Hydrogeochemical characteristics of central Jianghan Plain, China

The central Jianghan Plain is the semi-closed basin in the middle reaches of Yangtze River. A total of 78 water samples targeting groundwater were collected from 75 sites in this study site, the area between Yangtze River and Han River, including rivers and lakes for temperature, pH, electrical conductivity (EC), total dissolved solids (TDS) and ion composition measurements. Correlation matrix was used to assess the geochemical and anthropogenic processes. The most confined groundwater was grouped into HCO₃–Ca–Mg, while phreatic groundwater and surface water had a more diversified hydrochemistry. The spatial variation in overall water quality as well as comparison with WHO (World Health Organization) standards for drinking water is illustrated. Mn, As and NO₃ ^? concentrations were found to exceed the allowable limits for drinking water of WHO guidelines, and they also show remarkable spatial variations. Abnormally high nitrate concentration, up to 150–190 mg/l, was found only in phreatic groundwater, which suggested that the nitrate pollution might be caused by agricultural activities. The present study may be helpful in further studies concerning water quality issues in this area where groundwater is a vital source for drinking and other activities.     

Physico-chemical analysis of surface and groundwater around Singrauli Coal Field, District Singrauli, Madhya Pradesh, India

The present study was carried out in Singrauli area of the north India to know the water quality at selected sites. Physico-chemical parameters like pH, total dissolved solids (TDS), bicarbonate, hardness, calcium, magnesium, sodium, potassium, chloride, sulfate, copper, iron, cobalt, manganese, zinc, and chromium were analyzed in 27 water samples. Locations selected for sampling were based on the preliminary field survey carried out to understand the overall impact of mining and industrialization on the surface and groundwater resources of Singrauli. Base map, drainage map, and land use/land cover of the study area were prepared from Survey of India topographic map 63 L/12 on 1:50000 scale and satellite data of IRS P6 LISS III 4th May 2010. Land use were categorized into 15 categories out of which major area occupied by open forest covers 20.33 %, uncultivated land 20.25 %, cultivated land 12.60 %, dense forest 11.00 %, and other categories cover 35.82 %. The results obtained are compared with World Health Organisation standards for drinking water quality. The physico chemical analysis shows alkaline nature of water, soft to moderately soft, TDS and total alkalinity exceeds the desirable limit. The major ions in water like calcium, and magnesium are within desirable limits, and sulfate and potassium exceed in limit at some locations, whereas sodium and chloride show higher values. The minor ions like copper and zinc show values within desirable limits whereas iron, cobalt, and chromium show higher values than the desirable limits which deteriorate the quality of water.     

An integrated approach for assessment of groundwater quality in and around uranium mineralized zone,Gogi region,Karnataka, India

Assessment of groundwater quality is an important aspect of water security, which is the key to ensure sustainable development. The objective of the study is to bring out an integrated approach for assessment of groundwater quality for drinking and irrigation purposes. Gogi region, Karnataka, India was chosen as the study area due to the effect of the presence of medium-grade uranium deposits. An integrated approach including the concentration of major ions, trace elements and uranium was employed to investigate the quality of groundwater. Totally, 367 groundwater samples were collected periodically from 52 wells distributes over the Gogi region and the parameters such as pH, electrical conductivity, total dissolved solids (TDS), Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl^?, SO₄ ^2?, NO₃ ^?, Zn, Pb, Cu, and uranium of groundwater were analysed. Spatial distribution maps of various chemical constituents were prepared using geographic information system and its temporal variation was plotted in box and whisker plot. The analytical data were compared with Bureau of Indian Standards and World Health Organisation standards to determine drinking water quality and parameters such as salinity hazard, alkalinity hazard and percent sodium were estimated to assess the irrigation quality. Multivariate statistical analysis by cluster analysis was also performed which results in two groups consisting of wells with unsuitable water for drinking purposes. Groundwater in about 15% of the sampling wells were found to be unsuitable for domestic purpose based on TDS and about 17% were unsuitable based on uranium concentration. Finally, integration of spatial variation in TDS and uranium reveals that about 25% of the wells were unsuitable for domestic purposes. It is suggested that such an integrated approach needs to be formulated considering major ions, trace elements and radioactive elements for proper assessment of water quality. Implementation of managed aquifer recharge structures in the study area is suggested since it would potentially reduce the concentration of ions.     

