The mission of these Green Pages is to provide a clear, concise, open stage for presenting views and issues that will enable consumers to make informed decisions on healthy, environmentally sound and sustainable choices. Another goal is to expose the myths and the propagation of misleading information presented to the consumer by companies and the industry providing services and products. These pages are not a product created because of current political, social, economical or environmental conditions or trends, they are the continued respect, awareness, actions and conservative lifestyle that have always been a part of the 46 years of my life.
Some revealing facts behind the production of bamboo fabrics
There are two ways to process bamboo to make the plant into a fabric: mechanically or chemically. The mechanical way is by crushing the woody parts of the bamboo plant and then use natural enzymes to break the bamboo walls into a mushy mass so that the natural fibers can be mechanically combed out and spun into yarn. This is essentially the same eco-friendly manufacturing process used to produce linen fabric from flax or hemp. Bamboo fabric made from this process is sometimes called bamboo linen. Very little bamboo linen is manufactured for clothing because it is more labor intensive and costly.
Chemically manufactured bamboo fiber is a regenerated cellulose fiber similar to rayon or modal. Chemically manufactured bamboo is sometimes called bamboo rayon because of the many similarities in the way it is chemically manufactured and similarities in its feel and hand.
Most bamboo fabric that is the current eco-fashion rage is chemically manufactured by “cooking” the bamboo leaves and woody shoots in strong chemical solvents such as sodium hydroxide (NaOH – also known as caustic soda or lye) and carbon disulfide in a process also known as hydrolysis alkalization combined with multi-phase bleaching. Both sodium hydroxide and carbon disulfide have been linked to serious health problems. Breathing low levels of carbon disulfide can cause tiredness, headache and nerve damage. Carbon disulfide has been shown to cause neural disorders in workers at rayon manufacturers. Low levels of exposure to sodium hydroxide can cause irritation of the skin and eyes. Sodium hydroxide is a strong alkaline base also known as caustic soda or lye. In its dry crystalline form, caustic soda is one of the major ingredients of Drano. This is basically the same process used to make rayon from wood or cotton waste byproducts. Because of the potential health risks and damage to the environment surrounding the manufacturing facilities, textile manufacturing processes for bamboo or other regenerated fibers using hydrolysis alkalization with multi-phase bleaching are not considered sustainable or environmentally supportable.
While specifics can vary, the general process for chemically manufacturing bamboo fiber using hydrolysis alkalization with multi-phase bleaching technology – which is the dominate technology for producing regenerated bamboo fiber – goes like this:
- Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted and crushed;
- The crushed bamboo cellulose is soaked in a solution of 15% to 20% sodium hydroxide at a temperature between 20 degrees C to 25 degrees C for one to three hours to form alkali cellulose;
- The bamboo alkali cellulose is then pressed to remove any excess sodium hydroxide solution. The alkali cellulose is crashed by a grinder and left to dry for 24 hours;
- Roughly a third as much carbon disulfide is added to the bamboo alkali cellulose to sulfurize the compound causing it to jell;
- Any remaining carbon disulfide is removed by evaporation due to decompression and cellulose sodium xanthogenate is the result;
- A diluted solution of sodium hydroxide is added to the cellulose sodium xanthogenate dissolving it to create a viscose solution consisting of about 5% sodium hydroxide and 7% to 15% bamboo fiber cellulose.
- The viscose bamboo cellulose is forced through spinneret nozzles into a large container of a diluted sulfuric acid solution which hardens the viscose bamboo cellulose sodium xanthogenate and reconverts it to cellulose bamboo fiber threads which are spun into bamboo fiber yarns to be woven into reconstructed and regenerated bamboo fabric.
This gives some feel for how chemically intensive the hydrolysis-alkalization and multiphase bleaching manufacturing processes are for most bamboo fabrics that are promoted as being sustainable and eco-friendly.
The bottom line on bamboo. The manufacturing of bamboo into fabric raises environmental and health concerns because of the strong chemical solvents used to cook the bamboo plant into a viscose solution that is then reconstructed into cellulose fiber for weaving into yarn for fabric.
