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Risk assessment and binding mechanisms of potentially toxic metals in sediments from different water levels in a coastal wetland

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Journal of Environmental Sciences 2023年第7期129卷 202-212页

作者： Fusheng Sun Guanghui Yu Xingxing Han Zhilai Chi yunchao lang Congqiang Liu Institute of Surface-Earth System Science School of Earth System ScienceTianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai RimTianjin UniversityTianjin 300072China

The excessive accumulation of potentially toxic metals(Pb and Cd)in coastal wetlands is among the main factors threateningwetland ***,the effects ofwater table depth(WTD)on the risk and binding mechanisms of potentially toxic metals in sediments remain ***,sediments from different WTD obtained from a typical coastal wetland were evaluated using a newly developed strategy based on chemical extraction methods coupled with high-resolution *** findings indicated that the WTD of the coastal wetland fluctuates frequently and the average enrichment factor for Pb was categorized as minor,whereas Cd enrichment was categorized as ***-resolution spectroscopy techniques also demonstrated that organic functional groups and partly inorganic compounds(e.g.,Fe-O/Si-O)played a vital role in the binding of Pb and Cd to surface ***,mineral components rather than organic groups were mainly bound to thesemetals in the bottom ***,our findings provide key insights into the potential health effects and binding characteristics of potentially toxic metals in sediments,as well as their dynamic behavior under varying sediment depths at a microscale.

关键词： Coastal wetlands Wetland sediment Toxic metals Risk assessment Synchrotron radiation Binding mechanisms

Using seismic surveys to investigate sediment distribution and to estimate burial fluxes of OC, N, and P in a canyon reservoir

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Acta Geochimica 2019年第6期38卷 785-795页

作者： Ningxiao Yu Yong Qin Feng Hao yunchao lang Fushun Wang School of Environmental and Chemical Engineering Shanghai UniversityNo.99Shangda RoadBaoshan DistrictShanghai 200444China Institute of Surface-Earth System Science Tianjin University92 Weijin RoadNankai DistrictTianjin 300072China

As a high-precision survey method,seismic surveying has been increasingly applied to inland water research,although its application to artificial reservoirs has remained *** a special artificial water body,reservoirs have important effects on the fluvial transport of material from land to ocean,and inevitably have complex terrain which can complicate and distort the results of seismic ***,there are still some problems need to be resolved in the application of seismic surveys in reservoirs with complex *** this study,the Dongfeng Reservoir located in the upper reaches of the Wujiang River was chosen as an example to test the seismic survey *** testing showed that(1)because of the complex underwater terrain,the signal-to-noise ratio of the echo signal in canyon reservoir is low,making it difficult to determine sediment layers thicknesses in some areas;and(2)due to the large spatial heterogeneity of sediment distribution,insufficient density of cross-sections can lead to inaccurate interpolation *** improve the accuracy of calculations,a mathematical method was ***,the total burial mass of sediment was estimated at 2.85 x 107 tons,and the average burial rates of total organic carbon,total phosphorus,and total nitrogen were estimated at 0.194,0.011,and 0.014 g cm-2 year-1,*** values were close to the results of previous studies and hydrographic station data,indicating that seismic survey can be a reliable and efficient method for the mapping of reservoirs.

关键词： Dongfeng Reservoir Seismic survey Sedimentation Nutrients burial fluxes

Flux of organic carbon burial and carbon emission from a large reservoir: implications for the cleanliness assessment of hydropower

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Science Bulletin 2019年第9期64卷 603-611页

作者： Fushun Wang yunchao lang Cong-Qiang Liu Yong Qin Ningxiao Yu Baoli Wang School of Environmental and Chemical Engineering Shanghai University Institute of Surface-Earth System Sciences Tianjin University

