Science Questions

Where does all the rubber worn from tyres go?

Sun, 4th Sep 2011

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Question

Alan, Orpington asked:

My question is about the rubber that is lost from the surfaces of tyres throughout the world. All the time, every country, 24 hours a day, tyres are losing minute amounts of rubber and wearing the tyres out. Where does it all go? Does it turn into dust? Does it mix in with our water systems? Is there a big well at the bottom of the sea where itís gathering? Where does it go to and what does it do?

Answer

Dave - If you've ever changed a bicycle tyre youíll know where quite a lot of it ends up and thatís all over your hands, because you're covered in a horrible black gunge which I think is mostly tyre rubber.  Then what's going to happen to a kind of black powder all over the road, itís going to get caught up by water and washed away.  I imagine that rubber is a natural thing so eventually, some of that could be broken down Iíd thought biologically.

Chris -  Itís vulcanised though isn't it, because itís got some sulphur added so it cross-links,  making it harder to breakdown as itís been modified that way.  I think itís quite persistent.

Dave -   Okay, itís going to be a very slow process so I wouldíve thought most of it ends up in sediments in streams and rivers, and it will slowly get fossilised in there or at the bottom of the sea, where it will sit until itís degraded and turned maybe back into oil.

Chris -   It turns into millions of tonnes of rubber on the roads every year actually. I recently calculated how many tonnes of rubber we get through the western world every year - just some simple back of the envelope calculations: millions of tonnes of rubber get used every year and as those tyres are being replaced, you can never work out that there are millions of tonnes of rubber that are worn out onto the road surfaces.

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I reckon it ends up in the same place as my missing socks. graham.d, Tue, 6th Sep 2011

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