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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 14 C 6 147N + 0 -1 (beta decay) comparing ratios of 14C: 12C – figure how many half-lives gone by since died – helps determine age of substance ROCKS U-238 decays to Pb-206 (manysteps) over time: amount U & amount Pb - scientists compare ratio of U-238 to Pb-206 to date rocks Chemical Tracers detect radioactive materials & decay products tracer: 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 & figures out reaction mechanisms Industrial Applications tracers kill bacteria and spores in food and mail Medical Applications Co-60 & Cs-137: destroys anthrax bacilli Co-60: kills bacteria in foods Tc-99: treatment of brain cancer Medical Applications radioisotopes with short half-lives (quickly eliminated from body) – medical use diagnose & treat cancers I-131: diagnosis & treat thyroid disorders Co-60: gamma emitter – used to kill cancerous tumors Nuclear Power Plants radioactivity used as fuel source to generate electricity – advantages: no contributions to greenhouse gases no mercury contamination of atmosphere Radiation Risks damage normal tissue high doses can cause illness & death cause DNA mutations disposal of waste is difficult especially from nuclear power plants fuel rods are mix of many radioactive substances storage & transportation both problematic