诺木洪河流域地下水水化学特征及演化规律研究

【目的】对青海省诺木洪河流域地下水水化学特征及演化规律进行研究,为合理开发和保护该地区地下水提供指导。【方法】采集诺木洪河流域具有代表性的水样58个,测定水样中的Na~+、K~+、Ca~(2+)、Mg~(2+)、HCO_3~-、Cl~-、SO_4~(2-)、CO_3~(2-)、矿化度等指标,在此基础上,运用Piper三线图图示法和离子比例系数法,系统研究了地下水水化学的空间分布特征与演化规律。【结果】1由南而北,研究区地下水水化学特征呈环带状分布,主要从HCO_3·SO_4·Cl-Na·Mg·Ca、HCO_3·Cl-Mg·Na型向SO_4·Cl-Na、Cl-Na型演化转变,矿化度由小于1g/L增至10g/L以上。2溶滤作用、蒸发浓缩作用、阳离子交换作用是控制研究区地下水水化学演化的主要水化学作用,沿地下水径流方向,主要发生了石盐、石膏和长石的溶解反应、方解石和白云石的沉淀反应及Ca-Na阳离子交换反应。【结论】诺木洪河流域地下水水化学特征受水循环特征影响,戈壁滩与冲洪积平原区地下水水化学类型以HCO_3·Cl-Na·Mg为主,矿化度小于1g/L,为淡水;冲湖积平原区地下水水化学类型以Cl-Na为主,矿化度大于1g/L,为咸水甚至卤水。     

水化学分析方法在水电工程勘探中

水电工程有限的勘察及水文地质钻探仅能获取少量水文地质信息，而在工程勘察特别是平硐中，易取得出水点的水样，通过水化学分析可以获得更多的水文地质资料。通过对四川省自一里水电站平硐出水点水化学样的系列采集和测试，运用水化学成分离子比例分析法、灰色关联分析法和D、18O同位素分析等多种方法提取了平硐区水文地质信息，分析了山区平硐裂隙水的来源、补给高度及岩层渗透性等水文地质特征，探讨了水化学分析方法在分析水电工程水文地质条件中的应用。     

民勤绿洲地下水环境动态研究

根据民勤绿洲1999～2008年51眼地下水位观测井资料和2010年采集的30个地下水水样资料,利用传统统计学和地统计学分析方法对该地区新时期地下水位时空变化动态和地下水化学特性进行了研究。结果表明:民勤绿洲地下水位近10年来总体呈逐年下降的趋势,年均降幅达0.52m;在引黄民调工程、石羊河流域分水方案等政策措施的影响下,2005、2007和2008年地下水位降幅均呈现减小趋势,并在2007年首次出现0.01m的回升;坝区和泉山区地下水位年均降幅较湖区分别高0.23m和0.52m,下降速度明显快于湖区;整个绿洲区地下水平均矿化度为3.34g/L,沿地下水流动方向,地下水化学类型变化较大,由坝区和泉山区南部的SO42--HCO-3-Na+或SO42--HCO-3-Ca2+型淡水-微咸水逐渐变为湖区的SO2-4-C1--Na+-Mg2+咸水-苦咸水。     

流溪河水源林流域径流水化学含量及评价

对流溪河２７个水源林汇水区地下径流、５个河段、３个湖水中１２项元素检测，各检测区的水温、ｐＨ、ＤＯ、ＴＤＳ、ＢＯＤ５、Ｐｂ、Ｃｄ范围分别为１９．０～２２．５℃，６．３６～７．６５，８２％～９４％，７．６５～９５．６ｍｇ·Ｌ－１，０．２０～３．３０ｍｇ·Ｌ－１，０．０４～＜０．０００１ｍｇ·Ｌ－１，≤０．０００１ｍｇ·Ｌ－１；其中１７个集水区径流的氨氮、硝态氮、Ｃｌ－、ＳＯ４２－均值分别为０．４８４ｍｇ·Ｌ－１，０．２９２ｍｇ·Ｌ－１，２．７９２ｍｇ·Ｌ－１，２．２６４ｍｇ·Ｌ－１，总磷在０．０１０８～０．１１４３ｍｇ·Ｌ－１之间．采用水质指标叠加统计及ＧＢ３８３８－８８评价，８４％的检测区径流为清洁优质水．８．５％的检测区径流为尚清洁水，检测区径流水质聚类结果也相吻合，水源林具有贮滤净化水质效应．     

