2012 Vol. 37, No. 2
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2012, 37(2): 207-219.
doi: 10.3799/dqkx.2012.021
Abstract:
The history of water-rock interaction studies is briefly reviewed and presented in this paper, which basically falls into three stages, namely, studies focused on water-rock interaction, water-rock-organic interaction, and finally water-rock-gas-organic-microorganism interaction. Although studies on basic geology and mineral resources have accomplished great achievements, environmental issues become increasingly important for water-rock interaction studies. Hot topics in this field mainly include groundwater evolution and global change, transport and enrichment of trace redox-sensitive elements in aquifer systems, treatment and remediation of contaminated groundwater environment, waste geologic disposal and CO2 sequestration. Due to continuous applications of new theories and technologies in physics, chemistry and biology, water-rock interaction studies are facing new opportunities and challenges, which mainly include biogeochemical studies of aquifer systems, coupling of microscale mechanisms of water-rock interaction with macroscale geochemical processes, and fractionation of isotopes as well as their applications in water-rock interactions.
The history of water-rock interaction studies is briefly reviewed and presented in this paper, which basically falls into three stages, namely, studies focused on water-rock interaction, water-rock-organic interaction, and finally water-rock-gas-organic-microorganism interaction. Although studies on basic geology and mineral resources have accomplished great achievements, environmental issues become increasingly important for water-rock interaction studies. Hot topics in this field mainly include groundwater evolution and global change, transport and enrichment of trace redox-sensitive elements in aquifer systems, treatment and remediation of contaminated groundwater environment, waste geologic disposal and CO2 sequestration. Due to continuous applications of new theories and technologies in physics, chemistry and biology, water-rock interaction studies are facing new opportunities and challenges, which mainly include biogeochemical studies of aquifer systems, coupling of microscale mechanisms of water-rock interaction with macroscale geochemical processes, and fractionation of isotopes as well as their applications in water-rock interactions.
2012, 37(2): 220-228.
doi: 10.3799/dqkx.2012.022
Abstract:
Based on a large amount of data obtained from the National Groundwater Contamination Investigation Project, the groundwater quality in North China plain, Huaihe River basin, the Yangtze River delta and the Pearl River delta in the eastern China was assessed with the single factor method, and the status of groundwater quality was assessed with detection limit and over-standard rate methods. The results show that the proportion of groundwater suitable for drinking directly (Ⅰ-Ⅲ level) or after proper treatment (Ⅳ level) is 47.9%, and the proportion not suitable for drinking directly (Ⅴ level) is 52.1%. The quality of shallow groundwater is slightly worse than that of the deep groundwater. The main compositions which affected the groundwater quality are natural chemical compositions, such as iron, manganese, fluorine, iodine, total hardness etc., whereas chemical compositions from human activities including three nitrogen (NO3-, NH4+, NO2-) compounds, cadmium, lead and trace organic composition. The groundwater contamination caused by three nitrogen compounds is distributed with regional characteristics; on the contrary, that by heavy metals is distributed with point characteristics. The contamination caused by lead and arsenic is especially serious, and toxic organic contamination presents the characteristic of high detection rate and low over-standard rate. The National Groundwater Contamination Investigation should be promoted, and the national groundwater prevention and control planning should be organized and carried out to curb the worsening situation of groundwater contamination and protect the groundwater resources and environment in China.
Based on a large amount of data obtained from the National Groundwater Contamination Investigation Project, the groundwater quality in North China plain, Huaihe River basin, the Yangtze River delta and the Pearl River delta in the eastern China was assessed with the single factor method, and the status of groundwater quality was assessed with detection limit and over-standard rate methods. The results show that the proportion of groundwater suitable for drinking directly (Ⅰ-Ⅲ level) or after proper treatment (Ⅳ level) is 47.9%, and the proportion not suitable for drinking directly (Ⅴ level) is 52.1%. The quality of shallow groundwater is slightly worse than that of the deep groundwater. The main compositions which affected the groundwater quality are natural chemical compositions, such as iron, manganese, fluorine, iodine, total hardness etc., whereas chemical compositions from human activities including three nitrogen (NO3-, NH4+, NO2-) compounds, cadmium, lead and trace organic composition. The groundwater contamination caused by three nitrogen compounds is distributed with regional characteristics; on the contrary, that by heavy metals is distributed with point characteristics. The contamination caused by lead and arsenic is especially serious, and toxic organic contamination presents the characteristic of high detection rate and low over-standard rate. The National Groundwater Contamination Investigation should be promoted, and the national groundwater prevention and control planning should be organized and carried out to curb the worsening situation of groundwater contamination and protect the groundwater resources and environment in China.
2012, 37(2): 229-237.
doi: 10.3799/dqkx.2012.023
Abstract:
To study the complicated issue of interactions between carbonate geothermal system with mid-low temperature existing in Taiyuan basin and its surrounding karst system existing in mountains, the geological evolution processes of the carbonate geothermal system were remodeled based on the analysis of geological structure and characterization of hydrochemistry and isotopic compositions of the karst water. We come to the following conclusions: (1) The carbonate geothermal system with mid-low temperature has experienced five stages of geological evolution since Yanshan Movement. and it separated from its surrounding karst system in mountains during the stable sedimentation period of Neogene to the Early Pleistocene, and then they evolved respectively; (2) The karstification of the carbonate geothermal system with mid-low temperature were due to the following two factors: ① rainfall of the late Middle Pleistocene and the early Late Pleistocene infiltrated along the fault zone (e.g. Fenhe fault), reacted with the metal sulfide in C-P coal measure strata and formed the groundwater rich in sulfuric acid. The groundwater was recharged to the carbonated geothermal reservoir and mixed with the older karst water stored in it, which facilitated the dissolution of carbonate rock; ② the pyrolyzation of carbonated rock occurred by the baking of magma from the basin basement in the late Middle Pleistocene and the early Late Pleistocene; (3) The karst water in the geothermal system formed in the late Middle Pleistocene and the early Late Pleistocene, and sealed up to now because of the good insulation of its overlying strata. Mainly controlled by the geological structure, its east-west boundaries were Dongshan fault and Xishan fault respectively and its south-north boundaries were Tianzhuang fault and north boundary of Qinxian horst respectively.
