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1.
澜沧江-湄公河重金属污染评价及大坝影响(英文)   总被引:1,自引:1,他引:0  
The resource development and changes of hydrological regime,sediment and water quality in the Mekong River basin have attracted great attentions.This research aimed to enhance the study on transboundary pollution of heavy metals in this international river.In this study,eight sampling sites were selected to collect the bed sand samples along the mainstream of the Mekong River.In addition,the contents of 5 heavy metal elements and their spatial variability along the mainstream of the river were analyzed.The geoaccumulation index(I geo) and potential ecological risk analysis were employed to assess heavy metal pollution status in the mainstream of the Mekong River.The results show that the average content of the heavy metal elements Zn is 91.43 mg/kg,Pb is 41.85 mg/kg,and As is 21.84 mg/kg in the bed sands of the Upper Mekong River,which are higher than those(Zn 68.17 mg/kg,Pb 28.22 mg/kg,As 14.97 mg/kg) in the Lower Mekong.The average content of Cr in the Lower Mekong is 418.86 mg/kg,higher than that in the Upper Mekong(42.19 mg/kg).Luang Prabang has a very high Cr concentration with 762.93 mg/kg and Pakse with 422.90 mg/kg.The concentration of Cu in all of the 8 sampling sites is similar,except for in Jiajiu with 11.70 mg/kg and Jiebei with 7.00 mg/kg.The results of the geoaccumulation index reveal that contaminations caused by Zn and Pb while Pb and As are more than those by Zn in Upper Mekong.Cr is the primary pollutant in the Lower Mekong,especially at Luang Prabang and Pakse.Slight pollution with As also occurs in Pakse.The potential ecological risk index indicates that the potential ecological risk of heavy metals in the mainstream of the Mekong River is low.We argue that the pollution of water quality and contamination of heavy metals in bed sediment caused by mining of mineral resources or geochemical background values in the Mekong is not transmitted from the Upper to the Lower Mekong because of the reservoir sedimentation and dilution along the river.  相似文献   

2.
黄河内蒙古河段冲淤演变及其影响因素(英文)   总被引:3,自引:2,他引:3  
Rivers with fluvial equilibrium are characterized by bed deformation adjustment. The erosion-deposition area in cross-section reflects this characteristic, which is a base of researching the river scour and deposition evolution by time series analysis. With an erosion-deposition area indicator method proposed in this paper, the time series of erosion-deposition area quantity at Bygl and Shhk stations were obtained with the series duration of 31 years from 1976 to 2006. After analysis of its trend and mutation, three different ten- dencies about the evolution were observed in general from the quasi-equilibrium phase through a rapid shrinkage to the final new quasi-equilibrium. It is also found that the trend of erosion-deposition area series will change once a big flood occurred in some of the tributaries, and its ever greater influence is due to the decrease of deluge with the completion of upstream reservoirs. Almost all the turning points were coincident with the time when hyper-concentrated sediment flood occurred in some tributaries. With the time series of clear mutations since the late 1990s, the Inner Mongolian Reach has been in a new equilibrium phase. This can be concluded in two aspects. 1. The absence of big floods and sediment transportation from tributaries result in the river shrinkage, and to regain the channel flow-carrying capacity in Inner Mongolian Reach a large flood is needed both of high peak discharge and of lengthy interval to destroy the new equilibrium. 2. The proposed method of erosion-deposition area indicator is of great help to channel scoureposition evolution analysis because it can demonstrate real time deformation of cross section in quantity.  相似文献   

