Dynamics of ocean-origin organic matter and control limit of chemical oxygen demand in the Seto Inland Sea

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04273
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Osaka University
• Principal Investigator: Nakatani Yusuke 大阪大学, 大学院工学研究科, 准教授 (20635164)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 瀬戸内海 / 化学的酸素要求量 / 外洋起源有機物 / 数値シミュレーション

Outline of Final Research Achievements

In the Seto Inland Sea, the achievement rate of the environmental standard for chemical oxygen demand (COD) is low, and there is a need to clarify the cause of this low COD. In this study, a three-dimensional flow and water quality model was used to analyze the dynamics of organic matter of open-ocean origin in the Seto Inland Sea and to clarify its influence on the recent COD anomaly. As a result, it was found that the amount of oceanic COD that cannot be artificially controlled is up to 60% and at least 20% of the total COD in the Seto Inland Sea, and it is considered to be an amount that cannot be ignored in the water quality management of the Seto Inland Sea.

Free Research Field

環境水理学

Academic Significance and Societal Importance of the Research Achievements

本研究において，瀬戸内海における外洋起源有機物の動態を解明し，CODの制御可能性とその限界を定量的に示したことで，今後の水質管理方針の抜本的見直しに資する知見を得た．