samedi 27 décembre 2008

"Biodegradable" is one of Packaging's Most Misused Terms

If I were to select the single most misused and misunderstood word used today in the packaging arena, I would have to say “biodegradable.” There is no better example of the latest hype than a stroll through the aisles of PACK EXPO International 2008. After polling vendors about biodegradability claims and what data substantiates these claims, it seems that the term, “biodegradable” should raise a greenwash warning flag, especially when applied to fossil fuel-based plastics.

Like the term “renewable,” there is a sense that use of the term, “biodegradable” communicates something inherently environmentally virtuous. Why so? Nature biodegrades some things pretty well: leaves, people and other bio-based materials—all current carbohydrates that microorganisms have evolved to recognize and eat as food, leaving behind nutrients, minerals and evolving heat and carbon dioxide. The situation is very different when we talk about synthetic, fossil fuel-based polymers that microbes don't necessarily recognize as food. Despite this, “biodegradable” is perceived as a positive word to consumers and there is widespread belief that “biodegradable” means that something disappears, according to an American Chemistry Council survey.

Even if we successfully engineer fossil fuel-based polymers to be truly biodegradable within a timeframe that is meaningful to consumers and composters, I still question the environmental benefit of taking a 100 million-year-old fossil fuel-based polymer that is non-renewable and adding it to a landfill to biodegrade. We live on a planet that is so oversaturated with respect to carbon that the last thing we need is to add more fossil carbon to the system. What we need to do is recognize plastics as a valuable material resource, and then collect and recover plastics much like they do in Europe.

We do an abysmal job of collecting and recovering plastic packaging in the U.S. According to the U.S. EPA, we currently landfill 90 percent of all fossil-fuel-based plastic packaging. Perhaps biodegradation is perceived as a benefit because there is a general misperception that it solves over-dependence on landfills. But this misperception comes from a widespread misunderstanding of landfills, compounded by the lack of a coherent, national strategy for post-consumer materials management. One of the most significant misperceptions is that landfills are big compost piles. They aren't.

Today, landfills are built and lined with heavy-gauge plastic to prevent any leaching of contaminants into the ground water. Once it's filled, a landfill is capped to prevent any moisture from entering.
Landfills are designed to entomb things, not to encourage biodegradation. Even if something is inherently biodegradable, such as paper, the moisture, oxygen and microbial conditions for biodegradation don't readily exist in a landfill. We find newspapers in them from decades ago that are still intact.

The exception to this general rule is wet organic materials, like food and yard trimmings, which comprise about 25 percent of all U.S. municipal solid waste. These materials do have a tendency to biodegrade in landfills, but in the oxygen-deprived conditions of a landfill, they emit methane, a gas with 23 times more greenhouse gas potency than carbon dioxide.

If we are going to encourage biodegradability in materials, we need composting facilities as a recovery system designed to manage the problem.

We would get significant environmental benefits if we removed readily biodegradable materials out of landfills. And we need to collect and recover valuable fossil-fuel-based materials, because they're nonrenewable, and our children might need them some day. This speaks to the need for a broad national strategy for materials recovery encompassing all materials, be it polymer recycling or an infrastructure for composting. As it stands, we're capitalizing on a lack of understanding by touting claims that don't hold up, given the reality of our infrastructure.

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