Both human and animal studies have been done to examine the health effects of 226Ra. Although radium has several different isotopes, this document is primarily concerned with 226Ra. Only a few of the available animal studies on the effects of 226Ra are useful in the consideration of the effect of low doses of 226Ra. The limited usefulness of such studies is due to the small number of animals tested, and the single, high or unknown doses used. Those studies which have yielded useful results indicate 226Ra causes bone cancer at least at high doses. While the results of the study were not statistically significant, (equivocal), they did point to the possibility that those using such drinking water do have higher rates of bone cancer than others. The young (under eight years) seem to be particularly susceptible to the effects of 226Ra.