Impact of coal gangue on the level of main trace elements in the shallow groundwater of a mine reclamation area

Coal gangue is the most used filling material during reclamation of areas suffering subsidence from min- ing. Main trace element levels (F, As, Hg, and Pb) in shallow groundwater in the reclamation area may be affected by leaching from the gangue. This can has an impact on the application of the water for agricul- tural irrigation or use as drinking water. Therefore, it is of great significance to understand the effect coal gangue has on the shallow groundwater of a reclaimed area. We studied the effect of coal gangue on fluo- rine, arsenic, mercury, and lead levels in the shallow groundwater of a reclamation area by testing the water and the coal gangue. One well near the reclamation area was used as a control well and element levels in water from this well and from the soil next to the well were also measured. The results show that the levels of these elements are increasing in the reclamation area over time. The increase in fluorine, arsenic, mercury, and lead in monitor wells varies from 7.42% to 8.26%, from 7.13% to 7.90%, from 4.85% to 6.48%, and from 4.69% to 6.42%, respectively. Fluorine and arsenic levels are lower in monitor wells than in the control water. The other elements are found in greater concentration than in the control. The Nemerow index also indicates that the shallow groundwater in the reclamation area I is moderately affected by the back-filling coal gangue, while the shallow groundwater in the reclamation area II and III are slightly affected by the back-filling coal gangue. This shallow groundwater could be used for agri- cultural irrigation or for drinking.

Geochemical Characters of Water Coproduced with Coalbed Gas and Shallow Groundwater in Liulin Coalfield of China

To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,total dissolved solids （TDS）,total hardness,and concentrations of metasilicic acid,sodium and kalium,calcium ion,magnesium ion,ammonium iron,bicarbonate ion,carbonate,chloride,sulfate ion,nitrate ion,fluoride,lithium,zinc,nickel,manganese,iron,boron,barium,etc.of the samples were measured.Research results showed the following：（1） Concentrations of TDS,chloride,fluoride,sodium and kalium,ammonium,iron,and barium in the water coproduced with coalbed gas exceeded the national standards of China; however,physical,chemical,and biological properties of shallow groundwater could meet the national standard.（2） The water produced from coalbed contained mainly Na-Cl·HCO3,with average TDS of 4588.5 ppm,whereas shallow groundwater contained a mixture of chemicals including Na.Mg.Ca-HCO3·SO4 and Na.Mg-HCO3·SO4,with average TDS of 663.8 ppm.（3） In general,it was observed that bicarbonate and sodium accumulated in a reducing environment and deeper system,while depletion of hydrogen ions and dissolution of sulfate,calcium,and magnesium occurred in a redox environment and shallow system.（4） Sodium and kalium,ammonium,chloride,and bicarbonate ions were the main ions found in the study area.

Hydrochemical characteristics and water quality evaluation of shallow groundwater in Suxian mining area,Huaibei coalfield,China

The aim of this study is to evaluate the hydrogeochemical characteristics and water environmental quality of shallow groundwater in the Suxian mining area of Huaibei coalfield,China.The natural formation process of shallow groundwater in Suxian is explored using Piper trilinear charts and Gibbs diagrams,and by examining the ratios between the major ions.United States Salinity Laboratory(USSL)charts,Wilcox diagrams,and the water quality index(WQI)are further employed to quantify the differences in water quality.The results reveal that the main hydrochemical facies of groundwater are HC03-Ca,and that silicate dissolution is the main factor controlling the ion content in shallow groundwater.The USSL charts and Wilcox diagrams show that most of the water samples would be acceptable for use in irrigation systems.The WQI results for each water sample are compared and analyzed,and the quality of groundwater samples around collapse ponds is found to be relatively poor.

