Even the Sustainable Packaging Coalition isn't buying biodegradability

By: 
December 30, 2015

Science appears to be taking the upper hand at the Sustainable Packaging Coalition (SPC). A paper, titled "The SPC Position Against Biodegradability Additives for Petroleum-Based Plastics," and an open forum webinar held on this topic on Dec. 16 are enlightening in this regard. It seems that SPC, which "takes a material-neutral, lifecycle-oriented approach to packaging sustainability with a goal of enabling and encouraging a more sustainable economy for all materials," has found in its studies—and concluded—that the use of "biodegradability additives for conventional petroleum-based plastics . . . do not offer any sustainability advantage and may actually result in more environmental harm. These additives should not be used," says SPC.

The formal position paper against the use of biodegradability additives in plastics explains that one of the problems is that the term biodegradability "suggests that nutrients will beneficially return to the environment at the material's end of life." Yet it is actually compostability that is the "superior and preferred indicator of a material's ability to result in nutrient renewal and reuse." Compostability is defined as a "material's ability to successfully undergo a managed process that controls biological decomposition and transformation into a stabilized organic matter within a specified period time."

Compostability, in other words, is a controlled (manmade or managed) process. "The characteristic of biodegradability in itself does not mean that the material will break down in a reasonable, useful amount of time, nor that it will result in any soil-enriching biomaterial." The term biodegradable is misleading, says the SPC position paper, because it causes consumers to assume that the plastic materials labeled as such will break down into useful bio-nutrients into the soil or water. "Petroleum-based plastics made with the currently available biodegradability additives do not break down in such a manner; to date, these additives have not enabled any plastics to become fully compostable," said SPC.

SPC stated that a major problem with biodegradability is its negative impact on recyclability, an optimum end-of-life scenario for petroleum-based plastics due to two inherent attributes that make recovery ideal: "Their high embodied energy content qualifies their value for controlled energy recovery, and their exceptional durability renders them ideal for recycling." Biodegradability additives, "by design, are intended to compromise that exceptional durability," and to date there is no "satisfactory evidence" that plastics with biodegradable additives will not interfere with the recycling stream. Additionally, says the SPC position paper, "petroleum-based plastics . . . are not bio-based, and the addition of biodegradability additives does not change that characteristic."

Another problem that SPC notes in its position paper is that most additives are "designed to fragment petroleum-based plastics into small pieces in order to make it sufficiently available to the microorganisms that perform biodegradation." While these micro pieces of plastic cannot be seen by the human eye, they contribute to the "environmental impact of micro-pollution." Hence, there is a problem with marketing biodegradable additives as being "less detrimental to the environment" because they may contribute to improper end-of-life disposal and pollution.

People love plastic for its usefulness and longevity; they just want it to disappear

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