried by the wind for thousands of kilometers.

Radioactive strontium and plutonium are not volatile and do not spread beyond a 100 kilometer radius from the accident or explosion site, but they have an extremely long half-life.

Plutonium, for example, has a half-life of several thousand years, meaning that only half of the plutonium in the environment has decayed in this period. Plutonium-240 has a half-life of 6,500 years and plutonium-239 has a half-life of 24,100 years. Therefore, Radioactive plutonium activity in the former Chernobyl reactor is still as high today as it was on the day of the accident, now more than 35 years ago.

The half-life of radioactive cesium and strontium is 30 years. Iodine-131 and xenon-133 have a very short half-life (iodine 9 days), so these two almost completely break down after just three months.

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