جستجوی مقالات مرتبط با کلیدواژه "hydrogeochemistry" در نشریات گروه "آب و خاک"

Corrosion and precipitation are two problems of water quality management for the water transmission and distribution systems. Hence, the present research was conducted to investigate the potential of corrosiveness and precipitation in the drinking water supply wells of Gorgan city using some indicators.

Here, the results of chemical analysis of 63 wells supplying drinking water in spring and autumn were used. First the temporal and spatial changes of physicochemical parameters were investigated using one-way variance statistical test and IDW method, respectively. The dominant type, the origin of chemical ions, and their evolution process in Gorgan aquifer were studied. In this research, water hardness, LSI, RSI, CR and LS were used to determine the corrosion and precipitation potential of drinking water in Gorgan city. Finally, the temporal and spatial changes of indices calculated in two seasons were investigated.

The high concentration of calcium ions in groundwater, due to the recharge of the aquifer by the limestone series located in the southern highlands, has increased its hardness. The results of RSI and LSI revealed that the majority of wells are corrosive and their water has the potential to decompose CaCO3. Also, the corrosive property of water in the direction of groundwater movement is significantly reduced and the water precipitation property is increased. Also, 90 and 98% of the groundwater resources of Gorgan city have a corrosion ratio of less than one. Therefore, it is possible to transfer water from most wells with any type of metal pipes.

This research has studied the hydrochemistry and quality of groundwater resources in Saravan area. According to the hydrograph of the water table, ground water level (from 2014 to 2019) has decreased (-7.88 m). The delay time between rainfall and water table is about one or two months, which indicates relatively good permeability in the alluvial aquifer. According to the EC map, the quality of groundwater has decreased from west to east, and the groundwater of qanat’s has better quality than the exploitation wells. Because the well's mother of the qanats is dug in the upstream part of the aquifer and inside the alluvial fan, which has better quality ground water, Also the drainage system of the qanats is in such a way that only the over flow of ground water comes out. In the groundwater of the studied areas, there are three types of water: NaCl, NaSO4 and NaCl (HCO3). In general, there is an increase in chloride and sodium from qanat water resources to wells in the studied area. Also, increasing the depth of the well has increased the percentage of chloride and sodium. According to the distribution map of discharge of wells, groundwater extraction in the west area is more than the east region. Based on the factor analysis, two main factors affecting the quality of the aquifers have been identified, the first factor is the dissolution of minerals, which controls the quality of water sources and the second factor is the factors controlling the acidity/alkalinity.

The studied region is located at 8 kilometer of west Mojen in the south of Mojen waterfall, a part of the Shahrood county. In order to study the hydrogeological and hydrogeochemical characteristics of springs in the area, discharge, electrical conductivity and temperature were measured from October 2017 to November 2018. Also, the concentrations of the main ions including Ca2+, Mg2+, Na+, K+, HCO3-, SO42- and Cl- have been measured in the water and environment laboratory of Shahroud University of Technology. The obtained results showed that the coefficients of variations for the physical and chemical characteristics for all springs are negligible and confirm the dominant diffuse flow system in the study area. Recession curve of the studied springs has solely one coefficient of discharge (α) with a gradient of 0.009 which indicates the dominant diffuse flow system in that karstic aquifer. One of the main reasons for the emergence of the springs in the studied region is contact of groundwater in the karstic catchment of these springs (Limestone rock formations of the Cretaceous and Lar) with impervious units (marls and marly limestone). According to the springs of the area are overflow springs and all these springs are drained from an aquifer. Hydrochemical diagrams related to samples prepared from the studied springs in June 2017 show that all samples are high in Ca2+ and HCO3-, and are located in a specific range of karst waters. The ratio of Ca2+ ion to Mg2+ ion concentration is used to determine the predominant aquifer in karst areas. The average ratio of Ca2+ ion to Mg2+ ion for the studied samples is about 2.60, which can be concluded that the predominant lithology of the studied karstic aquifer is limestone. Also in this research, the primary catchment area of the springs was drawed. Then precision of this primary catchment area was evaluated by the water budget method and comparing its values of annual discharge and recharge volumes. According to the mentioned comparison a relative error of 0.8 percent was obtained. Due to the negligible relative error between annually recharge and discharge volumes and as well as the stratigraphic status in the regionin the region, the drawn catchment area is quite accurate.

