RE: Microfuge contamination

["George Rawls" <GEORGE@pliny.ehs.ufl.edu>]

We also had a large number of contaminated microcentrifuges on a 
routine basis.  After careful observation of lab procedures and swipe 
surveys at different stages of the procedures, we found that, 
contrary to what we thought, in most cases the fuge tubes were not 
leaking at all, but contamination was being transferred to the 
outside of the tubes during pipetting, handling or snapping the lids 
of the tubes and was then being spun off onto the inside of the fuge.

We began immediately to gently correct the handling techniques and 
also began to train for this situation in our user short course.  
A thorough wipe of tubes with tissue before placing in the fuge 
will stop a large percentage of the contamination events. The result 
has been a dramatic drop in fuge contamination. 
 These contaminations still occur but not to such a large degree...we 
still have the occasional lid which snaps open or a poorly loaded 
fuge which can cause the really large activity spill.  

Also we routinely require dedicated, posted centrifuges for 
radioactive material work.  A thorough swipe survey of unposted, 
supposedly RAM free fuges in the same areas resulted in 60% being 
found to be contaminated with RAM.  Needless to say, we also hammered 
this in training and made the necessary corrections in the 
labs....but we still spot check unposted fuges and will in the future. 







George Rawls
University of Florida
Health Physicist