HERB - Roots -Reply

[Norman White]

Hello Jin Liu Ch'ang here

>>> Christine A Seelye-King <mermayde at juno.com> 06/02/98 12:03pm >>>said <with copious snippage>:
> I do not generally use plants that are found on the roadside.  I believe >that originally the reason for this is the lead .....   I live in the center of >the city, so all of my yard is exposed to the air, but the front half is only >10 - 15 feet from the road.  What do you think?

Mundanely I am a PhD in soils and work in the Soil and Crop Sciences Dept. at Texas A&M.  Admittedly this is not my area (I am a clay mineralogist), but I dropped downstairs to see the guys who do have this for an area and got mixed opinions.  Most of the guys who worry about this stuff would not eat anything within 30 feet of a road more or less depending upon how busy the road is.  Effects for some microelements such as Mo and W derived from rubber, gas, etc. can be observed even further, up to 50 yards (this means they do not leach), as can the effects of the limestone spread on gravel roads.  The data on such effects is fairly hard to come by.  I can remember a friend named David Nagle, who did his dissertation at Florida in the late 1970s while I was there, found that W (Tungsten) which can replace Molybdenum to a degree in growing plants (peanuts?) could be detected a considerable distance from roads to the degree you could detect road influence by analyzing for the element.  Many of these elements are easily leached from soils but others such as W cannot.  I once read that you can detect the edges of fields that had undergone chemical fertilization by analyzing for Uranium which is always found at trace levels in Phosphate fertilizers as U is not leached to any degree.  For those that worry, the Uranium is so low in concentration that statistics are required to detect the differences above background levels.

She also mentioned:
>Second, I am growing echinacea purpurea for the first time, and I can't
>help but look at the plants and think, "150.00 a pound for dried
>echinacea root, hmmm,...
The echinacea roots that I saw yesterday here in the dry season in Texas were so small that if you harvested your whole yard you might get a couple of ounces.

>  Should I be concerned about using the roots of plants that grow 10 >feet from a busy road?  What about 30 feet, and down a terraced >hillside, with trees, bushes, etc. in between?
With what I wrote earlier in mind, if you worry about things enough to buy organic you would not want a root from within 10 feet of a road.

Jin Liu Ch'ang
a.k.a. Norman White
Dept. of Soil and Crop Sciences
Texas A&M University
College Station, TX  77843-2474
(409)-845-7386
gn-white at tamu.edu

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