2021 年 38 巻 2 号 p. 176-187
The 4th Fundamental Plan for Establishing a Sound Material-Cycle Society aims to achieve exhaustive resource use though the development of new methods and indicators considering all stages of material lifecycle. In this study, material flow and stock analysis of non-metallic mineral resources and its compilation to physical input output table are conducted for the period 1990 to 2015. Also, the results are applied to 6 material flow indicators to discuss the efficiency in each stage of lifecycle. According to the results, the amount of direct material input has decreased since 1990, while the amount of domestic processed output has relatively increased in recent years. It was also found the recovery rate of used products has been over 90% since 2003. This indicates the utilization of used materials has been consistently promoted although the amount of outflow from used products has increased. The difference between the amount of outflow from statistics and estimates implies that there is a certain amount of so-called missing stock such as obsolete stock and dissipated stock. These stocks could be great concern in terms of its impact on material use time and future waste generation.
