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1.
An activated carbon-impregnated cellulose filter was fabricated, and the capacity to remove dust and volatile organic compounds was evaluated in a laboratory. The adsorption capacities for benzene, toluene, ethyl benzene and m-xylene gases were compared by an adsorption isotherm test conducted as a preliminary test, showing that m-xylene and benzene were the most and least favorable for adsorption onto activated carbon, respectively. Cellulose filters were made with four levels of activated carbon contents, and dust removal was performed with all of the filters showing 99 % and higher efficiencies stable with a small variation during the experiment. Activated carbon content of 5 g in the unit filter area (125 g/m2) was found optimum for benzene, toluene, ethylbenzene and m-xylene removal, as it appeared that higher than 5 g activated carbon content was unnecessary for the improvement of its capacity. With increasing benzene, toluene, ethylbenzene and m-xylene loading, the highest removal rates were determined as 0.33–0.37 mg/cm2 s for as short as 0.0046 s of air filter residence time. The rapid removal was possible because of the high surface area of the activated carbon-impregnated cellulose filter provided by powdered activated carbon, which is distinguished from the granular form in conventional activated carbon towers. As fixed within a cellulose scaffolding structure, the powdered activated carbon performed excellent benzene, toluene, ethylbenzene, and m-xylene adsorption (98.9–100 %), and at the same time, particular matters were removed in average 99.7 % efficiency after being filtered through the cellulose filter sheet.  相似文献   

2.
This study investigates the variations of benzene concentration levels in district 1, situated in the north part of Tehran, capital of Iran. Thirty-three stations in five categories, namely roadsides, busy roads, residential areas, traffic intersections, and the vicinity of gas stations, were monitored during the rush hours in the afternoon once a week over a period of 1 year. Accordingly, benzene concentration levels were measured and predicted by inverse distance weight model. The recorded benzene concentration levels were then compared with those reported in other parts of the world. According to the results, the annual concentration levels of benzene was 13.85 ppb for roads with heavy traffic flow, 14.98 ppb for traffic intersections, 29.01 ppb for the vicinity of the gas stations, 3.26 ppb for residential areas, and 9.97 ppb for roadsides. The concentration of benzene in the vicinity of the gas station sampling point was higher than in the other stations, and at all locations was found to be so much more than the standard concentration levels (1.56 ppb) prescribed by Environmental Protection Agency for the ambient air quality. The results of the study revealed that the benzene concentration levels in Tehran are distinctly more than its standard level. This is mainly attributed to the poor quality of fuel and lack of a standard system for controlling petrol vapors in the gas stations.  相似文献   

3.
The single-ring aromatic hydrocarbons benzene, toluene, ethylbenzene and m-xylene (BTEX) are common and dangerous pollutants in subsurface environments. The diffusive transport of BTEX vapours through the unsaturated zone of the ground is a potential health hazard to humans, living in the vicinity of petroleum fuel contaminated sites. Past studies have shown that gas transport through the vadose zone can be influenced by moisture content due to variations in gaseous permeability, phase partitioning and aerobic biodegradation. In this particular study laboratory soil column experiments were employed to compare the diffusive transport of BTEX vapours through a sand layer of high moisture content, where biodegradation of BTEX compounds occurred, with diffusion through air-dried sand. The presence of a thin soil layer of high moisture content reduced the gaseous concentrations of benzene and toluene and stopped the migration of ethylbenzene and m-xylene vapours, demonstrating its efficiency as a barrier on the diffusive transport of BTEX vapours in unsaturated soil.  相似文献   

4.
 Contamination of groundwater by petroleum-hydrocarbons is a widespread environmental problem. Natural attenuation is a passive remedial approach to degrade and dissipate contaminants in soil and groundwater. In this study, a mass flux approach was used to calculate the contaminant mass reduction and field-scale decay rate at a gasoline spill site. The mass flux technique is accomplished using the differences in total contaminant mass flux across two cross sections of the contaminant plume. The mass flux calculation shows that up to 88% of the dissolved BTEX (benzene, toluene, ethylbenzene, and xylene isomers) removal was observed by natural attenuation processes. The efficiency of intrinsic biodegradation was evaluated by the in situ tracer method. A first-order decay model was applied for the natural attenuation and intrinsic biodegradation rate calculation. Results reveal that intrinsic biodegradation process was the major cause of the BTEX reduction among the natural attenuation mechanisms, and iron reduction was the dominant biodegradation pattern within the plume. Approximately 87% of the BTEX removal was caused by intrinsic biodegradation processes. The calculated BTEX natural attenuation and intrinsic biodegradation rates were 0.24 and 0.16% l/day, respectively. Results suggest that natural attenuation mechanisms can effectively contain the plume, and the mass flux method is useful in assessing the efficiency of the natural attenuation. Received: 6 December 1999 · Accepted: 11 July 2000  相似文献   

