太湖流域降雨和湖水酸根阴离子长期变化及其环境意义

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SO₄^2-、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SO₄^2-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SO₄^2-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SO₄^2-/NO₃^-比值不断升高,远高于降水SO₄^2-/NO₃^-比值.研究认为：流域SO₂排放引起的酸沉降是湖水SO₄^2-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.     

Interactions between groundwater seepage and sediment porewater sulphate concentration profiles in lake anna,Virginia

Most sulphur diagenesis models predict that SO₄^2- concentrations decrease exponentially with increasing sediment depth and are lower than that of the overlying water throughout the sediments. Low SO₄^2- concentrations (less than 0.2 mM) are common in the sediments of Lake Anna that receive acid mine drainage; however, sediment with as much as 20 mM SO₄^2- at about 20cm below the sediment surface is also seen in this section of the lake. A decision tree was proposed to investigate the cause of the high SO₄^2- concentrations at depth (HSD) in the sediment. The first possibility proposed was that an increase in the quantity of groundwater flowing through Lake Anna sediments may increase groundwater advection of SO₄^2- or oxygen which would induce sulphide oxidation. This hypothesis was tested by measuring groundwater flow. HSD profiles were found in a discrete region of the lake; however, stations having these profiles did not have higher groundwater flow than other sites sampled. Alternate explanations for the HSD profiles were that the region in which they occurred had: (1) unusual sediment chemical compositions; (2) a different source of regional groundwater, or (3) a lateral intrusion of high SO₄^2- groundwater. There were no differences in sulphide and organic matter concentrations between the two regions. The area which has HSD in the sediment covers a large area in the middle of the lake, so it is unlikely that it has a unique source of regional groundwater. The third alternative was supported by the fact that in all three sample years, HSD stations were located in the preimpoundment stream channel, which is a likely lateral flow path for groundwater containing high SO₄^2- concentrations.     

Dissolved oxygen variations in alpine glacial meltwaters

Recent models of chemical weathering in alpine glacial meltwaters suggest that sulphide oxidation is a major source of solute in the distributed component of the subglacial hydrological system. This reaction requires O₂, and may lower dissolved oxygen levels to below saturation with respect to the atmosphere. This should result in an inverse association between SO₇^2- and dissolved oxygen saturation. However, measurements of O₂ saturation in bulk meltwaters draining the Haut Glacier d'Arolla, Switzerland, show that there is a positive association between SO₄^2- and O₂ saturation. The O₂ content of glacial meltwaters depends on the initial content of snow and icemelt, which may be controlled by the rate of melting, and the kinetic balance between O₂ losses (e.g. sulphide oxidation, microbial respiration) and gains (e.g. diffusion of O₂ into solution).     

The heterogeneous oxidation of SO2 on aerosol surface

A heterogeneous chemical model is developed by coupling aerosol, gas-phase and liquid-phase chemical model. SO₂ oxidation rates on the aerosol surface are calculated and the influence of some factors is discussed. Model simulations indicate that SO₂ heterogeneous oxidation rates are sensitive to the mass concentration and chemical composition of aerosols, relative humidity, initial values of SO₂ and H₂O₂. The heterogeneous chemical model is coupled with a Eulerian deposition model. Model results show that oxidation of SO₂ on the aerosol surface is found to reduce SO₂ levels by 5%–33%, to increase SO ₄ ^2- - concentrations by 8%–50% in the surface layer. Project supported by the National “85-912” Key Science and Technology Project.     

不同上覆水氟浓度对湖泊沉积物氟释放与微生物群落的影响

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SO₄^2-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,SO₄^2-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.     

Use of Hydrogeochemistry and Isotopes for Evaluation of Groundwater in Qilian Coal Base of China

The Jiangcang Basin is an important mining area of the former Qilian Mountain large coal base in Qinghai Province, and understanding the groundwater circulation mechanism is the basis for studying the hydrological effects of permafrost degradation in alpine regions. In this study, hydrogeochemical and multiple isotope tracer analysis methods are used to understand the chemical evolution and circulation mechanisms of the groundwater in the typical alpine region of the Jiangcang Basin. The diversity of the groundwater hydrochemistry in the study area reflects the complexity of the hydrogeochemical environment in which it is located. The suprapermafrost water and intrapermafrost water are recharged by modern meteoric water. The groundwater is closely hydraulically connected to the surface water with weak evaporation overall. The high δ³⁴S value of deep groundwater is due to SO₄ reduction, and SO₄²⁻-rich snow recharge with lixiviated sulfate minerals are the main controlling factor for the high SO₄²⁻ concentration in groundwater. According to the multivariate water conversion relationships, it reveals that the river receives more groundwater recharge, suprapermafrost water is recharged by the proportion of meteoric water, which is closely related to the mountainous area at the edge of the basin, while intrapermafrost water is mainly recharged by the shallow groundwater. This study provides a data-driven approach to understanding groundwater recharge and evolution in alpine regions, in addition to having significant implications for water resource management and ecological environmental protection in coal bases of the Tibetan Plateau.     

