Radiation & Nuclear Topics FAQ

 

What is radiation?

Radiation is a form of energy that is present all around us. Different types of radiation exist; some of which have more energy than others.

Ionizing radiation is a form of energy released by atoms in the form of electromagnetic waves or particles. This type of energy has enough energy to remove electrons from atoms, thereby ionizing them. When unstable elements disintegrate, they emit ionizing radiation. Types of ionizing radiation include gamma rays, X-rays, and cosmic rays.

Non-ionizing radiation is a form of energy that has less energy than ionizing radiation and does not have enough energy to remove electrons from atoms. Types of non-ionizing radiation include radiowaves, microwaves, infrared radiation, and visible light.

What is radiation exposure?

Radiation exposure is when a person is exposed to some type of ionizing radiation in which energy penetrates the body. There are two types of exposure: internal and external.

Internal exposure occurs when radioactive material enters the body. The ways in which these particles can enter the body include inhalation, ingestion, absorption, or through cuts in the skin. Internal exposure continues until the material is eliminated from the body, either naturally or as a result of medical intervention.

External exposure occurs when radioactive material is deposited on the skin or clothes. In this case, exposure will continue until the radioactive material is removed.

External exposure can also result from irradiation from an external source. The exposure stops when that person is outside of the radiation field or is shielded from the source of radiation. For example, when a person has an x-ray, they are externally exposed to radiation for a very short period.

How can exposure occur?

People are exposed to tiny amounts of radiation every day, both from naturally occurring sources (such as elements in the soil or cosmic rays from the sun) and man-made sources. Man-made sources include medical sources (such as x-rays, certain diagnostic tests and treatments) and from nuclear power generation.

The amount of radiation from natural or man-made sources to which people are exposed is usually very small. During radiological emergencies, such as a nuclear power plant accident or a terrorist event, people could become exposed to different doses of radiation, depending on the situation.

Scientists estimate that the average person in the United States receives a dose of about one-third (2/3) of a rem, or about 620 millirem, per year. About 50% of human exposure comes from natural sources and the remaining 49% comes from man-made radiation sources mainly medical x-rays.

What happens when people are exposed to radiation?

Radiation can affect the body in several ways. If the absorbed dose is sufficiently high, a variety of adverse health effects can result.

These adverse health effects can range from mild effects, such as skin reddening, to serious effects such as cancer and death; depending on the amount of radiation absorbed by the body (the dose), the type of radiation, the means of exposure, and the length of time a person was exposed.

Any living tissue in the human body can be damaged by ionizing radiation. The body attempts to repair the damage, but sometimes the damage is too severe or widespread. Exposure to very large doses of radiation may cause death within a few days or months.

Chronic exposure to lower doses of radiation may lead to an increased risk of developing cancer or other adverse health effects later in life.

For more information about radiation, check the following websites:

How can I minimize radiation exposure?

There are key three components to consider in minimizing your radiation exposure. They are time, distance and shielding.

Time: By limiting the amount of time you spend near a radiation source you can reduce the amount of radiation exposure that you will receive.

Distance: The greater the distance between you and the radiation source, the less radiation exposure you will receive.

Shielding: The more heavy and dense the material between you and the source of the radiation the better. The shielding will block much of the radiation from reaching you.

What is radioactive contamination?

Radioactive contamination is when a person or object has radioactive material either internally or externally. Radioactive materials released into the environment can cause contamination of air, water, surfaces, soil, plants, buildings, people and/or animals.

How does contamination differ from exposure?

Contamination refers to particles of radioactive material that are deposited anywhere that they are not supposed to be; such as on an object, on a person's skin, or even internally. There are two types of contamination: External contamination and internal contamination.

External contamination on humans occurs when radioactive material, in the form of dust, powder, or liquid, comes into contact with a person’s skin, hair, or clothing (any contact outside of the body). With external contamination, you are being exposed to ionizing radiation as long as the radioactive material is present. External contamination can be removed through a decontamination process.

