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Subject:
Re: It's the kids
From:
Bill T <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Fri, 2 Apr 2010 09:29:40 -0400
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> >>>Dave Cushman's site ...... the .06%  equates to 60ppm
>
>
> >sorry I might be wrong but 100 ppm = 0.01%;  and
>  0.06% = 600 ppm
>
> >Can anyone comment?
>
> That's what I compute.
> Mike in LA
>

Me too. Always pays to use a calculator rather than eyeball the zeros. Sorry
for the error. Too many zeros. They seem to be my downfall in this
discussion.

Actually, you do not have to even use ppm that since the max found in the
Sammatero study was

Day 9 larvae had 5798 ng carvacrol / larva and 227 ng thymol / larva
>

If you convert to ėg (1  ėg  = 1,000 ng)  gives .227 ėg/larva for Thymol
(unless my zeros are off again), and it is well below the LC50 of 150.7 ėg /
larva.

The problem with using ppm and mass (and even concentrations) is really
apparent here and relates back to my comments on picograms and ppt. They are
not the same.

You have to know the amount the bee will consume to get the actual dosage.
That I will leave to someone else as I have no idea how much liquid feed a
bee consumes. Then you have to determine what part of that is Thymol. I will
leave that as a problem for the student. I am done with converting
concentrations to mass and dosages.

Did I say that picograms and ppt are not the same? It also works with ppm
and micrograms. You really have to stay with one measurement system,
otherwise things can get really confused.

Bill Truesdell
Bath, Maine

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