淮北临涣矿采煤沉陷区不同水体水化学特征及其影响因素

为研究淮北临涣矿采煤沉陷区不同水体的补给水源及溶质来源,在现场调查的基础上,系统采集丰水期、平水期、枯水期沉陷区积水、地表河水和浅层地下水样进行测试分析,采用Piper三线图、Gibbs图和因子分析方法,对不同水体水化学特征及其影响因素进行讨论.结果表明:地表水水体总溶解性固体(TDS)质量浓度表现为枯水期丰水期平水期,浅层地下水表现为枯水期平水期丰水期,地表水TDS质量浓度明显高于浅层地下水.地表水中主要阴阳离子为Na~+、Cl~-和SO_4~(2-),水化学类型主要为SO_4~(2-)-Cl~--Na~+型;浅层地下水离子以HCO_3~-、Ca~(2+)和Mg~(2+)为主,表现为HCO_3~--Ca~(2+)-Mg~(2+)型.结合Gibbs图和因子分析可知,地表水受蒸发作用、地表径流以及采煤活动等因素影响,浅层地下水在一定程度上体现出大气降水和地表水补给的特点,受岩石风化作用影响较为明显.     

Pollutant Concentrations in Mountain River Waters in the Upper Baksan Area (Prielbrus’e National Park) and Their Seasonal Variations

Materials of expedition studies in 2013 in the Prielbrus’e National Park were used to analyze the concentrations of a wide range of pollutants (SO₄^2-, Cl^?, Na⁺, K⁺, F^?, Mn, Cu, Zn, Pb, Cr, Ni, NO₃^-, NH₄⁺) in the water of mountain rivers forming the main artery of the region, the Baksan R. The analyzed data characterize seasonal variations in pollutant concentrations at seven sampling sections and their dynamics along the river down to the 35th km from the source in different seasons.     

Seasonal evolution of penitente glaciochemistry at Tapado Glacier,Northern Chile

This study uses stable isotopes and major ions to examine the seasonal evolution of penitentes on the surface of Tapado Glacier, in the Norte Chico region of the Chilean Andes. A snow pit was sampled in November 2011, and penitentes were sampled during the summer (December 2011 and January 2012). The major ion load of the winter snowpack is dominated by Ca²⁺ (60%), SO₄^2? (16%) and NO₃^? (13%), and there is little influence from marine air masses at the site, with most SO₄^2?, Mg²⁺, Ca²⁺ and Na⁺, derived from non‐sea salt sources. During the early ablation season we observe increases in stable isotope ratios and major ion concentrations (particularly lithic ions Na⁺, Mg²⁺ and Ca²⁺) in the upper reaches of penitentes, which is attributed to sublimation and the aeolian deposition of dust particles. In the late‐summer, melt replaces sublimation as the dominant ablation process and results in smoothing of the stable isotope profile and the elution of major ions within the penitente snow and ice matrix. Copyright © 2015 John Wiley & Sons, Ltd.     

