About Radiation
Radiation Basics
An atom is made up of protons (positively charged) and neutrons (no charge) in a nucleus, with electrons (negatively charged) orbiting around the nucleus. Most of the mass of an atom resides in the nucleus. The chemical element is determined by the number of protons in the atom. Atoms with the same amount of protons, but differing numbers of neutrons are called nuclides or isotopes. Isotopes that are unstable are radioactive and emit ionizing radiation.
There are two basic groups of ionizing radiation, particle and photon. Alpha, beta, and neutron radiation are all types of particle radiation in which a particle is emitted from the radioactive atom. Gamma and x-rays are two types of photon radiation in which a wave or ray (with no mass) is expelled from a radioactive atom. Alpha radiation consists of two protons and two neutrons and is relatively large and heavy. Alpha radiation travels a short distance will not penetrate most objects including a sheet of paper. Beta radiation consists of an electron expelled from an atom and is relatively small and fast. Beta radiation will travel moderate distances and has moderate penetrative abilities, but can be stopped by a sheet of aluminum. Gamma radiation consists of a ray and has no mass or charge. Gamma rays travel at the speed of light and will penetrate deeply into most objects.
Radiation occurs naturally all around us and even within us. The most common natural source of radiation is radon, but other natural sources include cosmic radiation, terrestrial radiation, and internal sources of radiation. Radiation can also be man-made, with the most common source being x-rays and other medical sources. The average person accumulates about 360 millirem/year, of which 82% is naturally occurring.
Radiation Basics (Requires Adobe Acrobat Reader)
Understanding Radiation from the Nuclear Energy Institute (Requires Adobe Acrobat Reader)
Health Effects of Radiation
Ionizing radiation can damage cells in human tissue in a unique way. The human body is capable of repairing most damage, but significant doses of radiation overwhelm the body's ability to repair cells and permanent damage can occur. These damaged cells can lead to noticeable health effects. Health effects can be split into two categories: stochastic and non-stochastic. Stochastic health effects are associated with long-term low level (chronic) exposure to radiation. Increased levels of exposure result in the likelihood of stochastic health effects increasing, but not the severity of said effects. The most common stochastic effect is cancer although other effects such as cell mutations can occur. These cell mutations can be teratogenic (affecting only the exposed fetus or individual) or genetic (able to be passed to offspring). Non-stochastic health effects appear after large doses of radiation and are dependent upon the size of the dose. These health effects are commonly called acute effects and can include nausea, weakness, hair loss, burns, and even death.
Exposure to radiation can occur along three common pathways: ingestion of radioactive material through contaminated food or water, injection of radioactive material through contaminated medical equipment, or inhalation of radioactive material. Some exposure to radioactive materials can be treated by radiopharmaceuticals that are designed for specific radioactive isotopes (such as Potassium Iodide for radioactive iodine or Prussian Blue for radioactive cesium). The effectiveness of these treatments is highly dependent on the amount of exposure and the relative time delay in treatment.
Health Effects of Radiation (Requires Adobe Acrobat Reader)
Radiation Doses in Perspective (Requires Adobe Acrobat Reader)
Radiation Safety for the First Responder
Three basic principles protect the safety of the first responder when responding to any radiological emergency: time, distance, and shielding. First responders have access to various personal protective equipment from the highest level (A) to lower levels (D) that include basic work clothing. Most first responders will commonly use Level C personal protective equipment such as tyvek coveralls and respirator or turnout (bunker) gear for firefighters. First responders must remember to use the appropriate level of protective gear for each unique emergency. The three basic principles or radiation safety are supplemented with three inital response actions. Safety, Isolate, and Notify or SIN serve to protect not only first responders, but the general public. Safety should be the first priority and always a concern with first responders remembering to stay upwind and upslope and consulting appropriate guidance. Isolation of the area and denying entry to all unneccesary personnel help reduce the spread of any potential contamination. Finally, first responders should remember to notify all appropriate agencies, such as the local HazMat team, local and state emergency management, environmental and health agencies, agricultural agencies, and neighboring jurisdictions.
West Virginia uses the established limits from the United State Environmental Protection Agency for emergency workers. Each emergency worker is limited to a dose of 5 rem, except in certain situations. The state does not allow declared pregnant workers to work in radiological emergencies.
Radiation Safety for the First Responder (Requires Adobe Acrobat Reader)
Measuring Radiation and Equipment (Requires Adobe Acrobat Reader)