5.
王爽  邓天龙 《岩矿测试》2008,27(2):141-145
苯系污染物(苯、甲苯、乙苯和二甲苯)是环境中重点优先监测的致癌污染物。文章介绍了近年来国内外在水环境中苯系污染物的分析研究进展,内容主要包括:胶束电动毛细管色谱法(MECC)、吹扫捕集-气相色谱法(PT-GC)、吹扫捕集-气相色谱-质谱联用法(PT-GC-MS)、顶空固相微萃取(HS-SPME)-便携式微火焰离子化(portable GC-μFID)等联测分析技术与方法。  相似文献   

6.
反硝化增强去除乙醇对多孔介质渗透性的影响   总被引：1，自引：0，他引：1  
随着乙醇混合汽油的不断推广应用,乙醇将成为地下水中与苯、甲苯、乙苯及二甲苯的同分异构体（BTEX）共存的一种新型污染物。通过4 个含水砂柱实验,研究了乙醇存在及其强化去除对含水介质渗透性能的影响。结果表明：在有限溶解氧与反硝化增强修复条件下,乙醇去除率达92% 以上;生物过程对介质渗透能力影响程度随乙醇初始浓度、消耗速率与补充频率而变化：乙醇初始浓度接近1 000 mg/L 和3 000 mg/L 时,乙醇消耗快,补充频率高,渗透系数下降总体上有连续性,最大下降幅度达一个数量级（×10-1 cm/s）;乙醇初始浓度达到5 000 mg/L 时,渗透性下降显著,可下降两个数量级,但乙酸的积累可影响生物活性,并使得渗透性变化出现反复;当不含乙醇时,汽油溶解组分对介质渗透性能的影响相对不明显。  相似文献   

7.
River filtration system is a natural purification process to remove the pollutants in river water and make use of surface water. In this study, a series of experiments were set up with soil column test and static adsorption experiments to simulate the environmental behaviors of BTEX in the river filtration system. It was found that the environmental behaviors of BTEX in the river filtration system included adsorption and microbial degradation. Among the four components of BTEX used in the experiments, the removal rate of xylene was the highest, ethyl-benzene was second, toluene was third, and that of benzene was the lowest. The stability of the structure of benzene was the major contributor for the relatively lower degradation efficiency, and the low removal rate of toluene was due to the impact of adsorption on degradation. By comparison of the results of soil column test and static adsorption experiments, it was found that the soil–water partition coefficient K d of each component of BTEX was higher, the degradation ratio was lower. Compared with the previous study, the results of this experiment showed that when the initial concentration of the each component of BTEX reached 80 mg/L, the mixed pollution of BTEX could be removed by the river filtration system efficiently, and the average removal rate could be over 65 %. As a natural purification, river filtration system could efficiently remove the BTEX mixed pollution in a quite high concentration and protect the ground water from being contaminated. However, its purification efficiency was limited in a certain time range and concentration. It was shown in the later stage of the leaching experiment that the exudation concentration of BTEX increased, at the same time both the concentrations of the two electron acceptors increased to about the initial concentration and kept stable state until the end of the experiment, which revealed that due to accumulation of the concentration of BTEX in the soil column, the microbial activity was inhibited and then the denitrification and sulfate reduction terminated. When the adsorption saturation was achieved and microbial activity was inhibited, BTEX contamination would penetrate through the unsaturated zone and threaten the security of the ground water.  相似文献   