One risk of external contamination is the possibility of spreading the contamination. It is similar to touching wet paint and then touching another surface. You will carry some of that wet paint with you to the next surface. The paint will stay on you and those surfaces until it is removed.

Internal contamination occurs when radioactive materials are ingested, inhaled, or when these materials enter the body through an open wound. They can even be absorbed through the skin. Some types of radioactive materials stay in the body and are deposited in different body organs. Other types are eliminated from the body in blood, sweat, urine and feces.

Radioactive contamination emits radiation. If a person is contaminated, they will continue to be exposed to radiation until the contamination is removed.

However, a person can be exposed to radiation and not become contaminated. Take an x-ray for example. An x-ray exposes parts of the body to radiation so that an internal picture can be taken – so that we can know what is going on inside. While an x-ray exposes you to radiation, there is nothing “left over” on the surface of the skin or body after the x-ray is over, so therefore you would not be contaminated.

How is radioactive contamination spread?

People who are externally contaminated with radioactive material can contaminate other people through physical contact. Homes and other places can also become contaminated with radioactive materials from direct contact with a person who is externally contaminated.

People who are internally contaminated can expose people near them to radiation from the radioactive material inside their bodies. The body fluids (blood, sweat, urine) of an internally contaminated person can contain radioactive materials. Coming in contact with these body fluids can result in contamination and/or exposure.

How can exposure or contamination happen?

Man-made radioactive materials could be released into the environment in the following ways:

  • An accidental release from a medical or industrial device.
  • A nuclear power plant accident.
  • An atomic bomb explosion.
  • Nuclear weapons testing.
  • An intentional release of radioactive material as an act of terrorism.

How is radioactive material contamination cleaned up?

When safe, or directed to do so, get out of the immediate area of the radiological incident. Go inside the nearest safe building or to the area to health officials or emergency management officials direct you.

Remove the outer layer of your clothing. If radioactive material is on your clothes, getting it away from you will reduce the external contamination and decrease the risk of internal contamination. It will also reduce the length of time that you are exposed to radiation.

Place the clothing in a plastic bag or leave it in an out-of-the-way area. Keep people away from it to reduce their exposure to radiation. Keep cuts and abrasions covered when handling contaminated items to avoid getting radioactive material in them.

Wash all the exposed parts of your body using lots of soap and water to remove contamination.

If medical authorities determine that internal contamination may have occurred, you may be able to take medication to reduce the radioactive material in your body.

Be on the lookout for information. Once health officials assess the scene and the damage, they will be able to tell people whether or not radiation was involved in the incident.

How can I limit the chances of becoming contaminated?

When safe, or directed to do so, get out of the immediate area of the radiation incident. Go inside the nearest safe building or to the area to health officials or emergency management officials direct you.

Remove the outer layer of your clothing. If radioactive material is on your clothes, getting it away from you will reduce the external contamination and decrease the risk of internal contamination. It will also reduce the length of time that you are exposed to radiation.

Place the clothing in a plastic bag or leave it in an out-of-the-way area. Keep people away from it to reduce their exposure to radiation. Keep cuts and abrasions covered when handling contaminated items to avoid getting radioactive material in them.

Wash all of the exposed parts of your body using lots of soap and water to remove contamination.

If medical authorities determine that internal contamination may have occurred, you may be able to take medication to reduce the radioactive material in your body.

Be on the lookout for information. Once health officials assess the scene and the damage, they will be able to tell people whether or not radiation was involved in the incident.

How are radiation exposure victims medically treated?

There is no “one-size-fits-all” treatment for all exposures to radiation. Medical personnel will treat victims for physical injuries first (such as cuts, broken bones, trauma, hemorrhage and shock, etc.). Open wounds are usually cleaned to remove any bits of radioactive materials that may be in them. Amputation of limbs may occur if a wound is highly contaminated and recovery of its function is not likely.

If radioactive material is ingested, treatment is given to reduce absorption into the body and enhance body’s natural elimination processes (excretion and elimination). It can include stomach pumping or giving the victim laxatives or aluminum antacids.

