Uses for Radioactive Isotopes

1. Radioactive Dating Used to date once living organisms Organisms stop taking in this isotope when they die and so the lack of carbon-14 is what is measured Only useful up to 4 half life cycles Uranium—238 is used to date rocks and geologic samples

2. Tracers Some isotopes can be used to tag or follow chemicals through an organism or process Phosphorous—31 is used in plants to trace the uptake of fertilizer by the plant

3. Industry Measurement Irradiation of foods to kill bacteria and to preserve the food (Meats, spices)

4. Medical Applications Need to have short half-lives if used Iodine ---131 is used in detection and treatment of thyroid disorders Cobalt – 60 is a gamma emitter that is used in cancer treatment (radiation treatment) Tc-99 is also used in treatment of cancer to detect the presence of tumors

5. Energy Uranium – 235 and Plutonium – 239 are used in the production of energy in nuclear facilities

6. Radiation Risks Isotopes can damage healthy tissues and cells and cause cancer Nuclear power plants produce wastes that cannot be disposed of and these wastes have long half lives Fear of accidents and possible use as weapons lingers for many people