The harmful effects of radiation on humans range from nausea and headache, which are triggered when the exposure is mild, to something as severe as genetic mutation and death.
Everybody knows that exposure to radiation can result in harmful effects on human health; courtesy, accidents like the Three Mile Island accident (1979) and the Chernobyl Disaster (1986). The severity of the effects of radiation on human body is determined by the amount of exposure, ability of the radiation to harm the organ tissue, organ that is affected, etc.
How Does Radiation Affect the Human Body?
When we talk about radiation, there exist two different types: ionizing radiation (which includes alpha particles, beta particles, neutrons, etc.), and non-ionizing radiation (which includes visible light, infrared waves, radio waves, thermal radiation, etc.). Ionizing radiation refers to any radiation which has the ability to displace electrons from atoms or molecules, which, in turn, results in production of ions. It is the exposure to this type of radiation that has adverse effects on the human body. The unit used to measure a person’s exposure to radiation is referred to as ‘rem’ (Roentgen equivalent in man). It is the total dose of radiation in rems, which determines how radiation would affect the body. Its harmful effects range from mild, such as nausea and hair loss, to severe, such as hemorrhage and cancer. Severe exposure can even result in death.
Mild Radiation Sickness
Even though radiation exposure of up to 100 rems doesn’t have any major implications of the body, temporary reduction in white blood cells is observed in some cases. Scientists also state that exposure as little as 20 rems can result in possible chromosomal damage in the long run. Exposure above 100 rems can result in mild radiation sickness; the symptoms of which start surfacing a few hours after the exposure. These include nausea, headache, diarrhea, fatigue, etc. The loss of white blood cells, which is much more prominent at this level of exposure, eventually hampers the resistance levels of the body and makes the person vulnerable to a range of health problems. Diagnosis of mild radiation sickness is difficult, as initial symptoms like flu and headache go unnoticed in most of the cases.
Severe Radiation Sickness
If the exposure is above 200 rems, the person will experience severe radiation sickness and may even suffer a hemorrhage. The person may also experience temporary hair loss in clumps. Approximately, 10 – 35 percent of those exposed to this amount of radiation end up dying. Any amount of exposure exceeding 300 rems can result in damage to bone marrow and small intestine. In this case, the chances of survival are even less, with half the people exposed to this level of radiation succumbing to its effects on various organs of the body within a period of 30 days. Furthermore, approximately 70 – 90 percent of the people who are exposed to radiation in excess of 400 rems end up dying as a result of organ failure.
Exposure above 1000 rems can have even more serious implications on the body. When the person is exposed to this level of radiation, the small blood vessels in the body are damaged, which invariably results in his death. The chances of survival are less than 10 percent. As the brain cells don’t reproduce, they don’t get damaged directly unless the person is exposed to radiation above 5000 rems. At this level of exposure, radiation kills the nerve cells and small blood vessels in the brain, which, in turn, causes seizures and results in death. All these effects of radiation on the basis of amount of exposure are based on studies. It is virtually impossible to say how much radiation dose the person has been exposed to, and that makes it even more difficult to deal with the situation.
Long Term Effects of Radiation Exposure
Radiation effects on DNA, wherein radiation exposure results in mutation of cells, is one of the most prominent effects of ionization radiation in the long run. The mutations in this case, can be teratogenic (which affects only the individual who was exposed) or genetic (the effects of which are passed on to the next generation). Radiation also results in changes to the genetic structure of the cells, which triggers abnormal cell growth and eventually results in formation of cancerous tumors. The aftereffects of Chernobyl disaster and Three Mile Island accident are seen even today, with several people still suffering from health problems that are attributed to radiation exposure from these incidents.
When we talk about radiation effects, we most often take into consideration the effects of nuclear radiation on humans. That being said, radiation caused by x-ray exposure and radiation therapy is also known to be harmful for the body. Therefore, there is a set limit up to which a person can be exposed to radiation even in the field of medicine. This limit is set with the objective of preventing acute exposure and limiting it to acceptable levels, as exposure beyond these limits can make the person vulnerable to various harmful effects of the same.