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1.
砷、锑是地热水中的典型有害组分,受地热水独特水化学条件影响,常呈现与其他类型天然水体相异的形态分布特征。本文以西藏阿里的朗久、曲色涌巴、门士、莫落江等地热区为研究区,分析了含硫化物地热水中砷、锑在竞争巯基化过程影响下的形态分布特征。受富砷、锑岩浆流体输入或高温条件下热储围岩加强淋滤的影响,上述地热区排泄的地热水中砷、锑浓度范围分别可达5 833～20 750μg/L和579～2 129μg/L。地热水中砷以亚砷酸盐和砷酸盐为主要存在形态,但同时存在占总砷百分比在0.1%～55.1%之间的硫代砷酸盐;与砷的情况不同,地热水中锑检测出的形态均为亚锑酸盐和/或锑酸盐,所有样品中均未检出硫代锑酸盐。考虑到相当一部分地热水样品的S/Sb摩尔比在理论上满足硫代锑酸盐的形成条件,且所有样品中砷的富集程度均不同程度高于锑,我们认为地热水中锑的含氧络阴离子的巯基化过程受到了共存砷的强烈抑制。在硫化物相对于砷、锑总量并不充分盈余的情况下,砷的竞争巯基化是控制地热水中硫代锑酸盐形成的最重要因素。本工作及其研究结果有助于深入理解西藏地热水环境中砷、锑的环境地球化学行为。 相似文献
2.
《地质科技情报》2021,40(2)
硫代砷酸盐作为富硫地下水中砷的重要赋存形态,在其迁移转化过程中起着十分重要的作用,但现有硫代砷酸盐的标准合成方法流程复杂、操作繁琐,限制了对地下水中硫代砷酸盐赋存规律的研究。为此,首先改进了硫代砷酸盐标准物质的合成方法,采用操作简便的水热法合成了硫代砷化合物标准物质,建立了基于HPLC-ICPMS的硫代砷化合物分析方法,该方法检出限为0.01μg/L;探讨了不同保存条件对硫代砷化合物稳定性的影响,发现干冰速冻-20℃是地下水硫代砷酸盐样品的最佳保存条件。应用上述方法对大同盆地地下水中的硫代砷酸盐进行了取样分析,结果表明40%的水样中均检出硫代砷酸盐,最高质量浓度可达209.90μg/L;弱碱性还原条件有利于硫代砷酸盐的赋存,且硫化物质量浓度对硫代砷酸盐的生成有重要控制作用。对地下水中硫代砷酸盐的深入研究有助于揭示富硫地下水中砷的迁移转化规律,丰富和完善高砷地下水成因理论。 相似文献
3.
西藏搭格架高温热泉是我国大陆少有的大型间歇性喷泉,砷元素作为对人类威胁极大的环境问题普遍存在于热泉之中,搭格架高温热泉中砷元素质量浓度最高已达到了9.75 mg/L,其对地表水和浅层地下水的污染不容忽视。硫代砷是富含硫化物热泉中砷的存在形态之一,鉴于国内相关研究较少,本文对西藏搭格架地热区的热泉样品进行了水化学分析,并利用水文地球化学模拟软件PHREEQC开展了对热泉中砷元素存在形态的地球化学模拟。结果表明：西藏搭格架热泉中砷元素的存在形态有亚砷酸盐、砷酸盐和硫代砷,其中亚砷酸盐与砷酸盐是砷的主要存在形态,且在pH影响下两者之间存在相互转化关系;各种硫代砷按质量浓度由高至低依次为一硫代砷酸盐、三硫代砷酸盐、二硫代砷酸盐、一硫代亚砷酸盐、四硫代砷酸盐;硫代砷形态占总砷浓度比例主要受热泉中硫化物质量浓度、Eh（氧化还原电位）和pH等因素的控制,在硫化物质量浓度总体偏低的情况下,硫化物质量浓度的上升可促进其他形态的砷向硫代砷形态转化,强还原性环境有利于硫代砷形态的存在;此外,在中性环境下,硫代砷占总砷浓度比例随pH上升亦有上升趋势。 相似文献
4.
