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Assessment on contaminations in sediments of an intake and the inflow canals in Taihu Lake, China

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Frontiers of Environmental Science & Engineering 2015年第4期9卷 665-674页

作者： Xiaolong WANG shiming ding Qi ZHANG Weiping HU State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Linmology Chinese Academy of Sciences Nanjing 210008 China

As the second largest freshwater lake in China, Taihu Lake provides water supply to approximately 32 million inhabitants around the lake. However, dramatically increased pollution has threatened the safety of drinking water supply in recent years. In the present study, we investigated the contaminations of nutrients and heavy metals in the sediments of an intake and inflow canals in Gonghu Bay, Taihu Lake. Moreover, we also examined the impact of human activities on spatial distribution char- acteristics of contaminations. Our results showed that the intake presented relatively lower concentrations of phos- phorus and nitrogen compared with inflow canals. However, the concentrations of Cr, Ni, Cu, Zn and Pb in the sediments of the intake exceeded the lowest effect level （LEL） values, indicating a potential risk to drinking water resource. In addition, the concentrations of Ni in the sediments of Tianji Canal and Jinshu Canal exceeded the severe effect level （SEL） value. More importantly, the concentrations of Cu in the sediments of Tianji Canal exceeded three times of the SEL value. Multivariate statistical analysis confirmed that the domestic sewage primarily contributed to the nutrient accumulation, and the leakage of electronic trash dominated the enrichment of metals in the sediments. Taken together, more effort should be made to ensure the security of water resources in Taihu Lake, especially for the treatment of domestic sewage and industrial wastewater.

关键词： drinking water resource nutrients heavy metals sediments Taihu Lake

Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique

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Journal of Environmental Sciences 2013年第8期25卷 1592-1600页

作者： Qin Sun Yifei Chen Di Xu Yan Wang shiming ding Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry of Education College of Environment Hohai University State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.

关键词： diffusive gradients in thin films (DGT) technique zirconium oxide (Zr-oxide) dissolved reactive phosphate (DRP) interference soil water

Speciation of organic phosphorus in a sediment profile of Lake Taihu Ⅱ.Molecular species and their depth attenuation

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Journal of Environmental Sciences 2013年第5期25卷 925-932页

作者： shiming ding Di Xu Xiuling Bai Shuchun Yao Chengxin Fan Chaosheng Zhang State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences College of Environment and Planning Henan University GIS Centre Ryan Institute and School of Geography and ArchaeologyNational University of IrelandGalwayIreland

The understanding of organic phosphorus（P） dynamics in sediments requires information on their species at the molecular level,but such information in sediment profiles is scarce.A sediment profile was selected from a large eutrophic lake,Lake Taihu（China）,and organic P species in the sediments were detected using solution phosphorus-31 nuclear magnetic resonance spectroscopy（31 P NMR） following extraction of the sediments with a mixture of 0.25 mol/L NaOH and 50 mmol/L EDTA（NaOH-EDTA） *** results showed that P in the NaOH-EDTA extracts was mainly composed of orthophosphate,orthophosphate monoesters,phospholipids,DNA,and *** of the major organic P compound groups and pyrophosphate showed a decreasing trend with the increase of *** half-life times varied from 3 to 27 years,following the order of orthophosphate monoesters 〉 phospholipids DNA 〉 *** component analysis revealed that the detected organic P species had binding phases similar to those of humic acid-associated organic P（NaOH-NRP HA）,a labile organic P pool that tends to transform to recalcitrant organic P pools as the early diagenetic processes *** demonstrated that the depth attenuation of the organic P species could be partly attributed to their increasing immobilization by the sediment solids,while their degradation rates should be significantly lower than what were suggested in previous studies.

