Absorption of arsenic by edible plants

Dan stevens at vtaks.com
Wed Mar 22 13:26:48 EST 2000


On Tue, 21 Mar 2000 14:17:17 GMT, "A. M. Hawk Widner"
<amhwidner at home.net> wrote:

>There are two schools of thought on that.  One school declares that nothing
>edible should be planted near the wood at all, in fact it should not be used
>for anything at all.  The other school is that it is probably relatively
>safe.  One of this latter group actually posted in here once result of a
>series of tests done on soil samples taken from near a pt wood retaining
>wall, effectively demonstrating that  the arsenic does not migrate far from
>the wood and  probably poses no health hazard.  This seems
>counter-intuitive; however, no one has yet posted actual test results
>refuting it.
>
	Well, this is the fundamental problem with all materials over
time; eventually they all decompose, even the mountains.  This is the
dilemma the government has with the Yucca mountain, Nevada nuclear
waste depository (dump)...they dont know if the contaminated materials
will be isolated long enough to become stable (some nuclear isotopes
can last tens of thousands of years, such as several plutonium ones).
Ground water seepage is the most prevalent problem at Yucca mountain,
so for the past 20-30 years, as tests go on and on and on and on and
on, nuclear contaminants, from used clothes to spent fuel rods, stack
up in nuclear plant sites.  Some techniques, such as dry cast storage,
provide long-term solutions, but aren't  fully supported and
implemented yet.

>Do any of you chemists know what arsenic does when exposed to soil
>conditions?  The above would make sense if arsenic decays into less toxic
>substances as it leaches from wood and comes in contact with soil and all
>that soil is.

Arsenic is an element;  it does not de-compose.  The only way to
change an element is by nuclear fusion, (or for larger elements,
fission and radioactive decay).  Fusion occurs at millions of degrees
in temperature, so when you have arsenic, its there to stay, unless
somehow removed and put somewhere else.

If you're worried about arsenic leakage, try and isolate the material
in question, whether wrapping the post in several plastic bags,
burying/surrounding in concrete, or a mix of both.  This will isolate
the wood from the environment for at least several
years/decades/longer.

Maybe theres even test results, showing which edible plants would be
safe to plant in such areas, but I dont know of any yet.

Dan




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