Dyed with madder

I’m not big on oatmeal, unless it’s cooked with soya milk for breakfast, but I suspect this is the natural colour of organic cotton.

Like most people, I prefer my clothes with a little colour. Unfortunately, the dye industry is another of fashion’s dirty little secrets. Vast amounts of water are used in the process (around 40-50l per kilo of fabric) and much is contaminated with dye and is not recycled. Dr Juncheng Hu from the South-Central University for Nationalities in Wuhan says that in China alone 1.6 billion tons of dye-laden wastewater is pumped into the river systems every year.

According to Dr Harold Freeman, CIBA professor of dyestuff chemistry at North Carolina State University, the problem may be as simple as the fact that the water is now coloured and the dye is not readily removed. But many dyes also contain toxic chemicals and heavy metals, for example, the popular Procion Turquoise MX-G contains 1 to 5% copper.

One solution is to use natural dyes, made from plants, such as madder and woad. Dr G Badri Narayanan from Purdue University calculated that if India only used natural dyes the amount of pollution released into the water would be halved.

In UK the newly founded www.cottonroots.co.uk uses natural dyes. The company make T-shirts and hoodies and specialise in customising organic and fairtrade clothes for the corporate sector. MD Susan Waters had the idea for the company as she was sipping a cup of tea in the Victoria and Albert Museum after viewing a clothing collection that was hundreds of years old yet still colourful. She thought that perhaps we should be copying our ancestors and using plants, minerals, salt and sunlight to dye clothes today too. The possibilities, she says, are endless from real tea-shirts to coffee-dyed aprons for baristas.

This is all very admirable, particularly in the commercial world, but many natural dyes are not without their problems either. First, it depends on the mordant used to fix the dye to the cloth – most are very toxic, such as chromium, and large quantities have to be added, typically in a weight equal to or double the weight of the fabric. Alum is one of the better mordants as it’s less toxic (this is what Cotton Roots uses). Secondly, natural dyes typically don’t bond with synthetic textiles like polyester or viscose.

Dr Hu and his colleagues have developed a way of cheaply removing dye from water. Plates coated with a material made from nickel oxide suck the dye molecules out of wastewater allowing the dye to be recycled. The system is not being used but does offer hope. Dr Freeman also claims that dyes are gradually becoming less toxic and more efficient so a smaller amount of water needs to be used in the dye baths. In Europe the label Oeko-Tex Standard 100 ensures that clothes have not been dyed with ‘chemicals harmful to health’.

So, if you’ve read this far, you’ll note the distinctly un-Christmassy tone of my last column for 2009. No, you don’t need a new outfit for Christmas parties, in a vibrant colour or otherwise, you’ve got plenty in your wardrobe.

And yes, I am having an attack of sour grapes: at five months pregnant I don’t fit into any of my party frocks.