共查询到20条相似文献，搜索用时 187 毫秒
1.
Shouye YANG 《中国地球化学学报》2006,25(B08):268-268
The Yangtze （Changjiang） River as the largest fiver originating from eastern Tibetan Plateau, has increasingly attracted considerable attention of many researchers for almost one hundred years. The fiver linking the Tibetan Plateau with the West Pacific Marginal Sea, encompasses variable source rocks and complicated drainage patterns and spans across distinct climate zones. The increasing human activities in the last 2000 years have significantly changed the weathering process and sediment source-to-sink pattern in the fiver basins. In terms of this, the Yangtze drainage basin as well as the deltaic and coastal areas can be regarded as one of the best regions in the world to investigate the source-to-sink process of continental sediments into the marginal sea. In the past ten years we systematically measured elemental and Sr-Nd-Pb isotopic compositions of the Yangtze riverine sediments which were collected from the mainstream and main tributaries. Analytical results clearly showed that the Yangtze sediments yield geochemical compositions different from those of other fiver sediments due to the very complicated source rock types and variable chemical weathering regimes in the large drainage basin. REE and Sr-Nd isotopic compositions suggest that the sediment source-to-sink pattern in the modern Yantze River basins varies considerably from the upper basin to the lower valley. Different chemical compositions among the main tributaries and the mainstream are responsible for the compositional variations of the Yangtze River sediments. It is a piece of quite challenging work to establish a sediment source-to-sink model to quantifying the contributions of the main tributaries to the mainstream. 相似文献
2.
Damming effect on the distribution of mercury in Wujiang River 总被引：2，自引：0，他引：2
Seasonal changes in total mercury concentrations in surface water were observed for the Wujiang River, with higher values at the time of greater flow. The total mercury in this river was mostly associated with suspended particles, particulate mercury accounting for 84% of the total mercury flux on average during the high flow period, and 52% of the total mercury flux on average in the low flow period. Significant losses of Hg from the water were observed in the downstreams of the reservoir. In addition, the concentrations of particulate mercury in the downstreams of reservoir appeared to have been enhanced by sediment re-suspension and shoreline erosion caused by flood discharge, while the filtered portion decreased. These observations suggested that reservoirs played an important role in controlling the transport and fate of mercury in the Wujiang River. 相似文献
3.
Dong WANG Yunliang SHI Lachun WANG Jichun WU 《中国地球化学学报》2006,25(B08):169-169
Water resources system is composed of natural water subsystem and social water subsystem. And it is a complicated large system, which contains certain regional background, as well as specific framework, function and dynamic balance. The evaluation of the water resources system needs the viewpoint of sustainable development and the measurement according to water resources system carrying capacity, which holds the meaning of both water resources carrying capacity and water environment carrying capacity. The Changjiang River Delta is a very important area in China. As the local water resources are concerned, the Delta is an area lack of water as a matter of fact. The water resources system of the Delta experiences a long, intricate and degenerate period. The lack of water due to resources shortage in the 1950＇s was converted to that due to water quality from the 1980＇s. Furthermore, the status of water shortage sharpens gradually. The representations are summarized as follows： firstly, the discharge amount of wastewater and polluted water is large all along. Secondly, the pollution status of rivers, which involve the Changjiang River, the Grand Canal, the rivers in cities and the rivers in small towns and villages, is noticeable. Thirdly, water quality of Taihu Lake is worth of more attention. Therefore, the countermeasures on the reconditioning and regulating of water resources system in the Delta demands the following new strategies, such as to treat the rivers, the lakes and the seas as one overall system, to improve, harmonize and counterpoise water resources system carrying capacity, to implement the integrated management of water resources, which means the integrated management of drainage area along with the regional area, especially the integrated management of city water, and to carry on water saving and scientific use so as to increase the efficiency of water use, and so on. 相似文献
4.
《中国地球化学学报》2006,(Z1)
The impact of water quality changes of the Changjiang River on dissolved CO2 and silicate concentration and seasonal flux in the water column for the past decades were evaluated, based on monitoring data from hydrographic gauge. It was found that dissolve… 相似文献
5.