To study the complicated issue of interactions between carbonate geothermal system with mid-low temperature existing in Taiyuan basin and its surrounding karst system existing in mountains, the geological evolution processes of the carbonate geothermal system were remodeled based on the analysis of geological structure and characterization of hydrochemistry and isotopic compositions of the karst water. We come to the following conclusions: (1) The carbonate geothermal system with mid-low temperature has experienced five stages of geological evolution since Yanshan Movement. and it separated from its surrounding karst system in mountains during the stable sedimentation period of Neogene to the Early Pleistocene, and then they evolved respectively; (2) The karstification of the carbonate geothermal system with mid-low temperature were due to the following two factors: ① rainfall of the late Middle Pleistocene and the early Late Pleistocene infiltrated along the fault zone (e.g. Fenhe fault), reacted with the metal sulfide in C-P coal measure strata and formed the groundwater rich in sulfuric acid. The groundwater was recharged to the carbonated geothermal reservoir and mixed with the older karst water stored in it, which facilitated the dissolution of carbonate rock; ② the pyrolyzation of carbonated rock occurred by the baking of magma from the basin basement in the late Middle Pleistocene and the early Late Pleistocene; (3) The karst water in the geothermal system formed in the late Middle Pleistocene and the early Late Pleistocene, and sealed up to now because of the good insulation of its overlying strata. Mainly controlled by the geological structure, its east-west boundaries were Dongshan fault and Xishan fault respectively and its south-north boundaries were Tianzhuang fault and north boundary of Qinxian horst respectively.
2012, 37(2): 238-246.
doi: 10.3799/dqkx.2012.024
Abstract:
It is significant to ensure safe aquifer recharge using reclaimed water that meets the safety requirement for the sake of recovering aquifer depletion, relieving the conflict between water demand and supply, and controlling the serious environmental pollution in China. To improve the water quality of artificial recharge of groundwater using reclaimed water, we develop a security system of water quality for groundwater recharge with infiltration basin and reclaimed water and key technologies based on a series of experiments and theoretic analysis including the recharge site selection and investigation, higher-efficiency and low-cost wastewater treatment technologies, mathematical models of soil-aquifer system and the design of recharge and pumping schemes, monitoring and controlling system of water quality, safety assessment, regulations and standards, and so on. These key factors are interactive and interdependent. The pilot project in Zhengzhou demonstrates the feasibility of the security system of water quality for groundwater recharge with infiltration basin and reclaimed water, with a two-year operation showing that the water quality of the reclaimed water by the waste water treatment system satisfies the surface recharge requirement in the standard of (GB/T 19772-2005) and is better than that of the original groundwater at the site, and groundwater quality after recharge basically reaches grade III of groundwater quality (GB/T 14818-1993). It is suggested to integrate the use of reclaimed water and artificial recharge of groundwater with the utilization of water resources and environmental protection planning, to make and issue relative laws, regulations and standards, and to establish permission regulation on artificial aquifer recharge as soon as possible so as to promote artificial aquifer recharge using reclaimed water.
It is significant to ensure safe aquifer recharge using reclaimed water that meets the safety requirement for the sake of recovering aquifer depletion, relieving the conflict between water demand and supply, and controlling the serious environmental pollution in China. To improve the water quality of artificial recharge of groundwater using reclaimed water, we develop a security system of water quality for groundwater recharge with infiltration basin and reclaimed water and key technologies based on a series of experiments and theoretic analysis including the recharge site selection and investigation, higher-efficiency and low-cost wastewater treatment technologies, mathematical models of soil-aquifer system and the design of recharge and pumping schemes, monitoring and controlling system of water quality, safety assessment, regulations and standards, and so on. These key factors are interactive and interdependent. The pilot project in Zhengzhou demonstrates the feasibility of the security system of water quality for groundwater recharge with infiltration basin and reclaimed water, with a two-year operation showing that the water quality of the reclaimed water by the waste water treatment system satisfies the surface recharge requirement in the standard of (GB/T 19772-2005) and is better than that of the original groundwater at the site, and groundwater quality after recharge basically reaches grade III of groundwater quality (GB/T 14818-1993). It is suggested to integrate the use of reclaimed water and artificial recharge of groundwater with the utilization of water resources and environmental protection planning, to make and issue relative laws, regulations and standards, and to establish permission regulation on artificial aquifer recharge as soon as possible so as to promote artificial aquifer recharge using reclaimed water.
2012, 37(2): 247-252.
doi: 10.3799/dqkx.2012.025
Abstract:
There is not a well-developed method to identify accurately the risk source of groundwater pollution at present, so a risk source identification model including the vulnerability and contaminant source, coupling of many factors, was constructed based on the comprehensive analysis of contaminant source structure and the evaluation of contaminant transport process in this study. Hazard assessment parameters system of contaminant source was established from the characteristics of sources and pollutants. Groundwater vulnerability index and potential hazard assessment index of contaminant source were used to evaluate and classify the risk source by product model. The method was applied to a groundwater supply source, and which identified high-risk areas of groundwater contamination. The results show that risk source of groundwater pollution was effectively determined by contaminant source and the vulnerability assessment, and the method was of great importance for the prevention of groundwater contamination and effective supervision of contaminant source.
There is not a well-developed method to identify accurately the risk source of groundwater pollution at present, so a risk source identification model including the vulnerability and contaminant source, coupling of many factors, was constructed based on the comprehensive analysis of contaminant source structure and the evaluation of contaminant transport process in this study. Hazard assessment parameters system of contaminant source was established from the characteristics of sources and pollutants. Groundwater vulnerability index and potential hazard assessment index of contaminant source were used to evaluate and classify the risk source by product model. The method was applied to a groundwater supply source, and which identified high-risk areas of groundwater contamination. The results show that risk source of groundwater pollution was effectively determined by contaminant source and the vulnerability assessment, and the method was of great importance for the prevention of groundwater contamination and effective supervision of contaminant source.
2012, 37(2): 253-262.
doi: 10.3799/dqkx.2012.026
Abstract:
Three hydrological years' automatic monitoring (from January, 2007 to June, 2010) was made in the discharge area of karst subterranean stream system covered by virgin forest in soil shortage environment with hydro-chemical auto-recordable instrument. In order to study the characteristics of water-carbon regime of discharge from this subterranean stream system, the methods of water balance calculation, karst water discharge recession analysis and H, O stable isotope analysis were used. The results show that: firstly, the evapotranspiration of virgin forest is unexpectedly high, indicated by low infiltration coefficient and low subterranean river runoff generation; secondly, under the conditions of shortage of soil cover, virgin forest has only moderate ability of regulation and control of hydrological (Q) and hydrochemical (HCO3- concentration) processes, which results in the karstification intensity and the relevant carbon sink capacity decrease. These characteristics reflect that soil plays important roles in the regulation and control of water resources and carbon cycle.
