Enzymes in textile processing

2 12 2011

Humankind has used enzymes for thousands of years to carry out important chemical reactions for making products such as cheese, beer, and wine. Bread and yogurt also owe their flavor and texture to a range of enzyme producing organisms that were domesticated many years ago.

In the textile industry, one of the first areas which enzyme research opened up was the field of desizing of textiles.  A size is a substance that coats and strengthens the fibers to prevent damage during the weaving process. Size is usually applied to the warp yarn, since this is particularly prone to mechanical strain during weaving.   The size must be removed before a fabric can be bleached and dyed, since it affects the uniformity of wet processing. Previously, in order to remove the size, textiles were treated with acid, alkali or oxidising agents, or soaked in water for several days so that naturally occurring microorganisms could break down the starch. However, both of these methods were difficult to control and sometimes damaged or discoloured the material. But by using enzymes, which are specific for starch, the size can be removed without damaging the fibers.

Enzymes used in textile processing - photo from Novozymes

It represented great progress, therefore, when crude enzyme extracts in the form of malt extract, or later, in the form of pancreas extract, were first used to carry out desizing.  Bacterial amylase derived from Bacillus subtilis  was used for desizing  as early as 1917. Amylase is a hydrolytic enzyme which catalyses the breakdown of dietary starch to short chain sugars, dextrose  and maltose.

Enzymes have been used increasingly in the textile industry since the late 1980s. Many of the enzymes developed in the last 20 years are able to replace chemicals used by mills. The first major breakthrough was when enzymes were introduced for stonewashing jeans in 1987 – because more than one billion pairs of denim jeans require some sort of pre-wash treatment every year. Within a few years, the majority of denim finishing laundries had switched from pumice stones to enzymes.

Today, enzymes are used to  treat and modify fibers, particularly during textile processing and in caring for textiles afterwards.  They are used to enhance the preparation of cotton for weaving, reduce impurities, minimize “pulls” in fabric, or as pre-treatment before dying to reduce rinsing time and improve color quality.  New processing applications have been developed for:

  • Scouring (the process of removing natural waxes, pectins, fats and other impurities from the surface of fibers), which gives a fabric a high and even wet ability so that it can be bleached and dyed successfully. Today, highly alkaline chemicals (such as caustic soda) are used for scouring. These chemicals not only remove the non-cellulosic impurities from the cotton, but also attack the cellulose leading to heavy strength loss and weight loss in the fabric. Furthermore, using these hazardous chemicals result in high COD (chemical oxygen demand) and BOD (biological oxygen demand)  in the waste water. Recently a new enzymatic scouring process known as ‘Bio-Scouring’ is being used in textile wet-processing with which all non-cellulosic components from native cotton are completely or partially removed. After this Bio-Scouring process, the cotton has an intact cellulose structure, with lower weight loss and strength loss. The fabric gives better wetting and penetration properties, making the subsequent bleach process easy and  giving much better dye uptake.
    • One of the newest products, PrimaGreen® EcoScour from Genencor, offers sustainability advantages for eco-scouring in cotton pretreatment, including 30 percent water savings and 60 percent energy savings compared to standard processing. In addition, the mild processing conditions result in improved fabric quality and enhanced color brightness after dyeing.
  • Bleaching – When bleaching cotton, a lot of chemicals, energy and water are part of the process. The company Huntsman has developed a wetter/stabilizer that maximizes the wetting and detergency of the bleaching process and a one-bath caustic neutralizer and peroxide remover in order to shorten the bleaching cycle, reduce energy and water required and deliver more consistent bleaching results. They have developed surfactants that are environmentally friendly (in that they do not contain Alkylphenol ethoxylates), and the system is both Oeko-Tex and GOTS approved.  After fabric or yarn bleaching, residues of hydrogen peroxide are left in the bath, and need to be completely removed prior to the dyeingprocess, using a step called bleach cleanup.  The traditional method is to neutralize the bleach with a reducing agent, but the dose has to be controlled precisely. Incomplete peroxide removal results in poor dyeing with distinct change of color shade and intensity, as well as patchy, inconsistent dye distribution. Enzymes used for bleach clean-up ensure that residual hydrogen peroxide from the bleaching process is removed efficiently – a small dose of catalase breaks hydrogen peroxide into water and oxygen.  This results in cleaner waste water and reduced water consumption.
    • In 2010, a life-cycle assessment was completed comparing PrimaGreen enzymatic bleaching to conventional textile bleaching methods. According to this LCA, if the enzymatic system were to see wide scale global adoption, the potential savings in freshwater consumption could be up to 10 trillion liters of water annually, and greenhouse gas reductions could range from 10-30 million metric tons. (1)
  • Biofinishing or biopolishing (removing fiber fuzz and pills from fabric surface) –  enzymatic biofinishing yields a cleaner surface, softer handfeel, reduces pilling and increases luster;
  • Denim finishing – In the traditional stonewashing process, the blue denim was faded by the abrasive action of pumice stones on the garment surface. Nowadays, denim finishers are using a special cellulase.  Cellulase works by loosening the indigo dye on the denim in a process known as ‘Bio-Stonewashing’. A small dose of enzyme can replace several kilograms of pumice stones. The use of less pumice stones results in less damage to garment, machine and less pumice dust in the laundry environment; in addition, it’s possible to fade denim without risk of damaging the garment.
  • European scientists have just announced a new and environmentally friendly way to produce textile dyes using enzymes from fungi. (2)

Because of the properties of enzymes, they make the textile manufacturing process much more  environmentally benign. (3)   Generally, they:

  1. operate under milder conditions (temperature and pH) than conventional process chemicals – this results in lower energy costs ( up to 120 kg CO2 savings per ton of textile produced) (4) ;
  2. save water – reduction of water usage up to 19,000 liters per ton of textiles bleached;
  3. are an alternative for toxic chemicals, making wastewater easier and cheaper to treat.
  4.  are easy to control;  do not attack the fiber structure with resulting loss of weight, resulting in better quality of material;
  5. better and more uniform affinity for dyes;
  6. contribute to safer working conditions through elimination of chemical treatments during production processes;
  7. are fully biodegradable.

So why is there a ruckus about enzymes being used in textile processing by GOTS and other organic certifying agencies?