Evaluation of groundwater quality for irrigation and drinking using GIS and geostatistics in a peri-urban area of Delhi, India

Intensive agriculture by indiscriminate use of agrochemicals, sewage water, and polluted drain water has posed a serious threat to groundwater quality in some peri-urban areas of Delhi like Najafgarh block. The objective of the study was to determine the groundwater quality and to map their spatial variation in terms of suitability for irrigation and drinking purpose. Ordinary kriging method was used for preparation of thematic maps of groundwater quality parameters such as electrical conductivity, sodium adsorption ratio, bicarbonate, magnesium/calcium ratio, total dissolved solids, chloride, nitrate and hardness. Exponential semivariogram model was best fitted for all quality parameters except chloride and hardness, where spherical model fitted best. Pollution level was highest at south and south-eastern part of the study area. Better quality groundwater may be expected at the northern and western part. High salinity was due to high chloride concentration in the groundwater. Nitrate pollution level was found to be very alarming and need immediate interventions. High dissolved solids and hardness made the groundwater unsuitable for drinking. There were negligible sodium and bicarbonate hazard in the study area. The groundwater quality index was devised to analyse the combined impact of different quality parameters on irrigation and drinking purposes. The irrigation water quality index and drinking water quality index distribution maps delineated an area of 47.29 and 6.54 km² suitable for irrigation and drinking, respectively. These safe zones were found as a small strip along the northern boundary and a very small pocket at the western side of the study area.     

The influence of irrigation and Wuliangsuhai Lake on groundwater quality in eastern Hetao Basin,Inner Mongolia,China

Geochemical and isotopic characterization of groundwater and lake-water samples were combined with water and total dissolved solids balances to evaluate sources of groundwater quality deterioration in eastern Hetao Basin, Inner Mongolia, China. Groundwater quality is poor; 11 of 13 wells exceed drinking-water guidelines for at least one health-based parameter and all wells exceed aesthetic guidelines. The well water is largely derived from Yellow River irrigation water. Notably high uranium concentrations in the Yellow River, relative to world rivers, suggest groundwater uranium and other trace elements may originate in the river-derived irrigation water. Complex hydrostratigraphy and spatial variation in groundwater recharge result in spatially complex groundwater flow and geochemistry. Evapotranspiration of irrigation water causes chloride concentration increases of up to two orders of magnitude in the basin, notably in shallow groundwater around Wuliangsuhai Lake. In addition to evapotranspiration, groundwater quality is affected by mineral precipitation and dissolution, silicate weathering, and redox processes. The lake-water and TDS balances suggest that a small amount of discharge to groundwater (but associated with very high solute concentrations) contributes to groundwater salinization in this region. Increasing salinity in the groundwater and Wuliangsuhai Lake will continue to deteriorate water quality unless irrigation management practices improve.     

Evaluation of groundwater resources for drinking and agricultural purposes, Abar Al Mashi area, south Al Madinah Al Munawarah City, Saudi Arabia

