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Appendix B: C-14 Information and Safe Handling Guide


Radioactive half-life 5730 years
Decay mechanism Beta emission
Energy Emax = 0.156 MeV
Contamination monitoring Thin window Geiger Mueller detector, liquid scintillation counter for wipe surveys.
Dosimetry Urinalysis bioassay
Shielding Glass and Plastic

  • C-14 is not easily monitored during its use, and special precautions must be taken to keep the work environment clean.
  • Most Geiger counters will not efficiently detect the presence of C-14 but it is easily detected with a wipe test and liquid scintillation counting.
  • Some C-14 labeled compounds can penetrate gloves and skin. Wearing two pairs of gloves and changing the outer pair every 15 or 20 minutes will reduce the chance of contamination and absorption through the skin.
  • Beta particles from C-14 travel a maximum of 22 cm in the air.
  • C-14 may be difficult to distinguish from S-35. If both nuclides are being used in the same laboratory, establish controls to ensure they are kept separate. If "unknown" contamination is found, treat it as C-14.
  • The maximum permissible body burden to the whole body is 0.4 millicurie.

Safety Rules

  • Designate a specific area of the laboratory for all C-14 experiments.
  • All personnel who handle C-14 must wear full-length laboratory coats.
  • Many C-14 compounds readily penetrate gloves and skin. Wearing two pairs of gloves and changing the outer pair every 15 or 20 minutes will reduce the chance of contamination and absorption through the skin.
  • Pipettes dedicated for the use of C-14 should be used. These pipettes should not be used for other purposes as they are easily contaminated by C-14.

Laboratory Cleanup after Use

  • Conduct wipe tests using the liquid scintillation counter checking all work areas and equipment used. Check the floor at the area where the isotope was used.
  • If any contamination is found, use a commercial radiation contamination remover such as Count Off, with paper towels, to clean the contaminated area.
  • Place the contaminated paper towels in a receptacle labeled as radiation waste.
  • If the contamination cannot be removed, label the area or equipment as radioactive, noting the isotope, the date of contamination, and the maximum dpm found.
  • If any un-removable radiation is found, contact the University Radiation Safety Officer.
  • Check the normal trash container to ensure that no radioactive waste was placed there.
  • Store all radioactive waste in specially marked containers.
  • Send a Radiation Survey report to the University Radiation Safety Officer.