| Co-Investigator(Kenkyū-buntansha) |
YOH Muneoki Tokyo Univ. Agr. & Technol., Fac.Agr., Professor, 農学部, 助教授 (50260526)
TAKADA Hideshige Tokyo Univ. Agr. & Technol., Fac.Agr., Professor, 農学部, 助教授 (70187970)
DOKIYA Yukiko Tokyo Univ. Agr. & Technol., Fac.Agr., Professor, 農学部, 教授 (10011909)
UEDA Shingo Nihon Univ., College Bioresource Soi. Lecturer, 農学部, 講師 (40318390)
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| Research Abstract |
In order to study geochemical behavior of micro-constituents derived from combustion of fossil, fuels, samples of atomospheric deposition(wet and dry) ,aerosol, surface water and soil were collected at the small forest catchment areas in the suburb of Tokyo, Yamanashi, Tochigi and Nagano Prefectures.
Material cycles were studied at the watershed of Lake Meike, Nagano Pref. Alkalinity and electric conductivity in Lake Meike were very low, and therefore Lake Meike is considered to be sensitive ; to acid deposition. Similar studies were carried out at Lake Shibire, Yamanashi Pref., and it was estimated that a part of sulfate in atmospheric deposit were transported from northern areas and nitrate was mainly from southern urban areas.
Proportion of nitrate to non-sea salt sulfate in wet deposition was higher at the forest area in Tama Hill(1.1), than that of average value in Japan(0.35).
It was suggested that nitrogen saturation may occur, judging- from high nitrate concentration in surface running water, vertical profile of nitrate in soil and high leaching rate of nitrate from soil, at the forest catchment area in Tama Hill, Tokyo, where emission of dinitrogen oxide, greenhouse effect gas, was observed to be high, compared with other forest areas.
It was estimated from the measurement of stable sulfur isotope ratio( ^<34>S)of sulfate, sulfur dioxide emitted at the Asia continent is transported, oxidized to sulfate in the skies of Japan and then deposited to Japan island.
It was suggested that a part of polycyclic aromatic hydrocarbons(PAHs)derived from combussion of fossil fuels were trapped to wax layers of the leaf and or deposited on the surface of the leaf, and then supplied to the forest floor by rainfall.
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