首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 203 毫秒
1.
基于氢氧同位素与水化学的潮白河流域地下水水循环特征   总被引:24,自引:1,他引:23  
为了研究变化环境下潮白河流域地下水水循环规律,通过现场调查,结合环境同位素及水化学应用,对潮白河流域浅层和深层地下水采样,测定其氢、氧环境同位素及水化学成分,通过分析其变化特征判明地下水的补给来源以及各含水层的相互联系。降水和地下水中的环境同位素δD和δ18O组成分析表明,降水是山前地下水的主要补给源,山区浅层地下水受蒸发影响非常强烈。水化学研究结果表明,山区地下水水质以 Ca2+和 HCO-3为主,属Ca2+-Mg2+-HCO-3型地下水。山前地下水类型为Ca2+-Mg2+-HCO-3、 Na+-K+-HCO-3、Mg2+-Ca2+-HCO-3和 Ca2+-Mg2+-Cl--SO2-4。平原区地下水为Mg2+, Na+和HCO-3。滨海冲积海积平原为Ca2+-Mg2+-HCO-3型和Ca2+-Mg2+-Cl--SO2-4型地下水。水化学分析证实了越流补给的存在。Ca2+ 和 HCO-3离子均呈山区高、山前和平原低、而滨海增高的趋势。沿潮白河流向地下水类型变化为:Ca2+-Mg2+-HCO-3 Na+=K+-HCO-3 Ca2+-Mg2+-HCO-3。  相似文献   

2.
The present work are extract cesium (Cs+) and rubidium (Rb+) from the salt lake brine containing the potassium (K+) and magnesium (Mg2+) after concentrated through evaporation. It has excellent effect of extraction that 4-sec-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) was diluted in the Sulfonated Kerosene (SK). The infrared spectrum studies indicate that polymerize to form the dimer in the t-BAMBP when Cs+ or Rb+ were extracted. The effect of K+ and Mg2+, t-BAMBP concentration, the volume ratio of organic phase to aqueous phase (O/A) and the alkalinity(pH) of aqueous phase were investigated. The K+ and Mg2+ should be eliminated through precipitation before extraction and separation Cs+ and Rb+. The experimental brine was extracted of optimum conditions were using 0.8 mol/L t-BAMBP in SK, the pH exceed 13, and O/A of 1:1 for 2 min contact time under room temperature. The optimal extraction yields of Cs+ and Rb+ up to 100% and 85.8%, and 8.76% K+ was co-extracted. Further work target to increase theSextractionSyield and selectivity ofSRb+, and realize the efficient seperation of Cs+ and Rb+ products .  相似文献   

3.
松嫩平原西部盐沼湿地水环境化学特征   总被引:10,自引:1,他引:9  
邓伟  何岩  宋新山  阎百兴 《地理研究》2000,19(2):113-119
松嫩平原西部盐沼湿地水环境碱化程度高,水中的pH值普遍高于8.0,多数为苏打钠型水。在对本区盐沼基本水环境化学特征阐述的基础上,通过对水化学的基本变量CO32-、HCO32-、Cl-、Ca2+、Mg2+、SO42-、Na+和派生变量(Cl-+SO42-)/HCO32-及Na+/(Ca2+ Mg2+)等的相关分析,得出各水化学变量之间的相关关系,并以pH值为分类基础得到了判别函数和判别区域图,对区域盐沼湿地水环境化学特征的研究方法作出了有意义的尝试。  相似文献   

4.
气候变化对河北省海河流域径流量的影响   总被引:2,自引:0,他引:2  
邵爱军  左丽琼  王丽君 《地理研究》2010,29(8):1502-1509
利用河北省境内海河流域51个气象站、68个水文站1956~2000年近50年的气象、径流量数据,分析了气象要素和径流量的变化规律。河北省境内海河流域多年平均地表径流量为67.0×108m3,从20世纪 50 年代至 90 年代地表径流量呈逐渐减小的趋势,50年代为105.3×108m3,90年代为54.7×108m3。地表径流量随降水量的减少而减小,随气温的升高而下降,用回归方法建立的径流量与气象要素之间的模型为对数模型。根据未来气候变化情景对河北省海河流域径流量的预测:2030年为70.0~76.8×108m3,2050年为69.8~76.9×108m3。  相似文献   

