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Resultados 181-190 de 198
Investigation on release of nitrogen and phosphorus from the sediments of different depth in Lake Suwa [Japan]
1987
Kono, Y. (Nagano-ken. Research Inst. for Health and Pollution (Japan)) | Terasawa, J. | Harada, T. | Nasu, Y. | Kugimoto, M.
For the purpose of determining the effect of dredging on nutrients releasing from the sediment at the bottom of Lake Suwa after some of its sediment has been dredged, an experiment was performed to find out how much ammonium and phosphate would release from different depths of the sediment. Lake Suwa's sediment contains a lot of nitrogen and phoshorus down to its lower layers. The results of the experiment were as follows: The speed at which ammonium released from was faster as the depth of sediment increased. The speed at which ammonium was generated in the sediment showed the highest of 2.58N micro g/g dry sediment d in a 0-10cm layer. However, ammonium showed a generation speed of 1.3-1.4N micro g/g dry sediment-d at the depth of 10cm and more, indicating that ammonium easy to release from is generated even in lower layers. The speed at which phosphorus released from was 1.3-1.7Pmg/square m d in a 0-20cm deep layer, and 0.14-0.31Pmg/square m d at the depth of 20cm and more. The speed of Phosphorus releasing from lower layers of the sediment decreased to 1/4-1/10 of that in upper layers, and it was indicated that very little phosphorus flows out of the sediment at the depth of 20cm and more.
Mostrar más [+] Menos [-]Survey of tsutsugamushi disease in Nagano prefecture during the period of 1981-1986
1987
Miyasaka, T. (Nagano-ken. Research Inst. for Health and Pollution (Japan)) | Muramatsu, K. | Wada, M. | Sasai, S. | Kobayashi, M.
Protection of public water supplies from ground-water contamination
1987
Pettyjohn, Wayne A.
Pollution physiology of estuarine organisms
1987
Vernberg, Winona B.
Physicochemical processes and wastes in the ocean
1987
O'Connor, Thomas P. | Burt, Wayne V. | Duedall, Iver W.
Biological processes and wastes in the ocean
1987
Capuzzo, Judith M. | Kester, Dana R.
White paper on the forest effects of air pollution
1987
Control of nonpoint source pollution in Virginia
1987
Cox, William E. (William Edward) | Herson-Jones, Lorraine M.
Monitoring of gaseous pollutants by tunable diode lasers
1987
Grisar, R.
Regional and long-range transport of air pollution
1987
Sandroni, S.