Three hydrological years' automatic monitoring (from January, 2007 to June, 2010) was made in the discharge area of karst subterranean stream system covered by virgin forest in soil shortage environment with hydro-chemical auto-recordable instrument. In order to study the characteristics of water-carbon regime of discharge from this subterranean stream system, the methods of water balance calculation, karst water discharge recession analysis and H, O stable isotope analysis were used. The results show that: firstly, the evapotranspiration of virgin forest is unexpectedly high, indicated by low infiltration coefficient and low subterranean river runoff generation; secondly, under the conditions of shortage of soil cover, virgin forest has only moderate ability of regulation and control of hydrological (Q) and hydrochemical (HCO3- concentration) processes, which results in the karstification intensity and the relevant carbon sink capacity decrease. These characteristics reflect that soil plays important roles in the regulation and control of water resources and carbon cycle.
2012, 37(2): 263-268.
doi: 10.3799/dqkx.2012.027
Abstract:
On the basis of field investigation, batch experiments and column experiments have been conducted to elucidate dynamics of colloid release concentration and amount from the coastal aquifer under different sodium adsorption ratios (SAR). The differences of colloids release in different aqueous mediums are identified, and the permeability changes of aqueous mediums are investigated in the process of colloid release. The results show that the release capacity of colloidal particles from the aqueous mediums decrease with the increasing of sodium adsorption ratio (SAR) in the mixed solution system of NaCl and CaCl2, and Ca2+ inhibits the release of the colloid. From the column experiment, it is found that a little colloid particles of silty soil are released at the SAR of influent is 0 and 8, and begin to release obviously when the SAR of influent is ∞, and the release amount of colloidal particles from the aqueous mediums increases gradually with the increasing of pore volumes, and reaches the maximum at pore volumes of 52, then the concentration reduces gradually. The total cumulative release amount of colloidal particles from silty soil is 0.13 mg/g. Very little colloid particles of the fine silty and medium sand are released. The permeability loss of silty soil, fine silty and medium sand are 98.2%, 86.7% and 95.9% respectively in the process of colloid release. The permeability losses of aqueous mediums are mainly due to the spatial redistribution of released colloidal particles in the media.
On the basis of field investigation, batch experiments and column experiments have been conducted to elucidate dynamics of colloid release concentration and amount from the coastal aquifer under different sodium adsorption ratios (SAR). The differences of colloids release in different aqueous mediums are identified, and the permeability changes of aqueous mediums are investigated in the process of colloid release. The results show that the release capacity of colloidal particles from the aqueous mediums decrease with the increasing of sodium adsorption ratio (SAR) in the mixed solution system of NaCl and CaCl2, and Ca2+ inhibits the release of the colloid. From the column experiment, it is found that a little colloid particles of silty soil are released at the SAR of influent is 0 and 8, and begin to release obviously when the SAR of influent is ∞, and the release amount of colloidal particles from the aqueous mediums increases gradually with the increasing of pore volumes, and reaches the maximum at pore volumes of 52, then the concentration reduces gradually. The total cumulative release amount of colloidal particles from silty soil is 0.13 mg/g. Very little colloid particles of the fine silty and medium sand are released. The permeability loss of silty soil, fine silty and medium sand are 98.2%, 86.7% and 95.9% respectively in the process of colloid release. The permeability losses of aqueous mediums are mainly due to the spatial redistribution of released colloidal particles in the media.
2012, 37(2): 269-275.
doi: 10.3799/dqkx.2012.028
Abstract:
Tóth proposed hierarchical groundwater flow-systems in the complex basin based on given head upper-boundaries in the 1960's. However, when the flow patterns with the given head upper-boundary are dealt with (so called Tóth method), changes of hydraulic conductivities or basin geometry result in changes of water budget in a basin synchronously. At the same time, the number of potential sources and sinks and their positions are fixed by the given head upper-boundaries which are not consistent with the actual condition and may result in wrong groundwater flow patterns and their transformation. Based on summarizing the hierarchical characteristics of groundwater flow systems on sand-box experiments, we propose a numerical simulation of groundwater flow patterns using flux as upper-boundaries (so called CUG-GWFS method). The simulated results show that five sequential flow patterns may develop in the basin with several possible potential sources and sinks: (a) simple regional only, (b) nested local-regional, (c) nested local-intermediate-regional, (d) nested local-intermediate, and (e) just local flow systems. The basinal groundwater flow patterns are dominated by the infiltration intensity, hydraulic conductivities, the ratio of length to depth and the number of potential sources and sinks and their positions. The basinal flow patterns will transform orderly as the five patterns above with the increasing of the ratio of infiltration intensity to hydraulic conductivity Ric or the ratio of length to depth of a basin Rld while the rest conditions remain the same.
Tóth proposed hierarchical groundwater flow-systems in the complex basin based on given head upper-boundaries in the 1960's. However, when the flow patterns with the given head upper-boundary are dealt with (so called Tóth method), changes of hydraulic conductivities or basin geometry result in changes of water budget in a basin synchronously. At the same time, the number of potential sources and sinks and their positions are fixed by the given head upper-boundaries which are not consistent with the actual condition and may result in wrong groundwater flow patterns and their transformation. Based on summarizing the hierarchical characteristics of groundwater flow systems on sand-box experiments, we propose a numerical simulation of groundwater flow patterns using flux as upper-boundaries (so called CUG-GWFS method). The simulated results show that five sequential flow patterns may develop in the basin with several possible potential sources and sinks: (a) simple regional only, (b) nested local-regional, (c) nested local-intermediate-regional, (d) nested local-intermediate, and (e) just local flow systems. The basinal groundwater flow patterns are dominated by the infiltration intensity, hydraulic conductivities, the ratio of length to depth and the number of potential sources and sinks and their positions. The basinal flow patterns will transform orderly as the five patterns above with the increasing of the ratio of infiltration intensity to hydraulic conductivity Ric or the ratio of length to depth of a basin Rld while the rest conditions remain the same.
2012, 37(2): 276-282.
doi: 10.3799/dqkx.2012.029
Abstract:
Badain Jaran desert is well-known for its distribution of many megadunes and lakes. However, opinions about the formation of these megadunes and lakes vary from person to person until recently. Actually, their formation is directly related to the circulation and alternation of the groundwater in this area. According to the previous research, combining with the current hydro-geological investigation in the study area, this article discusses the formation mechanisms of megadunes and lakes in Badain Jaran desert. It is found that lakes in the desert formed mainly as a result of the lateral recharge of groundwater both from Yabulai Mountain and megadunes. The formation of megadunes is closely related with the rainfall and groundwater in the area. The formation and coexistent relationship between megadunes and lakes are as follows: the megadunes formed firstly, and then the lakes appeared. That means megadunes are a necessary condition for the formation of lakes there.