5.
210Pb、137Cs 计年法已被国内外广泛用于湖泊、河流和海洋现代沉积速率的研究中。本文在 回顾了210Pb、137Cs 计年法应用于海岸带沉积速率研究的现状以及存在问题的基础上, 根据海岸带 沉积环境特征分析了210Pb、137Cs 计年法在应用中应当注意的问题, 包括采样精准性, 样品分离的 分辨率, 数据校正方法的选择及两种方法的相互印证等。从几个方面探讨了提高沉积速率测定精 度的可能性, 同时指出, 210Pb、137Cs 的扩散混合模型的建立, 137Cs 沉积滞后的问题, 以及137Cs、210Pb 计年法的应用范围等仍有待深入探讨。  相似文献   

6.
渭河关中段洪水资源化潜力评估   总被引:6,自引:2,他引:4  
李景宜  石长伟  傅志军  赵昕 《地理研究》2008,27(5):1203-1211
洪水资源化是实施渭河流域关中段流域资源综合管理和实现区域经济可持续发展的必然要求和重要途径。通过对渭河流域关中段来水来沙丰枯变化规律和河道冲淤特性的分析,从有利于输水输沙减少泥沙淤积考虑,确定渭河中游洪峰2000m3/s、渭河下游段3000m3/s为洪水利用起算标准;依据这一标准,计算出林家村—魏家堡河段平均年可利用洪水水量、洪水沙量分别为4.038×107m3、6.83×106t,魏家堡—咸阳河段平均年可利用洪水水量、洪水沙量分别为为9.139×107m3、6.05×106t,咸阳—华县河段平均年可利用洪水水量、洪水沙量分别为1.617×108m3、1.843×107t;流域综合管理过程中,必须引入风险管理机制,利用优化理论寻找平衡机制,实现流域防洪、供水和生态保护兼顾的最佳效益。  相似文献   

7.
为研究内陆盐沼植物群落的分布对土壤盐分的响应特征,选取鄂尔多斯盐湖盐沼区作为研究区,筛选了肉质耐盐植物群落,苔草植物群落和禾草植物群落3类典型植物群落,开展了土壤含水量、pH、电导率以及Na+,K+,Mg2+,Ca2 +,Cl-、SO42-、CO32-和HCO3-的测定,分析了区内典型植物群落对土壤水盐因子的响应规律。探讨了3类植物群落之间土壤因子含量的差异性;采用相关性分析和CCA分析,评价了3类植物群落多样性及物种分布随土壤因子的变化规律。结果表明,区内3类植物群落中,土壤盐分含量表现为肉质耐盐植物群落最高,苔草植物群落最低,禾草植物群落居中;植物多样性与土壤中含量最高的Na+和SO42-的相关性最显著;植物分布同时受到土壤盐分、水分和pH的显著影响。研究结果可为鄂尔多斯盐湖区土壤盐渍化改良和植被恢复提供理论支撑。  相似文献   

8.
锡林河流域羊草草原暗栗钙土矿质氮动态变化   总被引:7,自引:0,他引:7  
通过野外采样,分析了内蒙古锡林河流域三个不同放牧强度羊草草原0~30cm表层土壤中矿质氮(NH4+-N+NO3--N)的浓度特征,研究了它们在生长季期间的含量变化情况。结果表明:羊草草原暗栗钙土中矿质氮主要以NH4+-N形式存在,矿质氮含量仅占土壤全氮的0.20%~0.92%;土壤矿质氮含量随草地放牧强度升高而降低,围封禁牧多年的羊草样地矿质氮含量高于轮牧地和自由放牧地;生长季期间0~10cm、10~20cm和20~30cm各层次土壤NH4+-N和NO3--N含量随土壤温度、水分和植物生长吸收的变化而波动明显,不同深度土壤矿质氮的季节变化趋势基本一致,表层0~10cm土壤矿质氮含量波动幅度最大:在4月和7、8月份,NO3--N和NH4+-N浓度分别出现峰值;NH4+-N和NO3--N含量随采样深度增加而降低,各采样点0~30cm土壤中NH4+-N含量均高于NO3--N。  相似文献   

9.
旅游业发展综述阿尔泰(阿尔泰一词来自蒙语阿尔坦,意为黄金)边区位于俄罗斯西西伯利亚经济区,国土面积26.17×104km2,西北-东南距离950 km,人口277.77万人,其中山地阿尔泰自治省面积9.26×104km2,人口17.98万人。  相似文献   

