Identifying the Substance Flow of Metals Embedded in Japanese International Trade by Use of Waste Input-Output Material Flow Analysis (WIO-MFA) Model

This study proposes a method of combining a waste input–output material flow analysis (WIO-MFA) model with trade statistical data to identify the flows of substances embedded in trade commodities. We focused on the case of Japan as a typical processing and trading country, and we estimated each mass of iron and aluminum embedded in the imports and exports of 300 product items categorized in the WIO-MFA. We found that iron ore imported from Australia, Brazil, and India as a raw material is processed and exported to South Korea, China, and other Asian countries as steel materials and to the United States as steel materials and automobiles. Primary aluminum imported from Russia, Australia, and Brazil as a raw material is processed and exported to Asia as rolled materials and to the United States as rolled materials and automobiles.