Recent interest in the dose to man from natural radioactivity has been stimulated by the assumption by many geneticists of a linear relationship between radiation dose and the incidence of genetic mutations. Although this has not been demonstrated at the low dose rates prevailing in nature, the likelihood of such a relationship has led to the suggestion that geographical variations in the frequency of spontaneous mutations may be correlated ultimately with differences in the radiation dose to populations (1). This question has recently been reviewed by Gopal-Ayengar (2).The studies of the dose received by man from naturally occurring ionizing radiations can be divided into that received from external and internal sources. The dose to the germ plasm is primarily due to the external radiation, although one internal source, potassium-40, does deliver a dose to the reproductive organs amounting to about 15 mr/ year (3, 4).
Studies of the radiation dose from external natural sources have been reviewed by Sievert (3), Libby (4), and Lowder (5), and extensive sets of measurements with particular emphasis on dwellings have been reported by Hultqvist (6) in Sweden. Although measurements have been made in this country byHess--(7) and Neher (8), no systematic study of the environmental radiation dose rate over an extensive area of the United States has.been reported previously.During the summer of 1957 our laboratory made measurements in the United States to establish the approximate range of population exposures to cosmic and terrestrial gamma radiation. An effort was made to obtain results which would be representative of the unperturbed natural background, affected as little as possible by the occasional substantial variations in the observed natural radiation levels produced by localized sources (for example, the proximity of granite buildings, brick paving, and fallout).Measurements were made with a 20lit., air-filled, polyethylene-walled ioniza-versity of Wisconsin.
Tests were conducted on a laboratory and semi-plant scale to determine the effect of permitting scrap grossly contaminated with uranium to be used in steel manufacture. It was found that most of the uranium is removed with the slag. Steel made with this scrap would have a uranium constituent so little above that made with uncontaminated scrap as to be hardly significant. The slag itself would not present any hazard in handling or normal use. It is recommended, therefore, that in the future steel with only surface uranium contamination be released through normal scrap channels. Note: All references to uremium in this report sire to natural uremium only.
This progress report reviews stray radiation measurements made at representative accelerator sites by members of the Health and Safety Laboratory. Information is presented on radiation levels encountered, personnel monitoring records, economics of radiation protection, and biological effects of ionizing radiation with relation to accelerator operation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.