河流活性物质入海通量:概念与方法

河流水体中呈溶解态和悬浮物结合态的元素活动性强,具有生态环境意义,查明其入海通量是当前生态地球化学评价的重要任务。通过总结前人的相关研究成果,确定了影响河流水体悬浮物的浓度及其矿物、化学组成的主要因素。从沿海经济带区域生态地球化学评价的实际需要出发,拟定了开展中国主要入海河流水溶态和悬浮物结合态元素入海通量调查的基本框架。     

中国东部主要入海河流As元素分布、来源及影响因素分析

为查明中国河流中As等重金属元素的分布规律,于2007—2008年分丰水期和枯水期对中国东部30余条入海河流水体、悬浮物统一进行采样分析。结果表明:东部河流中As元素溶解态含量均值为3.1μg/L,同世界河流相比,明显偏高;且频率分布直方图具有多个峰值,反映出明显的人为污染。利用富集系数的研究表明,悬浮物同样受到较明显的人为污染。As在河水中的迁移形式以溶解态为主,pH值和温度对As的迁移形式有明显影响。流域内岩石类型对河流中As含量影响显著,火山岩、火山碎屑岩类广泛分布的流域河水中As含量明显偏高,花岗岩及中、深变质岩广泛分布的流域河流中As含量则偏小。利用生活、工业污水作为As元素人为来源端元,对海河、黄河、长江、珠江等河流人为源进行了估算,分别为46.7%、18.7%、13.5%、8.3%。     

河流活性物质入海通量:初步成果

河流是陆地与海洋相互作用的重要纽带,查明陆地河流活性物质入海通量是当前生态地球化学评价的一项重要任务。文中选择了中国东部入海河流中主要的35条河流,分丰、枯水期系统采集了悬浮物、过滤水、底泥等样品,利用河流径流量参数,计算得到了各河流主要重金属及营养元素的年入海通量及陆地河流年入海总通量,确定了各元素水溶态及悬浮物态迁移入海量的比例,为陆海相互作用研究、浅海生态地球化学评价提供了重要依据。     

水位变化影响下的河水-地下水侧向交互带地球化学动态

为了解不同水位变化影响下的河水与地下水侧向交互带地球化学特征动态,以重庆市马鞍溪为研究对象,选取丰水期向枯水期过渡的10-12月为研究期,对河水、地下水及交互带的水位、水温、溶解氧（DO）、pH值、电导率（EC）进行监测,结合对水体主要离子浓度的分析。结果表明,随枯水期到来,侧向交互带水位发生较大变化,交互带与河水间的水位梯度缩小,河水入渗动力逐渐减弱。水位的变化及入渗水温的降低,使交互带微生物活动减弱,pH值上升且变幅减小,DO上升。在其影响下,交互带EC下降,变幅减小,交互带对NO₃-、SO₄2-的净化能力降低,对Mn、Zn等重金属固定能力增强。通过分析交互带地球化学特征的变化,可推断出随马鞍溪枯水期的到来,侧向交互带边界由距河岸30~50 cm移动至距河岸30 cm以内。     

海南岛主要河流水体中重金属元素迁移富集特征

河流体系中的重金属元素主要存在于悬浮颗粒物、溶解相和沉积物三部分中.选择海南岛12条主要河流,分别在丰水期和枯水期采集过滤水、悬浮物及水系沉积物样品,分析重金属元素在过滤水、悬浮物及水系沉积物中的含量特征,总结水体中重金属元素的地球化学迁移方式及富集特征,查明重金属元素迁移富集的主要影响因素.     

