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    25 September 2007, Volume 62 Issue 9 Previous Issue    Next Issue
    Recommendations of Eutrophication Control of Taihu Lake from an International View
    YU Xiaogan, Josef Nipper, YAN Nailing
    2007, 62 (9):  899-906.  doi: 10.11821/xb200709001
    Abstract ( 527 )   PDF (2801KB) ( 548 )   Save

    Eutrophication of lakes has exerted unfavorable impacts on social and economic development in the lake catchments of China. Much attention should be paid to the urgency of this issue. According to the international experiences, how to control effectively the point and non-point pollution is of highest priority in eutrophication control of lakes. Drinking water safety should be highlighted through enforcing freshwater protection laws. A unified freshwater protection mechanism for the whole catchment should be set up. The important steps are: taking watershed integrated management into account in eutrophication control of lakes, and drawing up a long-term working plan and periodic goals. For the Taihu Lake, we should persist in the control effort and never abandon restoration of its water environment.

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    Discussion and Countermeasur es on Safe Drinking Water in the Rural Areas of China
    DAI Xiangqian,, LIU Changming,, LI Lijuan
    2007, 62 (9):  907-916.  doi: 10.11821/xb200709002
    Abstract ( 648 )   PDF (3009KB) ( 754 )   Save

    This paper analyzed the spatial distribution characteristic of rural residents with unsafe drinking water in China, which was resulted from several factors including natural water quality with excessive drinking water standard, polluted water, water shortage and low insurance probability. Results show that water quality with excessive drinking water standard, including naturally unqualified water quality and man-made pollution, is the biggest problem, and the unsafe population accounts for 70% of the total unsafe population, however, there is a difference of extent in the eastern, central and western parts of China, being 78%, 76% and 58% respectively. The remaining unsafe population is due to deficient water quantity, low insurance probability and inconvenient water taking. The ratio of total unsafe rural population to total rural population in the western, central and eastern parts of China is respectively 40%, 35% and 27%. According to these, we inferred the problems' trait of safe drinking water in different areas. Furthermore, we analyzed the causes which form high-fluorin water, the high-arsenic water and bitter and salty water, and discussed the main factors which influence safe drinking water.

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    Analysis and Strategy of Dr inking Water Pollution Accidents in Recent 20 Year s in China
    LI Lijuan, LIANG Liqiao,, LIU Changming, ZHANG Li,, JIANG Dejuan,, LI Jiuyi
    2007, 62 (9):  917-924.  doi: 10.11821/xb200709003
    Abstract ( 594 )   PDF (3056KB) ( 906 )   Save

    Drinking water safety is a prominent environmental issue facing China since it is related to human health directly. Based on the statistical data from articles, the characteristics and causes of the drinking water pollution accidents and their damage to the human society are analyzed. About 152 typical drinking water pollution accidents which happened in China during the period 1986-2005 were analyzed in this study. The results show that 133 accidents, about 87.5% of the total, occurred during the period 1995-2005, and East China is the area with high frequency where 44 accidents occurred. All pollution accidents are chemical or/and biological, and biological pollution accidents account for 69.1%. As viewed from pollution places, almost half of the accidents occurred in residential areas, next in schools. As viewed from water supply links, pollution of water source is the main reason for accidents which accounts for 56.6% of the total. As viewed from pollution type, pollution from daily life is the main reason which resulted in 65.1% of the total accidents, and then industrial pollution. Drinking water pollution accidents have badly affected residents' normal drinkable water, even led to water-borne diseases breaking out or poisoning. In order to actualize safe drinking water, corresponding strategy is brought forward for defending and treating drinking water pollution accidents.

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    Inter annual and Interdecadal Variations of Soil Temperature over Tibetan Plateau from 1971 to 2005
    HU Jun, DU Jun, BIAN Duo, ZUO Huilin, GE Sang, YANG Yong
    2007, 62 (9):  925-934.  doi: 10.11821/xb200709004
    Abstract ( 642 )   PDF (1938KB) ( 565 )   Save

