Radiation and Health: The Aftershocks of Japan's Nuclear Disaster

Written in collaboration with Sophie Turrell, Praveen Pendyala, Katherine Warren, and
Laura Macherelli

On March 11, 2011, a magnitude 9.0 earthquake struck Japan, causing a devastating tsunami that tore through the coastal regions and leveled the villages in its path. The earthquake also severely damaged nuclear reactors at the Fukushima Daiichi Power Plant, sparking explosions and the release of radioactive material. This event is the world's worst nuclear accident in 25 years, rated by the International Atomic Energy Agency to be a level 7 out of 7 in severity -- on par with the Chernobyl accident in 1986.

Recent reports suggest that leaks from the reactor's core may be extremely dangerous, not only threatening workers there but also contaminating the facility and surrounding community on the longer term. Radioactive material leaking into the ocean (7.5 million times the legal amount of iodine-131 and 1.1 million times for radioactive cesium near the facility) has sparked concerns about the effects on fish and other sea life in the vicinity as well as the spreading of radiation to distant shores. As Japanese engineers, scientists, and firefighters work to control the continuing crisis at the vulnerable Fukushima plant -- efforts that are hindered by strong aftershock earthquakes -- fears about the scope of this nuclear disaster and the radiation's health effects continue to spread. While experts underscore that there are no health risks to the United States, radiation continues to enter the environment in the vicinity and has spread to other regions as well.

Radioactive elements have been escaping from the Fukushima plant in the form of gas emissions as well as contaminants in the seawater that emergency workers have been using to cool the reactor's overheating fuel rods. These elements can travel beyond the vicinity of the plant in a several ways.

First, the particles released as gases into the atmosphere can be blown by winds and other weather patterns to far-off locations. This is the "radioactive plume" that is responsible for the small amounts of radioactive iodine-131 detected in scientific stations in air or rainwater samples as far away as California, Colorado, Washington State, Massachusetts, Florida, Illinois, and North and South Carolina. Trace amounts of iodine that have been found in milk in San Luis Obispo, California and in Washington State, for example, are increasing the fear of widespread radiation contamination, but the amounts that have been detected so far are 5,000 times lower than the amount that would trigger FDA restrictions. For people living in America, these miniscule levels of radiation pose no health risk or threat to water and food supplies at this time, and there is no need to take any action right now. However, monitoring of radiation levels must continue. Samples are being collected in more than 100 sites in the United States that are part of the Environmental Protection Agency's Radiation Network Monitoring System.

In Japan, the particles in the air near the plant are more concentrated. They can settle to the ground or enter clouds and be returned to earth in the rain, which can coat plants that animals eat or that are produced as food for humans. Radioactive particles from the nuclear facility can also be absorbed by the soil, contaminating groundwater that feeds plant life, agriculture, and drinking water supplies, as well as be washed out to the ocean, where it may affect sea life. Radioactive groundwater underneath the reactor has been measured at 10,000 times the government health standard. In addition, high levels of cesium-137 have been found in one village 25 miles away from the power plant (outside of the initial 20 kilometer evacuation zone). The Japanese authorities are extending the evacuation zone to 30 kilometers from the plant in some areas. The U.S. government has advised citizens who are living in a 50-mile radius from the plant to evacuate or shelter in place.

These events have not just affected the area within the evacuation zone but have contaminated some of the water and food supply for people living in other areas of Japan, including Tokyo. The city first reported a spike of radioactive iodine in its water supply on March 23, 2011 at levels below the limit for adults but above the threshold of safety for infants; since then, iodine levels in Tokyo's water have declined below both thresholds. Above-limit levels of radioactive iodine and cesium have also been found in milk and vegetables in seven prefectures in Japan. These amounts, however, may not have significant health effects; a year's consumption of these foods would give a dose of radiation equivalent to or smaller than a CT scan.

Nevertheless, several nations have begun testing or suspending imports of dairy, fruits and vegetables, dry tea, artificial flavoring compounds, seafood, and meat from the areas at risk of radiation contamination in Japan, including Australia, South Korea, Thailand, and the U.S. (which has banned imports of dairy products and fruit and vegetables from Fukushima, Tochigi, Gunma and Ibaraki).

