Radioactive Waste - University of Houston
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Radioactive Waste

Radioactive materials possessed under sublicense, naturally occurring radioactive material, technologically enhanced radioactive material, and uranium and thorium salts are regulated for possession and disposal at the University.

PIs are responsible for implementing effective radioactive waste management procedures in the labs. They must provide adequate radioactive material labeled receptacles for each radioisotope and type of radioactive waste generated. Use a radioisotope disposal form to document this every time.

Radioactive waste should not be stockpiled in the lab. A radioactive waste area should be located away from heavy traffic or high use areas. Adequate space for shielding should be considered. High energy beta and gamma emitters must be stored behind appropriate shielding material to minimize the external exposure to lab personnel. Plan to contain liquid waste in the event of a spill or failure of the plastic carboy. Containment can be easily achieved by placing the carboy or liquid waste container in a secondary container or by placing plastic backed absorbent paper beneath them.

Do not, under any circumstances, place radioactive waste where it might be picked up by housekeeping personnel and be disposed of as ordinary waste in the dumpsters. Accidental and improper radioactive waste pick-up and/or disposal must be reported immediately to the RSO.

Waste Segregation and Minimization

Waste segregation by form and isotope is an effort to minimize the volume of radioactive waste disposed at licensed land disposal facilities. For this initiative to succeed, it is necessary that all PIs and laboratory personnel follow proper radioactive waste procedures as much as possible.

Radioactive waste must be segregated by radioisotope and physical form. The only exceptions are the radioisotopes H-3 and C-14 which can be stored together. Any other exception must be pre-approved by the RSO. The basic physical forms are: solids, glass, sharps, liquid, liquid scintillation vials (LSV), biological, animal remains, source vials, lead pigs, and sealed sources.

Solid


Solid radioactive waste is comprised mostly of solid disposable items that have been contaminated with radioactive material including absorbent work surface coverings, gloves, tubing, etc. This waste is disposed in yellow radioactive material bags supplied by EHS. The use of any other type of plastic bag to collect the solid radioactive waste in the laboratory is prohibited. The yellow radioactive material bags must be placed in waste receptacles that remain closed at all times. Deface or remove all radioactive labels before placing waste into the bags. Do not place anything in the bags in such a way that they may tear it. Inspect the plastic waste bag for leaks prior to removal from the lab. Use a second yellow bag to contain the waste if necessary. Do not mix liquid scintillation vials, lead pigs, and stock vials with the solid waste, especially sharps. Plastic source vial containers, but not the lead impregnated type, may be disposed in the solid waste after being defaced of all radioactive labels. Every bag must be securely sealed and have a completed Radioactive Waste Disposal Form attached prior to pickup.

Glass


Radioactive contaminated glassware and other unbroken glass must be packaged separately from other solid radioactive waste. A strong cardboard box is adequate for disposal use. Every box must be labeled, securely sealed with a completed Radioactive Waste Disposal Form attached prior to pickup.

Sharps


Sharps are defined as anything that could tear the yellow radioactive material bag including needles, razor blades, capillary tubes, broken glass etc. This waste type is disposed in clear, puncture resistant plastic tubes supplied by EHS. These tubes are only for the disposal of radioactive contaminated sharps. Do not recap sharps, exercise caution when putting sharps into the container and do not overfill. Make sure that all sharps are dry before placing into a container. When full, securely cap the tube and have a completed Radioactive Waste Disposal Form attached prior to pickup.

Liquid


Radioactive liquid waste can be further divided into aqueous, acids and bases, and pump oils. Aqueous liquids are water-based liquids with a pH between 5.0-9.0, such as saline and buffer solutions or washings from radioactive contaminated laboratory glassware, and weak acids and bases that contain no biological, pathogenic, or infectious materials. Liquid waste is disposed in 5-gallon plastic containers called carboys, supplied by EHLS. These carboys are not to be filled more than 4/5th full to prevent spills or overflows. No radioactive liquid is to be poured down the sink. Sinks should be checked during routine lab surveys and wipe tests. Pipettes and other such items must not be placed in the carboys. All biological material in the carboys must be properly deactivated using 10 percent bleach solution. Do not mix liquid waste types in the carboys.

