In article
,
Pat Kiewicz wrote:

Les Hazlewood said:


I'm posting this in the hope that someone is able to answer a question
about using water that is contaminated with berries and possibly leaves
from a Yew tree.

snip

Its early in the growing season, and I haven't used any of this water
yet, but is it safe to do so, ie:

a) Is is safe to eat vegetables that have been watered using this
contaminated water ?

I really can't imagine that they wouldn't be safe to eat. (Washing them
with clean water before eating is probably something you already do,
I assume.)

Relax! There's far more risk just in travelling to your allotment. Even the
manure you might use in your garden has more potential to harm you.


b) Will the leaves / seeds continue to contaminate the soil, or will the
toxins in them break down ?

Certainly the toxins break down. I've never heard of any yew-created
dead zones. Have you?

c) Does it make any difference if I strain the water before using it ?

If it makes you feel better, certainly, by all means.

I'm not usually this testy, but, I have to say, if this is something you have
time to worry about, you are a lucky man.

If it makes you feel any better, Wikipedia says,"Fatal poisoning in
humans is very rare, only occurring after eating a lot of yew foliage.
The major toxin is the alkaloid taxane. The lethal dose is reported to
be between 50 and 100 grams."
http://en.wikipedia.org/wiki/Taxus_baccata#Toxin
That is about 2 - 4 ounces.

The taxanes are diterpenes produced by the plants of the genus Taxus
(yews).
http://en.wikipedia.org/wiki/Taxane
At the above site you will see that taxanes are rather large molecules
which a plant would have difficulty adsorbing. They are the type of
molecules that plants make from scratch.

The obvious questions to me are does anything grow near the yew tree,
what is the dilution of yew material in grams/liters of water, and how
much water will be used per 100 sq. meters?

I've found nothing to indicate that vegetables will take up the major
toxin found in yew, the alkaloid taxane.

To re-cap, you have dilution, degradation of the toxin in the soil, and
the selectivity of absorption by the plants protecting you.

You owe me a pint ;o)
--
http://www.youtube.com/watch?v=hYIC0eZYEtI
http://www.democracynow.org/blog/2011/3/7/michael_moore
http://www.youtube.com/watch?v=eZkDikRLQrw
http://www.youtube.com/watch?v=MyE5wjc4XOw