Bamboo clothing marketers have found a variety of ways to put the most eco-friendly and sustainable face on the manufacturing of bamboo fabric. The dominant manufacturing process of hydrolysis alkalization and multi-phase bleaching is generally referred to as a rather benign process utilizing caustic soda and bleach. The chemicals used are known to create a variety of health problems and neural disorders which can be hazardous to the health of fiber manufacturing workers. If the manufacturing facility lacks adequate pollution control systems – all too common in developing countries where regulations and enforcement are nearly non-existent – then these toxic chemicals can escape into the atmosphere through air vents and smokestacks and into waterways through inadequately treated waste water disposal systems.
Some bamboo fiber manufacturing facilities trumpet their sustainability and green credentials by establishing ISO 9000 Quality Management policies and ISO 14000 Environmental Management policies. This is largely a PR red herring tossed by the manufacturing facilities and marketers because these ISO standards do not mean that the facilities, their manufacturing processes or their fabrics have been certified by any of the international certification bodies such as SKAL, Soil Association, Demeter, KRAV, or OKO-tex.
excerp from a post by Michael Lackman of Lotus Organics
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Bamboo: in need of serious re-evaluation as a “Green Material”
It is surprising that the green building industry has overwhelmingly embraced bamboo products as being a viable green building material without any real attempts to determine and recognize the impacts created from the harvest, production and use of this material. This in spite of the ever increasing availability of production details and the current issues being raised concerning the environmental attributes attached to many construction materials in use today. Following are some revealing facts showing serious environmental issues associated with how bamboo is grown, harvested and processed into finished products, and the need to drastically change our views and the green status we have so quickly applied to bamboo products.
History, Distribution and Growth.
Bamboo has a very long history of being utilized in the construction of housing and other structures, boats, furniture and as a fuel. Over 1500 products are manufactured which incorporate bamboo as the primary raw material in their production, examples include fabrics, paper, musical instruments, crafts and utensils. The tender shoots of bamboo are also an important food source throughout Asia. Bamboo used in flooring and panel products for the North American market is primarily harvested in Hunan Province, China.
There are some 1200 varied species of bamboo which grow worldwide, covering over 22 million hectares in Asia, Africa and Central and South America. Approximately 80% of the worlds bamboo grows in China, India and Myanmar, China has an estimated 7.2 million hectares of bamboo with over half being plantation grown and the remainder growing within mixed natural forest. In India 10.5 million hectares of bamboo grows primarily interspersed in natural forests. Much of Vietnam is covered in bamboo due mainly through reforestation efforts to help curb erosion caused by chemical defoliants used during the war. In Europe there are as many as 300 species of temperate climate bamboos growing.
The two most notable qualities that bamboo possesses are its adaptability to a great variety of grow sites and its amazing growth rate. Documentation shows that it can grow from one foot to over three feet within a 24 hour period. A very diverse plant it can flourish in a wide variety of environments, in soils that are parched of nutrients and water to soils rich in minerals and moisture. Bamboo propagates by sending out shoots which in turn sprout and develop new growth. Once established this new growth, whether natural or replanted, will grow to full height within one year and reach maturity ready for harvest in four to seven years and in some cases up to ten years. A year after harvesting new shoots emerge and the natural regeneration starts again.
Economic Relevance
The demand globally for bamboo products is tremendous and continually growing, current trade estimates show bamboo at about $14 billion with a future of over $20 billion by 2015. Local and international markets for bamboo creates an income for more than 600 million people globally. 1999 figures showed that an estimated 5.6 million people in China work in the bamboo sector of which 4.5 million are farmers. In India where most bamboo comes from natural forests, initiatives are being introduced to greatly expand the bamboo industry. Several large companies are in place and producing flooring for the world market.
Environmental Impacts of Producing and Harvesting Bamboo.
