Radiation is a form of energy that can exist as rays, waves or particles. Radiation causes changes in living cells resulting in biological effects. Humans are constantly exposed to radiation in the environment that comes from space and the ground. For people in the United States, this background radiation is usually too small, less than 300 mrem according to the United States Nuclear Regulatory Commission, to cause biological effects. Those exposed to additional radiation, through a job, cancer treatments or accidental exposure, such as the atomic bombs in Japan or the Chernobyl disaster, will experience a variety of biological effects.
Cancer
With normal radiation exposures, the effects on the body are usually too small to be detected as reported by the United States Nuclear Regulatory Commission. The body has an internal repair system that is able to repair damage caused by radiation to the cells. If this repair mechanism fails, then the damaged cells either die, which in the case of minimal exposure causes no further damage since cells die off every day, or the cells incorrectly repair themselves. In this case, the resulting change within the cell can cause cancer.
Cancer is the abnormal and uncontrollable growth of cells caused by an internal mutation (change) within the cell. The types of cancer most commonly associated with exposure to high doses of radiation, levels of 50,000 mrem or more, include breast, colon, leukemia, bladder, liver, lung, esophagus and ovarian. The cancer may develop years after the exposure, according to Science Encyclopedia, which is known as the latent effect.
Genetic Effects
When the reproductive cells of the body, the eggs or sperm, are exposed to radiation, changes within these cells can occur. These changes, or mutations, can result in genetic effects. The reproductive cells contain the DNA (deoxyribose nucleic acid) which carries the genes that code for all the traits. Changes or damage to this DNA is passed on to the offspring and can result in birth defects, stillbirths, congenital diseases or even death.
Acute Radiation Syndrome
In general, high doses of radiation tend to kill cells while the smaller doses induce changes within the cells. When a large number of cells die at once due to exposure to radiation acute radiation syndrome, also known as radiation sickness occurs. Since radiation affects each person differently, not everyone will have the same symptoms at the same level of exposure.
The cells of the digestive system are vulnerable to the effects of radiation. Therefore, the symptoms of nausea, blooding vomiting and diarrhea are often the first symptoms according to the doctors at the Mayo Clinic. The time between the exposure and the onset of the symptoms is dependent on the length and strength of the exposure. Other symptoms of acute radiation sickness include headache, fatigue, weakness, hair loss, infections and fever.