Water resources quality assessment of the dam sites is one of the primary studies in the designing of these structures. The main challenges in Iran are the reduction of water resources and the limitation of groundwater exploitation. Much of these resources are formed in karst water resources in the karstic susceptible formations such as the Asmari carbonate formation in Zagros Mountain, Iran. In this study using laboratory and field studies, various parameters and indices were assessed to investigate the water resources quality of Bazoft dam site for different purposes. Bazoft dam is a double-curvature arch dam with a height of 211 meters which is located in Chaharmahal and Bakhtiari Province of Iran. The bedrock of the dam site consists of limestone and dolomite rocks of the Asmari and the Jahrom formations. The Jahrum formation formed the right abutment, the riverbed and the lower parts of the left abutment. The Asmari formation formed the rocks in the middle and upper part of the left abutment. After field studies, chemical analyses have been performed on the collected water samples from the water resources such as springs, river and the exploratory boreholes in the dam site. PH and electrical conductivity (EC) were measured by pH meter and electrical conductivity apparatus was measured at 25 ° C. Concentration of ions such as calcium, magnesium, bicarbonate was measured by titration method. The concentration of ions such as sodium and potassium, sulfate and nitrate were measured  using the Flame-Photometry, and Spectrophotometry methods, respectively.. The test error in all cases was low and the results were confirmed. The indices such as Langelier saturation index and Ryznar stability index, sodium adsorption ratio (SAR), soluble sodium percentage, residual sodium carbonate, permeability index, Kelly ratio, were calculated based on related equations. Principal factor analysis (PCA) is used to determine the most influential variables when the number of variables is investigated and the relationship between them is unknown. In this method the variables are set on the elements so that the first factor is reduced to the next factor of the variance, hence the variables that are based on the first factors are the most influential. PCA reduces the dimensions of the initial data by turning the main components around the vertical and horizontal axes of coordinates. This rotation actually increases the variance between the main components and therefore it is called Variance Maximize Varimax or orthogonal rotation. The Varimax command is one of the most common methods of orthogonal rotation that preserves the independence between the extracted agents. This method reduces the number of the larger factor loadings to the lowest number. In this method, the scree plot chart determined the number of factors extracted. Parameters of R2 and RMSE in order to investigate the performance of relations have been used. As R2 is closer to the one and the RMSE is closer to the zero, the proposed relationship will yield better performance. Anions such as HCO3, Cl, SO4, CO3 and NO3 and cations such as Ca, Na, Mg, and K are the most, respectively. From the viewpoint of hardness, all waters are placed in the hard category. According to the percentage of Na, the spring’s water is excellent, the water of the borehole is good and the river is acceptable. The results of factor analysis showed that 87.13 percent of the water quality variations are controlled by four factors. The most important factors affecting the water quality of the dam site include EC, TDS, Na %, SAR, Cl, SO4, alkalinity, Na, and CO3 with 50.91 %. The second factor include calcium, magnesium, potassium ions with 15.82 %, the third factor include nitrate, bicarbonate, and hardness with 11.61 % and pH and carbonate with 7.17 % are fall into the fourth factor. The correlation matrix of the parameters was investigated and the accuracy of some relationships was examined on the basis of different statistical criteria. The relationships of LSI with RSI and EC with TDS in the dam site and their comparison with previously suggested equations indicated that there is a high correlation and each relationship is applicable for a particular area. Also, the trend of points obtained from each equation has the appropriate consistency but the RMSE of the assessed equations is high. EC plot against TDS to determine the relationship between the two parameters in the Bazoft dam site is TDS=0.70Ec-31.24. The concentration of all assessed cations and anions is lower than the WHO permissible limit. The water resources are corrosive and all indices indicated the appropriate quality of water resources for farming and drinking.

