Workers and nearby residents who survived the explosion at a Soviet nuclear power plant near Kiev may suffer a wide variety of radiation effects ranging from superficial burns to delayed deaths from bleeding, infection or cancer, according to U.S. experts.
Reports on the number of persons killed in the disaster range from two to more than 2,000. But radiation experts in this country speculate that however many deaths may already have occurred, a far greater number of persons likely are at risk of dying.
Radiation sickness results chiefly from the effects that large doses of radiation have on the bone marrow and the gastrointestinal tract. Additionally, those exposed to radioactive fallout run a greater risk of developing cancer.
The effects on any given individual depend on the dose and type of radiation and whether the exposure is to the whole body or only to a part of it.
The standard measure of radiation is a rem, the amount of radiation required to produce a particular amount of damage to human tissue, and acute radiation sickness occurs at about 100 rems, according to physicians. Slight changes in the blood appear between 5 and 50 rems; more serious blood changes, as well as nausea and fatigue, between 50 and 100 rems. About 1% of persons who receive 100 to 200 rems die. A dose of 450 to 700 rems is lethal within one month to 50% of the individuals receiving it.
All persons who receive 700 to 1,000 rems commonly die within days or weeks, according to authorities.
Deaths from radiation sickness can occur days or even weeks after exposure and commonly result from bleeding or infection from radiation’s damaging effect on bone marrow, the part of the body that produces many components of blood and the immune system.
Deaths from cancer may not occur until years after the radiation exposure. The cancers are due to the slow transformation of cells that is the result of radiation’s effect on the cells’ genetic material.
In addition, exposure of expectant mothers can result in birth defects in unborn children. Children conceived after radiation exposure to one or both parents also may suffer birth defects.
Scientists have argued for many years over whether a safe level of radiation exists. Many believe that no such “threshold” exists, and that even the lowest possible level will have some effect on the cancer incidence.
The average American receives a dose of about 100 millirems a year due to natural background radiation, according to the U.S. Nuclear Regulatory Commission. A millirem is 1/1,000th of a rem.
In addition, the average person receives another 90 millirems a year from medical exposures such as X-rays, and smaller amounts from natural radiation in building material and remaining fallout from old weapons tests, bringing the annual total to about 200 millirems.
According to the NRC, the maximum safe exposure is 2 millirems in any hour, or 100 millirems in any seven consecutive days.
Residents of Denmark were reported buying potassium iodide tablets from pharmacies in an effort to protect themselves from the damaging effects of radioactive iodine that they fear may be part of the fallout carried by winds from the Soviet accident site. In Poland, the tablets were being given to children in some areas.
Iodine accumulates in the thyroid gland and radioactive iodine that concentrates there can cause cancer. Saturating the thyroid with harmless potassium iodide leaves no room for the radioactive iodine to get in, according to Dr. Joseph F. Ross, a UCLA physician who is president of the American Board of Nuclear Medicine.
The chief way to protect against the harmful effects of fallout is to remain indoors and refrain from eating leafy foods that may have become contaminated. If venturing outdoors is necessary, Ross recommended frequent showers with lots of soapy water.