If radioactive material has gotten into internal organs and/or tissues, treatment includes giving the patient blocking and diluting agents, such as Potassium Iodide, to decrease absorption into the body. Other chemicals such as ammonium chloride, diuretics, expectorants and inhalants are given to a patient to force the body to release the harmful radioactive materials. Other treatments involve chelating agents, which, when ingested, bind with some radioactive metals to form a stable material that is more easily removed from the body through the kidneys.

In the event you suspect you have been exposed to radiation, DO NOT ATTEMPT TO TREAT YOURSELF. See a doctor immediately.

Is any amount of radiation safe?

Some scientists believe that low levels of radiation are beneficial to health (known as hormesis). However, there do appear to be thresholds of exposures for various health effects, for example:

  • Up to 10 Rem (10,000 mrem*) no effect (plus there remains little to no lasting effect).
  • At 50 Rem nausea may occur, but there are no lasting effects.
  • At 70 Rem vomiting may occurs, but again there are few, if any, lasting effects.
  • Between 300-to-500 Rem, radiation sickness can occur, and can be fatal without medical intervention
    • Mild symptoms include: fatigue, loss of appetite, severe nausea, vomiting and fever.
    • Severe symptoms include: fatigue, loss of appetite, severe nausea, vomiting, fever, diarrhea, inflamed mouth and throat and hair loss.
  • At 600 Rem, or higher, death occurs.

Examples are based on adult exposure. Children, the elderly and those with compromised immune systems, are more susceptible to excessive radiation exposure and may show more serious symptoms at lower levels of exposure.

What are some of the most common sources of radiation?

Whole body CT 1,000 mrem* per exam
Upper gastrointestinal X-ray 600 mrem* per exam
Radon in average U.S. home 228 mrem* per year Roland
Head CT 200 mrem* per exam
Cosmic Radiation living in Denver 80 mrem* per year
Radiation in the body 29 mrem* per year
Terrestrial radioactivity 21 mrem* per year
Chest X-Ray 10 mrem* per exam
Living near a nuclear power station <1 mrem* per year

Source: Environmental Protection Agency

*mrem – mrem (the abbreviation for millirem) is an extremely small measure of ionizing radiation absorbed by the body; much like millimeter is an extremely small measure of length. These amounts are well within what is acceptable and not harmful to health or life.

What is radiation sickness?

Radiation sickness, known as acute radiation syndrome (ARS), is a serious illness that occurs when the entire body (or most of it) receives a high dose of radiation, usually over a short period of time.

People exposed to radiation will get ARS only if:

  • The radiation dose was high (greater than 70 rem).
  • The radiation was able to reach internal organs.
  • The person’s entire body (or most of it) received the dose.
  • The radiation was received in a short time, usually within minutes.

The first symptoms of ARS typically are nausea, vomiting and diarrhea. These symptoms will start within minutes to days after the exposure. The symptoms may come and go. The person usually looks and feels healthy for a short time, after which he or she will become sick again with loss of appetite, fatigue, fever, nausea, vomiting, diarrhea and possibly even seizures and coma. This stage may last from a few hours up to several months.

People with ARS usually have some skin damage that can start to show within a few hours after exposure. This damage can include swelling, itching and redness of the skin (like a bad sunburn). There can also be hair loss, nausea and diarrhea. As with the other symptoms, the skin may heal for a short time, followed by the return of swelling, itching and redness days or weeks later. Complete healing of the skin may take from several weeks to a few years depending on the radiation dose to the skin.

The chance of survival for people with ARS decreases with increasing radiation doses. Most people who do not recover from ARS will die within several months of exposure. The cause of death in most cases is the destruction of the person's bone marrow, which results in infections and internal bleeding. For the survivors of higher doses, the recovery process may last from several weeks to two years.

If a radiation emergency occurs that exposes people to high doses of radiation in a short period of time, they should immediately seek medical care from their doctor or local hospital.

How do we know radiation causes cancer?