A hydrogeochemical study was conducted on the groundwater of south Al Madinah Al Munawarah City, Saudi Arabia, to assess the quality of groundwater for drinking and irrigation uses. Groundwater samples have been collected and analyzed for major and some trace constituents from the study area. The nitrate concentration in most groundwater samples of the study area exceeded the safe limits for drinking purposes, whereas the concentrations of phosphate, boron, and trace constituents were below the maximum permissible limit for drinking purposes; Cr in two samples showed high content over the recommended limits of drinking purposes. Uncontrolled abstraction of groundwater in Abar Al Mashi area caused many environmental problems including water resource depletion and contamination. Correlations between chloride and major ions were positive and may be attributed to impact of agricultural activities on groundwater chemistry. Groundwater of the study area was classified into six water types. The chemical water types of groundwater in the study area contain CaHCO₃ in the eastern and southeastern parts and NaCl in western and northwestern parts, reflecting different land use characteristics and pollution sources. Piper diagram showed that almost all the samples fall in one zone, indicating similar chemical signature. Groundwater can be used safely for drinking with special treatments to eliminate the effect of increased concentrations of total dissolved solids, nitrate, and chromium. The groundwater of the study area can be used safely for irrigation on clay soil; however, specific crops should be selected according to their salt tolerance.     

Hydrochemical characteristics and the effects of irrigation on groundwater quality in Harran Plain,GAP Project,Turkey

Improper design, faulty planning, mismanagement and incorrect operation of irrigation schemes are the principle reasons for the deterioration of groundwater quality in a large number of countries, in particular in semi-arid and arid regions. The aim of this study is to determine the dimensions of groundwater quality after surface irrigation was begun in the semi-arid Harran Plain. Physical and chemical parameters of the groundwater including pH, temperature, electrical conductivity (EC), sodium, potassium, calcium, magnesium, chloride, bicarbonate, sulphate, nitrate, nitrite, ammonium, total phosphorus, total organic carbon and turbidity were determined monthly during the 2006 water year. The quality of the groundwater in the study area was assessed hydrochemically in order to determine its suitability for human consumption and agricultural purposes. In the general plain, the EC values measured were considerably above the guide level of 650 μS/cm, while nitrate in particular was found in almost all groundwater samples to be significantly above the maximum admissible concentration of 50 mg/l for the quality of water intended for human consumption as per the international and national standards. Total hardness reveals that a majority of the groundwater samples fall in the very hard water category. Interpretation of analytical data shows that Ca–HCO₃ and Ca–SO₄ are the dominant hydrochemical facies in the study area.     

Geographic Information System and groundwater quality mapping in Panvel Basin,Maharashtra, India

Panvel Basin of Raigarh district, Maharashtra, India is the study area for groundwater quality mapping using the Geographic Information System (GIS). The study area is typically covered by Deccan basaltic rock types of Cretaceous to Eocene age. Though the basin receives heavy rainfall, it frequently faces water scarcity problems as well as water quality problems in some specific areas. Hence, a GIS based groundwater quality mapping has been carried out in the region with the help of data generated from chemical analysis of water samples collected from the basin. Groundwater samples show quality exceedence in terms of chloride, hardness, TDS and salinity. These parameters indicate the level of quality of groundwater for drinking and irrigation purposes. Idrisi 32 GIS software was used for generation of various thematic maps and for spatial analysis and integration to produce the final groundwater quality map. The groundwater quality map shows fragments pictorially representing groundwater zones that are desirable and undesirable for drinking and irrigation purposes.     

Health risk assessment of fluoride with other parameters in ground water of Sikar city (India)

Geochemical processes are identified as controlling factors of groundwater chemistry, including chemical leaching and fluoride contaminations. These geochemical processes are identified using characterization of the major physico-chemical parameters of ground water from northern part of Sikar city. For this purpose, 15 ground water samples have collected and analyzed for different water quality parameters, such as pH, EC, TDS, TH, TA, DO, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, nitrate, sulfate and fluoride with the help of standard methods recommended by American Public Health Association. The analysis indicated that fluoride concentrations in four samples are at alarming state as compared to the World Health Organization standards for drinking purposes, thereby suggesting the need for treatment and precautionary measures for use of the particular ground water. The increased fluoride level in the ground water of Sikar city is due to the some geological process such as dissolution of fluoride rich mineral (fluorspar) in the favorable environment. To classify the ground water ability for different purposes various graphical plots like Piper tri-linear, Durov, Schoeller, Bar, Scatter diagrams have been drawn. On the basis of physico-chemical, graphical and statistical analysis (Spearman’s Rank correlations), various dimension of improving water quality for drinking purposes have also been suggested.     

