mojtaba g. mahmoodlu

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.

Background and Groundwater serves as the primary drinking water source in Golestan Province. Therefore, this study aims to assess the non-cancerous health risks associated with nitrate and fluoride in the province's drinking water sources.  Physicochemical data from 139 drinking water wells were obtained from the Golestan Province Water and Wastewater Company during the spring and autumn. Significant ion variations were analyzed, and factors influencing the chemistry of drinking water sources in Golestan Province were investigated. Non-carcinogenic health risks posed by nitrate and fluoride were assessed using two indicators provided by the United States Environmental Protection Agency.  The maximum nitrate concentration in certain Golestan Province cities exceeds the Iranian drinking water standards (1053) and the World Health Organization's limits. However, fluoride levels in most cities fall below the range stipulated by domestic and international standards. The nitrate risk factor for children in select cities exceeds one, while it remains below one for other age groups. Notably, Khan Bebin City exhibits the lowest nitrate risk factor among the province's cities. Additionally, risk factor values show a slight increase during the autumn season. Non-cancerous health risk assessments for fluoride in drinking water sources across Golestan Province during spring and autumn indicate risk values below one for all age groups, including infants, children, teenagers, and adults.  The health risk assessments for nitrates and fluorides indicate that children in certain cities face a higher risk from nitrates than adults. Moreover, the low fluoride levels in the province's drinking water sources increase the likelihood of tooth decay.

Currently, soil erosion is considered one of the important environmental problems in Iran's watersheds. Accurate estimation of sedimentation and soil erodibility is very important for the protection and management of natural resources. Soil erodibility indicates the potential ability of soil to erode, and its increase is considered a serious threat to the stability and production capacity of agricultural lands. Measuring soil erodibility by direct method is expensive and time-consuming, and nowadays indirect methods are used to determine it. One of the most common indirect methods for estimating this parameter is the use of the Wischmeier and Smith nomograph, which was developed for non-calcareous soils. However, the majority of the soils in Iran is calcareous and the use of the nomograph method does not provide a correct estimate of the amount of erodibility. Loess is one of the most important Quaternary sedimentary formations in northeastern Iran, which consists of a relatively high percentage of lime. Therefore, the main goal of current research is to determine the most suitable indirect model to determine soil erodibility in Loess lands with the origin of calcareous sediments.

In the current study, Arab-Qara-Haji watershed with an area of 2596 hectares located in the east of Golestan province was selected as a typical loess area. The average annual precipitation of this watershed is 489 mm and it has a moderate semi-arid climate. This area is one of the sedimentary basins of Kopeh-Dagh zone related to the Jurassic period and consists of limestone and loess sediments. Based on the field studies, three main types of soil including hills (67.1%), loess plateaus (20.6%) and river terraces (12.3%) were identified in this watershed and the land unit was selected as working units. For this purpose, 48 surface samples (0-10 cm depth) were collected from each part of the land unit. In this research, two series of samples were taken from each section. The first series of samples was used to determine the soil physicochemical properties and the second series was sampled by a special cylinder to determine the soil saturated hydraulic conductivity using the falling head method. In the laboratory, soil texture was determined by hydrometric method (D<0.075), soil granularity by sieve analysis (D>0.075), soil organic matter by wet burning method and neutral lime percentage by Nelson method. The experience of the soil expert of this research was used to determine the soil structure in field. Then, soil erodibility was estimated using four indirect methods, including Weishmeier and Smith nomograph, Torri, Shirazi, and Vaezi. In this study, the soil actual erodibility was measured using rain simulator in the field (in plots of 1 m2). Then the validation of the models was performed using three standard indices MAD, RMSE and MAPE and the most appropriate model was selected.