    The variation trend, abrupt change and anomalous years of annual and seasonal mean soil temperatures at 0.8 m, 1.6 m and 3.2 m over Tibet are investigated in the context of the observational data at 10 stations during the period 1971-2005 using modern statistical diagnostic methods such as the linear trend analysis. The results show that the annual mean soil temperature at 0.8 m decline in Chamdo and Nyingri of Tibet where the reduction rate is 0.15 oC/10a and 0.18 oC/10a respectively, but the increasing trends are observed at the other stations at a rate of (0.19-0.81) oC/10a (except for Tesdang, 99% confidence level). Significant increasing trends of annual mean soil temperature at 1.6 m are found at five stations, with the increasing rate of (0.20-0.60) oC/10a (above 95% confidence level). Also, the increasing trends of annual mean soil temperature at 3.2 m are observed at six stations, with the rate of (0.13-0.52) oC/10a, especially in Lhasa. In the case of 0.8 m soil temperature, the following facts are found as: (1) The increasing trends of seasonal mean soil temperature are observed at most stations, with the most remarkable increasing rate in western and southern Tibet in summer, especially in Sengge Zangbu river basin where the rate is 1.61 oC/10a (99% confidence level); the maximum increasing rate is in northern Tibet in winter. But the decreasing trends of the soil temperature are found in most seasons of eastern Tibet. (2) In terms of interdecadal variations, the annual mean soil temperature increases apparently at most stations of Tibet, however it decreases in Chamdo. (3) The abrupt change of spring and summer mean soil temperature is observed in Sengge Zangbu in 1996 and 1983 respectively. The abrupt change of the annual and seasonal mean soil temperatures happens in Lhasa and Shigatse, the former in the 1980s and the latter in the early 1990s, a sudden change from the colder period to the warmer one. In addition, the abrupt change of summer and autumn mean soil temperature occurs in Nyingri in 1993, indicating a change from the warmer period to the colder one. (4) The annual and seasonal soil temperatures occur in the more anomalous higher temperature years at the end of the 1990s and the first five years of the 2100s in western Tibet, while in the mid-late 1990s in southern Tibet and the first five years of the 2100s in northern Tibet. The more anomalous lower years occur mainly in the 1980s while the anomalous lower years dominate in eastern Tibet.

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    Variation Tr ends of the Freezing and Thawing Index along the Qinghai-Xizang Railway for the Per iod 1966-2004
    JIANG Fengqing, HU Ruji, LI Zhen
    2007, 62 (9):  935-945.  doi: 10.11821/xb200709005
    Abstract ( 705 )   PDF (2341KB) ( 694 )   Save

    Yearly freezing and thawing index for seven main stations along the Qinghai-Xizang Railway were calculated based on daily maximum and minimum temperature records for the period 1966-2004. Statistical characteristics and variations of the annual freezing and thawing index for these stations were outlined. Trends in annual freezing and thawing index for these stations were analyzed using two methods, namely a non-parametric trend test method, i.e. the Mann-Kendall test and a simple linear regression method. The results show that the mean annual freezing index for these stations ranges from 95 to 2300 oC, and the mean annual thawing index ranges from 630 to 3250 oC. The mean annual freezing index of the seven stations exhibited decreasing trends with linear tendencies ranging from -16.6 to -59.1 oC/10a, and the mean annual thawing index of the seven stations showed increasing trends with linear tendencies ranging from 19.83 to 45.6 oC/10a. The results of the MK trend test show that the significant decreasing trends in the annual freezing index for most stations except for Golmud were detected at the 0.05 significant level. The increasing trends in the annual thawing index for four stations except Golmud and Tuotuohe were determined by the MK method at the 0.05 significant level. Golmud was the only station where no significant trends in both the annual freezing and thawing index were found. Results from the simply linear regression method are similar with that from the MK test.

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    Temporo-spatial Distribution of Summer Precipitation over Qinghai-Tibet Plateau during the Last 44 Years
    LU Heli, SHAO Quanqin, LIU Jiyuan, WANG Junbang, CHEN Zhuoqi
    2007, 62 (9):  946-958.  doi: 10.11821/xb200709006
    Abstract ( 755 )   PDF (3765KB) ( 759 )   Save