We have learned through observation. Scientists didn’t understand that there were any health effects associated with radioactive materials when people first began working with them. As the use of radioactive materials and reports of illnesses became more frequent, scientists noticed a pattern to the illnesses. People working with radioactive materials and x-rays developed particular types of uncommon medical conditions. Among the best known long-term studies are those of Japanese atomic bomb blast survivors, other populations exposed to nuclear testing fallout (natives of the Marshall Islands for example) and Uranium miners.

Do chemical properties of radioactive materials contribute to radiation health effects?

The chemical properties of a radionuclide can determine where health effects occur. To function properly many organs require certain elements. The organs cannot distinguish between radioactive and non-radioactive forms of the element and the body will try to absorb or accumulate one just as quickly as the other. For example:

  • Radioactive Iodine concentrates in the thyroid. The thyroid needs Iodine to function normally. As a result, radioactive Iodine contributes to thyroid cancer more than any other types of cancer.
  • Calcium, Strontium-90 and Radium-226 have similar chemical properties. The result is that Strontium and Radium tend to collect in Calcium rich areas of the body, such as the bones and teeth. Therefore, the Strontium-90 and Radium-226 can contribute to bone cancer.

What is the cancer risk from radiation? How does it compare to the risk from other sources?

Currently estimates are that overall, if each person in a group of 10,000 people exposed to one (1) Rem of ionizing radiation, in small doses over a life time, we would expect five or six more people to die of cancer than would otherwise. In this group of 10,000 people, we can expect about 2,000 to die of cancer from all non-radiation causes.

Are children more sensitive to radiation than adults?

Yes, because children are growing more rapidly, there are more cells dividing and a greater opportunity for radiation to disrupt the process. Fetuses, depending on their stage of development, can also be highly sensitive to radiation.

What is prenatal radiation exposure?

It is the exposure of an unborn baby to radiation. This can occur when the mother’s abdomen is exposed to radiation, either externally or internally. Also, radioactive materials may enter the mother’s bloodstream if a pregnant woman accidentally swallows or breathes in radioactive materials. From the mother's blood, radioactive materials may pass through the umbilical cord to the baby.

Unborn babies are less sensitive during some stages of pregnancy than others. However, unborn babies are particularly sensitive to radiation during their early development, between the second and fifteenth weeks of pregnancy. The health consequences can be severe, even if radiation doses are too low to make the mother sick. Such consequences can include stunted growth, deformities, abnormal brain function, or cancer that may develop sometime later in life. The radiation dose to the unborn baby is usually lower than the dose to the mother for most radiation exposure events.

Pregnant women should consult with their doctors if they have any concern about radiation exposure to their unborn baby.

What are the possible health effects that an unborn baby could experience when exposed to ionizing radiation?

During the first two weeks of pregnancy, the radiation-related health effect of greatest concern is the death of the baby. Of the babies that survive, some will have birth defects related to the exposure, regardless of how much radiation they were exposed to.

Large radiation doses to the unborn baby during the stages of development (between the second and 15th weeks of pregnancy) can cause birth defects, especially to the brain. Babies exposed to the atomic bombs dropped on Hiroshima and Nagasaki during the 8th to 15th week stage of pregnancy were found to have a high rate of brain damage that resulted in lower IQ and even severe mental retardation. They also suffered stunted growth (up to 4% shorter than average people) and an increased risk of other birth defects.

Between the 16th week of pregnancy and birth, health effects due to radiation exposure are unlikely unless the unborn baby receives an extremely large dose of radiation. In the 16th to 25th week of pregnancy, health consequences similar to those seen in the 8th to 15th week could occur, but only when the doses are extremely large (more than the equivalent of about 5,000 chest x-rays received at one time). At this dose level, the mother could also be showing signs of acute radiation syndrome.

After the 26th week of pregnancy, the radiation sensitivity of the unborn baby is similar to that of a newborn. Unborn babies exposed to radiation during this stage of pregnancy are no more sensitive to the effects of radiation than are newborns. This means that birth defects are not likely to occur and only a slight increase in the risk of having cancer later in life is expected.

What are the possible genetic effects due to radiation exposure?