8.
芳香族分子示踪在海洋油气勘探中的开发和应用   总被引：5，自引：0，他引：5  
苯 (benzene)、甲苯 (toluene)、乙苯 (ethylbenzene)和二甲苯 (xylene) (缩写为BTEX)等单环芳烃化合物是原油的主要成分。地层水中苯的痕量分布作为油气藏分子示踪的研究 ,得到国外石油地球化学家们的广泛重视。Burtell等人利用测试海洋石油钻井附近地层水中苯系化合物的含量确定新井位 ,在海洋油气资源勘探方面获得了巨大成功。文中主要介绍了国内在海洋石油勘探的随钻检测和面积化探中应用该类指标的效果和相关方法。通过渤中凹陷试验区取得的地球化学成果 ,验证并揭示了芳香族化合物中分子量级的BTEX指标与油气藏的关系。BTEX指标异常与油气藏直接相关 ,与烷烃类指标相比具有高分辨、高精度特点 ,是有价值的海洋油气地球化学勘探指标。BETX指标应用的关键是高精度测试出样品中芳香族化合物的分子级含量 ,激光单原子高技术为该技术的应用提供了技术保证。在油气资源勘探中 ,利用此指标 ,结合测井、地震等地球物理方法综合分析研究可以减小多解性 ,获得较好的预测效果。  相似文献   

9.
In this study, the concentrations of ambient total suspended particulates (TSP) and their dry deposition were measured using a PS-1 sampler with dry deposition plates at a wetland sampling site in central Taiwan during a sampling period from October 2016 to December 2016. The PS-1 sampler was fixed at set distances (1.5 and 2 m) from a dry deposition plate, and sampled particulate pollutants were sampled to determine their concentrations and dry deposition rates simultaneously. A dry deposition plate 3 m from the PS-1 sampler was also used to collect dry deposition particulate. This plate was also used to compare dry depositions from ambient air, collected from new device. The results thus obtained indicated that the average dry deposition rates on the dry deposition plates that were 1.5 and 2 m from the sampler were 103.15 and 103.94 µg/m2 min, respectively, in October, 83.36 and 100.18 µg/m2 min in November, and 171.2 and 157.5 µg/m2 min in December. These dry deposition rates were compared with that 3 m away from the PS-1 sampler. The statistical t test revealed no significant differences between the dry depositions on dry deposition plates at 1.5 and 2 m from the sampler. The dry deposition rates at 1.5 and 2 m from the sampler did not differ significantly from that at 3 m from the PS-1 sampler. This study proves that a PS-1 sampler can be combined with a dry deposition plate to measure TSP concentrations and dry depositions simultaneously using a single device.  相似文献   

10.
汽油污染含水层中芳香烃的自然去除与生物降解特征   总被引：7，自引：0，他引：7  
石油烃污染地下水是一个普遍而严重的环境问题.用砂卵石、中粗砂、细砂、粉砂和粘土等在实验室内按照自然界沉积物层序制作了一个含水层物理模型,具有给水、排水、监测、抽提、淋滤与注入等功能.利用该模型开展石油烃污染地下水的特征研究结果表明,苯、甲苯、乙苯和二甲苯(benzene,toluene,ethylbenzene,xylene;BTEX)各溶解组分能够被自然去除,其中甲苯自然衰减的速率系数为0.057 5～0.150 4 d-1,二甲苯为0.068 3～0.104 6 d,乙苯大约为0.047 8 d,苯为O.017 8～0.040 6 d.甲苯与二甲苯容易被去除,然而苯的去除则需要较长的时间.作为BTEX去除反应的电子受体,溶解氧、硝酸盐在需氧或厌氧条件下具有优先利用的机会,而硫酸盐则缺乏优先利用的机会.BTEX溶解组分浓度的降低,加上电子受体浓度的降低,可以表明含水层存在需氧条件与硝酸盐还原条件下的内在生物降解作用.其意义在于通过增加含水层中电子受体的浓度,将有助于内在生物降解能力的增强,从而能够提高含水层中污染物去除的效果.  相似文献   