地热水中的砷含量常远超过其他类型天然水体,其形态分析具有重要环境地球化学意义;甲基硫代砷酸盐在特定水环境条件下可能成为砷的一种不可忽视的形态,但其环境地球化学研究几为空白.本研究合成了甲基硫代砷酸盐标准,建立了可同时定量测试天然水中多种甲基硫代砷酸盐（包括一甲基一硫代砷酸盐、一甲基二硫代砷酸盐、一甲基三硫代砷酸盐、二甲基一硫代砷酸盐、二甲基二硫代砷酸盐）及砷的其他常见形态的离子色谱-电感耦合等离子体质谱联用系统（IC-ICP-MS）及其方法,并分析了典型地热水样品中砷的形态分布,可为今后不同类型水环境中甲基硫代砷酸盐的地球化学研究奠定分析方法基础. 相似文献
5.
以我国大陆范围内典型的岩浆热源型水热系统——云南腾冲热海为研究区,在国内首次对热泉中硫代砷化物含量及其地球化学成因进行了分析.研究采用的在野外对富硫化物水样进行快速冷冻处理、而后在实验室进行砷的形态分离和测试的方法明显优于当前通用的水样砷含量及其形态分析的预处理和测试方法.主要原因为后者在采样现场对水样的酸化处理可使样品中三硫代砷酸盐以非定形态硫砷化合物的形式沉淀,且用常规阴离子交换柱在野外无法实现硫代砷酸盐的完全回收及其与砷酸盐的分离.受岩浆流体输入和热储内高温条件下强烈流体-岩石相互作用的控制,热海水热系统排泄的中性-偏碱性热泉中富集硫化物和砷,为热泉中硫代砷化物的形成提供了必要条件.热海热泉中检出的硫代砷化物包括一硫代砷酸盐、二硫代砷酸盐和三硫代砷酸盐,在总砷中所占比例最高分别可达26.7%、43.3%和33.7%.热海地热田的2个子区(硫磺塘和澡塘河) 的热泉沿不同断裂带出露,地热水升流过程中经历的冷却方式也不同,使硫磺塘热泉具有相对较高的总硫化物含量和总砷含量,并导致其中各类硫代砷酸盐具有更高的含量范围. 相似文献
6.
天然水环境中地质成因砷的存在是世界范围内对人类威胁极大的环境问题之一.在高温富硫化物地热水中,硫代砷化物是砷的主要存在形态之一.在国内尚无硫代砷化物定量检测方法的背景下,以云南腾冲地热带的热海水热区为典型研究区,基于不同类型硫代砷化物的最新化学热力学数据wateq4f.dat,利用水文地球化学模拟软件PHREEQC开展了不同类型热泉中砷的存在形态的地球化学模拟.结果表明,热海热泉中砷的主要形态是硫代砷酸盐,砷酸盐和亚砷酸盐次之,硫代亚砷酸盐则含量极低;在各类硫代砷酸盐中,按平均百分含量降序依次为:一硫代砷酸盐→三硫代砷酸盐→四硫代砷酸盐→二硫代砷酸盐.pH、Eh和总硫化物含量是热泉中砷的形态分布的控制性因素.在酸性条件下,砷以硫代砷酸盐和亚砷酸盐为主要存在形式;而在中性/偏碱性条件下,砷的形态则以硫代砷酸盐为主,砷酸盐次之.偏还原环境和高硫化物含量是硫代砷化物、特别是三硫代砷酸盐和四硫代砷酸盐稳定存在的有利条件. 相似文献
7.
