Hi
Thanks for asking. I'd been wondering about that, as I've recently
started a compost heap.
Here's what "Weblife: Humanure Handbook" has to say:
"Yes, newspaper will compost, but there are some concerns about
newsprint. For one, the glossy pages are covered with a clay that
retards composting. For another, the inks can be petroleum-based
solvents or oils with pigments containing toxic substances such as
chromium, lead and cadmium in both black and colored inks. Pigment for
newspaper ink still comes from benzene, toluene, naphthalene, and
other benzene ring hydrocarbons which may be quite harmful to human
health if accumulated in the food chain. Fortunately, quite a few
newspapers today are using soy-based inks instead of petroleum-based
inks. If you really want to know about the type of ink in your
newspaper, call your newspaper office and ask them. Otherwise, keep
the glossy paper or colored pages in your compost to a minimum.
Remember, ideally, compost is being made to use for producing human
food. One should try to keep the contaminants out of it, if possible.
"Wood’s End Laboratory in Maine did some research on composting ground
up telephone books and newsprint, which had been used as bedding for
dairy cattle. The ink in the paper contained common cancer-causing
chemicals, but after composting it with dairy cow manure, the
dangerous chemicals were reduced by 98%.92 So it appears that if
you’re using shredded newspaper for bedding under livestock, you
should compost it, if for no other reason than to eliminate some of
the toxic elements from the newsprint. It’ll probably make acceptable
compost too, especially if layered with garbage, manure, and other
organic materials."
( http://www.weblife.org/humanure/chapter3_12.html )
And here's what the "Master Composter" site has to say:
"With regard to composting newspapers with black ink, I have only
heard one mention of controversy. Otherwise, I have found that
composting newspapers is acceptable. (As mentioned above, it is not
usually recommended for use in a backyard pile because of the problems
of matting, low nutrient value and slow decomposition.) The one
controversial source was the book "Let It Rot" by Stu Campbell. He
says that the carbon black ink contains polycyclicaromatic
hydrocarbons (PAH) which are a known carcinogen. Stu says
"Although the jury is still out, most scientific research to date
indicates that PAHs are rendered inert by the temperatures of a hot
compost pile, the biological activity, and the acids in the soil. Most
newspaper inks no longer contain heavy metals, and most colored
newsprint now uses vegetable dyes, so as long as you don't intensively
compost with newspapers you can use it as a carbon source."
"With regard to newspapers, A Green Guide to Yard Care published by
the Texas Natural Resource Conservation Commission says, "Most inks
today are safe for garden use." To be completely safe, call your
newspaper and ask about the ink or use compost made from newspapers on
non-edibles like your lawn, ornamentals, flowers, and trees, rather
than your vegetable garden.
"Do NOT compost advertising inserts. Ad inserts are printed by someone
other than the newspaper. Most companies still print inserts with
heavy metal inks, especially the glossy ones. Some colored inks have
heavy metals in them which, in large quantities, are toxic to
microorganisms. Small quantities such as the occasional colored ad in
the newspaper have negligible effects.
"With society's emphasis on recycling, most newspapers have started
using vegetable dyes for colored advertisements and the comics. (If
your newspaper uses vegetable dyes, you can compost the comics, too.)
Unfortunately, there is no way to be certain which dye they use by
looking at the printed page. To make sure, call your local newspaper
and ask them if they use vegetable dyes."
( http://www.mastercomposter.com/ref/orgmat4.html)
So it looks like I'm going to be using "normal" newsprint, and taking
the shiny stuff to the paper recycle bin.
Hope that helps. Anything you need clarifying, just ask.
Willie-ga
There is an archive discussion forum which debated the topic at
"Compost Chemical Issues"
( http://www.mastercomposter.com/archive/arc_chem.html#INK )
Google searches used
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