2023 Fiscal Year Final Research Report

Development of environmental analysis methods based on tracability in water and organisms

Research Project

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Project/Area Number	18K19878
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 64:Environmental conservation measure and related fields
Research Institution	Kagawa University
Principal Investigator	Yamada Yoshihiro 香川大学, 農学部, 教授 (30297460)
Co-Investigator(Kenkyū-buntansha)	大森浩二愛媛大学, 社会共創学部, 教授 (10152258) 井上幹生愛媛大学, 理工学研究科(理学系), 教授 (10294787) 申基チョル総合地球環境学研究所, 研究基盤国際センター, 准教授 (50569283)
Project Period (FY)	2018-06-29 – 2024-03-31
Keywords	アンチモン / トレーサー / 西条平野 / 灌漑 / 地下水 / 水循環
Outline of Final Research Achievements	The water source of the Saijo Plain was quantified by using Sb, a geological substance, as a tracer. The surface water sources of the Saijo Plain are diverse, including Kamo River water, shallow groundwater, deep groundwater. The Sb concentration was different between these four sources. The highest concentration was over 10μg L－1 in shallow groundwater, the lowest concentration was ca. 0.2μg L－1 in deep groundwater. The contribution of the water origin in each waterway was determined by using the Sb concentration. The contribution of the Kamo River irrigation water was almost 100% in the upstream area, but the contribution of shallow groundwater exceeded 80% in the middle basin area. In the downstream area, the influence of the Kamo River irrigation water became smaller, and the contribution of deep groundwater was about 50%. We found that the deep groundwater discharged from domestic and agricultural wells into waterways is an important source of water in the Saijo Plain.
Free Research Field	水環境科学
Academic Significance and Societal Importance of the Research Achievements	集水域の地質的な偏りは、水に反映される。それを利用し、水循環の解析を行った。下流の平野域では、標高差が少なく、人為的な河道変更も加わることで、水動態の解析を行うことが難しい。この研究では、的確なトレーサーを選定することで、水循環解析の低労力・迅速化を行い、この地域の水文的データベースの充実に貢献した。気候変動は地域の水循環を大きく変えている。西条市でも地下水の塩水化が起こっており、それを防止するための水利用が求められている。水文情報の定量化は、持続可能な水利用のために不可欠であり、本研究はそのための手法を提供した。