11.
In order to find out the distribution characteristics of BTEX in groundwater, which include Benzene, Toluene, Ethylbenzene, p-Xylene, m-Xylene, and o-Xylene, 82 groups of groundwater samples and 10 surface water samples collected from Guangzhou in Guangdong during 2005 to 2008 were tested by gas chromatography and mass spectrum(GC/MS). The result showed that the BTEX concentration in groundwater does not exceed the standard. The detection rate of BTEX is 14.63% in groundwater, and the total BTEX concentration is lower than 9.5 μg/L. Of 6 kinds of BTEX, toluene had the highest detection rate(12.20%) and detection value(9.5 μg/L), which was followed by Benzene, with the detection rate of 3.65%, and detection value of 4.9 μg/L respectively; most of samples with BTEX are distributed in Huangpu district, Baiyun district, Huadu district and other industrialized areas; this spatial distribution and urban distribution have obvious consistency. With economic development, plant expansion and population growth led to a large amount of waste water discharge, and infrastructure construction is lagging behind, indicating that rapid urbanization is a major driving force of BTEX in groundwater, and through the analysis of a typical area, it is found that benzene system surface water infiltration was an important source of BTEX in groundwater of Guangzhou.  相似文献   

12.
Anaerobic biodegradation of hydrocarbons, using a variety of terminal electron acceptors (TEAs), is increasingly being reported both in laboratory studies and in the field. Of all the petroleum hydrocarbons, benzene is considered the most problematical due to its high toxicity and relatively high aqueous solubility. These, combined with its peculiarly stable structure, mean that it has long been considered recalcitrant in all but aerobic conditions. There is now a small, but growing, literature to suggest that this may not in fact be the case. We present an assessment of the field, encompassing reviews up to 1997 and original papers published since then. It appears that benzene is indeed degraded anaerobically, but that organisms capable of doing so are not ubiquitous. In addition, benzene degradation may be competitively inhibited by the presence of more readily degraded compounds such as toluene. Certainly, the occurrence and rate of benzene attenuation under anaerobic conditions is far more site-specific than for other benzene, toluene, ethylbenzene and xylenes (BTEX) compounds. We discuss a mathematical method for modelling redox-dependent, differential degradation rates.  相似文献   

13.
《Applied Geochemistry》2003,18(10):1641-1651
Compound-specific H isotope analysis has been used to monitor bioremediation of petroleum hydrocarbons. However, the success of this approach requires a full evaluation of the isotopic effects resulting from evaporation, because light petroleum hydrocarbons undergo both biodegradation and evaporation under natural conditions. The authors determined the H isotope fractionation of common volatile petroleum hydrocarbons, including the C10–C14 n-alkanes, MTBE (tert-butyl methyl ether), and BTEX (benzene, toluene, ethylbenzene, p-xylene and o-xylene) during progressive vaporization under simulated experimental conditions. A decrease in δD values for n-alkanes of up to 33.3‰ and up to 44.5‰ for BTEX compounds when 99% of these substances had evaporated was observed. The results also show that H isotope fractionation increases with n-alkane chain length. Such fractionation patterns are interpreted in terms of competition between the decreased intermolecular binding energy in D-enriched species, and the isotope effect due to the mass difference. In contrast to hydrocarbons, methanol and ethanol show H isotopic enrichment during vaporization, indicating that H-bonding, when present in organic molecules, plays a controlling role on the vapor pressure of different isotope species.  相似文献   

14.
This research has been performed to determine the differences in microbial communities according to physicochemical properties such as concentrations of volatile aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX), dissolved oxygen (DO), electron acceptors, etc., in oil-contaminated groundwaters at Kyonggi-Do, South Korea. The properties of bacterial and microbial communities were analyzed by 16S polymerase chain reaction (PCR) denaturing gradient gel electrophoresis (DGGE) fingerprinting method and community-level physiological profiling (CLPP) using Eco-plate, respectively. Based on the DGGE fingerprints, the similarities of bacterial community structures were high with similar DO levels, and low with different DO levels. Whereas the dominant bacterial groups in GW13 (highest BTEX and lowest DO) were acidobacteria, α-proteobacteria, β-proteobacteria, γ-proteobacteria, δ-proteobacteria, and spirochetes, those in GW7 (highest BTEX and highest DO) were actinobacteria, α-proteobacteria, β-proteobacteria, γ-proteobacteria, δ-proteobacteria, and sphingobacteria. Based on the CLPP results, the groundwater samples were roughly divided into three groups: above 4 mg/L in DO (group 1: GW3 and GW7), below 4 mg/L in DO (group 2: GW8, W1, W2, W3, and BH10), and highly contaminated with BTEX (group 3: GW13). Shannon index showed that the microbial diversities and equitabilities were higher in shallower aquifer samples. Overall, this study verified that the greatest influencing factors on microbial/bacterial communities in groundwaters were DO and carbon sources, although BTEX concentration was one of the major factors.  相似文献   

