What to do when radioactive contamination?

Repeated explosions of nuclear reactors happened in Japan. The level of radiation in some areas is higher than normal. Not only are Japanese people panicked, but residents of neighboring countries are also worried.

BBC media firm led analysis of experts assessing nuclear risks and how to respond in this crisis:

Has radioactive material leaked into the air?

Already. Japanese officials at Fukushima, where a nuclear power plant has the same name, said 190 people were exposed to radiation. USS Ronald Reagan also detected a small amount of radioactivity at a distance of 169 km from the factory mentioned above. Radiation has even spread to Tokyo, which is about 250 km from the factory. Those who lived within 20 km of the factory were ordered to evacuate, while at a radius of 30 they were advised to stay indoors.

Fukushima nuclear power plant fumes after an explosion - Photo: Reuters

What is the immediate effect of radiation on human health?

Exposure to a small amount of radiation - level 1 gray - may cause discomfort to people with a series of symptoms such as nausea, vomiting only within a few hours after exposure, then may be diarrhea , headache and high fever.

After this symptom can be a perfectly normal few weeks, but may be more serious new symptoms later.

If exposed to high levels of radiation, all of the above symptoms may appear immediately in addition to damage to a range of internal organs, which can lead to death. 4-gray radiation exposure can kill half of healthy people.

Usually, cancer patients undergo radiotherapy through multiple radiation doses ranging from 1 to 4 gray. However, this process is strictly controlled, targeting only a small area of ​​the body - where cancer cells are concentrated.

What is the long-term harm?

Radioactive substances and cancer

Most experts agree that only a very small amount of ionizing radioactivity - as small as 100 millisievert, can increase the risk of cancer, but increases very low.

In general, the risk of cancer increases if the body is exposed to more and more radiation. Exposure to 1 sievert (1 gray) radioactive substance increases the risk of cancer leading to death throughout a lifetime by about 5%. Thyroid and bone marrow are particularly sensitive places for ionizing radiation. Leukemia - a type of bone marrow cancer - is a common cancer caused by radioactive substances. This disease may appear only a few years after exposure to radiation. Other types of cancer usually appear only after at least 10 years, including lung, skin, thyroid, breast and stomach cancer.

Cancer is the biggest danger in the long term. Normally, when the cells in the body have 'expired', they will commit suicide. Cancer causes cells to lose this ability, meaning they become immortal, continuing to divide in ways that the body can't control.

In addition, our bodies operate in a way that helps cells not get cancer and automatically replace sick cells. However, this mechanism is broken by exposure to radiation, making people more susceptible to cancer.

The inability to overcome the radiation-induced damage can also lead to mutations in the genetic mechanism, which may have consequences for future generations, including cerebral palsy and eyes. incomplete, mental retardation .

Is the risk in children higher than usual?

Can be right. The baby's body grows rapidly, more cells divide, so the damage is often greater.

After the Chernobyl nuclear disaster in Ukraine in 1986, the World Health Organization found a significant increase in the proportion of children with thyroid cancer in the area near the explosion.

How much radiation is harmful to health?

Radioactive material can cause significant damage to the chemicals in the body's internal organs , breaking chemical bonds between atoms and molecules, which make up tissues.

Check the level of contamination for people in the area near the Fukushima plant - Photo: AFP

The body immediately reacts by trying to overcome these damages, but in many cases, the level of damage is so great that it cannot be overcome. There are also cases where the body's natural remedy mechanism malfunctions.

The severity of the problem depends on how much radiation you have been exposed and for how long.

The level of radiation damage to health:

- 2mSv / year (millisievert / year)
This is the average level of radiation exposure in everyone (1.5 mSv in Australia and 3 mSv in North America).

- 9 mSv / year
Exposure of crew on New York - Tokyo flights

- 20 mSv / year
The current average limit for employees in the nuclear industry

- 50 mSv / year
The previous average limit for nuclear industry employees. This is also in nature at many locations in Iran, India and Europe.

- 100 mSv / year
The lowest level identified can increase the risk of cancer.

- 350 mSv / lifetime
Criteria for relocation for people after the Chernobyl disaster.

- 1,000 mSv in a single dose
May cause temporary harm, such as nausea, decreased white blood cell count but not fatal.

- 5,000 mSv for 1 dose
Can kill ½ of contacts within 1 month.

(According to the World Nuclear Association)

What are the risks of radiation leaks at Japan's Fukushima nuclear power plant?

The Japanese government announced that it could measure radiation up to 400 millisiever / hour at the factory. A sievert is equivalent to a gray.

Professor Richard Wakeford of the University of Manchester (UK), which specializes in radiation exposure, said the above exposure levels are not enough to cause illness. The problem only arises in double the content. However, a level of 400 millisiever per hour can also trigger a process to degrade the production of blood cells in the bone marrow and increase the risk of cancer leading to death during a lifetime of 2 people. -4%. Usually, this risk in Japan is between 20-25%.

But only those working at the emergency parts of the Fukushima plant could have been exposed to the radiation levels listed above. The time when they were exposed to 400 millisiever / hour was also thought to be short, causing the risk to decrease.

The level of radiation exposure to most Japanese people, including those living near the plant, is low.

This baby is being measured for radiation levels - Photo: AFP

What to do after radioactive contamination?

The first thing to do is to remove all clothes and shoes to minimize the risk of further contamination, then gently wash with soap and water.

There are a number of drugs that promote leukocytosis to counteract the harms caused to the bone marrow as well as to minimize the risk of further infection by the immune system. There are also other drugs that can help reduce the damage caused by radioactive substances to internal organs.

What does the Japanese government do to minimize health risks for people?

According to Wakeford, if the government and people respond promptly, most people will not suffer any significant damage. The top priority is to evacuate people in the area around the factory and ensure that they do not eat contaminated food. The biggest danger is infection of radioactive iodine, which can lead to thyroid cancer. To deal with this, it is necessary for everyone, especially children, to use stable iodine tablets, which can help the body prevent radioactive iodine infection.