Zhigang YAO Zhengyu BAO Pu GAO 《中国地球化学学报》2006,25(B08):137-137
Although eutrophication and trace element contamination are two key environmental problems in Dongting Lake, a systematic study of the distribution of trace elements in sediments of this lake has not previously been undertaken. In order to identify the current levels of trace metal contamination in Dongting Lake, the concentrations of trace elements （Cd, Cr Cu, Ni, Pb, Zn, As and Hg） in the sediments at 53 locations were investigated in this study. The lake, the second largest fresh-water lake in China, boasts three China wetlands of international importance. Dongting Lake which lies in the south of the middle Yangtze River is the most important reservoir lake in the Yangtze River drainage area, and is characterized by fast flow-through water, large runoff volume and short period of exchanging water （no more than 20 days）. The granulometric analysis result of sediments shows that a large proportion of the sediments measures at 2-63 μm in size; the result of mineralogical analysis shows that original mineral is the main composition of the sediments, followed by clay mineral and carbonate. The contents of copper, lead, zinc, cadmium, arsenic and mercury are higher than the background levels of soil （ Ⅰ Soil） in China, but lower than the threshold values for severely polluted soil （Ⅲ Soil） in China except Cd higher than that in Ⅲ Soil. The concentrations of trace elements analyzed are higher than the Threshold Effect Level of Interim Sediment Quality Guideline by Canada EPA and are lower than the Probable Effect Level. The assessment by geoaccumulation index shows that the contamination of Cd reached strong level in Dongting Lake. Study on speciation of metals by a BCR procedure indicates that the trace elements （Cu, Zn, Cr, and Ni） analyzed are mainly distributed in residual phases but Pb in Fe/Mn oxhydroxide phase and Cd in soluble and carbonate-bound fraction. The potential risk was the highest in East Dongting Lake based on the calculated contamination factors which are mostly probably caused by the deposition of the trace element pollutants via the Xiangjiang River and the discharge of the pollution sources in the vicinity of East Dongting Lake. 相似文献
6.
Chuxia LIN Yonggui WU Wenzhou LU Aisheng CHEN Yong LIU 《中国地球化学学报》2006,25(B08):39-40
Field and laboratory work was carded out to investigate the chemistry and ecotoxicity of stream water affected by acid mine drainage in a tributary catchment of the Pearl River in subtropical China during a major flood event that corresponded to a return period of 100 years occurred in the study area. The results indicate that stream water was affected by acid mine drainage from the Dabaoshan Mine at least to a distance of 25 km downstream of the mine water discharge point. It appears that sulfide-H^＋ from the waste rock dumps was readily available for discharging and the amount of H^＋ being transported outwards depended on the volume of out-flowing waters. However, there was a lag time for the discharge of the metals. This may be attributed to the slower release of metals, relative to H^＋, because it might take more time for the dissolution of heavy metal-bearing compounds. Fe, Zn and Al were the major metals of potential toxicity contained in the AMD-affected stream water, followed by Mn, Cu, Pb, As, Cd and Ni. Acute toxicity tests show that the AMD-affected stream water at 3.5 km downstream of the discharge point was highly toxic to the test organisms. 相似文献
7.
Yuchun WANG Jun ZHU Congqiang LIU 《中国地球化学学报》2006,25(B08):161-162
Damming is a common anthropogenic intervention along the course of rivers, which is defined as ＂artificial-lake effect＂, both in China and across the world. Today as many as 48000 dams and/or reservoirs are in operation in the Changjiang River （Yangtze River） drainage area, and more are being constructed. While damming is well known to affect riverbome nutrient loads, and thus the riverine ecosystems owing to removal of carbon fixation, and removal of particles in reservoir sediments, there is limited information on the detailed early diagenesis of sediments in reservoirs including the regeneration processes of nutrients deposited in sediments and exchange flux across the sediment-water interface, which is important for mass balance of riverbome nutrients. In the present study, two large-size reservoirs, Wujiangdu Reservoir （WJDR） and Dongfeng Reservoir （DFR）, located on the main steam of the Wujiang River and with uniformity hydrography and discrepancy biogeochemical activity （e. g. primary production）, were selected for a comparative study on the detailed processes of nutrient regeneration. Water, pore water and sediment were sampled from these two reservoirs and dissolved organic carbon （DOC）, NH4^＋, NO3^-, PO4^3-, dissolved silica （DSi） in the overlying water and pore water, and total organic matter in sediments were determined. The results of correlation analysis suggested that in these two reservoirs, processes of nutrient regeneration near the sediment-water interface were significantly different. As a result of rapid decomposition of algae-derived ＂labile＂ organic matter in upper sediments, nutrient regeneration processes and upward fluxes in WJDR are dramatically stronger than those of DFR. NH4^＋ upward flux from sediment in WJDR was about 17 times higher than that in DFR. PO4^3- flux in WJDR is about 13 times above that in DFR. DOC flux in WJDR is larger that in DFR by 5 times, and DSi by 1 time. 相似文献
8.
