An effect factor approach for quantifying the entanglement impact on marine species of macroplastic debris within life cycle impact assessment

Abstract

Plastic waste from anthropogenic activities is accumulating in the marine environment and poses a threat to marine biodiversity. Nevertheless, tools to assess the potential ecosystem damage from plastic waste are currently lacking from sustainability assessment approaches, such as life cycle assessment (LCA) methodologies. However, despite incomplete knowledge of the environmental mechanisms involved, the LCA community (researchers and practitioners) is calling for methodological developments to close this gap. We present a preliminary effect factor (EF) for working towards including the impacts of entanglement in plastic waste on marine biodiversity in life cycle assessment (LCA).

Our preliminary EF modelling approach couples spatially-differentiated and taxon-specific estimates of the current fraction of species affected by entanglement with spatially-differentiated floating macroplastic density estimates. Our results indicate that the effect of macroplastic density on the fraction of species potential affected by entanglement is highest in areas with low estimated plastic density, most prominently the Southern Ocean and equatorial Pacific. However, in parameterising our approach, we discovered trade-offs between data source options, e.g. species coverage versus range extent accuracy. In addition, we identify knowledge gaps, e.g. defining species sensitivity effect thresholds to enable statistically relating pressure (density of floating marine macroplastic) with effect (the potentially affected fraction of species), and set out options for future methodological development for achieving quantification of an effect factor ready for incorporation in to a life cycle impact assessment modelling approach.