著者

角皆 静男

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.37, no.1, pp.61-68, 2003-03-19 (Released:2017-01-12)

参考文献数

28

著者

松尾 禎士 山崎 一雄

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.9, no.1, pp.1-4, 1975-06-30 (Released:2016-11-08)

著者

西村 雅吉

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.12, no.2, pp.i-ii, 1978-12-30 (Released:2016-11-13)

著者

天知 誠吾

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.47, no.4, pp.209-219, 2013-12-31 (Released:2017-02-24)

被引用文献数

1

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Iodine is one of essential trace elements for humans and animals, and is a constituent of thyroid hormones thyroxine and triiodothyronine. Insufficient iodine in the diet can cause iodine deficiency disorders such as endemic goiter and cretinism. Iodine has one stable isotope, 127I, and several radioisotopes, including 129I and 131I. From a radioecological viewpoint, long-lived 129I is of great concern because it is one of the most persistent radionuclides released into the environment from nuclear facilities and nuclear weapon testing. Given its long half-life (15.7 million years), 129I is expected to behave like a stable isotope over long time periods and it may accumulate in the human thyroid gland. Therefore, it is important to understand geochemistry of iodine for accurate safety assessments of 129I. The predominant chemical forms of iodine in the environment are iodate (IO3-; oxidation state, +5), iodide (I-; oxidation state, -1), and organically bound iodine. Recent studies have demonstrated that chemical forms of iodine are influenced or regulated by environmental organisms, especially bacteria. In this review, bacterially catalyzed iodine chemistries, including volatilization, accumulation, oxidation, reduction, sorption, and reductive dehalogenation of iodine, are summarized.

著者

秋澤 紀克

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.56, no.4, pp.52-63, 2022-12-25 (Released:2022-12-25)

参考文献数

85

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The oceanic crust is in contact with sea water, and thus water is likely to penetrate downward into the solid earth. Meanwhile, the oceanic crust is a place where water is partitioned from the magma. Water that is incorporated into the oceanic crust as hydrous minerals is mainly 1. water in differentiated magma, 2. water released from subducted oceanic plate and supplied to magma via wedge mantle in the back-arc spreading system, and 3. sea water causing hydrothermal circulation. Here, I give an overview of behavior of the water partitioned from the magma into the lower oceanic crust, which is of particular difficulty to access, and the actual state of water is difficult to grasp. In addition, I present the deep-rooted hydrothermal circulation reaching to the lower oceanic crust.

著者

日高 洋

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.53, no.3, pp.77-90, 2019-09-25 (Released:2019-09-25)

参考文献数

57

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Nuclear reactions are one of major causes of isotopic variations of several elements in natural materials. The Oklo uranium ore in the Francevillian Basin at Republic of Gabon is known as a fossil of natural fission reactor, because large-scaled fission chain reactions spontaneously occurred in the ore two billion years ago. It is of major concern to characterize the properties of the nuclear reactors and to investigate the behavior of fission products in and around the reactors. In this paper, firstly, geological and physicochemical characteristics of the Oklo natural fission reactors and their implications for radioactive waste disposal are shown. In the second, isotopic variations of several elements observed in meteorites and lunar surface materials are reviewed from my previous studies. Spallation reactions and neutron capture reactions induced by the interaction of cosmic rays produce the isotopic variations of some elements in the surficial materials of solar planets without atmospheric layers. Neutron capture-produced isotopic shifts of 149Sm-150Sm and 157Gd-158Gd have been usefully applied to understand the cosmic-ray exposure histories of meteorites and lunar surface materials. Additionally, several elements of solar primitive materials like carbonaceous chondrites show isotopic variations affected from the input of nucleosynthetic components out of the early solar system. As one of examples, Ba isotopic variations found in chemical separates of the Murchison meteorite are shown.

著者

中口 譲 池田 善紀 濱屋 心 朝倉 知也

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.50, no.3, pp.227-241, 2016-09-25 (Released:2016-09-25)

参考文献数

23

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High pH values of 9.65 and 10.1 were observed in the Amano River, Osaka Prefecture in 2013 and 2015. On the other hand, the high pH values were not recorded in 2014. This basification was observed under conditions of high water temperature and high dissolved oxygen concentration. From the results of pH, dissolved oxygen, nitrate+nitrite, phosphate and total alkalinity, we confirmed that this basification might be due to decrease of carbon dioxide by photosynthesis in the Amano River. The changes of pH value in the river water might be affect the speciation of trace metals. Concentrations of dissolved species of aluminum, chromium and copper were increased with increase of pH value, while those of dissolved species of nickel and zinc were decreased with increase of pH value. From the positive correlation between the relative fluorescent intensity of dissolved organic matter and the concentrations of nickel and zinc we confirmed that these elements might be dissolved as metal-fulvic acid complex within the observed pH range.