(1)   http://primagreen.genencor.com/sustainability/lca_results/

(2)   http://www.just-style.com/news/eco-friendly-textile-dyes-use-enzymes-from-fungi_id112195.aspx

(3)   http://www.textiletodaybd.com/index.php?pid=magazine&id=52

(4)  http://www.europabio.org/sites/default/files/pages/lutz-walter-benefits-from-white-biotechnology-applications-in-the-european-textile-and-clothing-industry.pdf


Our oceans and your textile choices

23 02 2011

I just don’t know what it takes to change people’s habits.  We need a huge wake up call about the disastrous state of our oceans!  Our oceans are our life support system.  And they’re in trouble.

Because this is a blog about textile issues, I wanted to remind you that  the textile industry is the world’s #1 industrial polluter of fresh water.    So remember that  each time you choose a fabric that has been processed conventionally, in a mill which does not treat its wastewater, you’re  adding to the problem.  We’re all downstream.  And please also remember that a fabric marked “organic cotton” – though decidedly better than conventional cotton – is still a fabric which is 27% synthetic chemicals by weight,  processed at a mill which returned the untreated, chemically infused effluent to our oceans.

Sorce: NOLA.com

People once assumed that the ocean was so large that all pollutants would be diluted and dispersed to safe levels. But in reality, they have not disappeared – and some toxic man-made chemicals have even become more concentrated as they have entered the food chain.

Tiny animals at the bottom of the food chain, such as plankton in the oceans, absorb the chemicals as they feed. Because they do not break down easily, the chemicals accumulate in these organisms, becoming much more concentrated in their bodies than in the surrounding water or soil. These organisms are eaten by small animals, and the concentration rises again. These animals are in turn eaten by larger animals, which can travel large distances with their even further increased chemical load.

Animals higher up the food chain, such as seals, can have contamination levels millions of times higher than the water in which they live. And polar bears, which feed on seals, can have contamination levels up to 3 billion times higher than their environment.

Some scientists describe the chemical change in the ocean as throwing evolution into reverse: the chemical composition is going back toward the “primordial soup,” favoring the simplest organisms – indeed, algae, bacteria and jellyfish are growing unchecked –  and threatening or eliminating the more complex.  There are so many jellyfish in the ocean that many fisheries have given up their normal catch and are just harvesting jellyfish.[1] Clickhere to view Jellyfish Gone Wild by the National Science Foundation.  In fact, according to a report published in the Los Angeles Times, these most primitive organisms are exploding:  it’s a ‘rise of slime’ as one scientist calls it.   It’s killing larger species and sickening people.

Los Angeles Times report  in 2006 (click here to read the entire article)  sounds like something from a horror movie:  A spongy weed, reported to grow at 100 square meters per minute – literally fast enough to cover a football field sized area in an hour – has been plaguing fishermen in Australia.  The culprit, it was found, is a strain of cyanobacteria known as Lyngbya majuscula, an ancestor of modern-day bacteria and algae that flourished 2.7 billion years ago.  It has since shown up in at least a dozen places around the globe. It thrives in oxygen depleted water.   Once established, Lyngbya creates its own nitrogen fertilizer from decaying parts of the plant.

Many fishermen in Moreton Bay avoid working in the four months every year that Lyngbya clogs their waters because it is highly toxic to them.  When fishermen touch it, their skin breaks out in searing welts.  Their lips blister and peel.   As the weed blanketed miles of Moreton Bay over the last decade, it stained fishing nets a dark purple and left them coated with a powdery residue. When fishermen tried to shake it off the webbing, their throats constricted and they gasped for air.

After one man bit a fishing line in two, his mouth and tongue swelled so badly that he couldn’t eat solid food for a week.

Scientists in labs studying the bacteria couldn’t even be in the same room with it, the smell was so pungent.  It’s like “The Blob” come to life.

Scientist Jeremy Jackson says that we have forgotten the basic rule of thumb:  “Be careful what you dump in the swimming pool, and make sure the filter is working.”

And to add insult to  our ocean’s injury, the number of dead zones – where there is so little oxygen only microbes can survive – has doubled every 10 years since the 1960s [2].  In 2008, there were 400 dead zones [3].   So does that make you worry?  It should.   This is an example of what mathematicians call “exponential growth”, and it’s the kind of thing that doesn’t really impact us until we’re about to be kicked in the teeth.

To demonstrate the concept, there is an old story about a king who was presented with a gorgeous handmade chessboard by one of his subjects.  The king was delighted, and asked what the man wanted in return.  The courtier surprised the king by asking for one grain of rice on the first square, two grains on the second, four grains on the third etc. The king readily agreed and asked for the rice to be brought.   But there was not enough rice in the world to fill the courtier’s request (see note below) – the total amount of rice required would be 18,446,744,073,709,551,615 grains of rice.   This is about  460 billion tons, or 6 times the entire weight of the Earth’s biomass.

Source: Wikimedia Commons

And to see how the problem can become critical overnight (because according to the laws of exponential growth, the larger the quantity becomes, the faster it grows):  Imagine having a pond with water lily leaves floating on the surface. The lily population doubles in size every day and if left unchecked will smother the pond in 30 days, killing all the other living things in the water. We want to save the pond, so we check the lilies every day.   Yet day after day the plant seems small and so it is decided to leave it to grow until it half-covers the pond, before cutting it back. But the pond doesn’t becomes half covered until day 29 – leaving just one day to save the pond.  (4)

This concept has even led to the phrase “second half of the chessboard”, which refers to a point where an exponentially growing factor begins to have a significant impact.

So this news about the ocean dead zones – you might think that a dead zone the size of the state of Oregon is no big deal, but the area is growing exponentially.  How many years do we have until we reach the second half of the chessboard?

We must stop messing up our oceans.   If not for yourself, do it for your children. “You wouldn’t let a child open up a cabinet under the sink and start tasting the chemicals down there,” Fabien Cousteau says. “So why would you dump those chemicals down the drain and have them end up on your plate, which you then feed to your child?” (5)

NOTE regarding rice on the chessboard:

The total number of grains of rice on the first half of the chessboard is 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 + 256 + 512 + 1024 … + 2,147,483,648, for a total of exactly 232 − 1 = 4,294,967,295 grains of rice, or about 100,000 kg of rice, with the mass of one grain of rice being roughly 25 mg.

