Analysis of Radionuclide Releases from the Fukushima Dai-ichi Nuclear Power Plant Accident Part II     

Pascal Achim  Marguerite Monfort  Gilbert Le Petit  Philippe Gross  Guilhem Douysset  Thomas Taffary  Xavier Blanchard  Christophe Moulin 《Pure and Applied Geophysics》2014,171(3-5):645-667

The present part of the publication (Part II) deals with long range dispersion of radionuclides emitted into the atmosphere during the Fukushima Dai-ichi accident that occurred after the March 11, 2011 tsunami. The first part (Part I) is dedicated to the accident features relying on radionuclide detections performed by monitoring stations of the Comprehensive Nuclear Test Ban Treaty Organization network. In this study, the emissions of the three fission products Cs-137, I-131 and Xe-133 are investigated. Regarding Xe-133, the total release is estimated to be of the order of 6 × 10¹⁸ Bq emitted during the explosions of units 1, 2 and 3. The total source term estimated gives a fraction of core inventory of about 8 × 10¹⁸ Bq at the time of reactors shutdown. This result suggests that at least 80 % of the core inventory has been released into the atmosphere and indicates a broad meltdown of reactor cores. Total atmospheric releases of Cs-137 and I-131 aerosols are estimated to be 10¹⁶ and 10¹⁷ Bq, respectively. By neglecting gas/particulate conversion phenomena, the total release of I-131 (gas + aerosol) could be estimated to be 4 × 10¹⁷ Bq. Atmospheric transport simulations suggest that the main air emissions have occurred during the events of March 14, 2011 (UTC) and that no major release occurred after March 23. The radioactivity emitted into the atmosphere could represent 10 % of the Chernobyl accident releases for I-131 and Cs-137.  相似文献   

Petrology and thermobarometry of mafic granulites and migmatites from the Chafalote Metamorphic Suite: New insights into the Neoproterozoic P–T evolution of the Uruguayan—Sul-Rio-Grandense shield     

A.O.M.S. Gross  G.T.R. Droop  C.C. Porcher  L.A.D. Fernandes 《Precambrian Research》2009,170(3-4):157-174

This paper reports a study of the metamorphic evolution of pelitic, semi-pelitic migmatites and mafic granulites of the Chafalote Metamorphic Suite (CMS), Uruguay, which represents the southernmost exposures of high-grade metamorphic rocks in the Dom Feliciano Belt, Uruguain—Sul-Rio-Grandense shield, South America. This belt is one of the Brasiliano orogens that crop out along the Brazilian and Uruguayan Atlantic margin, and the CMS is one of several disconnected segments of supracrustal rock in a dominantly granitic terrain. Petrological evidence from CMS mafic granulites and semi-pelitic migmatites indicates four distinct metamorphic assemblages. The early prograde assemblage (M₁) is preserved only as inclusions in porphyroblasts of the peak-metamorphic (M₂) assemblage. Peak-metamorphism was followed by near-isothermal decompression (M₃), which resulted in symplectites and coronitic textures in the mafic granulites and compositional zoning of Ca in garnet (decreasing rimwards) and plagioclase (increasing rimwards) in the semi-pelitic migmatites. The retrograde metamorphic assemblage (M₄) is represented by hydration reaction textures replacing minerals of the M₂ and M₃ assemblages. Average P–T calculations using the program THERMOCALC and conventional thermobarometric methods yield peak-metamorphic (M₂) P–T conditions of 7–10 kbar and 830–950 °C, near-decompressional (M₃) P–T conditions of 4.8–5.5 kbar and 788–830 °C and M₄ retrograde P–T conditions of 3–6 kbar and 600–750 °C. The calculated P–T path for the CMS rocks is ‘clockwise’ and incorporates a near-isothermal decompression segment followed by minor cooling, consistent with a history of crustal thickening followed by extensional collapse at ca. 650–600 Ma. The metamorphism recorded by rocks of this crustal segment may be correlated with 650 Ma metamorphism in the Coastal Terrane of the Kaoko Belt in Namibia, being the first unequivocal match between South America and Africa provided by crystalline rocks south of the Congo Craton.  相似文献   