江苏泗阳城区浅层地下水化学特征及其影响因素

根据现场取样分析,对江苏泗阳城区浅层地下水水文地质特征、水化学组分在空间上的分布特征进行了研究,并对其形成特点和影响因素进行探讨。结果表明：研究区浅层地下水水化学类型呈现明显的平面分带性,京杭运河西南侧浅层地下水阴离子中HCO^-₃占主导地位,溶解性总固体(TDS)多小于1 g/L,总硬度小于450 mg/L,水质一般较好;京杭运河东北侧浅层地下水阴离子以HCO^-₃、Cl^-、SO^2-₄为主,TDS多介于1~3 g/L,总硬度大于450 mg/L,为微咸水,水质变差。研究区NH⁺₄-N、NO^-₃-N污染较明显,空间分布具有明显的地域性差异;高浓度分布在京杭运河两岸以及泗阳农场一带,纵向上NH⁺₄-N高浓度主要集中在小于18 m的浅层地下水,NO^-₃-N多在8~20 m的浅层地下水富集。研究区浅层地下水水化学组分现状特征及其差异性的形成与演化,受海陆交互相沉积环境、含水介质、地下水补径条件以及人类活动等因素的影响。     

神府矿区地下水环境背景值初步研究

神府矿区存在煤矿及煤化工生产过程中污染物排放引发的污染问题。结合以往资料,本次研究在神府矿区共采集地下水样品75组,进行了详细的地下水污染调查评价。本文选择数理统计方法,对神府矿区地下水水质指标TDS、TH、Cl-、SO42-、Fe、Mn、NO3-环境背景值进行研究。结果显示：地下水化学元素多以对数正态分布和偏态分布为主,认为地貌单元、水动力条件等因素对研究区浅层地下水指标的空间分布起主要控制作用。     

西北地区地下水质量评价

本文以地下水调查的水质分析资料和动态监测资料为基础,参照我国地下水质量标准和生活饮用水卫生标准,对西北地区地下水质量状况进行综合评价。结果表明西北地区地下水质量状况为全国较差的地区,不可直接利用的地下水多分布于该区内陆盆地中心地带;地下水污染多发生在主要城市、工矿企业及其周边地区,水污染主要呈点状、线状分布,主要超标项目为溶解性总固体、总硬度、硝酸盐、亚硝酸盐、硫酸盐、氯化物和氟化物等。     

Groundwater quality assessment for drinking purpose in Raipur city,Chhattisgarh using water quality index and geographic information system

An effort has been made to comprehend the groundwater quality of Raipur city for drinking purpose utilizing Water Quality Index (WQI) and Geographic Information System (GIS) techniques. In this study thirty four groundwater samples were collected during May, 2015. Standard methods has been adopted in groundwater sampling which are prescribed by the American Public Health Association (APHA, 1995). Eight water quality parameters have been considered to ascertained water quality index viz. pH, chloride, fluoride, calcium, magnesium, alkalinity, hardness and nitrate. The Bureau of Indian Standard (BIS, 2009) has been considered to assess the suitability of groundwater for drinking purposes and for the calculation of WQI. This study reveals that 76% area is falling under excellent, very good and good category and 24% area is falling under poor, very poor and unfit category as per the WQI classification. The predicted accuracy of the obtained result is around 97.05% reflecting capability of adopted techniques. Anthropogenic activities are influencing the groundwater quality of the study area. The present study is helpful in proper planning and management of available water resource for drinking purpose.     

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.     

