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1Rare earth elements:A review of applications, occurrence,exploration,analysis,recycling, and environmental impact显示文摘Rare earth elements(REE)include the lanthanide series elements(La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy.Ho,Er,Tm,Yb,and Lu)plus Sc and Y.Currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to LED light bulbs and wind turbines.This article summarizes the occurrence of these metals in the Earth’s crust,their mineralogy,different types of deposits both on land and oceans from the standpoint of the new data with more examples from the Indian subcontinent.In addition to their utility to understand the formation of the major Earth reservoirs.multi-faceted updates on the applications of REE in agriculture and medicine including new emerging ones are presented.Environmental hazards including human health issues due to REE mining and large-scale dumping of e-waste containing significant concentrations of REE are summarized.New strategies for the future supply of REE including recent developments in the extraction of REE from coal fired ash and recycling from e-waste are presented.Recent developments in individual REE separation technologies in both metallurgical and recycling operations have been highlighted.An outline of the analytical methods for their precise and accurate determinations required in all these studies,such as,Xray fluorescence spectrometry(XRF),laser induced breakdown spectroscopy(LIBS),instrumental neutron activation analysis(INAA),inductively coupled plasma optical emission spectrometry(ICP-OES),glow discharge mass spectrometry(GD-MS),inductively coupled plasma mass spectrometry(including ICP-MS,ICP-TOF-MS,HR-ICP-MS with laser ablation as well as solution nebulization)and other instrumental techniques,in different types of materials are presented.V.Balaram 2019Geoscience Frontiers2019,10,4:42
2Intelligent and ecological coal mining as well as clean utilization technology in China: Review and prospects显示文摘Coal is an essential fossil fuel in China; however, coal mining and its utilization are being under the increasing pressure from ecological and environmental protection. Therefore, the consulting project 'Technical Revolution in Ecological and Efficient Coal Mining and Utilization & Intelligence and Diverse Coordination of Coal-based Energy System,' initiated by Chinese Academy of Engineering, puts forward three stages(3.0, 4.0 and 5.0) of China's coal industry development strategy. Aimed at 'reduced staff,ultra-low ecological damage, and emission level near to natural gas,' breakthroughs should be achieved in the following three key technologies during the China Coal Industry 3.0 stage(2016–2025): including intelligent coal mining, ecological mining, ultra-low emission and environmental protection. This paper focuses on the development trends of the China Coal Industry 3.0 and its support for China Coal Industry 4.0 and 5.0 is analyzed and prospected as well, which may offer technical assistance and strategy orientation for realizing the transformation from traditional coal energy to clean energy.Guofa Wang Yongxiang Xu Huaiwei Ren 2019International Journal of Mining Science and Technology2019,29,2:37
3A study of interaction between surface water and groundwater using environmental isotope in Huaisha River basin显示文摘The surface water and groundwater are important components of water cycle, and the interaction between surface water and groundwater is the important part in water cycle research. As the effective tracers in water cycle research, environmental isotope and hydrochemistry can reveal the interrelationships between surface water and groundwater effectively. The study area is the Huaisha River basin, which is located in Huairou district, Beijing. The field surveying and sampling for spring, river and well water were finished in 2002 and 2003. The hydrogen and oxygen isotopes and water quality were measured at the laboratory. The spatial characteristics in isotope and evolution of water quality along river lines at the different area were analyzed. The altitude effect of oxygen isotope in springs was revealed, and then using this equation, theory foundation for deducing recharge source of spring was estimated. By applying the mass balance method, the annual mean groundwater recharge rate at the catchment was estimated. Based