地热水中的硫化物(H_2S、HS~-和S~(2-))通常受到硫酸根、亚硫酸根、硫代硫酸根等硫元素的共存干扰,并且硫化物具有热、光、氧不稳定性,在水样保存、前处理、标准溶液配制等环节影响着测试的准确度和精密度。本文在现场采集的地热水水样中加入乙酸锌及氢氧化钠,使硫化物形成硫化锌沉淀而与溶液分离,将此沉淀溶于双氧水和逆王水,使低价态的S2-氧化成稳定的SO_4~(2-),选择易于纯化且性质稳定的硫酸钠配制硫标准储备液,以182.624 nm谱线作为硫元素分析谱线,应用电感耦合等离子体发射光谱法测定出地热水样中的硫化物含量。硫的浓度在0.1~100 mg/L范围内与其发射强度呈线性(相关系数为0.9994);方法检出限为0.009 mg/L,相对标准偏差(n=11)低于1.80%,实际水样中硫化物的加标回收率介于99.0%~103.0%。与前人相关测试方法相比,本方法的技术指标具有优势。 相似文献
8.
9.
锑为典型有害元素,地热成因锑是天然水环境中溶解态锑的重要来源,富锑热泉排泄的负面环境效应不容忽视.本文在藏南和滇西选择典型地热区,分析了热泉中锑的形态分布及其地球化学成因.总体上,研究区排泄的地热水具有远高于天然水环境背景值的锑含量,最高可达2 128.7μg/L.水文地球化学计算表明热泉中锑的主要存在形态为锑酸盐和亚锑酸盐,但部分热泉样品中硫代锑占总锑百分比可高达35%.硫化物浓度、S（-Ⅱ）/Sb摩尔比,以及砷锑之间的竞争巯基化作用是影响热泉中硫代锑含量的关键因素.在本研究所涉及地热系统中,西藏玛旁雍错曲色涌巴、门士、莫落江为岩浆热源型地热系统,其地热水中锑源自高温条件下热储围岩淋滤和作为热源的岩浆房所释出流体的输入,西藏曲卓木、朗久与云南邦腊掌则属于非岩浆热源型地热系统,其热泉中的锑主要来源于地热水-围岩矿物相互作用. 相似文献
10.
《吉林大学学报(地球科学版)》2015,(Z1)
<正>水体中砷的迁移转化行为受其赋存形态影响。一般有氧水体和缺氧水体中,常见的无机砷形态为砷酸根(HAs O42-,H2As O4-和As O43-)或亚砷酸(H3As O3);在一些含硫的缺氧水体中,元素硫参与砷的地球化学循环,与之形成含砷硫化物沉淀或者可溶的硫代砷(thioarsenic species)。硫代砷形态十分复杂,按照砷的价态可分为硫代As(V)(thioarsenate,H3AsVOx S4-x,x=0~3)和硫代As(III)(thioarsenite,H3AsIIIOx S3-x,x 相似文献
11.
Thermodynamic Modeling of Thioarsenic Species Distribution in High As Groundwater in Hetao Plain* 总被引：1，自引：0，他引：1
Thioarsenic has gained increasing attention as a newly identified arsenic species. This paper selected Hetao Plain as the study area. Based on the field survey data and the thermodynamic reaction equation, the distribution characteristics of thioarsenic speciation in high-arsenic groundwater were simulated and analyzed. The results show that the major of arsenic speciation is arsenite, followed by thioarsenate and arsenate, and thethioarsenite concentrations are extremely low. Among them, monothioarsenate and trithioarsenate are the predominant thioarsnate species, with monothioarsenite being the dominant thioarsenite. In the buried depth of the range of 5~40 m, the content of various arsenic species does not change significantly with increasing depth. In the range of 40~80 m buried depth, the content of arsenite decreases with the increase of depth, and the content of thioarsenite increases with depth. Sulfide concentration has a significant effect on the distribution of arsenic species. When the concentration of sulfide is less than 5 μg/L, the various arsenic species do not change regularly with the increase of sulfide concentration. When the sulfide concentration is more than 5 μg/L, the content of arsenite and arsenate decreases with the increase of sulfide concentration, and the content of thioarsenate and thioarsenite tends to increase, and mutual transformation happens between different thioarsenite and thioarsenate species. 相似文献
12.
