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HUMAN HEALTH AND RADIATION: IONIZING RADIATION
Exposure to ionizing radiation is an inescapable part of life on this planet. Ionizing radiation is caused by the release of particles and electromagnetic rays from atomic nuclei during the normal process of disintegration. Some naturally occurring elements, such as uranium, emit radiation. Radiation can wreak havoc on human cells, leading to mutations, cancer, miscarriages, and other problems.
Reactions to radiation differ from person to person. Exposure is measured in radiation absorbed doses, or rads (also called roentgens). Recommended maximum \"safe\" dosages range from 0.5 rads to 5 rads per year. Approximately 50 percent of the radiation to which we are exposed comes from natural sources, such as building materials. Another 45 percent comes from medical and dental X-rays. The remaining 5 percent comes from computer display screens, microwave ovens, television sets, luminous watch dials, and radar screens and waves. Most of us are exposed to far less radiation than the \"safe\" maximum dosage per year.
Radiation can cause damage at dosages as low as 100 to 200 rads. At this level, signs of radiation sickness include nausea, diarrhea, fatigue, anemia, sore throat, and hair loss. Death is unlikely at this dosage. At 350 to 500 rads, all these symptoms become more severe, and death may result because the radiation hinders bone marrow production of the white blood cells we need to protect us from disease. Dosages above 600 to 700 rads are invariably fatal. The effects of long-term exposure to relatively low levels of radiation are unknown. Some scientists believe that such exposure can cause lung cancer, leukemia, skin cancer, bone cancer, and skeletal deformities.
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GENERAL HEALTH
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