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Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vapor-water exchange among atmosphere, soil and groundwater plays an important role in the surface ecological restoration in the vadose zones of arid and semiarid regions. However, it is limited to in-situ monitoring of water vapor flux, due to the complex and uncertain process. The simulation of water vapor cannot be fully verified by the measurement. It is still lacking in the vapor-water migration at different spatial and temporal scales. This study aims to clarify the spatiotemporal variation and migration of vapor-water exchange in the vadose zone of Mu Us Sandy Land by in-situ vapor-water monitoring, isotope tracer and numerical analysis. The results showed that the δDL and δ18OL of precipitation were enriched in spring and summer, but depleted in autumn and winter, due to the atmospheric water vapor source and local circulation. Soil evaporation was enriched in the oxygen isotope (δ18Oa ) of surface soil vapor-water in summer more than that of soil freezing in winter. Moreover, there was a significant positive correlation (P<0.01) in the δ18O profile of the soil vapor-water and liquid water at different depths. The reason was that the evaporation intensity source and migration mode of soil vapor-water varied greatly in seasons. The δ18O values of vapor water in spring and summer showed an extremely significant linear positive correlation with the liquid water (P<0.01), while there was no significant correlation in winter (P=0.12). Moreover, there was a positive linear relationship between water vapor flux and δ18Oa . Furthermore, the δ18Oawas enriched in the surface layer at the large water vapor flux, including both downward and upward migration. The surfaceδ18Oa was enriched in the period of soil freezing in winter, particularly with the decrease of water vapor density (November-March). But the surface layer δ18Oa increased in summer (May-October) as well with the increase of surface water vapor density. Driven by the gradient of soil temperature in the vadose zone, the replenishment relationship of water vapor throughout the profile varied greatly at different periods. The water vapor of shallow soil was the supply source of deep vapor-water in summer, while the recharge was received from the deep layer in winter. But there were the temperature convergence and divergence zero flux planes in spring and autumn, respectively. The recharge characteristics caused the complicated relationship of vapor recharge in the profile. The soil δ18Oa was controlled by the water vapor migration, atmospheric evaporation and soil freeze-thaw in the vadose zone. In winter, the reduced evaporation and upward transport of water vapor can concurrently cause to enrich the surfaceδ18Oa, thus resulting in a decrease in the correlation between soil water vaporδ18Oa and liquid water δ18OL. While in summer, the dominant effect can be from the diurnal evaporation and condensation cycle of soil water. The findings can provide a scientific basis to clarify the migration of soil water vapor in the water circulation. [ABSTRACT FROM AUTHOR]

Copyright of China Surfactant Detergent & Cosmetics is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Scientiarum Naturalium Universitatis Pekinensis is the property of Editorial Office of Acta Scientiarum Naturalium Universitatis Pekinensis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

"Tobacco-free" or synthetic nicotine products have been favored by the majority of young people, which undoubtedly increase the potential health risks and regulatory challenges. Currently, there are few reliable methods for the determination of authenticity of natural nicotine and synthetic nicotine. The analytical techniques based on mass spectrometry have broad application prospects in component sequence analysis. structure analysis, molecular weight determination and component content determination. The synthesis processes of natural nicotine and synthetic nicotine are different, and their isotopic fractionations are also different. Here, a method of tandem mass spectrometry based on isotope model peak was developed using this feature. The source or naturalness of nicotine is verified by comparing the abundance and area ratio of [M + H]+ and [M+H+1]+ peaks of nicotine, and the abundance ratio of [M+H]+ and [M+H+1]+ peaks as fragments of parent ions. A total of 47 experimental results showed that the m/z 164. 1. 163. 1 peak abundance ratios and the area ratios of natural nicotine and synthetic nicotine in MS spectra were significantly different. In addition, in MS/MS spectra, the abundance ratios of fragment ions of m/z 163. 1. 164. 1 also had significant differences. Among the variables with significant differences. the overall abundance ratio of synthetic nicotine was higher than that of natural nicotine. The evaluation model for the identification of natural nicotine and synthetic nicotine was further constructed by combining chemometric methods. Using OPLS-DA modeling, the discriminant accuracy was 97. 87%. Moreover, rankings of importance of variables differed depending on the model of the evaluation. 164. 1-85. 1/84. 1, 164. 1-85. 1/(84. 1+85. 1), 163. 1-131. 1/131. 1. 163. 1-131. 1/(130.1+131. 1) were the key discriminant variables. This method has the advantages of simple operation, rapid operation and no need for quantitative analysis, which will help to accurately identify, label and supervise tobacco products from different nicotine sources on the market. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND With mining activities taking place on a global scale, the concern for environmental issues within and around mines continues to increase. The advent of multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) has promoted the geochemical study of isotopes and has led to the widespread use of isotope tracing techniques to investigate various issues in the mining environment. OBJECTIVES To systematically summarize the various types of studies currently conducted on the application of isotope tracing technology in mining environments, with the aim of highlighting the importance of the application of isotope tracing technology in complex mining environments and the diversity of scientific problems it can solve. METHODS Data published by scholars at home and abroad by July 2022 has been collected and compiled on testing and analyzing the supply source/connection of mine water body, sulfate/carbonate source and the cause of acid mine wastewater (AMD), migration and transformation of mining elements, different sources and contribution rates of heavy metal pollution with the help of isotope tracer technology. The study area covers more than 40 regions in 20 countries. RESULTS It is found that hydrogen and oxygen isotope tracing techniques in water bodies are effective tools for mine water source analysis, hydraulic linkage studies and AMD source identification. Sulfate sulfur and oxygen isotope tracing techniques provide important support for the study of sulfate sources in mine environments, AMD acidification processes and pollution, bacterial sulfate reduction and elemental migration transformation. Heavy metal isotope (Pb, Cd, Zn, Hg isotopes) tracing technology is an effective way to investigate the sources of metal pollution in mines and nearby environments and the contribution of different sources. CONCLUSIONS Although isotope techniques play an important role in resolving the sources of environmental pollutants in mines and the mechanisms of migration and transformation of characteristic pollutants and revealing the hydrogeochemical processes in mines, most of the current studies are limited to the application of single/few isotopes for short time tracing studies of environmental media in mines. Therefore, further development of multi-isotope tracing technology is needed in the future, as well as long-term and continuous monitoring and investigation of various problems in the mine environment. New and effective methods for pollution prevention and control are also proposed.

