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1.
生态补水是维持和改善白洋淀生态环境的重要途径.为研究生态补水对白洋淀水环境的影响,分别在补水前与补水后采集淀水、河水及地下水样品,分析区域地表水和地下水水化学特征.结果表明：（1）白洋淀补水前、后地表水与地下水的水化学组成中Na+为主要阳离子,补水后阴离子以HCO3-为主,淀区南部地表水电导率高;补水后地表水与地下水Ca2+、Mg2+和HCO3-浓度显著增加,水体电导率降低.（2）补水前地下水为Na-HCO3型水,地表水主要为Na-Cl·SO4及Na-Cl·HCO3类型;补水后地表水与浅层地下水向Ca·Mg-HCO3型演化,深层地下水水化学类型基本保持不变.（3）生态补水使白洋淀水位升高,淀区水面积增大,缓解了水资源短缺的问题;同时也使浅层地下水水化学组成发生改变,而深层地下水暂未受到影响.生态补水后,受稀释和混合作用的影响,水体Na+、Cl-和SO42-浓度显著下降,Ca2+、Mg2+及HCO3-浓度增加.在白洋淀生态补水中应"先治污,后补水",以减少补水过程中污染物向淀区的运移,还应注意区域地下水位上升过程中的阳离子交换及水岩相互作用,为合理调配生态补水及改善白洋淀生态环境提供科学依据. 相似文献
2.
本文通过揭示宵蔵盐湖卤水在浓缩过程中成盐元素的行为以及卤水水化学炎型与PH值等的变化，得出结论如下：1.卤水中主要离子的演化方向是按Ca2+→Na+→K+→Mg2+→Ca2+（阳离子）和CO32-→HCO3-→SO42-→Cl-（阴离子）顺序进行。2.除了析出固体外，微量元素一般在最后的浓缩卤水和析盐后的残余卤水中髙度富集。已査明盐湖卤水中有63种元素，其中钾、镁、硼、锂、铷、铯、铀、钍、稀土、氘已构成可以综合利用的宝贵资源。 相似文献
3.
对柴达木盆地察尔汗盐湖区外围沙下盐湖的卤水及沉积进行了综合研究。沙下盐湖卤水化学组成与地表径流和开放性盐湖卤水之间存在明显的差异性,具有高Na++Cl-、低Mg2++Ca2++SO42-、贫K++CO32-+HCO3-等特征。沙下盐湖析盐层位含有新生矿物并夹带碎屑矿物,其盐类矿物组合为:石盐+羟氯镁铝石+光卤石。25℃等温蒸发相图表明,其卤水演化方向往光卤石析出区迁移,在穿越上覆盖层通道中卤水发生的物理化学反应与独特的沉积特征,可以作为继续寻找沙下盐湖的指导。 相似文献
4.
通过模拟沙湖沉积物-水系统,以沙湖原水氟离子（F-）浓度为1倍浓度（0.69 mg/L）,设置0.5倍浓度、1倍浓度、1倍浓度灭菌、2倍浓度和4倍浓度共5个实验组,探究不同上覆水F-浓度背景下沙湖沉积物中F-的迁移.结果表明,沉积物F-的释放量随上覆水F-浓度的增加而呈下降的趋势,其中2倍和4倍浓度组的沉积物由释放F-转变为吸附F-.碱性水体有利于沉积物F-的释放,即随着pH增大,F-释放量也会增加.微生物的Beta多样性层次聚类分析表明,F-会抑制Paenisporosarcina与Thiobacillus的相对丰度,但对Fusibacter的生命活动具有促进作用.根据各浓度组间优势菌属相对丰度与环境因子的冗余分析可得,Acinetobacter、Thiobacillus相对丰度与pH呈负相关;Fusibacter相对丰度与F-浓度呈显著正相关,而Thiobacillus的相对丰度则与F-表现出弱负相关.通过对各浓度组中重要离子的分析发现,0.5倍组和4倍组中F-的迁移受Ca2+、HCO3-和SO42-浓度影响较大;相关性分析表明0.5倍浓度组的Ca2+、HCO3-浓度与F-浓度呈极显著正相关,而4倍组中F-浓度和Ca2+、HCO3-浓度呈负相关,SO42-浓度和F-浓度的相关性则是0.5倍组呈负相关,4倍组呈极显著正相关.本文在不同上覆水F-浓度背景下全面探究了沙湖沉积物中F-释放和迁移机理,为沙湖及其他含氟地表水的氟污染防治提供理论支持. 相似文献
5.