Soil texture assessment in this watershed revealed that around 90 percent of soil samples have silt loam texture and the rest of samples has loam one. Also, the average lime in study area was estimated about 29%. The high percentage of lime (29%) and silt (60%) in this watershed has greatly increased the tunnel erosion probability. The validation results of the used models revealed that the use of the Vaezi method to estimate the soil erodibility factor in the loess lands of the study area has the highest accuracy (RMSE=0.00225). However, it is less estimated than the actual values. These results were confirmed in all 3 soil types of Arab-Qara-Haji watershed. After Vaezi model, Shirazi model (RMSE=0.03600) is more suitable than other models to estimate the soil erodibility factor in the loess lands of the area. This model has overestimated in all three types of soil including hill, loess plateau, and alluvial terrace, which is 11.2 times higher than the actual data from the rain simulator in the Arab-Qara-Haji watershed. After the Vaezi and Shirazi models, Wischmeier nomograph and Torri models, respectively, have a weaker performance in determining the soil erodibility factor in the limestone lands of the study area. Like the Shirazi method, Wischmeier nomograph and Tori methods have overestimated the soil erodibility factor. In the study area, this increase has been18.6 and 21.9 times higher than the actual data for Wischmeier nomograph and Torri models, respectively.

The present research results revealed that the use of Vaezi model to estimate soil erodibility in loamy lands with a high percentage of neutral lime is more appropriate compared to other used models. Based on the Vaezi and colleagues model, if the amount of neutral lime in the soil is less than 13%, it has a controlling role on the soil erodibility factor. While, this model is not able to estimate the soil erodibility in areas with neutral lime more than 30%. Therefore, for a number of soil samples in which the neutral lime was above 30%, the Vaezi model was not able to calculate the soil erodibility factor. It seems that currently, for the areas where the percentage of neutral lime in the surface soil is less than 30%, the use of the Vaezi model is more suitable than other models. It is suggested to recalibrate and update the Vaezi model for areas where the percentage of lime is more than 30%. The present research results revealed that the use of Vaezi model to estimate soil erodibility in loamy lands with a high percentage of neutral lime is more appropriate compared to other used models. Based on the Vaezi and colleagues model, if the amount of neutral lime in the soil is less than 13%, it has a controlling role on the soil erodibility factor. While, this model is not able to estimate the soil erodibility in areas with neutral lime more than 30%. Therefore, for a number of soil samples in which the neutral lime was above 30%, the Vaezi model was not able to calculate the soil erodibility factor. It seems that currently, for the areas where the percentage of neutral lime in the surface soil is less than 30%, the use of the Vaezi model is more suitable than other models. It is suggested to recalibrate and update the Vaezi model for areas where the percentage of lime is more than 30%.

In Iran, the climatic conditions are such that even in the rainiest areas of the country, there is a need for groundwater resources, and this demand is increasing every year. Since, groundwater is one of the most valuable water resources in Iran, it is very necessary to predict its changes in order to use it optimally with the aim of sustainable development. One of the most complex hydrological processes in nature is the rainfall-groundwater level process, which is affected by various physical and hydrological parameters. Although, various models have been presented to predict the changes in the groundwater level using the rainfall patterns, but less attention has been paid to the transfer function model. Hence, the main objective of this research is to introduce and use the transfer function (TF) model to predict the monthly groundwater level using rainfall data and to compare its results with ANFIS and Artificial Neural Network (ANN) models.In the present study, 30-year data (1992-2021) of meteorological stations and observation wells in 3 watersheds of Galikesh, Ramian and Mohamadabad were used to model the rainfall and groundwater level. of the Gorganroud river basin.Then, considering that the years closer to the present time have more accurate information about the situation of this time, the years were considered as a forward process in artificial neural networks. The model fitting and prediction of the groundwater level values using rainfall data for the next 12 months was performed with applying three models: Artificial Neural Network (ANN), Adaptive neuro fuzzy inference system (ANFIS), and transfer function (TF). For this purpose, MINITAB SAS, SPSS, and R software were used. Next step, the validation of the values predicted by the models was evaluated using three indices Mean Absolute Distance (MAD), Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE).The results of the autocorrelation plots of the groundwater level of the wells revealed that all time series have a seasonal trend with a period of 12 months. Based on the cross-correlation plots, it was also found that rainfall has direct effect on the groundwater level in the two watersheds of Galikesh and Mohamadabad with lag time of three months and in the Ramian watershed with a delay of one month. The validation results of the models using three indexes MAD, RMSE and MAPE revealed that the artificial neural network model for predicting the groundwater level using monthly rainfall data in all three investigated watersheds had the most appropriate performance (RMSE=0.0778, 0.0243, 0.0532m) and the ANFIS model is ranked second (RMSE=0.1841, 0.0832, 0.1012m). Although the transfer function model was less accurate than the other two methods (RMSE=0.5711, 0.5023, 0.3234m), but this model has performed well in fitting the monthly groundwater level values. This model is very effective in identifying the delay in the impact between the input and output variables, as well as expressing the model based on which the impact of rainfall can be expressed as a model.The results of this research show that all three models of artificial neural network, ANFIS and transfer function can be used to predict the groundwater level using monthly rainfall values. Consecutive overestimation and underestimation, which increases the error and decreases the performance of the models, was not observed for the three used models. Also, all three models perform well in detecting trends and data changes. However, the artificial neural network model is more accurate than the other models. In addition, when forward process is used in artificial neural network modeling, compared to the case where the complete series of data is used, the efficiency of the model is significantly improved.