Xuyin YUAN Zhiyong SHEN Xu DENG Yun GAO 《中国地球化学学报》2006,25(B08):140-141
Several rivers researched around Taihu Lake in Chinese eastern plain are distributed to the west of the lake. Pollutants of different types from tributaries and inlets flow directly into the main rivers and finally into the lake. They change trace elements of rivers fi＇om which we can analyze. Researches about trace elements are helpful for understanding the pollutant characteristics, industrial structure and agricultural cultivation in the area of network rivers in the plain of China. Samples of water column, suspended matter and sediment were collected fi＇om the west rivers of Taihu Lake, which represent three typical rivers. Observation in the field and the primary composition analysis showed the Caoqiao River was mainly contaminated by industrial wastewater, the Liangxi River was discharged by domestic sewage and the Dapu River was principally input by farmland runoff. REE concentrations and their normalized curves showed obvious characters for rivers discharged by different sewages. The contents of total REE in water column followed the order of the Caoqiao River, the Dapu River and the Liangxi River fi＇om high to low. TREEs in suspended matter and sediments follow the order of the Dapu River 〉 the Caoqiao River 〉 the Liangxi River. REE normalized curves （for Australia shale） suggested that significant diversities were presented in water column, suspended matter and sediments, i.e., heavy REE enrichment in water, middle REE enrichment in suspended matter, and smooth curves for sediments. But the heavy pollution resulted in several anomalous curves in the same rivers. Some element ratios were selected as indices for polluted rivers based on their geochemical properties and diversities between rivers. The results displayed the discriminative indices for water column, suspended matter and sediment. The effective indices were Pb/Fe, Cr/Fe, Ni/Fe, Pb/Ni, Zn/Ni for water column, Cu/Al, Cu/Fe, Zn/Fe, K/Ca, K/Na, Pb/Co, Zn/Co for suspend matter and Pb/Fe, K/Ca, Ca/Mg, Zn/Ni for sediment, respectively. In general, rivers mainly discharged by industrial sewage have high ratios of Pb/Ni, K/Ca, are enriched in the middle REE and have positive Gd anomaly. The domestic sewage flowing into rivers reveals high ratios of Zn/Ni, Pb/Fe, and is enriched in the heavy REE, and has the positive Eu anomaly. If runoff of farmland enters into the rivers, it will have high ratios of Ca/Mg, K/Na, high lanthanum, and show the smooth normalized curves of REE. 相似文献
9.
ZHANG Chun-chao LI Xiang-quan GAO Ming HOU Xin-wei LIU Ling-xia WANG Zhen-xing MA Jian-fei 《地下水科学与工程》2017,5(3):222-234
In Yuqia Basin, the climate is arid and the ecologic environment is fragile, and shortage of water resources has seriously restricted the sustainable development of local economy. In order to meet the needs of industrial and domestic water in the Yuqia Basin, numerical simulation was used to evaluate the groundwater resources and potential for exploitation. The results showed that the mathematical model and calculation parameters used were mainly in accordance with practical situation. The calculated value of the underground water level is consistent with measured value during the period of identification and validation. The total recharge of groundwater resources was 22.02×10~4 m~3/d, and the total drainage was 21.95×10~4 m~3/d at present. The Yuqia River leakage is the main supply source of groundwater. There is no significant effect on area of wetland when water source place exploited by 2.5×10~4 m~3/d at alluvial-diluvial fan of Yuqia River. After long-term exploitation, the spring flow reduces from 1.42×10~4 m~3/d to 1.01×10~4 m~3/d and wetland area reduces by 32.7% of original area. The calculation of water balance shows that it is safe to the Yuqia Basin, Da Qiadam Lake, the Mahai Basin at downstream of Yuqia River and wetland under the condition of water source place exploited by 2.5×10~4 m~3/d. 相似文献
10.