This study investigated the hydrogeology and hydrogeochemical processes of groundwater in the Harzandat plain aquifer. The Harzandat basin shown in Figure 1 is located northwest of Tabriz, the city in the northwest region of Iran. It is a subbasin of the Khazar basin. The Harzandat basin is about 347 km2. This includes 146.7 km2 of the Harzandat plain and 200.3 km2 of Mountainous areas. The highest elevation of the Harzandat basin is 2623 m above mean sea level (amsl) at the old Harzandat and the lowest elevation is 1,274 m amsl at Zal railway station. Based on de Martonne (1925) and Emberger (1930), the prevailing climate in the Harzandat plain is arid-cold. Average annual precipitation is about 219 mm (Chercher climatological station, 2012-2013).
In the last decades, this aquifer suffered from severe groundwater level declination and caused degradation of groundwater quality. To better understand of hydrogeochemical processes in Harzandat plain, groundwater samples obtained 77 from 16 different water wells, springs and qanats between 2002 and 2013 and used them to characterize the hydrogeochemistry of the Harzandat plain aquifer. The location of the sample sites is shown in Figure 3. The samples were analyzed in the hydrogeological laboratory of University of Tabriz and in the laboratory of East Azerbaijan Regional Water Authority. The water quality parameters of interest were , , , , , , , and , which were determined by the standard methods (American Public Health Association 1998). Moreover, pH, electric conductivity (EC), the total dissolved solid (TDS) were measured from the samples. Total hardness (TH), sodium absorption ration (SAR), and sodium percent (Na%) were calculated from the measured chemical parameters. Samples collected from groundwater resources were analyzed through the graphical and multivariate statistical methods.
Graphical methods (e.g., a Piper diagram, a Durov diagram, a Stiff diagram, etc.) are commonly used to interpret hydrogeochemical processes (Stiff 1951; Piper 1944; Hem 1986; Durov 1948; Lloyd 1965). Piper diagrams were used to deduce groundwater types and an expanded Durov diagram improves the Piper diagram by providing a better display of different types of water as well as important hydrochemical processes, such as ion exchange, simple dissolution and mixing of waters with different qualities. A Stiff diagram compares analytical data in pairs and infers types of source rocks (Stiff 1951; Hounslow 1995). Although the graphical methods are commonly used to interpret hydrogeochemical processes, they have several limitations as they cannot analyze neutral chemical species (e.g., SiO2 and ) and nonchemical data (e.g., temperature) (Voudouris et al. 1997).
Multivariate statistical methods (e.g., factor analysis (FA) and hierarchical clustering analysis (HCA)) are able to complement the limitations of the graphical methods for hydrogeochemical process interpretation (Cloutier et al. 2008). Multivariate statistical analysis is able to explain the correlation among a large number of variables and reduce the number of variables into a small number of factors without loss of essential information. In multivariate statistical methods, factor analysis was frequently used to investigate hydrogeochemical origins (Voudouris et al. 2000). Factor analysis was also applied to investigating groundwater contamination. Clustering analysis was used as a classification technique for hydrogeochemical type investigation and the interpretation of their origin (Cloutier et al. 2008).
The results of the Piper diagram shows two groundwater types and the Stiff diagram showed six different sources of groundwater samples. The Durov diagram identified two major hydrogeochemical processes in the aquifer. However, Hierarchical Cluster Analysis (HCA) identified five water types in the groundwater samples, because HCA was able to use more chemical and physical data than graphical methods. The HCA result was checked by discriminant analysis method and the classification accuracy of groundwater resources samples and confirmed by this method. Based on the factor analysis method, four main effective factors were found on the hydrochemistry of the Harzandat plain aquifer. First, second and third factors show the effect of geological formation and general groundwater trend on hydrochemistry of the area. The fourth factor seems to be related the influence of human activities. In the first factor, chloride, sulfate, magnesium, calcium and electrical conductivity, and in the second factor percentage of sodium and sodium absorption ratio, and in the third factor potassium and bicarbonate is effective, while, in the fourth factor carbonate were related to nitrate and acidity. In fact, the first, second and third factors are geogenic, and the fourth factor is anthropogenic.