南极洲万达盐湖为饱和方解石湖水。计算出的方解石饱和指数随水深增加而变化。在Ca~(2+)及HCO_3~-活度值均一的上部氧化环境湖水中,pH及溶解氧(DO)是控制该变化的主要因素,在下部还原环境湖水中,Ca~(2+)及HCO_3~-的活度对方解石的饱和指数SI的变化起主要作用。这充分揭示了湖底部近代沉积物中分布较多方解石矿物的原因。 相似文献
6.
为揭示太湖流域降雨和湖水酸根阴离子长期变化特征及环境意义，通过历史数据收集和采样分析，对太湖流域降雨和湖水中的SO42-、NO3-变化特征和来源进行了研究.结果表明：自1990s以来太湖流域降雨中SO42-呈显著下降趋势，年平均下降率为0.28 mg/（L·a）；NO3-浓度却呈显著上升趋势，年平均增长率为0.05 mg/（L·a），降雨中氮污染呈现加重的趋势.与之相反，湖水中SO42-呈显著上升趋势，年平均增长率为1.24 mg/（L·a）；NO3-浓度却呈显著下降趋势，年平均下降率为0.02 mg/（L·a）.30年以来，太湖水体SO42-/NO3-比值不断升高，远高于降水SO42-/NO3-比值.研究认为：流域SO2排放引起的酸沉降是湖水SO42-浓度增长的最重要原因，但氮氧化物排放并未引起湖水NO3-浓度升高，说明太湖流域对大气沉降的氮氧化物有滞留作用，而太湖水体是流域大气沉降硫酸盐的重要汇.综合治理太湖流域酸性物质排放对防止太湖水体酸化和治理富营养化都具有重要意义. 相似文献
7.
为探究筑坝后不同水库物理、化学、生物过程对水化学和碳循环的影响,本研究对贵州三岔河流域的平寨水库、普定水库以及猫跳河流域的红枫湖水库进行研究,于2018年3月2019年1月分别在入库河流和库区采集了分层水样和沉降颗粒物,并探究水中主要离子及颗粒物通量的时空变化特征及其控制因素.结果表明,水体主要离子的主要来源受碳酸盐溶解影响,并且离子浓度受光合作用控制.红枫湖水库水体水化学类型为Ca-Mg-HCO3-SO4型,普定水库、平寨水库水化学类型均为Ca-HCO3-SO4.夏季藻类光合作用诱导碳酸盐沉淀导致水体表层Ca2+、HCO3-及溶解态Si浓度降低,其降低幅度分别为20.87%~44.25%、33.12%~51.18%、48.55%~96.34%.此外,藻类光合作用也影响C、N、Si等生源要素间的化学计量关系.Mg2+/Ca2+比值在水体垂向剖面上主要受碳酸钙沉淀的控制,而在不同水库之间则主要受流域岩性的控制.根据沉积物捕获器通量计算的平寨水库、普定水库、红枫湖水库夏季颗粒无机碳沉积通量分别为0.74、1.36、0.27 t/（km2·d）,而根据水体Ca2+浓度降低计算的通量分别为0.31~0.64、0.35~0.99、0.09~0.29 t/（km2·d）,根据水体HCO3-浓度降低计算的通量分别为0.30~0.65、0.29~1.26、0.12~0.33 t/（km2·d）.其红枫湖水库无机碳沉降通量的实测值与计算值接近,而平寨、普定水库实际沉降通量高于计算值,这可能是有外源输入导致.因此,利用水化学分层数据能对喀斯特水库中的无机碳沉降通量进行合理估算,并且能够得到较好的估算结果,从而指示碳循环的过程. 相似文献
8.