The total number of grains of rice on the second half of the chessboard is 232 + 233 + 234 … + 263, for a total of 264 − 232 grains of rice. This is about 460 billion tonnes, or 6 times the entire weight of the Earth biomass.

On the 64th square of the chessboard there would be exactly 263 = 9,223,372,036,854,775,808 grains of rice. In total, on the entire chessboard there would be exactly 264 − 1 = 18,446,744,073,709,551,615 grains of rice.

[2] Diaz, Robert J., and Rosenberg, Rutger, “Spreading Dead Zones and Consequences for Marine Ecosystems”, Science, August 2008.

[3] http://www.treehugger.com/files/2008/08/ocean-dead-zones-increasing-400-now-exist.php

(4)  Meadows, Donella H., Dennis L. Meadows, Jørgen Randers, and William W. Behrens III. (1972) The Limits to Growth. New York: University Books. ISBN 0-87663-165-0

(5)  http://www.oprah.com/world/Ocean-Pollution-Fabien-Cousteaus-Warning-to-the-World/4

Estimating the carbon footprint of a fabric

19 01 2011

We published this blog almost two years ago, but the concepts haven’t changed and we think it’s very important.   So here it is again:

Although most of the current focus on lightening our carbon footprint revolves around transportation and heating issues, the modest little fabric all around you turns out to be from an industry with a gigantic carbon footprint. The textile industry, according to the U.S. Energy Information Administration, is the 5th largest contributor to CO2 emissions in the United States, after primary metals, nonmetallic mineral products, petroleum and chemicals.[1]

The textile industry is huge, and it is a huge producer of greenhouse gasses.  Today’s textile industry is one of the largest sources of greenhouse gasses (GHG’s) on Earth, due to its huge size.[2] In 2008,  annual global textile production was estimated at  60 billion kilograms (KG) of fabric.  The estimated energy and water needed to produce that amount of fabric boggles the mind:

  • 1,074 billion kWh of electricity  or 132 million metric tons of coal and
  • between 6 – 9 trillion liters of water[3]

Fabrics are the elephant in the room.  They’re all around us  but no one is thinking about them.  We simply overlook fabrics, maybe because they are almost always used as a component in a final product that seems rather innocuous:  sheets, blankets, sofas, curtains, and of course clothing.  Textiles, including clothing,  accounted for about one ton of the 19.8 tons of total CO2 emissions produced by each person in the U.S. in 2006. [4] By contrast, a person in Haiti produced a total of only 0.21 tons of total carbon emissions in 2006.[5]

Your textile choices do make a difference, so it’s vitally important to look beyond thread counts, color and abrasion results.

How do you evaluate the carbon footprint in any fabric?  Look at the “embodied energy’ in the fabric – that is, all of the energy used at each step of the process needed to create that fabric.  To estimate the embodied energy in any fabric it’s necessary to add the energy required in two separate fabric production steps:

(1)  Find out what the fabric is made from, because the type of fiber tells you a lot about the energy needed to make the fibers used in the yarn.  The carbon footprint of various fibers varies a lot, so start with the energy required to produce the fiber.

(2) Next, add the energy used to weave those yarns into fabric.  Once any material becomes a “yarn” or “filament”, the amount of energy and conversion process to weave that yarn into a textile is pretty consistent, whether the yarn is wool, cotton, nylon or polyester.[6]

Let’s look at #1 first: the energy needed to make the fibers and create the yarn. For ease of comparison we’ll divide the fiber types into “natural” (from plants, animals and less commonly, minerals) and “synthetic” (man made).

For natural fibers you must look at field preparation, planting and field operations (mechanized irrigation, weed control, pest control and fertilizers (manure vs. synthetic chemicals)), harvesting and yields.  Synthetic fertilizer use is a major component of the high cost of conventional agriculture:  making just one ton of nitrogen fertilizer emits nearly 7 tons of CO2 equivalent greenhouse gases.

For synthetics, a crucial fact is that the fibers are made from fossil fuels.   Very high amounts of energy are used in extracting the oil from the ground as well as in the production of the polymers.

A study done by the Stockholm Environment Institute on behalf of the BioRegional Development Group  concludes that the energy used (and therefore the CO2 emitted) to create 1 ton of spun fiber is much higher for synthetics than for hemp or cotton:

KG of CO2 emissions per ton of spun fiber:
crop cultivation fiber production TOTAL
polyester USA 0.00 9.52 9.52
cotton, conventional, USA 4.20 1.70 5.90
hemp, conventional 1.90 2.15 4.05
cotton, organic, India 2.00 1.80 3.80
cotton, organic, USA 0.90 1.45 2.35

The table above only gives results for polyester; other synthetics have more of an impact:  acrylic is 30% more energy intensive in its production than polyester [7] and nylon is even higher than that.

Not only is the quantity of GHG emissions of concern regarding synthetics, so too are the kinds of gasses produced during production of synthetic fibers.  Nylon, for example, creates emissions of N2O, which is 300 times more damaging than CO2 [8] and which, because of its long life (120 years) can reach the upper atmosphere and deplete the layer of stratospheric ozone, which is an important filter of UV radiation.  In fact, during the 1990s, N2O emissions from a single nylon plant in the UK were thought to have a global warming impact equivalent to more than 3% of the UK’s entire CO2 emissions.[9] A study done for the New Zealand Merino Wool Association shows how much less total energy is required for the production of natural fibers than synthetics:

Embodied Energy used in production of various fibers:
energy use in MJ per KG of fiber:
flax fibre (MAT) 10
cotton 55
wool 63
Viscose 100
Polypropylene 115
Polyester 125
acrylic 175
Nylon 250

SOURCE:  “LCA: New Zealand Merino Wool Total Energy Use”, Barber and Pellow,      http://www.tech.plym.ac.uk/sme/mats324/mats324A9%20NFETE.htm

Natural fibers, in addition to having a smaller carbon footprint in the production of the spun fiber, have many additional  benefits:

