Comparative LCA of single-use food containers including potential impacts from marine plastics

Given the negative environmental impacts of mismanaged plastic litter, in 2019, 170 countries pledged to "significantly reduce” single-use plastic products by 2030 (unep.org). Contributing to this goal, in 2020, the Canadian government announced the upcoming ban of six types of single-use plastics, including takeaway food containers (canada.ca/en/environment-climate-change/news/2020/10). In this context, there is a growing market for alternatives to plastic products. Yet, the fact that the replacement products do not contain any plastic does not necessarily imply that they are less harmful to humans and the environment than single-use plastics. Therefore, it is important to assess and compare the environmental impact of single-use plastics and their alternatives.

Life cycle assessment (LCA) is a tool that is commonly used to assist environmental decision making since it allows to compare the environmental impacts of different products or processes. LCA studies cover a variety of impact categories, including global warming, water scarcity, freshwater ecotoxicity, and human toxicity, among many others. So far, LCA impact assessment models do not include potential impacts associated with plastic leaked into the environment. Addressing this shortcoming, the international working group MARILCA (MARine Impacts in LCA) coordinates harmonized research efforts among organizations across the globe, with the goal to integrate potential impacts of marine litter – especially plastic – into LCA (marilca.org). Within the MARILCA framework, this study combines the latest developments from the working group and integrates them for the first time together in a novel approach to include the end-of-life of plastic litter in LCA studies.

In this work, we use LCA to study and compare the potential environmental impacts of three takeaway food containers from cradle-to-grave: one single-use plastic (expanded polystyrene, produced in Ontario) and two compostable alternatives made from either bagasse (made in China) or wood pulp (produced in Québec). All food containers fulfill the same functional unit: “using one container to carry a meal for one person in the Greater Montreal area in 2021”. Two scenarios are studied:

Food delivery: containers delivered from the restaurant and used at home. Food court: containers taken and used in a food court. In this scenario, a reusable ceramic plate is also studied as an alternative to single-use containers. The results of this case study illustrate the complete environmental profile of food containers throughout their entire life cycle, including for the first time the potential impacts of marine plastic litter. Since the results will highlight which steps of the product life cycle are the most damaging ones, this can help to direct future efforts to improve the environmental performance of food containers. We expect to observe a trade-off between different environmental categories: whereas at the end-of-life compostable materials may be less harmful to aquatic species than single-use plastics, compostable alternatives may be more harmful in other environmental categories. Damage modeling on the main areas of protection (human health, ecosystem quality and resource depletion) will allow to clearly quantify these trade-offs and help to understand the consequences of replacing plastic food containers with other commercial alternatives.