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Composting paper

It’s quite possible that when it comes to adding paper to compost, we may be fooling ourselves if we think we’re gardening organically. Consider your own composting process: is it anywhere close to being as thorough as a commercial process – which still lets chemical residues through? And what about paper pots, planted directly into the soil?

Paper: basically, it’s mashed-up wood – which is about as organic as it gets. So, is it OK to use in the garden? Specifically, is it OK to make newspaper plant pots, or add paper to your compost pile?

Most gardeners say ‘yes’ to things like newspaper, cardboard, egg cartons and toilet rolls. However, the usual recommendation for glossy magazines, junk mail etc is to recycle them and not put them into the compost.

I’d really, truly like to believe that newspaper and cardboard, etc, is OK.

If it was just mashed-up wood, there wouldn’t be a problem. And, the good news is that there still might not be a problem. However, having spent many years working in commercial printing, I still have some doubts.

compost bins pic, image

Composting - wouldn't it be nice if it was simple...

Until fairly recently, paper was bleached using chlorine. By-products of this process were dioxins, some of the most toxic chemicals known. Dioxins are ‘persistent environmental pollutants’ that build up in the body, mainly in fatty tissue, and cause many health problems – including birth defects and cancer. Because they’re so toxic, ‘elemental chlorine free’ (ECF) bleaching is now rare in the USA, Canada and Europe as it’s been replaced by ‘total chlorine free’ (TCF) bleaching which doesn’t use chlorine at all.

So that’s alright. Except…do you know where your paper came from? Very doubtful. And if it’s a recycled stock, do you know where the recycled fibres came from? Of course not.

Other chemicals in paper

Even though the dioxin problem may be substantially behind us (no pun intended re. the fatty tissue comment, above) there are loads of other chemicals involved in the manufacture of paper, some completely benign and others much less so. To see a full list, visit paperonweb.

While I have no idea what many of these chemical additives actually are, I’m equally sure that some of them don’t belong next to my cabbages – unless, of course, they completely break up in the composting process.

Chemicals in the ink

Ink, according to Wikipedia, ‘can be a complex medium, composed of solvents, pigments, dyes, resins, lubricants, solubilizers, surfactants, particulate matter, fluorescers, and other materials.’

Printing inks used to be petroleum based, but are now mostly soy based. Soy inks have many advantages aside from being healthier: they give a sharper image, are less likely to rub off onto the fingers, are cheaper, and are easier to clean from pulp when it’s being recycled.

However, soy oil doesn’t add colour. For that, heavy metals (and other chemicals) are still used, specifically zinc, barium, cobalt and manganese. Can composting deal with these?

Garden Organic and the Centre for Alternative Technology

A recent composting article on the Garden Organic website (one of my favourites) suggests adding paper. I phoned them and was told that as far as they were aware, chemicals in the paper were broken down in the composting process.

I was also told that the Centre for Alternative Technology (a wonderful place to visit if you ever have the chance) had been involved in a study which showed the heavy metals left behind were actually at a lower level of concentration than in the surrounding earth – which sounded very promising indeed. So, I called them too.

Unfortunately, the technical advisor I spoke to looked but couldn’t find any such study. He mentioned that they had worked with some pulp from the paper manufacturing process ‘years ago – more than 10’ but couldn’t find those details, either.

So, it seems that even the very people who should know about this stuff don’t have the answers.

Compost: The jury is still out

Commercial composting is a ‘hot’ process that can last up to 6 months. Certainly, many chemicals will be broken down by the end of it, but it’s hard to believe that all the ‘bad’ chemicals in paper and ink will just…vanish. Some other nasties, clopyralid for example, pass through the entire process and leave residues that are still chemically active.

I think…that there’s definitely more thinking to be done here.

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