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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://list.communitygarden.org/pipermail/community_garden_list.communitygarden.org/attachments/20090218/fcb83ff8/attachment.html> _______________________________________________ The American Community Gardening Association listserve is only one of ACGA's services to community gardeners. 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