Sustainability of groundwater in Mali,West Africa     

Alexandra Lutz  James M. Thomas  Greg Pohll  Mamadou Keita  W. Alan McKay 《Environmental Geology》2009,58(7):1441-1450

The following paper describes the goals and some preliminary work in the Bani sustainability study, an ongoing project in Mali, West Africa. Rural communities in Mali are increasingly relying on hand-pumps, which tap groundwater resources, as a means of obtaining potable water. The long-term sustainable yield of groundwater resources is not known but can be evaluated in sustainability study. In 2005, a groundwater sustainability study was established along the Bani River of Mali. The Bani study collected groundwater levels that were used in a conceptual groundwater flow model—the Bani model—to develop an understanding of current aquifer conditions and to make limited predictions of sustainability under various future scenarios. The Bani model showed the climatic parameters of recharge (derived from precipitation) and evapotranspiration to influence simulated groundwater levels and groundwater volume available, while increased pumping rates, due to population growth, showed little effect. When considered in the context of the actual Bani sustainability study area, the change in groundwater levels resulting from climatic parameters may have negative implications, especially during several consecutive years of decreased precipitation, such as drought, or if downward trends anticipated for precipitation continue.  相似文献   

Spatial distribution of polyfluoroalkyl compounds in dab (Limanda limanda) bile fluids from Iceland and the North Sea     

Lutz Ahrens  Ralf Ebinghaus 《Marine pollution bulletin》2010,60(1):145-7973

The spatial distribution of polyfluoroalkyl compounds (PFCs) was investigated in dab (Limanda limanda) bile fluids collected from Iceland and the North Sea. Concentrations of various PFCs, including perfluorinated sulfonates (C₄-C₆, C₈ PFSAs), perfluorinated carboxylic acids (C₉-C₁₄ PFCAs) and n-methyl perfluorooctane sulfonamidoethanol (MeFOSE), were quantified. Perfluorooctane sulfonate (PFOS) was the predominant compound with highest concentrations along the Danish and German coast (mean 9.36 ng/g wet weight (ww)). Significantly lower PFOS concentrations were found at the other sampling stations in the North Sea and Iceland (p < 0.01, t-test). Conversely, the spatial distribution of the PFCAs in Iceland and the North Sea was more uniform. The most abundant PFCA was perfluorononanoic acid (PFNA), while the mean concentration decreased with increasing chain length from 4.7 ng/g ww for PFNA to 0.04 ng/g ww for perfluorotetradecanoic acid (PFTeDA). Overall, the different spatial distribution of PFCs indicates different origin of sources and different transportation mechanism.  相似文献   

Sampling soil water along the pF curve for δ2H and δ18O analysis     

Natalie Orlowski  Lutz Breuer 《水文研究》2020,34(25):4959-4972

Soil water stable isotopes are widely used across disciplines (e.g., hydrology, ecology, soil science, and biogeochemistry). However, the full potential of stables isotopes as a tool for characterizing the origin, flow path, transport processes and residence times of water in different eco-, hydro-, and geological compartments has not yet been exploited. This is mainly due to the large variety of different methods for pore water extraction. While recent work has shown that matric potential affects the equilibrium fractionation, little work has examined how different water retention characteristics might affect the sampled water isotopic composition. Here, we present a simple laboratory experiment with two well-studied standard soils differing in their physico-chemical properties (e.g., clayey loam and silty sand). Samples were sieved, oven-dried and spiked with water of known isotopic composition to full saturation. For investigating the effect of water retention characteristics on the extracted water isotopic composition, we used pressure extractors to sample isotopically labelled soil water along the pF curve. After pressure extraction, we further extracted the soil samples via cryogenic vacuum extraction. The null hypothesis guiding our work was that water held at different tensions shows the same isotopic composition. Our results showed that the sampled soil water differed isotopically from the introduced isotopic label over time and sequentially along the pF curve. Our and previous studies suggest caution in interpreting isotope results of extracted soil water and a need to better characterize processes that govern isotope fractionation with respect to soil water retention characteristics. In the future, knowledge about soil water retention characteristics with respect to soil water isotopic composition could be applied to predict soil water fractionation effects under natural and non-stationary conditions. In this regard, isotope retention characteristics as an analog to water retention characteristics have been proposed as a way forward since matric potential affects the equilibrium fractionation between the bound water and the water vapour.  相似文献   