通过测量辽宁省鞍山-海城地区地震重点监测区地下水离子浓度和氢、氧同位素组成，讨论了该区地下水化学类型的时空变化及其成因。测量结果表明，取样点水温变化范围为11.0～97.0℃，水样的总固溶物（TDS）在197.89～829.99mg/L之间，水样分为8种化学类型。大部分水样的δD、δ18O值均沿中国东北地区大气降水线分布，少数有所偏离，表明该区的地下水主要接受大气降水的补给，并可能有深部水的供给。研究区Ca-HCO3和Ca·Mg-HCO3型水主要是岩石风化溶解和阳离子交换作用的结果；Ca-HCO3·Cl和Ca·Na-Cl·SO4型水主要受岩石风化溶解、阳离子交换作用、深部卤水混入或人类活动影响；Ca-HCO3·SO4和Ca-SO4·HCO3型水与岩石风化溶解以及深部流体混入有关；Na-SO4·HCO3和Na-HCO3·SO4型水主要是深部来源水体的混入造成的。采样期间研究区发生2次ML≥3.0地震，采样点在地震发生月份出现了明显的离子浓度异常变化；Na+、Mg2+、Ca2+、Cl-和SO42-浓度变化明显，对地震活动响应较灵敏。 相似文献
9.
粤东五华河流域的化学风化与CO2吸收 总被引：1，自引：1，他引：0
基于对粤东五华河干流和支流水体的物理、化学组成测试数据,应用质量平衡法和相关分析法探讨湿热山地丘陵地区岩石化学风化过程对大气CO2的吸收.结果表明:五华河水体的总溶解性固体含量(77.11 mg/L)接近于世界河流的平均值(65 mg/L);离子组成以Ca2+、Na+和HCO3-为主,可溶性Si次之.五华河流域化学径流组成主要源自硅酸盐矿物化学风化过程的贡献,碳酸盐矿物的贡献较少;大气和土壤CO2是流域内岩石化学风化的主要侵蚀介质.与同一气候带其他河流相比较,五华河流域岩石化学风化过程对大气CO2的吸收通量(2.14×105mol/(km2·a))较低,这主要是由于流域内缺乏碳酸盐岩所导致. 相似文献
10.
旅游酒店排污影响下的岩溶地下水水化学变化 总被引：2，自引：1，他引：1
岩溶地下水系统具有高度的开放性和脆弱性，使得地下水极易遭受污染.为探究旅游酒店排污对岩溶地下水水化学变化的影响，以金佛山世界自然遗产地水房泉流域为例，对水房泉地下水的水化学进行自动化监测，对流域内雨水、土壤水、某酒店自来水、污废水进行定期采集，结合流域硝酸盐氮氧同位素分析.结果表明，监测期间水房泉水化学变化随酒店入住游客量总体表现为3个阶段：前期受降雨影响显著，旅游高峰期间水质急剧恶化，后期水质明显好转.酒店生活污废水的排放成为水房泉水化学演变的重要因素，硝酸盐氮氧同位素表明水房泉的NO3-主要来自粪便、污废水以及土壤N的混合.H2SO4及污水中HCl、有机酸等可能参与了碳酸盐岩的溶蚀，使水房泉Ca2+、Mg2+、HCO3-浓度增加明显.流域岩溶管道发育，地下水流速快，使污染物质扩散迅速，故在研究期间水房泉主要离子的浓度高峰对污废水排放高峰的响应仅滞后约4 d. 相似文献
11.
