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Shinji Ueda Yoshihito Ohtsuka Kunio Kondo Shun'ichi Hisamatsu 《Journal of environmental radioactivity》2009,100(10):835-840
We investigated the vertical profiles of 239+240Pu, 137Cs, and excess 210Pb (210Pbex) in sediment core samples obtained from two freshwater lakes and two brackish lakes situated near the first commercial spent nuclear fuel reprocessing plant in Rokkasho, Japan, before the final test of the plant using actual spent nuclear fuel. The inventory of 239+240Pu in those lakes was larger than that in soil in Rokkasho, which indicated the inflow of 239+240Pu from the catchment area in addition to direct deposition on the lake surfaces. The 137Cs inventory in sediments of the brackish lakes was lower than that in the soil, which showed that part of the 137Cs was removed from the sediments by the brackish water or that it was not deposited into the sediments, because of the high solubility of Cs in brackish water. The 137Cs inventory in sediments of the freshwater lakes was higher than that of the brackish lakes, and comparable with that in soil except for one core sample out of four. The 239+240Pu/137Cs ratio in freshwater lake sediments was higher than that in soil, and that indicated that part of the 137Cs was lost from the sediments. The low inventory of 137Cs may be attributable to competition for absorption sites in sediments with ammonium ions formed in the reducing environment which occurs from summer to fall in the sediments. Those data will be used as background data on the artificial radionuclides in the lakes to assess the effect of released radionuclides on their concentrations. 相似文献
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David D. Parrish William C. Kuster Min Shao Yoko Yokouchi Yutaka Kondo Paul D. Goldan Joost A. de Gouw Makoto Koike Tomoko Shirai 《Atmospheric environment (Oxford, England : 1994)》2009,43(40):6435-6441
Ambient measurements of hydrocarbons, carbon monoxide and nitrogen oxides from three mega-cities (Beijing, Mexico City, Tokyo) are compared with similar measurements from US cities in the mid-1980s and the early 2000s. The common hydrocarbon pattern seen in all data sets suggests that emissions associated with gasoline-fueled vehicles dominate in all of these cities. This commonality suggests that it will be efficient and, ultimately, cost effective to proceed with vehicular emission controls in most emerging mega-cities, while proceeding with development of more locally appropriate air quality control strategies through emissions inventory development and ambient air monitoring. Over the three decades covered by the US data sets, the hydrocarbon emissions decreased by a significant factor (something like an order of magnitude), which is greater than suggested by emission inventories, particularly the EDGAR international inventory. The ambient hydrocarbon and CO concentrations reported for the three non-US mega-cities are higher than present US ambient concentrations, but lower than those observed in the 1980s in the US. The one exception to the preceding statement is the high concentrations of CO observed in Beijing, which apparently have a large regional contribution. 相似文献