Fluoride is one of the important ions in drinking water, which in low or high concentrations causes some problems related to human health, such as tooth decay, dental fluorosis, or skeletal fluorosis. Present study was carried out to investigate the fluoride concentration as well as the effective factors in the fluoride distribution in drinking water supply sources of Golestan province.

For this purpose, Golestan province was divided into four regions according to the distribution of loess. Next, groundwater samples from these areas were collected and chemical parameters of TDS, HCO3-, Cl-, SO42-, NO3-, NO2-, F-, PO42-, Ca2+, Mg2+, Na+, K+ and Fe2+analyzed. After hydrogeochemical and statistical assessment, the relationship between fluoride and loess deposits and some physicochemical parameters were investigated.

Results of four regions showed that the fluoride amount is directly related to the loess deposits spread, so that in region 1 including Maraveh Tappeh, Kalaleh, and Gonbad there is the most spread of loess deposits, the fluoride amount is more than other areas. Results revealed that high correlation of fluoride with some ions such as calcium, bicarbonate, iron, sodium, and phosphate. Also, there is a high correlation between electrical conductivity as a salinity parameter and fluoride concentration in groundwater. So, an increase in salinity, the fluoride amount in the province's water resources has increased significantly. Water-rock reaction is the main factor controlling the groundwater chemistry and as a result, most possible factor for the fluoride leaching into groundwater.

Chemical cement of loess along with some clay minerals is the main source of fluoride in groundwater sources in region 1 with the most spread of loess deposits. Saline water of the lower layers and their intrusion into the fresh water aquifer can be considered as the fluoride second source in Gorgan Plain.

It is important to find a simple connection between physic-chemical parameters and indices due to complexity and difficulties of using some indices. This research was performed to determine the relationship between physicochemical parameters and water quality indices

In this research, dominant water type of Gamasyab and GharehSou rivers was first determined using radial diagram. Then, to classify the water quality of two rivers, 14 quality water indices together with national standards for drinking water 1053 and WHO were used. Linear regression was used to determine the relationships between quality indices and physicochemical parameters. Finally, for the accuracy of the results of linear regression, the obtained relationships were tested for two other water sources (river and Gorgan Bay).

Based on hydrochemical results, the predominant type of water in both rivers is Ca-HCO3. Based on diagrams and criteria related to drinking and agriculture, the water quality of both rivers is in the desired range. The results of Langelier, Ryznar, Larsson-Skold and Puckorius indices showed that water quality for the industrial sector was relatively corrosive. Also, the water quality at the study stations is suitable for livestock drinking. The results of linear regression between quality indices with physicochemical parameters of water and some ion ratios showed that the resulting relationships for calculating quality indices can be used for different water types from fresh to saline. Also, comparing the results of linear regression simulations with water quality indicators, indicates the high accuracy of the relationships in water classification for different uses.

Groundwater is one of the most valuable water resource in Iran, which is mainly influenced by rainfall patterns in a region. In the present study, 30-years rainfall and groundwater level data were used in the three watersheds of Galikesh, Ramian and Mohammadabad to model the rainfall and groundwater level. The prediction of the groundwater level using the rainfall data for the next 12 months was done using the Transfer Function (TF) and using SAS and MINITAB software. Validation of predicted values was done using MAD, RMSE and MAPE indices. The results showed that according to the autocorrelation diagrams, all time series have seasonal trend with a period of 12 months. The results of the autocorrelation diagrams showed that in Galikesh and Mohammadabad watersheds, rainfall has a direct effect on the groundwater level with a delay of three months, but in the Ramian watershed, this delay was one month. It was also found that the transfer function model had a good performance in fitting the monthly groundwater level in all 3 studied watersheds.

