Mollyanne M Meyn wrote:
I too have questioned the toxicity. I think the question is whether or not plants take up toxic compounds from tires, and whether or not they metabolize toxic compounds.
Ain't nothing that can metabolize Zinc -- too much and your plant dies. Cadmium, alas, is sucked right up in plants (grains just love it) and stores such that when WE eat the plants, all that nasty stuff is released into our bodies and WE aren't able to process or store it.
I've read that sometimes plants can "purify" toxic conditions in the soil, which I assume to mean that toxic compounds are broken down into non-toxic elements and compounds by plant metabolism.
Uh, no. There are several bacteria which will break down the toxic to into the non-toxic, but the phytoremediation has ALWAYS meant using a plant that will absorb high levels of a toxin and still live, then harvesting the plant and burning the whole thing in a toxic waste incinerator. Check the archives of this list -- there were some great explanations of the process in the past.
If the soil is low in zinc, then maybe the tires are a good thing?
It's a very rare soil, especially in an urban area, that is low in zinc.
It is hard to find info about toxic chemicals that leach from tires when left in the soil.
Not a research subject that USDA has been/would be willing to fund under current administration. It gets worse when you want to find info on sewage sludge! ;-P
Easier to find out about the toxic chemicals that are released when tires are burned.
Always consider an active soil to be a slow burn -- if you've got plenty of microorganisms in your soil, "burning" is taking place. If toxins are being released through burning, your microbes are probably doing the same thing on a much longer timeline.
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