Biodegradable Scintillation Fluids

[10525kfb@ibm.cl.msu.edu (Kristin Erickson)]

I posted a response to the following question yesterday on SAFETY, and a
responder suggested it might be of interest here, too.  So here's the
question and answer.


Question: 
Biodegradble scintillation fluid, can this product be used to replace
the old fluid in all scintillation counting procedures?  If not, when
do you absoutely need the old toxic stuff?


My Response:
We have checked out many types of these "safe" cocktails, and have decided
against using them at Michigan State University for several reasons.  

First,  many gel up when mixed with water.  That really caused a problem
for us a few years back when disposing in the sanitary sewer.  Some vendors
are working on cocktails that will not do that, however.  

Second, the cost is very much higher.  In addition, researchers must
validate methods again when switching cocktails, and that is often very
time consuming.

Third, the "safe" label is based only on the fact that there are no drain
laws against these cocktails.  There has been no actual human health risk,
epidemiological or environmental risk research done on these.  If anyone
has seen any good articles or work done on these things, I would appreciate
hearing about them.  I tried getting specific information on the "safe"
cocktails from numerous vendors when we seriously considered switching
wholesale on our campus, and got nothing but MSDS's, which mostly listed
trade ingredients, and were unwilling to give further information.  We had
our toxicologists look at several of these cocktails, and they recommended
against using them.  One of the vendors admitted to me that they knew that
the laws would eventually catch up with this, and they have a limited
window of opportunity for these products.  When that happens, you are back
to square one again.

Fourthly, we do not have a waste management problem with scintillation
vials at MSU, even though we have a great volume each year.  We use the
regular cocktails, and then drum them up, ship them out through our regular
waste hauling vendor, and they are sent to a licensed vendor in Florida for
incineration.  (They use the flammable fluid as fluid, they are licensed
and inspected).   Even though we are in Michigan, ( and therefore barred
for the past 4 years from all the solid radioactive waste disposal sites),
we have no difficulties with this.  There are no regulatory problems; we
have talked with many regulators about this, and even have talked with the
disposal vendors as to whether they ever have any residues or contamination
that presents problems.  They do not.  But, the good news is, this is very
cheap!!!   The costs were almost equivalent to the costs of crushing the
vials as we used to do in the past.

As for the original question, when can they use the biodegradable
cocktails, many applications can use it, but a significant portion of our
faculty's research cannot.  Again, the big thing for them is the
re-validation of the work with the new method.  Data is often significantly
different from one cocktail to the next, as you probably already know.  

So, for these reasons, why switch?  The "safe" cocktails are not
necessarily safe, they present logistical problems in pouring, they cost
significantly more, and the normal flammable cocktails are not a disposal,
environmental or safety problem.  So, our thinking was/is, "if it ain't
broke, don't fix it".

Hope this is helpful.  I can share information on volumes and vendors if
anyone wants it.  Good luck.



************************************************************************
Kristin Erickson, Radiation Safety Officer
Office of Radiation, Chemical and Biological Safety
C124 Research Complex-Eng.
Michigan State University
East Lansing, Michigan 48824
Telephone: (517) 355-5008   Fax: (517)353-4871   Email: 10525kfb@msu.edu
************************************************************************