Before concern developed over environmental exposure, attention was devoted primarily to exposure in the workplace, where the potential exists for the accidental uptake of radium at levels known to be harmful to a significant fraction of exposed individuals. The purpose of this chapter is to review the information on cancer induced by these three isotopes in humans and estimate the risks associated with their internal deposition.Īll members of the world's population are presumably at risk, because each absorbs radium from food and water as a working hypothesis, radiation is assumed to be carcinogenic even at the lowest dose levels, although there is no unequivocal evidence to support this hypothesis. Later, similar effects were also found to be associated with internal exposure to 224Ra. These studies were motivated by the discovery of cancer and other debilitating effects associated with internal exposure to 226Ra and 228Ra. The primary sources of information on the health effects and dosimetry of radium isotopes come from extensive studies of 224Ra, 226Ra, and 228Ra in humans and experimental animals. It has also been used for internal radiation therapy.
Radium has been used commercially in luminous paints for watch and instrument dials and for other luminized objects. In communities where wells are used, drinking water can be an important source of ingested radium. Radium is present in soil, minerals, foodstuffs, groundwater, and many common materials, including many used in construction. Four isotopes of radium occur naturally and several more are man-made or are decay products of man-made isotopes.
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