Radionuclide Fact Sheet 
PHOSPHORUS - 32
Symbol: 32P
States/Forms: Soluble
Physical Characteristics
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Radioactive Half Life (T½): 14.3 days
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Decay Type: Beta- (ß-)
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Maximum Energy Emission: 1.71 MeV
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Maximum Range in Air: 611 cm
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Maximum Range in Water/Tissue: 0.76 cm
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Maximum Range in Plexiglas or Lucite: 0.61 cm
Hazard Category
- A Level (High Hazard): >100 mCi
- B Level (Moderate Hazard): >2 mCi to 100 mCi
- C Level (Low Hazard): 0.01 mCi to 2 mCi
Radiological Characteristics
- 95% of beta particle energy transmitted through dead layer of skin.
- Critical organs: Body tissues – 70%; Bone – 30%
- Routes of intake: Ingestion, inhalation, puncture, wound, skin contamination (absorption).
- Internal exposure and contamination: Primary radiological concerns with 32P
- External exposure: Primary radiological concern with 32P.
Dosimetry
- Film badges and dosimeter rings are required if 1 millicurie (mCi) or more is to be handled at a given time, or if millicurie levels are handled frequently.
Bioassay Requirements
- Urinalysis may be required after spills or incidents of contamination.
External Radiation Hazards and Shielding
- Assuming there is no backscatter or self-absorption, the dose rate at 10 cm is 2.7 rads/hour from an unshielded 1 mCi dried sample of 32P. If the skin is contaminated with 32P, 1 microcurie/cm2 (μCi/cm2) will deliver a dose of 9200 miilirads per hour (mrad/hr) to the basal cells of the epidermis. Lead foil or sheets, or other high density materials should NEVER be used to shield 32P directly due to the production of penetrating Bremsstrahlung x-rays. Lead materials can be used as shielding from Bremsstrahlung x-rays ONLY if behind low-density plexiglass, acrylic, lucite, or wood shielding.
Hazards if Internally Deposited
ALI (Annual Limit of Intake):
- 600 μCi – by ingestion (all compounds)
- 900 μCi – by inhalation (except phosphates)
- 400 μCi – by inhalation (phosphates)
DAC (Derived Air Concentration):
- 2 x 10-5 μCi/mL
Survey Instrumentation
- A Geiger-Muller survey detector with a pancake/frisker probe can be used to detect 32P. The counting efficiency for 32P is approximately 25%.
- A low-energy NaI probe can only be used to detect Bremsstrahlung x-rays.
- Liquid scintillation counters should be used to detect removable surface 32P contamination using smears or swabs.
Problems and Precautions
- Phosphorus-32 is commonly the highest energy radionuclide encountered in a research setting, and thus requires special caution. Exposure should be avoided and handling should be limited as much as possible.
- Always wear a lab coat, disposable gloves, and safety goggles when working with 32P.
- Bremsstrahlung x-ray production must be avoided by working behind low Z shielding, preferably transparent materials.
- Surveys should be conducted frequently and gloves should be changed often.
- Waste should be segregated to those with half-lives of less than 19 days.