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1.
贵阳地表水—地下水的硫和氯同位素组成特征及其污染物示踪意义 总被引：5，自引：0，他引：5
喀斯特地表水和地下水的交换活跃,地下水系统容易受到地表污染物的污染。为了解喀斯特城市地表水—地下水系统污染特征和污染物质来源,对贵阳市地表水、地下水、雨水和城市排污污水的硫同位素和氯同位素组成变化进行了研究。贵阳市不同类型水体的δ37Cl值在-4.07‰～+2.03‰之间变化,δ34SSO4值变化为-20.4‰～+20.9‰。大气输入物质和城市排污污水的δ37Cl、δ34S及Cl-/SO42-比值与地表水和地下水的不同,稳定硫和氯同位素的结合研究为示踪地下水污染物来源提供了有效研究手段。贵阳市地下水中的Cl-和SO42-至少有4种来源,人为活动通过城市排污和大气输入向地下水系统大量输入了硫酸盐和氯离子。 相似文献
2.
地下水中高氯酸盐来源的同位素示踪研究进展 总被引：1，自引：0，他引：1
高氯酸盐(ClO-4)是一种新型的持久性污染物,痕量的ClO-4即可危害人体的健康。中国地下水中ClO-4的污染防治研究迫在眉睫,污染来源解析是其首要解决的关键问题。现阶段的研究表明,ClO-4的氯(δ37 Cl、36 Cl/Cl)和氧(δ18 O、Δ17 O)多元同位素的综合信息为地下水中ClO-4来源及其迁移转化规律的示踪提供了一种重要的工具。ClO-4的氯、氧同位素的测试技术、分馏机理及其对地下水中ClO-4的溯源应用等方面取得了创新性的成果,为我国有效开展地下水中ClO-4来源的定性识别与定量评价研究提供了技术支撑和科学依据。然而,现有的研究成果具有明显的地域局限性,不同区域ClO-4来源的氯、氧同位素特征值的丰富与端元模型的完善,特别是人工合成的ClO-4来源的有效解析,具有重要的理论意义和应用价值。 相似文献
3.
氯元素广泛分布于地表水体和沉积物中,并在地表圈层之间进行迁移和转化等生物地球化学循环.氯元素有两种稳定同位素:35Cl和37Cl,其相对含量分别为35Cl=75.153%和37Cl=24.147%.氯离子在地表环境中通常没有价态变化,既不发生引起键能明显变化的氧化还原反应,也不明显参与生物作用,因此氯离子不会因元素迁移形态转变而改变同位素组成.但是,自然界中氯同位素37Cl和35Cl间存在较大的相对质量差,氯在蒸发结晶、离子扩散、渗透和对流混合等水体迁移过程中35Cl和37Cl的运移速度因其质量差而有所不同,致使氯同位素发生分馏[1].在蒸发沉积作用过程中,因37Cl相对35Cl有较大的键结合能,而优先进入固相(盐类沉积物)中.相对于其它轻稳定同位素(H、O、C)而言,稳定氯同位素的分馏并不明显,自然界中δ37Cl为-14‰～16‰,但大气圈、水圈和岩石圈的氯同位素组成大多集中在-2‰～2‰.近年来,氯同位素测定方法的改进大大提高了测试精度和准确度,使得氯同位素得以广泛应用于对蒸发盐、地下水体的演化、海水入侵、矿床形成过程中的成矿流体作用、氯代有机溶剂的分馏机理、人工合成与自然降解的有机物示踪等方面的研究[2～10]. 相似文献
4.
监测自然衰减(monitoring natural attenuation,MNA)技术是目前普遍认可的去除地下水中挥发性有机污染物(volatile organic compounds,VOCs)的技术。但受其修复周期长、监测费用昂贵等因素的影响,实地开展MNA技术修复污染场地具有一定的局限性。基于此,本研究运用多相流数值模拟手段识别了某石油污染场地内典型VOCs污染物(苯、甲苯、萘)在地下水中的自然衰减过程并评估了其自然衰减能力。结果表明:采用TMVOC所建立的多相流数值模拟模型能较好地预测和识别VOCs在地下水中的衰减规律;在研究区中,苯、甲苯和萘由于理化性质差异,在地下水中的污染羽分布特征不同,其自然衰减过程受挥发、吸附和生物降解作用的影响程度也不同;挥发和生物降解作用对VOCs自然衰减的影响程度均为苯>甲苯>萘,而吸附作用对VOCs自然衰减的影响程度为萘>甲苯>苯;在污染源被阻断的前提下,苯、甲苯和萘分别在泄漏发生7.0、6.5和6.0年后通过自然衰减达到理想去除效果。本文研究成果可以为水文地质条件类似的VOCs污染场地MNA修复方案的制定和修复效果评估提供理论支撑。 相似文献
5.