on the groundwater recharge analysis, combining the hydrogeological condition analysis, and comparing the rainfall-runoff coefficients from the 1960s to 1990s in the Huaisha River basin and those in the Chaobai River basin, part of the runoff in the Huaisha River basin is recharged outside of this basin, in other words, this basin is an un-enclosed basin. On the basis of synthetically analyses, combining the compositions of hydrogen and oxygen isotopes and hydrochemistry, geomorphology, geology, and watershed systems characteristics, the relative contributions between surface water and groundwater flow at the different areas at the catchments were evaluated, and the interaction between surface water and groundwater was re- vealed lastly.SONG Xianfang1, LIU Xiangchao1, 2, XIA Jun1, YU Jingjie1 & TANG Changyuan1, 3 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Re- sources Research, Chinese Academy of Sciences, Beijing 100101, China 2. College of River and Ocean, Chongqing Jiaotong University, Chongqing 400074, China 3. Chiba University, Chiba 263-8522, Japan 2006Science China Earth Sciences2006,49,12:34
4Oxygen and carbon isotopic characteristics of rainwater,drip water and present speleothems in a cave in Guilin area,and their environmental meanings显示文摘The studies of the oxgen and carbon isotopes of the rainwater in Guilin area, the drip water and the present carbonate deposit in Panlong cave of Guilin show that: (i) as to the general characteristics of the oxygen isotopes of the rainwater within a year and between years, the δ18O values decrease with an increase of air temperature and the rainfall, and the correlation betweenδ18O values and the mean monthly air temperature is much better than that between δ18O values and the rainfall, and the δ18O values of the rainwater during the summer monsoon are much smaller than those during winter monsoon; (ii) δ18O values of the drip water have a quite good correlation with the δ18O values of the rainwater in the same period; (iii) when the conditions are appropriate, δ13C can be used as an environmental proxy, that is, the smaller δ13C of speleothems is, the larger the proportion of C3 plants is and the more plentiful the rainfall is. On the contrary, C4 plants may be prevailing or the environment李彬 袁道先 覃嘉铭 林玉石 张美良 2000Science China Earth Sciences2000,43,3:31
5湖泊水动力模型外部输入条件不确定性和敏感性分析显示文摘以我国典型的大型浅水湖泊太湖为研究区域,采用国内外常用的环境流体动力学模型(EFDC),结合拉丁超立方取样(LHS)方法,研究湖泊水动力模型中4个重要的外部输入条件,即3个边界输入条件(出入湖流量、风速、风向)和1个初始输入条件(初始水位),对模型水动力模拟结果(水位、水龄以及流场)的影响与贡献.结果表明,初始水位的设定对模拟全湖水位和水龄产生决定性影响,不确定性的贡献率分别达到85.73%.和1166.125%,对垂向平均流速影响的贡献率只有3%;风速对表面流速模拟结果影响较大,贡献率达到58.70%,而对水位和水龄的贡献率分别为5.25%和3.00%.在垂向上,各层流速受外部输入条件不确定性的影响规律相似,贡献率排序为风速(55%-60%)〉风向(10%-15%)〉初始水位≈出入湖流量(1%~5%).因此在模拟大型浅水湖泊水动力过程时,可以根据不同的输出目标能够有针对性地提高外部输入条件的准确度,为提高模型精确度提供有效信息.李一平 邱利 唐春燕 布旻晟 田威 余钟波 Kumud Acharya 2014中国环境科学2014,34,2:30
6Environmental records of lacustrine sediments in different time scales:Sediment grain size as an example显示文摘Sediment grain size is a conventional proxy of climatic changes. Larger sediment grain size is often interpreted to indicate dry climate during lower lake level while smaller sedi- ment grain size implies wet climate during higher lake level. Through detailed study on sediment grain sizes in Lake Erhai and Lake Chenghai, this paper reveals the different indication signifi- cances of sediment grain sizes in different time scales, different resolution investigations. For long time-scale and low resolution (102a or 103a) studies, larger sediment grain size indicates lower lake level, smaller lake area and drier climate while smaller sediment grain size indicates higher lake level, larger lake area and wetter climate. For short time-scale and high resolution (a or 10a) studies, larger sediment grain size reflects more rainfall and wetter climate while smaller sediment grain size reflects less rainfall and drier climate. Environmental information revealed by lacustrine sediment records is often different in different time scales because of the variance of sedimentation resolution, sampling resolution and dating precision. Therefore, paleoclimate im- plications of environmental proxies in long time-scale and low resolution investigations could not be mechanically applied to short time-scale and high resolution studies. Only after synthetically analyzing the influence manner and extent of all factors on the sediment records in different time scales, can credible conclusions be obtained.CHEN Jing’an1, WAN Guojiang1, David Dian Zhang2, ZHANG Feng1 & HUANG Ronggui1 1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China 2. Department of Geography and Geology, University of Hong Kong, Pokfulam Road, Hong Kong, China 2004Science China Earth Sciences2004,47,10:27
