At 08:29 AM 1/23/01 -0700, you wrote:

>I'm curious why dry weight is of interest unless a nitrogen analysis or other
>such work is planned, and I wonder if anyone has done any analysis to see how
>much of what  comes off under such heat is moisture?

Alan:

When we started, all of the literature about bee poisoning was reported as
some concentration X or dose per bee, and in court cases witnesses would
say that all of the dose response studies reported how much the bee was
exposed to, not what ended up in the bee.  We also heard that bees varied
so much, that one could never make any estimates of what the maximum or
minimum amount per bee might be as a result of these dose trials.

But, most beekeepers who have sustained a pesticide kill have dead bee
bodies as their only evidence, and the only option is to analyze the bee
bodies for residues.  Again, we found that there was no standard for
reporting body burden residues in the U.S. and other countries.

The only consistent way to compare the results is to determine the amount
of the pesticide per bee on a dry weight basis.  Not all labs or studies do
this, so you will find results expressed on a wet weight basis, a dry
weight basis, and some unusual (to us in the U.S.) values such as mg% (that
one took us some time to figure out).  But, if you have an idea of the
moisture content of a bee (and yes, there may be some volatiles lost, but
the weight of these compared to that of water in the bee is likely to be
small), the dry weight, and the wet weight - you can generate estimates of
concentrations of the pesticide or contaminant per bee - even if the
original study or lab did not address this issue.  Obviously, these are
estimates, covering a range of values - but it does put some brackets on
the values.

Cheers

Allen
Jerry J. Bromenshenk, Ph.D.
Director, DOE/EPSCoR & Montana Organization for Research in Energy
The University of Montana-Missoula
Missoula, MT  59812-1002
E-Mail: [log in to unmask]
Tel:  406-243-5648
Fax:  406-243-4184
http://www.umt.edu/biology/more
http://www.umt.edu/biology/bees