Double containment in a tray or pan to adequately contain the liquid is recommended as a precaution against leakage or a spill. This shall also control accidental overflow and drips due to pouring. At a minimum, plastic backed absorbent paper shall be placed under all liquid waste containers. Carboys should be kept as free of contamination as possible. Glass containers, such as used bottles of chemicals must never be used for storage of radioactive liquid waste unless the carboy provided is incompatible with contaminated acids or bases. These, whenever used, must be double contained. Every carboy must have a completed Radioactive Waste Disposal Form attached prior to pickup.

Liquid Scintillation Vials

Liquid Scintillation Vials are glass or plastic vials containing organic or aqueous based liquid scintillation fluid. This waste is disposed in the original cardboard trays and placed in a yellow radioactive material bag or double bagged in yellow radioactive material bags. Glass vials not in the original trays must be double bagged in yellow radioactive material bags. Ensure that all vial tops are closed tightly because all scintillation fluids could dissolve plastic over time. Every bag or box of vials must be securely sealed with a completed Radioactive Waste Disposal Form attached prior to pickup. The use of biodegradable scintillation fluid is strongly recommended.

Biological


This category covers liquid radioactive waste containing biological, pathogenic, or infectious material including by-products of animal waste, labeled culture media, etc. This waste is disposed either in yellow radioactive material bags and labeled with biological waste stickers, or in red biological bags labeled with radioactive material stickers. Both types of bags are supplied by EHLS. Liquids must be absorbed into some absorbent material such as paper towels, sponges, gauze, etc. prior to placing into bags. Pathogenic and infectious waste must be sterilized by chemical treatment. Do not autoclave radioactive contaminated biological waste except where the autoclave is dedicated for such waste only. Every waste bag must be securely sealed with a completed Radioactive Waste Disposal Form attached prior to pickup.

Animal Remains

This category covers radioactive animal carcasses and by-product waste including viscera, serum, blood, excreta, tissue, etc. to be incinerated. Animal remains containing radioactive material are subject to handling according to the guidelines stated in the Radiation Safety Procedures for the Use of Radioactive Material in Animals. This waste is disposed in yellow radioactive material bags supplied by EHLS. Every bag must be securely sealed with a tag indicating the date, radioisotope, total activity, and the PI tied to the bag. Liquids must be absorbed into some absorbent material such as paper towels, sponges, gauze, etc. prior to placing into bags.

Source Vials

These are the original vials that the radioactive material was shipped in to a lab and includes full, partially full, and empty vials awaiting disposal. All source vials must be returned to EHLS for proper disposal according to licensee’s operational conditions. Source vials are handled differently from the solid waste. Segregation of vials by radioisotope does not apply to source vials. A Radioactive Waste Disposal Form is not required, but the Radioisotope Tracking Form shall be returned along with the source vial.

Lead Pigs

These are the original lead and/or lead impregnated shielded containers of source vials. Lead is a hazardous waste and must be picked up for recycling or proper disposal by EHLS. Lead pigs and lead impregnated shielding containers must be kept separate from the solid waste. A Radioactive Waste Disposal Form is not required. Segregation by radioisotope does not apply to lead pigs. Manage lead pigs as unwanted material in laboratories or as hazardous waste if generated outside of laboratories unless otherwise instructed by EHS.

Sealed Sources

Sealed sources include calibration sources, check sources, quenched standard sets, electron capture gas chromatograph detectors, etc. Final survey and/or leak tests are required to be performed on all sealed sources prior to disposal. All sealed sources must be turned in to EHLS for proper disposal even if it is deemed decayed. PIs and AUs must check for broken or crushed sources and handle these damaged sources with extreme care. Notify the RSO immediately if a source breach or contamination is found or suspected. Sealed sources must be kept separate from the other wastes for disposal. A Radioactive Waste Disposal Form is not required. Segregation by radioisotope does not apply to sealed sources.