3.
According to the highway data and some socioeconomic data of 1990, 1994, 2000, 2005 and 2009 of county units in the Pearl River Delta, this paper measured urban integrated power of different counties in different years by factor analysis, and estimated each county’s potential in each year by means of expanded potential model. Based on that, the spatio-temporal association patterns and evolution of county potential were analyzed using spatio-temporal autocorrelation methods, and the validity of spatio-temporal association patterns was verified by comparing with spatial association patterns and cross-correlation function. The main results are shown as follows:(1) The global spatio-temporal association of county potential showed a positive effect during the study period. But this positive effect was not strong, and it had been slowly strengthened during 1994–2005 and decayed during 2005–2009. The local spatio-temporal association characteristics of most counties’ potential kept relatively stable and focused on a positive autocorrelation, however, there were obvious transformations in some counties among four types of local spatio-temporal association(i.e., HH, LL, HL and LH).(2) The distribution difference and its change of local spatio-temporal association types of county potential were obvious. Spatio-temporal HH type units were located in the central zone and Shenzhen-Dongguan region of the eastern zone, but the central spatio-temporal HH area shrunk to the Guangzhou-Foshan core metropolitan region only after 2000; the spatio-temporal LL area in the western zone kept relatively stable with a surface-shaped continuous distribution pattern, new LL type units emerged in the south-central zone since 2005, the eastern LL area expanded during 1994–2000, but then gradually shrunk and scattered at the eastern edge in 2009; the spatio-temporal HL and LH areas varied significantly.(3) The local spatio-temporal association patterns of county potential among the three zones presented significant disparity, and obvious difference between the eastern and central zones tended to decrease, whereas that between the western zone and the central and eastern zones further expanded.(4) Spatio-temporal autocorrelation methods can efficiently mine the spatio-temporal association patterns of county potential, and can better reveal the complicated spatio-temporal interaction between counties than ESDA methods.  相似文献   

4.
熵视角下的广州城市生态系统可持续发展能力分析(英文)   总被引:1,自引:0,他引:1  
The urban ecosystem possesses dissipating structures that can absorb substances and energy from the external environment and export products and wastes to maintain order within the system. Given these circumstances, this paper analyzed the ability of the urban ecosystem in Guangzhou City to sustain development from the perspective of entropy. The research was carried out in three steps. First, an evaluation index system that considers the ability of the urban ecosystem for sustainable development was formed based on the structures and functions of the urban ecosystem and the change in the entropy of the urban socioeconomic ecosystem. Second, the sustainable development ability assessment model for the urban ecosystem was built using information entropy. Last, by combining the time series variation of the evaluation indicators with the entropy weights, this paper analyzed the influence of the combined factors on the sustainable development ability of the urban ecosystem in Guangzhou and suggested some measures to promote the sustainable development of the urban ecosystem in Guangzhou. The conclusions of this study can be summarized as follows: (1) The urban ecosystem has developed in an orderly and healthy direction, with effective control over the urban environmental pollution problems in Guangzhou between 2004 and 2010. (2) The sustainable development ability of the urban ecosystem had been on an upward trend in Guangzhou during the study period. The ability of the natural urban ecosystem to support the urban socioeconomic ecosystem increased continuously, and the improved ecoenvironment enhanced the harmony and vitality of the urban ecosystem in Guangzhou.  相似文献   

5.
京津唐城市群不透水地表增长对水环境的影响(英文)   总被引:4,自引:1,他引:4  
The impervious surface area (ISA) at the regional scale is one of the important en-vironmental factors for examining the interaction and mechanism of Land Use/Cover Change (LUCC)-ecosystem processes-climate change under the interactions of urbanization and global environmental change. Timely and accurate extraction of ISA from remotely sensed data at the regional scale is challenging. This study explored the ISA extraction based on MODIS and DMSP-OLS data and the incorporation of China’s land use/cover data. ISA datasets in Beijing-Tianjin-Tangshan Metropolitan Area (BTTMA) in 2000 and 2008 at a spa-tial resolution of 250 m were developed, their spatiotemporal changes were analyzed, and their impacts on water quality were then evaluated. The results indicated that ISA in BTTMA increased rapidly along urban fringe, transportation corridors and coastal belt both in intensity and extents from 2000 to 2008. Three cities (Tangshan, Langfang and Qinhuangdao) in Hebei Province had higher ISA growth rates than Beijing due to the pressure of population-re?sour?ces-envi?ronments in the city resulting in increasingly transferring industries to the nearby areas. The dense ISA distribution in BTTMA has serious impacts on water quality in the Haihe River watershed. Meanwhile, the proportion of ISA in sub-watersheds has significantly linear relationships with the densities of river COD and NH3-N.  相似文献   