Doogh river is one of the main tributaries of Gorganroud in the east of Golestan province, which has an important role in supplying drinking water to Gonbad Kavous. Furthermore, it is one of the water supply sources of Golestan dam with agriculture use. Therefore, the study of hydrochemical and water quality of this river for drinking, agricultural, and industrial uses is of great importance. In this study, Stiff, Piper and Gibbs diagrams were used to investigate river hydrochemistry. Wilcox, sodium soluble percentage, magnesium ratio, and permeability index was evaluated to classify water for irrigation purpose. To investigate Doogh river water for drinking purpose, NSFWQI index, Schoeller diagram, and water quality standards were used. Eventually, water quality for industry was assessed using corrosivity ratio, Langelier Ryznar indices. Results showed Ca-Mg-HCO3 is dominant hydrochemical facies and rock-water interaction is the main controlling factor in river water chemistry. Based on NSFWQI index and Schoeller diagram, water quality was in acceptable class for drinking purpose. However, turbidity and fecal coliforms values based on water quality standards were higher than drinking limit and needs to be purified. Based on the results of sodium percentage, magnesium ratio, and permeability index, water quality is well evaluated for agriculture purpose. Industrial indices indicate that the relatively corrosive property. Water quality for irrigation purpose is well evaluated and there is no need for soil regeneration after use. Although Doogh river water is relatively corrosive, but it is save to use all metallic equipment to transfer and extract water

Corrosion and precipitationare physicochemical processes that reduce the amount of water flow in water transfer pipes and the effective life of water supply facilities, increase the energy consumption for water transfer, and cause some diseases among consumers. The present study was conducted to investigate the corrosion tendency and precipitationalong the Gorganroud River from highlands to the Gorgan Gulf.

In this study, the results of the analysis of 11 physicochemical parameters (Calcium, Magnesium, Sodium, Potassium, Bicarbonate, Sulfate, Chloride, total dissolved solids, electrical conductivity, temperature, and pH) of the Gorganroud River during a period of 10 years were used (2004-2014).First, the annual mean changes in the qualitative parameters of water samples during the statistical period of the studied stations were investigated. Then, triangular diagrams were used to assess the Gorganroud River hydrochemical at the studied stations. Next, changes in water hardness as an important qualitative parameter in the industrial, agricultural, and drinking sectors were investigated along the Gorganroud River. Saturation indices were used to predict and the probability of precipitation or dissolution of some carbonate minerals (such as calcite, dolomite) and evaporites (such as anhydrite, gypsum, and halite) along the Gorganrood River. Then, the trend of changes in Langelier, Ryznar, Puckorius, Larson-Skold corrosion indices, corrosion ratio, and the calcium carbonate precipitation potential of Gorganroud River at four stations was investigated. Next, a one-way ANOVA test was used to investigate the significance level of indices in the studied stations. Finally, the relationship between mineral saturation indices and corrosion indices was investigated.  

Based on the accumulation and distribution pattern of the samples in the triangular diagram, the dominant water type in the Gorganroud River is bicarbonate on the margin of heights, and as it enters the plain and the chloride ion concentration increases, it tends to reach full maturity, the sodium chloride type. Hardness increased along the water movement path. The results of saturation indices showed that the river’s water is supersaturated with carbonate minerals and undersaturated with evaporite minerals. Based on Ryznar, Puckorius and Larson-Skold indices, Gorganroud River water tends to cause corrosion. However, the precipitation rate increased from the margin of highlands to Gorgan Gulf. The results of the calcium carbonate precipitation potential and Langelier Index indicated that Gorganroud River tends to precipitation over the study area. Investigation of the relationship between saturation indices with corrosion indices and calcium carbonate precipitation potential showed linear relationships between qualitative indices and saturation indices. The results of the statistical test showed a significant difference between the calculated indices in the studied stations.  

Although based on the hydrochemical results the main factor controlling water chemistry of the Gorganroud River was the water-rock reaction, factors such as saline water intrusion of Gorgan Gulf in the lower part of the river and inflow of untreated effluents into the river caused rapid hydrochemical evolution of the river and reached the sodium chloride type. Increasing the number of physicochemical parameters along the river path in addition to increasing the water hardness, has reduced corrosion and increased precipitation rate. Statistical results showed a clear linear relationship between saturation indices and corrosion and sequestration indices in water.