  1. being able to be degraded by micro-organisms and composted (improving soil structure); in this way the fixed CO2 in the fiber will be released and the cycle closed.   Synthetics do not decompose: in landfills they release heavy metals and other additives into soil and groundwater.  Recycling requires costly separation, while incineration produces pollutants – in the case of high density polyethylene, 3 tons of CO2 emissions are produced for ever 1 ton of material burnt.[10] Left in the environment, synthetic fibers contribute, for example, to the estimated 640,000 tons of abandoned fishing nets in the world’s oceans.
  2. sequestering carbon.  Sequestering carbon is the process through which CO2 from the atmosphere is absorbed by plants through photosynthesis and stored as carbon in biomass (leaves, stems, branches, roots, etc.) and soils.  Jute, for example, absorbs 2.4 tons of carbon per ton of dry fiber.[11]

Substituting organic fibers for conventionally grown fibers is not just a little better – but lots better in all respects:  uses less energy for production, emits fewer greenhouse gases and supports organic farming (which has myriad environmental, social and health benefits).  A study published by Innovations Agronomiques (2009) found that 43% less GHG are emitted per unit area under organic agriculture than under conventional agriculture.[12] A study done by Dr. David Pimentel of Cornell University found that organic farming systems used just 63% of the energy required by conventional farming systems, largely because of the massive amounts of energy requirements needed to synthesize nitrogen fertilizers. Further it was found in controlled long term trials that organic farming adds between 100-400kg of carbon per hectare to the soil each year, compared to non-organic farming.  When this stored carbon is included in the carbon footprint, it reduces the total GHG even further.[13] The key lies in the handling of organic matter (OM): because soil organic matter is primarily carbon, increases in soil OM levels will be directly correlated with carbon sequestration. While conventional farming typically depletes soil OM, organic farming builds it through the use of composted animal manures and cover crops.

Taking it one step further beyond the energy inputs we’re looking at, which help to mitigate climate change, organic farming helps to ensure other environmental and social goals:

  • eliminates the use of synthetic fertilizers, pesticides and genetically modified organisims (GMOs) which is  an improvement in human health and agrobiodiversity
  • conserves water (making the soil more friable so rainwater is absorbed better – lessening irrigation requirements and erosion)
  • ensures sustained biodiversity
  • and compared to forests, agricultural soils may be a more secure sink for atmospheric carbon, since they are not vulnerable to logging and wildfire.

Organic agriculture is an undervalued and underestimated climate change tool that could be one of the most powerful strategies in the fight against global warming, according to Paul Hepperly, Rodale Institute Research Manager. The Rodale Institute Farming Systems Trial (FST) soil carbon data (which covers 30 years)  provides convincing evidence that improved global terrestrial stewardship–specifically including regenerative organic agricultural practices–can be the most effective currently available strategy for mitigating CO2 emissions.

At the fiber level it is clear that synthetics have a much bigger footprint than does any natural fiber, including wool or conventionally produced cotton.   So in terms of the carbon footprint at the fiber level, any natural fiber beats any synthetic – at this point in time.   Best of all is an organic natural fiber.

And next let’s look at #2, the energy needed to weave those yarns into fabric.

There is no dramatic difference in the amount of energy needed to weave fibers into fabric depending on fiber type.[14] The processing is generally the same whether the fiber is nylon, cotton, hemp, wool or polyester:   thermal energy required per meter of cloth is 4,500-5,500 Kcal and electrical energy required per meter of cloth is 0.45-0.55 kwh. [15] This translates into huge quantities of fossil fuels  –  both to create energy directly needed to power the mills, produce heat and steam, and power air conditioners, as well as indirectly to create the many chemicals used in production.  In addition, the textile industry has one of the lowest efficiencies in energy utilization because it is largely antiquated.

But there is an additional dimension to consider during processing:  environmental pollution.  Conventional textile processing is highly polluting:

  • Up to 2000 chemicals are used in textile processing, many of them known to be harmful to human (and animal) health.   Some of these chemicals evaporate, some are dissolved in treatment water which is discharged to our environment, and some are residual in the fabric, to be brought into our homes (where, with use, tiny bits abrade and you ingest or otherwise breathe them in).  A whole list of the most commonly used chemicals in fabric production are linked to human health problems that vary from annoying to profound.
  • The application of these chemicals uses copious amounts of water. In fact, the textile industry is the #1 industrial polluter of fresh water on the planet.[16] These wastewaters are discharged (largely untreated) into our groundwater with a high pH and temperature as well as chemical load.

Concerns in the United States continue to mount about the safety of textiles and apparel products used by U.S. consumers.  Philadelphia University has formed a new Institute for Textile and Apparel Product Safety, where they are busy analyzing clothing and textiles for a variety of toxins.  Currently, there are few regulatory standards for clothing and textiles in the United States.  Many European countries,  as well as Japan and Australia, have much stricter restrictions on the use of chemicals in textiles and apparel than does the United States, and these world regulations will certainly impact world production.

There is a bright spot in all of this:  an alternative to conventional textile processing does exist.  The new Global Organic Textile Standard (GOTS) is a  tool for an international common understanding of environmentally friendly production systems and social accountability in the textile sector; it covers the production, processing, manufacturing, packaging, labeling, exportation, importation and distribution of all natural fibers; that means, specifically, for example:  use of certified organic fibers, prohibition of all GMOs and their derivatives; and prohibition of a long list of synthetic chemicals (for example: formaldehyde and aromatic solvents are prohibited; dyestuffs must meet strict requirements (such as threshold limits for heavy metals, no  AZO colorants or aromatic amines) and PVC cannot be used for packaging).

A fabric which is produced to the GOTS standards is more than just the fabric:

It’s a promise to keep our air and water pure and our soils renewed; it’s a fabric which will not cause harm to you or your descendants.  Even though a synthetic fiber cannot be certified to  GOTS, the synthetic mill could adopt the same production standards and apply them.   So for step #2, the weaving of the fiber into a fabric, the best choice is to buy a GOTS certified fabric or to apply as nearly as possible the GOTS parameters.

At this point in time, given the technology we have now, an organic fiber fabric, processed to GOTS standards, is (without a doubt) the safest, most responsible choice possible in terms of both stewardship of the earth, preserving health and limiting toxicity load to humans and animals, and reducing carbon footprint – and emphasizing rudimentary social justice issues such as no child labor.

And that would be the end of our argument, if it were not for this sad fact:  there are no natural fiber fabrics made in the United States which are certified to the Global Organic Textile Standard (GOTS).  The industry has, we feel, been flat footed in applying these new GOTS standards.  With the specter of the collapse of the U.S. auto industry looming large, it seems that the U.S. textile industry would do well to heed what seems to be the global tide of public opinion that better production methods, certified by third parties, are the way to market fabrics in the 21st Century.

