and they'd make great raised beds--grow tomatoes out of the trunk!
----- Original Message -----
From: "Tom Brouillette" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 18, 2009 11:23 AM
Subject: Re: [Community_garden] old tires and rubber mulch -- and a new way
of manufacturing
Along the lines of tires and rubber mulch . . . I've always admired how
well old cars work as mulch: park 'em on a lawn, and nothing grows
underneath them! Parking old non-running wrecks in gardens might work well
at keeping weeds down: a great reuse of wreckage from our post-industrial
society.
At 08:31 AM 2/18/2009, Chris Reid wrote:
The internet is wonderful at how it can make the mundane look
authoritative, or history can be rewritten (government documents) at the
click of a button. Frnakly, I cannot find anything that says that whole
tires are toxic -- plenty saying how good they are (scrap tire industrial
groups, companies that sell plans for tire swings, the Texas consumer
product safety commission,....hmmmm)
In the case of the Noble Foundation link, where a description of how to
make yourself some rubber boards from tires is given, I looked at the
funding and purpose of the foundation and it is an oil/energy magnate's
fortune being spent down. Among the purposes of the foundation is to be
true to the ideas of the now-dead energy baron, Mr. Noble.
The Chairman is a lawyer, and I couldn't find a bio of the person in
charge of their agricultural division. You can't contact them via the
internet -- you have to call them or write to them. Thus, I could not
quickly send them a link to the shredded tire research and ask whether
creating dust and cutting up tires/making boards out of tires is such a
good idea. They may do great stuff, but I haven't found anyone touting
them as world thought leaders on environmental safety or agricultural
innovation.
In terms of what I have found on tires and toxicity to plants and humans,
I will below add in a link about the shredded rubber mulch and some of
what offgases and leaches from the shredded product. The tire itself may
be much more stable -- but I couldn't find anything about what the risks
are to kids and pets and water/environment over time (acute toxicity is
not the issue for people but it could be for some aquatic organisms).
The link: EHH hired the CT Agricultural Experiment Station to do a brief
study that attempted to identify what comes out of shredded mulch/ CAES
is a places that I have followed for years and can say without question
that it works very hard to keep its science true to science,. Their study
is also online, but it is a bit technical so I thought maybe the bullet
point results from EHH would be of more interest:
http://ehhijournal.org/TurfOpEdKY.html
Astroturf is essentially using these toxic rubber tires to make something
kids and professional ball teams play on. It also offgasses and leaches.
I don't think we are doing our kids any favors.
But does the whole tire pose the same risk as the shredded tire? Or do we
just not want it anywhere near our gardens? Part of the leaching
properties and offgassing of toxic substances is stepped up by the
shredding of the tires, since more surfaces are exposed to air and water
and microbes. The question gardeners also have to consider is, does
"less toxic" make it a good thing to have around? Sunlight and acid rain
may act on the tire and cause it to release more toxins. There are also
variations in what is contained in the tire based on the type of tire you
use -- e.g. spare tires don't have steel in them like steel belted
radials, and one site said summer tires are supposed to be more toxic than
winter tires. (Does that make winter tires safe? No explanation given.)
In terms of the effect on garden plants of shredded rubber and mulch, the
testers observed zinc leaching out of the tires and chrysanthemums being
affected by the initial leaching, which then stopped during the rest of
the testing period. Another report described some toxicity to tomatoes
from tires. The more acidic the soil, the more the zinc in it was a
toxicity issue for plants (the acidic soil makes the zinc more available
to the plants). Zinc is a common urban heavy metal pollutant anyhow.
Are we getting more tire dust in the air around the gardens from
screeching tires and normal wear on pavements than from whole tires? I
don't know.
One Swedish report said that due to leachates from tires causing damage to
aquatic organisms, they saw a need to evaluate the potential for
environmental hazard to blown tires along their roadways. They found the
leachates that were created artificially to simulate what might happen
from tires near waterways to be far more toxic to aquatic life than they
had originally estimated.
Are tires less dangerous as whole tires in small numbers than in
landfills? I couldn't find any statements one way or another. They make
great rat habitat if they're just sitting around waiting to be used,
though.
The study by CAES above cost $2000 to do - not very much money. I am
puzzled that we have spent probably billions manufacturing these tires,
and yet it is so comparatively hard to find a study on their safety or
lack thereof.
One of the characteristics of the world we live in is that we have a
manufacturing approach that starts a product off either useful but later
useless (rather than neverendingly able to be used), and we accept
toxicity as a given in our environment, rather than trying to design
things that are not toxic and leave the world cleaner.
Final link is to Bill McDonough's book, Cradle to Cradle. It is not an
inexpensive paperback because he walks the talk -- it is printed not on
dead trees, but on an industrial chemical (polymer?) that could be used
for books and then the ink washed off and the pages recycled to make more
books from the same chemical mass - no trees involved. The "paper" feels
like vellum. I found the book's rethinking of how we manufacture
tremendously inspiring --and at this moment of hesitation in our economy
where things are not working, perhaps it's time to invest in doing our
industry differently so that each product has the potential to make the
world cleaner, not dirtier, and stoically accepting that we are
manufacturing our own demise is not a personality characteristic required
of our kids or ourselves to live on the planet.
Here's the link to the amazon preview:
http://www.amazon.com/gp/reader/0865475873/ref=sib_dp_pt#reader-link
I
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how to join, please go to http://www.communitygarden.org
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