Assessment of groundwater quality and hydrochemical characteristics in Farashband plain,Iran

Groundwater in Farashband plain, Southern Iran, is the main source of water for domestic and agricultural uses. This study was carried out to assess the overall water quality and identify major variables affecting the groundwater quality in Farashband plain. The hydrochemical study was undertaken by randomly collecting 84 groundwater samples from observation wells located in 13 different stations covering the entire plain in order to assess the quality of the groundwater through analysis of major ions. The water samples were analyzed for various physicochemical attributes. Groundwater is slightly alkaline and largely varies in chemical composition; e.g., electrical conductivity (EC) ranges from 2314 to 12,678 μS/cm. All the samples have total dissolved solid values above the desirable limit and belong to a very hard type. The abundance of the major ions is as follows: Na⁺ > Ca²⁺ > Ma²⁺ > K⁺ and Cl^? > SO₄ ^2– > HCO₃ ^?. Interpretation of analytical data shows three major hydrochemical facies (Ca–Cl, Na–Cl, and mixed Ca–Mg–Cl) in the study area. Salinity, total dissolved solids, total hardness, and sodium percentage (Na%) indicate that most of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standard. A comparison of groundwater quality in relation to drinking water standards showed that most of the water samples are not suitable for drinking purposes. Based on the US salinity diagram, most of samples belong to high salinity and low to very high sodium type.     

Numerical simulation of groundwater flow and contamination transport in Nahavand plain aquifer,west of Iran

Numerical simulation of groundwater flow used for the estimation of hydraulic and hydrologic parameters which is an important tool for the management of aquifers. This study presents the results of a mathematical model developed for the simulation of groundwater flow in Nahavand plain aquifer in the southwest Hamadan province. For this purpose Groundwater Modeling Software (GMS) was used which supports the MODFLOW-2000 code. After gathering required data such as the hydrological, hydrogeological and topography maps, a 3D hydrogeological model of plain was constructed with borehole and surface elevation data. Then MODFLOW was used for simulation of flow. After initial simulation of the flow, the model was calibrated in steady state with trial-and-error and parameter estimation methods the observed head of groundwater table monitoring data of 1997. Results of calibration show that error between observed head and computed head is in allowable range. Also results of computed head with model show that groundwater flow is in the direction of the dominate slope (southeast to northwest). Finally MODPATH code which simulates advective transport of particles was used for estimation of flow path and source of contaminants.     

Groundwater quality assessment in southern parts of Tehran plain,Iran

The hydrochemical characteristics of groundwater in the southern parts of Tehran Province are considered. Twenty-three sampling stations were selected and major anions/cations, electrical conductivity and pH were detected. Sulfate and chloride were found as major anions, while no specific dominant cation was determined. More than half of the samples were found to be unsuitable for drinking purposes, due to high concentrations of anions/cations. Regarding agricultural use, almost all samples were classified as having high-risk levels of salinity, while for alkali hazard considerable risks were observed in most cases. Generally, an increasing trend of salinity is observed from northwest to southeast of the study area. Such increase may be justified by the adjacency of the Iran central desert and salt lake to the southern boundaries of the study area. Extended use of sulfate-containing fertilizers may also play a key role in justifying the high sulfate concentration in comparison to other anions.     

Groundwater quality assessment using the Water Quality Index and GIS in Saveh-Nobaran aquifer,Iran

