Re: Pb-210 contamination

[Ninni Jacob <njacob@gsosun1.gso.uri.edu>]

I have some contamination from the decay products of Ra-226(which is the
same as the decay products from uranium) which had been placed in a cabinet
for 30 years. 
The source was removed and the cabinet decontaminated as much as possible.
 But there is still some residual activity.
The activity, I believe, is coming from Pb-210 which is the final decay
product.

If you look up the acceptable surface contamination levels, it is not
clear whether I should treat this as Pb-210 or the decay products of
uranium, because the limits are different.

In the Rad Health Handbook (1992 Edition), Table 11.1.5  and Table 11.1.6
(pages 406 and 407) lists 20 dpm removable, and 100 dpm(fixed plus removable)
for Pb-210,  whereas the limits are 1000 dpm(alpha) removable for uranium and
associated decay products.

My smears indicate there is about 50dpm(alpha) and 75dpm(beta) maximam.
The geiger counter reads 500 cpm max.
So I am wondering whether I  can release the cabinet for unrestricted use.
There are also some contaminated items in the cabinet.  What di I do with
those?   How Do I dispose of them?

 Any ideas will be appreciated.