The value of instream stable water isotope and nitrate concentration data for calibrating a travel time-based water quality model     

A. Borriero  A. Musolff  R. Kumar  J. H. Fleckenstein  S. R. Lutz  T. V. Nguyen 《水文研究》2024,38(5):e15154

  相似文献   

Seismic excitation of the polar motion, 1977–1993     

Benjamin Fong Chao  Richard S. Gross  Yan-Ben Han 《Pure and Applied Geophysics》1996,146(3-4):407-419

The mass redistribution in the earth as a result of an earthquake faulting changes the earth's inertia tensor, and hence its rotation. Using the complete formulae developed byChao andGross (1987) based on the normal mode theory, we calculated the earthquake-induced polar motion excitation for the largest 11,015 earthquakes that occurred during 1977.0–1993.6. The seismic excitations in this period are found to be two orders of magnitude below the detection threshold even with today's high precision earth rotation measurements. However, it was calculated that an earthquake of only one tenth the size of the great 1960 Chile event, if happened today, could be comfortably detected in polar motion observations. Furthermore, collectively these seismic excitations have a strong statistical tendency to nudge the pole towards 140°E, away from the actually observed polar drift direction. This non-random behavior, similarly found in other earthquake-induced changes in earth rotation and low-degree gravitational field byChao andGross (1987), manifests some geodynamic behavior yet to be explored.  相似文献   

Constraining a SHRIMP U-Pb age: micro-scale characterization of zircons from Saxonian Rotliegend rhyolites   总被引：7，自引：0，他引：7  

Lutz Nasdala  Jens Götze  Robert T. Pidgeon  Ulf Kempe  Thomas Seifert 《Contributions to Mineralogy and Petrology》1998,132(3):300-306

We present results of a detailed investigation of zircons from two rhyolites from St. Egidien and Chemnitz, Saxony, using a combination of microprobe techniques (SHRIMP ion probe, Raman microprobe, SEM: SE, BSE, and CL imaging). These rhyolites belong to the so-called “lower volcanics”, which is the older of two series of Late Variscan volcanic rocks occurring in the Saxonian Sub-Erzgebirge basin (Germany). The purpose of the present contribution is to demonstrate that detailed characterization of zircons, as provided by the different micro-techniques, facilitates soundest interpretation of geochronological data. The zircons (at most 40 to 80 m in size) show oscillatory growth zoning, with reversely correlated CL and BSE signal intensities. These zircons are interpreted to have grown during crystallization of the rhyolite because, apart from some cracking, they do not appear to have experienced any alteration since the time of their growth: The shapes of the zircons and their internal structures revealed by CL and BSE imaging appear to be magmatic, and neither annealing of the accumulated alpha-decay damage nor disturbance of the U-Pb system is observed. The SHRIMP ion probe measurements on the zircons gave a Permian ²⁰⁶Pb/²³⁸U age of 278 ± 5 Ma (95% confidence). The concordance of this age is supported by the correlation between the low degrees of metamictization (estimated from Raman parameters) and the accumulated alpha fluxes (calculated from SHRIMP data). The 278 Ma zircon age is interpreted to represent the age of the “lower rhyolites” series and, with that, the age of postkinematic Late Variscan volcanism in the Sub-Erzgebirge basin, which has been related to anorogenic extension and uplift as a result of intracontinental rifting. Because of genetic association of rhyolites in the Sub-Erzgebirge basin and Li-F granites and lamprophyres in the neighbouring Erzgebirge, the rhyolite age also indirectly contributes to the understanding of the geological history of the Erzgebirge. The 278 Ma age is the first absolute dating result for rhyolites from the Saxonian Sub-Erzgebirge basin. Received: 16 December 1997 / Accepted: 4 May 1998  相似文献   

