Biodegradable plastic bags are not as eco-friendly as their labeling might suggest. A new study discovered that these biodegradable plastics can actually survive years in various environments without fully decomposing. Researchers examined different types of biodegradable plastic bags and found that they were still intact after spending three years in the ground, water and air environments. In fact, the bags were still able to carry groceries without tearing.

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The study was recently published in the Environmental Science and Technology journal. The scientists believe their research indicates that biodegradable plastic bags might not be a viable substitute for single-use plastics, because the rate of degradation is much longer than previously thought. Considering the growing concern surrounding plastic waste, the study could have significant impacts on the industry.

Related: A guide to the different types of plastic

“After three years, I was really amazed that any of the bags could still hold a load of shopping,” lead researcher Imogen Napper explained. “For biodegradable bags to be able to do that was the most surprising.”

person holding old biodegradable plastic bag stuffed with groceries

Researchers examined five types of plastic bags. This includes biodegradable, oxo-biodegradable, compostable and high-density polyethylene (conventional plastic) bags. The only bag that fully decomposed in marine environments was the compostable bag, which completely disappeared within three months.

The reason the compostable bags did not perform well in the other environments is that they are designed to break down in the presence of micro-organisms. If they are buried in soil that lacks these organisms, the bags will not break down properly.

person holding old biodegradable plastic bag stuffed with groceries

In light of the study, the company that makes the compostable bags, Vegware, issued a statement about how its bags will only decompose in the right environment, which is what the product was designed to do.

Based on the findings, experts believe the general public is being misled when it comes to biodegradable plastic bags and that companies should be required to change their labeling to reflect the reality of the situation.

+ Environmental Science & Technology

Via The Guardian

Images via Imogen Napper