氮、氧同位素在地下水硝酸盐污染研究中的应用 总被引：8，自引：0，他引：8
硝酸盐是地下水中难以去除的稳定污染物之一,是地下水氮(N)污染的主要形式.不同氮来源的硝酸盐氮、氧(O)同位素组成不同,可利用N、O同位素并结合其他同位素技术示踪硝酸盐污染源,识别反硝化过程,对于有效控制污染源和评估地下水对硝酸盐污染的恢复自净能力有重要意义.本文介绍了N、O同位素技术在地下水硝酸盐污染源追踪和反硝化过程的识别方面的原理和应用以及目前发展状况. 相似文献
6.
以东北某油田石油污染场地多期地下水化学监测数据为基础,分析氯代烷烃自然生物降解中充当第一基质、电子受体、中间产物的水化学组分及相关地球化学参数在污染晕演化的不同时段、不同部位的变化趋势,了解氯代烷烃生物降解的地下水化学响应特征,并以此为依据对污染场地浅层地下水氯代烷烃生物降解程度进行定性评价。结果表明:2010年6月,事故发生约1年之际,在ZK1—ZK3—ZK6纵向剖面上生物降解过程中充当电子受体的水化学组分(SO42–)、第一基质(CH2Cl2、CHCl3)和代表地下水环境的主要理化指标(pH、Eh)从上游到下游均呈递增规律,而相关还原产物(Fe2+、Mn2+、HCO3–)则呈递减规律,这也表明天然微生物降解具有一定的滞后性。2010年6月氯代烷烃天然生物降解评价表明ZK1属微生物降解证据充足;ZK3观测井属微生物降解证据有限;ZK6观测井属微生物降解证据不足。而2011年5月,事故发生约2年之际,封堵污染源后随污染晕中心的向下游迁移,ZK3观测井中生物降解作用逐渐明显,在ZK3—ZK6纵向剖面上地下水化学指标呈现上述响应规律,而ZK1观测井诸多水化学指标经上游未污染地下水的补充更新,逐渐趋向污染前的背景值。 相似文献
7.
地下水污染源识别模型可利用有限的观测资料估计污染源位置、污染物泄露强度及其泄露过程,是制定地下水污染修复方案的依据。在阐明地下水污染源识别基本问题基础上,综述了污染源识别研究的两大类数学方法,一类为直接方法,包括反向追踪法和基于正则化的方法;另一类为间接方法,包括基于优化的方法和基于概率统计的方法。同时指出了当前污染源识别数学方法应用中存在的主要问题:地下水污染源识别问题的复杂性、地下水有机污染问题和模型求解效率的低下性。对土壤-地下水的联合管理、基于物联网的地下水污染监测、对非水相流体（Non-aqueous Phase Liquid,NAPL）类污染源识别以及基于图形处理器（GPU）的异构并行计算将是未来研究的重点方向。 相似文献
8.