In order to investigate the effect of flood in March 2019 on quantitative and qualitative changes of groundwater, the floodplain at the end of Gorganroud river basin, which was naturally exposed to floods, was selected. To investigate changes in groundwater quantity and quality, 17 and 11 observation wells with suitable distribution in the study area were selected, respectively. Then, quantitative (groundwater level) and qualitative data (11 physicochemical parameters) of wells were collected in two periods before and after the floods. First, groundwater level changes in two periods were evaluated by paired T-test and average groundwater level of the plain. Then, physicochemical characteristics changes in two periods were evaluated using paired T-test. Finally, hydrogeochemical changes were assessed using Gibbs, Durov and Piper diagrams, and the water quality for agricultural and drinking purposes were investigated using Wilcox and Schoeller diagrams. Paired T-test results showed that the groundwater level in 88.2% of the observation wells after the flood had a significant increase. This has increased the groundwater level as well as the unit hydrograph of the plain (about 2 meters) after the flood. The results of changes in groundwater quality parameters showed that the amount of EC, anions and cations (except NO3) were decreased in most of the observed wells after the flood. This has reduced the hardness of groundwater but has not had a significant effect on the type and hydrogeochemical facies of floodplain groundwater. The reason can be the hydrochemical similarity of infiltrated water and groundwater of the plain aquifer.

The use of packaged drinking water is on the rise nowadays in most countries, including Iran. Currently, more than 100 different brands of packaged drinking water are produced and distributed in Iran. This study was done to evaluate the quality of Iranian, foreign packaged drinking waters and municipal drinking water in Golestan Province, north of Iran.

This descriptive-analytical study was done on 56 packaged drinking waters of different Iranian and foreign brands, eight brands produced in Golestan province and a number of municipal drinking water samples were collected from Gorgan and Gonbad Kavous cities in northern Iran. To assess the quality of packaged drinking water and drinking water, their physicochemical parameters were compared with National Iranian Standards 1053 and WHO. Stiff and Piper diagrams were plotted to determine the type and hydrochemical facies of water samples. Gibbs and Schoeller diagrams were used to determine the water chemistry controlling factors of water samples and their water quality for drinking, respectively.

The concentrations of physicochemical parameters (except bicarbonate) were within the range of national drinking water standards 1053 and WHO. The average nitrate concentration in all packaged drinking and drinking water was within the standard range. The fluoride concentration of all packaged drinking waters and drinking water was within the range of WHO standard. However, only 14 samples of all packaged drinking and drinking water samples are within the range of 1053 National Iranian Water Standard. The total concentration of soluble solids and the total hardness of packaged drinking water were within the range of 1053 NW. There was also a significant difference (P<0.05) between the chemical parameters of magnesium, sodium, chloride and nitrate in packaged drinking water produced in Golestan province with the municipal drinking water samples.

The amount of fluoride in drinking water in this study was less than desirable and required fluorination. The quality of packaged drinking water in Golestan province is better than the municipal drinking water.

In this research, the biochar ability of Conocarpus and Paulownia plant as adsorbents to remove Nitrate, Ammonium, and phosphate from the water were investigated. For this purpose, the effect of contact time, initial concentration, and pH of solution on the removal of Nitrate, Ammonium, and phosphate by the biochar of Conocarpus and Paulownia plants have studied. The Conocarpus and Paulownia plants have been modified by ferrous chloride for nitrate removal. Conocarpus and Paulownia have been modified by potassium hydroxide for ammonia removal. Also, Conocarpus have been modified by ferrous chloride and Paulownia has modified by Potassium hydroxide for phosphate removal. The studied adsorbent properties with FT-IR and SEM, which their physical properties are: density, organic material percent, ash percent, mass moisture, and special surfaces have been determined by the methylene blue method. The Pseudo-First-order order, Pseudo-Second-order, Elovich, Intraparticle diffusion, and power have been used for describing the kinetic data. In addition, the Langmuir model, Freundlich, Temkin, Halsy, and Langmuir-Freundlich have used for describing the isotherm adsorption data. The results of this study showed that the Nitrate, Ammonium, and phosphate adsorption level has increased bypassing the time and after 60 and 120 min, they have reached their maximum level respectively. The maximum Ammonium adsorption level in modified biochar of Conocarpus was in pH=6, and in Palonia biochar was in pH=2 and the maximum nitrate adsorption was in pH=2. In addition, the maximum phosphate adsorption was in pH=8. By increasing the initial concentration of phosphate and nitrate, the removal efficiency has increased. The maximum phosphate removal efficiency in the concentration of 14mg/L in modified paulownia and Conocarpus biochar was 100%. In addition, the concentration of 50mg/L nitrate in modified Paulownia biochar was 98.37%. The maximum Ammonium removal efficiency in the concentration of 5 mg/ L by modified Conocarpus biochar was 82%.