内蒙古克旗地区四座水库的水化学和水生生物调查

报道１９９４年７月和９月对克旗四座水库进行水化学和水生生物调查的结果．１）库水盐度０．１２‰～０．１５‰；ＡＬＫ平均１．４３ｍｍｏｌ／Ｌ；Ｔ．Ｈ平均１．３７ｍｍｏｌ／Ｌ，水化学类型按阿列金分类法，响水水库属Ｃ型，其余三座均属碳酸盐类钙组Ｉ型水（Ｃ）．２）共见到４０属浮游植物和３１种浮游动物，底栖动物和鱼类种种类很少，浮游植物平均生物量１．７８～１２．４１ｍｇ／Ｌ，优势种为直链藻，小环藻，角星鼓藻，     

A novel approach to studying the effects of temperature on soil biogeochemistry using a thermal gradient bar

The temperature dependence of chemical reaction rates and microbial metabolism mean that temperature is a key factor regulating soil trace gas emissions and hydrochemistry. Here we evaluated a novel approach for studying the thermal response of soils, by examining the effects of temperature on gas emissions and hydrochemistry in (a) peat and (b) soil from a Sitka spruce plantation. A thermal gradient was applied along an aluminium bar, allowing soil to be incubated contemporaneously from 2 to 18 °C. The approach demonstrated clear differences in the biogeochemical responses of the two soil types to warming. The peat showed no significant emission of CH₄ at temperatures below 6 °C, while above 6 °C, a marked increase in the rate of release was apparent up to 15 °C (Q₁₀ = 2.5) with emissions being similar between 15 and 18 °C. Conversely, CH₄ emissions from the forest soil did not respond to warming. Nitrate availability in the peat decreased by 90% between 2 and 18 °C (P < 0.01), whereas concentrations in the forest soil did not respond. Sulphate availability in the peat decreased significantly with warming (60%, P < 0.01), while the forest soil showed the opposite response (a 30% increase, P < 0.01). Conventionally, thermal responses are studied by incubating individual soil samples at different temperatures, involving lengthy preparation and facilities to incubate samples at different temperatures simultaneously. Data collected on a given thermal response is usually limited and thus interpolated or extrapolated. The thermal gradient method overcomes these problems, is simple and flexible, and can be adapted for a wide range of sample types (not confined to soil). Such apparatus may prove useful in the optimization of management practices to mitigate the effects of climate change, as thermal responses will differ depending on land use and soil type.     

Manganese dynamics in a mangrove mud flat tidal creek in SE Brazil

This study investigated the behavior of soluble and particulate manganese, during tidal cycles in a mangrove tidal creek and adjacent mud flats in SE Brazil. We identify the major processes affecting manganese transport to mangroves. The results showed that manganese variability occurs both seasonally, and over the tidal cycle, in response to changing redox potentials. Tidal water flooding mud flats are enriched in manganese, originating from upward migration of reduced species and further adsorption onto suspended particles under oxic conditions. During the tidal cycle, particulate manganese concentrations are higher during flood periods, whilst dissolved concentrations are higher during ebb periods. Although quantitatively different, this pattern occurs both in winter and summer. The dynamics of manganese characterized in this study suggest that this metal may play a significant role as a conveyor of trace metals to mangrove ecosystems, as suggested by earlier studies.     