Accurately quantifying the budget of carbon sources and sinks in hydropower reservoirs is important for evaluating the cleanliness of hydroelectricity. However, current research on carbon emissions from reservoirs has rarely taken into account the organic carbon(OC) buried in sediment. Only greenhouse gas emissions from the water-air interface at reservoirs have been examined, which would result in an overestimation of the greenhouse effect of reservoirs. In November 2017, this study investigated the distribution of sediment in the Hongfeng Reservoir(HFR) in southwest China, a typical large hydropower reservoir, by using an underwater seismology monitoring system. We estimated the flux of OC into sediment using the results of a sediment survey and a dataset compiled from references. Our results show that, the HFR retained 200,715 t of OC in the sediment since its impounding after dam construction to the sampling year of 2017, when the average burial flux was 3,521 t-C aà1(106 g C aà1) and the modern burial flux was 5,449 t-C aà1. After excluding the exogenous OC, the modern valid carbon sink of the sediment was 4,632 t per year. Under the current state of the reservoir, taking the modern valid carbon sink value, the carbon emissions from the reservoir's surface, and the discharge water from the dam into consideration, the net carbon sink of the HFR is found to be 1,098.9 t-C aà1. If the hydroelectricity generated by the reservoir is converted to a carbon sink, then the total net carbon sink becomes 12,972.9 t-C aà*** work argues that both reservoir sediment and hydroelectricity are important carbon sinks and both should be included in assessments of the greenhouse effects of reservoirs.

关键词： The Hongfeng Reservoir Sediment Carbon sink Underwater seismology method

Progress in XCAMS at Tianjin University

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Radiation Detection Technology and Methods 2019年第4期3卷 38-45页

作者： Kejun Dong yunchao lang Sheng Xu Institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China

Background A compact ^(14)C AMS system extended for ^(10)Be and ^(26)Al(XCAMS)was installed at Tianjin University in Octo-ber *** an initial testing result,a detection limit of 4.4×10^(−16) for ^(14)C/^(12)C,3.8×10^(−15) for ^(10)Be/^(9)Be and 6.9×10^(−15) for ^(26)Al/^(27)Al was achieved,*** The system was gradually smoothed and optimized based on a series of standard,blank and real samples *** The detection limit was down to 4.0×10^(−16) for ^(14)C/^(12)C,2.2×10^(−15) for ^(10)Be/^(9)Be and 5.6×10^(−15) for ^(26)Al/^(27)Al,*** than one thousand samples of ^(14)C,^(10)Be and ^(26)Al have been successfully measured and *** The cosmogenic multi-nuclide of ^(14)C,^(10)Be and ^(26)Al AMS has been available for studies in archaeology,Earth science and environmental science,and some significant jobs still need to be carried out in the near future.

关键词： XCAMS ^(14)C ^(10)Be ^(26)Al

Chronological Study of Coal-seam Water and its Implication on Gas Production in the South Qinshui Basin

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 207-219页

作者： CHEN Biying FANG Lujia lang yunchao XU Sheng LIU Congqiang ZHANG Luyuan HOU Xiaolin Institute of Surface-Earth System Science School of Earth System ScienceTianjin UniversityTianjin 300072China Institute of Earth Environments Chinese Academy of SciencesXi’an 710061China

The knowledge of the residence time of formation water is fundamental to understanding the subsurface flow and hydrological *** better identify the origin and evolution of coal seam water and its impact on gas storage and production,this study collected coalbed methane co-produced water in the southeast Qinshui Basin and detected chemical and isotopic compositions,especially 36Cl and 129I *** calculated tracer ages of 129I(5.2–50.6 Ma)and 36Cl(0.13–0.76 Ma)are significantly younger than the age of coal-bearing formation(Pennsylvanian-Cisuralian),indicating freshwater recharge after coal *** model that utilises 129I/I and 36Cl/Cl ratios to constrain the timing of recharge and the proportion of recharge water reveals that over 60%of pre-anthropogenic meteoric water entered coal seams since 10 Ma and mixed with residue initial deposition water,corresponding to the basin inversion in *** spatial distribution of major ion concentrations reveals the primary recharge pathway for meteoric water from coal outcrops at the eastern margin to the basin *** study demonstrates the occurrence of higher gas production rates from wells that accept water recharge in recent times and suggests the possible potential of the non-stagnant zones for high gas production.