River runoff is an important water resource in the arid region of northwest China. Under the back⁃ ground of climate change,the exploration on change characteristics and influencing factors of river runoff is of great significance for understanding the law of river hydrological change. Based on the daily discharge of Chang⁃ mabao hydrological station,the observation materials from meteorological stations and radiosonde stations,and the first and second Chinese glacier inventory,the variation characteristics and possible influencing factors of runoff in the upper Shule River were systematically analyzed by using the linear trend,empirical mode decompo⁃ sition and hierarchical multiple regression. The results show that the annual runoff of the upper Shule River showed a significant increasing trend during 1954-2016,with a rate of 1. 00×108 m3·（10a）-1. Both runoff in flood period and non-flood period also showed a similar increasing trend. The runoff suddenly changed in 1999 and had two oscillation periods of about 15a and 7a,among them the 15a oscillation period was the most signifi⁃ cant. Both cumulative positive temperature and precipitation were the main climatic factors affecting the runoff in the upper Shule River,which can explain more than 80% of the runoff change. There was a significant posi⁃ tive correlation between the summer runoff in the upper Shule River and the height of 0 ℃ layer. It means that the height changes of 0 ℃ layer can be used to predict the runoff change of the river in flood period,which provides an important reference for evaluating the runoff change of glacial melt recharge rivers in the arid re⁃ gion of northwest China. From 1966 to 2006,the ice volume in the upper Shule River basin decreased by about 5. 77 km3,indicating that glacier changes play a crucial role in the change and regulation of runoff in the basin. © Journal of Glaciology and Geocryology 2022. 相似文献
11.
Human impact on the historical change of CO<Subscript>2</Subscript>degassing flux in River Changjiang 总被引：2，自引：0，他引：2
The impact of water quality changes in River Changjiang (formally known as the Yangtze River) on dissolved CO2 and silicate concentrations and seasonal carbon flux in the past several decades (1960s–2000) was evaluated, based on monitoring
data from hydrographic gauge. It was found that dissolved CO2 and silicate in Changjiang decreased dramatically during this decades, as opposed to a marked increase in nutrient (e.g. NO3
-) concentrations. Our analyses revealed that dissolved CO2 in Changjiang was over-saturated with the atmosphere CO2, and its concentration had showed a declining trend since the 1960s, despite that fluvial DIC flux had maintained stable.
Analysis results also suggested that the decrease in dissolved CO2 concentration was attributed to changes on the riverine trophic level and river damming activities in the Changjiang drainage
basin. Due to the economic innovation (e.g. agriculture and industry development) across the Changjiang watershed, fertilizers application and river regulations have
significantly altered the original state of the river. Its ecosystem and hydrological condition have been evolving toward
the "lacustrine/reservoir" autotrophic type prevailing with plankton. Accordingly, average CO2 diffusing flux to the atmosphere from the river had been reduced by three-fourth from the 1960s to 1990s, with the flux value
being down to 14.2 mol.m-2.yr-1 in the 1990s. For a rough estimate, approximately 15.3 Mt of carbon was degassed annually into the atmosphere from the entire
Changjiang drainage basin in the 1990s. 相似文献
12.
Estimating non-point source pollutant loads for the large-scale basin of the Yangtze River in China 总被引：1，自引：0，他引：1
Xiao Wang Fanghua Hao Hongguang Cheng Shengtian Yang Xuan Zhang Qingsong Bu 《Environmental Earth Sciences》2011,63(5):1079-1092
Taking advantage of the opportunity provided by the nationally funded Water Resources Integrated Planning and Investigation
of China program (WRIPI), a model was established to estimate non-point source pollutant loads in a large-scale basin (ENPS-LSB)
on the basis of hydrological processes and pollutant transport. The model made use of Environment for Visualizing Images software
(ENVI) and Interactive Data Language (IDL) and took the characteristics of present-day China into account: a huge rural population
scattered widely, marginal rural infrastructure and livestock cultivation based on scatter-feeding. The model was divided
into two sections: one on dissolved and one on adsorbed pollutant loads. The dissolved loads were divided into four different
types: those originating from agricultural fields, urban areas, rural residential areas, and livestock. The study was undertaken
in the Yangtze River Basin. The results showed the chemical oxygen demand (COD), the total nitrogen (TN), the total phosphorous
(TP), and the ammonia nitrogen (NH3–N) loads to be 2.6 × 106, 1.6 × 106, 9.3 × 105 and 3.1 × 105 tons, respectively, in the year 2000. The dissolved COD resulted mainly from rural residential areas and livestock; 76.8%
of the dissolved TN and 86.4% of the dissolved TP produced were from agricultural fields. The Yangtze River Delta, the lower
reaches of the Han River, and part of the Dongting Lake, Taihu Lake and Poyang Lake basins all had relatively high dissolved
pollutant loads; adsorbed nitrogen and phosphorus loads were mainly observed in the middle and upper reaches of the Yangtze
River Basin. Dissolved loads were most affected by human activity, whereas adsorbed loads were most affected by natural factors.