6.
黄河源区径流对气候变化的响应及未来趋势(英文)   总被引:3,自引:1,他引:3  
This study examines the hydrological and meteorological data of the source region of the Yellow River from 1956 to 2010 and future climate scenarios from regional climate model (PRECIS) during 2010-2020. Through analyzing the flow variations and revealing the climate causes, it predicts the variation trend for future flows. It is found that the annual mean flow showed a decreasing trend in recent 50 years in the source region of the Yellow River with quasi-periods of 5a, 8a, 15a, 22a and 42a; the weakened South China Sea summer monsoon induced precipitation decrease, as well as evaporation increase and frozen soil degeneration in the scenario of global warming are the climate factors, which have caused flow decrease. Based on the regional climate model PRECIS prediction, the flows in the source region of the Yellow River are likely to decrease generally in the next 20 years.  相似文献   

7.
Palaeo-hydrological field investigation was carried out in the middle reaches of the Jinghe River. A set of palaeoflood slackwater deposit beds was identified in the Holocene loess-soil sequence in the riverbanks. The sediment samples were collected from the profile, and the particle-size distribution, magnetic susceptibility, loss-on-ignition were analyzed in laboratory. The analytical results showed that the palaeoflood slackwater deposits have re-corded extraordinary flood events in the Jinghe River valley. According to stratigraphic cor-relation and OSL dating, the palaeoflood events were dated to 4100-4000 a BP. The pa-laeoflood peak discharges were estimated to be 19,410-22,280 m3/s by using the hydro-logical model and checked by different approaches. These results have the flood data se-quence of the Jinghe River extended to 10,000-year time-scale. It provided significant data for hydraulic engineering and for mitigation of flood hazards in the Jinghe River drainage basin.  相似文献   

8.
Understanding the Changing Planet: Strategic Directions for the Geographical Sciences(UCP),published by the National Research Council(USA),and its comments in The Professional Geographer propose that uppercase and plural "Geographical Sciences"(GS) is the strategic direction for geography in the next decade for better understanding of our rapidly changing planet. According to these comments,UCP valued technologies and tools excessively("task"),and did not pay much attention to methodology("discipline"). Actually,both"task" and "discipline" are geographical wings,especially in the time of "big science".Enlightenment from UCP and its comments is the strategic direction that should be balanced between "task" and "discipline",GS should be a three-dimensional construct of a disciplinary system,methodology,and technologies and tools,and this system should be scientific humanism based on scientific spirit and directed by humanism. During the last 60 years,Chinese geographers devoted themselves to GS,including practice and theory. Obviously progress and outlook are proposed as interdisciplinary GS,Earth Surface Sciences(ESS) and Geographical Construction(GC). The disciplinary system of GS is very complex,and is composed of such human knowledge domains as sciences,technologies,engineering,and philosophy. The main mission is to research the open,complex,and macro earth system(not only scientifically,but also humanistically),and one significant methodology is "comprehensive integration of qualitative and quantitative means"(CIQQM). At the same time,another changing direction in Chinese geography is Human-Economic Geography(HEG).  相似文献   

9.
塔里木河流域绿洲城镇发展与水土资源效益分析(英文)   总被引:3,自引:1,他引:3  
This paper examines the spatial pattern of land and water resources as well as urbanization and their interactions in the Tarim River Basin, Xinjiang, China. In order to do so, we extract the data associated with efficiency of land and water resources and urbanization for the years of 1995, 2000, 2005 and 2008. Specifically the paper investigates the extent to which agglomeration of population and economic activities varies geographically and interplays with spatial pattern of resources efficiency through computation of Global Moran’s I index, Getis-Ord Gi* index and a coordinated development model. The method used provides clear evidence that urbanization, land and water resources efficiency have shown uneven spatial pattern due to oasis distribution, climate, and initial phase of urban development. Some conclusions can be drawn as follows.(1) Agglomeration and dispersion of urbanization are not consistent with those of land and water resources efficiency.(2) Evolution of the hot and cold spots of urbanization, and land and water resources efficiency, in different trajectories, indicate that there are no significant interactions between them.(3) The evidence that numbers of hot and cold spots of the three factors present varying structures reveals the dominance of unequal urban development in the study area.(4) Significant differences are also found between sub-river basins in terms of the three factors, which is a reflection of the complex physical geography of the area.(5) The degree of coordinated development of cities in the Tarim River Basin is generally low in part as a reflection of difference in spatial patterns of the three factors. It is also shown that the pattern of the degree of coordinated development is relatively stable compared with evolution of hot and cold spots of the three factors.  相似文献   

