by Ivory King
Conventional methods of manufacturing clothing are incredibly resource intensive. From growing cotton, creating polyester, to dyeing and sewing, a huge amount of water, chemicals and labor are involved. Because of this, the clothing industry is the top polluter in the world second only to the petrochemical industry. A main contributor to textile pollution and resource gobbling is the dyeing process.
Azo dyes and heavy metals
With the discovery of coal tar based synthetic dyes, chemicals became the leading source of textile colorants. Synthetics became popular due to their infinite range of hues, color fastness and reliability. But the most common dyes, Azo dyes, contain chromium or copper. Other synthetic dyes also contain heavy metals, and ends up in the wastewater that gets created. This problem is exacerbated by the inefficient use of water in the dyeing process. Water treatment often cannot handle heavy metal contamination, and it ends up in waterways. As the book Eco-Friendly Textile Dyeing and Finishing describes, the volume and composition of the waste that dyeing fabrics creates has made it become one of the most significant sources of severe modern pollution.
While wastewater can reach drinking water in the countries that manufactured clothing, the chemicals continue to spread much further. A Greenpeace report found that UK rivers were polluted when consumers washed their new clothes at home - it washed out of the clothes and into local water. So not only are the carcinogenic substances in dyes affecting local people, they can even affect consumers in countries where these chemicals are banned.
Safe and natural dyes
Traditional natural dyes have offered some relief from the petro-nastiness of modern synthetic dyes. But some of these fell out of favor because they fade quickly, and there’s a limited color palette available. To keep some natural colors on the fabric, they require a mordant - effectively a substance that must be added to the dye in order for it to be more permanently affixed to the material. Unfortunately, many mordants are metal salts of chromium, copper or tin, and are toxic as well.
The safest way to use natural dyes involves a less toxic mordant in one bath, dye materials in another bath, and then rinsing the fabric of excess dye. While this makes for the lightest impact on the earth, and the fewest scary ingredients in the process, it still requires quite a bit of water! This is where efficiency practices come into play, and there’s much room for improvement.
Wild cotton comes in color
But not only are there natural or safe alternative to those nasty synthetic dyes, we can skip the whole process with wild, colorful cottons that are native to different areas of the world. Some heirloom varieties have been grown in the United States since before 1860, like the Mississippi Brown, or for several generations like Erlene’s Green, according to Virginia-based Southern Exposure’s Seed Exchange.
Since large-scale farming has spent decades breeding cotton to be stronger and softer, these older forms of cotton can be at a disadvantage in how they feel once they’ve been turned into fabric. To create longer fibers that are better suited for spinning into yarn and weaving, farmers are taking the color seeds and breeding them to make them better for fabric. In the meantime, textile engineers are blending colored cotton and stronger white cotton - using the white as a core for the colored cotton to wrap around, creating a best-of-both-worlds product that is strong and preserves color intensity.
Colored cotton seeds means we can grow fiber that not only skips the need for dyes themselves, but all the water that gets used during that process. And while this crop may be more expensive to grow, farmers can also charge more for it - and textile processors may spring for that price since they are saving on the dye costs.
While we are some distance away from more widespread use of naturally colored cotton in the textile industry, awareness is spurring adoption of safer and more efficient dye processes. Hopefully we can see better water usage and modified heirloom cotton in our clothing soon!