The recent earthquake in Japan triggered the destruction of nuclear power plants and nuclear leaks, which in turn caused a butterfly effect that spread to China and led to a salt shortage due to speculation about iodized salt. In fact, there is no need to worry about this at all. Because of the simple truth: iodized salt can protect against radiation, but you can’t take salt as a meal. Because too much salt is not only unbearable for people to eat, it can also cause health problems. It can cause high blood pressure and edema, and it can also aggravate heart disease and kidney disease.
The so-called iodine to prevent radiation, but only for iodine 131, a radionuclide some effect. General knowledge of physics and chemistry tells us that there are several isotopes of iodine, among which iodine 131 is one of the more dangerous radionuclides. The body absorbs iodine mainly in the thyroid gland. In radiation contaminated areas if the human thyroid gland does not absorb enough iodine it gives the opportunity for iodine 131 to enter the body, thus increasing the level of radioactive iodine in the thyroid gland. It can make human cells cancerous in the shortest possible time, especially targeting the thyroid cells. However, the half-life of radioactive iodine (I-131) is 8, 3 days. This means that after about three months, almost all of the radioactive iodine will have decayed and will be gone.
The absorption of radioactive iodine-131 by the body’s thyroid gland can be blocked by pre-taking tablets containing stable iodine isotopes. Since iodine is less likely to accumulate in the thyroid gland, it can be excreted from the body in a short time, thus reducing the radioactive hazard of iodine-131 to the human body. The dosage is based on adults taking one tablet (equivalent to 100 mg of iodine equivalent) in the first 24 hours.
However, iodine tablets need to be taken under the guidance of the relevant personnel. Taking them at random may lead to iodine overload and cause diseases such as goiter. Various drugs with low iodine content, on the other hand, do not have any effect on radiation protection. The iodine in iodized salt only makes up for the lack of iodine in food, and its low content, together with the limit of salt intake, determines that iodized salt does not play much of a preventive role. So there is no need to panic too much.
I think that if the time comes to protect people from radiation, the epidemic prevention department will distribute iodine tablets to people. It’s like giving people a flu vaccination in case of influenza A.
How to avoid nuclear radiation
Pharmaceuticals are not reliable for protection against nuclear radiation, and the most effective is lead plates.
When protection against radiation is needed, there are three important principles: time, distance and shielding.
The first two are obvious: the shorter the time you receive radiation and the farther away you are from it, the less dose you will receive.
Shielding: When you are in the hospital for an X-ray, your doctor will ask you to put some lead bags on some important parts of your body, which is the application of the principle of shielding. The thick reinforced concrete structure of the containment also effectively achieves shielding.
・Carry a radio: Be careful to carry a radio with batteries to listen to specific instructions at all times. Close and lock the doors and windows.
・Do not get wet and wear hats and boots: Wearing hats, bandanas, glasses, raincoats, gloves and boots will help reduce radioactive contamination on the body surface.
・Close windows and vents: If you are asked to evacuate, take care to keep windows and vents closed; use recirculated air. If you are advised to stay indoors: Turn off air conditioners, ventilation fans, boilers and other air intakes.
・Enter the basement: If possible, enter the basement or other underground area.
・Take a thorough bath and change your clothes: If you estimate that you have been exposed to nuclear radiation: Change your clothes and shoes. Place exposed clothing in a plastic bag. Seal the plastic bag and put it in an isolated place. Take a thorough bath.
・Seal food: Place food in an airtight container or in the refrigerator. Food that has not been sealed beforehand should be washed before putting it in a container.
・Don’t use the telephone: Don’t use the telephone if it is not necessary.
・Shade with lead plates, etc.: Pay attention to shielding and use lead plates, steel plates or walls to block or reduce the intensity of exposure.
・Tightly guard your five senses: When entering an area where the air is heavily contaminated with radioactive substances, tightly guard your five senses, such as covering your mouth and nose with a handkerchief, towel, fabric, etc.
Four major killers of nuclear leaks
In a nuclear leak, there are four radioactive isotopes that are more dangerous to humans: iodine-131, cesium-137, strontium-90, and plutonium-239.
Iodine-131: Among these four reflective isotopes, iodine-131 is the most dangerous. This is because it can make human cells cancerous in the shortest possible time, especially targeting thyroid cells. However, the half-life of radioactive iodine (I-131) is 8.3 days. This means that after about three months, almost all of the radioactive iodine will have decayed and be gone.
Strontium and Cesium: Strontium and Cesium are second only to iodine in terms of danger. These two isotopes can sneak inside the body and hide in people’s bones for many years. Leukemia is caused by strontium. Cesium causes liver cancer and kidney cancer, among others. Cesium 137 has a half-life of about 30 years. Depending on the total amount of radioactive material in the deposited ash, some decontamination and necessary radiation reduction measures (e.g. agriculture, forestry, etc.) may be required.
Plutonium-239: The biggest headache is plutonium-239, which is the main component of fuel rods. This radioactive element is very toxic. It can be transmitted by breathing and thus can cause lung cancer.
What is nuclear radiation?
In simple terms, a type of energy emitted by radioactive materials in the form of waves or particles is called nuclear radiation.
Nuclear radiation is radiation that comes from the nucleus of an atom. There are three main types of nuclear radiation that affect humans, namely alpha, beta, and gamma rays.
Alpha radiation is a stream of particles consisting of the nuclei of helium atoms. It is massive and charged, but has a weak ability to penetrate matter and has a short range, and can be blocked by an ordinary piece of paper. However, if it enters the human body, it can cause harmful internal radiation, so it is important to protect against alpha emitters in particular.
Beta ray is composed of high-speed electrons. Compared with alpha rays it has greater penetrating power and can penetrate the cuticle of the skin and cause damage to living tissue, but it is easily shielded by materials such as plexiglass, plastic or aluminum plates. Its internal exposure is also less harmful than alpha rays.
γ-rays are similar to X-rays in that they are also composed of invisible photons. It has the strongest penetrating power and can penetrate a concrete wall more than one meter thick. A γ-ray with an energy of 1 MeV is enough to penetrate the human body. Therefore, the protection of external exposure to γ-ray protection is the most important. However, because γ rays are uncharged photons, they cannot cause ionization directly, so they are less harmful than α and β rays to human body.
Nuclear radiation can cause those injuries
Radioactive material can be inhaled through breathing, skin wounds and digestive tract absorption into the body, causing internal radiation, y radiation can penetrate a certain distance by the body to absorb, so that the personnel by external radiation injury. Symptoms of internal and external radiation exposure to form radiation sickness include: fatigue, dizziness, insomnia, skin redness, ulcers, bleeding, hair loss, leukemia, vomiting, diarrhea, etc.. Sometimes it also increases the incidence of cancer, deformation, hereditary lesions, affecting the health of several generations. Generally speaking, the more radiation energy the body receives, the more serious its radiation disease symptoms, the greater the risk of cancer and teratogenic.
The following are the consequences of the amount of radiation (in millirems) suffered.
450000～800000： Within 30 days will enter a dying state;
200000 to 450,000: hair loss, severe blood lesions, some people die within 2 to 6 weeks;
60,000-100,000: various radiation diseases;
10,000: the probability of developing cancer is 1/130;
5000: Annual exposure to nuclear radiation at work;
700: Amount of nuclear radiation in brain scans;
60: The amount of radiation in the human body;
10: Radiation exposure from air travel;
8: Annual radiation exposure from building materials;
1: Radiation exposure from an X-ray of the leg or arm.