Groundwater is the most important natural resource used for drinking by many people around the world, especially in arid and semi-arid areas. The resource cannot be optimally used and sustained unless the quality of groundwater is assessed. Saveh-Nobaran aquifer in Iran is the most important groundwater aquiferous system in the region which is considered a major source for drinking and irrigation. The main objective of this study is to understand the groundwater quality status of Saveh-Nobaran aquifer, followed by attempts to investigate the spatial distribution of groundwater quality parameters to identify places with the best quality for drinking consume within the study area. For this purpose, a set of original data, as yet unpublished, is presented. This paper provides an important contribution for understanding relationship between land use and groundwater quality, and also groundwater depth and groundwater quality. This goal has been achieved with the combined use of the Water Quality Index (WQI) and a geographical information system (GIS). A total of 58 groundwater samples were collected and analyzed for major cations and anions. Spatial distribution maps of pH, TDS, EC, TH, Cl, HCO, SO₄, Ca, Mg, Na and K have been created using the kriging method in a GIS environment. From the WQI assessment, over 65 % of the water samples fall within the ‘‘Poor’’, ‘‘Very poor’’ and “unsuitable for drinking” categories, suggesting that groundwater from the center and north-east of the Saveh-Nobaran aquifer is unsuitable for drinking purposes. This research and its results have shown the great combination use of GIS and WQI in assessing groundwater quality. Having a clear view of the geographic areas of groundwater quality, decision makers can plan better for the operation and maintenance of groundwater resources.     

Geochemistry of groundwater from a rhyolite aquifer,Northwest Iran

Chemical data on groundwater composition in rhyolitic hard rock aquifers with limited global occurrence are rarely found. In this research geochemistry of Mahabad Rhyolite Aquifer, NW Iran, was studied considering major ions, silica and trace elements measured in wet and dry seasons. Based on the results, the mean silica content was 18 mg l^?1, less than the average of the rhyolitic waters. However, the relatively higher electrical conductivity (EC) of 418 µS cm^?1 was measured. Based on a PHREEQCI model, the weathering of the silicate minerals and dissolution of carbonated intercalations turns groundwater dominantly into Ca–HCO₃ type, enhancing EC, pH and silica concentration along the flow path. Trace elements of Sr, Ba and Pb were measured at highest concentrations, the later with an average value of 83 ppb exceeds the drinking guidelines. Cluster analysis confirms biotite weathering and barite dissolution as the main sources of the trace elements in the groundwater. The results signify geochemical features of rhyolitic groundwater which can be a useful tracer of mixing in flow systems containing variety of aquifers including rhyolites.     

Hydrogeochemistry and groundwater quality assessment of the multilayered aquifer in Lower Kelantan Basin,Kelantan, Malaysia

Continual expansion of population density, urbanization, agriculture, and industry in most parts of the world has increased the generation of pollution, which contributes to the deterioration of surface water quality. This causes the dependence on groundwater sources for their daily needs to accumulate day by day, which raises concerns about their quality and hydrogeochemistry. This study was carried out to increase understanding of the geological setup and assess the groundwater hydrogeochemical characteristics of the multilayered aquifers in Lower Kelantan Basin. Based on lithological data correlation of exploration wells, the study area can be divided into three main aquifers: shallow, intermediate and deep aquifers. From these three aquifers, 101 groundwater samples were collected and analyzed for various parameters. The results showed that pH values in the shallow, intermediate and deep aquifers were generally acidic to slightly alkaline. The sequences of major cations and anions were Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ and HCO₃^? > Cl^? > SO₄^2? > CO₃^2?, respectively. In the intermediate aquifer, the influence of ancient seawater was the primary factor that contributed to the elevated values of electrical conductivity (EC), Cl^? and total dissolved solids (TDS). The main facies in the shallow aquifer were Ca–HCO₃ and Na–HCO₃ water types. The water types were dominated by Na–Cl and Na–HCO₃ in the intermediate aquifer and by Na–HCO₃ in the deep aquifer. The Gibbs diagram reveals that the majority of groundwater samples belonged to the deep aquifer and fell in the rock dominance zone. Shallow aquifer samples mostly fell in the rainfall zone, suggesting that this aquifer is affected by anthropogenic activities. In contrast, the results suggest that the deep aquifer is heavily influenced by natural processes.     