Furthermore, high levels of radiation leaking into the seawater around the plant have sparked concern about fish and other sea life for consumption. Low levels of radiation have been found in fish caught in waters near the plant. But because Japan is not a major food exporter -- for example, food imports from Japan make up less than 4 percent of all food imported to the U.S. -- significant amounts of radiation are not likely to enter the U.S. food supply chain. However, more evidence must be gathered to determine the effects of radiation on Japan's seafood.

What is Radiation and How Much of it is Harmful?

Radiation is energy that is transmitted in the form of waves or particles. Ionizing radiation describes waves or particles that have enough energy to remove electrons from other atoms, thus creating chemically reactive ions (charged atoms) that can damage cells.

In the Fukushima plant, several types of radioactive particles have been released into the air. Chief among these are iodine-131, cesium-137, plutonium-239, and strontium-90, each of which decays at a different rate and can have various effects on the body. Iodine-131 has a half-life of 8 days - meaning that it is half as radioactive after 8 days, thus making its effects relatively short-lived. Exposure to iodine-131 can cause thyroid cancer. With half-lives of 30 and 29 years, respectively, cesium-137 and strontium-90 both stay in the environment for longer periods of time. Cesium-137 can travel through the food chain in milk or vegetables and can increase the risk of various cancers; strontium-90 is absorbed into bones and teeth and can increase the risk of leukemia or bone cancer. Plutonium-239 is toxic if inhaled.

Though the word "radiation" sounds menacing, in fact humans are exposed to naturally occurring radiation every day from the sun, cosmic rays, the soil, and other sources. People are exposed on average to 3 mSv (milli-sieverts, or one-thousandth of a sievert) per year. A sievert is the most common unit by which scientists measure the biological risk of radiation exposure, because it takes into account both the amount of radiation absorbed (measured in Gy (Gray) or rad (radiation absorbed dose)) as well as the intensity of ionization in the affected living cells.

Many commonly used medical procedures contribute to a person's average radiation exposure. To get a sense of the magnitude of 3 mSv, consider this: a typical mammogram delivers 0.13 mSv per test; a chest x-ray delivers 0.1 mSv; and a routine dental x-ray delivers 0.04 to 0.15 mSv. Individually, these are minimal exposures; however, medical professionals must take care to limit their exposures (e.g. by walking out of the room) over the course of testing many patients everyday. The health effects of radiation are cumulative, so higher doses at one time, or lower doses delivered over longer periods of time, can compromise human health.

What is considered a harmful dose of radiation? Estimates vary depending on the duration and strength of the exposure. Below is a chart produced by the Environmental Protection Agency (EPA) on health effects and exposure. Depending on the strength of the radiation, an exposed person may also experience burns or other symptoms of acute radiation syndrome (ARS). A one-time dose of 4 sieverts or more can be fatal.

To protect the health of nuclear power plant workers, the Japanese government has set 250 mSv as the maximum amount of exposure to radiation at any one time. Estimates of the radiation emitted by the Fukushima plant in Japan have ranged from a high of 1,000 mSv per hour (1 Sv per hour) inside the plant to 400 mSv per hour, 11.9 mSv per hour, and below , with levels dropping off sharply the farther away from the plant they are measured. So far, several people working to contain the damage from the nuclear plant to bring the situation under control have been exposed to high levels of radiation, including a few who were hospitalized after stepping in puddles of water at the facility that contained highly concentrated levels of radiation. Several people are currently hospitalized.

The Health Effects of Radiation Exposure

A person may be exposed to elevated levels of radiation by breathing in radioactive particles, ingesting them through exposed food or drink, or coming into close bodily contact with a source of radiation.

Different types of radiation will produce different health effects, based on the half-life of the particle (how long it takes to lose half its radioactivity, a measure of how fast it degrades) and the way it interacts with the body. Iodine-131, plutonium-239, cesium-137, and strontium-90 are the four most harmful radioactive elements involved in the Japanese nuclear disaster, with half-lives of 8 days, 24,000 years, 30 years, and 29 years, respectively. With the exception of iodine-131 which has a short half life, whatever amounts of these other elements are released are likely to stay in the environment and pose a threat to human, plant, and animal life for several years to come. Cesium-137 can deposit itself in milk and vegetables, increasing the risk of several forms of cancer for those that ingest enough of significantly contaminated foods.