Analysis on the Chemical Characteristics of Shallow Groundwater and Causes of Formation in the Area around Poyang Lake

[Objective] The study aimed at analysing the chemical characteristics of shallow groundwater and causes of formation around Poyang Lake area. [Method] The quality of shallow groundwater under seven counties or cities around Poyang Lake was investigated in 2010, and compared different regions from salinity, hardness, conductivity, hydrochemistry types and so forth, so as to reveal the status quo, change characteristics and reasons of shallow groundwater. [Result] Except for pH, other water quality indicators of shallow groundwater around Poyang Lake were better, attaining Class I water quality standards. Among these regions, the salinity, hardness, conductivity, Na+, K+, Ca2+, Mg2+, Cl- and HCO-3 concentration of shallow groundwater in Nanchang city were up to the maximum values, while pH and SO2-4 concentration were the highest in Duchang County; Mg2+ concentration and pH were the lowest in Poyang County, and hardness, K+, Ca2+, SO2-4 and Cl- concentration in Yongxiu County reached the minimum values, while Na+ concentration, salinity and conductivity were the lowest in Jinxian County. In addition, the better quality of groundwater around Poyang Lake was closely related to the low level of economic development in Jiangxi Province. Meanwhile, many water quality indices in Nanchang City reached the maximum values, and even tended to Class Ⅱ water quality standards, which resulted from the high level of economic development and decisive role of human activities. [Conclusion] The research could provide references for the establishment of management strategies for regional shallow groundwater.

Evaluation of shallow groundwater discharge fluxes and nutrient fluxes in the west of Qinghai Lake using radium isotopes

We collected 14 samples and 9 samples for surface water in Quan bay and the north bay of Qinglai Lake respectively,as well as 11 samples for groundwater and 3 samples for river water.First the water samples were filtered through a

Numerical Modelling of Geochemical Behaviour of Fluoride in the Shallow Groundwater Systems

The Xingtai piedmont plain in Hebei Province is a representative area in northern China where endemic fluorosis is serious and shallow high-F ground water is distributed. In this paper, the area is selected as a typical study area, and on the basis of large amounts of field work and the experiments, through groundwater geochemical modelling and by applying the theory and method of the coupled model of hydrodynamic transport and chemical reactions in a multicomponent system, the author performed numerical modelling of the geochemical behaviour of fluoride in a shallow groundwater system, quantitatively studied the hydrodynamic transport and chemical reaction of fluorine migration, transformation and concentration in a water-heterogeneous unsaturated soil system under the conditions of meteoric water infiltration and quantitatively determined the speciation of fluorine and the saturation state and dissolution/precipitation trend of various solid precipitates in shallow high-F groundwater, thus deepening the understanding of the geochemical behavious of fluorine in shallow groundwater and revealing the essence of some environmental problems at a higher level.

Analysis of Cropping Practices on Two Irrigated Perimeters of the Volta Blanche Basin with the Use of Shallow Groundwater

This study aims to analyze the development of small-scale irrigation using shallow groundwater in Nahouri province (south-central Burkina Faso). The methodological approach adopted was essentially based firstly on semi-structured surveys with producers who have adopted sump technology and the monitoring of groundwater level using the installed piezometers and secondly on geophysical prospection. Results obtained show that market gardening is mainly a family activity practiced on plots of 0.20 ha with a predominance of pepper cultivation occupying about 75% of cultivated areas. It was also highlighted that this agricultural activity faces several constraints that delay its development. These include: lack of water, land insecurity, small and fragmented farms and difficulty in selling products when they are put on local markets at the very same time as significant price drops. This problem is accentuated by the perishable nature of these market garden products. Despite these limiting factors, there is some satisfaction considering the income earned by farmers, most of whom are able to meet their primary needs. This work made it possible to conclude that even in zones which are not sedimentary formations, it is possible to mobilize groundwater, at a reasonable depth for agricultural purposes, without much effort to practice additional irrigation, knowing that evaporation carries harm to the use of dams.

