October 1, 1999
THE SICKNESS

Risk Varies for Those Exposed
Related Article
  • Japanese Fuel Plant Spews Radiation After Accident
    By NICHOLAS WADE

    M inor doses of radiation released in the nuclear accident at the Tokaimura uranium processing plant are likely to have mild medical effects, but the worst amounts, affecting a few workers at the plant, could prove fatal.

    The two workers who were most exposed received a dose of 8 to 10 sieverts, or in the range of about 800 rads, to use two measures of radiation, according to estimates by a Japanese radiologist.

    "These are bad numbers," said Dr. Eugene L. Saenger, a retired professor at the University of Cincinnati and a leading authority on radiation medicine. "I would predict the dose would be lethal without some miracle."

    Serious injury from radiation is caused by doses of 100 or so rads and upward, and at 400 to 600 rads, half of those infected may die.

    Workers exposed to doses of 100 or more may face crises to the gastrointestinal tract and to the bone marrow.

    There is no specific treatment for radiation damage to the stomach lining, Dr. Saenger said, other than to replace the body fluids lost through bleeding. But damaged bone marrow can be treated with transplants.

    People exposed to doses of less than 300 rads would be expected to recover spontaneously, Dr. Saenger said, though they would often be given supportive therapy in the form of antibiotics.

    Japanese authorities reported that radiation around the plant was 10,000 or more times higher than normal, a figure that Dr. Saenger calculated was roughly equal to 10 rads.

    This is far higher than conventional exposures, such as medical procedures.

    Radioactive gases are said to have escaped from the plant, and these would present a variety of hazards.

    The most dangerous, Dr. Saenger said, would be iodine 131, a radioactive element.

    All forms of iodine are quickly taken up by the thyroid gland and radioactive iodine will damage it, with a risk of cancer.

    One safeguard is iodine pills, based on the principle that normal iodine will get to the thyroid first and block the radioactive iodine. The pills must be given as soon as possible, certainly within 24 hours of exposure, Dr. Saenger said.

    Pregnant women are at particular risk from iodine 131 because of damage to the fetus. Little is known about the doses that will cause genetic abnormalities in the fetus.

    Rads refer to the amount of radiation a body absorbs; another measure, rems, tracks damage to human tissue.

    Copyright 1999 The New York Times Company