Cardiovascular mortality in relation to radioactivity and hardness of local water supplies in the USA.

Several authors have reported an inverse correlation between death rates from cardiovascular diseases and local water hardness, but the significance of such a relationship is still debated. To investigate further this relationship, another indicator of water quality was used, namely, the alpha-radioactivity level of raw river waters in the USA. This indicator also showed a negative correlation with cardiovascular death rates, particularly from hypertensive heart disease, which was consistent whether the data were analysed by state, by river basin, by county, or by community. The fact that the negative relationship holds true for raw river waters indicates that broader environmental and geochemical factors may be involved. The effects of trace elements present in the soil and in the water on man's mineral balance, and eventually on the cardiocirculatory function, are discussed.