Liquid Radioactive Waste

Lab sink posted with Radioactive labeling

Liquid Waste

Liquid radioactive waste generated on campus may be disposed of through laboratory sinks if certain regulatory and University conditions are met. 

  • Sink Location
    You must use the pre-approved Radioactive Disposal sink in your lab.  As shown in the photo above, the sink will be clearly labeled with Radioactive labeling.
  • Solubility and pH
    The compounds you dispose of either be readily dispersible biological materials or must be aqueous or readily soluble in water. Refer to the list of Radioactive Compounds Approved for Drain Disposal.  If any of your compounds do not appear on the list, contact EHS for a solubility determination.  The pH of your waste must be 5-9.
  • Limiting Contamination
    Pour close and into the drain and run water for a minute after the disposal.
  • Recording & Reporting Disposals
    Every time you dispose of radioactive waste to the sink, you must record your disposal on the lab's Sink Disposal Log and estimate the amount of radioactivity released (see the Resource sidebar to download the form).  At the end of each calendar year, EHS will request that your lab report the total amount of radioactivity released per isotope for that calendar year.
  • Estimating the Amount of Radioactivity in Your Disposal
    You may consult with members of your own lab to estimate what percentage of the radioactivity is expected to end up in the liquid waste.  You may also contact EHS to collect samples of your liquid waste.  EHS will perform liquid scintillation counting of your samples and will provide you with radioactivity concentrations.  
  • Radioactive Gels
    Radioactive gels should be disposed of in the solid radioactive waste bins and not down the sink. They do not need to go in a secondary container in the solid waste bins.

Drain Disposal 

EHS maintains a list of radioactive compounds approved for drain disposal. Disposal of any material not on this list must be approved in writing by EHS. Questions: 609-258-5294 or ehs@princeton.edu

Compounds Approved for Drain Disposal PDF »

[Updated 2/19]