Radiation Hazards of Primary Concern to Public Health-Present Status and Outlook.

The radiation hazards currently of primary concern to public health are fallout of radioiodine from testing nuclear weapons and excessive x-ray exposures performed by careless and sometimes poorly trained physicians. Because of the relatively short half life of I/sup 131/(8 days), it might be expected to be of little consequence as a public health hazard following nuclear weapons testing. However, the yield of I/sup 131/ from a nuclear weapon is sufficiently high that considerable contamination of the environment takes place, and the hazard to the general population becomes greatest when the weapon is detonated at low altitude. The ground contamination problem increases as the altitude of detonation decreases. After the USSR tests of 1961, levels of I/sup 131/ contamination rose rapidly-in a few communities to a level which, if continued over a period of several months, would cause a dose in excess of the Federal Radiation Council's (FRC) radiation protection guide of 0.5 rem. The meteorologic aspect is of interest to public health authorities because it clearly indicates the manner in which variation in the weather pattern may cause fallout to occur from time to time in quite unexpected places. As a result of later detonations, estimates indicate that inmore » some regions of the United States the radiation dose received by the thyroid glands of children may reach a level of 1.5 rem/yr, which represents the ingestion of 100,000 mu mu C of radioiodine. This amount is 3 times the quantity of radioiodine recommended by the FRC as a maximum limit. The FRC has announced that its radiation standards, applicable to the peacetime uses of radionuclides, do not apply to environmental contamination from fallout. The political implications of this decision, as well as the confusion it has introduced among public health authorities, are discussed. Reduction of the I/ sup 131/ hazard by the use of dried or stored fresh milk by infants and lactating mothers, and addition of stable iodide to the diet, are also discussed. Problems of medical overexposure to radiation are, in general, the result of the use of unsafe x-ray equipment or careless use of x-ray equipment. It is recommended that exposure dose values to such tissues as the reproductive organs be reduced to 15 mr/yr or about 15% of the exposure dose from natural background sources, as an The duties and experiences encountered during the 4-yr operation of a radiation control agency are recounted. The most important part of a comprehensive radiation control program, in terms of overall exposure of the population, is the effort to minimize the radiatlon exposure from the medical and dental use of x-rays. The fact that much of the equipment is installed in apartmert houses, other multiple dwelling structures, and office buildings means that a more critical evaluation of the structural shielding is necessary. An inspection of existing x-ray installations showed that much equipment had been installed in multiple dwellings without having the basic structural shielding considered standard practice for many years. Public health considerations relating to siting nuclear reactors in cities are discussed, particularly with respect to nuclear-powered vessels entening the harbors of large cities. The problem of safeguarding the public from hazards associated with the transportation of radioactive materials in a large city is also discussed. Dosimetry tests showed that many watches being sold with luminous dials exceeded permisnible dose rates, and many jewelry and department stores have been restrained from selling such watches. Other tests showed that, under normal use, television equipment does not emit a sufficiently hlgh dose rate of x-rays to constitute a health hazard. (BBB)« less