This study is undertaken to understand how calcite precipitation and dissolution contributes to depth-related changes in porosity and permeability of gas-bearing sandstone reservoirs in the Kela 2 gas field of the Tarim Basin, Northwestern China. Sandstone samples and pore water samples are col-lected from well KL201 in the Tarim Basin. Vertical profiles of porosity, permeability, pore water chem-istry, and the relative volume abundance of calcite/dolomite are constructed from 3600 to 4000 m below the ground surface within major oil and gas reservoir rocks. Porosity and permeability values are in-versely correlated with the calcite abundance, indicating that calcite dissolution and precipitation may be controlling porosity and permeability of the reservoir rocks. Pore water chemistry exhibits a sys-tematic variation from the Na2SO4 type at the shallow depth (3600-3630 m), to the NaHCO3 type at the intermediate depth (3630―3695 m),and to the CaCl2 type at the greater depth (3728―3938 m). The geochemical factors that control the calcite solubility include pH, temperature, pressure, Ca2 concen-tration, the total inorganic carbon concentration (ΣCO2), and the type of pore water. Thermodynamic phase equilibrium and mass conservation laws are applied to calculate the calcite saturation state as a function of a few key parameters. The model calculation illustrates that the calcite solubility is strongly dependent on the chemical composition of pore water, mainly the concentration difference between the total dissolved inorganic carbon and dissolved calcium concentration (i.e., [ΣCO2] -[Ca2 ]). In the Na2SO4 water at the shallow depth, this index is close to 0, pore water is near the calcite solubility. Calcite does not dissolve or precipitate in significant quantities. In the NaHCO3 water at the intermedi-ate depth, this index is greater than 0, and pore water is supersaturated with respect to calcite. Massive calcite precipitation was observed at this depth interval and this intensive cementation is responsible for decreased porosity and permeability. In the CaCl2 water at the greater depth, pore water is un-der-saturated with respect to calcite, resulting in dissolution of calcite cements, as consistent with microscopic dissolution features of the samples from this depth interval. Calcite dissolution results in formation of high secondary porosity and permeability, and is responsible for the superior quality of the reservoir rocks at this depth interval. These results illustrate the importance of pore water chemis-try in controlling carbonate precipitation/dissolution, which in turn controls porosity and permeability of oil and gas reservoir rocks in major sedimentary basins. 相似文献
12.
艾比湖水化学演化的初步研究 总被引：10，自引：0，他引：10
本文通过野外地质调查和大量样品的分析测试结果,从以下三个方面对艾比湖湖水的水化学特征进行论述:(1)湖水的矿化度和pH;(2)湖水的化学组成;(3)湖水化学组分的侧向分布。初步揭示了湖水水化学变化和主要化学元素迁移和富集的规律。艾比湖沉积物中碳酸盐矿物组成及其地球化学性质反映湖水化学组成的变动。这种变动明显受气候环境变化的影响。因此,CK4孔和湖底沉积物中的碳酸盐沉积,提供了许多信息作为湖水化学演化和古气候波动的标志,根据其碳酸盐含量、方解石含量、方解石格架中MgCO_3mol.％、Sr含量和Sr×1000/Ca比值,最后结合碳酸盐的沉积特征、地球化学演化和古沙嘴的演变,进一步阐明了湖水化学演化的趋势。 相似文献
13.
Corinne Tarits Robin W. Renaut Jean‐Jacques Tiercelin Alain Le Hriss Jo Cotten Jean‐Yves Cabon 《水文研究》2006,20(9):2027-2055
Lake Baringo, a freshwater lake in the central Kenya Rift Valley, is fed by perennial and ephemeral rivers, direct rainfall, and hot springs on Ol Kokwe Island near the centre of the lake. The lake has no surface outlet, but despite high evaporation rates it maintains dilute waters by subsurface seepage through permeable sediments and faulted lavas. New geochemical analyses (major ions, trace elements) of the river, lake, and hot spring waters and the suspended sediments have been made to determine the main controls of lake water quality. The results show that evaporative concentration and the binary mixing between two end members (rivers and thermal waters) can explain the hydrochemistry of the lake waters. Two zones are recognized from water composition. The southern part of the lake near sites of perennial river inflow is weakly influenced by evaporation, has low total dissolved species (TDS), and has a seasonally variable load of mainly detrital suspended sediments. In contrast, waters of the northern part of the lake show evidence for strong evaporation (TDS of up to eight times inflow). Authigenic clay minerals and calcite may be precipitating from those more concentrated fluids. The subaerial hot‐spring waters have a distinctive chemistry and are enriched in some elements that are also present in the lake water. Comparison of the chemical composition of the inflowing surface waters and lake water shows (1) an enrichment of some species (HCO3?, Cl, SO42?, F, Na, B, V, Cr, As, Mo, Ba and U) in the lake, (2) a depletion in SiO2 in the lake, and (3) a possible hydrothermal origin for most F. The rare earth element distribution and the F/Cl and Na/Cl ratios give valuable information on the rate of mixing of the river and hydrothermal fluids in the lake water. Calculations imply that thermal fluids may be seeping upward locally into the lake through grid‐faulted lavas, particularly south of Ol Kokwe Island. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
14.
