| Project/Area Number |
16405039
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Boundary agriculture
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| Research Institution | The University of Kitakyushu |
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Principal Investigator |
HARAGUCHI Akira The University of Kitakyushu, Faculty of Environmental Engineering, Professor, 国際環境工学部, 教授 (50271630)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 2006: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 2005: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 2004: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Pyrite / Peat / Brown coal / Acid sulfate soil / South East Asis / Eastern German / River water chemistry / Plant fossil resource / ドイツ |
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| Research Abstract |
In order to estimate the range of area that is affected by the sulfuric acid pollution after pyrite oxidation, surface water chemistry of two rivers in peat swamp forests in Central Kalimantan, Indonesia was surveyed at 1.0-3.0 km intervals in September (dry season) and March (rainy season). Water discharged from canals into the main stream of the Sebangau River and the Kahayan River showed lower pH compared to the mainstream water of the rivers, implying sulfuric acid loading from the canal to the main stream of the rivers. The ratio of concentrations of sulfate ion/chloride ion, which was used as a parameter for estimating the contribution of pyritic sulfate to the river water chemistry, showed that the sulfuric acid loading from pyrite oxidation appeared from the river mouth up to 150 km upstream in both the rivers. Water of the mainstream of the rivers as well as water discharged from artificial canals into the mainstream in the rainy season showed much higher acidity and a higher ratio of sulfate ion/chloride ion than those in the dry season. This implies that the discharge of pyritic sulfate from peat swamp forests to the limnological system is much higher in the rainy (high water table) season than the dry (low water table) season. Water in the canal in the rainy season was found to be highly acidic (pH = 2.0-3.0). Pyrite oxidation after peatland development causes not only acidification of soil but also acidification of the limnological ecosystem. The same sulfuric acid pollution was found in brown coal mining area in eastern Germany. Redox reaction of Fe and S associated with reduced organic materials (e.g. peat) controls the redox status of Fe and S and the consequent proton dynamics in wetland system in eastern Germany. Highly acidic fresh water in the tropical area could be associated with peat deposition.
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