Research claims lower environmental impact for PE packaging over other materials

A recent assessment authored by representatives of Trayak Inc., ExxonMobil and the Michigan State University School of Packaging sought to evaluate the potential environmental impacts of replacing polyethylene (PE) packaging such as bags, films and containers with alternative materials that include paper, glass, aluminum and steel, and found that PE packaging can have an average life cycle global warming potential (GWP) savings of approximately 70 percent compared to a mix of commonly used packaging materials in the United States.

When comparing plastic packaging and alternative materials based on mineral resource use, fossil energy consumption and water scarcity, the researchers say plastic packaging generally was found to have lower impacts than the alternatives.

Their paper, “Polyethylene packaging and alternative materials in the United States: A life cycle assessment,” has been published in the journalScience of the Total Environment and provides insights into the potential for product elimination of material switching to yield unintended consequences for the environment. The research collaborators say their findings were critically reviewed by a panel of independent experts and determined to be compliant with standards set by the International Organization for Standardization—ISO 14040 and ISO 14044, the international standards for principles, requirements and guidelines for life cycle assessments.

“Life cycle assessments are valuable to understanding the environmental tradeoffs associated with product elimination or material switching,” says Mason, Ohio-based Trayak’s Elizabeth Avery, the paper’s lead author.

Rafael Auras, co-author and a professor at MSU’s School of Packaging, says, “Our results show that in many applications, plastics offer lower assessed potential environmental impacts in terms of global warming potential, mineral resource use, fossil energy consumption and water scarcity. As new and better data emerge, stakeholders and policymakers can make decisions that help deliver more sustainable outcomes across different stages of a product’s life cycle, including disposal and recycling.”

The assessment focuses on five packaging applications: collation shrink films, stretch films for pallet wraps, heavy-duty sacks, nonfood bottles and flexible food pouches. The researchers say these include examples of packaging used for dog food, shampoo, water bottles, cosmetics and other everyday products.

Among the report’s findings, researchers note that PE-based packaging used less fossil resources than alternatives in 14 of 19 product comparisons. In 16 of the 19 packaged product comparisons, PE yielded a lower GWP, water scarcity and mineral resource use.

“Notably, those instances where PE did not have the lowest impact were typically found when comparing lightweight paper alternatives that incorporated additional materials such as plastic liner,” Auras says. “These alternatives required the use of multiple materials to meet functional performance requirements, which could involve keeping a product stable or protecting against moisture.”

Avery adds that life cycle assessments are powerful tools to compare different materials, especially when considering different packaging applications.

“Our study examines a wide range of PE packaging applications and provides insights where there has not been a PE-specific study done before,” Avery says. “This is valuable because even within a broad material category, individual materials will have their own implications for material, manufacturing and end-of-life phases.”

The Researchers say they anticipate their findings will inform ongoing policy discussions, including United Nations negotiations on a global treaty aimed at addressing challenges associated with managing plastic scrap, as well as the review of solutions such as banning single-use plastics or establishing extended producer responsibility programs.