Arsenic in groundwaters of the alluvial aquifer of Bardsir plain, SE Iran

Bardsir plain is located in the central part of Kerman Province of Iran. The relative prevalence of arsenic-related cancers, the high concentration of arsenic in nearby plains, as well as the recharge of this aquifer through the mountains composed of high-sulfide volcanic rocks have been motivations of the authors to study the concentration of this element in Bardsir plain. Arsenic concentration was measured in 63 groundwater samples using inductively coupled plasma mass spectrometry method. The results were evaluated through iso-concentration maps, correlation diagrams, and multivariate statistical methods. Accordingly, the concentration of arsenic ranges from 1.3 to 464.5 μg/l with an average value of 134.2 μg/l. So, the groundwaters are enriched with arsenic to much higher levels than permitted for than drinking water acceptable level (10 μg/l). The high arsenic levels in groundwaters of Bardsir plain are ascribed to joint influence of decomposition of sulfides present in mountainous volcanic rocks and the mixing with hydrothermal waters in some locations. Supposedly, the prevalence of higher than 8 pH values has enhanced the release of arsenic from Fe-hydroxides generated during sulfide weathering process.     

Hydrogeochemical assessment of groundwater in Isfahan province, Iran

Groundwater quality in five catchment areas in Isfahan province of Iran is assessed by measuring physicochemical parameters including major cation and anion compositions, pH, total dissolved solid, electrical conductivity and total hardness. For this purpose, 567 piezometric well samples were collected in October 2007. The abundance of major ions in four of the catchment areas including Gavkhuni, Ardestan, Salt lake and Central Iran desert basins is similar and follows Cl^??>?SO₄ ^2??>?Na⁺?>?HCO₃ ^??>?Ca²⁺?>?Mg²⁺?>?K⁺?>?CO₃ ^2? trend, while in the fifth basin (Karoon), the trend changes into HCO₃ ^??>?Ca²⁺?>?Cl^??>?SO₄ ^2??>?Mg²⁺?>?Na⁺?>?K⁺?>CO₃ ^2?. In general, four water facies are determined and it is shown that alkali elements and strong acids are dominating over alkaline earth and weak acids. Statistical analysis including Mann?CWhitney U test indicate that physicochemical parameters in three of the five investigated basins [Gavkhuni, Ardestan and Central Iran desert (CID)] are similar, while Karoon and salt lake basins display different characteristics. The result indicate that groundwater west of the province is suitable for irrigation, while in the central and eastern parts of the province the groundwater loses its quality for this purpose. It is concluded that mineral dissolution and evapotranspiration are the main processes that determine major ion compositions.     

A GIS approach for the assessment of groundwater quality in Wadi Rabigh aquifer,Saudi Arabia

A classification approach has been implemented in the present work by integrating traditional water sample analysis methods and Geographic Information System (GIS) capabilities in order to classify zones with acceptable groundwater quality for drinking. GIS extrapolation capabilities with their multi-conditional layering facilities were integrated together in order to assess in the determination of areas suitable for drinking purposes. This technique was implemented in Wadi Rabigh, Western Saudi Arabia, due to its significance as one of the most promising areas in the Western Province in the Kingdom of Saudi Arabia, owing to the establishment of King Abdullah Commercial City and King Abdullah University for Science and Technology (KAUST) nearby. Results show that only a limited area in the aquifer can be used for domestic purposes. This area is located in two separate patches in the upstream part of the aquifer while most of the aquifer water is categorized as brackish which might be used for agriculture purposes to a certain extent. The downstream area of the aquifer is very saline due to sea water intrusion effect.     

Delineation of groundwater salinization in a coastal aquifer, Bousheher, South of Iran

The geochemical processes controlling chemical composition of groundwater are studied using hydrochemical and isotopic data in Abdan-Dayer coastal plain, south of Iran. The salinity of groundwater in the coastal plain ranges from 1,000, a fresh end-member, to more than 50,000 μS cm^?1, a saline end-member. Groundwater salinity increases from the recharge area toward areas with a shallow water table close to the Persian Gulf coast due to direct evaporation and sea water intrusion as confirmed by mixing binary diagrams, stable isotope content, and Br^?/Cl^? ratio. Groundwater flow pattern in the study area has been modified due to over-pumping of groundwater in recent years which resulted in further saline water migration toward fresh water and their mixing. The maximum mixing ratio is estimated about 15% in different parts of the study area according to chloride concentration.     

