It is vitally important that you have accurate data concerning the isotopes and activity present in your waste. Safe disposal of radioactive waste is expensive. When designing a laboratory procedure, minimize waste generation and mixed waste streams as much as practicable.
Definition
Radioactive waste includes any items that contain radioactivity that is distinguishable above background levels using an instrument that is sensitive for the nuclide, and that is set on its most sensitive scale, and with no interposed shielding.
Detecting low energy radionuclides
Many radioactive wastes, such as H‐3, C‐14, S‐35, and I‐125 are not readily detectable with GM survey instruments. Hence, items that are in the work area where these or similar unsealed materials are present must be assumed to have been contaminated unless they are surveyed by an acceptable alternative method.
For waste contaminated with low energy beta emitters, make smear surveys and measure them with a liquid scintillation counter. For I‐125, use a NaI(Tl) scintillation detector to survey potentially contaminated items. If this is impractical, our policy is to assume that the surface is contaminated and discard it as radioactive waste.
Decontamination
Dish detergent, window cleaner, vinegar, bubble bath, waterless hand cleaner, or oven cleaner are all suitable for cleaning surface contamination. Use mild products for skin contamination.
Half‐life categories
Separate all radioactive wastes by half‐life so that short half‐life materials can be held for decay followed by incineration rather than disposal by burial.
Radioactive waste containers and log sheets
All waste containers must be labeled with the radiation symbol and a sign reading “Caution—Radioactive Materials.” For each disposal log, note the radionuclide quantity in microcuries, date of disposal, and your initials.
Do not use containers other than those provided by Health Physics To ensure radioactive waste is distinguishable from house waste.
Dry waste boxes
Place only dry, non‐decomposable wastes such as gloves, paper, and glassware in Dry Waste Boxes. Do not put any liquids, capped vials, lead shields, animals, bedding, or scat into the container. Waste that emits more than 2mrem/hr at 30 cm must be shielded. Do not shield individual items in the box; shield the entire container. Also, bag waste contaminated with volatile materials, especially iodine, prior to disposal.
Waste removal
When a container is almost full, fax a copy of the waste log to Health Physics. Be sure the room number and CRA number are on the form. Leave the pink copy of the log on the box. This will serve to identify the correct box during the pick‐up; it can be used as a log for additional disposals prior to pick‐up.
Sharps
Discard sharps, such as pipettes, syringes and needles, broken glass, razor blades, and scalpel blades into sharps containers bearing the radiation warning label and log sheet. Use separate containers for isotopes other than C‐14 and H‐3. For disposal, the full capped sharps container may be placed in a dry waste box containing the same isotope. Enter the contents of the sharps container onto the dry waste log sheet. For separate removal of sharps containers, fax the log sheet to Health Physics.
Large items
Large non‐combustible items such as contaminated equipment should not be placed in a Dry Waste Box. Call Health Physics for assistance in the disposal of such items.
Scintillation Vials
See page 56.
Aqueous waste
Material that is readily soluble in water may be disposed of into the sanitary sewer system with adequate flushing, provided that:
The material is not chemically hazardous or containing biohazardous material of BSL‐ 2 or above, or it is not medical waste other than patient urine or feces. See the following web sites to identify:
https://nonhazardouswaste.stanford.edu
http://med.stanford.edu/school/HS/biosafety/bac.html
Contact the manager of the environmental protection program for guidance (725‐ 7529); and
The quantity per laboratory, per day, does not exceed the QLM quantity. Disposal of larger quantities of radioactive wastes via the sewer must be reviewed and have the written approval of Health Physics; and
Log each disposal of radioactivity to the sanitary sewer with the date, activity, form and your name on the Daily Use Log in the Radioisotope Journal; the properly completed Daily Use Log entries constitute the waste disposal record.
Health Physics will post sinks used for disposal of radioactive wastes with proper warning signs to alert plumbers who service the sinks. Use one sink for disposal of radioactive materials in each laboratory.
Human excreta from nuclear medicine procedures
Human excreta containing radioisotopes may be disposed of in the sanitary sewer system.
Cement kits
If you are generating small volumes of liquid waste that cannot be disposed in the sanitary sewer (see Aqueous waste above), order a cement kit. This method of disposal is required for radionuclides with a QLM value of 1 microcurie or less, except for I‐125 and I‐131 which have sewer limits of 100 microcuries per month per project. Cement cans hold about one liter. Use a different kit for each individual radionuclide.
The instructions for use are provided with the kit. For removal of filled cement kits fax the log sheet to Health Physics.
If using a cement kit for mixed waste training is required. Contact the Manager of Environmental Programs (725‐7529).
Radiological and biohazardous (BSL>2) and/or medical waste
Combined radiological and biohazardous (BSL>2) and/or medical waste materials, other than human excreta, must be deactivated prior to disposal as radioactive waste. The project staff should review the potential methods of disinfecting with Health Physics. The deactivation methods must be described by the project and reviewed and approved by the appropriate committee. Methods include autoclaving or treating with chemicals such as formalin, carbolic acid, or bleach. Note that wastes with I‐125 or I‐131 may be especially difficult to deactivate because heat and strong bleaches may drive off the radioiodine vapors, presenting airborne hazards or contaminating equipment.
Radiological and non‐ biohazardous and/or non‐medical waste
Non‐biohazardous biological (BSL 1) or non‐medical waste combined with radioactive waste must be handled as radioactive waste in accordance with California regulations.