    The summer day-by-day precipitation data of 97 meteorological sites on the Qinghai-Tibet Plateau from 1961 to 2004 were selected to analyse the temporo-spatial distribution using accumulated variance, correlation analysis, regression analysis, empirical orthogonal function, power spectrum function and spatial analysis tools of GIS. The result showed that summer precipitation occupied a relatively high proportion in the area with less annual precipitation on the Qinghai-Tibet Plateau and the correlation between summer precipitation and annual precipitation was strong. The altitude of these stations or points and summer precipitation slope presented stronger positive correlation below 2000 m, with correlation value up to 0.604 and significance of 0.01. Summer precipitation slopes disparity between the periods 1961-1983 and 1984-2004 at five altitude scopes (2000-2500 m, 2500-3000 m, 3500-4000 m, 4000-4500 m and above 4500 m) were above zero and accounted for 71.4% of the total. Using empirical orthogonal function, summer precipitation could be roughly divided into three precipitation pattern fields: the southeast Plateau pattern field, the northeast Plateau pattern field and the Three Rivers' Headstream Regions pattern field. The former two presented a reverse spatial distribution value from the north to the south and the reversal line is along 35oN. The potential cycles of the three pattern fields were 5.33a, 21.33a and 2.17a respectively, tested by the confidence probability of 90%.

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    Variation of Total Cloud Amount and Its Possible Causes over the Qinghai- Xizang Plateau during 1971-2004
    ZHANG Xueqin, PENG Lili, ZHENG Du, TAO Jie
    2007, 62 (9):  959-969.  doi: 10.11821/xb200709007
    Abstract ( 767 )   PDF (2933KB) ( 738 )   Save

    The Qinghai-Xizang (Tibet) Plateau plays a crucial role in global change and the climate of East Asia. It is indispensable to analyze the characteristic of cloudiness variation over the Plateau, which will promote the understanding of climatic change and of cloud-radiation feedback mechanisms in climate models. With EOF and trend analysis method adopted, the spatio-temporal variation of total cloud amount is analyzed for 75 stations over the Plateau during the period of 1971-2004. Analysis indicates that the distribution of total cloud amount is characterized by remarkable regional features, which decreases from the southeast to the northwest of the Plateau. In addition, the annual and seasonal variation of total cloud amount shows a declining tendency over the past decades. Correlation analysis demonstrates that total cloud amount is negative with sunshine duration and diurnal temperature range (DTR), and is positive with precipitation and relative humidity, respectively. The negative correlation is consistent with the radiative effect of cloud, while the positive correlation between total cloud amount and precipitation is obscured because of topographic factor. Discussion implies that the decrease of total cloud amount is possibly due to the variation of atmospheric aerosol content and ozone concentration over the Plateau, although it is difficult to quantify the driving forcing mechanism up to now.

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    Influence of Intermittent Water Deliveries on the Hydrochemistry of Soil in the Lower Tar im River
    CHEN Yongjin, CHEN Yaning, LI Weihong, LIU Jiazhen, Huang Hui
    2007, 62 (9):  970-980.  doi: 10.11821/xb200709008
    Abstract ( 425 )   PDF (3187KB) ( 536 )   Save

    Based on the data of the groundwater buried depths, the chemical properties, salinity in soil profile and the basic information on each delivery of water collected from the year 2000 to 2006, the variational characteristics of groundwater chemistry and related factors were studied. The results confirmed the three stages of the variations in groundwater chemistry influenced by the intermittent water deliveries. The factors which had close relationships with the variations in groundwater chemistry included the distances of monitoring wells from water channel, the depths of groundwater, water flux in watercourse and the salinities in soils. The relationships between chemical variations and groundwater depths indicated that the water quality was the best with the groundwater ranging from 5 to 6 m. In addition, the constructive species in the study area can survive well with the depth of groundwater varying from 5 to 6 m, so the rational depth of groundwater in the lower Tarim River should be 5-6 m.

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    Source and Distribution of Organic Matter in Seabed Sediments of the Changjiang River Estuary and Its Adjacent Sea Area
    GAO Jianhua, WANG Yaping, PAN Shaoming, ZHANG Rui, LI Jun, BAI Fenglong
    2007, 62 (9):  981-991.  doi: 10.11821/xb200709009
    Abstract ( 661 )   PDF (2461KB) ( 708 )   Save

