permaculture

[Toby Hemenway <hemenway@jeffnet.org>]

Scott Pittman wrote:

> The ink itself does not contain any lead but today is contaminated with soy.  [snip] Some of the colored inks did, and may still, have toxic properties ie Cadmium,

Today all newspaper inks, including the colored ones, are soy derived (black ink has been soy based for about 20 years). Until a few years ago, colored inks on shiny paper (those ad inserts) needed a metal mordant to make them adhere, but I've been told that's been changed too. So newspaper shouldn't be toxic.

If there is lead in newspaper, it may come from the wood itself. On another list we've been discussing the toxicity of tires, and I found a great paper
http://www.dot.state.mn.us/environment/research/shredded_tires_paper.html
that compares toxics in shredded tire leachates to those from wood chips. The good news for tire pond builders is that tires don't leach much that's toxic; in fact, wood leaches more toxic organics. Both leach significant quantities of lead (though below toxic levels) and I suspect the lead is from leaded petrol sequestered by the trees. The tires did leach 5mg/L of zinc, but since topsoil contains 50mg/kg zinc, that's not too worrisome. 

Toby
_____________________________________________
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Gaia's Garden: A Guide to Home-Scale Permaculture, visit
http://www.chelseagreen.com/Garden/GaiasGarden.htm