7Two pedogenic models for paleoclimatic records of magnetic susceptibility from Chinese and Siberian loess显示文摘The magnetic susceptibility (MS) of Chinese loess showing a general proportional relationship to pedogenic grade has been widely recognized and used for reconstruction of paleoclimate by Quaternary scientists. The in-situ pedogenic enhancement of ferrimagnetic content is normally believed to be the main reason for the increase of susceptibility in soil units. However, this pattern of high magnetic susceptibility in palaeosols, and low values in loess, are not replicated in some loess deposits. Siberian loess deposits display a completely opposite susceptibility behavior: high values in loess and low values in palaeosols. This inverse relationship has been explained by the idea that magnetic susceptibility is reflecting the magnitude of an aeolian ferrimagnetic component of consistent mineralogy, the grain size of which is related to average wind velocity. Our magnetic study of Siberian samples in this paper suggests that there are notable differences in magnetic properties between Siberian loess and developed palaeosols, not only in magnetic grain-size and concentration but also in magnetic mineralogy. This evidence is difficult to explain fully through variation in wind strength alone, but implies that the low magnetic susceptibility values in the Siberian paleosol units are a reflection, at least in part, of the alteration of the ferrimagnetic content by post-depositional processes. The Loess Plateau is a very arid area where potential evaporation is always higher than precipitation; pedogenesis occurs under dry oxidising conditions. The Siberian Kurtak region is located on the edge of the tundra where it is always wet and saturation during interglacials will lead to a reducing pedogenic environment. Ferrimagnetic minerals under this condition will be destroyed, resulting in lower magnetic susceptibility. Therefore, great care should be taken when using susceptibility values for paleoclimatic reconstruction.Paul HESSE Jiri CHLACHULA 2008Science China Earth Sciences2008,51,2:25
8New progress of lake sediments and environmental changes research in China显示文摘Environmental change recorded by lake sediments is one of the important branches of the past global changes study. The new progress of lake sediments and environmental changes in China since the late 1980s has been comprehensively discussed. The highlights emphasized are Asian paleomonsoon migration reflected by lake level fluctuation, uplift of the Qinghai-Xizang Plateau recorded by lacustrine sediments, saltlake sediments andWANG Sumin and ZHANG ZhenkeLaboratory of Lake Sediment and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008, China Department of Geography and Oceanology, Nanjing University , Nanjing 210093 , China 1999Chinese Science Bulletin1999,44,19:22
92000-2015年中国PM_(2.5)时空演化特征及驱动因素解析(英文)显示文摘High concentrations of PM_(2.5) are universally considered as a main cause for haze formation. Therefore, it is important to identify the spatial heterogeneity and influencing factors of PM_(2.5) concentrations for regional air quality control and management. In this study, PM_(2.5) data from 2000 to 2015 was determined from an inversion of NASA atmospheric remote sensing images. Using geo-statistics, geographic detectors, and geo-spatial analysis methods, the spatio-temporal evolution patterns and driving factors of PM_(2.5) concentration in China were evaluated. The main results are as follows.(1) In general, the average concentration of PM_(2.5) in China increased quickly and reached its peak value in 2006; subsequently, concentrations remained between 21.84 and 35.08 μg/m3.(2) PM_(2.5) is strikingly heterogeneous in China, with higher concentrations in the north and east than in the south and west. In particular, areas with relatively high PM_(2.5) concentrations are primarily in four regions, the Huang-Huai-Hai Plain, Lower Yangtze River Delta Plain, Sichuan Basin, and Taklimakan Desert. Among them, Beijing-Tianjin-Hebei Region has the highest concentration of PM_(2.5).