Badain Jaran desert is well-known for its distribution of many megadunes and lakes. However, opinions about the formation of these megadunes and lakes vary from person to person until recently. Actually, their formation is directly related to the circulation and alternation of the groundwater in this area. According to the previous research, combining with the current hydro-geological investigation in the study area, this article discusses the formation mechanisms of megadunes and lakes in Badain Jaran desert. It is found that lakes in the desert formed mainly as a result of the lateral recharge of groundwater both from Yabulai Mountain and megadunes. The formation of megadunes is closely related with the rainfall and groundwater in the area. The formation and coexistent relationship between megadunes and lakes are as follows: the megadunes formed firstly, and then the lakes appeared. That means megadunes are a necessary condition for the formation of lakes there.
2012, 37(2): 283-288.
doi: 10.3799/dqkx.2012.030
Abstract:
The brine resource in the Qianjiang depression in Jianghan basin is rich in the brine resource because alternating deposits of gypsum mudstone, mudstone as well as sandstone of Qianjiang Formation form the potential sites for CO2 geological storage. However, the salinity in Qianjiang Formation is very high with the average value up to 283.25 g/L. The purpose of this study is to investigate the physical and chemical responses under the condition of high salinity. The results show that the CO2 dissolved in brine and sequestered in minerals decline significantly as a result of directly injecting CO2 into the brine with high salinity, which may affect the storage safety. Moreover, high salinity will lead to serious salt precipitation around the injection well which may reduce the injectivity. High salinity can also cause the high pressure build up around the injection well. The method of CO2 injection combined with brine production can effectively mitigate the severe pressure build up and salt precipitation. In this way, we can maximize the utilization of brine resource and the underground space and achieve both the econimic benifits and the environmental benefits.
The brine resource in the Qianjiang depression in Jianghan basin is rich in the brine resource because alternating deposits of gypsum mudstone, mudstone as well as sandstone of Qianjiang Formation form the potential sites for CO2 geological storage. However, the salinity in Qianjiang Formation is very high with the average value up to 283.25 g/L. The purpose of this study is to investigate the physical and chemical responses under the condition of high salinity. The results show that the CO2 dissolved in brine and sequestered in minerals decline significantly as a result of directly injecting CO2 into the brine with high salinity, which may affect the storage safety. Moreover, high salinity will lead to serious salt precipitation around the injection well which may reduce the injectivity. High salinity can also cause the high pressure build up around the injection well. The method of CO2 injection combined with brine production can effectively mitigate the severe pressure build up and salt precipitation. In this way, we can maximize the utilization of brine resource and the underground space and achieve both the econimic benifits and the environmental benefits.
2012, 37(2): 289-293.
doi: 10.3799/dqkx.2012.031
Abstract:
Using narrow-slit experimental plants, this paper simulates behavioral features of dynamic adsorption, physical desorption, chemical desorption of single Mn system, single Cr (Ⅵ) system and Mn-Cr (Ⅵ) complex system in karst groundwater system. The results indicate that: (1) Under a single system, soil absorption rate of Mn is much larger than that of Cr (Ⅵ); and the two are of specific-orientated adsorption, and difficult to be activated and migrate; (2) Under complex system, the two metals both show absorption rate reduction, desorption rate increase and easy to be activated, migrate; (3) the two metals both show synergistic action, however the effect of Mn to Cr (Ⅵ) is smaller than that of Cr (Ⅵ) to Mn.
Using narrow-slit experimental plants, this paper simulates behavioral features of dynamic adsorption, physical desorption, chemical desorption of single Mn system, single Cr (Ⅵ) system and Mn-Cr (Ⅵ) complex system in karst groundwater system. The results indicate that: (1) Under a single system, soil absorption rate of Mn is much larger than that of Cr (Ⅵ); and the two are of specific-orientated adsorption, and difficult to be activated and migrate; (2) Under complex system, the two metals both show absorption rate reduction, desorption rate increase and easy to be activated, migrate; (3) the two metals both show synergistic action, however the effect of Mn to Cr (Ⅵ) is smaller than that of Cr (Ⅵ) to Mn.
2012, 37(2): 294-300.
doi: 10.3799/dqkx.2012.032
Abstract:
Artificial synthesized nanoscale zero-valent iron (NZVI) was used in the laboratory for the removal of As(Ⅲ). The average BET surface area of particles was 49.16 m2/g, with a diameter in the range of 20-40 nm. Batch experiments were carried out to study the efficiency of inorganic arsenic removal and adsorption kinetics by NZVI. The results show that As (Ⅲ) can be removed efficiently by NZVI at pH 7, 20℃. The removal rate for As (Ⅲ) is over 99% within 60 minutes by reacting 910 μg/L As (Ⅲ) with 0.1 g NZVI. The As (Ⅲ) adsorption process follows the pseudo-first-order kinetic expression. The surface-area-normalized rate coefficient kSA is 2.6 mL·m-2·min-1 for As (Ⅲ). The equilibrium adsorption data fit Langmuir and Freundlich adsorption model well, with values of the constants at the regression coefficient (R2 > 0.95) for both models. The monolayer adsorption capacity of the sorbent, as obtained from the Langmuir isotherm, 76.3 mg/g is of NZVI. 21% As (Ⅲ) adsorpted on NZVI was found to desorption by sodium hydroxide solution (0.1 M). The effect of competing anions shows SiO32- and H2PO4- markedly decrease with the removal of As (III), while the effect of other anions is insignificant. The mechanism of As removal is adsorption and coprecipitation.
Artificial synthesized nanoscale zero-valent iron (NZVI) was used in the laboratory for the removal of As(Ⅲ). The average BET surface area of particles was 49.16 m2/g, with a diameter in the range of 20-40 nm. Batch experiments were carried out to study the efficiency of inorganic arsenic removal and adsorption kinetics by NZVI. The results show that As (Ⅲ) can be removed efficiently by NZVI at pH 7, 20℃. The removal rate for As (Ⅲ) is over 99% within 60 minutes by reacting 910 μg/L As (Ⅲ) with 0.1 g NZVI. The As (Ⅲ) adsorption process follows the pseudo-first-order kinetic expression. The surface-area-normalized rate coefficient kSA is 2.6 mL·m-2·min-1 for As (Ⅲ). The equilibrium adsorption data fit Langmuir and Freundlich adsorption model well, with values of the constants at the regression coefficient (R2 > 0.95) for both models. The monolayer adsorption capacity of the sorbent, as obtained from the Langmuir isotherm, 76.3 mg/g is of NZVI. 21% As (Ⅲ) adsorpted on NZVI was found to desorption by sodium hydroxide solution (0.1 M). The effect of competing anions shows SiO32- and H2PO4- markedly decrease with the removal of As (III), while the effect of other anions is insignificant. The mechanism of As removal is adsorption and coprecipitation.
