Benefits & Dangers of: Radioisotopes

Dating (not that kind) C-14 used to date organic (previously living) materials Living organisms incorporate C-14 into their structure, along with C-12 C-14 decays with known half-life 14C  14N + 0 comparing amounts of C-14 & C-12 can figure how many half-lives have gone by since it died Helps determine age of substance 6 7 -1

ROCKS U-238 decays to Pb-206 (many steps) Over time, amount of U  and amount of Pb  Scientists use the ratio of U-238 to Pb-206 to date rocks

Chemical Tracers Able to detect radioactive materials and their decay products Tracer = any radioisotope used to follow path of material in system P-31: determines P uptake in plants C-14: maps C in metabolic processes C-14: maps organic molecules and figures out reaction mechanisms

Industrial Applications Kill bacteria and spores in food and mail

Medical radioisotopes with short half-lives (quickly eliminated from the body) Tracers in medical diagnosis Treatment of cancer I-131: Diagnosis & treat thyroid disorders Co-60: gamma emitter Used to kill cancerous tumors

Medical Co-60 and Cs-137: destroys anthrax bacilli Co-60: kills bacteria in foods Tc-99: treatment of brain cancer

Power Plants Used as a fuel source to generate electricity No contributions to greenhouse gases No mercury contamination of atmosphere

Radiation Risks Can damage normal tissue High doses can cause illness & death Can cause mutations in DNA Disposal of waste is difficult (esp. from nuclear power plants) Fuel rods are mix of many substances Storage & transportation both problematic