(3) The center of gravity of PM_(2.5) has generally moved northeastward, which indicates an increasingly serious haze in eastern China. High-value PM_(2.5) concentrations have moved eastward, while low-value PM_(2.5) has moved westward.(4) Spatial autocorrelation analysis indicates a significantly positive spatial correlation. The 'High-High' PM_(2.5) agglomeration areas are distributed in the Huang-Huai-Hai Plain, Fenhe-Weihe River Basin, Sichuan Basin, and Jianghan Plain regions. The 'Low-Low' PM_(2.5) agglomeration areas include Inner Mongolia and Heilongjiang, north of the Great Wall, Qinghai-Tibet Plateau, and Taiwan, Hainan, and Fujian and other southeast coastal cities and islands.(5) Geographic detection analysis indicates that both natural and anthropogenic factors account for spatial variations in PM_(2.5) concentration. Geographical location, population density, automobile quantity, industrial discharge, and straw burning are the main driving forces of PM_(2.5) concentration in China.周亮 周成虎 杨帆 车磊 王波 孙东琪 2019Journal of Geographical Sciences2019,29,2:22
10Cancer prevention and control: alarming challenges in China显示文摘China is geographically the third largest country in the world and the most populated low-to-middle-income country. Cancer incidence and mortality rates for some cancers in the USA and European countries have steadily decreased over the last decades, whereas the incidence and mortality of certain cancers in China have been increasing at an alarming speed. Rapid industrialization and urbanization in China have been accompanied by incredible changes in lifestyle and environment combined with an aging population. Mortality caused by lung, colorectal and breast cancers has been steadily increasing, whereas cancer mortality from gastric, esophageal and cervical tumors has tended to decrease. Similar to what has occurred in the United States, unhealthy lifestyles in China, including heavy smoking and poor diet combined with pollution, have contributed to increased cancer risk. China is facing many challenges in cancer treatment and prevention for the general population. The major areas that need to be addressed in the control of cancer in China include cancers associated with environmental pollution,tobacco use, occupational carcinogens, infection, excessive alcohol consumption, dietary deficiencies and obesity. In this perspective, we review the problems in each area and suggest ideas for future directions in cancer research and strategies and actions to reduce the incidence of cancer in China.Ann M.Bode Zigang Dong Hongyang Wang 2016National Science Review2016,3,1:22
11Hydrogen peroxide homeostasis and signaling in plant cells显示文摘The increases of H2O2 concentrations in plant cells often occur under biotic and abiotic stress conditions (e.g. light, environmental stresses and plant hormone abscisic acid). Atmospheric H2O2 as an ancient signal molecule not only plays the key role in inducing evolution of oxygenic photosynthesis, but also modulates many physiological events, such as stomatal movement, hypersensitive responses, programmed cell death and gene expressions. H2O2 levels in cells must sustain a fine equilibrium between production and scavenging. H2O2 enters cells from the apoplast or generated sources, and in turn is distributed in sub-cellular compartments. H2O2 can modulate the activities of many components in signaling, such as protein phosphatases, protein kinases, transcription factors (TFs), and calcium channels. Elevated cytosolic calcium concentrations will initiate further downstream responses, via the action of calcium-binding proteins. On the other hand, the research of H2O2 as a signal molecule is still in a comparatively juvenile stage, for example, little is known about how the cells sense H2O2, what the rate-limiting steps and most important cellular events are in cell signaling and what kind of genes is specific or necessary to H2O2 signaling. The answers to all the questions depend on the functional genomic and molecular genetics analysis.CHENG Yanli SONG Chunpen 2006Science China(Life Sciences)2006,49,1:21