Exposure to high doses of radiation can lead to a broad range of acute health problems which are usually only experienced by individuals close to the source of radiation such as reactor workers. One of the possible acute effects of exposure to high levels of radiation over a small period of time is Acute Radiation Syndrome (ARS) or radiation sickness. For an exposed individual to develop ARS, the radiation must be penetrating and cover the whole body. The radiation doses that lead to ARS hover around 1 sievert -- about 300 times the average annual dose (3 millisieverts) of background radiation. ARS is associated with damage to the bone marrow, and at higher doses (>10Sv) other organs may be affected.

Symptoms of ARS include nausea, weakness, diarrhea, headaches, fever, hair loss, skin damage, diminished organ functions and possible seizures and coma. Following the Chernobyl nuclear disaster, approximately 134 plant workers and firefighters received doses of 700 to 13,400 mSv and developed ARS. Of the 134 ARS patients, 28 died. Exposure to high levels of gamma radiation in particular can contribute to a broad range of acute health effects. For example, gamma doses of 2Gy, 10Gy and 20Gy can lead to hemopoietic syndrome, gastrointestinal syndrome and central nervous system problems, respectively. Other acute health problems that can result from high exposure to radiation include premature aging, male sterility, birth defects, and possible death.

Long-term, low dose exposure to radiation can lead to the development of chronic health conditions including cancer. Chronic exposure to radiation increases cancer risk by disrupting the control process of repairing damaged tissue, permitting uncontrolled cell growth and inhibiting apoptosis. The Chernobyl nuclear disaster significantly increased rates of leukemia, thyroid cancer and bone cancer among children in the vicinity of the reactor. Fetuses especially 2-15 weeks following conception are highly susceptible to teratogenic mutations following long term, low dose exposure to radiation. These mutations can lead to smaller head or brain size, poorly formed eyes, abnormally slow growth and mental retardation.

Pregnancy and Radiation

Children and pregnant women are particularly vulnerable to radiation. Because children are developing, their bodies experience more cell division and therefore are more vulnerable to disruptions in the normal cell growth process, making them more sensitive to the effects of radiation as compared to adults. Fetuses, in even more critical stages of development, are highly sensitive as well, with results dependent on the organ systems that are developing at the time of exposure.

The consequences through direct gamma radiation, ingestion, inhalation, or absorption through the skin can be severe even if the mother does not suffer from radiation sickness. During the first two weeks of pregnancy, exposure to radiation can lead to death. Between 2 and 15 weeks, a dose that is the equivalent of about 500 chest X-rays would increase the risk of birth defects or neurological damage in the fetus. Levels below this would lead to a slightly higher risk of having cancer later in life. After the 16th week of gestation, the radiation is unlikely to produce the same cognitive or physical defects unless the radiation is a dose of the equivalent of 5000 chest X-rays or more. After 26 weeks, the fetus as sensitive to radiation as a newborn. Pregnant women who have been exposed to radiation should take potassium iodide pills when instructed by authorities because their thyroid glands accumulate radioactive iodine at a higher rate than other adults, which can then be passed on to the fetus.

Mental Health Effects

People involved in situations where radiation exposure is a threat typically experience high levels of stress and anxiety. The uncertainty of radiations' physical and environmental effects can cause fear and confusion about its impact on health as well as on the safety and quality of the food and water supply. Peoples' worries are exacerbated by the fact that radiation cannot be detected by the human senses of taste, smell, or sight. Persons displaced by radiation in their community must also cope with having to relocate, the loss of economic stability, and the possibility of long-term health problems, all of which may contribute to post-traumatic stress and depression, among other emotional consequences.

Following the nuclear disaster at Chernobyl, people reported debilitating feelings of helplessness and lack of control over their future. They suffered psychological effects including depression, substance abuse, and anxiety disorders that were painful and debilitating. In addition, some people were stigmatized, shunned by their non-exposed neighbors for fear of radiation contamination. Those people affected by nuclear accidents may carry the burden of mental health disorders for years to come.

