Exploring the Nuclear Accidents of Japan: A Tremor, a Tsunami, and the Dark Cloud It Left Behind
We all have heard the saying that "History repeats itself". But how many of us actually witness the repeat of a major catastrophe in our limited life spans? The residents of the country aptly named "The Land of the Rising Sun" can easily vouch for this as they witnessed their homeland get hit by balls of radiation twice in past 50 years: once during the 1945 atomic bombing attacks on Hiroshima and Nagasaki in World War II, and the other more recent one caused by the destructive earthquake-fed tsunami that hit the coastlines on March 2011.
The Great East Japan Earthquake, Tsunami, and Explosion
The nightmare for Japan's residents began when the 9.0 magnitude undersea megathrust earthquake off the coast of Miyagi Prefecture took place on March 11, 2011. The Tohuku earthquake unleashed a quake-fed tsunami, whose waves rose nearly 37.9 meters, killed hundreds of people, and damaged nuclear plant reactors (Sakai).
Following safety protocols, a total of 11 nuclear reactors from 4 Japanese plants, including Fukushima Daiichi and Fukushima Daini, were automatically shut down (Australian Federal Police). However, even when reactors are shut down, heat continues to be released. In each reactor's core, fissioning, or splitting, of uranium and plutonium atoms causes smaller, unstable atoms to be released; as a result of their instability, these atoms release the radioactive gamma, beta, and alpha particles along with large quantities of thermal energy, or heat. In order to cool down this heat, the reactors need to undergo a cooling process. Usually emergency diesel generators pump cold water and circulates it to cool down the reactor. However, these pumps and the backup systems failed at the two Fukushima plants, causing large amounts of heat to build up (Evans and Rayner; Lochbaum). As a result, nuclear meltdowns, or damage of the nuclear reactor core, took place, causing release of radioactive material into the environment (Wood). The plant employees are supplying cold sea water into the reactors in an attempt to cool them. The nuclear plants' emergency vents, which are designed to relieve pressure from the plants, also failed. This led to leakage of hydrogen, which reacted with the cold water and produced three successively large explosions at the Fukushima Daiichi plant (MyPressOffice; Sanger and Wald). The International Atomic Energy Agency is concerned that the third explosion may have damaged the reactor's primary containment vessels that are needed to prevent radioactive leakage (Evans and Rayner).
Exceedingly high radiation levels have been recorded near Fukushima Daiichi, and Japan's Chief Cabinet Secretary Yukio Edano gravely admitted that, "Now we are talking about levels that can damage human health." Edano has asked residents living 18 miles or less from the site of the accidents, making up more than 140,000 people, to stay in their homes and lock their windows to block out the radiation (Chusteka; Evans and Rayner). Other precautions include a ban on consumption of food and drinks coming from the site of exposure and a distribution of potassium iodide tablets to residents to inhibit thyroidal intake of radioactive iodine released by the reactors, as shown in Figure 3 (Chustecka).
Many days later on April 7th, 2011, in response to measurements of continued radioactive leakage from the reactors, Europe's Energy Commissioner Gunther Oettinger, addressed the European Parliament citing that even though the Fukushima accident was not the world's worst nuclear disaster ever, it was the most complicated. "It was an apocalypse" (Evans and Rayner).
Courtesy of Environmental Protection Agency
Concerns Regarding Radiation Levels
There are two types of radiation, ionizing and non-ionizing radiation (see Figure 1), and humans are exposed to minute levels of both everywhere – from food, solar energy, cosmic radiation, and even medical diagnostic machines such as X-Rays, CT scans and MRIs. Non-ionizing radiation comes from microwaves, radio waves and visible light. This type has enough energy to move around the atoms within a molecule, but not alter them chemically. On the other hand, ionizing radiation is found in all the remaining sources including food, nuclear power plants, radioactive waste, and medical imaging machines such as PET scans, X-rays, MRIs and CT scans.
In the United States, radiation dose is measured in units of rem, or roentgen equivalent in man. Elsewhere, it is measured in the metric units of sieverts (Sv), with 1 Sv equaling 100 rem. In the United State, the amount of background radiation to which people are exposed tallies to about 0.3 rem per year (Health Physics Society).
According to Edano, the radiation level near the site of the nuclear accidents has reached 400 millisieverts (mSv) per hour, or 40 rem per hour, which is 20 times the annual exposure for most nuclear plant workers (2-3 mSv per year), making energy agencies and Japanese officials wary (Health News).
Effects of Radiation on Health
When the body is exposed to radiation, at a cellular level, the radiation particles can directly or indirectly cause ionization of DNA. Indirect ionization occurs when the radiation particles ionize water, thereby producing free radicals. Direct ionization occurs when DNA becomes ionized, losing electrons and creating free radicals, especially the hydroxyl radical •OH. These free radicals are then free to damage DNA through oxidation, as shown in Figure 2 (Artemis Medicare Services Pvt Ltd; Environmental Health and Safety).
When DNA damage takes place, cells that proliferate at very low or insignificant rates, such as muscle and nerve cells, have time to repair their DNA before DNA replication and cell division takes place. However, cells that grow at fast rates do not have sufficient time to repair the DNA before replication takes place. As a result, cells that are rapidly proliferating or differentiating are the most sensitive to radiation; these include gastrointestinal cells, blood cells (white blood cells, red blood cells, and platelets) forming in the bone marrow, reproductive system cells, skin cells, and hair follicles (College of Veterinary Medicine; Environmental Health and Safety). Several highly common radiation-caused side effects can be traced to those particular sites of damage, such as anemia (blood cell damage), loss of appetite and taste (gastrointestinal cell damage), hair loss (hair follicle damage), flaky or burnt skin (skin cell damage), and fatigue (probably due to blood cell damage) (Environmental Health and Safety; National Cancer Institute).
