Yes, thanks for the spreadsheet idea Jeremy.

 I assumed a dose of 1 unit each year, with a1 yr half life (half the
> product degrading over the course of a year).
>
> Note that the residues in the soil max out at an asymtote approaching
> the yearly dose.
>

The asymptote approaches 1 in this case (which happens to be the yearly
dose but only in this case).
Now change the number in the second column to see what happens with a
different half life (remember that I just posted the EPA values for half
lives of clothianidin in different soil types.  Let's not bother with the
extreme (20 years), but take some values that are certainly real:  a 2 year
half life and a 3 year half life.

With a two year half life the asymptote approaches three times the yearly
dose. (.75 was the multiplier, an approximation)

With a three year half life the asymptote approaches 6.7 times the yearly
dose. (.87 was the multiplier, also an approximation)

So while the fact that accumulation plateaus is reassuring, the fact that
the plateau level goes up so much with longer half life is a bit concerning
regarding clothianidin.   Does someone know (Paul perhaps) what is on the
label concerning warnings for how many years before you reuse?  It would be
interesting to do the spreadsheet with different half life lengths in
accordance with the label (just adding 1 to each year where it was
permitted).

The curves are steep at the beginning.

Stan

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