著者

相澤 省一

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.43, no.2, pp.59-71, 2009-06-25 (Released:2017-02-06)

参考文献数

47

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Trace amounts of Cd, Ni and Cu in Permian, Carboniferous and Silurian limestone samples from South Kitakami Terrane were determined by flame atomic absorption spectrophotometry combined with the ammonium pyrrolidinedithiocarbamate (APDC) -4-methyl-2-pentanone solvent extraction system. The geometric means of Cd contents of these limestone samples from Kusayamizawa (n = 9, Silurian), Onimaru (n = 5, Early Carboniferous), Roukando Cave (n = 5, Carboniferous), Nagaiwa Mine (n = 12, Early Permian) and Iwaizaki Coast (n = 12, Middle Permian) were 0.04, 0.31, 0.78, 0.32 and 0.43 ppm, respectively. The Cd contents of Permian and Carboniferous limestones tend to be relatively higher than those of the other geological ages (i.e., before Devonian and after Triassic). Most of the Cd in Permian and Carboniferous limestone samples can be dissolved with 1 mol dm-3 acetic acid, suggesting that a large portion of Cd2+ is incorporated from marine waters into calcite by replacing Ca2+ during the formation and deposition of precursory carbonate minerals of the limestones. The high Cd contents of Permian and Carboniferous limestones are independent of sedimentary environments in the ocean, such as distance from continents, which controls the amounts of land originated detrital materials. This fact implies that the concentration of Cd was high in worldwide throughout the ocean during Parmian and Carboniferous periods.

著者

三浦 輝 栗原 雄一 高橋 嘉夫

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.55, no.4, pp.122-131, 2021-12-25 (Released:2021-12-25)

参考文献数

49

被引用文献数

1

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Radiocesium-bearing microparticles (CsMPs),glassy water-resistant particles with highly concentrated radiocesium, were emitted by the Fukushima Daiichi Nuclear Power Plant accident. Since first discovery of CsMPs, a number of studies have analyzed the particles isolated from environmental samples and revealed their physical and chemical properties, distribution, and migration. This paper is intended to provide an overview focusing on the environmental transport and impact of CsMPs. First, we begin by reviewing the relationship between deposition areas and atmospheric plumes of CsMPs found on land. Next, search and separation methods for CsMPs will be described. Then, secondary transport via rivers and effect of CsMPs on Kd values of Cs in rivers will be discussed. Finally, CsMPs found in the ocean and their difference from terrestrial ones will be summarized.

著者

小畑 元 黄 国宏

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.56, no.3, pp.33-46, 2022-09-25 (Released:2022-09-25)

参考文献数

98

---

Trace metals, like iron, copper, zinc and cobalt, in seawater are essential for phytoplankton growth and limit the primary production in some oceanic regions. It is crucial to reveal not only distributions of the metals but also their chemical speciation in seawater because their availability to phytoplankton depends on their speciation. At present, it is well known that more than 99% of iron and copper are complexed with organic ligands in seawater, which was revealed mainly by using voltammetry. In this review, we introduce the electroanalytical methods of organic ligands for trace metals in seawater. Moreover, we indicate the voltammetric methods to determine nanomolar levels of specific organic ligands for trace metals, such as humic substances and thiols, in seawater.

著者

堀 真子

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.49, no.3, pp.115-129, 2015-09-25 (Released:2015-09-25)

参考文献数

75

---

Terrestrial carbonates, such as tufas and stalagmites, are unique archives in terms of providing paleo-environmental information of land area, especially in mid-latitudes where records of ice cores and corals are absent. The oxygen and carbon stable isotopic values (δ18O and δ13C) are the most fundamental proxy records, which reflect relative changes in hydrological condition and vegetation, respectively. The recent challenge focuses mainly on how we quantitatively estimate temperature, precipitation and geochemical circulation in the past. Here, I first review the traditional δ18O studies using tufas and stalagmites, and then introduce my challenge to evaluate multiple carbon sources in karst aquifer. Finally, I extended the mixing and partitioning model to the multi-tracers, such as Sr/Ca and REE/Ca ratios. Multi-tracer analysis is one of solutions to understand details of a unique karst system, which is involved by complex geochemical circulation and associated paleo-environmental changes in the catchment area.