Geochemical and quality assessment of groundwater of Marand Basin, East Azarbaijan Province, northwestern Iran

The chemical analysis of 83 water wells in the Marand area, Azarbaijan Province NW of Iran was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. Over the entire area, the dominated hydrochemical types are Ca? +?Mg?+?SO₄?+?Cl, Ca?+?SO₄, Na?+?Cl and Ca?+?Mg?+?HCO₃. Based on the total hardness, the softness of the groundwater is determined. According to electrical conductivity (EC) and sodium adsorption ratio (SAR), the most dominant classes are C3?CS1, C3?CS2, C4?CS2 and C2?CS1. The major ion concentrations are below the acceptable level for drinking water. The groundwater salinity hazard is medium to high, but the Na hazard is low to medium; with regard to irrigation water, the quality is low to medium. So, a drainage system is necessary to avoid the increase of toxic salt concentrations.     

Using hydrochemistry and environmental isotopes in the assessment of groundwater quality in the Euphrates alluvial aquifer,Syria

Hydrochemical and environmental isotope methods were used to characterize the groundwater quality in ten wells belonging to the Euphrates alluvial aquifer in Syria, with the aim to assess the origin and dynamic of groundwater salinization in this system. The Euphrates River (ER) water along its entire course in Syria is rather fresh (TDS < 0.5 g/L), and thus, it is suitable for drinking and irrigation purposes. Groundwater salinity progressively increases from north to south, changing from almost freshwater (TDS < 0.6 g/L), with a Ca–Mg and HCO₃ type near the Syrian–Turkish border to brackish water (1 < TDS < 3 g/L), with a Ca–Mg or Na–Ca–Mg and SO₄–HCO₃ type in the vicinity of Al-Raqqa, and hence it can safely be used for irrigation. Downstream Deir-Ezzor the groundwater quality becomes fairly saline to very saline (3 < TDS < 29 g/L), with a Na–Cl type, and therefore it has an absolute hazard (SAR > 5) for irrigation uses. This pattern of chemical evolution, which is also clearly reflected in the variations of groundwater ionic ratios, completely agrees with the thermodynamic simulation results obtained by an experimental evaporation essay of a water sample taken from the ER near Deir-Ezzor. Stable isotopes permit the distinction between three main evaporation processes: under high, intermediate and low humidity conditions. Radioisotopes (³H and ¹⁴C) indicate the recent age and renewability of groundwater in this aquifer and confirm that its origin is entirely belonged to the ER water, either by direct bilateral interconnection or by vertical infiltration of the irrigation water totally taken from the ER. Relationships between major ions and δ¹⁸O values of the groundwater allow to differentiate between two main enrichment processes: either evaporation only or evaporation plus dissolution, that can explain altogether the development of groundwater salinity in such a dry area.     

Land subsidence due to groundwater withdrawal in Arak plain,Markazi province,Iran

With current trends of groundwater exploitation, the plains of Iran have been facing numerous problems, where subsidence is considered as the foremost obstacle. In the present study, the principle aim was to analyze the level of groundwater and induced subsidence effects in different regions of Arak plain from 2002 to 2008. Arak plain located in Meyghan Lake basin is subjected to subsidence process as a result of the declining groundwater levels. Monthly variations of groundwater levels were plotted using ArcGIS software. The results indicated declining water levels especially in Meyghan Lake than the Arak plains, resulting up to 36 m of drop in the groundwater levels of marginal areas in the plains during these years.     