15.
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   

16.
Supercritical CO2 (scCO2) is a good solvent for organic compounds such as benzene, toluene, ethyl-benzene, and xylene (BTEX), phenols, and polycyclic aromatic hydrocarbons (PAHs). Monitoring results from geological carbon sequestration (GCS) field tests have shown that organic compounds are mobilized following CO2 injection. Such results have raised concerns regarding the potential for groundwater contamination by toxic organic compounds mobilized during GCS. Knowledge of the mobilization mechanism of organic compounds and their transport and fate in the subsurface is essential for assessing risks associated with GCS. Extraction tests using scCO2 and methylene chloride (CH2Cl2) were conducted to study the mobilization of volatile organic compounds (VOCs, including BTEX), the PAH naphthalene, and n-alkanes by scCO2 from representative reservoir rock and caprock obtained from depleted oil reservoirs and coal from an enhanced coal-bed methane recovery site. Results showed that the extent of mobilization for the organic compounds was a function of the source rock. In fate and transport sand column experiments, moisture content was found to have an important influence on the transport of the organic compounds. In dry sand columns the majority of the compounds were retained in the column except benzene and toluene. In wet sand columns the mobility of the BTEX was much higher than that of naphthalene. Based upon the results determined for the reservoir rock, caprock, and coal samples studied here, the risk to aquifers from contamination by organic compounds appears to be relatively low; however, further work is necessary to fully evaluate the risks.  相似文献   

17.
An oil-refining plant site located in southern Taiwan has been identified as a petroleum-hydrocarbon [mainly methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and xylenes (BTEX)] spill site. In this study, groundwater samples collected from the site were analyzed to assess the occurrence of intrinsic MTBE biodegradation. Microcosm experiments were conducted to evaluate the feasibility of biodegrading MTBE by indigenous microorganisms under aerobic, cometabolic, iron reducing, and methanogenic conditions. Results from the field investigation and microbial enumeration indicate that the intrinsic biodegradation of MTBE and BTEX is occurring and causing the decrease in MTBE and BTEX concentrations. Microcosm results show that the indigenous microorganisms were able to biodegrade MTBE under aerobic conditions using MTBE as the sole primary substrate. The detected biodegradation byproduct, tri-butyl alcohol (TBA), can also be biodegraded by the indigenous microorganisms. In addition, microcosms with site groundwater as the medium solution show higher MTBE biodegradation rate. This indicates that the site groundwater might contain some trace minerals or organics, which could enhance the MTBE biodegradation. Results show that the addition of BTEX at low levels could also enhance the MTBE removal. No MTBE removal was detected in iron reducing and methanogenic microcosms. This might be due to the effects of low dissolved oxygen (approximately 0.3 mg/L) within the plume. The low iron reducers and methanogens (<1.8×103 cell/g of soil) observed in the aquifer also indicate that the iron reduction and methanogenesis are not the dominant biodegradation patterns in the contaminant plume. Results from the microcosm study reveal that preliminary laboratory study is required to determine the appropriate substrates and oxidation-reduction conditions to enhance the biodegradation of MTBE. Results suggest that in situ or on-site aerobic bioremediation using indigenous microorganisms would be a feasible technology to clean up this MTBE-contaminated site.  相似文献   

18.
用胶束电动毛细管色谱法对海底表层沉积物中的苯系化合物进行了分析测定。采用57cm×50μm毛细管柱，以50mmol/L十二烷基硫酸钠-2.0mmol/L四硼酸钠溶液（pH9.16）作为操作缓冲溶液，并加入φ=20%的甲醇作为有机改性剂，电压25kV，检测波长200nm，15min内苯、甲苯、乙苯和二甲苯可获得良好的分离。用峰面积定量，线性范围为2～100mg/L，最小检测浓度分别为0.75mg/L苯，0.45mg/L甲苯，0.39mg/L乙苯，0.1mg/L邻-二甲苯，0.31mg/L对-二甲苯。将该法用来分析石油勘探远景区域海底表层沉积物中的苯系化合物，检测浓度范围为(0.0x～0.x)μg/g。  相似文献   