Genetic effects are mutations that can be passed from parent to child or mutations that occur in the person exposed. They can include: stunted growth, small head/brain size, developmental concerns and childhood cancers.

People who are internally contaminated can expose people near them to radiation from the radioactive material inside their bodies. The body fluids (blood, sweat, urine) of an internally contaminated person can contain radioactive materials. Coming in contact with these body fluids can result in contamination and/or exposure.

What are the possible genetic effects due to radiation exposure?

Genetic effects are mutations that can be passed from parent to child or mutations that occur in the person exposed. They can include: stunted growth, small head/brain size, developmental concerns and childhood cancers.

People who are internally contaminated can expose people near them to radiation from the radioactive material inside their bodies. The body fluids (blood, sweat, urine) of an internally contaminated person can contain radioactive materials. Coming in contact with these body fluids can result in contamination and/or exposure.

What preparations can I make for a radiation emergency?

You should know that planning for a radiation emergency is similar to planning for hurricanes, earthquakes and other emergencies. Local, State and Federal agencies plan and practice responses to worst-case nuclear incidents just like they plan for hurricanes, earthquakes, dam failures and much more.

Whether you live within the 10-mile EPZ or outside of it, your community should have a plan in place in case of a radiation emergency. Check with community leaders to learn more about the plan and possible evacuation routes.

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.

Develop your own family emergency plan so that every family member knows what to do in the event of a nuclear emergency.

At home, put together an emergency kit that would be appropriate for any emergency. (see last page for possible emergency kit items to consider).

For more information about preparing for a radiation emergency event, check the following websites:

How can I protect myself during a radiation emergency?

The most appropriate action will depend on the situation. When emergency sirens sound around the plant and Emergency Alert System (EAS) messages go out to the public, you will be directed to tune to local news stations for information and instructions during any emergency.

After a release of radioactive materials, DHEC public health officials will test and monitor the levels of radiation and determine what protective actions to take.

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 place at your home or office.

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 to re-circulate air that is already in the building; such as indoor fans.
  • Close fireplace dampers.
  • If possible, bring pets and animals inside. For more information what to do to protect pets and farm animals and livestock, click here:
  • Move everyone to an inner room or basement
  • Keep your radio and/or television tuned to emergency channels or local news to find out what additional actions you will have to take. Information will be sent out via the Emergency Alert System messages as well.

If you are advised to evacuate, follow the directions that your local officials provide and proceed to the nearest available shelter or relocation center. Even if you plan to stay at a hotel or with friends/family, rather than a shelter, GO TO THE SHELTER OR RELOCATION CENTER FIRST so you can be accounted for and checked and/or monitored for radiation exposure.

If advised to evacuate, leave the area quickly but in an orderly manner. Do not panic. In addition:

  • Take a flashlight, portable radio, batteries, first-aid kit, supply of sealed food and water, hand-operated can opener, essential medicines 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 may not accept animals. If evacuating with a pet, take the pet with you to the shelter or relocation center to be checked and monitored for radiation exposure. Then, once cleared, proceed to the place you want to stay (hotel, motel, shelter, with family, with friends, etc.).
  • Get a list of pet-friendly hotels and motels:

For more information about preparing for a radiation emergency event, check the following websites:

Should I take Potassium Iodide (KI) during a radiation emergency?

Potassium iodide (KI) should only be taken in a radiation emergency that involves the release of radioactive iodine; such as an accident at a nuclear power plant or the explosion of a nuclear bomb containing radioactive iodine. A "dirty bomb" most likely will not contain radioactive iodine. Public health officials will tell you when to take KI. Do not take it until or unless ordered.

A person who is internally exposed to radioactive iodine may experience thyroid disease or thyroid cancer later in life. Without KI, the thyroid gland could absorb enough radioactive iodine to cause an exposed person to develop cancer or abnormal growths later in life. KI will fill the thyroid gland with a non-radioactive form of iodine, decreasing the amount of harmful radioactive iodine that can be absorbed.

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 potassium iodide.

For more information about KI, check the following websites:

 

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Radiation & Nuclear Safety