The results showed that the model performed well on large scale, describing pollutant loads effectively. This makes it possible
to properly consider not only point source pollutant discharge but also non-point source pollution in the Yangtze River Basin.
Combining point source discharge investigation with the ENPS-LSB model could assist environmental management with controlling
water pollution. 相似文献
13.
西江流域的有机碳侵蚀通量 总被引：12，自引：1，他引：11
在西江下游的马口水文站对径流进行了4个季节的有机碳采样分析。研究表明,西江径流有机碳的断面构成在各个季节均较为一致;季节性变化表现为,有机碳和悬浮物含量随流量的增加而增加。随着水体悬浮物含量的增加,悬浮物的有机碳含量呈对数趋势降低。西江流域的有机碳侵蚀通量为10.18×106gC/km2·yr.,是全球外流域有机碳侵蚀通量的2～3倍,其中以颗粒有机碳的侵蚀通量为主,达到8.30×106gC/km2·yr.,溶解有机碳的侵蚀通量为1.88×106gC/km2·yr.。反映了流域内较强的机械剥蚀过程,这与西江流域典型的季风气候、较大的地形高差,以及农业耕作历史长久、土地利用强度较大等因素有关。 相似文献
14.
利用1979-2016年金沙江支流漾弓江流域木家桥水文站流量资料和丽江市气象资料,揭示了漾弓江流域径流变化特征及其主要影响因素。研究结果表明：漾弓江流域年径流量呈先增加后减小趋势。在年代际时间尺度, 20世纪80年代、90年代以及2000-2009年,径流量呈现增加趋势,而2010-2016年径流量呈减小趋势,与2000-2009年相比, 2010-2016年径流量减少了42%（减少径流量为0.88×108 m3）。气温和降水量对径流的影响均较为显著,其中,降水量对径流的影响主要体现在雨季,而气温对径流的影响主要体现在消融期。气温升高导致冰川累积负物质平衡,进而引起冰雪融水变化,漾弓江流域2000-2009年径流变化的主要原因。 相似文献
15.
基于在研究前人洞庭湖冲积平原区土壤测量资料时发现湘江、资水、沅江、澧水河口三角洲土壤中有明显的成矿元素聚集,且成矿元素的种类、含量与流域内的矿产种类、储量大小密切相关等的资料,以及6年来已经在湘江流域发现了一处巨型锡矿,铜、金矿勘查取得了重大进展的成果,对湘江、资水、沅江、澧水的三角洲及洞庭湖平原长江沉积物中的元素含量做进一步的预测研究。研究结果表明:1)用河口三角洲沉积物中的元素含量减去背景值后的值与汇水盆地面积、厚度及岩石密度相乘的乘积可以大致预测数万平方公里流域内的矿产储量;2)将沉积物厚度分别规定为1.5m,2m,3m和5m,可大致体现不同地质工作程度所取得的储量;3)6年来锡储量的增加完全证实了预测的一定可靠性;4)利用湘江、资水、沅江、澧水河口三角洲元素含量预测上游流域内矿产储量的可行性,大胆探索了利用洞庭湖沉积物中成矿元素含量预测长江上游100余万平方公里汇水流域内的矿产储量。2004年谢学锦院士与挪威的J.Bogen和R.Ottesen开始酝酿一个全球大科学计划“沿世界主要河流的全球地球化学填图”。计划在世界主要大江大河及其支流的河口共采集2000～2500个组合样,分析其中71～76种元素及一些有机物的含量,用以迅速评估全球矿产资源潜力与环境现状。文章认为, 相似文献
16.
