Radon-radium water treatment bulbs. The box at left contains bulbs of radon, while the box at right contains bulbs of radium. Both are radioactive isotopes that can cause radiation poisoning, cell mutations, cancer, and (in high doses) death. In the early 20th century, it was thought that radon water was the ultimate health cure. This notion stemmed from the discovery that many of the natural hot springs that were used as health spas were radioactive. These bulbs were designed to be used with a siphon to prepare radioactive soda water (water with carbon dioxide bubbles in it). These bulbs were made by Sparklets Limited, based in London. The directions for use say: insOne tumblerful to be taken twice daily after the principal meals.ins