A little bit of searching and a couple of conversations with BC organic store owner reveal that it's really not that straightforward. Organic Clothing has an indepth look here but I'll try to summarize.
Bamboo has become so popular because of it's luxurious feel, affordability, ability to breathe and rate of moisture absorption. Bamboo is a fast growing grass that is (if done right) sustainable. It doesn't require barely any water or any pesticides at all! So what's the deal??
The process of changing bamboo grass fibers into clothing fibers can be, in short, extremely toxic. A TON of chemicals are typically used to process the poor grass and are causing health problems for Chinese factory workers (whom also have little fair trade or sustainable production protection from the Chinese government). These chemicals include caustic soda (one of the main ingredients in Drano) and lye.
Even though I said I'd summarize- I just thought I'd post the typical chemical steps for processing bamboo fibers using the hydrolysis alkalization with multi-phase bleaching technology:
- 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. (http://organicclothing.blogs.com/my_weblog/2007/09/bamboo-facts-be.html)
This I guess is basically the process to form rayon as well, just with a different base. Did you skim through that after the first bit of chemically stuff like I did? Yup. And I sweat in THAT?
The increase in popularity in bamboo has also spurred rainforests and farmlands to be cleared away for bamboo growth. Bamboo is also a monoculture (kinda like a weed) and not so keen on biodiversity and as a result not the most sustainable choice.
So what to do? How do you know that a company "farmed" bamboo sustainably? The article from Organic Clothing gives info on what each certification means and what to look for. Here is a snippet:
- ISO standardization is not credible and is more of a "greenwashing"- more on that in her article.
- Lyocell is a process that is much more environmentally friendly and has a 99.9% closed loop so all chemicals are processed and recycled. Lulu and Oqoqo have clothing
made from lyocell technology.
- Green Yarn is making "eco-fabric" with nano technology. Still iffy on how the bamboo is processed but lots of heat is involved and as a result- carbon. Also- these bamboo nano particles are woven into existing fabric- so their entire claim on sustainability would depend on the cotton/nylon etc's.
- the anti-bacterial properties of bamboo have been disputed quite a bit recently.
- look for third party certification while purchasing like Oeko-Tex
Wow- being environmentally friendly can get ridiculously complicated. But then, ignorance is not the answer. I'd much rather be aware of how clothing is made and who is suffering so I can wear my beautiful shirt than claim it's too complex to mentally process. I love the feel of bamboo fabrics but if I am to make a concious choice to buy a product based on sustainability than I need to be aware of the entire picture:
Global- it's the point of being Eco.