As noted in the preceding dialog Bamboo has many positive attributes; rapid growth rate, renew-ability, wide global distribution, diverse utility and a sustainable livelihood for many, to name just a few. All these aspects are extensively used in advertising and media to promote bamboo as an environmentally desirable and socially responsible material. “ Is this the whole story?” Sadly: No
There is overwhelming documentation showing the negative environmental issues concerning harvesting and growing bamboo as noted by the Center for International Forestry Research (CIFOR), the Chinese Academy of Forestry, and the University of Madrid as noted below:
“Recently, bamboo expansion has come at the expense of natural forests, shrubs, and low- yield mixed plantations…It is common practice to cut down existing trees and replace them with bamboo.”
“As forest lands tend to be hilly and mountainous areas with steep slopes, clear cutting has resulted in an increase in erosion until bamboo becomes fully established…”
“Natural forest within the vicinity of bamboo plantations have sometimes given way to bamboo as a result of deliberate efforts to replace them or because of vigorous natural explosion of bamboo in logged over forests. This has also had a negative impact on biodiversity”
“The intensive management practices employed involve manual and chemical weeding and periodic tilling of the land to keep the soil clear of undergrowth. These practices increase erosion and result in single-species plantations over large areas”
“The intensive use of chemicals (pesticides, weed killers and fertilizers) [associated with growing bamboo] also affects the environment…”
These statements are reiterated in documentation of other researchers from the mid 1990s to the present.
Dr. J.T. Williams, Science Advisor to the International Network for Bamboo and Rattan writes:
“Although ecosystems modification or ecosystem conversion has over time resulted in short-term economic gains, these gains have often been obtained at the risk of long-lasting damage.”
“ bamboo resources are harvested in a non-sustainable manner.”
Dr. R.L. Banik, Bangladesh Forest Research Institute and Co-Chair, INBAR Working Group on Biodiversity writes:
"In the past, bamboo was a perpetual resource because of its vigorous vegetative regeneration. But at present, over-exploitation associated with growing human populations, destruction of tropical forests and new demands for industrial uses (especially by the pulp and paper industry) have resulted in wide-scale reduction of bamboo stocks.”
Dr. R. Roa, Principal Scientist at INBAR writes:
“ … serious constraints exist in the supply of bamboo and rattan. This is true in most countries where bamboo and /or rattan have been traditionally utilized. Since production is largely from natural forests, demand has outstripped the annual incremental production capacities of the forests.”
Dr. F. Maoyi, Chinese Academy of Forestry writes:
“ Many of the natural stands of bamboo in China are no longer truly natural regenerates since management has caused ecosystem conversion toward plantations.”
M. Monyrak, Department of Nature Conservation and Protection, Cambodia writes:
"Since commercially valuable bamboo resources are threatened by over exploitation, their availability in the natural forest is being reduced.”
There is a huge variance between the observations made by the research scientists working with bamboo and the literature propagated by commercial interests as well as a number of environmental organizations. Claims made that bamboo regenerates quickly and without the need for replanting are true, but conveniently avoid the reality that huge tracts of natural forest are being cleared to create a single species plantation. Another claim is that bamboo requires little or no fertilizer or pesticides to grow in light of the fact that in most cases both are used in substantial amounts to maintain growth yields as noted within promotional literature.
Striking similarities arise concerning the environmental issues with bamboo and those associated with the wood industry. Why is it that advocates of bamboo are not seeking certification for bamboo and the introduction of criteria, guidelines for sustainable harvesting and “ chain of custody monitoring’? It is ironic that the Green Building Council requires that wood must have FSC certification to accumulate points or be acknowledged as a green building material yet bamboo has no related requirement at all.
Bamboo is but one example of materials embraced by the “green movement” which are not given adequate evaluation before being accepted as truly viable “green” products.
This brief review notes only the facts pertaining to the growth and harvesting of bamboo, in a subsequent article the environmental concerns associated with the actual processing of bamboo to create such products as flooring, panelling and textiles will be discussed.
Compiled by Henry Krieger
Turn A New Leaf Inc.
References
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