10.
The catchment of South Luohe River in Central China is an important region for investigating modern pollen-environment relationship, because it is located in the transitional zone between south and north China, an environment which is sensitive to climate changes. In this study, 40 surface samples under ten vegetation types were collected to reveal the relationship between pollen assemblages and vegetation. The results show that the surface pollen assemblages reflect the vegetation quite well. In forest topsoils, the average of arboreal pollen content is greater than 40%, and the Selaginella sinensis spore is high. As to sparse forest grassland and shrub community, the average arboreal pollen is 13.2% and 16.6% respectively, and the shrub pollen is relatively higher than that of grassland samples. The grassland and farmland are characterized by low percentage of tree and shrub pollen(<10% and <1%), and high percentage of herbs(>80%). Pinus, Quercus and some other arboreal pollen can indicate the regional vegetation because of their dispersal ability. Quercus pollen is under-representative and so is Pinus. Artemisia pollen is significantly over-represented, has poor correlation with the plant coverage, and may reflect human disturbance. Gramineae can indicate plant quite well, but with low representation. High content of Chenopodiaceae probably suggests human impact. Predominant Selaginella sinensis can be used as an indicator of forest environment. Cluster analysis and principal components analysis of pollen assemblages can distinguish forest and non-forest vegetation well. The former method is better at separating pine and mixed forests, while the latter is more stable and could better differentiate farmland and other non-forest area. The first axis of PCA mainly reflects the humidity.  相似文献   

11.
The water quality in the surface microlayer (SML) and subsurface water (SSW) in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were analyzed. The spatial and temporal dynamics of nutrient concentrations, heavy metals and bacteria were examined from two sampling sites in monthly samples throughout 2010. The mean concentrations of total nitrogen, ammonia, nitrate and nitrite were higher than 7.0 mg/L, 3.1 mg/L, 1.1 mg/L and 0.3 mg/L, while total phosphorus and orthophosphate were 0.5 mg/L and 0.1 mg/L, respectively. These results indicated that the water quality was rich in minerals and eutrophic. The mean concentrations of Mn and Fe were higher than 0.013 mg/L; and Ni, Cr and Pb were higher than 0.001 mg/L. The mean concentrations were in the order of Mn >Fe > Ni > Pb > Cr. The concentrations of heavy metals in the Guangzhou segment were lower than the limit of the surface water quality standards in China and the World Health Organization (WHO), but higher than the median values in the world’s freshwater. The density of bacteria ranged from 3.30×105 to 5.23×106 cells/mL, and the amount of cultivable heterotrophic bacteria ranged from 1.30×103 to 1.89×106 cfu/mL. Fecal coliform levels were beyond the V class of China water quality standard. The SML was enriched in nutrients, heavy metals and bacteria, with the maximum enrichment factor of 3.84 for nutrients, 8.00 for heavy metals, and 3.04 for bacteria, suggesting that the water quality of the SML of the Guangzhou segment of the Pearl River was more serious than in the SSW.  相似文献   