鄱阳湖流域水化学特征及影响因素分析

在地球表生系统中,化学风化作用强烈改变着岩石、水体、土壤和大气成分,是元素地球化学循环的最主要驱动力。河水溶解物质主要来源于流域内岩石化学风化,同时受到降水、人类活动的影响。文中通过对鄱阳湖流域河水样品的采集和化学成分分析,结合流域地质背景,研究了河水化学成分特征及其影响因素。结果显示,与20世纪80年代相比,本区河水Cl-、SO24-所占比例显著增高,有逐渐酸化趋势;与世界上其他主要河流相比较,该区Ca2+/Na+、Mg2+/Na+、HCO3-/Na+等比值偏低,反映了较强的蒸发岩溶解及人类活动影响特征。该区河水离子特征主要由岩石风化所控制,降水对该区河水溶解物质贡献率为10.3%,农业生产活动对鄱阳湖水溶解物质贡献率为4.9%,矿山活动对饶河丰水期、枯水期离子总量贡献率分别为8.9%、14.6%。     

洮河流域水化学特征及其时空变化研究

以洮河流域河水为研究对象,通过对2018年每隔1月洮河干流及支流博拉河和广通河采样点的河水进行水化学研究,揭示了洮河流域河水的水化学组成,探讨了其水化学性质时空变化。结果表明：洮河流域水质偏碱性,干流上游pH值小于下游,并在枯水期都比丰水期为大;矿化度呈枯水期比丰水期小,河水属于中等矿化度水和适度硬水;总硬度、电导率呈枯水期比丰水期大;HCO₃^-、Ca²⁺、Na⁺、Cl^-、SO₄^2-、CO₃^2-含量呈枯水期比丰水期大;干流上游HCO₃^-、Ca²⁺、CO₃^2-含量大于下游,干流上游Mg²⁺、K⁺、Na⁺、Cl^-、SO₄^2-、MnO₄<...     

黄河、淮河及长江流域地表水环境中锶的地球化学特征

锶是自然界广泛分布的微量元素,在生物、化学及地质过程中不易发生分馏作用,具有很好的地球化学指示意义.尤其在水文地球化学研究中,由于不同岩石锶含量不同,大气降水降落在地面后流经不同岩石,致使地表水中锶元素浓度和同位素比值不同.因此,通过研究河水中锶元素的地球化学行为,可以帮助我们探究河流集水处矿物化学风化速率、气候变化、上地壳化学特征、同位素组成以及陆地-河流-海洋之间的营养元素循环等等[1,2].     

江苏灌河入海口附近重金属元素环境地球化学质量分析

以往对灌河口附近海域进行地球化学调查发现,海底沉积物及海水质量总体良好,但局部沉积物中Cr含量高于一类标准,Cu、As、Pb、Hg等其他重金属元素含量也明显高于其他地区,个别重金属元素已接近一类标准最高限,存在潜在生态风险。为进一步了解其与人类活动是否有关,对灌河靠近入海口40 km长的河水进行了地球化学调查,发现灌河河水中Hg、Cu、Pb等重金属元素存在一定程度的超标现象。结合其他证据认为,人类活动不仅对灌河下游河水质量产生了负面影响,还对入海口附近的海域环境质量产生了潜在威胁。借鉴内梅罗综合指数评价思路对灌河下游及入海口的重金属元素环境质量进行评价,并对如何降低、消除生态风险提出了若干建议。     

中国东部主要河流稀土元素地球化学特征

在2007年底至2008年初的枯水期间,系统采集了中国东部流域面积和径流量较大的33条河流沉积物、悬浮颗粒物和水样,采用等离子质谱法、X荧光光谱法等方法测定了14种稀土元素含量以及常量组分和水体pH值等理化指标。研究发现中国河流稀土元素浓度总体高于世界均值,且南方河流沉积物、悬浮物稀土元素含量高于北方河流,南方河流悬浮物态中稀土、重稀土呈现一定程度的相对富集,与我国上地壳稀土丰度和稀土矿产种类的南北分异相吻合。展示了以中国东部泥质岩稀土元素丰度标准化后的稀土配分模式及Ce、Eu异常特征,发现河流沉积物的中、重稀土元素相对富集,悬浮物轻稀土相对富集,溶解相重稀土富集的特征;北方河流溶解相稀土元素浓度明显大于南方河流,且除小清河外,溶解相Eu不同于沉积物与悬浮物而呈强烈的正异常,主要与河水理化性质影响下的稀土分异有关。研究发现小清河等少数河流沉积物中稀土元素为异常高值,经Al标准化处理、计算拟合剩余值后,认为小清河等河流稀土元素已受人为污染的影响。     