[1] Source: Energy Information Administration, Form EIA:848, “2002 Manufacturing Energy Consumption Survey,” Form EIA-810, “Monthly Refinery Report” (for 2002) and Documentatioin for Emissions of Greenhouse Gases in the United States 2003 (May 2005). http://www.eia.doe.gov/emeu/aer/txt/ptb1204.html

[2] Dev, Vivek, “Carbon Footprint of Textiles”, April 3, 2009, http://www.domain-b.com/environment/20090403_carbon_footprint.html

[3] Rupp, Jurg, “Ecology and Economy in Textile Finishing”,  Textile World,  Nov/Dec 2008

[4] Rose, Coral, “CO2 Comes Out of the Closet”,  GreenBiz.com, September 24, 2007

[5] U.S. Energy Information Administration, “International Energy Annual 2006”, posted Dec 8, 2008.

[6] Many discussions of energy used to produce fabrics or final products made from fabrics (such as clothing) take the “use” phase of the article into consideration when evaluating the carbon footprint.  The argument goes that laundering the blouse (or whatever) adds considerably to the final energy tally for natural fibers, while synthetics don’t need as much water to wash nor as many launderings.  We do not take this component into consideration because

  • it applies only to clothing; even sheets aren’t washed as often as clothing while upholstery is seldom cleaned.
  • is biodegradeable detergent used?
  • Is the washing machine used a new low water machine?  Is the water treated by a municipal facility?
  • Synthetics begin to smell if not treated with antimicrobials, raising the energy score.

Indeed, it’s important to evaluate the sponsors of any published studies, because the studies done which evaluate the energy used to manufacture fabrics are often sponsored by organizations which might have an interest in the outcome.  Additionally, the data varies quite a bit so we have adopted the values which seem to be agreed upon by most studies.

[7] Ibid.

[8] “Tesco carbon footprint study confirms organic farming is energy efficient, but excludes key climate benefit of organic farming, soil carbon”, Prism Webcast News, April 30, 2008, http://prismwebcastnews.com/2008/04/30/tesco-carbon-footprint-study-confirms-organic-farming%E2%80%99s-energy-efficiency-but-excludes-key-climate-benefit-of-organic-farming-%E2%80%93-soil-carbon/

[9] Fletcher, Kate, Sustainable Fashion and Textiles,  Earthscan, 2008,  Page 13

[10] “Why Natural Fibers”, FAO, 2009: http://www.naturalfibres2009.org/en/iynf/sustainable.html

[11] Ibid.

[12] Aubert, C. et al.,  (2009) Organic farming and climate change: major conclusions of the Clermont-Ferrand seminar (2008) [Agriculture biologique et changement climatique : principales conclusions du colloque de Clermont-Ferrand (2008)]. Carrefours de l’Innovation Agronomique 4. Online at <http://www.inra.fr/ciag/revue_innovations_agronomiques/volume_4_janvier_2009>

[13] International Trade Centre UNCTAD/WTO and Research Institute of Organic Agriculture (FiBL);    Organic Farming and Climate Change; Geneva: ITC, 2007.

[14] 24th session of the FAO Committee on Commodity Problems IGG on Hard Fibers of the United Nations

[15] “Improving profits with energy-efficiency enhancements”, December 2008,  Journal for Asia on Textile and Apparel,  http://textile.2456.com/eng/epub/n_details.asp?epubiid=4&id=3296

[16] Cooper, Peter, “Clearer Communication,” Ecotextile News, May 2007.

Breast cancer and acrylic fibers

16 09 2010

Just in case you missed the recent report which was published in Occupational and Environmental Medicine [1], a Canadian study found that women who work with some common synthetic materials could treble their risk of developing breast cancer after menopause.  The data included  women working in textile factories which produce acrylic fabrics   –  those women have seven times the risk of developing breast cancer than the normal population, while those working with nylon fibers had double the risk.

I found it interesting that the researchers justified their findings because “synthetic fibers are typically treated with several chemicals, such as flame retardants from the organophosphate family, delustering agents, and dyes, some of which have estrogenic properties and may be carcinogenic.”

These are the same organophosphate flame retardants and dyes that are used across the textile spectrum, and which are found in most textiles that we surround ourselves with each day.

But also let’s look at the fibers themselves.  The key ingredient of acrylic fiber is acrylonitrile, (also called vinyl cyanide). It is a carcinogen (brain, lung and bowel cancers) and a mutagen, targeting the central nervous system.  According to the Centers for Disease Control and Prevention, acrylonitrile enters our bodies through skin absorption, as well as inhalation and ingestion.  So could the acrylic fibers in our acrylic fabrics be a contributing factor to these results?

Acrylic fibers are just not terrific to live with anyway.  Acrylic manufacturing involves highly toxic substances which require careful storage, handling, and disposal. The polymerization process can result in an explosion if not monitored properly. It also produces toxic fumes. Recent legislation requires that the polymerization process be carried out in a closed environment and that the fumes be cleaned, captured, or otherwise neutralized before discharge to the atmosphere.(2)

Acrylic is not easily recycled nor is it readily biodegradable. Some acrylic plastics are highly flammable and must be protected from sources of combustion.

What about nylon?  Well, in a nutshell, the production of nylon includes the precursors benzene (a known human carcinogen) and hydrogen cyanide gas (extremely poisonous); the manufacturing process releases VOCs, nitrogen oxides and ammonia.  And finally there is the addition of those organophosphate flame retardants and dyes.

Of course, there are the usual caveats about the study, and those commenting on it said further studies were needed since chance or undetected bias could have played a role in the findings. In addition, according to Reuters, “the scientists said more detailed studies focusing on certain chemicals were now needed to try to establish what role chemical exposure plays in the development of breast cancer.”  So this is yet another area in which more research needs to be done.  No surprise there.

But in the meantime, did you know that many popular fabrics are made of acrylic fibers?   One of the most popular is Sunbrella outdoor fabrics.     Sunbrella fabrics have been certified by GreenGuard Children and Schools because the chemicals used in acrylic production are bound in the polymer – in other words, they do not evaporate.   So Sunbrella fabrics do not contribute to poor air quality, (you won’t be breathing them in), but there is no guarantee that you won’t absorb them through your skin.  And you would be supporting the production of more acrylic, the production of which is not a pretty thing.