关键词： organic phosphorus sediment half-life time 31 P NMR Lake Taihu

Speciation of organic phosphorus in a sediment profile of Lake Taihu I:Chemical forms and their transformation

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Journal of Environmental Sciences 2013年第4期25卷 637-644页

作者： Di Xu shiming ding Bin Li Xiuling Bai Chengxin Fan Chaosheng Zhang State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences College of Forest Resources and Environment Nanjing Forestry University College of Environment and Planning Henan University GIS Centre Ryan Institute and School of Geography and ArchaeologyNational University of IrelandGalwayIreland

Organic phosphorus （nonreactive E NRP） is a major component of P in sediments, but information about its chemical forms and dynamic transformation is limited. The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Talhu, a freshwater and eutrophic lake in China, were investigated. Five forms of NRP in the sediments were extracted based on a chemical fractionation technique, including easily labile NRP （NaHCO3-NRP）, reactive metal oxide-bound NRP （HCl-NRP）, humic acid-associated NRP （NaOH-NRPnA）, fulvic acid-associated NRP （NaOH-NRPFA） and residual NRP （Res-TP）. There were notable transformations with increasing sediment depth from the labile NaHCOa-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools, which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded. Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP. The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments.

关键词： organic phosphorus fractionation transformation Lake Taihu sediment

Significance of dredging on sediment denitrification in Meiliang Bay,China:A year long simulation study

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Journal of Environmental Sciences 2010年第1期22卷 68-75页

作者： Jicheng Zhong Chengxin Fan Lu Zhang Edward Hall shiming ding Bao Li Guofeng Liu State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Department of Freshwater Ecology University of Vienna Althanstr 14A-1090 Vienna Austria

An experiment for studying the effects of sediment dredging on denitrification in sediments was carried out through a one-year incubation of undredged （control） and dredged cores in laboratory. Dredging the upper 30 cm of sediment can significantly affect physico-chemical characteristics of sediments. Less degradation of organic matter in the dredged sediments was found during the experiment. Denitrification rates in the sediments were estimated by the acetylene blockage technique, and ranged from 21.6 to 102.7 nmol N2/（g dry weight （dw）-hr） for the undredged sediment and from 6.9 to 26.9 nmol N2/（g dw-hr） for dredged sediments. The denitrification rates in the undredged sediments were markedly higher （p 〈 0.05） than those in the dredged sediments throughout the incubation, with the exception of February 2006. The importance of various environmental factors on denitrification was assessed, which indicated that denitrification was regulated by temperature. Nitrate was probably the key factor limiting denitrification in both undredged and dredged sediments. Organic carbon played some role in determining the denitrification rates in the dredged sediments, but not in the undredged sediments. Sediment dredging influenced the mineralization of organic matter and denitrification in the sediment; and therefore changed the pattern of inherent cycling of nitrogen.

关键词： sediment dredging denitrification Taihu Lake

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F4人字齿轮减速机轴承失效分析及改进

机械工程师 2024年第2期 8-10,14页

作者：贾锋丁仕明宋汉雄杜宇辉杜树滨河钢集团唐钢公司河北唐山063000

针对国内某2050热轧生产线,F4人字齿轮减速机用调心滚子轴承多次发生保持架断裂的问题,对保持架失效的情况进行了介绍。分析了保持架失效的原因,认为减速机高速轴轴向窜动量大,轴承外圈在偏心套内游动不良,引起两列滚动体受载不均,次承... 详细信息

针对国内某2050热轧生产线,F4人字齿轮减速机用调心滚子轴承多次发生保持架断裂的问题,对保持架失效的情况进行了介绍。分析了保持架失效的原因,认为减速机高速轴轴向窜动量大,轴承外圈在偏心套内游动不良,引起两列滚动体受载不均,次承载列的滚动体对保持架产生额外冲击载荷,造成保持架疲劳断裂。采取了优化偏心套设计、改进轴承结构等措施,提高了轴承使用寿命。

关键词：人字齿轮调心滚子轴承保持架单列受载轴向位移

Stoichiometric NbTiAl_3 (γ1 Phase) Alloy in Ti-Al-Nb Ternary System

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Journal of Materials Science & Technology 1996年第6期12卷 464-466页

作者： Jingxia CAO Jinjun ding and shiming HAO (Dept. of Materials Science and Technology, Northeastern University Shenyang 110006, China)(To whom correspondence should be addressed)Guoliang CHEN (Dept. of Materials Science and Technology University of Science Dept. of Materials Science and Technology Northeastern University Shenyang 110006 China Dept. of Materials Science and Technology University of Science and Technology Beijing Beijing 100083 China