水沙动态图法分析中国主要江河水沙变化

利用《中国河流泥沙公报》数据,采用水沙动态图方法并按平衡水沙比相对应,分析中国主要河流2006年前实测水沙的变化。根据河流下游站历年水沙变化趋势,将中国主要河流大致分为4类:水量不变沙量降低、水量和沙量均降低、水量和沙量同步略降低、几近断流断沙。按地域看,中国淮河及其以南大多数河流年径流量无明显改变,而年沙量呈明显下降趋势;淮河以北地区河流水沙量均呈明显下降趋势,特别是黄河年径流量的近10年平均值仅为多年平均值的1/3,输沙量10年平均值仅为多年平均值的1/4,而海河水系的河流下游几乎是断流断沙。总体上,中国大多数河流的沙量明显下降。大多数河流入海水沙量的明显降低主要是人类活动造成的,淮河及其以南河流沙量的降低多与水库兴建、河道采砂和水土保持工程等有关;北方河流水沙量的降低主要是引水量的大幅增加、水库建设及其运行方式的改变以及水土保持工程的发挥效益等造成的。分析也表明,利用水沙动态图法分析河流的水沙长期变化具有一定的优越性。     

Dissolved trace elements in river water: spatial distribution and the influencing factor, a study for the Pearl River Delta Economic Zone, China

Twenty-nine water samples were collected from different river channels of the Pearl River Delta Economic Zone, China. An inductively coupled plasma-mass spectromonitor (ICP-MS) was used to measure concentrations of the trace elements in these samples. The results suggest that the average concentrations of rare earth elements in river water show an increasing trend from the West River, the North River, the rivers of the Pearl River Delta, and the Shenzhen River to the East River. Relatively high concentrations of heavy metals appear in the East River, the rivers of the Pearl River Delta and the Shenzhen River, while the West River and the North River have relatively low heavy metal concentrations. Trace element concentrations in samples collected near urban or industrial areas are much higher than those of samples collected from distant areas, away from urban and industrial areas. After natural conditions, human activities have significant influence on the trace element concentrations in river water. This trace element concentration’s spatial distribution in the river water from the Pearl River Delta Economic Zone is actually an integrated effect of natural conditions and human activity.     

Trace element chemistry of major rivers in Orissa State, India

 Geochemical analyses of surface waters from rivers flowing through Orissa State, India, indicated that trace element concentrations were extremely variable and consistently higher than world river average. The Brahmani River was the most solute-rich river studied, followed by the Baitarani and Mahanadi Rivers. Although all three rivers drain similar geology, the Brahmani River catchment is heavily industrialized, and water samples collected upstream and downstream from industries indicated that anthropogenic activity directly influenced its chemical composition. Samples collected from several towns, in all three river systems, did not invariably show similar patterns, with various elements having higher dissolved concentrations upstream. Because the concentration of total solids increased downstream, this implied that some components of the sewage had effectively sequestered available elements from solution and converted them to particulate material. Although the impact of pollution is clearly recognizable in water samples collected in proximity to the anthropogenic source, there are only slight elemental accumulations in the lower reaches of the Mahanadi River, with no accumulation in the Brahmani River. Apparently for these large rivers, discharged effluent becomes rapidly diluted, while complexation and sedimentation further removes trace elements from the water column. However, in the less voluminous Baitarani River, elementar enrichment near the river's mouth suggests that in this secondary river, where dilution effects are less, the concerns over regional water quality may be more prevalent. Received: 1 April 1995 · Accepted: 30 August 1995     

Seasonal variability of element fluxes in two Central Siberian rivers draining high latitude permafrost dominated areas