Southwest China is the largest concentrated karst landscape distribution area in the world, with dense river networks and abundant hydroelectric resources in the area, which is an important area for the development of hydroelectric power generation in China. To elucidate the impact of karst reservoirs on the carbon cycle of the river system, this work summarizes the research progress of damming in karst watersheds on different forms of carbon transport transformation and the environment in recent years. Through the study of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), particulate inorganic carbon (PIC) and particulate organic carbon (POC) transport and transformation and their control mechanisms in the river-reservoir system in the karst region by spectroscopy, stability and radioisotopes, this work found that the carbon cycle in karst reservoirs exhibits obvious seasonal distribution characteristics, as well as cascade reservoirs, which may further amplify a single reservoir's environmental influence. These results not only contribute to the understanding of the reservoir carbon cycle but also help to explore the "missing" carbon sinks in the river carbon cycle and to more accurately assess the role of karst reservoirs in the global river carbon cycle. In general, karst reservoirs are likely to be more responsive to increased anthropogenic activities than nonkarst reservoirs, which implies that the role of karst reservoirs in the global warming trend needs to be more accurately assessed, and in future research, a systematic characterization of the carbon transport and transformation of different forms from microscopic to macroscopic levels by different analytical tools will more accurately answer this question.

Copyright of Steel Pipe is the property of Steel Pipe Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The coexistence of ammonium, arsenic and dissolved iron in groundwater is a common phenomenon in aquifer systems. They have a strong interaction and affect the nitrogen cycling and the migration and transformation of arsenic in groundwater systems. Based on the systematic survey of international and national literature on the process and influencing factors of groundwater nitrogen cycling, the functional microorganisms and their characteristics related to groundwater nitrogen cycling, and the hydrogeochemical process of arsenic enrichment in groundwater, this paper deciphers effects of nitrogen cycling (including nitrification, denitrification, Feammox, Anammox, and dissimilatory nitrate reduction to ammonium) on the migration and transformation of arsenic in groundwater. We proposed that the dynamic transformation of iron oxides and dissolved Fe (II) in aquifers is an important bridge for nitrogen cycling and the migration and transformation of arsenic in groundwater. The processes of nitrogen cycling in aquifers with different redox environments, the coupling mechanism between nitrogen cycling and arsenic migration and transformation, the interactions among Fe(III) - Fe(II) cycling, nitrogen cycling, and arsenic migration and transformation, nitrogen-iron-arsenic cycling in the surface water-groundwater interaction zone and its response to human activities are important scientific issues and research trend that need to be paid attention to in this field in the future. The solution of these scientific problems is not only conducive to identifying the source, migration and transformation of nitrogen in groundwater, but also beneficial to improving the systematical understanding of enrichment mechanism of groundwater arsenic.

BACKGROUND: With mining activities taking place on a global scale, the concern for environmental issues within and around mines continues to increase. The advent of multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) has promoted the geochemical study of isotopes and has led to the widespread use of isotope tracing techniques to investigate various issues in the mining environment. OBJECTIVES: To systematically summarize the various types of studies currently conducted on the application of isotope tracing technology in mining environments, with the aim of highlighting the importance of the application of isotope tracing technology in complex mining environments and the diversity of scientific problems it can solve. METHODS: Data published by scholars at home and abroad by July 2022 has been collected and compiled on testing and analyzing the supply source/ connection of mine water body, sulfate/ carbonate source and the cause of acid mine wastewater (AMD), migration and transformation of mining elements, different sources and contribution rates of heavy metal pollution with the help of isotope tracer technology. The study area covers more than 40 regions in 20 countries. RESULTS: It is found that hydrogen and oxygen isotope tracing techniques in water bodies are effective tools for mine water source analysis, hydraulic linkage studies and AMD source identification. Sulfate sulfur and oxygen isotope tracing techniques provide important support for the study of sulfate sources in mine environments, AMD acidification processes and pollution, bacterial sulfate reduction and elemental migration transformation. Heavy metal isotope (Pb, Cd, Zn, Hg isotopes) tracing technology is an effective way to investigate the sources of metal pollution in mines and nearby environments and the contribution of different sources. CONCLUSIONS: Although isotope techniques play an important role in resolving the sources of environmental pollutants in mines and the mechanisms of migration and transformation of characteristic pollutants and revealing the hydrogeochemical processes in mines, most of the current studies are limited to the application of single/ few isotopes for short time tracing studies of environmental media in mines. Therefore, further development of multiisotope tracing technology is needed in the future, as well as long-term and continuous monitoring and investigation of various problems in the mine environment. New and effective methods for pollution prevention and control are also proposed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Multi - collector inductively coupled plasma - mass spectrometry ( MC - ICP - MS) has been widely applied to accurate and precise measurements of isotope ratios due to its high sample throughput, strong ionization ability of ICP sources and high mass resolution. For decades, the standard - sample bracketing (SSB) method has been used to correct for instrumental mass bias during the measurement to achieve accurate results. When the content of the target isotope in samples is low, the measurement results are easily influenced by the background signals. “On Peak Zero” correction deducts the background signal from the total signal, which is an effective method to eliminate the background interference and has been widely used, but no research has been conducted to systematically explore the mathematical principles behind this correction. OBJECTIVES: To establish a mathematical model for the “On Peak Zero” correction, and verify its confidence by applying it to isotope measurements of different concentrations of Li, S, Fe, Sr, Nd and Pb standard solutions. METHODS: In this study, a mathematical model of the influence by the background signal on isotopic composition was established by mathematical reasoning and approximate substitution. Standard solutions of different concentrations of Li, S, Fe, Sr, Nd and Pb were prepared for the application of the “On Peak Zero” method through experimental analysis. Two types of blank signals were subtracted separately from the aggregate signals to simulate isotope measurements without and with “On Peak Zero” correction. RESULTS: The results indicate that the lower the concentration of the target element, the greater is the blank solution signal influence on the accuracy of the sample to be tested, and the “On Peak Zero” method can better eliminate the influence of the blank solution on the sample measurements. The simulation results based on this model were consistent with the real experimental results in this study. CONCLUSIONS: The mathematical model and the data explain well the effect of background concentration on the experimental isotope values, and are useful for understanding the application of the “On Peak Zero” method in MC-ICP-MS isotope analysis. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Resources is the property of Geology & Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Study on water vapor transport is beneficial for better understanding the process of extreme precipitation. However, the precipitation system is complex and precipitation isotopes exhibit randomness, which makes it large uncertainty to use precipitation isotopes to trace water vapor transport. Information entropy has been employed to study the probability distribution characteristics of precipitation isotopic compositions in China, and it shows a strong linear relationship between hydrogen and oxygen precipitation isotopic information entropies, with a slope that is close to one. The spatial and temporal distributions of precipitation isotope information entropy were compared with the mean value of precipitation isotopes. Results showed that the spatial distribution of precipitation isotopic information entropy can suitably reveal the movement of water vapor from the ocean to continents, but this feature is not reflected by the spatial distribution of the mean value of precipitation isotopes. Precipitation isotope information entropy was applied to trace the three moisture corridors driven by monsoon system in China. Results showed that the spatial distribution of precipitation isotope information entropy can accurately reflect the vapor source and movement of the three moisture corridors and their seasonal changes. [ABSTRACT FROM AUTHOR]