Time-series temperature measurements at high-temperature hydrothermal vents, East Pacific Rise 9°49′–51′N: evidence for monitoring a crustal cracking event     

D.J Fornari  T Shank  K.L Von Damm  T.K.P Gregg  M Lilley  G Levai  A Bray  R.M Haymon  M.R Perfit  R Lutz 《Earth and Planetary Science Letters》1998,160(3-4):419-431

Temperature measurements of hydrothermal vent fluids provide an important indicator of the physical and chemical state of mid-ocean ridge crest hydrothermal and magmatic systems. Changes in vent fluid temperature and chemistry can have dramatic effects on biological communities that inhabit these unique ecosystems. In an attempt to understand temporal variability of ridge crest hydrothermal activity as it relates to geological processes at the ridge axis, six high-temperature hydrothermal vents on the East Pacific Rise crest between 9°49′N and 9°51′N were instrumented and sampled repeatedly during five years following a submarine volcanic eruption in 1991. Bio9 vent, located on the floor of the axial trough near 9°50.2′N, has the most complete record of fluid temperatures from 1991 to 1997, including a continuous temperature record of nearly three years (1994–1997). Bio9 vent fluids were 368°C in 1991, increased to an estimated temperature ≥388°C after a second volcanic event in 1992, and thereafter declined over the next 2 years reaching a temperature of 365°C in December 1993. Continuous temperature records and point measurements made by Alvin's thermocouple probe show Bio9 vent fluids were stable for 15 months at 365±1°C, until March 26, 1995. On March 26, an abrupt 7°C increase occurred over a period of eight days at this vent, and a maximum temperature of 372±1°C persisted for 14 days. The vent fluid cooled gradually over 3.5 months to 366±1°C, and for several months at the end of the recording period the temperature increased a few degrees. A continuous record of fluid temperature at this vent between November 1995 and November 1997 shows a 5±1°C increase for the two-year period. The abrupt temperature increase at Bio9 vent, and coincident changes in faunal community structure, and geochemistry of vent fluids from this area suggest that a crustal event occurred, either in the form of a cracking front in the crust or intrusion of a small dike. Based on the results of a microseismicity experiment conducted around the Bio9 vent in 1995 [Sohn et al., Trans. Am. Geophys. Union 78 (1997) F647; Sohn et al., Nature (in press)], and the identification of a small earthquake swarm which occurred on March 22, 1995 we conclude that the temperature anomaly measured at Bio9 four days following the swarm was caused by a cracking front penetrating into hot crustal rocks beneath the vent.  相似文献   

The influence of shock-waves on UV-emission-lines     

Lutz R. Elzner 《Solar physics》1975,45(1):93-103

If shock-waves are running outwards through the solar atmosphere, the variations of the intensity of optically thin UV-lines should reflect the variations in temperature and pressure of the shocks. In addition, the high fluid velocity produces Doppler shifts in the local line profiles. Assuming vertically propagating shockwaves with a period of 200 s, a procedure is specified for calculating the time-dependent line profile for a radial line of sight. The width of the shock pulse which characterizes the shape of the shock, is treated as a free parameter. Because the processes of ionization and recombination are out of equilibrium, the relative ion densities are obtained by solving the continuity equations. Results are presented for the O vi-resonance-line 1032 Å.  相似文献