Regime of subsurface water resources in shallow groundwater agricultural fields

In shallow groundwater agricultural fields, water exchanges between groundwater and soil water happen frequently and intensively. This paper analyzes the regale of subsurface water during the growing period of winter wheat from October 1998 to June 1999 in Yucheng area. During an 8- month period of winter wheat growth. 456.66 mm of evapotranspiration and 75.61mm of groundwater evaporation were measured with a new model lysimeter. Groundwater at 1.60-2.40 m depth of water tables contributed 16.6% of total water used by winter wheat under natural. precipitation and irrigation treatment.The results showed that a significant proportion of field evapotranspiration was supplied by groundwater evaporation, whereas the role of groundwater evaporation was not considered during irrigation, leading to soil water percolation into groundwater.In order to improve water use efficiency of crops, some measures were put forward in the paper. Effective use of groundwater and soil water is a key countermeasure for sustainable development of water-saving agriculture and Water resource exploitation in Yucheng area

Application of Improved Matter-element Extension Method in Comprehensive Assessment of Shallow Groundwater

Taking shallow groundwater in Jinjiang City,Fujian Province for example,it was found that the classical element-matter analysis shows deficiency in calculation of correlation function,so the improved matter-element method was applied for the comprehensive assessment of shallow groundwater in Jinjiang City,and the spatial distribution was shown in maps.The assessment results demonstrated that ground water quality of most regions in the study area belonged to Grade I and II,thus the overall quality of shallow groundwater was good.The groundwater of Grade IV and V(relatively poor and extremely poor) was mainly distributed in Dongshi Town,Chendi Town,Zimao Town,and Shenhu Town,major exceeding-standard factors that influence shallow groundwater quality in the local area included TDS,Mn^(2+),NO_3,NO_2,NH_4^+ and Cl^-,which mainly owed to invasion of seawater,original geological conditions,industrial and agricultural discharge,and human life.

Physicochemical and Microbiological Quality of Shallow Groundwater in Lomé, Togo

The present study aimed to assess the physicochemical and microbiological quality of shallow groundwater tapped by private boreholes for water sale in Togo’s most urbanized coastal areas. Ninety-six (96) groundwater samples were collected at the water sale points for chemical and microbiological analyses using standard methods. The results showed that groundwater is predominantly acidic with fresh and brackish water of Na-Cl type. High concentrations of dissolved inorganic nitrogen (NO3- , NH4+and NO2-) and permanganate indices indicating potential organic matter were found. Among the major ions, Na+ (46.9%), Cl- (51.0%) and NO3- (50.0%) present the highest percentages of unsuitable concentrations compared to WHO guidelines. These findings indicate the control of the natural impact of seawater and lagoon system and anthropogenic pollution from domestic and urban wastes on groundwater’s physicochemical quality. About 65% of groundwater samples did not comply with the drinking water guidelines for microbial indicators, including total mesophilic flora, thermotolerant coliforms, and sulfite-reducing anaerobes. The results showed the failure of sanitation and hygiene conditions around sampling points and fecal contamination from sewage, pit latrines, septic tanks, and refuse and waste disposal. The degradation of physicochemical quality is higher in the old and high-density built-up areas. Simultaneously, microbial contamination represents a high risk of contracting waterborne or hygiene-sanitation-related diseases in the whole study area. This study provides a global view of shallow groundwater’s physicochemical and microbiological quality in the study area. Limitations and suggestions for future research are discussed.

Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China,2004-2010

The nitrate-nitrogen（NO 3-N） concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations,representing typical agroand forest ecosystems,were assessed using monitoring data collected between 2004 and 2010.Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater,and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made.Results indicated that most of the NO 3--N concentrations in groundwater from the agroand forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard：Quality Standard for Ground Water（≤ 20 mg/L）.Over the study period,the average NO 3--N concentrations were significantly higher in agro-ecosystems（4.1 ± 0.33 mg/L） than in forest ecosystems（0.5 ± 0.04 mg/L）.NO 3-N concentrations were relatively higher（〉 10 mg N /L） in 10 of the 43 wells sampled in the agricultural ecosystems.These elevated concentrations occurred mainly in the Ansai,Yucheng,Linze,Fukang,Akesu,and Cele field sites,which were located in arid and semiarid areas where irrigation rates are high.We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.