著者

岩崎 晋弥

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.48, no.4, pp.319-335, 2014-12-25 (Released:2015-01-06)

参考文献数

80

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The Antarctic ice core records revealed atmospheric CO2 concentrations (pCO2) during glacial periods were ~80 ppm lower than those of interglacial periods. The mechanism of understanding the low atmospheric pCO2 of glacial periods is one of the most important problems in the global carbon cycle study. Most of paleoclimatologists consider that the deep-sea must have been an active pool of global carbon cycle on this timescale. However, there is no broadly accepted evidence that the deep sea played a role as the effective carbon pool during glacial periods. The reconstruction of deep-sea carbonate chemistry that is provided by oceanic CaCO3 cycle (CaCO3 preservation and dissolution) with glacial-interglacial cycles is a key to solve the mechanism of ocean carbon cycle. Number of previous studies reconstructed the pattern of CaCO3 dissolution on the seafloor during glacial-interglacial periods. These previous studies employed dissolution intensity proxies based on carbonate microfossils preserved in sediments. However, existing proxies are insufficient in order to obtain quantitative data for ocean carbon budget. This is due to the low accuracy of existing dissolution proxies and the lack of knowledge about carbonate dissolution mechanism. This review paper summarizes the principles, characteristics, application to paleoceanography and problems of carbonate dissolution proxies, and then discusses future possible development.

著者

阪上 正信

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.16, no.2, pp.vii-xii, 1982-12-30 (Released:2016-11-21)

著者

赤岩 英夫 田島 栄作 相沢 省一

出版者

日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.12, no.1, pp.1-4, 1978

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The bromine and iodine contents were determined simultaneously by neutron activation analysis on two boreholes of the Tertiary marine siltstones and marine tuffs collected from Tomioka, southwestern Gunma Prefecture, and the relationship between these elemental contents and the organic carbon content was investigated. The arithmetic means of the bromine and iodine contents of siltstone samples were 1.9ppm and 2.0ppm, respectively. Tuff samples gave averages of 0.69ppm for the bromine content and 0.75ppm for the iodine content. The positive correlations were observed between the halogen contents and the organic carbon content of the sedimentary rocks analyzed. This suggests that the bromine and iodine in the sedimentary rocks originate from marine plants and microorganisms incorporated during sedimentary processes.

著者

東 久美子

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.53, no.4, pp.133-148, 2019-12-25 (Released:2019-12-25)

参考文献数

97

被引用文献数

1

---

Due to global warming, the Arctic has been changing drastically and rapidly. The changes in the Arctic cryosphere affect not only the Arctic climate and environment but also the global climate system. There is an urgent need to improve the projections of future Arctic climate and environment, including mass loss of the Greenland ice sheet, which affects the global sea level, ocean circulation and global climate. To achieve these goals, we need to advance ice sheet and climate modeling. Long-term records of the past Arctic warmings and their impacts, and the understanding of the mechanisms are necessary. Arctic ice cores have been providing us with valuable information on different time-scales from decadal to orbital time-scales. For example, deep ice cores from Greenland have revealed abrupt warming events in the glacial and deglacial periods and their links to global environmental changes. Multiple ice cores from the Arctic have been used to reconstruct the elevations of the past Greenland ice sheet. Shallow ice cores from circum-Arctic ice caps and Greenland have shown anthropogenic increases of acids, toxic metals etc. after the industrial revolution. This paper briefly reviews the history of ice core studies in the Arctic and discusses future prospects.

著者

森 康則 井上 源喜

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.55, no.2, pp.43-56, 2021-06-25 (Released:2021-06-25)

参考文献数

24

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This paper outlines the usage and background of hot springs in Japan, known as “ONSEN” in Japanese, focusing on the regulatory science approach, and summarizes the definition and development systems of hot springs based on the Hot Springs Law. In accordance with this law, all prefectures receive an annual report on usage status from hot spring companies, which is converted into data by Japan’s Ministry of the Environment. According to the data, hot spring development peaked around FY2006–2007. Since then, the total number of hot springs has leveled off, albeit with a decreasing trend first, and currently a stable trend. In addition, the regional characteristics of volcanic regions such as the Kyushu and Okinawa regions, and non-volcanic regions such as the Kinki, Chugoku, and Shikoku regions, are reflected in the temperatures of the springs and artesian hot spring rates. Unlike other countries where geochemical samples are usually extremely difficult to obtain, Japan’s unique environment makes geochemical samples easily and continuously available. Therefore, Japan can be considered to be an extremely attractive research field for geochemists. However, it is necessary to exercise caution, because the development of hot springs involves not only geological and geochemical natural conditions, but also factors, such as economic conditions and population density.

著者

佐藤 圭 田中 友里愛 李 紅 小川 志保 畠山 史郎

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.41, no.4, pp.145-153, 2007

参考文献数

26

被引用文献数

2

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To study long-range transport of organic aerosols from East Asian countries to the East China Sea, 3- to 7-ring parental polycyclic aromatic hydrocarbons (PAHs) in aerosols collected at Cape Hedo, Okinawa, Japan (128.3°E, 26.9°N) during 2005-2006 were analyzed by high performance liquid chromatography. The total PAH concentrations were 0.00-16.0 (av. 1.22) ng m^-3 during the entire period. The seasonal average of total PAH concentration increased between winter and spring and decreased in summer. It is interpreted that the pollutants are transported to Cape Hedo by the monsoons from the Asian Continent between winter and spring, whereas oceanic air mass is transported by the monsoons from the Pacific in summer. The benzo[a]pyrene to benzo[e]pyrene ratios were 0.23-0.98 (av. 0.48) in winter and were lower than that measured in East Asian cities, showing that PAHs observed at Cape Hedo are aged by the photochemical reactions proceeding during long-range transport. The average total PAH level measured at Cape Hedo was only 1/10-1/20 of those measured in Japanese cities, but a total PAH level comparable with the average levels in Japanese cities was recorded during a long-range transport event in March, 2006.