And what about backings on fabrics?  Many are made of acrylic.  Turn those fabric samples over and see if there is a plastic film on the back – it’s often made of acrylic.  Upholsterers like fabrics to be backed because it makes the process much easier and stabilizes the fibers.

So I don’t know about you, but I think I’ll avoid those synthetics for now – at least until we know where we stand.

[1] Occupational and Environmental Medicine 2010, 67:263-269 doi: 10.1136/oem.2009.049817  (abstract: http://oem.bmj.com/content/67/4/263.abstract)  SEE ALSO:  http://www.breastcancer.org/risk/new_research/20100401b.jsp AND http://www.medpagetoday.com/Oncology/BreastCancer/19321

(2)  http://www.madehow.com/Volume-2/Acrylic-Plastic.html

Optical brighteners

14 07 2010

I got a call awhile ago from Harmony Susalla, founder and chief designer for Harmony Art  (if you haven’t seen her glorious fabrics go right now to www.harmonyart.com).  She was wondering about optical brighteners, and I discovered I couldn’t tell her much except to say that some are derived from benzene, which is a chemical nobody wants to live with.  GOTS allows the use of optical brighteners – with caveats (see below) – but they are supposed to reevaluate them “in two years from date of adoption” of version 2.0, which puts the reevaluation right about now.

So let’s explore optical brighteners, which are used extensively in:

  • Laundry detergents (to replace whitening agents removed during washing and to make the clothes appear cleaner.) – detergents may contain up to 0.2% whitening agents,
  • Paper, especially high brightness papers, resulting in their strongly fluorescent appearance under UV illumination. Paper brightness is typically measured at 457nm, well within the fluorescent activity range of brighteners. Paper used for banknotes does not contain optical brighteners, so a common method for detecting counterfeit notes is to check for fluorescence.
  • Cosmetics: One application is in formulas for washing and conditioning grey or blonde hair, where the brightener can not only increase the luminance and sparkle of the hair, but can also correct dull, yellowish discoloration without darkening the hair).  Some advanced face and eye powders contain optical brightener microspheres that brighten shadowed or dark areas of the skin, such as “tired eyes”.
  • as well as fabrics, which may contain 0.5% OBAs. A side effect of textile optical whitening is to make the treated fabrics more visible with Night Vision Devices than non-treated ones (the fluorescence caused by optical brighteners can easily be seen with an ordinary black light). This may or may not be desirable for military or other applications

You can still buy “bluing” – which is advertised to “whiten whites and brighten colors”.  Bluing works by removing yellow light to lessen the yellow tinge.   Optical brighteners – also called optical brightening agents (OBAs), fluorescent brightening agents (FBAs), and/or fluorescent whitening agents (FWAs) or “synthetic fluorescent dyes” –  work a bit differently.  Optical brighteners are chemicals similar to dyes which absorb ultraviolet light and emit it back as visible blue light – in other words, they fluoresce the ultraviolet light into visible light. The blue light emitted by the brightener compensates for the diminished blue of the treated material and changes the hue away from yellow or brown and toward white.

They are designed to mask yellow or brown tones in the fibers and make the fabric look cleaner and brighter than it would otherwise appear to the naked eye.   In other words, the undesirable color is made invisible to the eye in an “optical manner”.  Optical brighteners are used both on natural fibers (cotton, linen, hemp, silk) as well as in polymer melts for polyester and other synthetic fiber production.

Optical brighteners aren’t effective unless they remain in the fabric, and persist after washing.  They only last so long, until the point when they actually burn out and no longer do anything. They are also subject to fading when exposed long term to UV.

Brighteners can be “boosted” by the addition of certain polyols like high molecular weight polyethylene glycol or polyvinyl alcohol. These additives increase the visible blue light emissions significantly. Brighteners can also be “quenched”. Too much use of brightener will often cause a greening effect as emissions start to show above the blue region in the visible spectrum.

Optical brighteners are synthesized from various chemicals.  The group of chemicals which are called “optical brighteners” consists of approximately 400 different types listed in the Color Index, but less than 90 are produced commercially. (To get more information about the Color Index click here .)

Basic classes of chemicals used in OBAs  include:

  • Triazine-stilbenes (di-, tetra- or hexa-sulfonated)
  • Coumarins
  • Imidazolines
  • Diazoles
  • Triazoles
  • Benzoxazolines
  • Biphenyl-stilbenes

Using these chemicals, many companies compose their own chemical versions of an optical brightener, and sell it under a branded name, such as:

  • Blankophar R
  • Calcofluor
  • Uvitex
  • Bluton
  • CBS
  • DMS E=416
  • Kolorcron 2B

To find out what is in the optical brightener in any fabric, you must know the name of the optical brightener, and also the C.I. number (such as Brightener 24 or 220).  Then you can look up the chemical composition of the substance – but  only if you’re a subscriber to the Color Index database.  So it’s pretty difficult to confirm what is actually in an optical brightener.

In exploring some of the chemicals used in formulating optical brighteners,  I found one called cyanuric chloride, a derivative of 1,3,5 triazine.  Cyanuric chloride is used as a precursor and crosslinking agent in sulfonated triazine-stilbene based optical brighterners.   It is also classified as “very toxic”, “harmful” and “corrosive” by the EU and has several risk phrases identified with it – including R26 (“very toxic by inhalation”).  R26 is a substance which is specifically prohibited by GOTS.  So how can optical brighteners be allowed under GOTS?

The short answer is:  some are allowed, some are not – it depends on the chemical composition of each individual optical brightener.   Like dyestuffs, GOTS allows optical brighteners if they “meet all criteria for the selection of dyes and auxiliaries as defined in chapter 2.4.6, Dyeing.”  Those criteria include the prohibition of all chemicals listed in 2.3.1 and substances which are assigned certain risk phrases “or combinations thereof”.   But in order to know if a particular optical brightener meets these criteria, it’s necessary to know the chemical formula for that brightener.   And that takes a bit of detective work – and even so you might not be able to get final answers.  Don’t you begin to feel like a hamster in one of those wheels going round and round?