Estimating the effect of shallow groundwater on diurnal heat transport in a vadose zone

The influence of shallow groundwater on the diurnal heat transport of the soil profile was analyzed using a soil sensor automatic monitoring system that continu- ously measures temperature and water content of soil profiles to simulate heat transport based on the Philip and de Vries （PDV） model. Three experiments were conducted to measure soil properties at depths of 5 cm, 10 cm, 20 cm, and 30 cm when groundwater tables reached l0 cm, 30 cm, and 60 cm （Experiments I, II, and III）. Results show that both the soil temperature near shallow groundwater and the soil water content were effectively simulated by the PDV model. The root mean square errors of the temperature at depths of 5 cm, 10 cm, and 20 cm were 1.018℃, 0.909℃, and 0.255℃, respectively. The total heat flux generated the convergent and divergent planes in space-time fields with valley values of-161.5 W-m 2 at 7：30 and -234.6 W.m2 at 11：10 in Experiments II and III, respectively. The diurnal heat transport of the saturated soil occurred in five stages, while that of saturated-unsaturated and unsaturated soil profiles occurred in four stages because high moisture content led to high thermal conductivity, which hastened the heat transport.

Analysis on hydrochemical characteristics of groundwater in strongly exploited area in Hutuo River Plain

The Hutuo River alluvial-proluvial fan is located in North China Plain, and groundwater is the main source of water supply for agriculture and domestic water. Shijiazhuang depression funnels due to the long-term excessive exploitation are the bottleneck of the regional economic development. Analyzing the chemical characteristics of groundwater under the condition of strong human activities, can provide a scientific basis for further study of strong groundwater mining area environmental change. 143 groups of shallow groundwater samples are collected during the period of 2007-2008. In this paper, the hydrochemical characteristics of groundwater in the Hutuo River Plain area are analyzed systematically, using hydrogeochemical theory, combined with statistical methods and hydrochemical methods. Results are shown as follows: HCO_3^- and Ca^(2+) are major anion and cation. The variation coefficients of K^+, Ca^(2+), Mg^(2+) and HCO_3^- between 0.25 and 0.52, which means small and stable relatively. The variation coefficient of are Na^+, NO_3^-, Cl-, SO2-4 were large(0.89-1.01). They are sensitive and vulnerable to environmental change affect. Due to the impact of human activities, from the top to the edge of the alluvial-proluvial fan, the hydrochemical types of groundwater change from single to multiple, followed by HCO_3^-Ca·Mg, HCO_3·SO_4-Ca·Mg, HCO_3·SO_4·Cl-Ca·Mg, HCO_3·Cl-Ca·Mg and other types.

The Hydrogeological Consequences of the Proposed Extraction of the Deep Groundwater in Jordan

Many officials and planners in Jordan have advocated in the last decade extracting the deep brackish, thermal, and salty groundwater resources, desalinate them, and use them for household water supplies. Generally, such groundwater is non-renewable and is found in aquifers underlying fresh renewable groundwater bodies building the base support for them. The deep groundwater feeds the thermal mineralized springs issuing along the eastern escarpment of the Dead Sea-Jordan Rift Valley used for therapeutic purposes. In this article, the geologic set-up of the aquifer series underlying the different parts of the country is outlined to illustrate that all such aquifers extending from ground surface to the impermeable granitic Basement Complex are, in the majority of areas, directly or indirectly interconnected and that extractions from any aquifer, shallow or deep, are effectively taken from the same stock of the groundwater body. Hence, it is concluded that advocating the extraction of the deep salty or brackish groundwater is quasi extracting the same amount of groundwater from the overlying, shallower fresh water aquifers. The deep groundwater issues along the eastern escarpment of the Jordan Rift Valley and is used in household supplies, in irrigation and in spas as curative agent. In addition, the intended use of the deep groundwater to be extracted according to the suggested policy in household supplies requiring desalination, which is a costly unnecessary process accompanied with rigorous environmental ramifications of disposing off the desalination brines.