permaculture

[John Schinnerer <eco_living@yahoo.com>]

Aloha,

> I know there's cadmium in tyres that will release under acidic
> conditions  - the theory I was given about making tyre gardens was 
> that if there's lots of humus and regular lime applications this 
>shouldn't be a big problem - I've been asked about this by a few 
>people recently and would like more info myself, especially researched

>info (not just anecdotal)

Some brief excerpts from one of the eight reports in the compilation I
just mentioned:

"In a study conducted for the Minnesota Pollution Control Agency
(1990), it was reported that metals are leached from tire materials in
the highest concentrations under acid conditions.  This study indicated
that Ba, Cd, Cr, Pb, Se and Zn concentrations in adjusted acid
conditions (pH of 3.5 to 5) exceed the recommended allowable limits set
...for drinking water. ... This study also found that polynuclear
aromatic hydrocarbons and total petroleum hydrocarbons are leached from
tire materials in the highest concentration under basic conditions (pH
of 8.0).  This study indicates potential problems under either acidic
or base conditions, i.e., if waste tires are utilized in locations
where exposure to pH extremes is expected."

This is in the report "Development of Engineering Criteria for Shredded
Waste Tires in Highway Applications" - they were looking to see if
shredded tires used as a component of fill, base, embankement, etc.
would present a leachate hazard to groundwater, that sort of thing.

So there's a snippet of researched info...you might be able to get a
copy of the report if you want lots more details (not all of it is on
environmental properties - a lot is physical engineering stuff).  Try
their web site for contact info, as I don't have any - it's from the
Geotechnical Engineering Program in the Dept. of Civil & Environmental
Engineering at University of Wisconsin, Madison.

Anecdotally speaking, IMO visible tires are just plain ugly, whether
whole, inside out, in pieces, whatever (with the possible exception of
shoe soles, where they're not very visible... ;-).  I used some for
planters years ago - grew some tasty beans, but they were *ugly*
planters.  There's lots of better things to use that feed the soil
instead of having to be protected from it.  I suppose it seemed like a
clever idea at the time...


=====
John Schinnerer, MA
-------------------------
- Eco-Living -
Cultural & Ecological Designing
Food - Water - Shelter - Community - Technology
john@eco-living.net
http://eco-living.net

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