groundwater

The study aimed at investigating the groundwater quality for drinking, agricultural and industrial uses by Wilcox and Schuller diagrams using Chemistry Software, Langelier Saturation Index (Is) and evaluating hazards caused by physical-chemical compounds using the health hazard parameters such as chronic daily intake (CDI) and hazard quotient (HQ) in EPA formulas in some parts of the Shiraz Plain, Central Fars Province. First, the data of 10 quality parameters affecting above-mentioned uses, including EC, Ca2+, K+, PH, SO42-, Cl-, Na+, TH, Mg2+ and TDS were collected corresponding to the study area’s 22 wells and their normal distribution was ensured. Regarding Wilcox and Schuller quality indices, the groundwater is classified as average for agricultural uses and as acceptable for drinking use. According to the Langelier Saturation Index, the existing water resources were reported corrosive to scale forming. During the sampling period, the average HQ index values for Ca2+, Mg2+, K+, Na+, Cl-, HCO32-, SO42- were 0.005, 0.011, 0.002, 0.11, 1.765, 0.111, 0.207, respectively. Thus, the programs such as water resources management and announcement of banned situation for the plain should be applied to improve the water quality over time.This study is a cross-sectional descriptive study. The studied area is a part of the Shiraz plain with an area of 278 hectares, where the wells supplying the city's water are located. There are 22 active drinking water wells in this area, which are mostly located in the urban context. In this study, the parameters of sodium, chloride, nitrate, sulfate, hardness, total dissolved solids and pH were investigated as parameters of resource quality indicators listed in the guidelines book of the World Health Organization. These parameters can affect the taste, smell, and appearance and generally acceptability of water.

During the sampling period, the average HQ index values for Ca2+, Mg2+, K+, Na+, Cl-, HCO32-, SO42- were 0.005, 0.011, 0.002, 0.11, 1.765, 0.111, 0.207, respectively. To investigate the spatial variations of groundwater quality in respect of drinking, agricultural and industrial water uses, various studies have been done across Iran based on the Schuller and the Wilcox diagrams and the Langelier Saturation Index. The results of the present study were in good agreement with the studies carried out by Jafari and Bakhshandehro (2014) in Isfahan Province, Rostamzadeh et al. (2015) in the Hastijan Plain, Mohammadyari and Basiri (2017) in the arid areas of Mehran and Dehloran, and Rafi Sharif et al. (2017) in the Yazd-Ardakan Plain. Therefore, considering the low quality of the groundwater, especially in the around wells, it is suggested that, in addition to prohibition of drilling new wells, the amount of water discharge from the aquifers is managed. Regarding the reduction of surface water input to the region in the recent years and the increase of pressure on the plain’s aquifer, the farming type must be changed based on detailed studies and the salt resistant crops needing less water should be developed. To manage the water resources, the qualitative and quantitative maps of the region’s water should be prepared and analyzed using the modern and precise geo-statistical methods once every couple of years. The capability of increasing the efficiency of water use in agriculture was not fully implemented. It is recommended to carry out applied and basic studies for producing aridity-tolerant and salt resistant crops and inventing irrigation methods and technics compatible with the region’s current conditions. It must be cared that the application of new irrigation technologies is consistent with the climatic and agricultural conditions. The data of this study showed that one of the issues of the available water resources in Shiraz plain was the high amount of their salt and soluble materials indicating the significant impact of the geological formations (evaporates, shales, carbonates) and the salt domes on the groundwater resources and reduction of their quality. Thus, the ongoing programs such as announcement of banned plains must be continued to improve the water quality over time.

The results of the study indicated that the water resources of the study area were within the range of waters with completely hard origin. Generally, the increase of salts and soluble materials in water results in the reduction of groundwater quality. The chemical quality type of the aquifer’s water samples was of bicarbonate and sulfate type and their facies was calcic.According to the Schuller diagram, 11 wells of the region (37%) classified as good and acceptable in respect of drinking and were potable. Only two wells (7%) classified in the average group and the remaining 16 wells (55%) were in inappropriate, completely inappropriate and non-potable groups. Considering agriculture, the Wilcox diagram showed that 24% of the Plain’s wells classified as good to permissible and 14% were in the permissible to doubtful group (farming salt resistant crops).Meanwhile, most of the region’s wells (62%) classified as unsuitable for agriculture. Considering the Langelier Saturation Index, 76% of the aquifer’s wells were in the scale-forming category and the remaining ones were in the corrosive category in the industrial respect. Although, the government has made some efforts to constrain groundwater level drop in the context of various projects, but they were not sufficient. Most of the works carried out in the banned plains, were physical, structural and supply management actions, while it might be addressed by the demand management. Since the available water resources are limited and the final cost of water discharge increases, it is necessary to encourage the users to allocate water to the plans with the maximum efficiency per one unit of water. Analysis of the all-over cost of the user’s plans is critical for their comparison and prioritization. Considering the above discussions, some recommendations are given in the following sections to reduce excessive discharge of groundwater.

