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Just How Great Is Biodegradable Plastic?

By Larraine Roulston:

NOT GREAT! Plastic is not a natural product and, biodegradable or not, it still takes years to break down and the fragments then become micro-plastic. In the UK, researchers submerged and buried what claimed to be “compostable” and “biodegradable” single-use plastic bags and found that after 3 years, they were still able to fill these bags with groceries. Sadly, when our society realizes that a product becomes an environmental disaster, we feel compelled to replace it with another “convenience”labeled “eco-friendly.” Scientists are put to work seeking ways to make plastic less harmful — when, actually, biodegradable plastics still have to be manufactured and transported, therefore using fossil fuel. Political leaders waste time discussing the problem and arguing whether or not it should be banned. Personally, I learned that a corn starch based compostable chip bag took over 3 years to finally disappear in my compost heap.

Imogen Napper and her team of researchers from the University of Plymouth set out to discover how quickly plastic disintegrates. They tested five different types of bags commonly used in the UK. The film was regularly monitored and recorded for visible surface loss and disintegration. After nine months, the plastic that had been exposed to open air disintegrated into fragments. Napper, who worked on the project as part of her PhD, stated, “After three years, I was really amazed that any of the bags could still hold a load of shopping. For a biodegradable bag to be able to do that was the most surprising. When you see something labelled [sic] in that way, I think you automatically assume it will degrade more quickly than conventional bags. But, after three years at least, our research shows that might not be the case.”

In conclusion, the team wondered, “Can biodegradable formulations be relied upon to offer a sufficiently advanced rate of degradation to offer any realistic solution to the problem of plastic litter?” Head of the International Marine Litter Research Unit, Professor Richard Thompson OBE, who was also part of the project, said, “This research raises a number of questions about what the public might expect when they see something labelled [sic] as biodegradable. We demonstrate here that the materials tested did not present any consistent, reliable and relevant advantage in the context of marine litter. It concerns me that these novel materials also present challenges in recycling. Our study emphasizesthe need for standards relating to degradable materials, clearly outlining the appropriate disposal pathway and rates of degradation that can be expected.”


  • Those who utilize their community’s green bin organics collection or take advantage of the Molok system offered in some areas can fold newspaper into a bag to hold kitchen peelings. When the sturdy paper bags that contain flour, sugar and potatoes become empty, they too can serve to gather organics.
  • Take your own reusable cloth bags when shopping atall retail stores.
  • Small groups could easily ban disposable plastics. For example, book clubs could rule that members avoid bringing them to meetings. School principals have banned peanuts — why not include all single use-plastic bags also?

Today, many environmental challenges are facing us. Time to Re-think “convenience.”

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Larraine writes children’s illustrated adventure stories on composting and pollinating. To view, visit: www.castlecompost.com

About Larraine Roulston

A mother of 4 with 6 wonderful grandchildren, Larraine has been active in the environmental movement since the early l970s. When the first blue boxes for recycling were launched in her region, she began writing a local weekly newspaper column to promote the 3Rs. Since that time, she has been a freelance writer for several publications, including BioCycle magazine. As a composting advocate, Larraine authors children's adventure stories that combine composting facts with literature. Currently she is working on the 6th book of her Pee Wee at Castle Compost series, which can be viewed at www.castlecompost.com. As well, Larraine and her husband Pete have built a straw bale home and live in Ontario.

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