For BSL levels, check the Biosafety data base at:
http://med.stanford.edu/school/HS/biosafety/bac.html
Liquids. Follow guidance for permissible disposal in the sanitary sewer; this requires approval of Health Physics during the CRA review process. Do not autoclave combined non‐biohazardous biological‐radioactive liquid waste. Do not bleach or chemically treat combined non‐biohazardous biological‐radioactive waste to inactivate the biological organisms prior to disposal.
Solids. Dispose of non‐biohazardous biological‐radioactive waste as radioactive waste. Segregate combined biological‐radioactive waste from biological waste that would be red‐bagged.
Sharps. Use only the sharps containers provided by Health Physics. Do not discard combined biological (BSL 1)‐radioactive sharps in a sharps container that does not have the radiation symbol.
For the safety of waste handlers, please specially annotate disposal of wastes that have been treated for pathogens or infectious agents.
Mixed Waste
Mixed waste is defined as waste that contains radioactivity and chemical wastes as defined in EPA and California regulations (corrosive flammable, oxidizer, air/water reactive, toxic). These “mixed” wastes need to be specially identified and handled. Generation of mixed wastes must be approved by the appropriate local control committee before it is generated. See: http://mixedwaste.stanford.edu
Radiological and hazardous chemical waste
California hazardous waste regulations prohibit disposal of chemical materials to the sewer unless they have been shown to be non‐hazardous. EH&S has reviewed many chemical materials such as buffers and salts to determine if sanitary sewer or house waste disposal is allowable. Check the “Non‐hazardous Waste List” at: https://nonhazardouswaste.stanford.edu
Search instructions will help you determine if the chemical is listed and therefore non‐hazardous. Be careful to review the conditions; many materials are non‐ hazardous only below a certain concentration.
If you have a material that is not on the list but you believe it to be non‐hazardous, or if the material can be made non‐hazardous with simple in‐lab treatment, call the Radiological Waste Program. There may be additional applicable data or testing methods. EH&S will make the determination. Treatments must be documented in your Radioisotope Journal.
If the half‐life is less than 15 days, the material may be stored for decay and then treated as chemical waste.
Mixed wastes, with prior approval, like hazardous chemical wastes may be accumulated in the laboratory for a maximum of 9 months. Submit a pick‐up request at 8 months.
Decay‐in‐storage
Decay‐in‐storage is one way to handle waste with short half‐lives. To store radioactivity for decay in the lab, the CRA application must specify the areas used to store wastes, as well as the methods used to monitor decayed wastes. Decay‐in‐ storage in the lab is limited to radionuclides with half‐lives less than 15 days.
Decay‐in‐storage requires that wastes be stored a minimum of 10 half‐lives, then surveyed. The survey must show that the radiation is indistinguishable from background. All radiation warning labels must be removed or obliterated before disposing of waste into house waste, or to chemical waste if it began as a mixed waste. File storage logs and surveys in the Radioisotope Journal.
Scintillation vials
The Radiological Waste program provides 5‐gallon buckets for liquid scintillation vials. The Stanford Hazardous Waste Label must be completed and dated when first placing an item into the bucket. Different solvents may be added to the same bucket, but you must add the name of each solvent to the label. A trade name may be used i.e. Readysafe, Cytoscint, Optiphase. Note that, under California environmental regulations, even “environmentally safe” cocktails cannot be released to the sanitary sewer.
Send or fax (723‐3759) the completed request to Radioactive Waste for pick‐up when the pail is full or 8 months old.
The following radionuclides are approved for use in scintillation vials. H‐3 and C‐14 may be combined in the same bucket.
H‐3, C‐14, Na‐22, P‐32, P‐33, S‐35, Cl‐36, Ca‐45, Cr‐51, Co‐57, Fe‐59, Zn‐65, Ga‐67, Ge‐68, Se‐75, Rb‐86, Cd‐109, In‐111, I‐125, I‐131, and Hg‐203.
If you need to perform liquid scintillation counting for other radionuclides, consult with Health Physics.
Vial Disposal Cost Reduction
Scintillation vials not contaminated with a radioisotope may be managed as chemical waste providing a considerable monetary savings. Please separate the vials containing radioactive contamination from those that do not and dispose of accordingly.
Carcasses, bedding, and scat
Certain freezers have been identified as collection points for carcasses, bedding, and scat. These are located in the Research Animal Facility Room RAF‐061 C and D or for imaging isotopes with half‐lives of less than 3 days at Clark S035. For other areas, call Health Physics at 723‐3201.
If animals have been etherized, let the carcasses air out thoroughly in a fume hood before placing them in the freezers to avoid the risk of fire or explosion from the ether fumes.
Discard contaminated bedding, carcasses, and scat, segregated by the half‐life category, into double plastic bags. In respect of public sensitivities, please use an opaque outer bag. Tag all animal waste on the outside of the bag indicating isotope, activity, date of disposal, and account number to be charged. Tags are available at the freezer. Also, fill in the log sheet on the freezer door.
Note: Always use the log sheets provided with the waste containers.
Charges for radioactive waste at Stanford
Radioactive waste charges are included in laboratory overhead. However, please be careful that you do not needlessly create waste, or mix non‐radioactive waste into the waste stream. Projects that generate extraordinary amounts of waste may be billed extra.