Nitrate contamination in groundwater of Sopore town and its environs,Kashmir, India

An attempt has been made in this research work to evaluate the concentration of nitrate in groundwater and its management in Apple town and its environs. Groundwater pollution has been reported in many aquifers because of high concentration of nitrate in ground water, which is the result of excessive use of fertilizers to cropland. Systematic sampling was done, with a view to understand the source of nitrate concentration in the study area. Fifteen sample sites were selected and the samples were taken for a baseline study to understand the geochemistry of the study area and to assess its physicochemical characteristics. The water quality parameters were investigated for summer (May, 2007) and winter (December, 2007) seasons and were compared with the standard values given by ICMR / WHO. The hydrochemical data of 15 samples indicates that the concentration of almost all parameters fall within the permissible limits except nitrate. Linear Trend Analysis on seasonal and annual basis clearly depicted that nitrate pollution in the study area is increasing significantly. About 85% of samples during summer season and 67% of the samples during winter season were showing a high concentration of nitrate, exceeding permissible limit of WHO (50 mg/l), which is due to the use of nitrogenous fertilizers in the study area. Appropriate methods for improving the water quality and its management in the affected areas have been suggested.     

Groundwater quality assessment using WQI and GIS techniques, Dindigul district, Tamil Nadu, India

The quality of groundwater was assessed by determining the physicochemical parameters (pH, EC, TDS and TH) and major ions concentration (HCO₃, Cl, FSO₄, Ca, Mg, Na and K) around Dindigul district, Tamil Nadu, India. The groundwater samples were collected from 59 bore wells covering the entire study area and analyzed using standard methods. The GIS mapping technique were adopted to highlight the spatial distribution pattern of physicochemical parameters and major ion concentration in the groundwater. Gibbs diagram reveals that the source of major ions is predominantly derived from rock–water interaction and evaporation dominance process. The salt combinations of the aquifers are dominated by CaHCO₃, mixed CaMgCl, mixed CaMgHCO₃ and CaCl facies type due to leaching and dissolution process of weathered rocks. The Canadian Council of Ministers of Environment Water Quality Index (CCMEWQI) suggests that most of the groundwater quality falls under good to marginal category. The statistical analysis indicates that the presence of major ions and physicochemical parameters are chiefly controlled by rock–water interaction and residence time of the groundwater. However, the major nutrient like nitrite in the groundwater probably comes from anthropogenic process. Based on the groundwater quality standards, majority of the samples are suitable for drinking purposes except few in the study area.     

Geochemical characterization of groundwater from northeastern part of Nagpur urban,Central India

Hydrogeochemical investigations are carried out in the northeastern part of Nagpur urban to assess the quality of groundwater for its suitability for drinking and irrigation purposes. Groundwater samples are collected from both shallow and deep aquifers to monitor the hydrochemistry of various ions. The groundwater quality of the area is adversely affected by urbanization as indicated by distribution of EC and nitrate. In the groundwater of study area, Ca²⁺ is the most dominant cation and Cl⁻ and HCO₃ ⁻ are the dominant anions. Majority of the samples have total dissolved solids values above desirable limit and most of them belong to very hard type. As compared to deep aquifers, shallow aquifer groundwaters are more polluted and have high concentration of NO₃ ⁻. The analytical results reveal that most of the samples containing high nitrate also have high chloride. Major hydrochemical facies were identified using Piper trilinear diagram. Alkaline earth exceeds alkalis and weak acids exceed strong acids. Shoeller index values reveal that base-exchange reaction exists all over the area. Based on US salinity diagram most of samples belong to high salinity-low sodium type. A comparison of groundwater quality in relation to drinking water standards showed that most of the water samples are not suitable for drinking purpose.     