Ecological restoration has been one of the most important strategies for the ever-increasing ecosystem degradation and environmental pollution in the world. A great challenge can be also posed on the Baiyangdian Lake, the largest fresh water lake in the North China Plain, particularly for the water deterioration, biodiversity decline, and ecological function disorder. In this study, a comprehensive restoration project was implemented to restore the fishery resources in the ecosystem of Baiyangdian Lake. Some ecological restoration techniques were utilized to create habitats for the aquatic animals, aquatic plant diversity, and stock benthic organisms during the change of the bottom. A systematic evaluation was conducted to determine the regulation effect of the project on the community structure of fishery resources and the nutritional relationship between species. An investigation was also performed on the fishery resources, food web structure, and nutritional level, where the Shihoudian Lake (restoration area) was selected as the research object, and Dabaiyangdian Lake as the control. Six sampling points were set in the two areas at the same time. The results showed that the ecological restoration project increased the catch species, abundance and biomass by 35.29%, 58.60%, and 200.00%, respectively, in the restoration area, compared with the control. The fish’s physical signs in the restoration area (the total length of (125.04±54.97) mm, the body length (100.22±44.44) mm, and body weight (44.02±331.45) g on average) were much higher than those in the control area (the total length 106.94±35.47mm, the body length (85.79±29.66) mm, and the body weight (19.77±82.30) g on the average). The average physical characteristics for the six types of fish (Carassius auratus, Pseudobagrus fulvidraco, Cultrichthys erythropterus, Toxabramis swinhonis, Protosalanxh yalocranius, and Rhinogobius giurinus) in the restoration area were significantly higher than those in the control area (P<0.05).The C/N stable isotope analysis showed that the mean value of δ13C and δ15N in the restoration area was higher than that of the control area, regardless of the whole catch, fish population, or invertebrate population. The one-way analysis of variance (ANOVA) of δ13C and δ15N between the two areas showed that there were significant differences (P<0.05) among the whole catch, while the fish population only had significant differences in δ15N (P<0.05) and invertebrate population only had significant differences (P<0.05) in δ13C. In addition, the δ13C span of the restoration area (6.30‰) was significantly higher than that of the control area (4.47 ‰), indicating the more abundant food organisms and the more complex food web structure in the restoration area. The trophic level analysis demonstrated that the trophic level range, the total span, and average (1.93-3.96, 2.03, and 2.99±0.66) of the main fishery organisms in the restoration area were higher than those in the control area (1.94-3.89, 1.95, and 2.76±0.70). The species with the highest trophic level in the restoration and control area were Cultrichthys erythropterus (3.96), and Silurus asotus (3.89), respectively. Meanwhile, the species number with a trophic level between 3-3.5 in the restoration area was the highest (30.43%), while the species number with a trophic level between 2.5-3 in the control area was the highest (41.18 %). Therefore, the ecological restoration project can be expected to effectively improve the biodiversity, the stable ecosystem structure, and the rapid restoration of ecological functions and fishery resources in the Baiyangdian Lake. [ABSTRACT FROM AUTHOR]