10.
内蒙古西部地区盐湖水化学特征   总被引:2,自引:1,他引:2       下载免费PDF全文
2008年9~10月和2009年9月对内蒙古西部地区14个盐湖进行了考察、采样和分析。研究发现,本区盐湖卤水主要离子含量顺序为Na+>Cl->SO2-4>Mg2+>K+,次要离子为Ca2+ >HCO-3>CO2-3,微量元素为B2O3>Br->Li+。Na+的分布特征为东部高,北部中等,西南部偏低;而Cl-为东高西低;K+大致为南高北低;Mg2+为中部高,西部低,北部与南部中等。SO2-4、 Ca2+和CO2-3的区域分布特征均不明显;微量元素Li+ 、Br-、B2O3含量虽局部(两大沙漠连接带)有所富集,但绝对含量不高。对天然盐湖和人工采盐池的卤水进行了对比。采盐池中卤水因为蒸发强烈,离子浓度显著高于天然盐湖。分析天然盐湖与采盐池卤水离子浓度的变化规律发现,卤水蒸发初期Na+、Cl-、SO2-4离子浓度随矿化度的升高而增大,Ca2+离子浓度明显下降,卤水蒸发后期Mg2+、K+大量富集,整个卤水蒸发过程中微量元素Li+与B2O3浓度一直随矿化度的升高而增大。这些结果对内蒙古西部盐湖的研究与开发都具有积极意义。  相似文献   

11.
叶祥清 《地理研究》1983,2(2):82-87
本文介绍了应用碳化理(Li2C2)法进行化学制样测定14C年代获得成功的试验.抑制鋰的升华作用是成功的关键.文中提出了改革鋰反应器冷却装置的根据和方案.试验结果是令人满意的.从CO2到C2H2的转化中碳的收率高达98%(而StC2法为70%左右).本文发表了40个14C年代数据,其中4个进行了互校对比,一致性很好.  相似文献   

12.
The objective of this study is to outline how the ground-water quality is affected by geological factors, soil characteristics and subsurface structure. The results of 25 ground-water samples, and 30 soil samples of which 10 soil samples analysed chemically provide the basis of this study. Procedures to interpret water quality data are based on a combined use of the traditional graphical methods, ratios of Na+/Cland Ca2+/Mg2+, multivariate geostatistical methods and computation of the saturation indices (SI) of minerals. The results of soil analyses show that the grain size ranges from very coarse sand to clayey loams, and from well sorted and extremely poorly sorted. The soil salinity increases in old alluvial plains and decreases in the dissected wadis of limestone plateaux, while vertical distribution decreases with depth. It is found that the ground-water is supersaturated with respect to calcite and dolomite, and undersaturated with respect to gypsum. Calculated values of PCO2for the ground-water samples range from 2×10−4to 7×10−3with a mean value of 3×10−3(atm.). This indicates that the ground-water becomes charged with CO2during infiltration processes.  相似文献   

13.
非点源污染研究中土壤溶解性无机氮的提取方法选择   总被引:6,自引:0,他引:6  
王红萍  梁涛  张秀梅  夏军 《地理研究》2005,24(2):236-242
用2M KCl溶液(5:1)、饱和CaSO4溶液(5:1)、0.01M CaCl2溶液(20:1,100:1) 和去离子水(20:1,100:1)4种提取液、6种提取方式,采用Auto-analyzerⅢColorimeter (Bran Luebbe),水杨酸-次氯酸盐法和Griess-Ilosvay法测定并对比了北京地区4种天然土样的溶解性氨氮和硝态氮的含量。研究结果表明:溶解性硝态氮的测定结果不受提取液和水土比(小于100:1)的影响,而溶解性氨氮测定结果受影响较大。在非点源污染研究中,对于土壤中可向水体迁移的溶解性无机氮含量的测定,应根据来水水源特征和研究目的选择适宜的浸提剂和水土比。  相似文献   

14.
Aerosol samples were collected in the Shiyi Glacier,Qilian Mountains from July 24 to August 19,2012 and analyzed for major water-soluble ionic species(F-,Cl-,NO2-,NO3-,SO42-,Na+,NH4+,K+,Mg2+ and Ca2+) by ion chromatography. SO42- and NH4+ were the most abundant components of all the anions and cations,with average concentrations of 94.72 and 54.26 neq/m3,respectively,accounting for 34% and 20% of the total water-soluble ions analyzed.These mean ion concentrations were generally comparable with the background conditions in remote sites of the Qilian Mountains,but were much lower than those in certain cities in China.The particles were grouped into two dominant types according to their morphology and EDX signal:Si-rich particles and Fe-rich particles.Backward air mass trajectory analysis suggested that inland cities may contribute some anthropogenic pollution to this glacier,while the arid and semi-arid regions of central Asia were the primary sources of the mineral particles.  相似文献   

