Have we all been seduced by the bio-plastics industry to think that polylactic acid products (PLA) or similar bio-plastics are a greener choice than plastics? Personally, I am not crazy about either. I have my issues with bio-plastics as I indicated in my article about Re:newal water’s PLA bottle. And my loyal readers know how I feel about plastic. (Gesture, thumb’s down.)
Interesting enough a team from University of Pittsburg conducted their own life cycle analysis of plastic verus biopolymers (which includes PLA and PHA). What did they find? Plastic and PLA are neck and neck with their environmental footprint. But there is more to the story.
Say It Ain’t so!
I know. My mouth was wide open in disbelief when I read the article. The team consisted of Michaelangelo Tabone , an undergraduate English major in the School of Arts and Science(ENG, A&S ’10), Amy Landis, a professor of civil and environmental engineering in the Univeristy’s Swanson School of Engineering, James Cregg, an undergraduate chemistry student in Pitt’s School of Arts and Sciences, and Eric Beckman, codirector of Pitt’s Mascaro Center for Sustainable Innovation and the George M. Bevier Professor of Chemical and Petroleum Engineering in Pitt’s Swanson School.
They examined 12 different products: 7 petroleum based polymers, 4 bio-polymers and one hybrid in both their pre-production and finished forms. They did not analyze the products for their eventual use and disposal.
In the pre-production stage, the team examined the environmental and health effects of the energy, chemicals used, and raw material extracted to create one ounce of one pellet of either the plastic or bio-polymer. In the finished stage, they accessed the products’ green design, which included its biodegradability, energy efficiency, wastefulness and toxicity.
The Envelope, Please
In the pre-production stage, plastic trumped bio-polymers due to:
- bio-polymers’ intensive agriculture use, which includes the use of pesticides and fertilizer
- the intense chemicals processing needed to create the bio-polymer.
- All four biopolymers were the largest contributors to ozone depletion
- Two of the biopolymers, PLA-G (sugar derived) and PLA-W (NatureWorks’ product) contributing the most to eutrophication. In a nut shell, the article states, eutrophication occurs “when overfertilized bodies of water can no longer support life.”
- One of the PHA-G topped the acidification category
- Higher levels of eco-toxicity and carcinogen emissions
A crushing blow to the biopolymer industry. Talk about taking a bat and whacking the heck out of bio-plastics.
Clear Knock Out. Can Bio-Plastics Recover?
Kind of like Rocky in the last round, the biopolymers made a come back run and scored big time in the finishing evaluation. The biopolymers trumped plastic in the finishing process due to their keeping with green design, which included evaluations pertaining to biodegradability, energy efficiency, wastefulness, and toxicity. NatureWorks’ PLA was the winner in this evaluation.
So, who was in last place for both categories? B-PET (the petroleum-plant hybrid biopolyethylene terephthalate) since this lucky dog combined the ills of agriculture as well as the structural component of plastic.
Soap Opera Continues.
Note, the story is not over. Landis is completing a full life cycle analysis study to include the materials’ environmental impact throughout their use and eventual disposal. Who will be the winner and who will be the biggest loser?
Do you think the Bio Industry Sulked in the Corner?
What I love about these evaluations are the rebuttals from the “harmed” product. And did they come out swing? Heck, yeah. Bruce Dale, professor of chemical engineering and associate director of biobased technologies at Michigan State University critized the study.
He stated the team failed to take into account the use and eventual disposal in their analysis, which in his opinion made the life cycled analysis incomplete . So in essence, Dale termed their study as a “cradle to gate.” Furthermore, he stated that the team weighed each environmental factor equally, and then averaged their findings. This type of evaluation of mixing different impacts on the environment and public health goes against the International Standards Organization’s recommendations.
According to a Plastic News Article ,
“The research team admitted that it used “the average impact from the PLA scenarios … as substitutes for PHA’s impacts on human health, respiratory effects, ozone depletion, and ecotoxicity [because] no life cycle inventory data were available for PHA within the ecoinvent database.”
The world of plastics is pretty complex. Believe me, I am still learning. For all of you geeky chemical and plastic types, here are the difference between PHA and PLA. PHA is a polyhydroxyalkanoate, which is a “linear polyesters produced in nature by bacterial fermentation of sugar or lipids.” PLA is a” thermoplasticaliphatic polyester derived from renewable resources, such as corn starch in the United States, tapioca products roots, chips or starch mostly in Asia or sugarcanes in the rest of world.” [Hyperlinks removed. Source.]
Dale also criticized the team’s findings by stating,
“[a]nother huge flaw is that there wasn’t any data for PHAs for them to make estimates for the impact categories, so they assumed that PLA data was appropriate for PHA.”
“They didn’t compare any type of products,” said Steve Davies, global marketing director for NatureWorks LLC in Minnetonka, which manufactures PLA. “They just compared the resins and not specific products. It didn’t look at how a bioplastics product is used and how it is disposed and that’s essential to a life cycle analysis.”
Could the Bio-Plastic Industry do a Better Job?
Can the bio-plastic industry take some culpability here? Michael Griffin of Carnegie Mellon University stated in a recent Discovery News article that using cellulosic sources such as corn stalks, grasses, or woody plant parts would be a better alternative in creating the bio-plastics.
“If instead of using something like corn, you move to something like cellulosic, that immediately gets you a reduction of impact. A lot of these cellulosic feedstocks use fewer chemicals and you get higher yield,[.]”
When Landis’ team completes their final part of the life cycle analysis, will bio-plastics be validated or remain neck and neck with their worse nightmare? Plain old plastic.
- Thoughts about the analysis?
- What do you think the final outcome will be and why?
- Thoughts about bio-plastics? Love them. Hate them. Indifferent?
- Any better alternatives to plastic and bioplastics?