Bioplastics: Benefits and Pitfalls (part 2 of 2)

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2019/12/17 Bioplastics: Benefits and Pitfalls (part 2 of 2)

Bioplastics: Benefits and Pitfalls
Source from: https://greenamerica.org/take-plastics-challenge/bioplastics-benefits-and-pitfalls

Recycling Bioplastics
Recycling bioplastics isn’t always an easy accomplishment. Recyclers fear that non-petroleum-based plastics will corrupt their streams (many bioplastics have lower heat resistance—and that whole biodegrading thing they might do is not desirable in the eyes of recycled plastics manufacturers for fear that the recycled plastic will degrade prematurely).
Most bioplastic manufacturers say recyclers’ concerns are unfounded. In fact, bioplastics are recyclable; bio-polyethylene (given a #4 resin recycling code) is even accepted in many traditional recycling streams. As for bioplastics PLA and PHA (the #7s), they are generally not accepted by municipal recycling collections, but some manufacturers offer to take back their products for recycling. However, there is no infrastructure for individuals to collect and transport the plastics back to the manufacturers, so for those unwilling to mail their bioplastics back to the manufacturer, in the trash it goes!
In essence, current US recycling and composting facilities just haven’t caught up with bioplastics. And in order to give recyclers and composters the incentive to start to invest in accepting bioplastics in their streams or facilities, there needs to be a significantly larger volume of bioplastics to recycle or compost. Basically, the problem has to get worse before it will get better. The current and predicted growth rate for the bioplastics industry (estimated to be upwards of 40% in the next four years by some experts, like Melissa Hockstad), might make that happen sooner than later.

The Toxicity Question
As we reported in the Nov/Dec 2011 Green American, plastics are rarely just made out of oil—they’re mixed with a host of chemical additives to enhance their capabilities, i.e. make them more flexible or less flammable, to prevent them from degrading or to tint them pretty colors, write Mike Neal and Dr. Anthony Andrady in a 2009 research paper published in the Royal Society’s Philosophical Transitions B. The same holds true for bioplastics—they aren’t just made from plants. They may have the same toxicity issues that a conventional plastic does.
In October 2010, a team from the University of Pittsburgh released an analysis of both petro- and corn-based PLA bio-plastics for toxicity and environmental life-cycle impact (from cradle to end use, not including disposal), published in Environmental Science and Technology. The bioplastics were more toxic than conventional plastics when it came to releasing ozone-depleting chemicals, carcinogens, acidification, eutrophication (contributing to dead zones in bodies of water, usually via fertilizer runoff) and eco-toxicity.
These impacts came largely from fertilizer and pesticide use associated with growing the corn feedstock for the bioplastics, say the researchers. And critics of the study note that it did not take bioplastics’ sustainability trump card—its ability to biodegrade or compost—into account at all in the lifecycle analyses, which may have put bioplastics far ahead of petro-plastics in more categories.
But analyzing the manufacturing of bio-based feedstock into plastics did contribute to the researchers’ toxicity rankings.
In addition to feedstocks, chemical additives and manufacturing processes will differ between manufacturers. Other, more responsible manufacturers not included in the University of Pittsburgh’s analysis have demonstrated far different results when it came to the toxicity of their products.
What consumers can learn from this study is that just because a plastic is plant-based doesn’t make it 100 percent nontoxic.

An Evolving Industry
Responsibly manufactured bioplastics make a lot of sense in many ways. At the most basic level, they aren’t derived from petroleum, and reducing dependence on oil is always a good thing. There’s no question that conventional plastics are an enormous problem for the environment on many levels, from their production to their disposal. Adding urgency to the matter are the expected continued growth of the use of plastics and dismal rate of plastics recycling. Secondly, based on the information we know now about bioplastics, they don’t stick around for hundreds of years, though they probably don’t degrade as quickly as most manufacturers claim—certainly not if they are in a landfill.
At this point, corn, sugar cane, or soy beans may not in sum be significantly better than petrochemicals as a source for plastics, but it’s a start. Bioplastics are still a new industry and it’s evolving almost daily. Nonprofit, watchdog groups (like BPI and SBC) are stepping in where state and federal laws and regulations lag, too. Companies that are using corn, even GM corn today, are already looking to other biomass to produce their bioplastics in the future.
Given enough pressure from consumers, environmental groups, and federal agencies on bioplastics manufacturers, recyclers, and composters to coordinate their efforts, improve accessibility, and become greener, we could end up with a truly biodegradable, compostable, recyclable bioplastic—and live happily ever after.

What to Look for in Bioplastics
In the meantime, the path of least impact is to use compostable bioplastics, especially if you’re able to compost them through a commercial composter or through trial and error in your own compost pile (remember it could take a long time to fully degrade). Heeral Bhalala of ILSR recommends seeking out bioplastics that meet as many of the following criteria as possible:
- Made from biomass, not a conventional plastic with biodegrading additives (e.g. BioGreen Bottles)
- Meets at least a SBC BioSpec Bronze level
- Meets ASTM (D6400 or D6868) or EN 13432 standards of compostability or displays BPI’s Compostable Label or Cedar Grove Approved logo (European companies Vinçotte and Din Certco also have compost labels)
- Made from as much biomass material as possible, preferably displays the USDA Certified Biobased Product label
- Made from GMO-free crops

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