15.
采用动态密闭气室法测定分析了科尔沁沙地典型玉米(Zea mays)农田垄上和垄间土壤呼吸速率的差异及自养和异养呼吸特征,并估算了生态系统碳平衡。结果表明:(1)垄上和垄间土壤呼吸速率存在极显著差异(p0.001),且存在线性关系(p0.05);季节水平上垄上土壤呼吸可解释垄间土壤呼吸98.4%的变异。(2)季节水平上土壤总呼吸(RS)、异养呼吸(RH)和自养呼吸(RA)的温度敏感性指数Q10大小顺序为:RA(4.35)RS(3.10)RH(2.08)。(3)RS和RH之间存在显著差异,RA与RS和RH之间不存在显著差异;RA占RS比例的季节变化范围为28.1%~71.1%,生长季RH和RA占RS的比例均值分别为44.4%和55.6%。(4)科尔沁沙地典型农田生态系统在生长季为碳汇,可净固存大气CO2-C的量为659.1g·m-2。  相似文献   

16.
Sediments are typically analyzed for C, N, and P for characterization, sediment quality assessment, and in nutrient and contaminant studies. Cost and time required for analysis of these constituents by conventional chemical techniques can be limiting factors in these studies. Determination of these constituents by near-infrared reflectance spectroscopy (NIRS) may be a rapid, cost-effective method provided the technology can be applied generally across aquatic ecosystems. In this study, we explored the feasibility of using NIRS to predict total C, CO3 –2 organic C, N, and P in deep-water sediment cores from four Canadian lakes varying over 19 degrees of latitude. Concentration ranges of constituents in the samples (dry weight basis) were total C, 12-55; CO3 –2, 6-26; organic C, 7-31; N, 0.6-3.1; and P, 0.22-2.1 mg g–1. Coefficients of determination, r2, between results from conventional chemical analysis and NIR-predicted concentrations, based on calibrations across all the four lakes, were 0.97-0.99 for total C, organic C, and N. Prediction for CO3 –2 was good for the hard water lake from a calibration across all four lakes, but this constituent in the three soft water lakes was better predicted by a calibration across the soft water lakes. The NIR calibration for P fell below acceptable levels for the technique, but proved useful in the identification of outliers from the chemical method that were later removed with the re-analysis of several samples. This study demonstrated that NIRS is useful for rapid, simultaneous, cost-effective analysis of total C, CO3 –2, organic C, N, and P in dried sediments from lakes at widely varying latitudes. Also, this study showed that NIRS is an independent analytical tool useful for the identification of outliers that may be due to error during the analysis or to distinctive composition of the samples.  相似文献   

17.
中国内陆干旱、半干旱区苦咸水分布特征   总被引:1,自引:0,他引:1  
通过大量野外调查、水样采集和化验分析,对中国内陆干旱、半干旱区的苦咸水和高氟水分布特征进行了初步研究。采集到的地表和地下水样中,分别有51.0%和41.5%属于苦咸水;55%和59%水样氟化物含量超标,属于高氟水。研究区的苦咸水以Cl--Na+和HCO3--Na+为主要离子类型,SO42--Mg2+和SO42--Ca2+为次要离子类型。苦咸水和高氟水主要分布在内陆河流域下游尾闾、封闭内流区低洼湖盆低地、北部准平原化干燥剥蚀低山残丘间冲积洼地、沙漠低洼湖盆和黄土高原中西部径流系数较小的河流及部分露头潜水等区域,并具有区域富集性分布特点。季节性降水、季节性河流或渠系灌溉对苦咸水的季节性或年际间变化和空间分布有较大影响。较高浓度基质含盐量、水文地质结构、气候条件和特定的水文地球化学环境是苦咸水和高氟水形成与富集分布的主要原因。  相似文献   

