Types of Radioactive Waste at Einstein

Radioactive waste must be segregated by radioisotope and by the type of waste that it is. If a laboratory is working with multiple radionuclides, the laboratory must have separate waste containers for each radionuclide. Only C-14 and H-3 may be placed into the same waste container, all other radioisotopes must be segregated from one another. All containers should be labelled with the “Caution: radioactive material label, the radioisotope, the date, and the total activity.   

Dry Solid Waste: This type of waste consists of contaminated material that is dry such as paper towels, absorbent materials, plastic and glass. Gloves, pipette tips and empty vials are included as well. Before adding waste to a container, be sure that the container is lined with a durable bag to ensure that the container’s interior does not get contaminated.

Liquid Waste: This type of waste consists of aqueous, non-hazardous liquids. Unless the waste is stock solution, the waste should be collected in a durable plastic container with a screw top lid. Liquid waste with other hazardous properties such as flammable, corrosive, toxic, or reactive must be collected as “mixed waste”. 

Aqueous radioactive waste that does not have other hazardous components such as flammable, corrosive, toxic, or reactive properties may be disposed through an authorized sink drain to the sanitary sewer system. There are specific weekly and monthly activity limits which must be followed and a log to be completed when disposing through sink disposal. A copy of the Sink Disposal Log can be printed and kept next to an authorized sink drain. High activity liquid waste may need to be collected and decayed separately to avoid creating a “hot sink” in the laboratory. Small quantities of liquids can be absorbed onto an absorbent pad and be placed into a dry solid waste container for that radioisotope. 

Liquid Scintillation Vials: This type of waste is generated when completing monthly wipe tests for contamination. Laboratories can use plastic or glass vials when counting their wipe tests in a liquid scintillation counter or gamma counter. Before adding vials to a container, be sure that the container is lined with a durable bag to ensure that the container’s interior does not get contaminated. Make sure that the caps to the vials are secured tightly so that the liquid does not leak into the waste container. EH&S recommends using biodegradable scintillation fluid; however, some scintillation fluids can be flammable or corrosive. If flammable or corrosive fluids are used, this must be noted on the pick-up request form in iLab. 

Mixed Waste: This type of waste is radioactive material that contains hazardous properties such as that it is flammable, corrosive, toxic, or reactive. If the waste contains a short-lived radionuclide (half-life < 90 days) it may be decayed for 10-half-lives and then disposed of as chemical waste through EH&S. Due to regulatory restrictions and very high disposal costs, all attempts must be made to minimize the generation of mixed waste.   

Animal Carcasses & Pathological Waste: This type of waste includes animal carcasses, tissue samples, and pathological waste that is used with radioactive material. The waste must be stored frozen in a laboratory freezer and labeled accordingly. If short-lived radioisotopes (half-life < 90 days) were used, the material may be decayed for 10 half-lives and then be disposed of as pathological waste. If long-lived radioisotopes (half-life > 90 days) were used, the waste will need to be stored in a laboratory freezer until the College has their vendor come to do pick-up. If the animal carcass contains H-3 or C-14 in quantities less than 0.05 uCi/gram averaged over the entire mass of the carcass, the carcass may be treated as non-radioactive and may be handed over to the Institute for Animal Studies for pathological waste disposal. If the concentration of H-3 or C-14 is greater than 0.05 uCi/gram, the waste needs to be treated like all other long-lived animal waste above. An animal use protocol must be in place to work with animals and radioactive materials. 

Animal Bedding and Cages: This type of waste is generated when working with radioactive materials in animals. Each animal cage, with bedding inside, must be labeled accordingly and stored within a closed durable plastic bag. Cages and animal bedding contaminated with long-lived radioisotopes (half-life > 90 days) must be disposed of as radioactive pathological waste. Laboratories may clean the cages with a radioactive decontaminant cleaner (such as NoCount Solution) and wipe test the cages thoroughly to confirm that there is no contamination. If there is no contamination, the cages may be returned to the Institute for Animal Studies after being surveyed by the Radiation Safety Officer. Disposable cages may be purchased for use with long-lived radioisotopes. Contact the Radiation Safety Officer and the Animal Institute for more information on disposable cages. 

As with animal carcasses and tissues, bedding and cages used with short-lived radioisotopes (half-life < 90 days) may be held for decay for 10 half-lives. Decayed animal bedding may be disposed of as non-radioactive pathological waste. Decayed cages shall be returned to the Animal Institute.    

Radioactive Sharps: This type of waste consists of syringes, needles, razor blades, etc. that have been used with radioactive material. These items must be placed into a sharps container that is labelled with a “Caution: radioactive material” label. Just as all other radioactive waste streams, the waste must be segregated by radioisotope. If a long-lived radioisotope (half-life > 90 days) is used, the waste will need to be disposed of as dry waste. If a short-lived radioisotope (half-life < 90 days) is used, the waste may be decayed for 10 half-lives. Decayed sharps will be handled the same way as other decayed waste (see below). 

Decayed Waste: This type of waste is no longer radioactive. The original radioactive material must be decayed for at least 10 half-lives to be disposed of as decayed waste. Only radioisotopes with a half-life of < 90 days may be held for decay. All radioisotopes with a half-life of > 90 days must be disposed of through a radioactive waste vendor (aside from sink disposal). Laboratories must complete and file a “Survey Record of Disposed Radioactive Waste from Decay-In-Storage Form” after the waste has decayed for 10 half-lives.