Liquid Scintillation Waste

Liquid Scintillation Waste is liquid waste, which usually consists of a xylene or toluene based scintillation fluid. LS waste is divided into two categories based on the radionuclides present and the average activity per gram of media: (1) H-3 and C-14 waste with an average activity of less than 0.05 uCi per gram of media, and (2) all other radionuclide LS waste.

Estimates of activity should be based on calculations from actual vial counting. An average of 0.05 uCi per gram of media amounts to about 250 microcuries per case of standard 20 millimeter vials (500 vials). It is very unlikely that activity concentrations this high are routinely used in normal laboratory procedures. Generators should be prepared to justify, with supporting calculations or printouts, LSV waste activities that exceed 100 microcuries per case of standard vials, or a 5 gallon can of waste.

It is important to have a realistic assessment of activity in these wastes. Most LS waste will be generated in vial form. Special arrangements need to be made with the UNM Radiation Safety Office for LS waste that is not collected in vial form.

Important Items

• Vials containing H-3 and/or C-14 shall be segregated from other radionuclides.
• Make sure vials are securely capped. When possible return vials to their original trays for waste pick-ups. Ideally vials should be kept vertical during collection and storage to avoid leakage.
• If vials are collected in 5 gallon containers make sure vials are securely capped and are kept from breaking when disposed of into 5 gallon container.
• All waste containers must indicate radionuclide, activity, and chemical percentages of waste.