12.
宫清华  袁少雄  陈波 《热带地理》2013,33(4):394-399
珠江河道广州城区段的演变在广州城市生态环境演变,特别是在城市防洪减灾中起着至关重要的作用。本文融合珠江在广州城区河段(珠江隧道-海印桥)古代、近代、现代的地图资料、遥感资料和文献资料,选取典型断面数据,建立了各断面不同时段的岸线图谱,定量反映珠江该段河道的时空演变特征,根据近年来人类工程活动等相关研究成果,推演珠江河道的演变趋势,分析河道演变对于城市生态环境和城市防洪减灾产生的影响。结果显示:20世纪50年代以前,珠江河道以0.6~0.8m/a的速度逐步缩窄;50年代以后,随着珠江堤围系统的完善,河道平面形态总体趋于稳定,局部断面仍在缩窄,最后讨论珠江河道缩窄对城市洪涝灾害、水环境污染、生物多样性等几个方面的影响。研究成果可为城市发展及水环境保护决策提供理论和现实依据。  相似文献   

13.
以珠三角空间梯度上的核心区广州、近郊区肇庆鼎湖及远郊区怀集三地的葫芦藓为研究对象,对其重金属污染进行研究。结果显示:珠三角地区葫芦藓重金属含量呈明显的梯级分布,其中Cu、Pb、Zn、Cr、Cd含量均表现为广州最高,分别为47.64、68.83、252.87、64.20和1.02mg/kg;肇庆次之,分别为36.34、40.51、143.49、51.29和0.64mg/kg;怀集最低,分别为16.42、11.80、97.13、32.43和0.21mg/kg。珠三角地区葫芦藓内不同重金属的含量差异反映了来源差异,其中Cd、Pb、Zn和Cu之间呈显著正相关关系,反映了重金属元素来自于相同的污染源;而Cr与Cd、Pb、Cu和Zn的相关性相对弱一些,说明Cr的污染源与其他元素存在一些差异,或者说这个元素与其他元素同时污染大气的可能性相对小一些。分析进一步揭示,三地葫芦藓污染同三地大气污染以及工业化进程存在一定的耦合性。基于此,指出葫芦藓可作为研究环境污染的指示标志,具有重要的环境指示意义。  相似文献   

14.
珠江口底质重金属分布特征及其生态危害性评价   总被引:2,自引:0,他引:2  
对珠江口57个表层沉积物的4项重金属元素Cr、Pb、Zn、Cu进行分析,结果表明:其含量分布在珠江口西侧高于东侧,在内伶仃岛以南呈明显的东南向降低趋势;重金属元素与常量元素TiO2、MnO、Fe2O3、P2O5、Al2O3呈正相关,以Fe2O3、P2O5最为显著:与粘土含量也呈正相关.研究结果还表明,底质环境中Cr、Pb、Zn、Cu含量近年来呈增长趋势,存在不同程度的污染,生态危害性大小为Pb>Cu>Cr>Zn,个体和总体危害程度轻微.  相似文献   

15.
喻远 《热带地理》2012,32(1):22-31
在对珠江广州段与东江、西江、北江的部分地段及广州市水务局、猎德污水处理厂、猎德村居民和英国泰晤士河等实地调查、资料分析的基础上,对珠江广州段近年污水治理与泰晤士河伦敦段两次成功治理进行比较、综合分析,提出制度能力对中国水污染治理的作用与意义.制度能力是针对解决某一具体事物而综合相关各个层面因素形成的能力.文中从规划、科研、体制、公众参与、立法五个方面总结了伦敦的经验,以期为广州治水提供借鉴.分析了广州治水过程中的制约因素,包括地方政府权力过大,以GDP为政绩的最主要考核指标,体制上有缺陷(多头管水,各主管  相似文献   

16.
白鹅潭位于广州市区西部,是珠江广州段水最深、河面最阔之处,前、后航道及流溪河交汇的节点,其特殊的地理区位和自然条件对广州市城市发展起着至关重要的作用。文章首先探讨珠江白鹅潭段河段卡口的地质地貌特征,利用近代地图及遥感图等数据,分析白鹅潭的河道演变及冲淤变化。结果表明,白鹅潭卡口河段的控制性作用对珠江水位的稳定具有重要的影响,白鹅潭段河床演变总体特征为河道缩窄较为明显,而淤浅相对较缓,卡口河段束窄,势必影响上游洪水下泄和缩减下游纳潮量。因此为保护珠江和广州城市的安全,应遵从河道演变规律,保证珠江卡口段两岸有较开阔的空间,不应再束窄江面。  相似文献   