抓有两个稳定同位素35Cl和37Cl，在自然界中的丰度分别为24.23％和75.77%。自然界中氯同位素的组成变化很小，氯同位素组成的表示方法一般用δ37C1值表示：37C1=[(37Cl/35C1)sample-1 (37Cl/35C1)Std]×1000 δ37C1在自然界的变化范围约为15‰(-8.0‰~+7.5‰)。由于海水中的氯同位素组成非常均一，Kaufman等（1984)调查发现世界大洋海水中氯同位素组成相同，因此建议采用标准海水（SMOC）作为氯同位素标准。氯同位素的分析方法主要包括气体同位素质谱法和热电离质谱法，目前的分析精度可达0.2‰。 对于大部分同位素而言，由扩散引起的同位素分馏主要与化学和生物过程有关。研究表明沉积物间隙水中造成氯同位素分馏的原因主要3个：①矿物在海水中沉淀的过程中优先富集37C1(Magenheim等，1994,1995);②扩散过程,35C1的扩散速度高于37C1(Desaulnier等，1986;Eggenkomip等，1994);③沉积物的离子隔膜过滤作用，当流体通过粘土矿物时，由于沉积物表层负电荷的排斥,35Cl受到的排斥作用大于37Cl，因此流体中会富集37C1，此机制被Campbell(1985）通过实验得到了证实。 氯是上地壳流体中主要的阴离子，在矿物岩石和矿床的形成过程中起着重要的作用，因此研究自然界中抓的分布和运移对于地球科学各个研究领域而言有着重要的意义。目前已对大气圈、水圈和岩石圈的氯同位素组成进行过分析，大气气溶液中δ37C1的变化范围为+0.42‰-2.53‰；河水中的δ37C1较高为+0.74‰-+2.85‰,盐湖卤水δ37C1则相对较低，为-2.06‰~+1.01‰，地下水中δ37C1变化范围较小为-0.50‰~+0.69‰；俯冲间隙水氯同位素组成最低，变化范围为-7.5‰~-2.2‰；新鲜的洋中脊玄武岩（ MORB）玻璃体中δ37C1的变化范围为+3.0‰~+7.2‰，去气地幔中δ37C1值为+4.7%；而富集地幔中δ37C1落在0.4‰~3.4‰之间；麻粒岩δ37C1的变化范围很小，其中大部分的岩石和矿物δ37C1都集中在-0.3‰~+0.11‰之间，平均值为-0.15‰，而角闪石和黑云母δ37C1分别为-1.12‰和+0.79‰;岩盐中δ37C1的变化范围为-0.6‰~+1.2‰。 氯同位素地球化学的研究工作在总体上仍处于起步阶段，但该方法在地球科学各个领域已经显示了极好的应用前景。氯同位素组成可以用于示踪板块俯冲和壳幔物质循环过程、热液成矿过程中成矿流体的起源和演化以及盐湖和岩石中卤水的起源和演化。 相似文献
9.
水资源中氯代烃污染物的去除方法 总被引：3，自引：0，他引：3
随着工业化的发展。氯代有机溶剂使用越来越广泛。并且难于去除。在20世纪90年代初期，人们就已认识到用Fe^0恢复污染的地下水的潜力。国外正在研究帮使用扔几种还原挥发性氯代烃的还原反应介质，尤其要提高的是双金属反应系统，反应速度快，而且脱Cl中国难解产物少，目前国也只停留在实验室研究阶段，个别做了地上反应器的验证实验，它的脱Cl机理、介质钝化和完全脱Cl问题还有待于进一步研究。 相似文献
10.
过去一直认为稳定氯同位素比值(~(37)Cl/~(35)Cl)几乎不变。80年代以来利用高精度质谱法成功地发现了自然界氯同位素分馏作用。单纯的溶解和对流迁移作用不能引起同位素组分变化,而扩散作用、离子渗透作用和对流混合作用却可导致同位素分馏。各地不同深度海水的氯同位素成分极为一致,故以标准平均海水氯(SMOC)作为对比标准。得克萨斯—路易斯安那海湾油田水的δ~(37)Cl大致为+0.5‰~-1.25‰,且与氯浓度大致呈正相关。热液成矿系统中,氯同位素可作为研究矿床成因的示踪剂,如美国田纳西州密西西比河谷型矿床(MVD)的δ~(37)Cl在+0.2‰~-1.1‰之间,几个斑岩铜矿床(PVD)的早期脉岩与晚期脉岩中不同δ~(37)Cl的存在,都表明在成矿过程中有不同氯源的参与。 相似文献
11.
12.