Geochemical process regulating groundwater quality in a coastal region with complex contamination sources: Barka,Sultanate of Oman 总被引：4，自引：2，他引：2
An investigation was carried out to evaluate the geochemical processes regulating groundwater quality in a coastal region,
Barka, Sultanate of Oman. The rapid urban developments in Barka cause depletion of groundwater quantity and deterioration
of quality through excessive consumption and influx of pollutants from natural and anthropogenic activities. In this study,
111 groundwater samples were collected from 79 wells and analysed for pH, EC, DO, temperature, major ions, silica and nutrients.
In Barka, water chemistry shows large variation in major ion concentrations and in electrical conductivity, and implies the
influence of distinguished contamination sources and hydrogeochemical processes. The groundwater chemistry in Barka is principally
regulated by saline sources, reverse ion exchange, anthropogenic pollutants and mineral dissolution/precipitation reactions.
Due to ubiquitous pollutants and processes, groundwater samples were classified into two groups based on electrical conductivity.
In group1, water chemistry is greatly influenced by mineral dissolution/precipitation process and lateral recharge from upstream
region (Jabal Al-Akdar and Nakhal mountains). In group 2, the water chemistry is affected by saline water intrusion, sea spray,
reverse ion exchange and anthropogenic pollutants. Besides, high nitrate concentrations, especially in group 2 samples, firm
evidence for impact of anthropogenic activities on groundwater quality, and nitrate can be originated by the effluents recharge
from surface contamination sources. Ionic ratios such as SO4/Cl, alkalinity/Cl and total cation/Cl indicate that effluents recharged from septic tank, waste dumping sites and irrigation
return flow induce dissolution of carbonate minerals, and enhances solute load in groundwater. The chemical constituents originating
from saline water sources, reverse ion exchange and mineral dissolution are successfully differentiated using ionic delta,
the difference between the actual concentration of each constituent and its theoretical concentration for a freshwater–seawater
mix calculated from the chloride concentration of the sample, and proved that this approach is a promising tool to identify
and differentiate the geochemical processes in coastal region. Hence, both regular geochemical methods and ionic delta ensured
that groundwater quality in Barka is impaired by natural and human activities. 相似文献
13.
Evangelos P. Tziritis 《Central European Journal of Geosciences》2009,1(2):219-226
The Kopaida plain is a cultivated region of Eastern Greece, with specific characteristics related to the paleogeographic evolution and the changes in land use of the area. This study examines the geochemical conditions of the groundwater and soil, and the correlations between them. 70 samples (50 samples of groundwater and 20 samples of soil) were collected in order to asses the geochemical status and the major natural and manmade affecting processes in the region. Extended chemical analyses were carried out including the assessment of 28 parameters for groundwater and 13 for soil samples. The results revealed that groundwater geochemistry is influenced primary by natural processes such as the geological background, and secondary by manmade impact mainly deriving from the extended use of Nitrogen-fertilizers and the over-exploitation of boreholes. Soil geochemistry is influenced exclusively by natural processes, such as weathering of the prevailing geological formations. Chemical analyses and the statistical processing of data revealed that the major factor for the geochemical status of soils is the weathering of the karstic substrate, as well as the existing lateritic horizons and a weak sulfide mineralization. 相似文献
14.
PHREEQC在地下水溶质反应-运移模拟中的应用 总被引：7，自引：2，他引：7
由于地下水污染的加剧,对地下水中污染物运移规律的研究日益受到重视。地下水中的溶质在运移过程中伴随着溶质组分间的化学反应,因此需要建立地下水溶质运移与化学反应的耦合模型。PHREEQC是近年来发展起来的描述局部平衡反应、动态生物化学反应的水文地球化学模拟软件。本文利用该模拟软件对一维地下水流动过程中溶质离子交换反应和动态氧化还原反应进行了模拟。结果表明,PHREEQC能够成功地进行溶质运移情况下复杂水化学反应模拟,但对于复杂地下水流和溶质运动的情况,有必要耦合其它的地下水流动和溶质运移软件来共同完成。 相似文献
15.
