Corn plastic or PLA (polylactic acid) cups, utensils, and packaging have been popping up everywhere and I have been curious how they stack up against conventional plastic. It seems obvious that plastic made from corn would be more eco-friendly right? I did a little research and compiled a list of PLAs green pros and cons.
- Manufactured from corn starch, a renewable resource.
- Biodegradable, breaks down into mostly carbon dioxide and water.
- Compostable, 6-12 months in a home composter (Many people are reporting that they will not compost in a home composter), 1-6 months in a commercial composter. Longer for heat resistant utensils. Once composted it is indistinguishable from the other compost.
- Does not emit toxic fumes if incinerated.
- Does not leech chemicals into food or soil.
- Freezer safe.
- Can handle hot items up to 120F (200F for utensils).
- Looks, feels, handles just like plastic.
- Is inexpensive.
- Is not recyclable, must be kept separate from plastic.
- Few commercial composting facilities (113 in U.S.), only 1/4 of which accept residential materials.
- Commercial Composters use Microbes to break down organic material. Large amounts of PLA in a composter would cause problems because it breaks down into lactic acid which is wetter and more acidic. They can break this down but it requires more oxygen for the microbes to consume. Commercial Facilities would have trouble providing enough oxygen for large amounts of PLA to breakdown. Anaerobic digesters would not have the same problem.
- It is estimated that in a landfill PLA will take anywhere from 100 to a 1000 years to biodegrade.
- Typically made from genetically modified corn and usually not organic.
- Diverting corn away from the world’s food supply.
To me the cons don’t seem too bad considering plastic can’t be composted, takes longer to decompose in a landfill (starts decomposing after around 700 years), and can leech chemicals into food and the soil. Overall I think PLA is a pretty good substitute for disposable plastic cups, utensils, and packaging. What do you think? Any more pros and cons?
edit: Lots of good comments made and a few saying that perhaps these are not as eco-friendly as their manufactures want you think. See comments for details..
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