The spectrum of radiation is divided between ionizing and nonionizing radiation and the distinction depends on the amount of energy carried by the radiation, which is directly proportional to the frequency of vibation of the elecric and magnetic fields. Ionizing radiation arises from X-rays and nuclear radiation and carries enough energy to remove an Electron from an atom and leave it positively charged. The energy released is enough to break DNA bonds which can lead to signifigant cellular damage or caner.
Nonionizing radiation has less energy and is less invasive than ionizing radiation. This radiation constantly surrounds us. Visible light from the sun, light bulbs, radio and television, ad electric appliances all contribute to background nonionizing radiation. For the most part, nonionizing radiation does not contain enough energy to damage cells, but repeated exposure (especially to sunlight) can be harmful.
Radiation has a wide range of health effects depending on the source, the type (ionizing radiation or nonionizing radiation), and the amount. However, the end result of many radiation exposures is severe cellualr damage and Cancer. Radiation is a perfect example of the dose-response relationship: the more radiation one receives, the greater ones chance of developing Cancer.
Both forms of radiation can result in cancer, but ionizing radiation is generally much more potent and harmful. Ionizing radiation carries enough energy to damage cells while only through extreme prolonged exposure can one develop cancer from nonionizing radiation and this is nearly always Skin Cancer.
Sources include: Radon, X-rays, radioactive meterial produce alpha, beta, and gamma radiation, cosmic rays from the sun and space
Solar radiation has obviously been around since the beginning of time because it is produced by the sun. It was discovered by Marie Curie in her Paris lab in 1898. Early investigation led many to believe that radiation had many positive therapeutic uses. Radium therapy was deemed safe by the American Medical Association and Radium was used to treat arthritis, stomach ailment, and Cancer, sadly what it has subsequently been known to cause.
The turn of the twentieth century, especially with the advent of electricity, marked the beginning of the modern understanding the potential effects of radiation. In 1901, Wilhelm Conrad Roentgen was awarded the first Nobel Prize in physics for discovering the x-ray and two years later Marie Curie along with Henri Becquerel were awarded the Nobel Prize in physics for their work on radiation. Enrico Fermi and his colleagues accomplished the first sustained nuclear reaction at the University of Chicago in 1942 and, because of this knowledge, two atomic bombs were dropped on the Japanese cities Hiroshima and Nagasaki, Japan.
Much of the understanding of the health effects of radiation result from tragic experiences associated with early exposure. Women, referred to as radium girls, were employed by the US Radium Corporation to paint Radium on watch dials. The women used their lips to point the brushes and every time they pointed they ingested a small dose of Radium Girls. The Radium Girls moved to the bone and began to damage cells in and around the bones causing a conspicuously high cancer rate among the women. Some of the women sued and received a small payment, becoming the first people to receive compensation for occupational injury.
Similarly, the health effects of nuclear radiation is understood from health affects associated with the dropping of the atomic bombs on Japan in the summer of 1945.
The first organized effort to protect people was in 1915 when the British Roentgen Society adopted a resolution to protect people from X-rays. The United States adopted the British system in 1922 and subsequently numerous groups were formed to protect people from radiation. In 1959, the Federal Radiation Council was formed to advise the president and recommend strategies. Now the Environmental Protection Agency ans several other government agencies are responsible for strategy.
U.S. National Academy of Sciences (NAS) established with the mission of the Committees on The Biological Effects of Atomic Radiation (BEAR) was to provide a thorough review of all that was known at the time about the effects of atomic radiation on living organisms. The Committees on BEAR had been put together in 1955 by then-NAS president Detlev Bronk in response to the increasing but uncoordinated accumulation of data on the effects of atomic radiation. (see NAS BEAR) - (more on the BEAR I Report - Toxipedia).
There are three ways to reduce exposure. First, limit the time spent near the source of radiation. Second, distance oneself from the source of radiation. Thirdly, shield yourself from the radiation. For example wear a hat or long clothing while exposed to the sun for long periods of time or request a lead apron while getting x-rayed. Heavier Alpha Particles can be stopped by a mere piece of paper but once they are inside they can do terrific cellular damage and nearly always cause Cancer.
Damage to the O-Zone Layer have increased the amount of UV rays that enter the atmosphere. The sunlight that people absorb are more harmful and the amount of kin cancer will rise.
The fundamental descriptive unit of ionizing radiation is the amount of energy, expressed in coulumbs per kilogram of air, and is the unit of absorbed dose in air. The absorbed dose is the amount of energy absorbed by a specific material, such as the human body, and is described as the gray(Gy). Recommended limits on radiation exposure is the sievert (Sv) which is the equivalent of the different particles and gamma rays.
European, Asian, and International Agencies
Clark, Claduia. Radium Girls: Women and Industrial Health Reform, 1910-1935. New York: University of North Carolina, 1997.
Gilbert, Steven G. A Small Dose of Toxicology: The Health Effects of Common Chemcials. New York: CRC Press, 2004.