With plastic pollution being a substantial danger to ecosystems and human health, numerous solutions to reduce this sort of pollution include lowering plastic manufacturing, reducing plastic waste creation, and enhancing plastic material and product design.
Researchers, including those at the Woods Hole Oceanographic Institution, have developed a sustainability metric for the ecological design of plastic products, like cup-lids, that have break-down more quickly in the environment. Image Credit: Bryan D. James
Researchers have now created a sustainability score for the ecological design of plastic objects with minimal environmental persistence. According to a recent study headed by experts at the Woods Hole Oceanographic Institution (WHOI) and published in the journal ACS Sustainable Chemistry & Engineering, adhering to these criteria might yield significant environmental and societal advantages.
The study authors added, “While plastic pollution threatens ecosystems and human health, the use of plastic products continues to increase. Limiting its harm requires design strategies for plastic products informed by the threats that plastics pose to the environment. Thus, we developed a sustainability metric for the eco-design of plastic products with low environmental persistence and uncompromised performance.”
This method of designing single-use plastics can have a significant effect. According to study analyses, the environmental costs to society associated with the replacement of single-use coffee cup lids with alternative materials such as polyhydroxyalkanoates and cellulose diacetate might be hundreds of millions of dollars lower.
Since frameworks and data sets exist to predict the many environmental problems, including resource depletion and greenhouse gas emissions, products are often created with environmental sustainability in mind by balancing these trade-offs. This is generally achieved by favoring one type of plastic over another.
Nevertheless, environmental persistence—the duration of time a plastic item remains polluted in the environment—has not been taken into account or measured in any material selection framework to date, despite it being a major environmental problem.
What is important to determine is how can we design functional, sustainable, and benign materials, products, and processes that embody all of the principles of green materials engineering into the future world that we are going to live in. What are the next set of strategies and tools that engineers, product designers, and even the average consumer can use to make the best choices for the environment, while not having to sacrifice product performance?
Bryan James, Postdoc Investigator, Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution
To develop the sustainability metric, the researchers noted, “integrated the environmental degradation rate of plastic into established material selection strategies, deriving material indices for environmental persistence. Our analysis identifies the materials and their properties that deserve development, adoption, and investment to create functional and less environmentally impactful plastic products.”
It has been difficult to establish and execute a sustainability criterion for persistence due to insufficient data on the variety of plastics used in consumer items. The availability of enough data on the true rates of environmental deterioration of various plastic types has only lately allowed scientists to adequately evaluate and incorporate the various features of plastics into their designs.
With the use of this data, the researchers are now able to demonstrate that, although changing a product’s plastic material can lower costs and embodied greenhouse gas emissions, doing so could bring far larger benefits in terms of lowering environmental persistence and longevity. Polylactic acid, for instance, would be a wise choice if a product designer just took cost and greenhouse gas emissions into account.
This material, however, is still present in the ocean. In contrast, cellulose diacetate and polyhydroxyalkanoates can have fewer greenhouse gas emissions and do not linger in the ocean, even if they are now just slightly more expensive than polylactic acid.
Ninety-nine percent of the papers that have been published on plastic pollution tell us how bad it is. This paper is looking at the issue in a much more forward-thinking way, about how do you address a problem in a meaningful scientific way that's attainable, achievable, and economically viable.
Christopher M. Reddy, Senior Scientist, Woods Hole Oceanographic Institution
The researchers used the measure, for instance, to redesign coffee cup lids, a common single-use plastic item. Presently, billions of single-use coffee cup lids are used annually, making up around five percent of the plastic waste gathered by global coastal cleaning initiatives. Researchers assessed which of the three types of coffee cup lids now on the market (made of polylactic acid, polypropylene, and polystyrene) has the least negative environmental impact.
James noted, “Which is better: a lid that has a bit more greenhouse gas emissions but persists less in the environment or a lid that has fewer greenhouse gas emissions but will persist for a longer time? To answer this, we put a dollar value on both options in terms of cost to make the product and cost to the environment and ecosystem services. Simply making products that persist less by virtue of not being there, or going away faster, reduces that cost to society tremendously.”
Collin Ward, study co-author and associate scientist in WHOI’s Marine Chemistry & Geochemistry Department, added, “When you are charged with making a new coffee cup lid that needs to be sustainable and green, and you have to figure out which polymer is best for the environment, currently, green might take into consideration how much energy is used to make the plastic or how much greenhouse gases are emitted. But the current calculus for a designer does not consider what the lid’s persistence is. What Bryan has done with the development of this metric is groundbreaking.”
He further stated, “What is important about this study is that it helps shift the narrative away from defining the problem of plastic pollution to arriving at solutions to the problem. Plastics are extremely useful materials – they are not going anywhere anytime soon. But everyone agrees the amount of plastic leaking into the environment is a problem. The framework presented in this study represents an important first step towards solving this problem by designing materials that simultaneously meet the needs of consumers and do not persist if incidentally leaked into the environment.”
James pointed out that by using deliberate methods to create wise design choices, “scientists, engineers, and designers have an opportunity to make a significant impact in the plastic pollution crisis. The metrics and methods developed in this study can direct design decisions and research priorities to reach this goal.”
The Weston Howland Jr. Postdoctoral Scholarship provided funds for this study, which was sponsored by WHOI’s Postdoctoral Scholar Program. The WHOI Ocean Vision Fund 2030, The Seaver Institute, The US National Science Foundation, and The March Marine Initiative (a division of March Limited, Bermuda) through WHOI’s Marine Microplastics Innovation Accelerator program also contributed additional funds.
Journal Reference:
James, B. D., et. al. (2023) Minimizing the Environmental Impacts of Plastic Pollution through Ecodesign of Products with Low Environmental Persistence. ACS Sustainable Chemistry & Engineering. doi:10.1021/acssuschemeng.3c05534