| Project/Area Number |
05680454
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | SETSUNAN UNIVERSITY (1995)
National Institute for Environmental Studies (1993-1994) |
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Principal Investigator |
EBISE Senichi SETSUNAN UNIVERSITY,FUCULTY OF ENGINEERING,PROFESSOR, 工学部, 教授 (80026260)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Takanobu NATIONAL,INSTITUTE FOR ENVIRONMENTAL STUDIES DIVISION OF WATER & SOIL ENVIRONMEN, 水土壌圏環境部, 主任研究員 (00184755)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | NITRATE ION / NITROGEN POLLUTION / PRECIPITATION / SOIL WATER / GROUNDWATER / RIVER WATER / LAKE WATER / INCREASING TREND |
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| Research Abstract |
The wet deposition load of nitrogen, especially nitrate ion, has been increasing in recent fifteen years and their annual loads became larger in proportion to the annual precipitation in the catchment area of Lake Kasumigaura. Because the large quantity of nitrogen fertilizers has applied to fields and paddy fields in the past 40 years, the soil layr in these fiels had stored the large amount of nitrogen as nitrate ion and have been dicharging to underground water and river water. The high concentration of nitrate ion dischages to river water by prompt subsurface runoff compornent of storm runoff. Thisphenomenon were confirmed by the observations of pollutant runoff in some rivers of the catchment area during many storm events. The high concentrationof nitrate ion in soil layr of agricultural land has been increasing its concentration in river water. The flowing load of nitogen from rivers into Lake Kasumigaura supplyied the most of input nutrients of the lake and governs the primary production by phytoplankton in the lake, especially the river mouth area. The inflowing nitrogen load from agricultural land to the lake had been one of main causes of the eutrophication in the lake. The rate of annual nitrogen load of a river water to the amount of precipitation in the catchment area was introduced as an index of pollutant load by human activities.
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