| Project/Area Number |
18K04376
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 22040:Hydroengineering-related
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| Research Institution | Oita National College of Technology |
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Principal Investigator |
Higashino Makoto 大分工業高等専門学校, 都市・環境工学科, 准教授 (90311117)
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2021: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
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| Keywords | 浸透流 / 地盤内物質移動 / 地盤環境 / 雨量強度 / 塩分 / 地下水汚染 / 透水係数 / 物質移動 / 周辺地盤 / 塩化ナトリウム / 降水 / 水分保持曲線 / Darcy則 / 飽和・不飽和浸透流 / 降水の浸透 / 表流水・地下水 / 硝酸性窒素 / 施肥 / 凍結防止剤 / 不飽和地盤 / 塩分除去 / 豊浦砂 / 真砂土 |
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| Outline of Final Research Achievements |
Road salts such as sodium chloride (NaCl) are used in cold climate regions to increase road safety. These chemicals accumulate in soils near roads where road salt has been applied, and have the potential to cause environmental problems. Increases in the salt concentration of freshwater can degrade water quality and ecosystems. Mass transport and residence time of saline water from road salt applications in soil columns composed of Toyoura sand, weathered granite sand, and Andisols were investigated by simulations and in laboratory experiments. The presented model was found to match the experimental results for Toyoura sand quite well. Whereas, the model had difficulties in describing neither the experimental time variation of NaCl concentrations in the effluent nor salt mass left in the soil column for weathered granite sand and Andisols. This suggests that chemical processes have a significant effect on salt mass transport in the soil, and need to be further explored.
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| Academic Significance and Societal Importance of the Research Achievements |
寒冷地において，冬期に凍結防止剤として使用されたNaClの環境中への流出については，アメリカ合衆国，環境保護庁(EPA)が1988年に塩素イオンに関するガイドラインを策定している．他方，環境中に凍結防止剤由来と推定されるNaClが検出され，本格的に研究が行われるようになったのは2000年以降である．最近の研究結果によると，冬期に使用されたNaClの70%以上が地盤内に残存し，長期間に亘って環境に影響を及ぼし続けることが示唆されている．なお，国内においては，当該の課題に対して，学術的視点から殆ど検討は行われていない．凍結防止剤は我が国においても全国的に使用されており，本研究の社会的意義は大きい．
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