Plant-Based Plastics Not Necessarily Greener Than Oil-Based Relatives, Researchers Find

[n2doc]

ScienceDaily (Oct. 25, 2010) — An analysis of plant and petroleum-derived plastics by University of Pittsburgh researchers suggests that biopolymers are not necessarily better for the environment than their petroleum-based relatives, according to a report in Environmental Science & Technology. The Pitt team found that while biopolymers are the more eco-friendly material, traditional plastics can be less environmentally taxing to produce.

Biopolymers trumped the other plastics for biodegradability, low toxicity, and use of renewable resources. Nonetheless, the farming and chemical processing needed to produce them can devour energy and dump fertilizers and pesticides into the environment, wrote lead author Michaelangelo Tabone, who conducted the analysis as an undergraduate student in the lab of Amy Landis, a professor of civil and environmental engineering in Pitt's Swanson School of Engineering. Tabone and Landis worked with 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. The project was supported by the National Science Foundation.

The researchers examined 12 plastics -- seven petroleum-based polymers, four biopolymers, and one hybrid. The team first performed a life-cycle assessment (LCA) on each polymer's preproduction stage to gauge the environmental and health effects of the energy, raw materials, and chemicals used to create one ounce of plastic pellets. They then checked each plastic in its finished form against principles of green design, including biodegradability, energy efficiency, wastefulness, and toxicity.

Biopolymers were among the more prolific polluters on the path to production, the LCA revealed. The team attributed this to agricultural fertilizers and pesticides, extensive land use for farming, and the intense chemical processing needed to convert plants into plastic. All four biopolymers were the largest contributors to ozone depletion. The two tested forms of sugar-derived polymer -- standard polylactic acid (PLA-G) and the type manufactured by Minnesota-based NatureWorks (PLA-NW), the most common sugar-based plastic in the United States -- exhibited the maximum contribution to eutrophication, which occurs when overfertilized bodies of water can no longer support life. One type of the corn-based polyhydroyalkanoate, PHA-G, topped the acidification category. In addition, biopolymers exceeded most of the petroleum-based polymers for ecotoxicity and carcinogen emissions.

http://www.sciencedaily.com/releases/2010/10/101021104741.htm

[StandingInLeftField]

1. Oh, well. Back to clay, leather, metal, wood, stone...

[valerief]

2. So this report benefits the petroleum industry. nt