2012, 37(2): 301-306.
doi: 10.3799/dqkx.2012.033
Abstract:
Geological storage is one of the most effective means to reduce the anthropogenic greenhouse gas emissions to mitigate the worsening global warming. Depleted oil-gas reservoirs, coal seams and deep saline aquifers are potential sites for CO2 geological storage of which saline aquifer has the greatest potential for sequestration. Among the many effective mechanisms, dissolving storage is characterized by large storage capacity, long action time and high safety. When evaluating the storage capacity of a deep saline aquifer, CO2 solubility becomes a key parameter. In this paper, an experimental method is proposed and used to measure the CO2 solubility in Shanxi Formation water. Ordos Basin is an important energy base for China which releases a lot of high concentration CO2. Studies show CO2 geological storage is possible in Ordos Basin since its Shanxi Formation forms many source-reservoir-cap assemblages, and it is of great importance both in theory and practice to probe into CO2 solubility in Shanxi Formation water of Ordos Basin. In this paper, chemical composition of Shanxi Formation water collected from the Ordos Basin were analyzed. CO2 solubilities in the artificial synthetic Shanxi Formation waterwere measured at 40-80℃, 8-12 MPa pressure. The results can be used for the evaluation of the CO2 storage capacity in deep saline aquifer of Ordos Basin.
Geological storage is one of the most effective means to reduce the anthropogenic greenhouse gas emissions to mitigate the worsening global warming. Depleted oil-gas reservoirs, coal seams and deep saline aquifers are potential sites for CO2 geological storage of which saline aquifer has the greatest potential for sequestration. Among the many effective mechanisms, dissolving storage is characterized by large storage capacity, long action time and high safety. When evaluating the storage capacity of a deep saline aquifer, CO2 solubility becomes a key parameter. In this paper, an experimental method is proposed and used to measure the CO2 solubility in Shanxi Formation water. Ordos Basin is an important energy base for China which releases a lot of high concentration CO2. Studies show CO2 geological storage is possible in Ordos Basin since its Shanxi Formation forms many source-reservoir-cap assemblages, and it is of great importance both in theory and practice to probe into CO2 solubility in Shanxi Formation water of Ordos Basin. In this paper, chemical composition of Shanxi Formation water collected from the Ordos Basin were analyzed. CO2 solubilities in the artificial synthetic Shanxi Formation waterwere measured at 40-80℃, 8-12 MPa pressure. The results can be used for the evaluation of the CO2 storage capacity in deep saline aquifer of Ordos Basin.
2012, 37(2): 307-312.
doi: 10.3799/dqkx.2012.034
Abstract:
Anaerobic biological reduction of perchlorate in the presence of nitrate using is studied acetate as carbon source. In addition, effects of different nitrate concentrations on perchlorate reduction are researched. The results show that 10mg/L of perchlorate can be removed by the enriched microorganisms in different nitrate-reducing conditions. Evidence is also presented demonstrating that perchlorate reduction is not inhibited under 20mg/L nitrate-reducing condition. However, under 100mg/L, 200mg/L and 500mg/L nitrate-reducing conditions, perchlorate removal is observed with longer lag periods of 7d, 13d and 38d respectively. At the initial period of reactions, nitrate, as a more favorable electron acceptor, is more easily used by the microbes. With the rapid reduction of nitrate and nitrite accumulation, it is reasonable to propose that the electronic competition and the toxic effect of a certain level of nitrite, particularly in large quantity, on the activity of perchlorate-reducing bacteria, may temporarily delay perchlorate biological reduction.
Anaerobic biological reduction of perchlorate in the presence of nitrate using is studied acetate as carbon source. In addition, effects of different nitrate concentrations on perchlorate reduction are researched. The results show that 10mg/L of perchlorate can be removed by the enriched microorganisms in different nitrate-reducing conditions. Evidence is also presented demonstrating that perchlorate reduction is not inhibited under 20mg/L nitrate-reducing condition. However, under 100mg/L, 200mg/L and 500mg/L nitrate-reducing conditions, perchlorate removal is observed with longer lag periods of 7d, 13d and 38d respectively. At the initial period of reactions, nitrate, as a more favorable electron acceptor, is more easily used by the microbes. With the rapid reduction of nitrate and nitrite accumulation, it is reasonable to propose that the electronic competition and the toxic effect of a certain level of nitrite, particularly in large quantity, on the activity of perchlorate-reducing bacteria, may temporarily delay perchlorate biological reduction.
2012, 37(2): 313-318.
doi: 10.3799/dqkx.2012.035
Abstract:
This research built up a dual-chambered electricigens-pyrite equipment. Using single crystal pyrite as electron acceptor of electricigens, and the electron transfer process was analyzed by electrochemical methods. Compared with graphite electrode, the maximum system power density increased by 132.9% and polarization resistance of EIS decreased by 98.8% with a single crystal pyrite electrode. The data show a favorable electron transfer activity between electricigens and single crystal pyrite. The electron transfer process is related to the two electrode reactions, of which one is microbial oxidation by electricigens, and the other is reduction at 0.34 V (vs. SCE) by single crystal pyrite as electron acceptor.
This research built up a dual-chambered electricigens-pyrite equipment. Using single crystal pyrite as electron acceptor of electricigens, and the electron transfer process was analyzed by electrochemical methods. Compared with graphite electrode, the maximum system power density increased by 132.9% and polarization resistance of EIS decreased by 98.8% with a single crystal pyrite electrode. The data show a favorable electron transfer activity between electricigens and single crystal pyrite. The electron transfer process is related to the two electrode reactions, of which one is microbial oxidation by electricigens, and the other is reduction at 0.34 V (vs. SCE) by single crystal pyrite as electron acceptor.
2012, 37(2): 319-326.
doi: 10.3799/dqkx.2012.036
Abstract:
To explore the characters and their possible mechanisms for the jointed effects of inorganic salts and surfactant on adsorption and desorption of phenanthrene in loess soils, batch tests were conducted with NaCl and MgCl2, SDBS selected as inorganic salt and surfactant models respectively. Results show that if one of NaCl (≥0.1 mol/L), MgCl2 and SDBS is added into the studied solution, the adsorption equilibrium time can be shortened, and adsorption capacity can be increased. In other words, this addition enhances the adsorption, and the enhancement is strengthened with increased additive concentration with enhancement abilities ranked as MgCl2 > SDBS > NaCl. Under this addition condition, the adsorption rates follow both Freundlich and Henry equations. When both of NaCl and MgCl2 are simultaneously added, the adsorption is also enhanced as additive effect. When salts and SDBD are added simultaneously, their joint effect, is also to enhance the adsorption as additive effect, tending to antagonism, especially when MgCl2 concentration is relatively high, because bath has affected the constant pore of the soil. Desorption tests determines that joint effects of NaCl, MgCl2 and SDBS added are to speed up desorption, shorten adsorption equilibrium time, and weaken its hysteresis. Therefore, inorganic salts and surfactants added with suitable doses are feasible for PAHs polluted groundwater system remediation.
