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Prudent Practices in the Laboratory: Handling and Disposal of Chemicals
from biomedical research using radioactive materials with infectious agents, blood, and body fluids. On-site incineration, autoclaving, and off-site disposal are the management options for this waste. Chemical decontamination (e.g., soaking in bleach) may be appropriate if it can be done without risking personal exposure, increasing waste volumes, or creating a waste that is difficult to handle (e.g., wet waste). After disinfection, radioactive-biological waste can be managed as radioactive waste.
Infectious waste and needle boxes that contain radionuclides can be autoclaved safely if the following precautions are satisfied:
Monitor the air emissions of a test load to determine if the release of radioactive material is in compliance with U.S. NRC and license limits.
Wipe-test the autoclave interior for surface contamination regularly.
For ongoing treatment of this waste, dedicate an autoclave or autoclave room for this purpose. The room should have ample ventilation.
Restrict access during autoclaving.
Test the autoclave efficacy regularly.
Radioactive needles contaminated with infectious agents or blood should be autoclaved as described above, and then incinerated on site or shipped to a low-level radioactive waste site. To prevent injuries, it is important that hypodermic needles and other sharps be kept in waste containers that are puncture-resistant, leak-proof, and closable from the point of discard through ultimate disposal. To prevent airborne radioactive materials, destruction of needles by grinding or a similar means is not recommended.
7.C.3.5 Sewer Disposal of Radioactive-Biological Liquids
Radioactive blood, body fluids, and other sewer-compatible liquids may be disposed of in the sanitary sewer if quantities are within U.S. NRC license and treatment works limits. Precautions must be taken to prevent exposure of waste handlers. OSHA recommends that disposal of human blood and body fluids be done in a dedicated sink.
Chemical-radioactive-biological laboratory waste (depicted in Figure 7.2.d) is the most difficult multihazardous waste to manage. The strategies for managing the various other types of multihazardous waste described above are generally applicable to chemical-radioactive-biological waste. For example, toxicological research sometimes generates animal tissue that contains a radioactively labeled toxic chemical. However, the chemical toxicity of such waste is commonly inconsequential, both legally and in relation to the waste's other characteristics. It could be appropriate to dispose of such animal tissue as a radioactive-biological waste, without regard to its low toxic chemical content.
Reduction or elimination of one of the waste hazards through waste management methods is often an efficient first step. Decay-in-storage is a simple, low-cost way to reduce the radioactivity hazard of a waste with short-lived radionuclides. After decay, most U.S. NRC licenses allow the waste to be managed as a chemical-biological waste. Similarly, autoclaves are readily available to most laboratories for destruction of infectious agents. As described above, autoclaving multihazardous waste requires certain precautions, but renders a chemical-radioactive-biological waste a chemical-radioactive waste. Autoclaving or disinfection makes sense when any of the waste's characteristics (e.g., nutrient value) could support the growth of an infectious agent it contains and thus could increase the waste's risk.
Certain waste treatments reduce multiple hazards in one step. For example, incineration can destroy oxidizable organic chemicals and infectious agents, waste feed rates can be controlled to meet emission limits for volatile radionuclides, and radioactive ash can be disposed of as a dry radioactive waste. Likewise, some chemical treatment methods (e.g., those using bleach) both oxidize toxic chemicals and disinfect biological hazards. Such treatment could convert a chemical-radioactive-biological waste to a radioactive waste.
7.C.5Future Trends in Management of Multihazardous Waste
Multihazardous waste is becoming the focus of much attention by regulatory agencies, as well as by the laboratories that must deal with it. The U.S. NRC relieved much of the laboratory mixed waste problem by allowing liquid scintillation fluid (LSF) with less than 1.85 kBq/g of 3H or 14C to be disposed of without regard to radioactivity. Thus ignitable LSF below this limit need not be managed as a mixed waste but only as a hazardous chemical waste. As explained above, although U.S. NRC policy has not established a de minimis level for other types of laboratory radioactive waste, licensees can often propose a license-specific de minimis level, below which mixed waste can be released for management as a chemical waste.
Regional EPA offices and state and local hazardous waste authorities differ in their regulation of storage