Carbonate rocks, as one of the magmatic rocks with little but significant geological significance in nature, are generally considered to be mantle-derived causes, and shell-derived causes are rarely reported. The exposed dioprosene carbonate in the Annamba area of the southeast edge of the Tarim Basin is irregular and vein-like intrusive into the surrounding rock, and the surrounding rock trapper body can be seen inside the rock, and has a dense block structure and fine grain structure, indicating that it is an igneous carbonate rather than a sedimentary carbonate rock. The geochemical characteristics of rocks show that the carbonate-rich CaO (content (mass fraction, the same below) is 24.63%-33.20%), SiO (33.11%-40.07%), poor MgO (2.25%-3.21%), FeO (1.38%-2.03%), the total rare earth element content ((45.44-91.47) ×10) and the total light rare earth element content ((42.83-86.06)×10) are significantly lower, and the relative enrichment Rb is significantly lower Large ionic lithophilic elements such as Ba, Th, Sr, etc., with losses of Nb, Ta, Zr, Hf and other high field strength elements, are obviously different from mantle-derived carbonate rocks, and similar to shell-derived carbonate rocks. Zircon in the dioprose carbonate develops oscillating ring band structure, with obvious Ce positive anomaly, weak Eu negative anomaly and low Th/U value (average value 0.24), indicating that it is metamorphic deep molten zircon. The study of the U-Pb-Lu-Hf isotope of zircon zircon showed that the age of the zircon Hf isotope pattern had an age peak of about 2.59 Ga, and the age of lithogenesis was (1 910±13) Ma, which was consistent with the formation era of the Milan rock group and the era of hemp grain phase metamorphism, respectively. Combined with the comprehensive analysis of the previous research results, it is believed that the dipyrene carbonate in the Annamba area may be the product of the deep melting action of the Diopline Dali rock of the Milan rock group under the condition of hemp granular phase metamorphism, which is the response of the Columbia supercontinent aggregation event in the southeast edge of the Tarim Basin [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Spatiotemporal variation of nitrate (NO3 ¯ ) and isotope components were investigated in the karst and non-karst sub-basins, to clarify the influence of hydrogeological conditions and underlying surface properties on the source and migration of nitrate in water. The research areas were selected as the Mudong and the Jingui sub-basin in the Qingshitan Reservoir Irrigation District of Lijiang River Basin in southwest China. Both small karst watersheds were also dominated by agricultural activity. Multiple isotopes (δD-H2O, δ18O-H2O, δ15N-NO3 ¯, and δ18O-NO3 ¯ ) and the Bayesian Model Stable Isotope Analysis in the R (SIAR) model were applied to compare the multiple potential nitrate sources in the water. The results indicated that the spatial and temporal variation of nitrate in water depended on the hydrogeological conditions and the associated topography, soil characteristics, and land use types of the sub-basin. Total nitrogen (TN) was mainly formed by NO3 ¯ and NH4 + in the river, where the proportion of NO3‾ was slightly higher while decreasing along the river. TN was overwhelmingly dominated by NO3‾ in the shallow groundwater. Nitrification was the dominant process of NO3 ¯ formation and transformation. The Jingui sub-basin included the woodland with a thicker soil layer, while the Mudong sub-basin was mainly agricultural land with the karst development and the discontinuous thin soil layer. The ranges of mean NO3 ¯ concentration (0.19-15.84 mg/L), and the isotope values of δD-H2O (from -44.08‰ to -19.63‰), δ18O-H3O (from -7.24‰ to -1.55‰), δ15N-NO3 ¯ (from -1.65‰ to 53.98‰), and δ18O-NO3 ¯ (from 0.04‰ to 13.74‰) in the Mudong sub-basin, were all greater than those in the Jingui sub-basin. In terms of spatial distribution, the mixing of nitrogen fertilizer infiltration from the orchard of exposed karst stone mountain in the north recharge area and manure & septic waste infiltration from the village groups were not smoothly dispersed and discharged in the central tectonic basin region, resulting in the high concentration of NO3 ¯ (the mean concentration range from 11.96 to 15.84 mg/L) and the high isotope value of δ15N-NO3 ¯ (from 0.65‰ to 28.23‰) and δ18O-NO3 ¯ (from 2.46‰ to 14.43‰) in the water of G4-G7 wells. The contributions of NO3 ¯ sourced from the soil nitrogen in the dry season, as well as the manure and septic waste in the wet season in the Mudong sub-basin, were less than those in the Jingui sub-basin. The reason was the low capacity of water storage in the thin soil layer that was formed by the weathering of carbonate rocks, together with the strong permeability of the shallow soil layer in the Mudong sub-basin. Consequently, spatial and temporal variations of nitrate pollution and migration in water were achieved under karst hydrogeological conditions and underlying surface properties. The finding can provide decision support for the control of agricultural non-point source pollution and the improvement of the water environment in karst and non-karst areas. [ABSTRACT FROM AUTHOR]

Nowadays, more than 160 granitic plutons have been confirmed to form in Caledonian ( including Ordovician, Silurian, and Devonian), since Longhui and Shangyou plutons in Jiangxi were firstly found in the 1950s. Among them, only 14 plutons are genetically related to the polymetallic mineralizations (major W with minor Mo, Cu, Sn, and Au), and 11 plutons are related to the REE mineralizations. Previous studies on Caledonian granites were mainly concentrated on the characteristics of petrology, geochemistry, and tectonic dynamics, but hardly on the mineralization. Based on 800 mineralization and crystallization ages, the data of wholerock elements of 1 248 samples, the whole-rock Sr-Nd isotopes of 428 samples, and the zircon Lu-Hf isotopes of 2 352 analytical spots, which were collected from 280 papers and theses, four main conclusions about metallogenic characteristics of Caledonian granites were summarized as follows: CD 440- 420 Ma is the peak of magmatic activity and metal mineralization; @ Metallogenic granites are mainly focused in Dayaoshan and north-northeast areas of Guangxi, and their source materials and differentiation degrees are all different with each other; @ REE forming granites are primarily concentrated in Wuyi and Nanling areas, and most of the former experienced the metamorphism, but the latter did not; © Compared with Ordovician and Devonian granites, Silurian granites have the largest distribution area, the broadest lithologies, and the complicated source materials. [ABSTRACT FROM AUTHOR]

Stable isotope ratios of carbon, nitrogen, hydrogen and oxygen act as "nature's recorder". A s a carrier for individual human information, human hair can be measured by isotope ratio mass spectrometry ORMS) to translate into information about people's dietary habits, health condition and life track. The basic principle behind establishing dietary lifestyle using isotopic profiles of human hair is the fact that the body's only source of C, N is a person's staple diet. It may have significant differences in carbon, nitrogen isotopic compositions of human hair that are living at different regions. The aim of the study was to analyze the discrepancy of 15N and 13C stable isotope ratios in human hair collected from different cities, and explore the relationship between carbon and nitrogen isotope ratios and human groups, such as gender and age. The carbon and nitrogen isotope ratios in the human hair of 247 local residents from 8 different cities were investigated by IRMS. The results showed that there were significant difference in carbon and nitrogen stable isotope ratios of human hair from different cities. The value of δ13 C was negatively correlated with vegetable consumption per capita. The value of δ15N was positively correlated with meat consumption per capita, and might be increased by high intake of fish. The relationship between δ13C, δ15N and the factors of gender and age demonstrated that there were no significant difference between males and females, but the age of females showed a weakly negative correlation with δ13 C. By comparing the data of this paper and other literatures, the carbon and nitrogen stable isotopes in the hair of residents in China were different from other countries, which implied that there were various dietary habits in different countries. [ABSTRACT FROM AUTHOR]