The mental health effects of nuclear disasters can impact distant shores with people experiencing fears about the safety of their food and water supply as well as long term health effects. This is why trustworthy health information should be communicated to the public about the risks or lack of them.

Treatment for Radiation Exposure

There are several therapeutic interventions available to reduce the effects of radiation exposure. Experimental treatments are also being studied. The most common therapy is potassium iodide (KI), which can be administered shortly before or up to 24 hours after radiation exposure. By keeping iodine levels in the thyroid at a proper balance and blocking the uptake of the radioactive iodine isotope, potassium iodide is the first line of protection against thyroid cancer caused by radioactive iodine-131 inhalation. A single dose of KI protects the thyroid gland from absorbing radioactive iodine for 24 hours, but is ineffective if radioactive iodine has already entered the thyroid gland. If radioactive iodine is in the environment for more than 24 hours, local emergency management or public health officials may instruct people to take one prophylactic dose of KI every 24 hours for a few days. KI's side effects can include stomach upsets, allergic reactions, and a rare inflammation of the salivary gland. The use of KI is not recommended for everyone.
Since the nuclear disaster in Japan, there has been an increase in the purchase of seaweed, a source of natural iodine, in U.S. health food stores. However, because seaweed can also absorb radioactive iodine, scientists caution against eating large amounts of it.

For people who have been internally contaminated with radioactive cesium and nonradioactive thallium, a substance called Prussian blue absorbs cesium-137 and thallium into the intestines in order to speed removal from the body. Side effects of this treatment include stomach upsets as well as constipation . In an effort to develop new ways to prevent the toxic effects of acute radiation exposure, the US Department of Defense (DOD) is supporting research, through its Defense Advanced Research Projects Agency (DARPA), on the effectiveness of nanotechnology approaches to treating radiation exposure. , Another substance being studied is CBLB502, a medicine that suppresses cell death and damage while inducing regeneration, making it potentially useful in reducing the negative effects of cancer radiation therapy or for promoting recovery after a nuclear accident or disaster. CBLB502 has shown promising results in preventing radiation damage in animal models.

Since the nuclear disaster in Japan has not yet been resolved, the scope and impact of health effects on the population in that country and in other nations may not be known for some time.

What You Can Do: Be Prepared in Case of an Emergency

How can you protect yourself in the event of a nuclear disaster?

● Be informed by obtaining accurate and authoritative information (i.e., information from government authorities delivered by radio, TV or the Internet) and follow instructions given by government officials.

● The decision to take potassium iodide tablets should be based on information provided by national health authorities who will be in the best position to determine if there is enough evidence to warrant its use after a nuclear disaster.
- KI only protects the thyroid gland and does not provide protection from any other radiation exposure.
- Some people are allergic to iodine and should not take KI. Check with your doctor about any concerns you have about using this substance.
When people are advised to stay indoors, what does this mean?

● When a radiological or nuclear event occurs, public health authorities may instruct residents in the affected areas to stay indoors rather than to evacuate. People may be advised to take shelter at home, at work, or in specific public spaces.

● If advised to stay indoors, people should find the safest room in their house or office building that has no windows or doors. Ventilation systems, such as heating and cooling systems, should be turned off.

● Shelter provides protection from both external and internal radiation exposure, as well as from inhalation of radioactive material.

● Taking shelter is a simple and protective action that can be implemented promptly during the early phase of an incident.

For Individuals:

• Be alert to any symptoms (fatigue, nausea, loss of appetite, etc.) and get help if you think you are suffering from acute or chronic radiation exposure.

• Develop an emergency plan for your family, including having supplies at home such as food and prescription medications. Ensure that every family member knows what to do in case of an emergency.

• At home, put together a preparedness kit that would be appropriate for any emergency. The kit should include the following items at a minimum:
- A flashlight with extra batteries
- A portable radio with extra batteries
- Bottled water
- Canned and packaged food
- A hand-operated can opener
- A first-aid kit and essential prescription medications
- Personal items such as paper towels, garbage bags, and toilet paper

• During and after a release of radioactive materials, local, state and federal authorities will monitor the levels of radiation and determine what protective actions to take.