What are the problems associated with optical brighteners?
Some brighteners have been proven to cause allergic skin reactions or eye irritation in sensitive people.   The German Textiles Working Group conducted a health assessment of various optical brightening agents  following concerns of potential health risks to the public. It was found that there is a general lack of information on toxicity and a need for studies into dermal  absorption and the release of these substances from clothes.  While it has not been shown to negatively affect health, it has also not been proven safe.

They are known to be toxic to fish and other animal and plant life and have been found to cause mutations in bacteria.

Most OBAs are not readily biodegradable, so chemicals remain in wastewater for long periods of time, negatively affecting water quality and animal and plant life.  It is assumed that the substances accumulate in sediment or sludge, leading to high concentrations.
In wastewater, OBAs can also leach into groundwater, streams, and lakes. Since fluorescence is easy to detect,  optical brightener monitoring is an emerging technique to quickly and cost-effectivley detect the contamination of stormwater by sanitary wastewater.

REACH is the new European Union regulation which aims to  improve human health and the environment through better and earlier identification of the properties of chemical substances.  REACH stands for Registration, Evaluation, Authorisation and Restriction of Chemical substances.   REACH contains provisions to reduce the use of what are called “high volume production” chemicals.  These are defined as chemicals having annual production and/or importation volumes above 1 million pounds.  It is assumed that high volume production is a proxy for high exposure; in addition, large releases of low toxicity substances such as salts do cause environmental harm due to the sheer volume of the substance.
Much of the impact from optical brighteners comes in the form of large releases of low toxicity substances.  A number of these optical brighteners are listed as high and low production volume substances and so will be subject to REACH.   For example, C.I. Fluorescent Brightener 220 is listed as a high production volume chemical.

Our finite pool of worry

14 04 2010

Earth Day is coming up and I am having a hard time with climate change.  It’s such a big, complicated issue.  Climate change, according to Columbia University’s Center for Research on Environmental Decisions (CRED),  is  inherently abstract, scientifically complex, and globally diffused in causes and consequences.  People have a hard time grasping the concept, let alone taking action.  What can one person do to have an impact on such an overriding problem?

Turns out I’m not the only one who thinks that way.

Research shows that most Americans are  aware of climate change and even rank it as a concern,  but they don’t perceive it on a par with, say, the economic downturn or health care reform.   According to CRED,  most Americans do not currently associate climate change with disastrous impacts, such as drought, extreme weather events, and coastal flooding. And although most people can recite at least a few things they could do to help mitigate global climate change (like replacing light bulbs or carrying  reuseable grocery bags) – most are not doing them.

I’m ashamed to say,  I’m in that category.  I forget my grocery bags.  I use the car when I should really walk.  I  wash dishes by hand rather than using the dishwasher.  (What’s that?  Did you know that a running faucet can waste 2.5 gallons of water every minute!  So if I do the dishes by hand and it takes me 15 minutes, I’ve just wasted 37.5 gallons of water.  It’s better for me to run the dishwasher  – which uses only 11 gallons of water per use – even if it isn’t full. But I’m an old dog and habits die hard.)    It’s not easy, is it?  Don’t you just feel like throwing up your hands?

I’m faced with decisions every day in our fabric collection that could have far reaching effects – for example, a supplier wants to know if it’s o.k. to use the mill which has antiquated water treatment because that mill is closer (thereby reducing the energy needed for transport) and, not least, they’re cheaper!  There it is again –   Cost.  The bottom line in most decisions.  And if we decide to go with the sub optimal water treatment,  we might gain a cost advantage (so YOU might buy the fabric) but what will it mean in terms of the health of our children and the kind of world we leave them?

Each day I do more research into the effects that synthetic chemicals are having on us and our environment.  It chills me and I really believe that we’re causing ourselves harm.  We’re playing Russian roulette with the chemical mix we allow in our systems – thinking that since we’re not sick now it’s really nothing we have to worry about.   I absolutely believe that long term effects of our love affair with synthetic chemicals will be profound and that we must do something to stem the tide.  I proselytize to expectant mothers (I can’t help myself) about using organic fabrics and mattresses for their infants and themselves – because much of the research shows exposure in utero is when the most harm can be done.  But research also shows that future consequences are discounted, so people think they’ll just put off thinking of this until they have more time.

I guess what I’m getting at is the fact that we still behave in destructive ways – we don’t buy organic foods because it costs more (and it’s not gonna kill us – tomorrow, anyway),  we forget our reuseable grocery bags and we don’t take the time to replace light bulbs.  It’s like losing weight or exercising – we know it’s good for us, but we still don’t do it.

A report entitled The Psychology of Climate Change Communication, released  by CRED, looks at how people process information and decide to take action …  or not.  It seems people can deal with only so much bad news at a time before they tune out.   Social scientists call this the “finite pool of worry”.   And for really big threats like climate change, people are likely to alleviate their worries by taking only one action, even if it’s in their best interest to take more than one action.

For Americans, recycling has become the catchall green measure, the one action that anybody can do and feel that they’re doing something.  As with every action, there are costs and benefits.  The recycling of some products, such as computers and other electronics, creates a more severe strain on the environment that do other types of products, such as newsprint.  Again, even this topic is so fraught with subtleties and variety that dissecting it is hard.

I’d like to focus on plastics because the textile industry has concentrated sustainability efforts on recycled polyesters – many fabric collections claim green credentials because certain of their fabrics are made of recycled, rather than virgin, polyester.  And we all smile and pat ourselves on the back because we’re doing something – and hey, it doesn’t even cost any more.

Polyester is just one of the many plastics that are in use today;  plastic recycling – bottles, packaging, bags – has been adopted  as the mascot of our green efforts – as one school program says, it “teaches children social responsibility and reinforces learning to respect and take care of the environment”.   But what does plastic recycling really accomplish?

Stay tuned.

Textiles and water use

24 02 2010

Water.  Our lives depend on it.  It’s so plentiful that the Earth is sometimes called the blue planet – but freshwater is a remarkably finite resource that is not evenly distributed everywhere or to everyone.  The number of people on our planet is growing fast, and our water use is growing even faster.  About 1 billion people lack access to potable water, and about 5 million people die each year from poor drinking water, or poor sanitation often resulting from water shortage[1] – that’s 10 times the number of people killed in wars around the globe.[2] And the blues singers got it right: you don’t miss your water till the well runs dry.