Water discharge from the Patuxent River into its estuary was near-average (95%) during the water year 1968–1969 although precipitation was only 79% of the average. Suspended-sediment discharge into the estuary, however, was more then double the normal yield (344 metric tons/km2 compared to 143 metric tons/km2). These increases in runoff and suspended-sediment yields, despite decreased precipitation, must be attributed to urbanization of the drainage basin.The maximum measured suspended-sediment concentrations in the rural Middle Patuxent basin (Piedmont Province) increased only 40-fold during an increase from “average” to high water runoff (15 mg/l to 600 mg/l). In the portion of the Little Patuxent River basin undergoing urbanization (Piedmont portion), stream concentrations increased by over two orders of magnitude (20 mg/l to 2400 mg/l) as a result of heavy rainfall. The area undergoing urbanization of the Little Patuxent yielded more than twice as much suspended sediment per unit area as the rural Middle Patuxent (620 metric tons/km2 versus 290 metric tons/km2). This increase also is interpreted to be the direct result of erosion of soils denuded or disturbed during urban construction.Using the Middle Patuxent as a “standard” for normal erosion rates in rural areas, construction sites contributed about 82% of the suspended sediment discharged by the Patuxent River into its estuary even though such sites represented only 23% of the drainage basin. 相似文献
17.
近百年来东平湖沉积通量变化与环境 总被引：5，自引：0，他引：5
根据210Pb、137Cs法建立的东平湖现代沉积年代序列,结合沉积物粒度与烧失量变化特征以及黄河变迁与流域人类活动的特点,分析探讨了1889年以来东平湖沉积通量的变化。研究表明,百年来东平湖沉积环境不稳定,沉积通量变化较大:1889~1938年,沉积通量较高且基本稳定,1938~1965年,沉积通量逐年下降,1965~2000年,沉积通量整体较低且基本稳定,2000年以来,沉积通量呈逐年上升趋势。早期的高沉积通量与东平湖作为黄河自然滞蓄洪区有关,后期由于人类活动（湖区治理、黄河水利工程建设等）控制了黄河水的自然倒灌,导致了沉积通量的下降并趋于稳定,近期沉积通量的上升是湖区经济活动增强的反映。 相似文献
18.
岷江水流量约为8.9×1010m3/yr,约占长江全流域水量10%。作者对4个监测站监测数据的分析发现,岷江TZ 高于世界河流平均值,具有富HCO3-、Ca2 特征;流域化学剥蚀通量为20.48×106t/yr,约占长江流域的10%;化学剥蚀速率为155.9t/km2.yr。岷江在流经四川盆地时主要离子SO42-、Cl-和Ca2 均已受到了人类活动较为严重的影响,酸雨是SO42-的主要污染来源,Cl的污染来源包括生活和工业废水、化肥和井盐开采,农业生产使用的富Ca化肥应是河流Ca污染源之一。 相似文献
19.
新疆开都-孔雀河流域绿洲需水量与稳定性分析 总被引：3，自引：0，他引：3
水是绿洲存在和发展的核心, 干旱区绿洲稳定性与水密切相关. 根据2000-2009年资料, 采用蒸发系数法和定额法估算开都-孔雀河流域绿洲自然生态系统和社会经济系统综合需水量, 并对水资源约束条件下的绿洲稳定性进行初步探讨. 结果表明: 2000-2009年, 绿洲年均总需水量理论值约为54.80×108 m3, 其中开都河绿洲总需水量约为20.55×108 m3, 孔雀河绿洲总需水量约为21.90×108 m3, 博斯腾湖区耗水量约为12.35×108 m3, 与绿洲10 a平均供水量相比, 供需表现出极大地不平衡性. 水资源可承载绿洲面积(不含博斯腾湖)约为3139.66 km2, 其中可承载灌溉地面积约为1395.41 km2, 与绿洲10 a平均面积5 248 km2相比, 差别较大, 绿洲处于不稳定状态, 现状绿洲面积应适当收缩. 最后, 对博斯腾湖最低生态水位进行讨论, 初步把大湖最低水位定为海拔1 045 m, 小湖最低生态水位定为海拔1 046.5 m. 相似文献