To explore the characters and their possible mechanisms for the jointed effects of inorganic salts and surfactant on adsorption and desorption of phenanthrene in loess soils, batch tests were conducted with NaCl and MgCl2, SDBS selected as inorganic salt and surfactant models respectively. Results show that if one of NaCl (≥0.1 mol/L), MgCl2 and SDBS is added into the studied solution, the adsorption equilibrium time can be shortened, and adsorption capacity can be increased. In other words, this addition enhances the adsorption, and the enhancement is strengthened with increased additive concentration with enhancement abilities ranked as MgCl2 > SDBS > NaCl. Under this addition condition, the adsorption rates follow both Freundlich and Henry equations. When both of NaCl and MgCl2 are simultaneously added, the adsorption is also enhanced as additive effect. When salts and SDBD are added simultaneously, their joint effect, is also to enhance the adsorption as additive effect, tending to antagonism, especially when MgCl2 concentration is relatively high, because bath has affected the constant pore of the soil. Desorption tests determines that joint effects of NaCl, MgCl2 and SDBS added are to speed up desorption, shorten adsorption equilibrium time, and weaken its hysteresis. Therefore, inorganic salts and surfactants added with suitable doses are feasible for PAHs polluted groundwater system remediation.
2012, 37(2): 327-331.
doi: 10.3799/dqkx.2012.037
Abstract:
Adsorption behavior of trichloroethylene on the simulated orano-mineral complex and the mixture of mineral and humic acid were comparatively studied with batch technique. The results show that sorption capacity of trichloroethylene by kaolinite and quartz sand is quite small compared to that of the humic acid. Trichloroethylene sorption to the simulated organo-minerals exhibits linear isotherm and Koc decreases with the increase of the humic acid loading, being less than that of the pure humic acid. The interaction of humic acid and simulated minerals affects the sorption of trichloroethylene. Based on the analysis of conformation of the humic acid in the complexes, a model of organo-mineral is generalized to explain the results well.
Adsorption behavior of trichloroethylene on the simulated orano-mineral complex and the mixture of mineral and humic acid were comparatively studied with batch technique. The results show that sorption capacity of trichloroethylene by kaolinite and quartz sand is quite small compared to that of the humic acid. Trichloroethylene sorption to the simulated organo-minerals exhibits linear isotherm and Koc decreases with the increase of the humic acid loading, being less than that of the pure humic acid. The interaction of humic acid and simulated minerals affects the sorption of trichloroethylene. Based on the analysis of conformation of the humic acid in the complexes, a model of organo-mineral is generalized to explain the results well.
2012, 37(2): 332-336.
doi: 10.3799/dqkx.2012.038
Abstract:
Atrazine is a typical environmental hormone and iron oxide which is one of the major components in the soil minerals. Studying of iron oxide on the adsorption behavior of atrazine facilitates the understanding of acts of environmental hormones in the environment. In this paper, the effects of the atrazine polluted soil and mixture of iron oxides on the adsorption and desorption of atrazine is studied, and three different ratios of soil and a mixture of iron oxides on the atrazine desorption are investigated. In addition, the main factors are found by means of changing factors such as desorption time, temperature, and pH value. Results show that temperature, pH, ratio of iron oxides and soil all affect the desorption in different degrees. Dynamic equilibrium of the effect of the mixture on the desorption could be achieved in about 4 hours generally. Acid or alkaline environment and the appropriate temperature enhance the desorption, and the mixture obviously has better desorption effect than the original soil.
Atrazine is a typical environmental hormone and iron oxide which is one of the major components in the soil minerals. Studying of iron oxide on the adsorption behavior of atrazine facilitates the understanding of acts of environmental hormones in the environment. In this paper, the effects of the atrazine polluted soil and mixture of iron oxides on the adsorption and desorption of atrazine is studied, and three different ratios of soil and a mixture of iron oxides on the atrazine desorption are investigated. In addition, the main factors are found by means of changing factors such as desorption time, temperature, and pH value. Results show that temperature, pH, ratio of iron oxides and soil all affect the desorption in different degrees. Dynamic equilibrium of the effect of the mixture on the desorption could be achieved in about 4 hours generally. Acid or alkaline environment and the appropriate temperature enhance the desorption, and the mixture obviously has better desorption effect than the original soil.
2012, 37(2): 337-344.
doi: 10.3799/dqkx.2012.039
Abstract:
Treatment of wastewater containing Benzontriazole with an electro-coagulation method has good prospects of application. Furthermore, a discussion on the influencing factors of treatment can provide a basis for establishing practical wastewater treatment projects. A series of data are gained by changing the experimental conditions of influencing factors in the artificial compounded simulated wastewater based on the laboratory experiments. The results showed that the current density, the interval between polar plates, the electrolyzation time, the pH value of raw water, the initial COD concentration of the raw water, the numbers of polar plates, the tank volume rate, the flocculation reaction time and the composition of wastewater, all above influence the treating effects. Based on the results, the experimental conditions of all influencing factors were optimized. Besides, the feasibility of optimization of experimental conditions and the practicability of treating wastewater containing benzotriazole with electro-coagulation method were validated by an actual wastewater treating experiment.
Treatment of wastewater containing Benzontriazole with an electro-coagulation method has good prospects of application. Furthermore, a discussion on the influencing factors of treatment can provide a basis for establishing practical wastewater treatment projects. A series of data are gained by changing the experimental conditions of influencing factors in the artificial compounded simulated wastewater based on the laboratory experiments. The results showed that the current density, the interval between polar plates, the electrolyzation time, the pH value of raw water, the initial COD concentration of the raw water, the numbers of polar plates, the tank volume rate, the flocculation reaction time and the composition of wastewater, all above influence the treating effects. Based on the results, the experimental conditions of all influencing factors were optimized. Besides, the feasibility of optimization of experimental conditions and the practicability of treating wastewater containing benzotriazole with electro-coagulation method were validated by an actual wastewater treating experiment.
