Plastic is such a dirty word in the "ecosphere" but often so difficult to avoid in our everyday practice. It's just so durable and useful in how we function. A few years ago I heard of something called "bio-plastic" and was amazed. "Plastic" made from plant product that biodegrades?? What a fantastic idea! Now I can feel good about taking that iced-mocha to go in a bioplastic cup! However, just like everything, the more you look into the reality of bioplastic, the more complicated the truth.
First of all, exactly what is bioplastic anyway? The word "Bioplastic" itself is traditionally used to mean a plastic derived from a biological source and does NOT necessarily mean compostable or even biodegradable. Bioplastics can be derived from vegetable oil, pea starch or microbiota, and the most common; corn starch. There are different kinds of bioplastics- some are more durable than others (i.e. bioplastic bags vs planters). The more durable bioplastics generally tend to either be not compostable or more difficult to compost. Bioplastics are often considered more sustainable because they do not rely as heavily on petroleum and use potentially renewable sources (like potatoes). Here's a quick rundown of the different kinds of plastics:
1. Starch Based Plastics (50% of the bioplastic market)- where common starches (like corn starch) has flexibilisers and plasticisers added in order to increase thermo-processing. Common plasticisers in other plastics are phtalates... however bioplastics may use sorbital or glycerine.
2.Polylactide Acid Plastics (PLA); these are your ice-mocha transparant plastic containers most often produced from corn starch. The chemical process seems complex to my non-chemistry brain...
3. Poly-3-hydroxybutyrate (PHB); a polyester produced by certain bacteria processing glucose or starch and is biodegradable without residue.
4. Polyamide 11; derived from natural oils, is not biodegradable but considered more sustainable that conventional plastic. Used for pneumonic airbrake tubing, sports shoes, catheters etc. (catheters etc??.... lol).
5. Bio-derived polyethylene; derived from ethanol and is chemically and physically identical to non-bioderived polyethylene: it's not biodegradable but can be recycled. The difference: bio-derived polyethylene is not a petroleum product (like plastic shopping bags). (wiki)
Who knew that there were so many different bioplastic types out there?? Having all these options for more sustainable plastics is great but does choosing a bioplastic over a non-plastic truly make for a better "eco" choice?
Although more sustainable, plastics made from corn starch or other agricultural species still require energy to grow and process. The corn starch used for bioplastics is not usually organically grown corn, thus bioplastic made from corn continues to support an industry that uses pesticides and a lot of fossil fuel. Also, the majority of North American corn is in some way genetically modified and owned by Monsanto (a huge seed corporation and manufacturer of agent orange).
The most pressing issue with bioplastics is the definition of "compostable vs biodegradable". Just because something is said to be biodegradable does not mean that you can put it in your home and municipal compost bin. There are currently no true standards for use of the term "biodegradable" in the market. By definition, biodegradable is something that is able to be broken down by biological agents such as bacteria. However, many products will eventually break down when exposed to sunlight; key word: eventually. Some petrochemical plastics are even considered "biodegradable" as they do slowly breakdown!
Many bioplastics that we see in our everyday world (like the transparent iced-mocha containers) are of the PLA type and require intense heat and processing to "compost". In this sense, if I left one of those cups in my covered compost bin, not exposed to sunlight or the high levels of heat needed to biodegrade.... it would take a looooong time. The same applies to putting this bioplastic in with garbage destined for the landfill/dump. Wrapped in plastic bags without exposure to oxygen, water or sunlight these products will not biodegrade in any short period of time.
Ok, so you can't put these plastics into your home compost bin, but say you live in a city like I do where you have a municipal composting program. As I quickly discovered, there is no guarantee that your municipal program will be able to process these bioplastics either. Although many local coffee shops (Smiling Goat, Just Us!) offer "compostable" coffee to-go cups, Halifax does NOT currently have the facilities to process these bioplastics. Essentially, they are being thrown out into the landfills. These cups are still advertised by staff and signs at Just Us! as being compostable... even though when confronted employees sheepishly admit that this in fact isn't the case.
This also applies to something like Jo-Sha "biodegradable" yoga mat wipes, which would also require high energy/heat to actually compost. Just tossing the wipe into your compost bin won't actually allow the wipe to decompose. Also, Jo-Sha has other ingredients in their wipes, including parabens... Not something I'd want in my soil. Also, yoga mats made from TPE (thermoplastic elastomers) like Lululemon's or Halfmoon also claim to be "biodegradable" but cannot be placed into your compost bin. (for more info on exactly what TPE is made of check out my eco-mat post :) ).
Although technology is producing exciting, more sustainable alternatives to plastic, unfortunately "bioplastics" are still very misleading. Instead of hoping the bioplastic will compost, look into whether there is an industrial composting facility nearby. Be ready to expose your bioplastic to a lot of sunlight allowing it the months it may need to biodegrade in your yard. Or, simply try to use alternatives to plastic like glass that is easily recycled. A quick update on my "biodegradable" planters; within 12 hours of having soil and water they completely fell apart! Now I have no idea what to do with them...
Knowledge is power and the ability to make the best "eco" choice available :)