三峡大坝上下游水质时空变化特征

为探索三峡大坝上下游（坝上99.9 km、坝下63.0 km、全长162.9 km）水质时空变化特征,运用主成分分析和方差分析对2016年近坝段水质时空变化特征进行了分析.主成分分析表明,水文因子流量（Q）、气温（T）、水位（Z）和水质因子（水温（WT）、pH、电导率（EC）、溶解氧（DO）、悬浮物（SS）、高锰酸盐指数（COD_Mn）、硫酸盐（SO₄^2-）、氟化物（F^-）、总硬度（T-Hard）、硝态氮（NO₃^--N）、总氮（TN）和硒（Se））的变化主导着研究区域水质变化;各采样点主成分得分和双因素方差分析结果显示研究区域水质因子时间变化主要呈现出季节和不同水库运行时期的差异.消落期（2-5月）,T-Hard、F^-、SO₄^2-和EC是影响河流水质变化的主导因子;汛期（7-8月）,Q、SS、COD_Mn、NO₃^--N、TN和Se是影响河流水质变化的主导因子;T和WT主导着汛末（9月）河流水质变化,并引起了DO等理化特性的变化;高水位运行期（12月）,Cl^-是影响河流水质变化的主导因子.现阶段,DO、有机污染物（COD_Mn）、无机盐（SO₄^2-和F^-）、营养盐类（NO₃^--N和TN）、类金属元素（Se）和水体的矿化程度（T-Hard）的变化主导着区域水质的变化,是三峡大坝近坝段水域水质的控制因子.方差分析表明,河流的理化特性（DO、pH和SS）、营养盐组分构成（NH₃-N和NO₃^--N）、无机盐类（EC和Cl^-）、石油类有机污染物及粪大肠菌群（FC）等指标在坝上与坝下断面存在显著性差异.气温、水温、降雨、含沙量的季节性影响因素和水库调度运行模式是影响近坝段水质时间差异的主要因子;空间差异主要受城区污染排放和三峡水库调度引起的坝上和坝下水文和水动力学条件差异影响.因此控制研究区域因人类活动等造成的外源性污染,并针对不同类污染物质的季节变化特征实施合理的水库运行方式是近坝段水质提升的关键.     

Spatial and temporal patterns of snow accumulation and aerial ablation across the McMurdo Dry Valleys,Antarctica

Snow in the McMurdo Dry Valleys is a potential source of moisture for subnivian soils in a cold desert ecosystem. In a water‐limited environment, enhanced soil moisture is expected to provide more favourable conditions for subnivian soil communities. In addition, snow cover insulates the underlying soil from air temperature extremes. Quantifying the spatial and temporal patterns of seasonal snow accumulation and ablation is necessary to understand these dynamics. Repeat high‐resolution imagery acquired for the 2009–2010 austral summer was used to map the seasonal distribution of snow across Taylor and Wright valleys, Southern Victorialand, Antarctica. An edge detection algorithm was used to perform an object‐based classification of snow‐covered area. Coupled with topographic parameters obtained from a 30‐m digital elevation model, unique distribution patterns were characterized for five regions within the neighbouring valleys. Time lapses of snow distribution in each region provide insight into spatially variable aerial ablation rates (change in area of landscape covered by snow) across the region. A strong coastal to interior gradient of decreasing snow‐covered area was evident for both Taylor and Wright valleys. The surrounding regions of Lake Fryxell, Lake Hoare, Lake Bonney, Lake Brownworth, and Lake Vanda exhibited losses of snow‐covered area of 9.61 km² (?93%), 1.63 km² (?72%), 1.07 km² (?97%), 2.60 km² (?82%), and 0.25 km² (?96%), respectively, as measured from peak accumulation in October to mid‐January. Differences in aerial ablation rates within and across local regions suggest that both topographic variation and regional microclimates influence the ablation of seasonal snow cover. Copyright © 2012 John Wiley & Sons, Ltd.     

Hydrochemical characteristics and water quality of the Mušnica River catchment,Bosnia and Herzegovina

Abstract

The spatial position of the Mu?nica River catchment in the Dinaric Karst results in specific conditions of the drainage, distribution and chemical characteristics of the surface water and groundwater. This catchment is mountainous, located between 930 and 1985 m above sea level. The chemical characteristics of the waters are strongly dependent on the local lithological composition and the precipitation regime. The dominant cations are Ca²⁺ and Mg²⁺, and anions HCO₃ ^- and SO₄ ^2-. The surface water is characterized by low and medium mineralization, with resultant soft, medium-hard and very-hard total hardness levels. The groundwater is more mineralized than the surface water. Gacko Town and its associated thermal power plant, Gacko 1, which are located in the southern part of the Mu?nica River catchment, have no modern facilities for sewage and wastewater transport or treatment. In order to prevent further water quality deterioration and to enable its sustainable use, it is recommended to ensure adequate protection measures in the catchment area.

Editor Z.W. Kundzewicz; Associate editor S. Faye

Citation Banjak, D. and Nikoli?, J., 2012. Hydrochemical characteristics and water quality of the Mu?nica River catchment, Bosnia and Herzegovina. Hydrological Sciences Journal, 57 (3), 562–575.     