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Inductively coupled plasma sector field mass spectrometers(ICP-SFMS) mainly include high-resolution ICP-MS (HR-ICP-MS), multi collector ICP-MS (MC-ICP-MS) and full spectrum ICP-MS. The HR-ICP-MS generally adopts the revise Nier-Johnson magnetic-electrostatic sectors double focusing geometry, the MC-ICP-MS generally adopts the forward Nier Johnson electrostatic-magnetic sectors double focusing geometry, and the full spectrum ICP-MS with detector array adopts the Mattauch-Herzog geometry. The performance improvement of ICP-SFMS is mainly reflected in the frequency turning ICP design, which improves the tolerance and reliability to the matrix, the J-type sampler cone and X-type skimmer cone are used to improve the sensitivity, the large pumping speed interface pump can reduce the vacuum in the interface area and improve the sensitivity of the instrument, and the improved ion transfer lens system can improve the abundance sensitivity of actinide isotopes. High resolution isotope ratio can be obtained by changing the slit width in front of the detectors. The use of multiple Daly detectors can improve the detection ability of low abundance isotopes. The signal output of low abundance isotope measurement can be improved by automatically switching the high resistance of Faraday cup amplifier through software. The improvement of the performance of ICP-SFMS makes it more widely used in nuclear geological analysis. In situ U-Pb dating of pitchblende micro area can be carried out by LA-HR-ICP-MS, uranium isotope fractionation can be determined with high precision by MC-ICP-MS, and refractory elements such as U, Th, Nb, Ta, Zr and Hf can be determined by LA-HR-ICP-MS. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) is an important greenhouse gas. High input of water and fertilizer in vegetable production results in large N2O emission. Though drip irrigation is the most commonly used irrigation method in vegetable production, it is still unclear how water and fertilizer interaction under drip irrigation affects N2O emission. Therefore, the objective of this study was to analyze the effects of different fertilizer treatments under drip irrigation on N2O emission and isotopic signatures, and thus provide a theoretical support for reducing N2O emission in vegetable production mainly driven by microbial activity that included Bacterial Nitrification (BN), Bacterial Denitrification (BD), Nitrifier Denitrification (ND), Fungal Denitrification (FD) and N2O reduction to N2. The study was conducted in at the environmental research station of the Chinese Academy of Agricultural Sciences, situated in the Shunyi District, Beijing, China (40°15′N, 116°55′E). The soil of the experiment field was classified as calcareous fluvo–aquic. The Chinese cabbage was sown on 7 August 2015. Under drip irrigation, four fertilizer treatments were evaluated, including inorganic NPK compound fertilizer (NPK), organic fertilizer of sheep manure (M), water-soluble fertilizer of amino acid (WS), and no-fertilizer (NF). Gas and soil samples were collected throughout the study phase. The concentration and isotopic signature values (δ15NbulkN2O and δ18ON2O of N2O), ammonium (NH4+) and nitrate (NO3-) content of soil, soil C/N, and yield of Chinese cabbage were analyzed. Net isotope effect between N2O and H2O and 15N site preference in N2O molecule (SP) were also analyzed and used to distinguish BN/FD and BD/ND and to calculate the extent of N2O reduction to N2. The results showed that the SP had significant positive correlation with both δ15NbulkN2O and δ18ON2O (P<0.01), and significant negative correlation with N2O emission fluxes (P<0.01) and Water Filled Pore Space (WFPS, P <0.05). It indicated that using SP vs. δ18ON2O to quantitatively analyze production and consumption pathways of N2O was feasible and water content significantly affected the activity of soil microorganisms. Under approximately 60% WFPS condition, for the NPK, M, WS and NF treatments, the N2O emission were 1 074, 146.5, 116.2 and 112.9 μg/(m²·h), respectively. The Nitrogen Use Efficiency (NUE) of the NPK, M and WS were 45.1%, 22% and 45.2%, respectively. The yield of Chinese cabbage of the NPK, M, WS and NF were 147.9, 116.5, 127.5 and 86.4 t/hm², respectively, and the contribution of nitrification were 38%, 46%, 54% and 49%, respectively, and the extent of N2O reduction were 14%, 71% 46%, and 70%, respectively. The water-soluble fertilizer treatment showed the highest NUE and relatively low N2O emission, and both inorganic fertilizer treatments showed the low extent of N2O reduction, which was unfavorable for reducing N2O emission during denitrification. In contrast, organic fertilizer treatment had the highest the extent of N2O reduction, which was the main pathway to reduce N2O emission during denitrification. Therefore, this study suggests that organic fertilizer may be used as the base fertilizer with water and fertilizer integration technology as a management practice during the growing season for reducing N2O emission and enhancing NUE. [ABSTRACT FROM AUTHOR]

