Methodology to address potential impacts of plastic emissions in life cycle assessment

Abstract

Purpose Products made of plastic often appear to have lower environmental impacts than alternatives. However, present life cycle assessments (LCA) do not consider possible risks caused by the emission of plastics into the environment. Following the precautionary principle, we propose characterization factors (CFs) for plastic emissions allowing to calculate impacts of plastic pollution measured in plastic pollution equivalents, based on plastics’ residence time in the environment. Methods and materials The method addresses the definition and quantification of plastic emissions in LCA and estimates their fate in the environment based on their persistence. According to our approach, the fate is mainly influenced by the environmental compartment the plastic is initially emitted to, its redistribution to other compartments, and its degradation speed. The latter depends on the polymer type’s specific surface degradation rate (SSDR), the emission’s shape, and its characteristic length. The SSDRs are derived from an extensive literature review. Since the data quality of the SSDR and redistribution rates varies, an uncertainty assessment is carried out based on the pedigree matrix approach. To quantify the fate factor (FF), we calculate the area below the degradation curve of an emission and call it residence time $${\tau }_{R}$$ τ R . Results and discussion The results of our research include degradation measurements (SSDRs) retrieved from literature, a surface-driven degradation model, redistribution patterns, FFs based on the residence time, and an uncertainty analysis of the suggested FFs. Depending on the applied time horizon, the values of the FFs range from near zero to values greater than 1000 for different polymer types, size classes, shapes, and initial compartments. Based on the comparison of the compartment-specific FFs with the total compartment-weighted FFs, the polymer types can be grouped into six clusters. The proposed FFs can be used as CFs which can be further developed by integrating the probability of the exposure of humans or organisms to the plastic emission (exposure factor) and for the impacts of plastics on species (effect factor). Conclusions The proposed methodology is intended to support (plastic) product designers, for example, regarding materials’ choice, and can serve as a first proxy to estimate potential risks caused by plastic emissions. Besides, the FFs can be used to develop new CFs, which can be linked to one or more existing impact categories, such as human toxicity or ecotoxicity, or new impact categories addressing, for example, potential risks caused by entanglement.

Life cycle assessment of MycoWorks’ Reishi™: the first low-carbon and biodegradable alternative leather

“…It should be noted that current LCAs do not account for potential risks and impacts from emissions of microand nano-plastics in the environment [22]. Therefore, further contemplation of other factors, such as biodegradability as presented in the introduction above, helps present a comprehensive environmental performance of Reishi ™ .…”

The capabilities and deficiencies of life cycle assessment to address the plastic problem

“…The Marine Impacts in LCA working group was formed to help coordinate and disseminate efforts to reduce this gap in LCA methods (Boulay et al, 2021). Multiple efforts to integrate marine litter impacts alongside more long-standing impact categories are ongoing and vary in levels of complexity and robustness (Civancik-Uslu et al, 2019;Saling et al, 2020;Boulay et al, 2021;Lavoie et al, 2021;Stefanini et al, 2021;Woods et al, 2021;Corella-Puertas et al, 2022;Maga et al, 2022;Tang et al, 2022). The purpose of this review is not to discuss or debate different impact assessment metrics for plastic waste, but instead to highlight differences in scientific viewpoints that are likely to continue to occur in the use of LCA for evaluating the plastic challenge, irrespective of the development of suitable LCA impact metrics for marine litter.…”

Generating environmental sampling and testing data for micro- and nanoplastics for use in life cycle impact assessment

“…The LCIA results can be further translated into the potential damages to main areas of protection, such as human health, ecosystem quality and natural resources. There are scientific papers that address parts of the impact assessment model that relates the emission of plastic to the environment into potential impacts or damage in LCIA ( Maga et al, 2022 ; Salieri et al, 2021 ; Woods et al, 2021 ). This work is under development, with many data gaps that researchers are working to fill in order to develop characterization factors (CFs).…”