2023 Volume 19 Issue 3 Pages 106-116
In recent years, LCA methods for evaluating the reduction effects of environmental burdens by resource circulation of plastics are revisited, for which there seem the following reasons: （1） the simultaneous achievement of the decarbonization and the circular economy is required as the social background; （2） there remain undecided factors in the evaluation methods; and （3） the “production” perspective has recently been emphasized in addition to the “waste management” perspective in the assessment of resource circulation. As a consequence, we cannot avoid from discussion about the way how the reduction effect of burdens in the whole society should be attributed to the supply and demand sides of recycled materials. Even though a variety of approaches have been proposed for this purpose, it remains uncertain which approach should be applied to what kind of resource circulation. In this article, with the resource circulation of plastics in mind, LCA methods for evaluating and comparing cyclical use options including recycling are discussed. First, the cut-off and avoided burden approaches and approaches for attributing burdens and their reduction effects are graphically explained. Then, as remaining issues in the assessment of plastic resource circulation, those related to the choice of the evaluation approaches, selection of processes of which burdens are to be subtracted, and presentation of the effect of resource circulation are investigated.