By ionizing DNA, radiation has the ability to damage DNA and cause cells to become cancerous (American Cancer Society). Exposure to ionizing radiation doses above 150 rem can cause Acute Radiation Syndrome (ARS). Symptoms of ARS include nausea, vomiting, diarrhea, hair loss, itching, and swelling. These symptoms can begin within minutes to hours to days after exposure and last for weeks or even years (Infoplease).
Below is a non-exhaustive chart of the effects of different doses of radiation on the body.
Effects of Radiation from Fukushima Nuclear Accidents
There are few plant workers who have reported symptoms of nausea and vomiting and were treated at a hospital for radiation exposure. However, physicians are at present not concerned about the effects of radiation from the nuclear accidents on most Japanese residents. They believe that the radiation levels being recorded are not high enough to cause any serious symptoms (Grady).
Some are concerned that residents near the Fukushima plants are at risk of developing ARS in the near future. However, most health officials are optimistic that this risk is low. The nuclear accident at the Fukushima plants is the first serious nuclear accident since the 1986 meltdown of the Chernobyl plant in Ukraine. Most of the residents near that meltdown suffered from ARS. However, the Chernobyl meltdown involved an explosion of the reactor core, exposing nearby residents to higher levels of radiation than the Fukushima nuclear accident. Furthermore, Ukrainian officials evacuated the area near the nuclear accident 24 hours after the meltdown while Japanese officials evacuated residents near Fukushima within a few hours after the accident, shortening the exposure period of the residents (Infoplease).
According to James Cox, M.D., a radiation oncologist at MD Anderson Cancer Center, in the long run, nuclear plant workers will have a statistically significantly higher risk of cancer now than before the accident. However, he claims that this risk is not as high as most people probably think (MD Anderson Cancer Center).
The radiation exposure from the Japanese nuclear accident follows what Dr. Cox has termed a "dose-related phenomenon." In other words, radiation levels are higher near the site of the accident and lower away from the site. While people near the site of the accident may have a high risk of developing cancer in the long run, people living in the United States, Korea, China, and even Tokyo are not at risk of any negative impacts on their health from the radiation (MD Anderson Cancer Center).
Courtesy of Alexander Higgins.
According to David Brenner, M.D., director of the Center for Radiological Research at Columbia University, and Dr. Cox, radioactive particles from the reactor were probably carried by winds, landed on the ground, and reacted with the concrete, crops and other materials. These particles, including Iodine-131 and Cesium-137, were absorbed by crops near the site of the plant. People could consume these particles by eating the crops, eating meat from animals who consumed those crops, and by drinking milk from such animals (Grady; MD Anderson Cancer Center). In fact, many children near the Chernobyl meltdown developed thyroid cancer by drinking cattle milk produced near the site of the meltdown (MD Anderson Cancer Center). To avert this tragedy, Japanese officials have banned consumption of food and drinks coming from the site of exposure (Chustecka).
Precautionary Measures and Future Direction
In addition to the ban on food and drink near the Fukushima plants, officials are distributing potassium iodide tablets to residents. Generally, the body uses stable, nonradioactive iodine to make thyroidal hormones, which regulate hormone production and function throughout the body. The thyroid can only absorb a certain amount of iodine before it filters out the excessive iodine away. Absorbing radioactive iodine-131, such as from failing power plants, however, can be a problem; but a problem with an easy solution. While the effects of stable iodine and radioactive iodine differ, the body cannot distinguish between the two forms before absorption. Therefore, by taking stable, nonradioactive potassium iodine pills, physicians assure that people's thyroid glands will have a higher supply of normal iodine, causing the glands to have a great probability of absorbing only normal iodine and to filter all the radioactive iodine out of the body (Wehrwein).
Environmental specialists are optimistic that the radiation particles near Japan have not spread far from Fukushima and will dissipate and return to normal levels soon. Didier Champion, the environment director of IRSN, agrees with Dr. Cox that while radiation is likely to be concentrated within 10 to 20 kilometers from the Fukushima plants, there is probably less contamination farther away from the site (Kwek). Furthermore, since Iodine-131 has half-life of 8 days, these radioactive iodine particles will disappear within a few months or weeks. Even though other particles may have longer half-lives, such as caesium-137 with a half-life of 30 years, these particles will gradually dissipate in the air and become diluted (MD Anderson).
Till the year is passed, Japan continues to rise from its windfall and take precautionary measures in health. They issue iodine tablets to local residents in Fukushima region, import food from other countries, and offer free health examinations at evacuation sites to ensure both that the exposure levels are within range in the exposed population and that there are no initial signs of cancer (U.S. Army Asian Studies Detachment).
Problems could arise for the local Japanese population around the Fukushima region if they continue to drink the water, milk and vegetables produced in that contaminated area. While the leak continues to emit radiation several months after the initial blasts, the radiation levels should still leave most of the Japanese population safe and at low risk of developing cancer in the future. The Radiation Effects Research Foundation plans to follow up with people near the site of the nuclear accidents in the long run to determine the effects of the radiation exposure on their health and cancer risk (MD Anderson Cancer Center). To people throughout the world, this series of tragic events, from an earthquake to a tsunami to radiation-releasing nuclear accidents, serves as a sobering reminder of the dangers that may await us no matter how prepared we think we are. Nevertheless, just as Japanese officials averted the mistakes made in Chernobyl, learning from the past and conducting follow-ups with the people near Fukushima Daiichi can allow us to create better measures and solutions to combat the potential health effects of such disasters in the future.