Soonyoung Yu Pyeong-Koo Lee Seong-Taek Yun Sang-Il Hwang Gitak Chae 《Environmental Earth Sciences》2017,76(9):338
Volatile organic compounds (VOCs) detected in stormwater were compared with VOCs present in emission sources, air, groundwater, and influent to sewage treatment plants in Seoul to understand their fate and transport in the urban hydrological system. Stormwater is a carrier of non-point source pollutants and contains VOCs from land surfaces and air. Samples of stormwater and influent to sewage treatment plants were collected and analyzed for 61 VOCs, while the VOCs in emission sources, air and groundwater were investigated through literature reviews for comparison. The results showed that the most frequently detected VOCs in stormwater were similar to those in air. However, the atmospheric concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX), and methyl tertiary-butyl ether (MTBE) were too low to explain their frequent detection and high concentrations in stormwater. As a result, land surfaces seem to be a primary source of these VOCs in stormwater. Comparison of the VOCs in stormwater and groundwater showed that toluene and MTBE were frequently detected in both media, but more often and at higher concentrations in stormwater. This finding indicates that stormwater recharge is a source of toluene and MTBE in groundwater. Regarding groundwater, land surfaces seem to be a primary source of toluene, while urban air is the primary source in the case of MTBE. Specifically, the MTBE values in air were sufficiently high to explain its levels in groundwater, which had continually increased and remained low afterward. Furthermore, the high ratios of TEX (toluene, ethylbenzene, and xylenes) to benzene and MTBE in stormwater indicated that TEX had additional sources other than vehicles, most likely hydrocarbon solvents. These solvents seem to be a primary source of TEX and other frequently detected VOCs in stormwater. However, trichloroethylene (TCE), tetrachloroethylene (PCE) and their dechlorination intermediates were far more frequently detected and at higher concentrations in groundwater than in stormwater. Additionally, their concentrations frequently exceeded the water-quality criteria. It seems that halogenated solvents had produced contamination plumes of these chlorinated VOCs in the Seoul aquifer. Based on VOCs detected in Seoul, stormwater was mixed with groundwater in combined sewers and flowed into sewage treatment plants. The results imply that organic solvents should be handled with extreme care to protect groundwater quality. 相似文献
13.
Contamination of groundwater by arsenic and other constituents in an industrial complex 总被引：2，自引：2，他引：0
This study examined the natural and anthropogenic pollution of groundwater at a national groundwater monitoring station (NGMS)
in a dyeing industry complex, Korea. The arsenic contamination of a shallow well at the NGMS was noticed, starting from 22 months
after the well installation. Possibilities of several mechanisms for As pollution of the groundwater were examined. The arsenical
pyrite oxidation as a source mechanism in the shallow aquifer may be disregarded because of deficiency of pyrite in the shallow
sediments, concomitant with depleted dissolved oxygen and very low levels of redox potentials of the As-polluted groundwater.
The effect of wastewater from the general industrial area through a covered sewer stream was also considered as a possible
source. Even though occurrence patterns of phenol and volatile organic hydrocarbons were very similar to those of the polluted
shallow groundwater, As was not detected in the wastewater. One of the most plausible sources of the arsenic pollution was
believed to be the reductive dissolution of Fe hydroxide. The As-polluted shallow groundwater had also very high levels of
pH, HCO3, COD and very low levels of DO and NO3, which support the possibility of As pollution by the reductive dissolution. Consequently, the shallow groundwater in and
around the NGMS has been polluted with various contaminants including As, phenol, chlorinated solvents, and petroleum hydrocarbons
through multiple sources of contamination, such as natural reductive dissolution, dyeing wastewater, industrial wastewater,
and municipal sewage. 相似文献
14.
Effects of land use on the spatial distribution of trace metals and volatile organic compounds in urban groundwater, Seoul, Korea 总被引：4，自引：0，他引：4
Seong-Sook Park Soon-Oh Kim Seong-Taek Yun Gi-Tak Chae Soon-Young Yu Seungki Kim Young Kim 《Environmental Geology》2005,48(8):1116-1131
To investigate the urban groundwater contamination by eight trace metals and 69 volatile organic compounds (VOCs) in relation
to land use in Seoul, a total of 57 groundwater samples collected from wells were examined using a non-parametric statistical
analysis. Land use was classified into five categories: less-developed, residential, agricultural, traffic, and industrial.
A comparison of analyzed data with US EPA and Korean standards for drinking water showed that some metals and VOCs exceeded
the standards in a few localities, such as Fe (N=5), Mn (N=6), Cu (N=1), TCE (N=6), PCE (N=8), 1,2-DCA (N=1), and 1,2-dichloropropane (N=1). Among the 69 investigated VOCs, 19 compounds such as some gasoline-related compounds (e.g., toluene) and chlorinated
compounds (e.g., chloroform, PCE, TCE) were detected in groundwater. Non-parametric statistical analysis showed that the concentrations
of most trace metals (Fe, Mn, As, Cr, Pb, Cd) and some VOCs (especially, TCE, PCE, chloroform; toluene, carbon tetrachloride,
bromodichloromethane, CFC113) are significantly higher in the industrial, residential, and traffic areas (P<0.05), indicating that anthropogenic contamination of urban groundwater by those chemicals is growing. Those chemicals can
be used as effective indicators of anthropogenic contamination of groundwater in urban areas and therefore a special attention
is warranted for a safe water supply in those areas. The results of this study suggest that urban groundwater quality in urban
areas is closely related with land use. 相似文献
15.