Characteristics of δ13CDIC in lakes on the Tibetan Plateau and its implications for the carbon cycle
Dissolved inorganic carbon isotope (δ13CDIC) is an important tool to reveal the carbon cycle in lake systems. However, there are only few studies focusing on the spatial variation of δ13CDIC of closed lakes. Here we analyze the characteristics of δ13CDIC of 24 sampled lakes (mainly closed lakes) across the Qiangtang Plateau (QTP) and identify the driving factors for its spatial variation. The δ13CDIC value of these observed lakes varies in the range of ? 15·0 to 3·2‰, with an average value of ? 1·2‰. The δ13CDIC value of closed lakes is close to the atmospheric isotopic equilibrium value, much higher than that in rivers and freshwater lakes reported before. The high δ13CDIC value of closed lakes is mainly attributed to the significant contribution of carbonate weathering in the catchment and the evasion of dissolved CO2 induced by the strong evaporation of lake water. The δ13CDIC value of closed lakes has a logarithmic correlation with water chemistry (TDS, DIC and pCO2), also suggesting that the evapo‐concentration of lake water can influence the δ13CDIC value. The δ13CDIC value shows two opposite logarithmic correlations with lake size depending on the δ13CDIC range. This study suggests that the δ13C in carbonates in lacustrine sediments can be taken as an indicator of lake volume variation in closed lakes on QTP. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
15.
阳澄湖若干水质资料的分析与评价 总被引：12，自引：0，他引：12
根据１９９４年５月于阳澄湖湖区７个采样点水质分析结果，表明湖水中矿化度较高，硬度较大，主要离子以ＨＣＯ３＾－，Ｎａ＾＋为主，分别占阴阳离子摩尔总数的５７．６１％、６３．９％。湖水水型西湖、中湖为重碳酸盐钠组Ⅰ型，东湖为重碳酸盐钠组Ⅱ型水。湖水中Ｎ、Ｐ营养元素丰富，ＮＨ３－Ｎ、ＮＯ２－Ｎ指标与７０年代相比明显增高，表明水体已曹室不程度地轻污染。 相似文献
16.
Study Area is located in the southwestern part of Bangalore South Taluk, Bangalore district, Karnataka state between 12°48??24.52?? to 12°53??59.85?? North latitude and 77°24??59.95?? to 77°30??6.72?? East Longitude. The major hydro-chemical facies that predominates in the study area is Ca2+-Mg2+-HCO 3 ? type during both pre- and post-monsoon seasons of the year 2007, could be as a result of dissolution of carbonate minerals like calcite and dolomite prevailing in the study area. However, cation-exchange processes could be responsible for the formation of the Ca2+-Mg2+-Cl?-SO 4 2? water type (??32%) from the CaSO4, MgCO3 and NaCl type that are formed due to the dissolution of anhydrite, gypsum, magnesite and halite. Besides, suitability of water for irrigation is evaluated based on sodium adsorption ratio, residual sodium carbonate, sodium percent, salinity hazard and USSL diagram. Hydrogeochemical speciation model calculations carried out using WATEQ4F program showed similar seasonal variation in the concentration of saturation indices of specific mineral phases, majority of the samples kinetically saturated with carbonate minerals (viz., aragonite, calcite and dolomite) indicating the influence of carbonate mineral phases on the chemistry of groundwater. On one hand, the samples were significantly oversaturated with Florapatite while on the other, they were undersaturated with respect to with anhydrite, gypsum and fluorite with halite being highly undersaturated. The Gibbs plots also gave an indication that there exists an interaction between rock and the percolating water into the subsurface by means of mineral dissolution. Factor analysis determined two factors mainly responsible for water quality during pre- and post-monsoon seasons, accounting to 52.84% and 51.09% of total variance respectively. Q-mode HCA Cluster analysis grouped the sampling stations into three clusters based on the similarity of water quality while R-mode HCA grouped analyzed parameters into two groups based on the effects of factors in the hydrochemistry. 相似文献
17.
