How Much Is Too Much?

Almost as soon as the accident at Three Mile Island occurred, Radiation Physicist Ernest Sternglass was at the scene, Geiger counter in hand, crying disaster to anyone who would listen. He predicted an increase of 5% to 20% in the incidence of leukemia in children of the area within a year. A vehement foe of nuclear power, the University of Pittsburgh scientist exclaimed: "The reaction of the community should be to stand up and scream!"

Sternglass's warning was exaggerated. But no one--not even radiation experts--can say for sure that he is totally wrong. Despite science's long experience with radiation and bitter knowledge of its risks, like the cancers inflicted on early radium workers, including Madame Curie, disturbingly little is known about how much radiation, or what length of exposure, is safe for humans.

Radiation, whether natural or manmade, is ubiquitous. Over a year's time, the average American is exposed to 100 to 200 millirems. This is roughly equivalent to the exposure from 10 to 20 chest X rays. About half of that radiation comes from the sun and cosmic rays, another 45% from exposure to diagnostic and therapeutic medical equipment, and only about 5% from atomic fallout and such consumer products as microwave ovens and TV sets and production of nuclear power. Radiation sickness is almost certain at exposures of around 50,000 millirems. The Government has set a permissible annual level of radiation exposure for the general public of 500 millirems and for nuclear power plant workers 5,000 millirems. But these standards have been sharply questioned by radiation biologists, physicians and other scientists, and the Government is now reviewing its policy.

Most of what is known about the dangers of radiation comes from studies of people exposed to extremely high levels, such as the survivors of the A-bombs dropped on Hiroshima and Nagasaki and patients who were massively dosed with X rays for ailments now no longer treated in this way.

Problems that eventually surfaced, sometimes after 20 or 30 years, included clouding of the lens of the eye, leukemia, thyroid cancer, and changes in the genetic material. Particularly vulnerable are fetuses, primarily during their first three months of development, and children under ten.

More recently, studies, whose validity has been hotly debated, have suggested similarly troubling effects, especially high incidences of leukemia, among people who were exposed to considerably lower levels of radiation. Among the possible victims: residents of Arizona, Nevada and Utah who witnessed early atomic tests in the atmosphere and were showered with fallout, and workers in nuclear shipyards. In fact, many experts now believe any radiation carries with it some risks, as yet undefined, that may take years to show up. As Harvard University's Nobel-Prizewinning Biologist George Wald, an antinuclear activist, puts it: "Every dose is an overdose. There is no threshold where radiation is concerned. A little radiation does a little harm; a lot does more harm."

Not everyone agrees. Says Epidemiologist Robert Miller of the National Cancer Institute, who has studied the Hiroshima victims: "If it is possible to avoid radiation, you should do so. But the Pennsylvania doses being talked about are so low that they could not induce cancer in man. Even children and fetuses would be unaffected." Also, the Environmental Protection Agency says that the emissions from the Three Mile Island plant involved only the inert gases krypton and xenon, which are thought to cause little damage to tissue, and not particles of radioactive iodine and strontium, both of which can enter the food chain. Radiation Biologist and Pediatrician Robert Brent of Philadelphia's Jefferson Medical College agrees that the health risks are small, but says that "one of the worst effects is that people are afraid."

That fear is already evident. In Boston last week, after listening to a group of antinuclear physicians proclaim the hazards of radiation in a series of papers, a young woman whose husband had to go to Harrisburg on business stood up and addressed the panel. Said she: "I don't want him to go, but he says it's his job. We're having a big fight." Would he be safe? she asked the physicians. None could give her a firm answer.

This file is automatically generated by a robot program, so viewer discretion is required.