Sulfur 35

Half-life

87.44 days

Emitter

Beta

Beta Energy

167 keV

Travel distance

  • Air: 10.2 inches or 26  cm
  • Water/Tissue: 0.015 inches or 0.32 mm
  • Plastic: 0.010 inches or 0.25 mm

Annual Intake Limit

  • Inhalation: 6000 µCi
  • Ingestion: 2000 µCi

Detection

  • Portable Survey Meters:
    • Geiger-Mueller [~10% efficiency];
    • Beta Scintillator [~5% efficiency]
  • Wipe Test: Liquid Scintillation Counting is the best readily available method for counting 35S wipe tests

Shielding

None required – mCi quantities not an external radiation hazard

Dosimeter Monitoring

  • Urine bioassay is the only readily available method to assess intake [for tritium, no intake = no dose].

Precautions

  • Avoid skin contamination [absorption], ingestion, inhalation, & injection [all routes of intake].
  • Many 35S compounds and metabolites are slightly volatile and may create contamination problems if not sealed or otherwise controlled. This occurs particularly when 35S amino acids are thawed, and when they are added to cell culture media and incubated. Therefore vent thawing 35S vials in a hood. Incubators used with 35S will have an activated charcoal trap placed in the incubator. Possiblity of volatilization must be taken into account when surveying after use.

Recommendations

  • Please refer MSDS for volatile nature of 35S compounds
  • Take wipes of work areas and equipment surfaces and count them in a Liquid Scintillation Counter
  • Segregate 35S waste and keep separate from 32P, 125I, and other radioactive waste (with the exception of dual label experiments)
  • Consolidate and store the waste in an isolated spot away from work and high traffic areas.
  • Dispose the waste as per USC radiation waste policies. Do not mix the waste with any other isotope.

Radiological Data

  • Radiotoxicity:
    • 2.48 mrem/uCi [CEDE] of 35S inhaled
    • 0.733 mrem/uCi of 35S ingested
  • Critical Organ:
    • Testis
  • Exposure Routes:
    • Ingestion, inhalation, puncture, wound, skin contamination absorption
  • Radiological Hazard:
    • External Exposure – None from weak 35S beta
    • Internal Exposure & Contamination – Primary concern