I just discovered that the word “rival” comes from the Latin (rivalis) meaning those who share a common stream.  The original meaning, apparently, was closer to our present word for companion, but as words have a way of doing, the meaning became skewed to mean competition between those seeking a common goal.

This concept – competition between those seeking a common goal – will soon turn again to water, since water, as they say, is becoming the “next oil”;  there’s also talk of “water futures” and “water footprints”  – and both governments and big business are looking at water (to either control it or profit from it).  Our global water consumption rose sixfold between 1900 and 1995 – more than double the rate of population growth – and it’s still growing as farming, industry and domestic demand all increase.  The pressure is on.

Note: There are many websites and books which talk about the current water situation in the world, please see our bibliography which is at the bottom of this post.

What does all this have to do with fabrics you buy?

The textile industry uses vast amounts of water throughout all processing operations.  Almost all dyes, specialty chemicals and finishing chemicals are applied to textiles in water baths.  Most fabric preparation steps, including desizing, scouring, bleaching and mercerizing, use water.  And each one of these steps must be followed by a thorough washing of the fabric to remove all chemicals used in that step before moving on to the next step.  The water used is usually returned to our ecosystem without treatment – meaning that the wastewater which is returned to our streams contains all of the process chemicals used during milling.  This pollutes the groundwater.  As the pollution increases, the first thing that happens is that the amount of useable water declines.  But the health of people depending on that water is also at risk, as is the health of the entire ecosystem.

When we say the textile industry uses a lot of water, just how much is a lot?  One example we found:  the Indian textile industry uses 425,000,000 gallons of water every day [3] to process the fabrics it produces.  Put another way, it takes about 20 gallons of water to produce one yard of upholstery weight fabric.  If we assume one sofa uses about 25 yards of fabric, then the water necessary to produce the fabric to cover that one sofa is 500 gallons.  Those figures vary widely, however, and often the water footprint is deemed higher.  The graphic here is from the Wall Street Journal, which assigns 505 gallons to one pair of Levi’s 501 jeans [4]:

The actual amount of water used is not really the point, in my opinion.  What matters is that the water used by the textile industry is not “cleaned up” before they return it to our ecosystem.  The textile industry’s chemically infused effluent – filled with PBDEs,  phthalates, organochlorines, lead and a host of other chemicals that have been proven to cause a variety of human health issues – is routinely dumped into our waterways untreated.  And we are all downstream.

The process chemicals used by the mills are used on organic fibers just as they’re used on polyesters and conventionally produced natural fibers.  Unless the manufacturer treats their wastewater – and if they do they will most assuredly let you know it, because it costs them money – then we have to assume the worst.  And the worst is plenty bad.  So just because you buy something made of “organic X”, there is no assurance that the fibers were processed using chemicals that will NOT hurt you or that the effluent was NOT discharged into our ecosystem, to circulate around our planet.

You might hear from plastic manufacturers that polyester has virtually NO water footprint, because the manufacturing of the polyester polymer uses very little water – compared to the water needed to grow or produce any natural fiber.  That is correct.  However, we try to remind everyone that the production of a fabric involves two parts:

  • The production of the fiber
  • The weaving of the fiber into cloth

The weaving portion uses the same types of process chemicals – same dyestuffs, solubalisers and dispersents, leveling agents, soaping, and dyeing agents, the same finishing chemicals,  cationic and nonionic softeners, the same FR, soil and stain, anti wrinkling or other finishes – and the same amount of water and energy.  And recycled polyesters have specific issues:

  • The base color of the recycled polyester chips vary from white to creamy yellow, making color consistency difficult to achieve, particularly for the pale shades.  Some dyers find it hard to get a white, so they’re using chlorine-based bleaches to whiten the base.
  • Inconsistency of dye uptake makes it difficult to get good batch-to-batch color consistency and this can lead to high levels of re-dyeing, another very high energy process.  Re-dyeing contributes to high levels of water, energy and chemical use.
  • Unsubstantiated reports claim that some recycled yarns take almost 30% more dye to achieve the same depth of shade as equivalent virgin polyesters.[5]
  • Another consideration is the introduction of PVC into the polymer from bottle labels and wrappers.

So water treatment of polyester manufacturing should be in place also.  In fact there is a new standard called the Global Recycle Standard, which was issued by Control Union Certifications.   The standard has strict environmental processing criteria in place in addition to percentage content of recycled  product – it includes wastewater treatment as well as chemical use that is based on the Global Organic Textile Standard (GOTS) and the Oeko-Tex 100.

And to add to all of this, Maude Barlow, in her new book, Blue Covenant (see bibliography below) argues that water is not a commercial good but rather a human right and a public trust.  These mills which are polluting our groundwater are using their corporate power to control water they use – and who gives them that right?  If we agree that they have the right to use the water, shouldn’t they also have an obligation to return the water in its unpolluted state?  Ms. Barlow and others around the world are calling for a UN covenant to set the framework for water a a social and cultural asset, not an economic commodity, and the legal groundwork for a just system of distribution.


The World’s Water:  http://www.worldwater.org/

Water.org:    http://water.org/learn-about-the-water-crisis/facts/

Ground water and drinking water:  http://www.epa.gov/ogwdw000/faq/faq.html

New York Times series, Toxic Waters:  http://projects.nytimes.com/toxic-waters

Barlow, Maude, “Blue Covenant: The Global Water Crisis and the Coming Battle for the Right to Water”, The New Press, 2008

Water Footprint Network:  http://www.waterfootprint.org/?page=files/home

[1]Tackling the Big Three (air and water pollution, and sanitation), David J. Tenenbaum, Environmental Health Perspectives, Volume 106, Number 5, May 1998.

[2] Kirby, Alex, “Water Scarcity: A Looming Crisis?”, BBC News Online

[3] CSE study on pollution of Bandi river by textile industries in Pali town, Centre for Science and Environment, New Delhi, May 2006 and “Socio-Economic, Environmental and Clean Technology Aspects of Textile Industries in Tiruppur, South India”, Prakash Nelliyat, Madras School of Economics.

[4] Alter, Alexandra, “Yet Another Footprint to worry about: Water”, Wall Street Journal, February 17, 2009

[5] “Reduce, re-use,re-dye?”,  Phil Patterson, Ecotextile News, August/September 2008