著者

角皆 潤

出版者

日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.52, no.3, pp.107-129, 2018

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By using the hydrogen isotope exchange equilibrium between molecular hydrogen (H2) and water vapor, a new method called HIReTS (Hydrogen Isotopes Remote Temperature Sensing) was proposed for remote sensing of fumarole outlet temperatures. In this method, the hydrogen isotopic composition (D) of fumarolic H2 is obtained remotely from observation in a volcanic plume, and the outlet temperature is then derived from the obtained D of fumarolic H2. The HIReTS method can be used to obtain the fumarolic temperature remotely in active volcanoes when the actual fumaroles are inaccessible. Recent advances in using the 17O-excess (Δ17O) of nitrate were summarized as well. Within the possible sources of nitrate in the natural environment, only atmospheric nitrate that is produced from atmospheric NO through photochemical reactions can be characterized by the anomalous enrichment in 17O, reflecting the transfer of an oxygen atom from ozone. In addition, Δ17O is stable during partial metabolism̶such as denitrification and assimilation, so by using these characteristics of Δ17O, the author and coworkers were able to trace the fate of atmospheric nitrate deposited onto surface ecosystems. This also allowed the author and co-workers to propose a new method to quantify nitrate dynamics̶production rate through nitrification and metabolic rate through assimilation and denitrification̶in aquatic environments, using the Δ17O of nitrate. The Δ17O method is considered to offer an alternative to the traditional artificial tracer techniques for the determination of nitrate dynamics, including temporal variations.

著者

高橋 嘉夫

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.52, no.1, pp.1-28, 2018-03-25 (Released:2018-03-25)

参考文献数

131

被引用文献数

2

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Geochemical and environmental-chemical studies based on speciation mainly using X-ray absorption fine structure (XAFS) spectroscopy by the author have been reviewed in this manuscript. These studies revealed that we could understand physico-chemical processes behind the distribution and isotopic data obtained in various geochemical studies by this approach, which can be called as molecular geochemistry. This approach allows us to interpret geochemical cycles of various elements from atomic and molecular scale levels, which in turn enables us (i) to extract more information from geochemical data related to earth history and (ii) to predict environment in future more accurately. The studies introduced here include environmental chemistry of rare earth elements and actinides, behavior of toxic elements at earth surface, environmental impacts of speciation of various elements in aerosols, enrichment of various elements to ferromanganese oxides and its application to paleo-environment studies, understanding of isotope fractionation based on speciation data, and migration of radioactive nuclides emitted by the Fukushima Dai-ichi Nuclear Power Plant accident. It was also shown that development of X-ray spectroscopic methods applied to geochemistry and environmental chemistry has opened new fields in environmental geochemistry and trace element geochemistry. Through these various topics, I would like to emphasize that systematic studies on behavior of various elements in environment in terms of physico-chemical viewpoint can provide various new ideas in wide fields in geochemistry as was suggested by Prof. V. M. Goldschmidt. The basic knowledge of various elements can be a firm basis to use geochemistry to obtain more general information in earth and environmental sciences. The attractiveness and importance of molecular geochemistry indicated in this manuscript suggests that this field can be one of drivers to develop new geochemistry in 21st century.

著者

野口 高明 今栄 直也

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.32, no.4, pp.175-184, 1998-12-15 (Released:2016-12-26)

参考文献数

53

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Extraterrestorial materials are divided into two categories based on their sizes: meteorites are >1mm across, and cosmic dusts<1mm across. Because most of cosmic dusts experienced severe heating during atmospheric entry, they were melted or hydrous minerals in them were decomposed into the aggregates of anhydrous minerals. However, some cosmic dusts keep original mineralogy and petrology before atmospheric entry, due to lower peak temperatures during the entry. Mineralogy and petrology, as well as chemistry, of such cosmic dusts (many interplanetary dust particles (IDPs) and some micrometeorites) are different from those of meteorites. Therefore, it is clear that such cosmic dusts are different in origin from meteorites. Parent bodies of some pyroxene-class anhydrous IDPs and some smectite-class hydrated IDPs may be comets. On the other hand, parent bodies of most of IDPs and a part of undehydrated micrometeorites are probably asteroids which are different from the meteorite parent bodies.