THE QUESTIONS OF HEALTH HAZARDS FROM THE INHALATION OF INSOLUBLE URANIUM AND THORIUM OXIDES
The insoluble compounds of uranium and thorium, particularly the oxides, are important in the development of atomic energy. Thc questions of health hazards from exposures to dusts of these insoluble compounds are strikily simlar in many but not all respects, Among the similarities may be listed the following facts: The insoluble compounds present no chemical hazard. Both uranium and thorium dioxides, for example, are remarkably inert physiologically. No radiation injuries have so far been described in the lungs of experimental animals inhaling dust concentrations many times the recommended MAC. The lungs of a few dogs studied seven years after excessive inhalation exposures to ThO/sub 2/ gave negative histological findings although high concentrations of thorium were present. The MACs for insoluble uranium and for inxoluble thorium dusts are identical, specifically 3 x 10/sup -11/ c/1. Calculated on a radiation basis, a lower MAC is appropriate for thorium. Based on a considerable body of information from cted. For both uranium and thorium dioxides fecal excretion reflects the immediate exposure to dusty atmospheres. Urine analyses are a prime index of uranium exposure whereas the presence of the much less soluble thorium dioxide in the lung cannot be thus assessed. Breath thoron extimnations or possibly measurements using a whole body counter have been recommended as indices of thorium exposure. The fundamental question depends on the radiosensitivity of the lung and of the pulmonary lymph nodes; neither the production of radiation injury nor the production of cancer are evaluated at present with respect to dosage of radiation. The lung tissues of the dogs described above must have received several thousand rem during the 7 year period. The pulmonary lymph modes must have received considerably more radiation because the concentrations in these nodes e use of the insoluble oxides and the low MACs combine to raise recurring questions of health hazards. (auth)
- Research Organization:
- Rochester, N.Y. Univ. School of Medicine and Dentistry
- NSA Number:
- NSA-12-014520
- OSTI ID:
- 4318603
- Report Number(s):
- A/CONF.15/P/739
- Resource Relation:
- Other Information: Prepared for the Second U.N. International Conference on the Peaceful Uses of Atomic Energy, 1958. Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ANIMALS- CHEMICALS- CONFERENCE- CYTOLOGY- DUSTS- LUNGS- MAN- MATHEMATICS- PERSONNEL- PHYSIOLOGY- POWER PLANTS- QUANTITY RATIO- RADIATION DOSES- RADIATION INJURIES- SAFETY- SOLUBILITY- STANDARDS- THORIUM OXIDES- TOXICITY- URANIUM OXIDES
BODY- CARCINOGENESIS- COUNTERS- DISTRIBUTION- DOGS- DUSTS- INTESTINE- LUNGS- LYMPH SYSTEM- MEASURED VALUES- METABOLISM- RADIATION DOSES- RADIATION INJURIES- RADIOSENSITIVITY- RADON 220- - SAFETY- SOLUBILITY- THORIUM OXIDES- URANIUM OXIDES- URINE- USES