The microstructure and phase constitution in stoichiometric NbTiAl3 (γ1 phase) alloy treated at 1000℃ were examined by metallography and X-ray diffraction. The alloy microstructure is mainly γ1 phase containing η second phase [(Ti,Nb)Al3] less than 1%. DTA analysis shows no phase transformation from room temperature to 1200℃. In the diffusion couple of NbTiAl3 with 7-TiAl compound, clear phase boundary and composition jump exist between γ1 and γ *** results further confirm the existence of γ1 single phase at 1000℃ in Ti-Al-Nb ternary system.

关键词： Ti Stoichiometric NbTiAl3 Alloy in Ti-Al-Nb Ternary System Phase

霍甫水丝蚓(Limnodrilus hoffmeisteri)扰动下沉积物-水界面pH值的二维、高分辨分布特征

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湖泊科学 2016年第1期28卷 156-162页

作者：姚磊韩超丁士明中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室南京210008 中国科学院大学北京100049

采用平面光电极技术研究了霍甫水丝蚓(Limnodrilus hoffmeisteri)扰动对湖泊沉积物-水界面二维pH值分布特征的影响.结果表明水丝蚓扰动能将沉积物-水界面处pH值的变化梯度由2.5 mm内降低1.6个pH值单位减缓至约1 cm内降低0.6个pH值单位,... 详细信息

采用平面光电极技术研究了霍甫水丝蚓(Limnodrilus hoffmeisteri)扰动对湖泊沉积物-水界面二维pH值分布特征的影响.结果表明水丝蚓扰动能将沉积物-水界面处pH值的变化梯度由2.5 mm内降低1.6个pH值单位减缓至约1 cm内降低0.6个pH值单位,并在界面处形成约1 cm深的pH值缓冲区域.水丝蚓的造穴活动也会对沉积物的二维pH值分布产生影响,洞穴内的pH值高于洞穴周边沉积物约0.6个pH值单位.

关键词：二维分布 pH值平面光电极生物扰动霍甫水丝蚓

太湖梅梁湾沉积物中氮铁硫转化细菌的毫米级垂向分布及对氮磷迁移转化的潜在影响

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湖泊科学 2023年第3期35卷 854-862页

作者：范献方高帅帅丁士明中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室南京210008 湖南省微生物研究院长沙410009

本研究在太湖梅梁湾采集沉积柱,采用一种自制的毫米级柱状沉积物自动垂向分层切割装置对表层50 mm沉积物进行垂向切割(间隔2 mm),结合高通量测序技术分析沉积物中细菌群落的毫米级垂向分布;同时采用毫米级高分辨透析技术和薄膜扩散梯度... 详细信息

本研究在太湖梅梁湾采集沉积柱,采用一种自制的毫米级柱状沉积物自动垂向分层切割装置对表层50 mm沉积物进行垂向切割(间隔2 mm),结合高通量测序技术分析沉积物中细菌群落的毫米级垂向分布;同时采用毫米级高分辨透析技术和薄膜扩散梯度技术(DGT)分析溶解态和DGT可获取态铵态氮(NH_(4)^(+)-N)、硝态氮(NO_(3)^(-)-N)、Fe、P的垂向分布特征。结果显示,沉积物中细菌群落与溶解态和DGT可获取态氮铁磷浓度在垂向上呈现显著的异质性。细菌硝酸盐还原主要发生在-16~0 mm沉积物深度,这可能导致了溶解态和DGT可获取态NO_(3)^(-)-N含量在该沉积物深度的明显减少。细菌铁还原主要分布在-32~-18 mm沉积物深度,细菌硫酸盐还原主要分布在-50~-34 mm的沉积物深度;细菌硫酸盐还原是导致沉积物溶解态和DGT可获取态铁磷浓度从-32 mm随沉积物的深度增加而显著增加的主要原因。本研究加深了对富营养化湖泊沉积物中细菌影响氮磷在垂向上迁移转化的认识。

关键词：毫米级垂向分布细菌太湖沉积物氮磷高分辨透析技术薄膜扩散梯度技术