While new research from the University of Plymouth is being touted in the press as having found that “biodegradable” bags may not degrade any faster than traditional plastic bags, the Plant Based Products Council (PBPC) disputes the reports. The organization says that the bag used in the study to purportedly show that biodegradable bags do not always effectively degrade was not actually a biodegradable bag.
The recent study, conducted by scientists at the University of Plymouth and published by Environmental Science & Technology, found that after three years in dirt or water, the bags were still functional – and, in some cases, still able to carry five pounds of groceries (via Fast Company). But the bag used “was not a certified biodegradable bag and had never been marketed by the manufacturer as such,” says Mary Solecki, a spokesperson for the PBPC.
The study, and the methodology used, “does not support the leading conclusions reported in the press,” Solecki says. The PBPC agrees with the study authors that standardized definitions and use of terms like “biodegradable” and “compostable” are important.
”The study very appropriately called for expansion of America’s composting infrastructure,” she says. “to do so would support greater use of compostable materials that improve greenhouse emissions, municipal waste, water quality and soil health.”
The study examined biodegradable, oxo-biodegradable, compostable, and conventional plastic bag materials over a three-year period in three environments: open-air, buried in soil, and submersed in seawater, as well as in controlled laboratory conditions. The study found that, after nine months exposure in open air, all bag materials had disintegrated into fragments.