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Nuclear Radiation Effects on Humans

According to the website Alternate Energy Sources, nuclear radiation is the emission through space and physical objects of electromagnetic energy waves of the following type: radio waves, infrared waves, visible light, ultraviolet waves, X-ray, gamma rays and cosmic rays. According to the U.S. Nuclear Regulatory Commission (NRC), humans are continually subjected to nuclear radiation from natural and human-made sources with no ill effect. However, higher doses of radiation, or constant exposure to lower doses, can affect human health.

  1. High Doses

    • Exposure to high doses of radiation--at least 80 rem--kills human cells, damaging tissue and organs immediately. This anatomical response, referred to as “acute radiation syndrome,” was seen in many atomic bomb survivors in 1945 and about 134 plant workers and firefighters in Chernobyl, Ukraine, the site of the world's worst nuclear power plant disaster. Of the 134 workers, exposure rates of 80 rem to 1,600 rem killed 28 within three months of the accident. Exposures up to100 rem can damage the stomach lining, interfering with its water and nutrient intake function. The immune system sustains damage at exposure rates up to 300 rem, subjecting the subject to infection and disease, and exposures of 400 rem and above are expected to kill 50 percent of subjects within 60 days of exposure, largely due to infection.

    Lower Doses

    • Exposure to lower doses of nuclear radiation--less than10 rem--can have a cumulative effect on human cells. Though no immediate cell damage is apparent at these dosage levels, continued exposure for long periods can change the structure of the cell. It usually takes five to 20 years for appreciable change to occur, with the main health concerns being cancers and abnormal genetic mutation. Radiation-altered genes can cause stillbirths, congenital abnormalities, infant mortality, decreased birth weight and childhood mortality. Genetic effects due to radiation exposure can be passed on to the exposed person’s children, or can affect children born several generations later. Exposure to nuclear radiation is five times more likely to cause cancer than genetic alteration. No evidence of genetic mutation was found in the offspring of Hiroshima or Nagasaki atomic bomb survivors.

    Non-Cancer Diseases

    • According to a 1998 Radiation Effects Research Foundation study on atomic bomb survivors, a number of noncancer diseases are caused by radiation exposure, as well. The study found a higher incidence of hypertension and myocardial infarction, noncancerous thyroid disease, cataracts, chronic liver disease, uterine, kidney and ureter disease in the study’s subjects, as compared to nonexposed individuals. Although a direct causal relationship between radiation exposure and heart disease has been proven, the evidence linking radiation exposure and other diseases largely remains statistical.

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