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In order to understand the change of sea level and sedimentary evolution characteristics of Permian carbonate rocks in Zhenba area of the northeastern Sichuan Basin, the Yangjiawan section in Zhenba county of Shaanxi province was selected. Based on the field characteristics of rock formations and indoor petrology characteristics, and combined with the changes of paleosea level, paleosalinity and paleotemperature reflected by C-0-Sr isotopic composition, the sedimentary evolution characteristics of Permian in Zhenba area of the northeastern Sichuan Basin were comprehensively analyzed. The analysis results of C-0-Sr isotopes show that δ13 C is -1. 67‰-5. 85‰ with an average of 2. 76‰; δ18 0 is - 7. 26‰-- 3. 44‰ with an average of -6. 24‰; the ratio of 87Sr/86 Sr is 0. 707 147-0. 708 133. The changes of paleosea level, paleotemperature (12. 0 oC-25. 2 oC with an average of about 21. 0 oC ), and paleosalinity (salinity indicator is 120. 88-135. 90 with an average of 129. 84) reflected by C-0-Sr isotope compostions, indicate that Zhenba area is warm-hot high-salinity with good water circulation, and the global sea level eustatic events have a good control on the composition of carbonate isotopes; the sea level changes in Zhenba area are basically consistent with global sea level changes, that is, entering a relatively stable and slow decline stage after rapid transgression in early Qixia period, experiencing large-scale transgression in the early Maokou period and sea level decline significantly in the late Maokou period, experiencing large-scale transgression in the early Wujiaping period and regression in the middle Wujiaping period, and experiencing sea level rise in early Changxing period. Based on the comprehensive analysis of sedimentary characteristics, the sedimentary evolution process is open platform→platform edge→shelf→gentle slope in Zhenba area of the northeastern Sichuan Basin. [ABSTRACT FROM AUTHOR]

As one of the rivers with the highest elevation in the world, the Yarlung Zangbo River concentrates more than half of the water resources in Tibet. With the development of cascade hydropower stations in the Yarlung Zangbo River, human activities have changed the ecological environment and affected the nitrogen cycle in the river. In order to clarify the distribution characteristics of nitrogenous compounds and quantitatively analyze their sources, eleven sampling points were set up in the middle and lower reaches of the Yarlung Zangbo River and its main tributaries (Nianchu River, Lhasa River and Niyang River), and water samples were collected in March (the dry season) and August (the wet season) of 2018. The concentrations of dissolved oxygen (DO), total dissolved nitrogen (TDN), NO3 - , NO2 - and NH4 + were measured. Dissolved organic nitrogen (DON) was calculated as the difference between TDN and inorganic N. The occurrences and spatial-temporal distribution of nitrogenous compounds in the water samples of the rivers were analyzed, and the main sources of NO3 - in the wet season were determined by the dual isotope analyses. The results showed that the DON was the main form of TDN. The concentrations of TDN ranged from 1.3 to 2.5 mg/L in the dry season and from 1.1 to 2.0 mg/L in the wet season, and showed a downward trend along the river. The NO3 - -N was the main form of inorganic nitrogen in the water, with an average proportion of 25.6% in TDN, and NH4 + -N accounted for 17.5% in TDN, while NO2 - -N was not detected at the most sampling sites. The results of nitrogen and oxygen isotope analyses showed that the values of δ15N-NO3 - ranged from -9.17‰ to 22.68‰, and δ18O-NO3 - from -13.25‰ to 8.24‰ in the wet season. The NO3 - mainly came from rainfall and fertilizer, organic nitrogen in soil, and sewage and feces. Based on the Stable Isotope Analysis in R (SIAR) model, the contribution rates of nitrate from different sources were quantitatively calculated. In the Shigatse and Lhasa sections, NO3 - in the water body mainly came from the organic nitrogen in soil and the NH4 + in rainfall and fertilizer, with more than 70% of contribution rate. The main sources of NO3 - in the water in the upstream and downstream of the cascade power stations were NH4 + in rainfall and fertilizer, as well as sewage and feces, which accounted for a similar proportion, totally contributing more than 80% of the sources of NO3 - . In the Nyingchi section, the NH4 + in rainfall and fertilizer contributed the most to NO3 -, accounting for 60%-70%, followed by the organic nitrogen in soil with 22%-28% of contribution rate. A large amount of farmland was distributed along the Yarlung Zangbo River and its tributaries. The nitrogen fertilizer applied in the farmland flowed into the river along with the surface runoff through rainfall, which was an important source of nitrogen in the water body of the Yarlung Zangbo River. Due to the reclamation of gentle slopes along the river and the erosion of cultivated soil, the organic nitrogen in soil was another important source of NO3 - in the water of the Yarlung Zangbo River, especially in the wide valley section. Higher contribution rate of sewage and feces to NO3 - in the canyon reach may be related to the development and construction of the cascade hydropower stations in the region. According to the change of DO contents and theoretical and measured values of δ18O-NO3 -, nitrification and denitrification in the Yarlung Zangbo River are the main factors affecting the forms of nitrogen and the composition of nitrogen and oxygen isotopes. The results in the present study can provide data for the pollution control of nitrogenous compounds in the rivers in plateaus and drinking water security in Tibet. [ABSTRACT FROM AUTHOR]

Stable isotope technique is important for understanding the structure and function of soil food web, which is considered as a belowground black box. We reviewed typical application cases of stable isotope techniques in the research of soil food webs, including to determine food sources and feeding preferences of soil fauna by using isotopes, and to analyze the trophic structure of soil food webs through isotope fractionation effects during the process of feeding and nutrient sequestration by soil fauna. Additionally, stable isotope techniques could reveal the role of soil biota at different trophic levels within soil food web in ecosystem matter and energy flow, which favored to carry out accurate and efficient research on the contribution of soil food webs to soil carbon and nitrogen cycling process and the corresponding influence mechanism. We further put forward the limitations of current stable isotope techniques and the future development directions.