Characterization of hydrogeologic properties of the Tabriz plain multilayer aquifer system,NW Iran

A detailed hydrogeological investigation was carried out in the Tabriz plain in Iran using conventional hydrogeological field investigations and hydrochemistry. The study was carried out because the aquifers are of particular importance as they are more or less the only source of water supply available to the rural population and for agricultural and industrial activities. Analytical and numerical methods were applied to the constant rate pumping test data from the Tabriz airport and the Tabriz Power Station well fields. Two types of aquifers of different water quality were identified in the study area: an unconfined aquifer that extends over the plain and confined aquifers that are found in the deeper layers of the multilayered sediment terraces of the Aji-Chay River course. Therefore, the central part of the Tabriz plain contains both unconfined and confined aquifers, while close to the highlands, there is only an unconfined aquifer. There was evidence of minor leakage in the confined aquifers when the numerical method was used for analysis. The groundwater in the area can be identified by three main geochemical facies: Na-Cl, Ca-HCO₃, and mixed Ca-Mg-Cl-SO₄. The processes responsible for the hydrochemical evolution in the area fall into five categories: dissolution of evaporate minerals, precipitation of carbonate minerals, evaporation, ion exchange, and anthropogenic activity.     

Hydrogeochemical characterization and groundwater quality assessment in the intensive agricultural zone of the Upper Cheliff plain,Algeria

The alluvial aquifer of Upper Cheliff (northern Algeria) is known for its intensive agricultural activities, which is based especially on groundwater exploitation. This aquifer is now facing a dual problem of quantity and quality, with a decrease in the groundwater levels and an increase in mineralization. Twenty monitoring samples were collected and analyzed for major ion during the dry season 2014. In the present study, we try to characterize the hydrogeochemical processes and to assess the impact of natural and anthropogenic conditions on groundwater mineralization. The analytical results of the dry season 2014 show a groundwater quality slightly alkaline (pH > 7) and indicate that the majority of samples have a values exceeding the limits of potability fixed by WHO in 2008, due to the various sources of anthropogenic pollution. The Piper diagram shows the dominance of groundwater types: Ca–Cl, the mixed facies (Cl–SO₄–Ca–Mg), and Ca–HCO₃: The mineralization process in this aquifer is mainly controlled by the lithology of the aquifer (exchange water–rock and weathering of calcareous crust dissolution in the unsaturated zone), by anthropogenic factors (discharges of untreated urban sewage, intensive use of fertilizers in agriculture and the use of domestic septic tanks by rural inhabitants) and also by geoclimatic conditions (semiarid climate). Suitability of groundwater shows more than 80% of samples have very poor quality for drinking and more than 20% of samples indicate a quality unsuitable for irrigation.     

Hydro-geochemical evaluation of groundwater with studies on water quality index and suitability for drinking in Sagardari,Jashore

Sagardari union is facing groundwater crisis because of contaminations from agriculture and urban sewage, which bring a considerable change in water quality. In view of this, hydro-chemical analyses were undertaken on 35 groundwater samples and the following hydro-geochemical parameters, pH, total dissolved solids (TDS), total hardness (TH), electrical conductivity (EC), cations and anions, were analyzed. From the analytical results, it is found that pH value was lower than WHO drinking water standard and the middle-downstream portions of the investigation region show higher EC. The piper plot indicates that the groundwater in Sagardari falls in the categories of NaClHCO₃ hydro-chemical facies. Higher TH in groundwater was detected, but still in an acceptable range. In addition, salinity and arsenic ratio are higher and moderately higher, respectively. The spatial distribution of Groundwater Quality Index (GWQI) was determined by geo-statistical modelling of Sagardari union. The study provides information and supports the administration which to make better groundwater utilization and quality control in the Sagardari union.     

矿井水害防治中的水文地球化学探查方法

矿井水害防治中的水文地球化学(水化学)探查方法可分为利用地下水天然成分的探查和人工示踪探查两类。前者主要适用于中小比例尺规模(区域或矿区)的调查和研究；后者则主要用于对大比例尺规模(矿区或井田)的一些疑难和关键问题的深入认识和确定。水化学方法几乎可用于水害防治的各个阶段，尤其在矿井突水水源、通道、不同含水层水力联系及注浆效果等的探查和判别中成效显著。近年来水化学方法的发展趋向主要表现为更快速、更简便、更准确。