STANDARD OPERATING PROCEDURES
Carbon-14
version: September 26, 1991
INTRODUCTION
Carbon-14 is a commonly used radionuclide with a half-life of
5,730 years, emitting only beta particles with a maximum energy
of 0.156 MeV (Million Electron Volts) and an average energy of
0.049 MeV. The beta particles from C-14 travel a maximum of 22 cm.
CONCERNS
The major concern with using C-14 is that it cannot be easily
monitored during it's use, therefore, special precautions are
needed to keep the work environment clean. The regular use of
wipe testing is the only way to insure that your work space is
not contaminated. Contamination on the skin will not likely cause
a significant dose to the dead layer of skin, however, it could
lead to the internal absorption of C-14. The maximum permissible
body burden to the whole body is 0.4 millicurie.
SHIELDING
Glass and plastic are the best shields for beta particles from
C-14.
DETECTION
A tiny drop of contamination from C-14 can be easily detected with
a wipe test from a Liquid Scintillation Counter. Most Geiger
Counters will not efficiently detect the presence of C-14.
EQUIPMENT / SUPPLIES
The following equipment and supplies must be available:
- a Liquid Scintillation Detector.
- disposable latex or plastic gloves.
- a full-length lab coat.
- radioactive waste receptacle
- pipettes dedicated to the use of C-14.
- commercial decontaminate, i.e. Dupont's "Count Off".
SAFETY RULES
If the following safety precautions are used, personnel radiation
exposure will be as low as reasonably achievable.
- Designate a specific area of the lab for C-14 handling.
- Full-length lab coats must be worn by all persons who
handle C-14.
- Protect your hands from becoming contaminated from spills
by wearing two pairs of disposable gloves.
- Never pipette C-14 by mouth.
- Only use pipettes which have been dedicated to your
specific use of C-14.
- Pipettes will easily become contaminated and therefore,
should not be shared with others.
- If you have reason to believe that your gloves are
contaminated, immediately dispose of them in the
radioactive waste container
POST-USE PROCEDURES
After handling C-14,
- Conduct a wipe test and count the wipes in a Liquid
Scintillation counter:
- Check all equipment, centrifuges, water baths for
contamination.
- If any contamination is found, use a commercial
radiation contamination remover (i.e. Count Off)
with paper towels to clean up the equipment.
- Place the towels in the radioactive waste receptacle.
- If contamination cannot be removed, place a
"radiation" label on the equipment indicating that it
is C-14, maximum cpm found, and the date you measured
the level.
- Check the work bench and floor.
- If contamination is found, it can usually be removed
easily with "Count Off". If it cannot be removed,
contact the RSO to obtain shielding materials.
- Inform your fellow lab workers if any unremovable
contamination is found.
- Check the normal trash container to make sure no
radioactive waste has been accidentally placed there.
- Store the waste temporarily in containers marked with
labels "Radioactive Waste-Do Not Empty". These labels
are available in the RSO.
- Send a Radiation Contamination Survey
Report to the RSO.
- Call the RSO if you have any questions about where to
survey, or how to fill out the form.
- Wash your hands thoroughly.
- Bring the waste frequently to the RSO. We accept waste
every Friday. Call 656-2570 to make an appointment.
º Any questions about these procedures ?
Call the Radiation Safety Office, 656-2570 º