[H-CG25] Cultural Hydrology

[HCG25-P06] Changes in nitrogen pollution processes with the advancement of the Food system industries
–A case study of Yamanashi prefecture–

*Kota Kato¹, Hiroshi Takeda¹, Makoto Saiki², Kei Nishida³ (1.Graduate School of Medicine, Engineering and Agriculture, University of Yamanashi, 2.Research Institute for Humanity and Nature, 3.Interdisciplinary Centre for River Basin Environment, University of Yamanashi)

Keywords:Food system, Nitrogen pollution, Input-Output analysis

Since the Green Revolution, the anthropogenic production of reactive nitrogen (hereafter, nitrogen) has expanded food production and met the dietary needs of half the world's population. However, some of the nitrogen from the food system cause nitrogen pollution such as global warming, eutrophication, and PM2.5 pollution around the world. To explore the nitrogen pollution, nitrogen flow analysis has been conducted to identify the nitrogen emission processes within the food system. Previous studies have analyzed on a global scale to grasp the global nitrogen impact, and on a local scale to propose specific pollution measures considering regional characteristics within the food system. Local-scale nitrogen analyses have mostly focused on regions with active primary industries such as agriculture. However, it is thought that new processes of nitrogen pollution arise with the externalization of food, even in Japan, where the primary industry is declining. In Japan, where secondary and tertiary industries, such as the food processing industry, are developed, the per capita nitrogen waste amount is twice the global average. This suggests that new nitrogen pollution processes, thorough food loss and waste, are emerging due to the advancement of the food industry. However, previous nitrogen flow analyses have been limited to food production and consumption due to methodological constraints, failing to identify nitrogen flow and pollution processes in the advanced food industries.
Therefore, by incorporating Input-Output analysis into the existing nitrogen flow analysis method, it was considered possible to reproduce the nitrogen flow in the advanced food industries (food processing, food distribution, and food service). In this study, a nitrogen flow analysis combined with an Input-Output analysis was performed for the food system targeting Yamanashi Prefecture for the years 2005, 2011, and 2015, where public data exist. Specifically, analyzed with two objectives: firstly, to identify nitrogen pollution processes originating from food waste previously unidentifiable, and secondly, to analyze the impact of industrial expansion (here, nitrogen input into each industry) on the amount of nitrogen waste.