Rivers water quality study can be a great help to water-resource management and planning. This study was conducted to investigate the water quality of Chehelchay River using the IRWQISC.

In this study, water samples were collected from seven different stations along Chehelchay River during a period of 6 months. In order to use IRWQISC, the physicochemical and biological some parameters were measured. After calculating the IRWQISC values for each station, the changes in the IRWQISC values were investigated along river. Then, the results of IRWQISC were compared drinking water and agriculture water standards.

The results of this study showed that Chehelchay River water was situated in a relatively good quality category based on the IRWQISC. IRWQISC diminished in the flow direction from the upstream sampling point to the outlet of basin resulting in a reduction in water quality of river. Results also showed that there is a direct relationship between IRWQISC and the rate of discharge so that the value of IRWQISC increases with increasing the rate of discharge.

The results of this study showed that the average IRWQISC index was better than summer season in spring. Flow changes and IRWQISC index indicate a direct relationship between them, with a slight increase in the rate of fluctuation. Comparison of parameters used in IRWQISC with drinking water and agriculture water standards showed the Chehelchay River water is suitable only for agriculture uses and it cannot be used for drinking purposes. Results showed that water purification must be performed to remove fecal coliform and reduce turbidity of water before using as a drinking water source.

In this study, to investigate the water quality of Gamasyab and Ghareh-Sou rivers in Kermanshah province, data from a 5-year statistical period during 2014-2018 was used. To evaluate the water hydrochemical properties, the water type and hydrogeochemical facies of rivers water were first determined using Stiff and Piper diagrams. Next, the controlling factors of the water chemistry of two rivers were determined using Gibbs diagram and Ionic ratios. Also, factor analysis and cluster analysis were used to determine the processes affecting the hydrochemistry of river water. Finally, to predict the possibility of dissolution and precipitation of some minerals, their saturation indices were estimated. The results showed that water type and facies are bicarbonate calcite in both rivers. Also, the main factor in changing the chemical quality of water in both Gamasyab and Ghareh-Sou rivers is water-rock reaction. According to the results of factor and cluster analysis, this factor can be attributed to the dissolution of (1) carbonate and evaporation (2) dolomite formations in the rivers watershed. However, the dissolution of carbonate formations due to their abundances and distributions two watersheds has a more significant effect on the change in water chemistry.This resulted an increase in some chemical parameters such as calcium, magnesium and bicarbonate in the water of these two rivers and also caused positive water saturation index for aragonite, calcite and dolomite minerals. Considering the low contribution of the second factor in changing the chemical parameters, the saturation indices for evaporative minerals of gypsum, halite and anhydrite is negative.

Springs are highly important habitats for biodiversity trend. Hence three springs in Golestan Province were selected for floristic study of diatom assemblages. Samples were collected seasonally from stony and sediment substrates. In total, 75 taxa belong to 38 genera were identified. Gomphonema and Nitzschia each with 7 species, Navicula with 6 sp. Surirella with 5 sp., and Cymbella with 4 sp. were the most species-rich genera. Results revealed that Gol-e-Ramian Spring with 61 taxa had the highest species richness. Achnanthidium nanum, Cocconeis placentula, Fragilaria crotonensis, Gomphonema micropus, Meridion circulare, Nitzschia vermicularis, and Planothidium frequentissimum were most abundant taxa. Most of the species identified in the present research have been observed within running water environments in Golestan province and other parts of Iran. Our study improved the knowledge of diatom communities in Golestan province springs.