别也萨麻斯矿床是目前新发现的分布在新疆北阿尔泰以Li矿化为主的花岗伟晶岩型稀有金属矿床,具有独特性和代表性。矿区发育Li-Nb-Ta矿化和Nb-Ta矿化两类伟晶岩,二云母二长花岗岩是含矿伟晶岩脉群的直接围岩。在系统的野外地质特征调查(包括野外露头和钻孔岩芯赋矿岩系、矿化特征、蚀变类型等的详细观察)基础上,对含矿伟晶岩和二云母二长花岗岩开展了LA-ICP-MS锆石U-Pb定年和原位Hf同位素研究。获得锆石206Pb/238U加权平均年龄分别为(151.0±1.8)Ma和(449.0±4.2)Ma,含矿伟晶岩形成于晚侏罗世,二云母二长花岗岩则形成于晚奥陶世。含矿伟晶岩和二云母二长花岗岩的εHf(t)值分别为0.62～1.30和1.35～6.07,二阶段Hf模式年龄为1 161～1 118 Ma和1 345～1 037 Ma。含矿伟晶岩的εHf(t)值较花岗岩小得多,二阶段Hf模式年龄与形成年龄的差值较花岗岩大得多,表明两者是阿尔泰造山带在不同演化阶段下的产物。悬殊的年龄差、不同的大地构造背景与不同的形成物源表明别也萨麻斯稀有金属矿床含矿伟晶岩与二云母二长花岗岩在成因上并无联系,近矿花岗岩围岩并非含矿伟晶岩脉的真正母体。 [ABSTRACT FROM AUTHOR]

Soil water deficit is the main obstacle factor of plant reconstruction in rocky desertification area of Southwest China. Mycorrhizal mulberry (Morus alba L.) can cope with the main ecological barriers during the seasonal drought in the rocky desertification area. However, it is unclear the water resource of mulberry. In this study, we studied the water use strategy of mulberry root in different seasons by hydrogen and oxygen stable isotope technique. The mulberry was grown in typical rocky desertification area in Qingshuipu town, Qixingguan district, Bijie city (105°35′02′′E, 27°41′19′′N) in Guizhou Province. The precipitation was mainly concentrated in June-September. The mulberry was not irrigated. The annual growth of mulberry was in 2 seasons: from April to June and from September to November. The samples of rainfall water, soil and plant branch were collected from April to November of 2014. Soil was sampled at 0-60 cm depth with 10 cm as a sampling layer. The abundance of deuterium and oxygen stable isotope were measured. The correction analysis method was used to preliminarily evaluate water sources of mulberry. The contribution rate of water at each soil layer was also calculated. The results showed that in rainfall water, the abundance of deuterium from April to November averaged -25.9‰ and the oxygen stable isotope abundance averaged -4.82‰. In spring from April to June, the abundance of deuterium and oxygen stable isotope in rainfall water averaged -0.24‰ and -1.68‰, respectively. In autumn from September to November, the abundance of deuterium and oxygen stable isotope in rainfall water averaged -60.0‰ and -8.17‰, respectively. In spring, the abundance of deuterium and oxygen stable isotope in soil water averaged -29.4‰ and -4.77‰, respectively while the abundance of deuterium and oxygen stable isotope in xylem water averaged -33.2‰ and -5.39‰, respectively. In autumn, the abundance of deuterium and oxygen stable isotope in soil water averaged -70.1‰ and -9.27‰, respectively while the abundance of deuterium and oxygen stable isotope in xylem water averaged -55.7‰ and -7.92‰, respectively. The abundance of both stable isotopes in soil water and xylem water were below that in the rainfall water and that of xylem water were between soil water and rainfall water. It indicated that the mulberry mainly used soil water. Both isotopes in rainwater were more enriched in the early stage of mulberry growth (spring, from April to June) than in the late growth stages (autumn, from September to November). With the seasonal variation of rainfall, the both isotopes of soil water showed a downward trend. According to rainfall water equations, the mulberry absorbed mainly soil water. Both isotopes had clear seasonal trend. In spring, the isotopes in soil water decreased with the increase of soil depth. In autumn, isotopes in soil water decreased then increased with soil depth. Based on the correlation method, the mulberry absorbed water from different soil depth. In spring, it absorbed water from soil below 20 cm while it absorbed water from soil 0-20 cm. In September, it also absorbed water from 50-60 cm soil layer. Based on results from the IsoSource software, in spring, mulberry mainly used soil water from soil layers of 10-30 to 50-60 cm. In autumn, it mainly used soil water from soil layers of 50-60 to 0-10 cm. In spring, the contribution rate was 69.1% by 10-30 cm in soil, 31.8% and 66% by 50-60 cm layer in May and June, 70.2% by 50-60 cm in September and 94.3% and 71.9% by 0-10 cm in October and November, respectively. The study will be helpful to mulberry manage and application in rocky desertification area. [ABSTRACT FROM AUTHOR]

The stable isotope ratio in human hair can be used to trace back the spatial and temporal information of human life. The construction of a comparable database of stable isotope ratio in Chinese human hair has a great significance for forensic science research and public security investigation. However, the interference of sample pretreatment and the difference of normalization methods affected the accuracy and reproducibility of hydrogen isotope ratio measurement and made it difficult to make comparison between laboratories. This research were based on the elemental analysis-isotope ratio mass spectrometer technic (EA-IRMS), and it systematically demonstrate the selection of hydrogen isotopic reference materials and the normalization method of hydrogen isotopic compositions to isotope reference scales. Firstly, six international reference materials (USGS42, USGS43, CBS, KHS, EMAP1 and EMAP2) were selected to evaluate their suitability. Then, according to the range of δ2H values (-55‰～-80‰) of Chinese human hair measured and reported in the literatures, three of them were selected, including the minimum, maximum and middle values of the samples. Finally, by comparing the six reference materials combinations (CBS/USGS42/USGS43, CBS/USGS42/EMA-P1, CBS/USGS42/KHS, EMA-P2/USGS42/USGS43, EMA-P2/USGS42/EMA-P1 and EMA-P2/USGS42/KHS), it is proved that the standard calibration curves fitting R2 (1.000 0±0.000 0, n=4) of USGS42, USGS43 and CBS combinations are the highest, and the coefficients (1.061 8±0.006 6, n=4) of them are the most stability than other combinations by utilizing linear regression of multiple-point normalization method. At the same time, two laboratories in Beijing and Shanghai were selected to carry out 35 repeated validations. The results show that the multiple-point normalization method of the standard combination has the highest fitting degree and good stability (R2≥0.999 7, n=35). It is suitable for the normalization method of hair δ2H and can be used as a recommended method for the construction of Chinese human hair δ2H database. The idea of selecting isotopic reference materials and the normalization method of hydrogen isotopic compositions to isotope reference scales can also provide reference for the establishment of other stable isotope ratio database. [ABSTRACT FROM AUTHOR]