2012, 37(2): 345-349.
doi: 10.3799/dqkx.2012.040
Abstract:
In order to study the effects and mechanism of adsorption of As (V) in water by granite-derived red soil, the batch experiments were conducted and the influence on the adsorption of As (V) by granite-derived red soil of the initial As concentration, the reaction time, the reaction temperature and the pH value were studied respectively. When the initial As concentration was below 5.0 mg/L, the removal rate of As was higher than 97%. With the increase of the initial As concentration, the removal rate decreased gradually. In the initial stage of the reaction(0-120 min), the removal rate increased rapidly to about 95%, and then it increased slowly to about 97% at 720 min. The system temperature had a small effect on the adsorption. And with the rising temperature, the removal rate only increased a little. The removal rate decreased gradually while the pH value increased. The orthogonal test indicates that the removal rate was highest when the initial As concentration, the reaction time, the pH value and the reaction temperature were respectively 5.0 mg/L, 120 min, 5.0 and 40℃.
In order to study the effects and mechanism of adsorption of As (V) in water by granite-derived red soil, the batch experiments were conducted and the influence on the adsorption of As (V) by granite-derived red soil of the initial As concentration, the reaction time, the reaction temperature and the pH value were studied respectively. When the initial As concentration was below 5.0 mg/L, the removal rate of As was higher than 97%. With the increase of the initial As concentration, the removal rate decreased gradually. In the initial stage of the reaction(0-120 min), the removal rate increased rapidly to about 95%, and then it increased slowly to about 97% at 720 min. The system temperature had a small effect on the adsorption. And with the rising temperature, the removal rate only increased a little. The removal rate decreased gradually while the pH value increased. The orthogonal test indicates that the removal rate was highest when the initial As concentration, the reaction time, the pH value and the reaction temperature were respectively 5.0 mg/L, 120 min, 5.0 and 40℃.
2012, 37(2): 350-356.
doi: 10.3799/dqkx.2012.041
Abstract:
In order to identify sources of nitrate in groundwater from the wastewater irrigated area, the southern part of Shijiazhuang City, 5 soil/wastewater samples from potential contamination sources and 19 groundwater samples were collected for chemical and nitrogen isotopic analyses. Irrigation wastewater has relatively low δ15N value of 4.0‰, and soil applied with commercial fertilizer and beneath animal waste piles has δ15N values of 1.4‰ and 12.4‰, respectively. The distribution of δ15N values of sediment from about 30 m-thick vadose zone beneath the vegetable growth plot only applied with animal wastes shows that NO3- derived from animal wastes has transported to the lower vadose zone with the mean δ15N value of 10.9‰. Sediment samples collected from the thick vadose zone beneath the farmland only irrigated with wastewater indicates that the deep vadose zone below the soil layer has narrow range of δ15N values with the mean δ15N value of 5.7‰. Groundwater from the wastewater irrigated area has NO3- concentration ranging from 52.6 mg/L to 124.5 mg/L with a mean value of 79.72 mg/L, and δ15N values of NO3- ranging from 5.3 to 8.3‰ with a mean value of 7.0‰ except a sample from a deep well. δ15N values of groundwater from the wastewater irrigated area are higher than those from the deep vadose zone beneath the wastewater irrigated area, which indicates that other sources with higher δ15N values contribute to groundwater NO3-. The other sources are mainly human and animal wastes. NO3- in groundwater from the wastewater irrigated area are derived from irrigation wastewater accounting for about 76% and from human and animal wastes accounting for about 24%, respectively. Wastewater irrigation and human/animal wastes management should be strengthened to prevent groundwater NO3- contamination in the wastewater irrigated area.
In order to identify sources of nitrate in groundwater from the wastewater irrigated area, the southern part of Shijiazhuang City, 5 soil/wastewater samples from potential contamination sources and 19 groundwater samples were collected for chemical and nitrogen isotopic analyses. Irrigation wastewater has relatively low δ15N value of 4.0‰, and soil applied with commercial fertilizer and beneath animal waste piles has δ15N values of 1.4‰ and 12.4‰, respectively. The distribution of δ15N values of sediment from about 30 m-thick vadose zone beneath the vegetable growth plot only applied with animal wastes shows that NO3- derived from animal wastes has transported to the lower vadose zone with the mean δ15N value of 10.9‰. Sediment samples collected from the thick vadose zone beneath the farmland only irrigated with wastewater indicates that the deep vadose zone below the soil layer has narrow range of δ15N values with the mean δ15N value of 5.7‰. Groundwater from the wastewater irrigated area has NO3- concentration ranging from 52.6 mg/L to 124.5 mg/L with a mean value of 79.72 mg/L, and δ15N values of NO3- ranging from 5.3 to 8.3‰ with a mean value of 7.0‰ except a sample from a deep well. δ15N values of groundwater from the wastewater irrigated area are higher than those from the deep vadose zone beneath the wastewater irrigated area, which indicates that other sources with higher δ15N values contribute to groundwater NO3-. The other sources are mainly human and animal wastes. NO3- in groundwater from the wastewater irrigated area are derived from irrigation wastewater accounting for about 76% and from human and animal wastes accounting for about 24%, respectively. Wastewater irrigation and human/animal wastes management should be strengthened to prevent groundwater NO3- contamination in the wastewater irrigated area.
2012, 37(2): 357-364.
doi: 10.3799/dqkx.2012.042
Abstract:
The purpose of this study is to explore the biological karst developing mechanism at the coexistence condition of the sulfate and carbonate rock. The study focuses on the geochemical processes in water-rock-bacteria system by tracing the stable sulfur isotope (34S) fractionation through laboratory experiment combined with the isotope data of the pyrite filling in Ordovician weathering crust in the Ordos basin. The results suggest that the H2S produced by bacterial sulfate reduction (BSR) is characterized by a significant isotope fractionation of 34S, which was controlled by temperature and the SO42- concentration from the dissolution of sulfate rocks in the system. Bacterial sulfate reduction in the experimental system provides an evidence for biological karst on sulfate rocks, and gives a good interpretation for the feature of karst development below the Ordovician weathering crust, Ordos basin. In addition, the presence of pyrite and compacted released water karst confirms that bacterial sulfate reduction took place within the weathering crust during the burial stage. The results provide a new perspective for the analysis of the formation of oil-gas reservoir and the exploration of petroleum gas geology resources.
The purpose of this study is to explore the biological karst developing mechanism at the coexistence condition of the sulfate and carbonate rock. The study focuses on the geochemical processes in water-rock-bacteria system by tracing the stable sulfur isotope (34S) fractionation through laboratory experiment combined with the isotope data of the pyrite filling in Ordovician weathering crust in the Ordos basin. The results suggest that the H2S produced by bacterial sulfate reduction (BSR) is characterized by a significant isotope fractionation of 34S, which was controlled by temperature and the SO42- concentration from the dissolution of sulfate rocks in the system. Bacterial sulfate reduction in the experimental system provides an evidence for biological karst on sulfate rocks, and gives a good interpretation for the feature of karst development below the Ordovician weathering crust, Ordos basin. In addition, the presence of pyrite and compacted released water karst confirms that bacterial sulfate reduction took place within the weathering crust during the burial stage. The results provide a new perspective for the analysis of the formation of oil-gas reservoir and the exploration of petroleum gas geology resources.
