What do we know about radiation exposure after Fukushima and what can we do to prevent it?

Since the Fukushima accident, radiation exposure, its effects, and preventive measures have become important issues. This course will cover the concept of radiation, the effects of radiation exposure, ways to reduce radiation exposure, especially for medical purposes and in unexpected situations, the role of the government, and suggest ways to understand the dangers of radiation and prepare appropriately.

 

Since the Fukushima disaster, “radiation exposure,” its effects, and preventive measures have become a hot topic in Japan and Korea. So, what is radiation?
The nucleus of an atom is basically composed of protons and neutrons. When protons and neutrons combine to form an atomic nucleus, the ratio of protons and neutrons creates either a stable nucleus or an unstable nucleus. When an unstable nucleus turns into a stable nucleus, it emits alpha rays, electrons, gamma rays, X-rays, neutrons, and so on, and these substances are called radiation. These radiations are much more dangerous than other electromagnetic waves because they have more energy.
We are exposed to a variety of natural and man-made radiation in our daily lives. The unit of radiation dose is the millisievert (mSv), which is the amount of radiation an organism absorbs per unit gram. In the case of natural radiation, the average radiation dose received by Korea’s citizens in a year is about 3 mSv, and the Nuclear Safety and Regulation Act limits the radiation dose received by the general public from artificial radiation, excluding natural radiation, to 1 mSv per year. The radiation dose that causes abnormal changes in the body’s cells is known to be around 100 mSv, and Korea’s radiation dose limit is about 1% of this value, so it can be said that it applies very strict standards. However, therapeutic radiation used in hospitals is known to be around 0.1 mSv for a single chest X-ray and 8~10 mSv for a single CT scan, and radiation used for beneficial purposes such as diagnosis or treatment is not subject to the above dose limit.
In the case of radiation used in hospitals, it plays an essential role in saving lives and keeping patients healthy. For example, radiation therapy used to diagnose or treat cancer is an important means of effectively destroying tumor cells. These treatments provide patients with a quick and accurate diagnosis, which is very helpful in planning the appropriate treatment. Therefore, radiation used for medical purposes is considered an indispensable tool to keep patients healthy.
Some argue that therapeutic radiation is actually harmful to health. However, it is currently considered reasonable that therapeutic radiation is not included in the dose limit because the benefits outweigh the risks, and measures are in place to ensure that patients are informed of their exposure during hospital examinations and that exposure is recorded in medical records.
Radiation exposure, which refers to exposure to radiation, is divided into acute and chronic exposure depending on the time of exposure. Acute exposure, which is a sudden exposure to a large amount of radiation temporarily, causes acute effects on the human body. There are no symptoms below 250 mSv, but above 500 mSv, the number of white blood cells temporarily decreases, and physical abnormalities such as vomiting, hair loss, and skin changes occur as the dose increases. The body’s response to radiation is also affected by the type of cell and its regeneration rate, and nerves and muscles, which are relatively slow to regenerate compared to tissues and organs that divide rapidly, are less sensitive to radiation and are less affected. However, there are some individual differences, so these are rough guidelines to give you an idea of the level of damage. In general, acute radiation exposure occurs during an accident or radiation therapy, while chronic radiation exposure occurs over a long period of time after an accident.
In the event of a major radiation incident, such as the Fukushima accident, we need to take a number of steps to minimize the health risks from radiation exposure. First of all, in the case of therapeutic radiation intended for treatment, it is best to avoid repeating CT scans of the same area within a month or examining multiple areas at once. For medical exams, it’s best to avoid having another CT scan immediately after a PET-CT and ask your doctor if you can have an ultrasound or MRI instead, both of which do not involve radiation. It’s also important to learn how to complete the exam in one sitting.
In contrast to these medical exposures, an accidental exposure like the one at Fukushima would be more of a chronic exposure than an acute one, so the treatment would be different. First of all, since the skin does not absorb radioactive materials, you can wear light clothing, but you should shower frequently. You should be especially careful on days with strong winds, which can blow radioactive materials off the ground, and dry your laundry inside the house, while on days with light winds, you can open windows and ventilate the area. When you go outside, wear a mask if possible, and avoid puddles or wear boots as they contain more radioactive material. It’s also a good idea to brush off your clothes outside, as dry cleaning doesn’t remove radioactive materials, and if it’s raining, wipe your shoes with a damp tissue before you go inside.
Cleaning is also very important, and mopping once a week can reduce the radiation dose by as much as 0.04%, so frequent mopping is recommended, and mopping the walls and furniture in the room beforehand and circulating the air in the room with air conditioning can be more effective.
When it comes to food, it’s best to choose products that are far away from the accident site to minimize the exposure to your body, especially milk, as many children who consumed milk produced far away from the Chernobyl accident developed thyroid cancer. It’s also good to eat foods that are high in iodine, such as nori, wakame, kelp, and egg yolks, but don’t consume too much.
Water supplied by municipal utilities is not affected, so you shouldn’t have to worry too much about using the tap, showering, swimming pools, etc.
On a personal level, these measures can be taken to minimize exposure. However, the most important and fundamental thing is the government’s response. In the event of such an outbreak, the government should immediately equip all food production centers with radiation detectors and implement producer guarantees. In particular, lower radiation limits should be set for staple foods such as rice to reduce internal exposure, and land should be assessed for contamination and decontaminated to prevent contaminated crops from continuing to be produced. In addition, governments need to be more proactive in their efforts to protect the “vulnerable,” such as infants, children, and pregnant women. In Japan, for example, young parents took it upon themselves to protect their children in the immediate aftermath of the Fukushima disaster because the government failed to distribute iodized water despite the availability of iodine.
Governments also have an important role to play in providing the public with accurate information about radiation exposure and reducing fear of radiation. Misinformation or fear of radiation can lead to unnecessary confusion and fear, so it is important for governments to provide transparent and reliable information and to increase understanding of radiation exposure through education programs.
So far, we’ve discussed ways to reduce the harm caused by radiation exposure. Of course, it’s best to avoid accidents, but there are always surprises, and there are situations where it’s unavoidable, so we’d like to end this article with a reminder that it’s safer to hold the handle of the double-edged sword of radiation if you’ve knocked on every stone bridge before crossing it.