Biological effects of low levels of radiation exposure

Some general perspective is provided concerning the orders of radiation dose equivalent levels associated with exposure of human populations to ionizing radiations from consumer products. This is followed by considerations of the biological effects and risks of low levels of radiation exposure. Some consumer products emit low-LET (i.e., low linear energy transfer) radiations beyond their confines and these penetrating radiations can result virtually in whole-body irradiation, while in the case of other products the radiation to tissue consists mainly of the high-LET alpha particles which penetrate tissue only shallowly and close to the products. There are some radiation-emitting consumer products which are in such widespread use in the United States that large numbers of people are irradiated by them. Some of these products may irradiate on the order of 106 to 108 people to average annual whole-body or gonadal dose equivalents varying over a range on the order of 1 to 10 millirem (mrem). These include television receivers, time pieces with radium-containing dials, gas and aerosol detectors, and building and road construction materials. On the order of 104 people may be irradiated by vacuum high voltage switches to 30 mrem or from electron microscopes to 300 mrem average annual whole-body or gonadal dose equivalent. Smaller annual whole-body or gonadal dose equivalents, of the order of less than 1 microrem (μrem) to 1 mrem, may be received by many people from cold cathode gas discharge tubes, airport x-ray inspection systems, time pieces with dials containing tritium or 147Pm, and other sources. Possible health hazards are discussed