In order to constrain the origin and fluxes of elements carried by rivers of high latitude permafrost-dominated areas, major and trace element concentrations as well as Sr and U isotopic ratios were analyzed in the dissolved load of two Siberian rivers (Kochechum and Nizhnyaya Tunguska) regularly sampled over two hydrological cycles (2005-2007). Large water volumes of both rivers were also collected in spring 2008 in order to perform size separation through dialysis experiments. This study was completed by spatial sampling of the Kochechum watershed carried out during summer and by a detailed analysis of the main hydrological compartments of a small watershed. From element concentration variations along the hydrological cycle, different periods can be marked out, matching hydrological periods. During winter baseflow period (October to May) there is a concentration increase for major soluble cations and anions by an order of magnitude. The spring flood period (end of May-beginning of June) is marked by a sharp concentration decrease for soluble elements whereas dissolved organic carbon and insoluble element concentrations strongly increase.When the spring flood discharge occurs, the significant increase of aluminum and iron concentrations is related to the presence of organo-mineral colloids that mobilize insoluble elements. The study of colloidal REE reveals the occurrence of two colloid sources successively involved over time: spring colloids mainly originate from the uppermost organic-rich part of soils whereas summer colloids rather come from the deep mineral horizons. Furthermore, U and Sr isotopic ratios together with soluble cation budgets in the Kochechum river impose for soluble elements the existence of three distinct fluxes over the year: (a) at the spring flood a surface flux coming from the leaching of shallow organic soil levels and containing a significant colloidal component (b) a subsurface flux predominant during summer and fall mainly controlled by water-rock interactions within mineral soils and (c) a deep groundwater flux predominant during winter which enters large rivers through unfrozen permafrost-paths. Detailed study of the Kochechum watershed suggests that the contribution of this deep flux strongly depends on the depth and continuous nature of the permafrost.     

珠江三角洲经济区河水中微量元素的空间分布

在珠江三角洲经济区采集了29个河水样品,利用高分辨率仪器ICP MS测量了河水中微量元素的含量。结果表明,河水中稀土元素的平均含量按西江、北江、珠三角河、深圳河、东江的顺序呈增加趋势;珠三角河及深圳河具有较高重金属含量,西江和北江中重金属含量相对较低,东江居中。经分析发现,珠江三角洲经济区河水中微量元素的空间分布特征是自然条件和人类活动共同作用的结果;自然环境对稀土元素的空间分布起主要作用;人类活动是影响重金属分布特征不可忽视的重要因素。     

Sources and flux of trace elements in river water collected from the Lake Qinghai catchment,NE Tibetan Plateau

River waters play a significant role in supplying naturally- and anthropogenically-derived materials to Lake Qinghai, northeastern Tibetan Plateau. To define the sources and controlling processes for river water chemistry within the Lake Qinghai catchment, high precision ICP-MS trace element concentrations were measured in water samples collected from the Buha River weekly in 2007, and from other major rivers in the post-monsoon (late October 2006) and monsoon (late July 2007) seasons. The distributions of trace elements vary in time and space with distinct seasonal patterns. The primary flux in the Buha River is higher TDS and dissolved Al, B, Cr, Li, Mo, Rb, Sr and U during springtime than those during other seasons and is attributed to the inputs derived from both rock weathering and atmospheric processes. Among these elements, the fluxes of dissolved Cr, B and Rb are strongly influenced by eolian dust input. The fluxes of dissolved Li, Mo, Sr and U are also influenced by weathering processes, reflecting the sensitivity of chemical weathering to monsoon conditions. The anthropogenic sources appear to be the dominant contribution to potentially harmful metals (Ni, Cu, Co, Zn and Pb), with high fluxes at onset of the main discharge pulses due, at least partially, to a runoff washout effect. For other major rivers, except for Ba, concentrations of trace elements are higher in the monsoon than in the post-monsoon season. A total of 38.5 ± 3.1 tons of potentially harmful elements are transported into the lake annually, despite human activities within the catchment being limited. Nearly all river water samples contain dissolved trace elements below the World Health Organization guidelines for drinking water, with the exception of As and B in the Daotang River water samples collected in late July probably mobilized from underlying lacustrine sediments.     

