> It would certainly be interesting to see how much actually makes it into
> other plants grown on the same ground after application, i.e. how
> biologically available the soil residues are.  Mu initial thought is that
> the levels would be quite a bit lower since the residues would likely have
> dispersed over a larger area,
>

Exactly.

I kept it to a point source which would have given max concentration if
planted over and over in the same place.

Dilution really complicates the problem since you go from Chemistry to
Process Chemical Engineering, or how to start with a and end up with b
while going through c, d, e, f and g to get there. Consider the complexity-
what is the soil makeup which includes density, surface area, chemicals,
catalysts,oxidizers, reducers, bonding agents, moisture, acidity (or
alkalinity) and on and on. Then add plowing, which increases the contact
with all of the above because of additional dispersal as well as a lot more
oxygen.

In the mean time, along with the half life, the amount is reduced because
it goes into the plant, but then might go back into the soil by being
plowed under. Then you have to figure what happened chemically in the plant
as well as the chemistry during the plant's breakdown in the soil.

Truth is, instead of making matters worse, the dispersion of the point
source should reduce the level of the pesticide in the soil. The point
source (repeating the planting in the exact place every year) is the worst
case, not the best case.

Remember what my point was- that you will never meet the spreadsheet
plateau because you do not have uniform dispersion, like a spray, and we
are talking about treated corn seed, a point source.

I am surprised that no one commented on the fact that the seed is three
dimentional while my planting area is two. Again, I was looking for max
concentration, and with a cubic foot of soil the amount of pesticide per
unit volume would be even less that the square foot example.

Bill Truesdell
Bath, Maine

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