In order to establish more accurately and rapid pretreatment method for the nitrogen stable isotope analysis of soil ammonium nitrogen, diffusion and N2O produced method were compared, and combined with two commercially available equipment’s, i.e., elemental analyzer-isotope ratio mass spectrometer（Flash HT-IRMS） and trace gas preconcentration-stable isotope mass spectrometry（PreCon-IRMS）, respectively, for the analysis of the nitrogen stable isotope abundance inammonium sulfate reference solutions and soil ammonium nitrogen extracted from different paddy soil samples. The stable isotope measurement results showed that both the diffusion and N2O produced method coupled IRMS analytical systems were able to provide good analytical data for ammonium sulfate reference solutions in accuracy with precision of superior to 0.5% and 0.2%, respectively. However, there was a nitrogen isotope fractionation accrued in the diffusion-treated process, and the test results needed to be corrected by a standard curve. At the same time, the 15N-stable isotope abundance in ammonium nitrogen extracted from different paddy soils were determined by diffusion and N2O produced method. The comparison of the analytical data from the two analytical methods indicated that N2O produced method coupled with PreCon-IRMS provided better nitrogen stable isotope data in reproducibility and accuracy than the data obtained by the other method. In addition, through the auxiliary automatic trace nitrogen conversion-N2O generated device, nitrogen stable isotope abundance of soil ammonium nitrogen could be simultaneously analysis online in batch process, and the pretreatment analysis time was short, the sample consumption was small, only need 10 μg N for one sample（<5 mL soil extract solution）. Therefore, for the analysis of nitrogen isotopes in micro-amounts of soil ammonium, the N2O produced method coupled with PreCon-IRMS analysis method has more advantages than the diffusion method coupled Flash HT-IRMS analysis method. [ABSTRACT FROM AUTHOR]

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Halogenated polycyclic aromatic hydrocarbons (H-PAHs), including chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) and brominated polycyclic aromatic hydrocarbons (Br-PAHs), are compounds in which one or more hydrogen atoms replaced by chlorine or bromine atoms. These compounds are not only difficult to degrade but also highly fat soluble and toxic. They are a new type of high-risk organic pollutants with structures similar to those of dioxins, and their toxicity is even higher than that of the parent polycyclic aromatic hydrocarbons (PAHs). The bioaccumulation of H-PAHs can be predicted by their octanol-water partition coefficient ( K ow ); in general, higher bioaccumulation capacity and K ow values indicate greater fat solubility. Therefore, animal-derived foods with higher fat contents, such as animal meat, milk, aquatic products, and their processed forms, are more likely to be contaminated with higher contents of H-PAHs than those with lower fat contents. In this work, a gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) method coupled with stable isotope dilution was established to determine 15 H-PAHs in aquatic products. The instrument and pretreatment methods were systematically optimized. The GC-MS/MS used in this method can effectively eliminate matrix interferences and features high sensitivity and low analytical cost; thus, it has good application prospects. The samples were added with an isotope internal standard before extraction to calibrate the loss of the tested substance during the pretreatment process, extracted by accelerated solvent extraction, purified using gel permeation chromatography and PRiME HLB columns, and then analyzed by GC-MS/MS. The use of two DB-5MS chromatographic columns (30 m×0.25 mm×0.25 μm) and microplate fluidics technology to connect chromatographic columns 1 and 2 in series led to better separation effects, good peak shapes, and high target compound responses. The 15 H-PAHs demonstrated good linearities in the range of 1-50 μg/L, with correlation coefficients ( r ) greater than or equal to 0.993. The relative standard deviation (RSD) values of the relative response factor (RRF) of the H-PAHs were less than 9%, the method detection limit (MDL) was 0.009-0.072 μg/kg, and the method quantification limit (MQL) was 0.031-0.240 μg/kg. Three spiked levels of 0.25, 1.0, 2.5 μg/kg were added to the blank samples to determine the recovery and precision. The recoveries for these spiked levels were 74.6%-116.8%, 77.8%-123.2%, and 71.9%-124.8%, respectively, and the corresponding RSDs were 0.6%-8.2%, 0.6%-9.0%, and 0.4%-10.6%, respectively. The total actual content of H-PAHs in aquatic product samples was 0.60-3.54 μg/kg. Among the H-PAHs investigated, 9-chlorophenanthrene (9-ClPhe) showed the greatest detection rate (100%) and highest content (1.15 μg/kg), indicating that H-PAHs widely exist in aquatic products. Thus, further assessment of the dietary exposure risk of these compounds is necessary. The developed method simplifies the pretreatment step, and has the advantages of simplicity, rapid analysis, high recoveries, and good stability. It is suitable for the qualitative and quantitative analysis of H-PAHs in actual aquatic product samples and provides reliable technical support for the residue status and risk assessment of H-PAHs in aquatic products.

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Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To establish a method for the determination of three furfural compounds in coffee and its products by gas chromatography-tandem mass spectrometry., Methods: The samples were extracted with ethanol water(1∶2, V∶V) solution, ultrasonic with 10% Na&#95;2CO&#95;3 solution for 5 min, purified with 100 mg C&#95;(18), 50 mg Srong Cation exchang(SCX), 150 mg anhydrous MgSO&#95;4, separated by HP-INNOWAX capillary column(30 m×0.25 mm, 0.25 μm), detected by gas chromatography-tandem mass spectrometry, and quantified by isotope internal standard method., Results: The correlation coefficients(r) of the three furfural compounds were all greater than 0.999, the limits of detection were 0.004-0.011 mg/kg, and the limits of quantitation were 0.013-0.031 mg/kg. The average recoveries were 86.0%-112% and the relative standard deviations were 4.1%-10.6%(n=6), at 3 supplemental levels in 3 different coffee substrates. Nine samples of coffee beans, instant coffee and coffee drinks were tested, and all three components to be tested were detected., Conclusion: The method is simple, rapid, sensitive, with good accuracy and precision. It is suitable for the determination of three furfural compounds in coffee and its products.