Usually the highest activity is handled when the isotope stock bottle is opened. If the material is such that there is a possible build-up during shipment or storage, the container should be opened in an appropriate containment. A fume hood is a good site for opening packages. Always assume the outside of the primary container is contaminated and handle accordingly.

########## Direct manipulations

Much of the inadvertent contamination of laboratory surfaces is caused by contact with contaminated work gloves. Nearly all isotope work will involve some direct handling of open isotope containers. Whenever this occurs, assume the gloves are contaminated. Change them immediately if a 'clean' item is to be handled. Never wear the gloves away from the immediate work area after direct handling, and check them frequently with a survey meter (except for H-3). A dry run will show when gloves should be changed and preliminary assembly of all equipment will cut down on movement away from the work area to open drawers, refrigerators, etc.

########## Remote Manipulators

For isotopes presenting an exposure hazard some remote manipulation may be necessary. Use of tongs, forceps, pliers, etc., will lower radiation dose to the hands and reduce contamination spread. Metal implements should be rubber tipped for a more secure grip. Tools are likely to become contaminated and should be checked and cleaned after each use. Any equipment used should be properly labeled.

########## Transfers

When making liquid transfers do the work in a restricted area of the bench so as to avoid personnel and floor contamination from drips, spills, or splattering. For larger volumes of radioactive solution, a tray or tub should be used so all the liquid can be contained in case of spills. Use aids such as automatic pipettes and funnels. Cap solutions that are not to be used immediately. Do not pipette radioactive material with any mouth-operated procedure. When moving an isotope solution away from the bench, secondary containment is necessary. Rigid, covered unbreakable carriers are needed if isotopes are to be transferred through public use areas (such as hallways).

########## SELF MONITORING

When working with isotopes other than H-3, it may be necessary to have a portable survey instrument on hand to monitor exposure levels and check for contamination. A thin-window Geiger-type survey meter is appropriate for work with beta emitters (including C-14 and S-35) and gamma emitters. I-125 monitoring requires use of an I-125 specific scintillation-type detector. The RUA may specify required self-monitoring and documentation requirements. Monitoring with Survey Meters - With the exception of tritium, virtually all beta and gamma emitters can be 'seen' with a GMdetector survey instrument. This instrument can be used to determine the rough location and gross nature of contamination. The appropriate method is to position the probe surface 1 to 2 cm above the suspected surface and then slowly 'paint' the area, listening to variation in the click rate. In general, to check for equipment of personnel contamination, the meter should be shielded from high background. Bench or floor surfaces should be checked directly and by wiping, then monitoring the wipe. Wipe monitoring - This method can be used with all radioisotopes, and is the only reliable method for quantitative determination of contamination levels. Contamination levels are normally expressed as cpm/100 sq. cm of surface. The method involves wiping the surface with an absorbent medium (paper