Analysis and hydrogeochemical modeling of hydrocarbonate groundwater, including its buffering geochemical properties, have
demonstrated that this water has undergone a geochemical transformation almost throughout the whole of one industrial region.
It is known that hydrocarbonate groundwater possesses a high protective natural geochemical potential, supporting neutralization
of acid atmospheric precipitation. Natural hydrocarbonate water undergoes three stages of anthropogenic transformation caused
by acid atmospheric precipitation over more than 50 years. The first stage is transformation of neutral hydrocarbonate water
into alkaline water, accompanied by calcite precipitation and sodium carbonate dissolution from the unsaturated zone. The
second stage is transformation of alkaline water into neutral hydrocarbonate water; the hydrocarbonate content, being less
than the lower limit for background concentrations, showed reduced water buffering properties or protective potential relative
to acid precipitation. The third stage is transformation of neutral hydrocarbonate water into acidic water, with a complete
loss of protective geochemical potential.
This unfavorable ecological situation with natural geochemically hydrocarbonate groundwater shows that natural groundwater
less protected from the impact of acid atmospheric precipitation is in a worse ecological condition, which is confirmed by
observations in northern and Western Europe and other regions of the world.
Received: 30 October 1997 · Accepted: 23 March 1998 相似文献
16.
I. I. Silin 《Lithology and Mineral Resources》2008,43(3):220-227
Pollution of potable water with natural elements is an important issue for many towns of central Russia. Study of the chemical composition and hydrodynamics of groundwaters made it possible to establish some regularity in the influence of the anthropogenic load and exploitation regime of water intake (hereafter, intake) on their quality. It is shown that the quantitative prognosis of pollution of water wells should be based on the complex study of geochemical, hydrodynamic, and economic conditions of water consumption. Solution of the problem concerning the quality of groundwater within natural-technogenic hydrogeochemical anomalies requires an integrated strategy of measures aimed at adaptation of the water consumption to limits of natural stability in the water basin and to reduction of the emission of technogenic toxic substances and greenhouse gases. It is recommended to carry out complex geochemical studies of the aquifer in order to predict the possible groundwater pollution by natural pollutants. The study is based on the results of analysis of 5000 samples carried out at the Chemical-Analytical Center of the Taifun Scientific-Industrial Enterprise of the Russian Hydrometeorological Center and the Vodokanal Small Enterprise (Obninsk). 相似文献
17.
H. Seshadri R. Kaviyarasan P. Sasidhar V. Balasubramaniyan 《Journal of the Geological Society of India》2013,82(5):535-544
Geochemical signatures of groundwater in Kalpakkam plant site were used to identify the geochemistry of the unconfined coastal aquifer. Ground water samples collected from 14 borewells around the study area were studied for four different seasons viz. Summer, South-west monsoon, North-east monsoon and Post-monsoon to identify the major geochemical processes activated in the study area. Data obtained through chemical analyses of groundwater samples were used for graphical plots and geochemical calculations. Piper, Chloro alkaline indices and Chadda’s diagram were determined for geochemical classification of the groundwaters. Identified geochemical processes were verified and quantified using hydrogeochemical aqueous speciation model, PHREEQC to find out the Saturation Indices (SI) of the possible minerals of the study area. It was observed that majority of the bore well samples were under saturated with respect to minerals such as Gypsum, Aragonite and oversaturated with respect to dolomite and calcite. Parameters such as ion exchange and reverse ion exchange, saline water incursion were observed due to the presence of saline water bodies in addition to dissolution of minerals. 相似文献