12Cropland cover change in Northeast China during the past 300 years显示文摘Land use/cover change induced by human activities has emerged as a 'global' phenomenon with Earth system consequences. Northeast China is an area where the largest land cultivation activities by migrants have happened in China during the past 300 years. In this paper, methods including documentary data calibration and multi-sourced data conversion model are used to reconstruct historical cropland cover change in Northeast China during the past 300 years. It is concluded that human beings have remarkably changed the natural landscape of the region by land cultivation in the past 300 years. Cropland area has increased almost exponentially during the past 300 years, especially during the past 100 years when the ratio of cropland cover changed from 10% to 20%. Until the middle of the 19th century, the agricultural area was still mainly restricted in Liaoning Province. From the late 19th century to the early 20th century, dramatic changes took place when the northern boundary of cultivation had extended to the middle of Heilongjiang Province. During the 20th century, three agricultural regions with high ratio of cropland cover were formed after the two phases of spatial expansion of cropland area in 1900s—1930s and 1950s—1980s. Since 1930s—1940s, the expansion of new cultivated area have invaded the forest lands especially in Jilin and Heilongjiang Provinces.YE Yu FANG XiuQi REN YuYu ZHANG XueZhen CHEN Li 2009Science China Earth Sciences2009,52,8:21
13Biomass and carbon dynamics of a tropical mountain rain forest in China显示文摘Biometric inventories for 25 years,from 1983 to 2005,indicated that the Jianfengling tropical mountain rain forest in Hainan,China,was either a source or a modest sink of carbon.Overall,this forest was a small carbon sink with an accumulation rate of(0.56±0.22) Mg C ha-1yr-1,integrated from the long-term measurement data of two plots(P9201 and P8302).These findings were similar to those for African and American rain forests((0.62±0.23) Mg C ha-1yr-1).The carbon density varied between(201.43±29.38) Mg C ha-1 and(229.16±39.2) Mg C ha-1,and averaged(214.17±32.42) Mg C ha-1 for plot P9201.Plot P8302,however,varied between(223.95±45.92) Mg C ha-1 and(254.85±48.86) Mg C ha-1,and averaged(243.35±47.64) Mg C ha-1.Quadratic relationships were found between the strength of carbon sequestration and heavy rainstorms and dry months.Precipitation and evapotranspiration are two major factors controlling carbon sequestration in the tropical mountain rain forest.CHEN DeXiang1*,LI YiDe1,LIU HePing2,XU Han1,XIAO WenFa3,LUO TuShou1,ZHOU Zhang4 & LIN MingXian1 1Research Institute of Tropical Forestry,Chinese Academy of Forestry,Guangzhou 510520,China 2Department of Physics,Atmospheric Science and Geoscience,Jackson State University,MS 39217,USA 3Research Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,Beijing 100091,China 4Department of Ecology,College of Urban and Environmental Sciences,Peking University,Beijing 100872,China 2010Science China(Life Sciences)2010,53,7:20
14mergy evaluation of the environment and economy of Hong Kong显示文摘EmergyevaluationoftheenvironmentandeconomyofHongKongLanShengfangDepartmentofBiology,SouthChinaAgriculturalUniversity,Guangzho...Lan ShengfangDepartment of Biology, South China Agricultural University,Guangzhou 510642, ChinaHoward T. Odum(Environmental Engineering Sciences , University of Florida .Gainesville, FL 32611 , USA) 1994Journal of Environmental Sciences1994,6,4:20
15Tackling on environmental changes in Tibetan Plateau with focus on water, ecosystem and adaptation显示文摘The Tibetan Plateau represents a unique landform with an average elevation that is higher than 4,000 m above sea level. Also known as the roof of the world and the Asian Water Tower, this topography preserves the largest ice mass as the solid water outside the Arctic and Antarctica. The Tibetan Plateau is a natural laboratory for research on multi-sphere interactions and for the study of humannature relationship. China conducted the first large and longstanding scientific expedition to this area between the 1970s and the 1990s and achieved fruitful scientific results.TANDong Yao 2019Science Bulletin2019,64,7:20
