Yew Tree Toxicity Question

[Les Hazlewood]

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.

The shed on my allotment is underneath the branches of a Yew tree which lies on the boundary of the allotment site. Since the autumn I've been saving run-off water from the shed roof to use on my vegetables. However, quite a few berries (and possibly a few leaves) from the Yew tree have been washed into the water tank. I realise now that I should have anticipated this, and strained the water before it went into the tank - but after-sight is wonderful thing !!!

I've read that Yew leaves are toxic and poisonous to many animals. Also that the red "avril" part of the berry is not toxic, but the seed inside the "avril" is extremely poisonous.

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 ?

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

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

I realise these might be quite difficult questions to answer, but I've got a "winter's worth" of saved water that I'd really like to try make use if rather than throw way.

Many thanks in anticipation ...

Les Hazlewood

[Pat Kiewicz]

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.

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

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.

[Billy]

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."

That is about 2 - 4 ounces.

The taxanes are diterpenes produced by the plants of the genus Taxus (yews).

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)