Assessment of nitrate contamination of Lidder catchment Kashmir, India

Nitrate contamination in the groundwater from various sources is one of the major problems of water resources in Liddercatchment, Kashmir. Systematic sampling was carried out during summer 2007, with a view to understand the source of nitrate ions in the groundwater of the Lidder catchment. Twelve sample sites were selected and samples were taken for a baseline study to understand the geochemistry of the groundwater and to assess the overall physico-chemical characteristics. Results showed that NO ₃ ^? concentration in ranged from 18.72?mg/L to 75.93?mg/L with an average of 47.03?mg/L. More than 80% (83.33%) of the samples collected from various sampling stations had nitrate concentrations exceeding the threshold value of 20?mg/L, and 58.33% of the samples collected had nitrate concentrations higher than 50?mg/L, the maximum acceptable nitrate concentration for drinking water. There is a wide spatial variation in the nitrate concentration in the groundwater. Monitoring the water quality of various sampling stations showed that the lowest concentrations of nitrate were found in the wet season (January, February, and December), while the highest concentrations were found in the dry season (August, September). Numerous human perturbations have been detected affecting the water quality of Lidder catchment. Disposal of sewage and animal wastes was found to contribute about 85% of total nitrate pollution in the study area. Based on the trend analysis (using previous data), future scenario of nitrate pollution has been predicted in the study area. The results of this study are useful to highlight one of the most important environmental problems, namely the degradation of the water quality, and may serve to alert and encourage local and national authorities to take substantial steps and actions to protect and manage water quality.     

Hydrochemistry of groundwater and its assessment for irrigation purpose in coastal Jeffara Aquifer, southeastern Tunisia

Groundwater is of a paramount importance in arid areas, as it represents the main water resource to satisfy the different needs of the various sectors. Nevertheless, coastal aquifers are generally subjected to seawater intrusion and groundwater quality degradation. In this study, the groundwater quality of the coastal Jeffara aquifer (southeastern Tunisia) is evaluated to check its suitability for irrigation purposes. A total of 74 groundwater samples were collected and analyzed for various physical and chemical parameters, such as, electrical conductivity, pH, dissolved solids (TDS), Na, K, Ca, Mg, Cl, HCO₃, and SO₄. Sodium adsorption ratio, magnesium adsorption ratio, Sodium percentage, and permeability index were calculated based on the analytical results. The analytical results obtained show a strong mineralization of the water in the studied aquifer. TDS concentrations range from 3.40 to 18.84 g?L^?1. Groundwater salinity was shown to be mainly controlled by sodium and chloride. The dominant hydrochemical facieses are Na–Cl–Ca–SO₄, mainly as a result of mineral dissolution (halite and gypsum), infiltration of saline surface water, and seawater intrusion. Assessment of the groundwater quality of the different samples by various methods indicated that only 7% of the water, in the northwest of the study area, is considered suitable for irrigation purposes while 93% are characterized by fair to poor quality, and are therefore just suitable or unsuitable for irrigation purposes.     

Soil and groundwater quality with reference to nitrate in a semiarid agricultural region

Nitrate is a common pollutant in surface water and groundwater of agricultural areas. It is essential to monitor this pollutant in groundwater, especially when it is used for drinking purposes without treatment. The present study was carried out in an intensively irrigated area which forms a part of Nalgonda district, Andhra Pradesh, India where groundwater meets all the water needs of the rural population living in this area. The objective was to assess the spatiotemporal variation in the concentration of nitrate in groundwater and soil. Based on the analysis of 496 groundwater samples collected from 45 wells over a period of 2 years from March 2008 to January 2010 by sampling every 2 months, it was observed that groundwater in 242 km² of the total 724 km² area had nitrate above the maximum permissible limit of 45 mg/l for drinking purposes. Nitrate concentration in groundwater showed a positive relation with potassium, chloride, and sulfate, indicating their source from fertilizers. Reasons for the high concentration of nitrate in domestic areas were the dumping of animal wastes and leakage from septic tanks. The pH of the soil samples showed that most of the area had basic soil. Apart from pH, organic carbon, available phosphorous, available potassium, ammoniacal nitrogen, and nitrate nitrogen were also analyzed in the 97 soil samples.