Thursday, September 24, 2009

Are biodegradable plastics the answer to the Pacific gyre?

Not long ago I posted here about a continent of plastic circulating in the Pacific gyre, and how slow degradation of some plastics may actually be releasing toxins. Since then a great deal of discussion has taken place as what might be possible solutions. Some have suggested biodegradable materials, including biodegradable plastics, while others suggest that just adds to the problem.

The American Chemistry Council (ACC), the primary organization for large chemicals manufacturers in the United States, including the plastics industry recently issued a press release entitled "Degradable Materials Hold Great Promise, But Not a Current "Solution" to Preventable Marine Litter." In it they first argue that it is all marine debris, not just plastics, that are the problem. The then note that there isn't any one easy answer, but that most agree that "recycling, coupled with tough litter abatement laws, well-run municipal waste management systems, and behavioral changes," are needed.

The idea of biodegradable plastics and other materials has been met with mixed reviews. In general these degrade into less harmful materials, and if fully biodegradable, into carbon dioxide and water. But as the ACC release notes, Keep Los Angeles Beautiful has suggested that the perception of biodegradability actually leads people to litter more, as they think the litter will "just go away."

Another concern is that "biodegradable" is often defined broadly to include plastics that break down into smaller particles but retain much of the original chemical composition. Small particles are mistaken by marine life as food and ingested, which presents both the risk of possible leaching of materials into the bloodstream but also the risk of blockage, which keeps animals from eating normal food, extracting nutrition, and eliminating waste. Another option are bioplastics, which are actually created from renewal biomass sources such as vegetable oil and corn starch (normal plastics are derived from petroleum based sources).

So the jury is still out on what to do, but clearly the process begins with each of us, including limiting our plastic (e.g., less bottles of water and soda), recycling, and not tossing out trash into the environment.

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