焦作矿区岩溶水Cl-污染原因初探 总被引：12，自引：0，他引：12
焦作裂隙岩溶水系统是我国北方岩溶区发育比较典型的系统之一，岩溶水资源丰富，水质优良，是城市供水的主要水源，据近几年水质监测，岩溶水Cl^-逐年增加，水质变咸，在对焦作矿区地质，水文地质条件，岩溶水补给来源，地表污染源和污染途径分析的基础上，建立了二维非稳定溶质运移数值模拟模型，模拟了岩溶水Cl^-时空分布，证实岩溶水Cl^- 升高是人为污染所致，不同区域岩溶水有不同的污染源和污染途径。 相似文献
16.
地下水中氯代烃的格栅水处理技术 总被引：19，自引：1，他引：19
挥发性氯代烃是地下水中检出率较高的有机污染物 ,同时也是饮用水氯气消毒的副产物 ,而它对人体的危害也已经得到了USEPA等机构的认同。文中主要从格栅材料、降解机理、影响还原性脱氯效率的因素、实际工程中应注意的问题以及发展方向等方面 ,对地下水中挥发性氯代烃的处理技术进行了阐述 ,介绍了格栅处理地下水中挥发性氯代烃的最新进展和实际意义 ,提出了格栅系统的实际应用潜力和存在的问题 ,特别是双金属系统的催化机理和催化剂失活问题 ,给国内这方面的研究者提供思路。 相似文献
17.
污染物事故性排放、工矿企业搬迁后遗留的污染场地修复面临各种问题,给地下水资源的使用带来严重威胁。地下水VOCs污染,具有易扩散迁移、毒性高、风险大的特点,修复难度较高。本文结合典型深层地下水修复案例,充分分析场地地质背景、水文地质条件等,根据污染物的特性、污染范围和分布特征,探讨各种修复技术的修复机理、修复对象和技术特点,针对VOCs污染修复进行性能比较及适用性分析。同时通过两个阶段的试验综合研究,原位和异位技术相结合,为开展类似地下水VOCs污染修复实践和管理提供了依据和思路。 相似文献
18.
Daniele Pittalis Raul Carrey Stefania Da Pelo Alberto Carletti Riccardo Biddau Rosa Cidu Fulvio Celico Albert Soler Giorgio Ghiglieri 《Hydrogeology Journal》2018,26(6):2021-2040
Agricultural coastal areas are frequently affected by the superimposition of various processes, with a combination of anthropogenic and natural sources, which degrade groundwater quality. In the coastal multi-aquifer system of Arborea (Italy)—a reclaimed morass area identified as a nitrate vulnerable zone, according to Nitrate Directive 91/676/EEC—intensive agricultural and livestock activities contribute to substantial nitrate contamination. For this reason, the area can be considered a bench test for tuning an appropriate methodology aiming to trace the nitrate contamination in different conditions. An approach combining environmental isotopes, water quality and hydrogeological indicators was therefore used to understand the origins and attenuation mechanisms of nitrate pollution and to define the relationship between contaminant and groundwater flow dynamics through the multi-aquifer characterized by sandy (SHU), alluvial (AHU), and volcanic hydrogeological (VHU) units. Various groundwater chemical pathways were consistent with both different nitrogen sources and groundwater dynamics. Isotope composition suggests a mixed source for nitrate (organic and synthetic fertilizer), especially for the AHU and SHU groundwater. Moreover, marked heterotrophic denitrification and sulfate reduction processes were detected; although, for the contamination related to synthetic fertilizer, the attenuation was inefficient at removing NO3? to less than the human consumption threshold of 50 mg/L. Various factors contributed to control the distribution of the redox processes, such as the availability of carbon sources (organic fertilizer and the presence of lagoon-deposited aquitards), well depth, and groundwater flow paths. The characterization of these processes supports water-resource management plans, future actions, and regulations, particularly in nitrate vulnerable zones. 相似文献