双台河口土壤中Mn、Zn和Rb的变化规律及其原因分析

选取辽宁盘锦双台河口滩涂翅碱蓬生长消亡区的20个土壤样本点,比较其与翅碱蓬生长繁茂区的11种微量元素含量,并对其变化量进行主成分分析,得出双台河口滩涂土壤中含量变化显著的微量元素为Mn、Zn和Rb。通过这3种微量元素含量变化曲线图,可以看出其含量变化趋势大体上是减少的,且距离拦海大坝越近,含量越高,距离拦海大坝越远,含量越低。研究区河口底泥中Mn、Zn和Rb的含量分别占研究区滩涂土壤中的47.6%、64.3%和78.5%,表明了研究区滩涂土壤中3种元素主要是由河口地区的沉积物带来的。河口地区水中的沉积物主要由两部分组成:一部分是由河水携带的泥沙颗粒直接在河口地区沉积形成;另一部分是由河水携带的大量胶体,在入海口处产生胶凝作用形成。     

Trace element distribution in waters of the northern catchment area of Lake Linneret,northern Israel

Waters of the northern watershed of Lake Kineret, sampled during the period 1978–1983, were analyzed for their major and trace element contents. The trace element concentrations of the major water sources of the watershed (the Dan and Banias springs) represent background values. After emergence, the waters are subjected to human activity. In crossing the populated and cultivated Hula Basin in man-made canals, the major and trace element contents increase. In comparison to the trace element concentrations, those of the major elements have narrow ranges and small temporal fluctuations. Trace element concentrations varied by 3 orders of magnitude, and temporal variations were large but not neccessarily seasonal. Point sources of trace elements were urban effluents, fish pond wastes, and peat soil drainage. The trace element concentrations decrease in the waters of the last segment of the Jordan River. All measured trace elements were below the criteria levels established by regulatory agencies. Several, however, were of the same order of magnitude. Addition of wastes from enhanced recycling, and morphologic modification of the final course of the Jordan River could result in increase in the trace element concentrations in the water.     

Multi-element geochemistry of sediments from the Pearl River system,China

Sediment samples were taken along the West, North, and East rivers of the Pearl River system at 28 locations in 1998, and a total of 49 elements were determined by ICP–AES, ICP–MS and INAA. The probability features of the datasets were studied, and the average concentrations of these elements in sediments of the three rivers were calculated. Significant differences in element concentrations among the three rivers were observed and the results were confirmed by statistical tests including analysis of variance (ANOVA), Kruskal–Wallis test, and t-test. Spatial distribution maps of element concentrations were produced using a geographical information system (GIS). The immobile trace elements (such as Sc, Ti, V, Cr, Mn, Fe, Co, and Ni) are enriched in the West River where limestone dominates the rock types in the watershed. Because of the strong weathering, immobile trace elements are enriched and reside in secondary minerals of the weathering products. All three rivers have high concentrations of rare earth elements (REEs) because of strong weathering, but relatively higher concentrations of REEs are observed in sediments of the East River where granite dominates the rock type. Granite contains high concentrations of REEs and the sediments have inherited this feature from their bedrock. Alkaline element (Li, Na, K, Rb, and Cs) concentrations are elevated in sediments of the East River, these may reside in granitic primary minerals. Relatively high concentrations of alkaline earth elements (Mg, Ca, Sr, and Ba) are observed in the West River, inherited from the limestone bedrock. High Pb and Bi concentrations are found in the North River and are caused by Pb mineralization and the discharge of a smelter in the upper reaches of the river. However, statistical tests did not indicate a significant difference between Pb concentrations in the North River and the other two rivers, which suggests that statistical results should be carefully used and explained.