16Leaching ion adsorption rare earth by aluminum sulfate for increasing efficiency and lowering the environmental impact显示文摘The leaching efficiency(LE) of ion adsorption rare earth(IARE) by the sulfate and chloride of ammonium,magnesium and aluminum were comparatively determined using column leaching method. It is found that at equal equivalent concentration of cation, the LE of IARE by aluminum sulfate is the highest, and the zeta potential of clay mineral particles in the tailing is near to zero, which means a lower risk of landslide and pollutant emission. Furthermore, the optimum concentration of aluminum sulfate is determined to be0.02 mol/L, which is much lower than that of ammonium sulfate and magnesium sulfate. To reduce the production cost and environmental impact, we proposed a multi-stage leaching process, which was firstly leaching with ammonium sulfate and then with aluminum sulfate, following by water washing and lime neutralizing. With the ratio of ammonium sulfate to aluminum sulfate varying from 1:0 to 0.5:0.5, the residual ammonium in tailing decreases from 11.2% to 0.6%, however, the LE of RE shows an optimum value at 0.8:0.2. By neutralizing the pH of tailing with lime water to over 6, the ion concentration in water rinsing solution can meet the requirement for water discharge. At the same time, the zeta potential of clay particles is found to be around-5 mV, means a relatively lower risk of landslide. These facts indicate that the LE of IARE can be increased and the danger caused by tailings landslides and pollutant emissions can be reduced by replacing ammonium sulfate with aluminum sulfate as leaching reagent.Lifen Yang Cuicui Li Dashan Wang Fengyang Li Yanzhu Liu Xuezhen Zhou Mingbiao Liu Xiufeng Wang Yongxiu Li 2019Journal of Rare Earths2019,37,4:19
17Preliminary results of environmental monitoring of the natural gas hydrate production test in the South China Sea显示文摘Natural gas hydrate (NGH)is considered as one of the new clean energy sources of the 21st century with the highest potential.The environmental issues of NGH production have attracted the close attention of scientists in various countries.From May 10 to July 9,2017,the first offshore NGH production test in the South China Sea (SCS)was conducted by the China Geological Survey.In addition,environmental security has also been effectively guaranteed via a comprehensive environmental monitoring system built during the NGH production test.The monitoring system considered sea-surface atmosphere methane and carbon dioxide concentrations,dissolved methane in the sea water column,and the seafloor physical oceanography and marine chemistry environment.The whole process was monitored via multiple means, in multiple layers,in all domains,and in real time.After the production test,an environmental investigation was promptly conducted to evaluate the environmental impact of the NGH production test. The monitoring results showed that the dissolved methane concentration in seawater and the near-seabed environment characteristics after the test were consistent with the background values,indicating that the NGH production test did not cause environmental problems such as methane leakage.Jian-liang Ye Xu-wen Qin Hai-jun Qiu Qian-yong Liang Yi-fei Dong Jian-gong Wei Hai-long Lu Jing-an Lu Yao-hong Shi Chao Zhong Zhen Xia 2018China Geology2018,1,2:19
18Magnetic properties of tidal flat sediments of the Yangtze Estuary and its relationship with particle size显示文摘This paper considers the magnetic properties of tidal flat sediments of the Yangtze Estuary and its relationship with particle size. The results indicate that magnetite of multi-domain (MD)/pseudo-single domain (PSD) in size dominates the magnetic properties of the samples. In addition to detrital magnetite, spherical magnetic particles are found in the magnetically strongest sediments near Shidongkou sewage outlet, which are ascribed to the product of industrial pollution. Particle size plays a strong role on the magnetic properties of the sediments. Magnetic susceptibility (c) and saturation isothermal remanent magnetization (SIRM) are positively correlated with the proportion of the fraction of 816 mm. However, magnetic parameters indicating fine-grained ferrimagnetic minerals, e.g. susceptibility of anhysteric remanent magnetization (cARM), are highly correlated with the fine fraction of <4 mm and even the fraction of <32 mm. The results indicate that, when c is used as a proxy for pollutant content, it is necessary to consider the possible influence of particle size on it. Due to the significant relationship between cARM and the fine component proportion, cARM can be applied to the normalization of pollutant content for particle size effect.张卫国 俞立中 2003Science China Earth Sciences2003,46,9:17
