The Effects of Radiation Exposure
1. General Effects
Radiation is damaging to living cells. Having evolved on a planet where radiation is prevalent, however, the human body is capable of repairing damage caused by radiation. Small, brief exposures to radiation will kill cells, but millions of cells die in a healthy body every day already. A few more lost will not have an adverse effect. High doses of radiation overwhelm the body, destroying cells faster than the body can repair the damage. Illness or death can result. Low doses of radiation may be dangerous because rather than destroying cells, they cause damage to cell components like DNA, which can lead to adverse effects.
2. Large Dose
A large dose of radiation, the sort that would come from the fallout from a nuclear bomb or from a reactor meltdown, can lead to radiation sickness. This condition, called Acute Radiation Syndrome (ARS), will occur, according to the Centers for Disease Control and Prevention, only if all of the following conditions are met: the dose was high, the radiation was able to penetrate to the inner organs, the radiation affected most of the body and the exposure happened quickly, usually within a few minutes. Disasters such as the meltdown of the Chernobyl reactor in 1986 and the two atomic bombs dropped on Hiroshima and Nagasaki in 1945 produced ARS in their victims. ARS can also result from medicinal radiation exposure.
The early symptoms of ARS are vomiting, nausea and diarrhea, according to the Centers for Disease Control and Prevention. These can last anywhere from a few minutes to several days. After this, the person begins to feel better before relapsing into a stage of serious illness. This stage of illness can include loss of appetite, fatigue, fever, nausea, vomiting, diarrhea and possibly even seizures and coma, and may last from hours to months. The morbidity of ARS depends upon the severity and duration of the initial exposure. Most people who die of ARS die of infection and internal bleeding caused by damage to the bone marrow.
In laboratory trials on test animals, high doses of radiation have caused mutations, according to the Nuclear Regulatory Council, but no comparable trends have been observed in the children of the survivors of Hiroshima and Nagasaki.
3. Sustained Small Doses
According to the Nuclear Regulatory Council, the data on the effects of small, sustained doses of radiation are inconclusive. While large exposures have been shown to increase the risk of developing cancer, studies on small dose exposure do not show a conclusive causal link. Nevertheless, the Nuclear Regulatory Council and the larger international scientific community assume that low dose radiation exposure may cause cancer or other health risks. The NRC and other organizations have established safe exposure guidelines, drawn along conservative estimates of tolerance and effect, for workplace and public safety.
4. Risk to Unborn Infants
According to the CDC, unborn infants are especially susceptible to radiation exposure, particularly during the early stages of gestation. As the pregnancy progresses, the infant becomes increasingly resistant to radiation. Conversely, during the first 15 weeks of pregnancy, radiation exposure may lead to birth defects and a higher risk of developing cancer later in life, even at levels that will have no visible effect on the mother. Its position inside the mother's womb partially shields the infant from radiation exposure; it will not receive the same dose of radiation from external sources that the mother will. If the mother accidentally ingests or inhales radioactive material, this will be transferred to the infant via the bloodstream. The CDC advises expectant mothers who are concerned about radiation exposure to their unborn children to seek medical counsel.
5. Sources of Exposure
The vast majority of radiation sources any of us will encounter in our lifetimes are not likely to cause any severe damage. With the exception of pregnant women, there is little reason to be concerned about low dose exposures such as medical X-rays. Sources of extremely high doses of radiation, such as nuclear weapons and the meltdown of nuclear power plants, have been rare occurrences in history. The most likely source of radiation exposure that will have a noticeable effect on a human being will come in the form of medicinal radiation treatment.
Source: ehow