17.
Much of the development literature and the theory of urban transition have been based on an arbitrary division of production space into city and countryside. Despite growing recognition of the need for an integrated approach to urban-rural relations, controversial issues related to the definition and measurement of the phenomenon remain unresolved. This case study of spatial transformation in China’s Pearl River Delta analyzes with greater precision the geographic extent and functional attributes of a zone of urban-rural interaction located outside and between major metropolitan centers. This zone has been the spatial focus of industrial and commercial development, although most of its population remains officially classified as “agricultural.” The peri-urban zone was initially left behind by the central cities in terms of its contribution to the regional economy. After a decade of postreform development, this zone has moved ahead of the central cities and become the region’s main destination for in-migrants and foreign investment. The growth of the zone of urban-rural interaction outside the central cities has absorbed a significant amount of the increased urban population, but it has not brought about a reduction of regional economic inequality because of the persistence of a backward economy in the periphery. Theoretical questions are raised concerning the validity of several fundamental assumptions underlying the conventional model of urban transition.  相似文献   

18.
The Pearl River Delta region in south China has experienced dramatic economic development, industrialization and urbanization since the late 1970s. Foreign investment, especially the capital from Hong Kong, has been one of the major driving forces underlying the process. The spatial concentration/diffusion of foreign investment in a region also has important bearing on the balanced/unbalanced urban and regional development. This issue remains unexamined and critical analysis is needed to unveil the spatial impacts of foreign direct investment (FDI) activities in China. This paper will focus on the Pearl River Delta region to examine the spatial diffusion and the determinants of foreign investment. The diffusion of foreign investment from the provincial capital, Guangzhou and two special economic zones near Hong Kong to surrounding areas is clearly identified. The diffusion is the result of the widespread implementation of open-door policy in the region and significant improvement in infrastructure. Four models of foreign investment are developed to explain the spatial incidence of foreign investment in the region. The findings of this paper can shed light on the regional development process in China and other developing countries under the influence of foreign capital.  相似文献   

19.
尺度重组是解释当前国家、城市等地域组织参与全球化竞争的工具媒介。文章以中国华南地区改革开放以来广东、香港、澳门三地跨界合作为例,借鉴行动者网络理论的研究方法深入剖析珠三角、大珠三角及粤港澳大湾区3个“新国家空间”的尺度重组过程,揭示中国尺度重组的政治经济逻辑。研究发现,行动者拥有的资源决定了其在尺度网络中的地位,而中国的“新国家空间”形成主要依托中央政府推动,其发展目标的设定具有决定性作用,港澳特区政府、广东省地方政府、乡镇企业和外资企业等其他行动者在协同合作中将自身的发展目标与之融合形成了“强制通过点”。纵观三阶段的演变过程,制度因素的重要性越来越得到凸显。  相似文献   

20.
珠江三角洲城市群大气微生物优势 种群及时空分异特征   总被引:2,自引:0,他引:2  
用JWL-IIB新型固体撞击式多功能空气微生物采集仪,于2005至2007年,分别在春、夏、秋、冬不同的季节,对珠江三角洲8个城市(广州、深圳、珠海、佛山、江门、东莞、惠州、中山)的四个不同的功能区(交通枢纽、商业区步行街、居民区和工业区)161个样点,进行大气微生物采样、测定与时空分布规律初步研究,拟为珠江三角洲城市环境污染的综合防治和卫生防疫工作提供依据。研究结果表明:珠江三角洲城市群大气微生物真菌的优势种群有:曲霉属(Aspergillus)、青霉属(Penicillium)、枝孢属( Cladosporium)、芽枝霉属(Clodosporium)等,共19属21种,细菌的优势种群有芽孢杆菌属(Bacillus)、葡萄球菌属(Staphylococcus)、微小杆菌属(Exiguobacterium)、链霉菌属(Streptomyces)等,共4属15种。大气微生物含量在珠江三角洲城市群中广州和东莞较高,细菌比真菌含量高;室内较室外高,无绿化地较有绿化地高,大气微生物含量在全年中,春、夏季相对较高。  相似文献   

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