Absorption of arsenic by edible plants

Alf Christophersen alf.christophersen at basalmed.uio.no
Mon Mar 27 11:50:30 EST 2000


On Mon, 27 Mar 2000 10:37:39 -0500, wtmorgan at pilot.msu.edu (Bill
Morgan) wrote:

>So for real-world applications, you needn't use radioisotopes. That's a
>horribly expensive method. And at the end of that, you also come down to a
>tiny, unavoidable experimental error. It may be a smaller error than with
>other methods, but why go to the expense of using a radioisotope when you
>don't need it? You don't need to nail down the change to the last molecule
>of arsenic compound (and can't anyway, regardless of the method used). You
>do need to be fairly precise, but certainly not so precise as to detect one
>part in a billion change over background.

I think we have a fake discussion :-)

Why I suggested tracer was to prove that the leakage is just fractions
of the background in normal earth.

It is expensive, and should be done only once, to prove that the
leakage from the material is so little that there is no reason to
worry about it.

I would be really astonished if the test did show a leakage of more
than 1 mg pr kg treated wood pr year, that would give a dilution if
the molecules are scattered even in the nearest 10 cm distance ball
shell a dilution to several kg soil. And thus a concentration increase
less than half of background (over here in Norway with As-deficient
soil. In your country with As rich soil, it would be less than 1/10 of
background.

When it exceed more than 100 times, or more, it may be of concern. If
you let the wood rotten very quickly, maybe you would get high enough
concentration. With burning, most will evaporate (don't breath the
smoke, but more dangerous are probably smoke from nearly any other
treated wood since many of the compounds may give rise to TCDD,
tetra-chloro-diphenyl-dioxine, the most dangerous dioxine (but
possibly most toxic for experimental animals because the AH-receptor
is more sensitive in some laboratory animals than in humans,
1-4-dichlorobenzene used in toilet smellers, are probably much more
effective in binding AH-receptor.





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