• The most appropriate action will depend on the situation. Tune to the local emergency response network or news station for information and instructions during any emergency.

• Check with your child's school, the nursing home of a family member, and your employer to see what their plans are for dealing with a radiation emergency.

• If a radiation emergency involves the release of large amounts of radioactive materials, you may be advised to "shelter in place," which means to stay in your home or office; or you may be advised to move to another location.

• If you are advised to shelter in place, you should do the following:
- Close and lock all doors and windows.
- Turn off fans, air conditioners, and forced-air heating units that bring in fresh air from the outside. Only use units that recirculate air that is already in the building.
- Close fireplace dampers.
- If possible, bring pets inside.
- Move to an inner room or basement.
- Keep your radio tuned to the emergency response network or local news to find out what else you need to do.

• If you are advised to evacuate, follow the directions that your local officials provide. Leave the area as quickly and orderly as possible. In addition -
- Take a flashlight, portable radio, batteries, first-aid kit, supply of sealed food and water, hand-operated can opener, essential medicines, extra clothes and cash and credit cards.
- Take pets only if you are using your own vehicle and going to a place you know will accept animals. Emergency vehicles and shelters usually will not accept animals.
For Businesses and Communities:

• Businesses and communities should be prepared, especially those within a 20 mile radius of nuclear power plants.

• Develop preparedness plans as you would for other public health emergencies.

• Provide current and updated health information for your employees.

• Participate in and promote public health programs in your state and community.

• Implement actions recommended by public health officials and health care providers.

For Governments:

• Strengthen both national and global public health infrastructure to respond to a nuclear disaster.

• Develop coordinated strategies for communication and response that cross sectors, agencies, and countries.

• Ensure that potassium iodide is part of the national stockpile of medical supplies and that it is provided to communities within a twenty mile radius of nuclear power plants in case of a nuclear accident or disaster.

Stay Informed---Helpful Internet Resources on Radiation and Health Include:

• World Health Organization (WHO) FAQs and Report on the Current Situation in Japan

• CDC resources on radiation emergencies

• Nuclear Regulatory Commission Recommendations


• U.S. Environmental Protection Agency's Office of Emergency Management

*Rear Admiral Susan Blumenthal, M.D., M.P.A. (ret.) is the Public Health Editor of the Huffington Post. She is also the Director of the Health and Medicine Program at the Center for the Study of the Presidency and Congress in Washington, D.C., a Clinical Professor at Georgetown and Tufts University Schools of Medicine, Chair of the Global Health Program at the Meridian International Center, and Senior Policy and Medical Advisor at amfAR, The Foundation for AIDS Research. Dr. Blumenthal served for more than 20 years in senior health leadership positions in the Federal government in the Administrations of four U.S. Presidents, including as Assistant Surgeon General of the United States, the first Deputy Assistant Secretary of Women's Health, as a White House Advisor on Health, and as Chief of the Behavioral Medicine and Basic Prevention Research Branch at the National Institutes of Health. Admiral Blumenthal has received numerous awards including honorary doctorates and has been decorated with the highest medals of the US Public Health Service for her pioneering leadership and significant contributions to advancing health in the United States and worldwide. She is the recipient of the 2009 Health Leader of the Year Award from the Commissioned Officers Association. Admiral Blumenthal was recently named a 2010 Rock Star of Science.

Sophie Turrell, a recent graduate of Yale University, is a Health Policy Research Associate at the Center for the Study of the Presidency and Congress in Washington, D.C.

Praveen Pendyala, a recent graduate of the University of California at Berkeley, serves as a Health Policy Fellow at the Center for the Study of Presidency and Congress in Washington D.C.

Katherine Warren, a student at Harvard University, serves as a Health Policy Intern at the Center for the Study of Presidency and Congress in Washington D.C.

Laura Macherelli, a student at the University of Maryland, serves as a Health Policy Intern at the Center for the Study of Presidency and Congress in Washington D.C.