18.
赣江上游河流水化学的影响因素及DIC来源   总被引:20,自引:0,他引:20  
对赣江上游38 处水体采样点的水化学特征和溶解无机碳稳定同位素的分析, 发现其总溶解质浓度较低, 其中, 阳离子以Na+、Ca2+ 为主, 阴离子以Cl- 和HCO3 - 为主, Si 的浓度较高, 表征了典型硅酸盐地区河流的水化学组成特征。通过海盐校正分析得出, 研究区大气降水对河水溶解质的贡献率为11.5%, 扣除降水的贡献部分, 利用主成分分析的方法, 计算得出赣南流域受硅酸盐岩风化作用强烈, 同时由于受附近盐矿的影响, 蒸发盐岩的风化作用显著。另外, 根据δ13C 溶解无机碳DIC 的测量值约为-8.35‰~-13.74‰, 平均为-11.65‰, 利用质量平衡计算得出, 研究区DIC 的主要来源, 约68.5%来自于土壤CO2, 31.5%来自于碳酸盐矿物的溶解, 进而得出流域岩石化学风化过程消耗的土壤CO2 为2.11×105 mol/yr·km2, 来自碳酸盐本身的HCO3 -含量为9.6×104 mol/yr·km2。由于地理位置和流域环境以及人为因素的差异, 各支流DIC 来源的比例亦有所差异。  相似文献   

19.
A sedimentary record of human disturbance from Lake Miragoane,Haiti   总被引:1,自引:0,他引:1  
Lake Miragoane, Haiti is one of the largest, natural freshwater lakes in the Caribbean (A=7.06 km2, zmax=41.0 m, conductivity = 350 S cm–1). Lake waters are dominated by calcium and bicarbonate ions. The lake was thermally stratified, and oxygen profiles were clinograde during summer visits in 1983 and 1985. A 72-cm mud-water interface core was taken near the center of the lake and dated with 210Pb. The local 210Pb fallout rate is low (0.09 pCi cm–2 yr–1), about 20% of the global average. Bulk sedimentation rates ranged from 0.008 to 0.030 g cm–2 yr–1 during the past 130 years (0–8 cm depth). Sediment geochemistry and pollen have been analyzed in the topmost 58 cm of the section. Tentative ages were assigned to the core by extrapolation of 210Pb dates. According to this preliminary chronology, the bottom part of the core (58–30 cm) records pre-Columbian sedimentation (1000–500 B.P.) and contains pollen evidence of intact, dry and mesic forest. Pre-Columbian deposits are rich in organic matter (x = 30%) and relatively poor in carbonates (x = 15% as CO2). The top 30 cm of the core preserve the record since European contact (500 B.P. to present). Pollen data reveal two episodes of deforestation following European arrival. Consequent soil erosion is documented by a decrease in organic matter content (x = 15%) and an increase in carbonates (x = 27% as CO2). Surficial sediments reflect the widespread deforestation and soil loss that characterize the watershed today.  相似文献   

20.
Recent investigations of aeolian transport have focused on increasingly short time scales because of growing recognition that wind unsteadiness is a major factor in the dynamics of sediment transport. However, the statistical reliability of shear velocity (u*) estimates becomes increasingly uncertain as averaging interval is decreased. This study provides an empirical assessment of the influence of averaging interval on the reliability of u* estimates. The data consist of 15-min wind-speed profiles (1 Hz sampling) collected at four coastal sites. Each profile was subdivided into progressively shorter fixed-length time intervals, and estimates of u* and the 95% confidence interval for u* were determined for each time-block using standard statistical techniques.The logarithmic model accurately represents the measured wind-speed profiles, even with relatively brief averaging intervals. Mean r2 values remain robust down to block lengths as short as 10–20 s, typically retaining better than 98% of the r2 value found for the full-length data sets. Fewer than 2% of the individual 10-s blocks had r2 values less than 0.9. However, mean confidence intervals typically expanded by 70–80% of the full-record value as block length decreased from 900 to 10 s. For highly log-linear profiles, this amounted to an absolute increase from about ±8% to only ±14% of u*, so that the additional information gained through the use of shorter averaging intervals may outweigh the increase in statistical uncertainty. Nevertheless, given that rates of aeolian transport are generally modeled as a function of u*3, this increase in uncertainty may be significant for transport modeling. Thus, very short averaging intervals should be used with caution when predicting aeolian sediment flux. It is proposed that transport modeling should incorporate the shear velocity confidence interval as an indicator of the potential error associated with this source of uncertainty.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号