HEALTH PHYSICS AND RADIATION PUOTFX'TION 101 



Laboratory Tools and Glassware. Decontamination of equipment is 

 necessary from the point of view both of health protection and of the 

 ehmination of cross-contamination, which will interfere with the experi- 

 ment. For low-level work it is good practice never to use glassware that 

 has been employed with the relatively high-level activity in the original 

 preparations. The conventional methods of cleaning solution, nitric 

 acid, ammonium citrate, or trisodium phosphate may be used for washing 

 glassware. When experiments are performed in which the counting sam- 

 ples are expected to be low, then special care must be taken to avoid 

 contamination by glassware in any part of the operation. Either new 

 glassware should be used or the vessels should be carefully monitored. 



Various Surfaces. The following is a list of agents that have been 

 found effective for the general decontamination of some common surfaces: 



PAINT. Water, steam, steam with detergent, soapless detergents, com- 

 plexing agents such as oxalates or Versenes, organic solvents, caustics, 

 abrasion (wet sandblasting). 



METAL. Water, detergents, organic solvents, complexing agents, dilute 

 nitric acid or 10 per cent sodium citrate, abrasion (buffers), abrasion (wet 

 sandblasting). 



CONCRETE AND BRICK. Hydrochloric acid (32 per cent), abrasion (vac- 

 uum blasting), mechanical removal, flame cleaning. 



PLASTICS. Ammonium citrate, dilute acids, organic solvents. 



LINOLEUM. Carbon tetrachloride, kerosene, ammonium citrate, dilute 

 mineral acids. 



Waste Disposal. It is important that radioactive materials be dis- 

 posed of in such a way that there will be no hazard to the general public 

 or to sanitation workers or sewage-plant personnel. Consideration must 

 also be given to interference with experimental procedures. For instance, 

 the background count from drainpipes must not interfere with radio- 

 assay measurements. Likewise, experimentally grown plants should 

 have no access to radioactive materials that may have been buried nearby. 

 Reviews of the literature dealing with the problem of disposal of radio- 

 active waste to public sewers are available (45 to 48) . Various subcom- 

 mittees of the National Committee on Radiation Protection are develop- 

 ing recommended practices for waste disposal (6, 9). The following 

 remarks are drawn in major part from these reports and are not to be 

 considered as official. 



Possible routes of disposal are sewage, garbage, incinerators, ground 

 burial, disposal at sea, and return to the Atomic Energy Commission. 

 The primary consideration is that no one should receive an appreciable 

 dose of radiation from exposure to waste material. The convenience and 

 expense of the disposal procedure are secondary but nonetheless impor- 

 tant. The half-life of the isotope and the ease of isotope dilution deter- 