    In this paper, 34 superficial sediment samples were collected in Changjiang River Estuary and its adjacent sea area. Subsequently, grain size, total organic carbon, total nitrogen, carbon and nitrogen isotope compositions were also analysized. Finally, organic carbon and nitrogen spatial distribution patterns in Changjiang River Estuary and its adjacent sea area were studied; characteristics of stable carbon and nitrogen isotope in seabed sediments and their implications for tracing organic matter source were discussed; and contributions of different organic matter sources in seabed sediment were calculated. The spatial distribution patterns of total organic carbon and total nitrogen show apparent correlation with currents of East China Sea shelf. Corresponding to distributions of these currents, the study area could be divided into four different parts. Total organic carbon, total nitrogen, and organic carbon and nitrogen stable isotope in sediments shows linear correlation with mean grain size, respectively, thus "grain size effect" is an important factor that influences their distributions. C/N ratio can reflect source information of organic matter to a certain degree. In contrast, nitrogen stable isotope shows different spatial distribution patterns with C/N and organic carbon stable isotope, according to their relationships and regional distributions. The highest contribution (more than 50%) of the terrestrial organic carbon appears near the Changjiang River Estuary, and their isolines project towards northeast, indicating the influence of Changjiang dilution water. The terrestrial particulate organic matter suffers from effects of diagenesis, benthos and incessant inputting of dead organic matter of plankton, after depositing in seabed. Therefore, the contribution of terrestrial organic carbon to particulate organic matter is obviously greater than that to organic matter in sediments in the same place.

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    Source of Major Anions and Cations of Snowpacks in the Typical Monsoonal Temper ate Glacial Region of China
    LI Zongxing, HE Yuanqing, PANG Hongxi, YANG Xiaomei,JIA Wenxiong, HE Xianzhong, WANG Xufeng, YUAN Lingling,NING Baoying, SONG Bo, ZHANG Ningning
    2007, 62 (9):  992-1001.  doi: 10.11821/xb200709010
    Abstract ( 433 )   PDF (2568KB) ( 487 )   Save

    Snowpacks samples were collected from two glaciers: Baishui No.1 Glacier and Hailuogou No.1 Glacier in June, 2006. The methods of sea-salt ions tracer, correlation analysis and trend analysis were used in this research in order to confirm the source of main ions, which indicated that Na+ is mainly from marine moisture and other ions mainly originate from land dust; the non-marine source percentages of Cl-、NO3 -、SO4 2- 、K+、Ca2+、Mg2+ are 52%, 99%, 100%, 98%, 99.9% and 83%, respectively, in Hailuogou No.1 Glacier, while the corresponding values in Baishui No.1 Glacier are 68%, 99%, 100%, 98%, 99% and 59%. The non-marine source of ions is from dust of central Asian arid regions carried by westerly circulation and the plateau borne-areas with the Qinghai-Tibet Plateau winter monsoon in two glacial areas. However, the import of local dust in glacial area has made a great contribution to ions concentration in Baishui No.1 Glacier, which accounts for the much higher ions concentration in Baishui No.1 Glacier than that of Hailuogou No.1 Glacier. It is obvious that the source of each ion is different between Hailuogou No.1 Glacier and Baishui No.1 Glacier. There are three reasons which can explain it: firstly, the difference of the internal environment of the glacial area, such as lithology, hollow wind system, topographical relief and so on; secondly, the influence exerted by ions eluviation in snowpacks section with ions eluviation in Hailuogou No.1 Glacier being very strong; and thirdly, the discrepancies caused due to varying ions transporting styles, deposition modes, chemical characteristics and post-ions-deposition process.

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    Hydrological Rule and Isotopic Composition of Water Bodies in Yar lung Zangbo River
    GAO Zhiyou, WANG Xiaodan, YIN Guan
    2007, 62 (9):  1002-1007.  doi: 10.11821/xb200709011
    Abstract ( 739 )   PDF (1812KB) ( 708 )   Save

    Based on data of runoff and water isotopic compositions in the Yarlung Zangbo River, this paper mainly analyzes the spatio-temporal distribution of runoff and isotopic effect of precipitation in this area. In the trunk-stream drainage area, the average annual runoff presents a trend of gradual decrease from lower reaches to upper reaches, and the intra-annual surface runoff mostly concentrates in summer and autumn (June to October). The isotopic compositons of most water samples fall on the top right of the global precipitation line, δD = 8 δ18O+10, showing that they have experienced intensive evaporation. With obvious region-continental effect and altitude effect, the distribution of water isotopic compositions is related to the movement of precipitation clouds from Bay of Bengal and Nujiang River and is affected by the topographic and climatic conditions of the Qinghai-Tibet Plateau.

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