Snow and stream-water chemistry of the Ganga headwater basin,Garhwal Himalaya,India

Abstract

Studies of the chemical composition of snowpack and stream water were carried out in a catchment having an area of 53km² (31°03′-30°55′N and 78°40′-78°51′E) in the Garhwal Himalaya, India. The dominant ions in the snowpack and stream water were Ca²⁺, Na⁺, NO^? ₃, SO^2- ₄ and HCO^? ₃. Solute patterns in the snowpack show preferential elution. Investigation of the chemical composition of stream water shows that meltwater changes its composition substantially as it passes through soil pathways to the stream. The groundwater flushing perhaps controls the chemical composition of meltwater in the early spring. However, in the period from July to September, the stream water carries the chemical signature of monsoonal precipitation.     

Evaluation and bias correction of SNODAS snow water equivalent (SWE) for streamflow simulation in eastern Canadian basins

ABSTRACT

In snow-dominated basins, collection of snow data while capturing its spatio-temporal variability is difficult; therefore, integrating assimilation products could be a viable alternative for improving streamflow simulation. This study evaluates the accuracy of daily snow water equivalent (SWE) provided by the SNOw Data Assimilation System (SNODAS) of the National Weather Service at a 1-km² resolution for two basins in eastern Canada, where SWE is a critical variable intensifying spring runoff. A geostatistical interpolation method was used to distribute snow observations. SNODAS SWE products were bias-corrected by matching their cumulative distribution function to that of the interpolated snow. The corrected SWE was then used in hydrological modelling for streamflow simulation. The results indicate that the bias-correction method significantly improved the accuracy of the SNODAS products. Moreover, the corrected SWE improved the simulation performance of the peak values. Although the uncertainty of SNODAS estimates is high for eastern Canadian basins, they are still of great value for regions with few snow stations.     

柴达本盆地沙下盐湖的卤水化学及矿物沉积特征——以察尔汗盐湖区北部外围地带为例

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⁺+SO₄^2-、贫K⁺+CO₃^2-+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。     

What can be deduced from chemical measurement in an open-field raingauge? An example in the Maures Massif,southeastern France

Abstract

The deposition of chemical elements in a catchment occurs through three different processes: wet, dry and cloud deposition. Total deposition cannot be inferred from measurements made with open-field raingauges, and still constitutes a challenge to scientific method. The chemical composition of samples from an open-field raingauge (bulk precipitation) was analysed over a period of several years in a small Mediterranean catchment in the Maures Massif, France. The input of chloride measured in this way was two times lower than the output, despite the fact that this element is reputed to be conservative, which means input and output should roughly balance. This implies that input has previously been underestimated. Analysis of the bulk precipitation data was carried out taking into account both the history of rain events and of sampling. This study allowed the relative parts of the different deposition processes to be quantified. Dry deposition can provide from 20% to more than 80% of the anthropogenic and terrigenic elements (Ca²⁺, Mg²⁺, K⁺, NO₃ ^?, SO₄ ^2-, SiO₂) to the rain samples. The occult deposition of marine elements on the catchment area (50% of total deposition) was found to be mostly due to cloud deposition during wet periods.     

Trace element and major ion concentrations and dynamics in glacier snow and melt: Eliot Glacier,Oregon Cascades

We present concentrations of environmentally available (unfiltered acidified 2% v/v HNO₃) As, Cu, Cd, Pb, V, Sr, and major ions including Ca²⁺, Cl^?, and SO₄^2? in a July 2005 and a March 2006 shallow snow profile from the lower Eliot Glacier, Mount Hood, Oregon, and its proglacial stream, Eliot Creek. Low enrichment factors (EF) with respect to crustal averages suggests that in fresh March 2006 snow environmentally available elements are derived primarily from lithogenic sources. Soluble salts occurred in lower and less variable concentrations in July 2005 snow than March 2006. Conversely, environmentally available trace elements occurred in greater and more variable concentrations in July 2005 than March 2006 snow. Unlike major solutes, particulate‐associated trace elements are not readily eluted during the melt season. Additionally, elevated surface concentrations suggest that they are likely added throughout the year via dry deposition. In a 1‐h stream sampling, ratios of dissolved (<0·45 µm) V:Cl^?, Sr:Cl^?, and Cu:Cl^? are enriched in the Eliot Stream with respect to their environmentally available trace element to Cl^? ratios in Eliot Glacier snow, suggesting chemical weathering additions in the stream waters. Dissolved Pb:Cl^? is depleted in the Eliot Stream with respect to the ratio of environmentally available Pb to Cl^? in snow, corresponding to greater adsorption onto particles at greater pH values. Copyright © 2009 John Wiley & Sons, Ltd.     

