Absorption of arsenic by edible plants

Alf Christophersen alf.christophersen at basalmed.uio.no
Wed Mar 22 07:53:11 EST 2000

On Tue, 21 Mar 2000 17:35:07 -0500, wtmorgan at pilot.msu.edu (Bill
Morgan) wrote:

>Indeed so. The difference between arsenic and most of what we are familiar
>with, is that with arsenic, the concentration need not be all that high.
>It's pretty toxic stuff. Of course, that varies somewhat with the valence.
>So it's much more toxic than ethanol, not nearly as toxic as cyanide.

But still, selenide is about 5 times more toxic !

But, selenide is also proven to be even more toxic when there is too
little of it. The same seem to be the case of arsenic.

Almost every element has a profile where there is an optimum
concentration/amount in daily intake. Even mercury and lead may have
such a profile, but in very low concentrations. Mercury deficiency may
lead to loss of learning capability, but the optimum range for that is
at much lower concentration than those seen today in almost all food. 

With selenium, less than around 30-40 microgram per day, the less than
that, the more changes there is that your heart may get ill and
chances increases for developing cancer. About 1 mg pr day, and more,
the toxicity increases, first slight signs of changes in nail and
hair, but no danger for your life, but at concentrations around 10 mg
and above, it might be life threatening. In the form of H2Se, it is
extremely toxic, but also stinking like hell, so inusable for
intoxication. (By the way, H2S is also much more toxic than cyanide,
but it stinks like hell at around 1/1000 of the dangerous
concentration. If you know a room contain H2S and you go in there and
find it smell nothing, it is too late. Next second you are dead.

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