Friday, October 22, 2010

It's Not Easy Being Green

Polylactic acid (PLA) and other biodegradable and bio-based polymers certainly have an apparent advantage in "sustainability" and perception of "greeness", but a new report (Note:this link is to an open access summary and has a link to the original report which is accessable by subscription/pay-per-view) concludes there are a slew of disadvantages that need consideration as well.
"Biopolymers trumped the other plastics for biodegradability, low toxicity, and use of renewable resources, but the farming and chemical processing needed to produce them can devour energy and dump fertilizers and pesticides into the environment..."
In other words, when a life cycle analysis is completed, the picture changes. In particular, production of the various biopolymers requires the use of fertilizers and pesticides, extensive land use for farming, and then there is the chemical processing needed to convert the plants into the final plastic.

What really caught my eye is that the biopolymers were the largest contributors to ozone depletion.

Somehow I don't think that this report will be the hot topic in the environmental blogs this weekend.


Anonymous said...

I would like to read more on that site soon. BTW, rather nice design you have at this site, but what do you think about changing it once in a few months?

Anonymous said...

Yes, farming corn sucks in terms of energy use and pollution! But it seems besides the point as far as poly(lactic acid) goes, because corn fermentation is far from the best way to make lactic acid. As far as I can tell the only reason to use corn for lactic acid production is because we have a lot of it and the farming lobby is stronger than common sense. What really matters is the environmental lifetime of PLA, which is substantially shorter than comparable polyolefins.

John said...

A strong lobby does help, as witnessed by the recent approval of the FDA to allow for 15% ethanol in gasoline, up from the current 10%.

Apparently we have so much corn that we can burn it.