2012, 37(2): 365-369.
doi: 10.3799/dqkx.2012.043
Abstract:
In watershed with occurrence of carbonate minerals, information of carbonate weathering can be easily traced by river chemistry due to its higher weathering rate, whereas signals of silicate weathering tend to be concealed. In this study, temporal and spatial variations of carbon isotope of dissolved inorganic carbon are employed to trace silicate weathering in the Beijiang River, whose watershed is covered by both carbonate and silicate. Water samples were collected from six sites from upstream to downstream for all seasons. Our results show that there is an obvious seasonality in isotope values at sites in the midstream and downstream, displaying marked lighter values in June (-16‰ to -19‰) except for the upstream sites showing less varying carbon isotope values. Taking into consideration of constrains of various processes on dissolved inorganic carbon isotope, we propose that silicate weathering is greatly enhanced in summer in addition to carbonate weathering, which strengthens carbon sink significantly.
In watershed with occurrence of carbonate minerals, information of carbonate weathering can be easily traced by river chemistry due to its higher weathering rate, whereas signals of silicate weathering tend to be concealed. In this study, temporal and spatial variations of carbon isotope of dissolved inorganic carbon are employed to trace silicate weathering in the Beijiang River, whose watershed is covered by both carbonate and silicate. Water samples were collected from six sites from upstream to downstream for all seasons. Our results show that there is an obvious seasonality in isotope values at sites in the midstream and downstream, displaying marked lighter values in June (-16‰ to -19‰) except for the upstream sites showing less varying carbon isotope values. Taking into consideration of constrains of various processes on dissolved inorganic carbon isotope, we propose that silicate weathering is greatly enhanced in summer in addition to carbonate weathering, which strengthens carbon sink significantly.
2012, 37(2): 370-374.
doi: 10.3799/dqkx.2012.044
Abstract:
Groundwater model is set up to calculate ecological water requirements in Baoding, Hebei Province. Modeling results show that a total of 6.4×107 m3 groundwater is consumed annually under current situation which leads to continual decline of groundwater level. Modeling scheme is designed considering reducing groundwater yield and restoring water body of Baiyangdian to that of 1975. The results show that it is possible to restore water body of Baiyangdian to that of 1975 with an annual groundwater supplement of about 8.0×107 m3 while reducing groundwater yield by 1.47×108 m3. The groundwater level reaches ecological level. Ecological water requirements is about 1.5×109 m3. This study is of importance to groundwater eco-environment restoration in semi-humid area and semi-arid area.
Groundwater model is set up to calculate ecological water requirements in Baoding, Hebei Province. Modeling results show that a total of 6.4×107 m3 groundwater is consumed annually under current situation which leads to continual decline of groundwater level. Modeling scheme is designed considering reducing groundwater yield and restoring water body of Baiyangdian to that of 1975. The results show that it is possible to restore water body of Baiyangdian to that of 1975 with an annual groundwater supplement of about 8.0×107 m3 while reducing groundwater yield by 1.47×108 m3. The groundwater level reaches ecological level. Ecological water requirements is about 1.5×109 m3. This study is of importance to groundwater eco-environment restoration in semi-humid area and semi-arid area.
2012, 37(2): 375-380.
doi: 10.3799/dqkx.2012.045
Abstract:
Evapotranspiration is an important component of both energy balance and hydrological budget. It also plays a major role in both assessment and analysis of water resources and global climate change. Accurate estimation the evapotranspiration is a key issue in hydrological study field. Based on the surface energy balance system, the surface reflection of MOD09 and land surface temperature, emissivity of MOD11 was used to estimate the evapotranspiration of Hailiutu River basin, combined with the observed meteorological and hydrological data. The results indicate that the annual evapotranspiration of Hailiutu River basin in 2008 is 324.94 mm, which is validated by water budget.
Evapotranspiration is an important component of both energy balance and hydrological budget. It also plays a major role in both assessment and analysis of water resources and global climate change. Accurate estimation the evapotranspiration is a key issue in hydrological study field. Based on the surface energy balance system, the surface reflection of MOD09 and land surface temperature, emissivity of MOD11 was used to estimate the evapotranspiration of Hailiutu River basin, combined with the observed meteorological and hydrological data. The results indicate that the annual evapotranspiration of Hailiutu River basin in 2008 is 324.94 mm, which is validated by water budget.
2012, 37(2): 381-390.
doi: 10.3799/dqkx.2012.046
Abstract:
In order to better understand the occurrence of high arsenic groundwater, rare earth elements (REEs) analyses were conducted for groundwater from the Datong basin. The results indicate that high arsenic groundwater usually has low ∑REE concentration and enriches in HREEs relative to LREEs. The low concentration of ∑REE in groundwater samples could be due to the scavenging of REEs onto the surface of solid phase Fe-Mn oxides/hydroxides within aquifer sediment. The enrichment of HREEs can be attributed to the combined result of complexation, and desorption and readsorption. The average up crust normalized REEs patterns clearly exhibit significant positive Ce and Eu anomalies in high arsenic groundwater. The observed good correlation between Ce/Ce* values and Eu and Fe+Mn could be related to the reductive dissolution of Fe and Mn oxides/hydroxides. The relationship between As and Ce/Ce* value and Eu suggests that Ce/Ce* value and Eu concentration are useful indicators of arsenic mobilization in groundwater system.
In order to better understand the occurrence of high arsenic groundwater, rare earth elements (REEs) analyses were conducted for groundwater from the Datong basin. The results indicate that high arsenic groundwater usually has low ∑REE concentration and enriches in HREEs relative to LREEs. The low concentration of ∑REE in groundwater samples could be due to the scavenging of REEs onto the surface of solid phase Fe-Mn oxides/hydroxides within aquifer sediment. The enrichment of HREEs can be attributed to the combined result of complexation, and desorption and readsorption. The average up crust normalized REEs patterns clearly exhibit significant positive Ce and Eu anomalies in high arsenic groundwater. The observed good correlation between Ce/Ce* values and Eu and Fe+Mn could be related to the reductive dissolution of Fe and Mn oxides/hydroxides. The relationship between As and Ce/Ce* value and Eu suggests that Ce/Ce* value and Eu concentration are useful indicators of arsenic mobilization in groundwater system.
