A great use of old tyres. Sitting on them should
be all right but would you grow veggies in them?
It wasn’t too long ago most car tyres ended up on bonfires
in autumn. Now though there are tighter
controls and a bit more understanding about just how polluting they can
be. Finding new and interesting things
to do with them can be entertaining and more and more people are being really
inventive when it comes to reusing them.
There are lots of play parks around that have soft surfaces made from
the ground up rubber after the steel wire has been taken out and we probably
sit on them as the new park benches have old tyres mixed in with old plastic
carried bags.
Other uses are:
·
Roof tiles
·
Road surfaces (the quiet type)
·
Children’s swings (cut to look like swans)
·
Earth ship houses with rammed earth inside them
as walls.
·
Growing flowers
·
Keeping down the silage sheets
·
Rolling down hills
·
Making sandals and furniture
The
biggest discussion though is whether it’s a good idea to use them for growing
vegetables. The dark colour absorbs
heat, the drainage is good and they are ideal to stack up for when you want to grow
spuds, strawberries or tomatoes. They can also be used effectively on steep
banks to stop soil erosion.
Under the EU Landfill Directive introduced a few years ago,
tyres have been classified as hazardous waste, with a ban on whole tyres being
sent to landfill. So do tyres leach out
toxins which are taken up by the plant to end up on our plates or is it just
bureaucracy gone mad?
A few tyre-ing facts
Tyres are extremely durable. During manufacture, natural
rubber is combined with synthetic rubber and treated with a cocktail of
chemicals, some toxic or known carcinogens, others more innocuous, to make the
tyre withstand all the forces that will act upon it on the road.
The forces that tyres have to resist on the road are:
sunlight, water, acidity, abrasion and friction with the road surface. Each of
these forces works in a different way on the tyre, but over time all break it
back down into its constituent parts.
During this process, the various chemicals and compounds are
slowly released through ‘off-gassing’, particulate matter or 'tyre dust', or as
chemicals, leaching out into water. Every tyre loses about 20% of its weight
during its lifetime on the road, getting slowly ground down and blowing away in
the wind.
Tyres and toxins
Most off-gassing occurs within the first year, for example,
that 'new carpet smell', and given that tyres typically are 3 to 5 years old
before being discarded, this would not really seem to be an issue.
What should be of greater concern to vegetable growers, is
the gradual erosion through water and sunlight, and any leeching of chemicals
and toxins that may occur to contaminate the surrounding soil, water and
anything grown in it.
What happens when
tyres degrade
The disintegration of tyres is well demonstrated when they
are used to weigh down covering sheets in silage areas. The tyres usually
degrade to point where the steel belt starts coming out of the tyres after ten
years.
Yet the effects aren't completely understood. A report by
the Environment Agency states that "little is known about the long-term
leaching of organic chemicals from tyres in landfill sites.”
Like many types of rubbish we produce today, we don't really
know what the individual effects of the leaching chemicals are. However, there
are strict controls in place for the proper disposal and handling of used
tyres, and it is illegal to dump them, with large fines for fly–tipping -
showing that problems with tyre disposal are appreciated.
Risky Business?
Mischa Hewitt is the author of Earthships in Europe and runs
Self Building an Earthship training courses in Brighton found a long list of
toxic chemicals in the tyres and wonders if it’s worth growing edibles in them.
“When it comes to growing food in tyres, why take the risk? Whilst the quantity
of toxic chemicals maybe small, we don't know the exact amount used in tyres
because of commercial secrecy.
People generally grow food organically for themselves to
avoid exposure to synthetic chemicals. It seems ironic that a 'Permaculture
way' of reusing tyres could be unintentionally reintroducing potentially
harmful chemicals back into the equation.”
Even lining the tyres with polythene before the soil is put
in doesn’t seem to attractive now.