B. Takano K. Suzuki K. Sugimori T. Ohba S. M. Fazlullin A. Bernard S. Sumarti R. Sukhyar M. Hirabayashi 《Journal of Volcanology and Geothermal Research》2004,135(4):299-329
A bathymetric survey of Kawah Ijen crater lake was conducted by acoustic sounding in 1996 to compare the lake morphology with those measured in 1922, 1925 and 1938, and to calculate the present lake volume. Even though the lake experienced several hydrothermal eruptions, the maximum depth became shallower (182 m) than before (200 m), resulting in a reduced lake volume (3.0×107 m3).Fifty-two major and minor constituents including rare earth elements and polythionates (PT) of the lake waters at various depths were determined by ICP-AES, ICP-MS and HPLC, respectively. These ions except for several volatile elements are taken up by lake fringe through congruent dissolution of pyroclastics of Kawah Ijen volcano. Most ions are homogeneously distributed throughout the lake, although PT showed a considerable vertical variation. Rare earth elements (REE) in the Kawah Ijen water as well as those from other hyper-acidic crater lakes show distribution patterns likely due to the three rock dissolution (preferential, congruent and residual) types, and their logarithmic concentrations linearly depend upon the pH values of the lake waters.Using the PT degradation kinetics data, production rates of PT, injection rates of SO2 and H2S into the lake were estimated to be 114, 86 and 30 tons/day, respectively. Also travel time of the spring water at the Banyupahit Riverhead from Kawah Ijen was estimated to be 600–1000 days through the consideration of decreasing rates of PT. Molten sulfur stocks containing Sn, Cu, Bi sulfides and Pb-barite exposed on the inner crater slope were presumed to be extinct molten sulfur pools at the former lake bottom. This was strongly supported by the barite precipitation temperature estimated through the consideration of the temperature dependence of Pb-chlorocomplex formation. 相似文献
18.
The fundamental assumption of 210Pb sediment dating is the stable flux of 210Pbex, which was derived from atmosphere and then transferred into sediments via lake water. When the sedimentation rate is relatively
constant, the 210Pbex activity in sediments will be exponentially reduced with sedimentation age. 210Pbex in lake water is incorporated into sediments mainly via organic particulates. If the sedimentation flux of organic matter
in lake water is suddenly increased, 210Pbex will be significantly deposited and then transferred into sediments. On the one hand such sudden purification effect is obviously
unfit for the fundamental assumption of 210Pb dating; on the other hand, the sudden enhancement of 210Pbex flux would be indicative of the conspicuous variation of primary productivity of lake water. This problem will be discussed
in accordance with the variation trend of 210Pbex in the vertical profile of recent sediments of Lake Chenghai, Yunnan Province. The sediment core was collected from the deep-water
area of Lake Chenghai in June 1997. The vertical profile of 137Cs activity is characterized by a tree-peak pattern. This profile gave reliable ages, and also showed the stability of sediment
accumulation in the recent ten years. The vertical profile of 210Pbex activity displays a specific distribution of peaks, and is similar to the vertical profile of Corg. This phenomenon seems to be related to the mechanism of constraining the transfer of 210Pbex into lake sediments. The average atomic ratios of Horg/Corg and Corg/Norg in Lake Chenghai sediments are 5.51 and 7.04, respectively, indicating that the organic matter was predominantly derived
from the remains of endogenic algae. In terms of the three-stage evolutionary characteristics of organic matter in sediments,
i.e., “deposition-de-composition-accumulation”, the sedimentation fluxes (F(Corg)) of organic carbon (Corg) since 1970 were calculated by modeling. The sedimentation fluxes of 210Pbex (F(210Pbex)) in different years display good synchronous relations with the sedimentation flux of organic carbon (F(Corg)), especially in the years of 1972–1974 and 1986–1989. The variation of F(Corg) led to the variation of F(210Pbex); the variation of F(210Pbex) reflects, to some extent, the historical variation of lake productivity. 相似文献