关键词： CBM co-produced water iodine-129 chlorine-36 water chemistry Qinshui Basin

Sulfate sources constrained by sulfur and oxygen isotopic compositions in the upper reaches of the Xijiang River,China

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Acta Geochimica 2017年第4期36卷 611-618页

作者： Jing Liu Siliang Li Jun Zhong Xuetao Zhu Qingjun Guo yunchao lang Xiaokun Han The State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 55002China University of Chinese Academy of Sciences Beijing 100049China Institute of Surface-Earth System Science TianjinUniversityTianjin 300072China Center for Environmental Remediation Institute ofGeographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

While it is critical to accurately understand the sources and transformation of sulfate based on time-series analysis, there are limited studies on temporal variation of sulfate in rivers and on rock weathering by sulfuric *** conducted a monthly sampling campaign in the Beipan, Nanpan, and Hongshui Rivers over the course of one hydrological year. This study examined seasonal variations in riverine sulfate impacted by the monsoon climate in the upper reaches of the Xijiang River basin. In general, the SO_4^(2-) contents in these rivers dropped from relatively high levels to low values during the high-flow season, in response to increasing discharge. The sulfate was generally enriched in heavy isotopes during the low-flow season compared to the high-flow season. The calculated results indicate that the riverine sulfate was mainly derived from sulfide oxidation, but that evaporite dissolution could be an important source during the low-flow season, based on isotopic evidence. Mine drainage is likely an important source of sulfate to these rivers during the high-flow season due to contributions from fast surface flow, which responds to frequent heavy rain in monsoonal climate regions. Arelatively high proportion of HCO_3^- was found to be derived from rock weathering by sulfuric acid during the high-flow season when compared to that observed during the low-flow season. The results suggest that approximately one quarter of the HCO_3^- in the Hongshui River originated from carbonate weathering by sulfuric acid derived from the oxidation of sulfide. Such information on the specific dual isotopic characteristics of riverine sulfate throughout a hydrological year can provide unique evidence for understanding the temporal variability of sulfate concentrations and weathering processes in rivers.

关键词： Sulfur isotope Oxygen isotope Riverine sulfate Carbonate weathering Xijiang River

The new AMS facility at Tianjin University

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Radiation Detection Technology and Methods 2018年第1期2卷 207-212页

作者： Kejun Dong yunchao lang Nan Hu Jun Zhong Sheng Xu Thilo-Michael Hauser Ross Gan Institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China National Electrostatics Corp. MiddletonWI 53562USA Hakuto Enterprises Ltd Hong Kong 999077China

Introduction Accelerator mass spectrometry(AMS)has been used for the analysis of a lot nuclides in many scientific fields and is one of the most optimal methods to determine very low concentrations of long-lived *** XCAMS system is an extension of the Compact ^(14)C Accelerator Mass Spectrometer for ^(10)Be and ^(26)Al.A description of the first Chinese XCAMS system and initial performance of three nuclides of ^(14)C,^(10)Be,and ^(26)Al,respectively,will be *** procedures Solid sample material(graphite,Al_(2)O_(3),and BeO)is loaded into cathode holders for AMS *** negatively charged ions(C−,Al−,and BeO−)are extracted and accelerated to the terminal,broken-up,and some orbital electrons stripped off to form positively charged atomic ions,and accelerated *** the post-acceleration region,the magnetic and electrostatic devices act on momentum and energy analysis,respectively.A multi-anode detector is used for the identification and detection of relevant isotopes and *** performance The test criteria of three rare isotopes each were set for beam current intensity,measurement precision,and machine *** corresponding material and cathode holder were,respectively,used for ^(14)C,^(10)Be,and ^(26)Al *** batches of real sample have already been analyzed by the new AMS system based on the acceptance test *** addition,several secondary standards were measured to check the stability of the *** The new XCAMS facility has been installed successfully,and the latest performance also showed that the machine is reliable enough,in *** the hardware components and software system were in good condition for accurate and precise data analysis in the near future.

关键词： XCAMS ^(14)C ^(10)Be ^(26)Al

Using the dual isotopes approach to identify the nitrate sources of karst groundwater, Guiyang, Southwest China.

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Chinese Journal Of Geochemistry 2006年第B8期25卷 173-174页

作者： Siliang LI Congqiang LIU yunchao lang The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Using the dual isotopes approach to identify the nitrate sources of karst groundwater, Guiyang, Southwest China.

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Acta Geochimica 2006年第S1期 173-174页

作者： Siliang LI, Congqiang LIU, yunchao lang The State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China