HYDROCHEMISTRY AS AN INDICATOR OF SUBGLACIAL DRAINAGE SYSTEM STRUCTURE: A COMPARISON OF ALPINE AND SUB-POLAR ENVIRONMENTS

The anion compositions (SO²₄, HCO⁻₃ and Cl⁻) of runoff from the Haut Glacier d'Arolla, Switzerland and Austre Brøggerbreen, Svalbard are compared to assess whether or not variations in water chemistry with discharge are consistent with current understanding of the subglacial drainage structure of warm- and polythermal-based glaciers. These glacial catchments have very different bedrocks and the subglacial drainage structures are also believed to be different, yet the range of anion concentrations show considerable overlap for SO²⁻₄ and HCO⁻₃. Concentrations of Cl⁻ are higher at Austre Brøggerbreen because of the maritime location of the glacier. Correcting SO²⁻₄ for the snowpack component reveals that the variation in non-snowpack SO²⁻₄ with discharge and with HCO⁻₃ is similar to that observed at the Haut Glacier d'Arolla. Hence, if we assume that the provenance of the non-snowpack SO²⁻₄ is the same in both glacial drainage systems, a distributed drainage system also contributes to runoff at Austre Brøggerbreen. We have no independent means of testing the assumption at present. The lower concentrations of non-snowpack SO²⁻₄ at Austre Brøggerbreen may suggest that a smaller proportion of runoff originates from a distributed drainage system than at the Haut Glacier d'Arolla.     

新疆艾比湖干涸湖底不同景观单元蒸发盐分布与变化特征

盐尘暴是由干旱、半干旱区尾闾湖干涸湖底及其附近盐质荒漠风蚀所导致的一种灾害性极强的天气现象.盐尘主要来自风蚀过程中干涸湖底盐分的释放.由于干涸湖底不同的植被覆盖状况,导致风蚀过程中盐分损失不同.为了解风蚀过程中不同景观单元下盐分分布与变化特征,选择艾比湖干涸湖底自然状态下典型的6种景观单元(胡杨林带(Landscape 1,简写为L1)、乔本结合带(L2)、草本结合带(L3)、芦苇荒漠带(L4)、梭梭荒漠带(L5)、无植被覆盖(L6)),于2011年6月初和10月初2次采集沉积物样品,运用方差分析方法,研究各个景观单元下盐分的分布与季节变化特征.结果表明:1)2次采样不同景观单元0~30 cm和30~60 cm处阳离子Na⁺、K⁺、Mg²⁺含量均存在显著差异,其中Na⁺含量存在极显著差异且含量最高,而不同景观单元0~30 cm和30~60 cm处阴离子Cl^-、SO₄^2-含量均存在显著差异,CO₃^2-、HCO₃^-含量甚微;2)干涸湖底沉积物的主要盐分类型是NaCl,其次是CaSO₄,其它盐分含量较小,且不同景观单元相同深度沉积物盐分含量存在显著差异.无论是盐分离子组成还是含量,L5均最高,其次是L6,而L2均最低.随着深度的增加,不同景观单元沉积物中的盐分含量均呈现降低的趋势.随着时间变化,景观单元L2、L3、L4、L5、L6盐分含量有不同程度的增加,而L1盐分含量减少;3)在小尺度范围内,局地气候条件相对均一,地下水矿化度、地下水埋深及沉积物性质差别不大,不同景观类型是影响盐分表聚的主要因素.     

Hydrological sciences—society's needs

Abstract

The hydrological regime of a mountainous catchment, in this instance the Mesochora catchment in Central Greece, was simulated for altered climates resulting when using the Goddard Institute for Space Studies (GISS) model for carbon dioxide doubling. The catchment snow water equivalent was predicted on the basis of the snow accumulation and ablation model of the US National Weather Service River Forecast System (NWSRFS), while the catchment runoff, as well as actual evapotranspiration and soil moisture storages, were simulated through application of the soil moisture accounting model of NWSRFS. Two scenarios of monthly climate change were drawn from the GISS model, one associated with temperature and precipitation changes, while the other referred to temperature changes alone. A third hypothetical scenario with temperature and precipitation changes similar to those corresponding to the mean monthly GISS scenarios was used to test the sensitivity of the monthly climate change of the hypothetical case on catchment hydrology. All three scenarios projected decreases in average snow accumulations and in spring and summer runoff and soil moisture, as well as increases in winter runoff and soil moisture storage and spring evapotranspiration.