19Temporal-spatial variations of euphotic depth of typical lake regions in Lake Taihu and its ecological environmental significance显示文摘By using the data of underwater irradiance measured in the different lake regions of Lake Taihu during 1998-2004 and total suspended solids (TSS), wind speeds of the total 13 stations in typical lake regions during 1993-2003, this paper analyzes the factors of influencing on PAR (pho- tosynthetically available radiation) attenuation, euphotic depth, and presents the temporal and spatial variations of euphotic depth of typical lake regions in Lake Taihu, and the spectral distributions of euphotic depth at station 2. The results show that the concentration of TSS is the most important factor impacting PAR attenuation, followed by chlorophyll a; chromophoric dissolved organic matter (CDOM) has little impact on the PAR euphotic depth. During 1993-2003, the mean yearly PAR eu- photic depths of the typical lake regions ranged from 1.04 to 1.95 m with a mean value of 1.35±0.23 m. The PAR euphotic depth fell into 3 spatial zone types: Type I, the lowest, including the lake center and the inflows of rivers; Type II, intermediate, including Meiliang Bay, Wulihu Lake and Gonghu Bay; Type III, the greatest, including the East Lake Taihu; corresponding mean depths were approximately 1.1, 1.4, 2.0 m, respectively. The seasonal variations of euphotic depths were not quite the same in different lake regions. In the lake center, the mean values of PAR euphotic depth in summer and au- tumn were significantly greater than those in winter and spring; in the Meiliang Bay, winter means were significantly greater than in the other three seasons; in the East Lake Taihu, winter means were significantly less than in the other three seasons. However, no distinct seasonal change was recorded in the Wulihu Lake, Gonghu Bay and the inflows of rivers. The spectral distributions of euphotic depth present a minimal value at the blue light wave band of 400 nm, and a peak at the green light wave band of around 580 nm. In 1998 and 1999, based on the seasonal many-day continuous measure- ments, the PAR euphotic depths at station 2 were recorded 2.00±0.21, 2.52±0.45, 1.58±0.24, 2.00 ±0.15 m in spring, summer, autumn and winter, respectively. The peak value of 440 nm absorbed by phytoplankton corresponded to a euphotic depth of only 0.81-1.47 m (mean 1.07±0.29 m), which was much lower than the mean PAR euphotic depth of 1.98±0.41 m.ZHANG Yunlin1, 2, QIN Boqiang1, HU Weiping1, WANG Sumin1, CHEN Yuwei1 & CHEN Weimin1 1. Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing 210008, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 2006Science China Earth Sciences2006,49,4:16
20Aflatoxins,hepatocellular carcinoma and public health显示文摘Hepatocellular carcinoma(HCC) is one of the leading causes of cancer deaths worldwide,primarily affecting populations in the developing countries.Aflatoxin,a food contaminant produced by the fungi Aspergillus flavus and Aspergillus parasiticus,is a known human carcinogen that has been shown to be a causative agent in the pathogenesis of HCC.Aflatoxin can affect a wide range of food commodities including corns,oilseeds,spices,and tree nuts as well as milk,meat,and dried fruit.Many factors affect the growth of Aspergillus fungi and the level of aflatoxin contamination in food.Drought stress is one of the factors that increase susceptibility of plants to Aspergillus and thus aflatoxin contamination.A recent drought is thought to be responsible for finding of trace amounts of aflatoxin in some of the corn harvested in the United States.Although it's too soon to know whether aflatoxin will be a significant problem,since United States is the world's largest corn producer and exporter,this has raised alarm bells.Strict regulations and testing of finished foods and feeds in the United States should prevent a major health scare,and prevent human exposure to deleterious levels of aflatoxin.Unfortunately,such regulations and testing are not in place in many countries.The purpose of this editorial is to summarize the current knowledge on association of aflatoxin and HCC,encourage future research and draw attention to this global public health issue.Arvin Magnussen Mansour A Parsi 2013World Journal of Gastroenterology2013,19,10:16
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