Zahedan aquifer is located in the northernof Zahedanwatedshed. It is essential to evaluate the quality of groundwater resources due to proving some part of drinking water, agricultural and industrial waters of this city. In order to carry out ground water quality monitoring, and assess the controlling possesses and determine cations and anions sources of the groundwater, 26 wells were sampled and water quality parameters were measured.The results of the analysis showed that almost all of the samples proved very saline and electrical conductivity varied from 1,359 to 12,620μS cm−1. In the Zahedan aquifer, sodium, chloride and sulfate were predominant Cation and Anions respectively, and sodium-chloride Na-Cl(and sodium - sulfate)Na-So4) were dominant types of the groundwater. The factor analysis of samples results indicates that the two natural and human factors controlled about the 83/30% and 74/37% of the quality variations of the groundwater respectively in October and February. The first and major factor related to the natural processes of ion exchange and dissolution had a correlation with positive loadings of EC, Ca2+, Mg2+, Na+, Cl-, K+ and So42- and controls the 65.25% of the quality variations of the ground water in October and the 58.82% in February. The second factor related toCa2+, No3- constituted the18.05% of the quality variations in October and 15.56% in February, and given the urban development and less agricultural development in the aquifer, is dependent on human activities. For the samples collected in October, the saturation indices of calcite, gypsum and dolomite minerals showed saturated condition and calcite and dolomite in February showed saturated condition for more than 60% and 90% of samples and gypsum index revealed under-saturated condition for almost all samples.The unsaturated condition of Zahedan groundwater aquifer is resulted from the insufficient time for retaining water in the aquifer to dissolve the minerals. So42- and No3- Ions in more than 70 percent samples showed unnatural sources (the sewer infiltration).

In geo-statistics, prediction of an unknown value of random field has been performed in specified time and position, using spatio-temporal Kriging. In some circumstances, a suitable covariate increase the estimation prediction. Geo-statistical methods of Universal Kriging (UK) and Kriging with External Trend (KwET) were applied to Mashhad plain water quality data sets. The optimal network to monitor groundwater quality was presented, using Entropy. All wells ranked based on the criterion of Entropy and mutual information. Then, the optimal network was determined based on the percentages of acquired information and relying on the spatio-temporal Kriging. Based on UK and KwET, electrical conductivity (EC) was the best covariate. KwET with EC as a covariate was the superior Kriging method. A network covering 111 wells showed to be as informative as the existing monitoring network with a total of 237 wells.

Wastewater can be used effectively in irrigation to provide some portion of the water required for agriculture purposes. But for using of the wastewater, the accurate monitoring on their quality should be done. In order to know the quality and suitability of waste water of coal cleaning factory of Vatani for irrigation purpose, the sampling from wastewater ponds and groundwater have been done during winter 2009. According to the hydrochemistry facies of Piper diagram, the wastewater and groundwater types in the studied area belongs to Ca-SO4 type and Ca-HCO3 type respectively. Sodium absorption ratio (SAR) (class S1), sodium percent (%Na), magnesium hazards and chloride potential are less than 10%, 60%, 50% and 20% respectively. The residual sodium carbonate (RSC) (1.25 meq/l) and kelly's ratio (1) for all the studied samples. Indicate that they meet acceptable quality for agricultural purposes. Wastewater studies are based on U.S. Laboratory's Salinity diagram, is in the range C3S1 in respect to ground water (C2S1) and shows high salinity. Wastewater studied samples on the Wilcox’s diagram lies in the area of permissible waters for irrigation. The Gibb's model shows that anions and cations of all the type of waters are of lithological origin. The positive chloroalkaline index of waters indicates that base-exchange reaction occurred between Na+ and K+ of the groundwater with Ca2+and Mg2+ of coal and coal tailings. The permeability index (PI) of all samples are permissible for irrigation.