19.
To study and determine the dependency of rheological properties and flow behaviour of organobentonites on mechanochemical modification viz. grinding and preparation temperature of organobentonite, stearyldimethylbenzylammonium-bentonites (SDMBA-bentonites) were prepared by interacting stearyldimethylbenzylammonium chloride with Indian bentonite at different reaction temperature of 40, 60, 80, 90 and 100 °C and the products were ground and passed through sieve (micronization) of 100 mesh BSS (< 150 µm) and also the product obtained at 40 °C was further processed for micronization using 150 (< 105 µm), 240 (< 63 µm) and 350 (< 45 µm) mesh BSS sieves. As there was increase in the micronization and the reaction temperature, the bulk density and particle size decreased with simultaneous increase in the surface area of SDMBA-bentonites. The enhancement of the viscosity, rheological parameters and gel index of the toluene dispersions of these SDMBA-bentonites was also observed. The decrease in particle size and bulk density with simultaneous increase in specific surface area and swelling in nitrobenzene SDMBA-bentonites leads to the formation of larger hydrogen bond network to generate improved rheological properties by increased magnitude of chemical interaction between SDMBA cations and toluene. The rheological behaviour study revealed that all the toluene–SDMBA-bentonite dispersions exhibit the shear-thinning flow behaviour and the micronization and reaction temperature influence the degree of shear-thinning, stability of the gel structures and yield stress of the dispersions. The incorporation of a mixture of 5 vol% of H2O in methanol as polar activator studied in the range of 33–100 wt% of SDMBA-bentonite reinforced the rheological properties, viscosity and gel volume, degree of shear-thinning, stability of the gel structures and yield stress of the toluene–SDMBA-bentonite dispersions. The SDMBA-bentonites with polar activator having concentration of 65 wt% exhibited the optimum rheological reinforcement. The rheological properties were found to be more enhanced by the ultrasonication relative to conventional stirring/shearing. Power law and Casson equations have been used to describe the rheological properties of the toluene–SDMBA-bentonite dispersions.  相似文献   

20.
Approximately 300 kg/day of food-grade CO2 was injected through a perforated pipe placed horizontally 2–2.3 m deep during July 9–August 7, 2008 at the MSU-ZERT field test to evaluate atmospheric and near-surface monitoring and detection techniques applicable to the subsurface storage and potential leakage of CO2. As part of this multidisciplinary research project, 80 samples of water were collected from 10 shallow monitoring wells (1.5 or 3.0 m deep) installed 1–6 m from the injection pipe, at the southwestern end of the slotted section (zone VI), and from two distant monitoring wells. The samples were collected before, during, and following CO2 injection. The main objective of study was to investigate changes in the concentrations of major, minor, and trace inorganic and organic compounds during and following CO2 injection. The ultimate goals were (1) to better understand the potential of groundwater quality impacts related to CO2 leakage from deep storage operations, (2) to develop geochemical tools that could provide early detection of CO2 intrusion into underground sources of drinking water (USDW), and (3) to test the predictive capabilities of geochemical codes against field data. Field determinations showed rapid and systematic changes in pH (7.0–5.6), alkalinity (400–1,330 mg/l as HCO3), and electrical conductance (600–1,800 μS/cm) following CO2 injection in samples collected from the 1.5 m-deep wells. Laboratory results show major increases in the concentrations of Ca (90–240 mg/l), Mg (25–70 mg/l), Fe (5–1,200 ppb), and Mn (5–1,400 ppb) following CO2 injection. These chemical changes could provide early detection of CO2 leakage into shallow groundwater from deep storage operations. Dissolution of observed carbonate minerals and desorption-ion exchange resulting from lowered pH values following CO2 injection are the likely geochemical processes responsible for the observed increases in the concentrations of solutes; concentrations generally decreased temporarily following four significant precipitation events. The DOC values obtained are 5 ± 2 mg/l, and the variations do not correlate with CO2 injection. CO2 injection, however, is responsible for detection of BTEX (e.g. benzene, 0–0.8 ppb), mobilization of metals, the lowered pH values, and increases in the concentrations of other solutes in groundwater. The trace metal and BTEX concentrations are all significantly below the maximum contaminant levels (MCLs). Sequential leaching of core samples is being carried out to investigate the source of metals and other solutes.  相似文献   

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