Transcript good & bad news about radioisotopes

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