An integrative method to quantify contaminant fluxes in the groundwater of urban areas

Background, Aims, and Scope  Groundwater in urban areas is often contaminated and emission sources can be located close to groundwater wells. The delineation of contaminant plumes is difficult because of the various potential emission sources. Thus, detection, quantification and remediation of contaminated sites in a city need more integrative approaches. Methods  A method has been developed which allows quantification of mass fluxes of contaminants in groundwater between control planes. Budget zones along the flow path are defined to calculate a contaminant balance and to quantitatively reveal input areas. Concentrations and water budgets are used to calculate mass balances for each contaminant. The city of Darmstadt (Germany) was chosen to evaluate the method. Results  The groundwater monitoring wells (GMWs) upstream of the city showed anthropogenically superposed background values for all naturally occurring inorganic species. The contaminant concentrations increased in the city (probably influenced by road traffic, gas stations, leaking sewers, etc.). Downstream from the city, concentrations usually decreased. Organic compounds typical for urban environments, such as polycyclic aromatic hydrocarbons (PAH), locally exceeded drinking water regulations. In GMWs with high concentrations of organic contaminants in the city or downstream from industrial areas, a significant increase in Fe²⁺ and Mn²⁺ could be observed, in some cases coinciding with a decrease in NO₃, SO₄ and an increase in NH₄. Discussion  For typical urban contaminants, a positive budget was calculated in several zones, which shows that emissions from urban sources are reaching the groundwater. Negative budgets can be mainly explained with diving plumes and degradation. The input calculated from the individual budget zones is usually higher than the input estimated from urban emissions. Differences between the calculated and the estimated input can be explained with additional sources or (bio)degradation processes. Conclusions  It was confirmed that high concentrations of contaminants do not necessarily correlate with high fluxes. Integrative approaches can reveal areas of high contaminant mass input. The results obtained with the new method are plausible compared to the land use and the estimated urban input. The concentration pattern of Fe²⁺, Mn²⁺, SO₄ and NO₃ is partly due to natural processes, triggered by the degradation of organic matter and organic contaminants. Recommendations  Since this method includes mass balances and flux calculations, avoiding an overestimation of single point contaminant concentration, it is recommended to use this approach to quantify groundwater contamination in cities. Further research is focusing on the role of urban soils as natural reservoirs for the input of contaminants.     

三江平原典型湿地水化学性质研究

以三江平原湿地生态试验站为研究基地,选择典型采样地点,对湿地水、排水沟水、降水、保护区河流水样进行测试,分析水样中主要离子含量(HCO3-、Cl-、NO3-、SO42-、Ca2 、Mg2 、K 、Na )、重金属元素含量(Cu、Zn、Fe、Mn)和营养元素含量(N、P、K)及其有效性。研究湿地水化学的一般性质以及湿地排水后湿地水中化学元素的迁移特征。研究结果表明,湿地水化学类型一般为HCO3--Ca.Mg型和HCO3--Ca.Na型,重金属序列为Fe>Mn>Cu>Zn>Pb、Cr。排水中丧失大量的化学元素,这是湿地退化的原因之一。     

石羊河流域中下游浅层地下水水化学特征及其成因

为系统研究石羊河流域中下游浅层地下水水化学特征及主要离子来源,于2018年6-8月采集地下水水化学样品62组。综合运用数理统计、Gibbs图、离子比例关系和水文地球化学模拟等方法,分析了石羊河流域中下游浅层地下水的水文地球化学特征,探讨了水化学演化过程及主要离子来源。结果表明:研究区浅层地下水在水平方向上呈现明显的水化学分带,从中游至下游地下水水化学类型由SO4·HCO3-Na·Ca型过渡为SO4·Cl-Na·Mg型,TDS含量也随之升高,流域中游为TDS含量小于1g/L的淡水,至下游演化为TDS含量高于1g/L的微咸水和咸水。该区浅层地下水水化学组分主要受水岩作用和蒸发浓缩作用控制,Ca²⁺、Mg²⁺主要来源于硅酸盐岩和碳酸盐岩的溶解,碳酸盐岩以白云石风化溶解为主,部分水样点存在方解石的风化溶解,阳离子交换作用是影响研究区地下水化学组分的重要过程。模拟结果表明沿地下水流向,地下水离子组分浓度呈递增趋势,岩盐、白云石和石膏发生溶解,方解石沉淀;从中游到下游地下水中阳离子交换作用越来越强烈,且阳离子交换作用强于溶解沉淀作用。