In recent years, the indiscriminate withdrawal of water from aquifers in the south of Iran and the unprincipled disposal of municipal sewage and agricultural wastewater in receiving water bodies have caused a decrease in the quality of groundwater in most of these plains. The limited nature of these underground resources and their excessive use has created problems in Iran. Therefore, it is necessary to determine the chemical, physical, and biological qualitative characteristics of groundwater to specify the appropriateness of water for the intended use (Sedaghat, 2008). Various studies have been conducted in the field of groundwater quality and the effect of different factors on it. In a research, the evaluation, modeling, and zoning of groundwater quality in the Kashan Plain region were conducted using geostatistics and deterministic models. Five water quality parameters to determine the irrigation index and drinking water quality were determined using the Wilcox diagram. The final map showed that the groundwater quality increased from north to south of the studied area (Feizi et al. 2019). According to the research conducted in Saveh county, Kashan aquifer, and Zahedan plain using different groundwater quality indices, the high concentration of ions and high EC values indicates the unsuitability or problematic use of groundwater resources. Therefore, the main objectives of this research include (1) the use of hydrogeochemical and graphical methods to determine the factors affecting the groundwater quality in Fasarud plain (Darab county), (2) the use of different parameters, diagrams, and indices such as electrical conductivity, sodium adsorption ratio, soluble sodium percentage, magnesium ratio, corrosiveness ratio, and permeability index for classifying water for irrigation, and (3) comparing the chemical parameters of water samples with the guidelines of the World Health Organization (WHO) and the use of Schoeller's diagram for the classification of drinking water for the study area.

This research investigated the groundwater quality in the Fasarud plain of Darab County, where wells are mainly used for irrigation and in some places for drinking, using quality parameters and indices. Darab County is located in the southeast of Fars province and a has range of 54o 11’ to 54o 47’ east longitude and 28o 33’ to 28o 49’ north latitude at a distance of 250 km from Shiraz. The total area of the studied area is 6500 km2 with an altitude of 1180 m. According to the De Martonne index, the climate of this county is semi-arid, the average annual temperature is about 25 Co, the average annual rainfall is 350 mm, the average annual wind speed is about 1.2 m/s, the average annual potential evapotranspiration is about 1821 mm, and the average annual sunshine is about 9.4 hours per day (Bahrami et al., 2020). In this regard, the results of a period of chemical analysis related to 31 wells in March 2018 were used. Electrical conductivity, sodium absorption ratio, sodium percentage, magnesium ratio, corrosion ratio, and permeability index were used to classify water for irrigation.

A relatively wide range of changes in electrical conductivity was observed in the studied area with the lowest amount (394 μmho/cm) in well No. 22 and the highest amount (5544 μmho/cm) in well No. 24. The electrical conductivity in most of the wells is in the good and acceptable category, one well is in the cautious use class, and three wells are in the unacceptable category. Irrigation of soil with high electrical conductivity can increase the concentration of soil salts, and due to its cumulative property in the soil, it damages agricultural lands and agricultural products. Considering that the water quality in most samples is good and acceptable for agriculture in terms of salinity hazards, there is no need to amend the soil after using the water. The results showed that 39% of the groundwater samples were in the good range, 48% in the average range, and 13% in the unsuitable water range for irrigation. A comparison of the average values of qualitative parameters with the permissible values of standards 1053 of Iran and the World Health Organization showed that the average concentration of Ca, Mg, Na, SO4, and Cl ions are within the permissible range for drinking purposes, while the mean of K, HCO3, and NO3 was more than the allowed values of both standards, which indicates the entry of pollutants into the unground water of this plain through agricultural runoff and domestic sewage. Agricultural runoff has a great effect on degrading the groundwater quality, which is more effective in hot and dry areas. Also, evaporation from these solute-containing wastewater causes the solutes to be left in the upper layer of the soil during infiltration into the ground and transferred to the groundwater with subsequent irrigation or rainfall. The concentration of carbonates in natural waters is more dependent on the amount of dissolved carbon dioxide, temperature, pH, cations, and some soluble salts, which are more concentrated in groundwaters than in surface waters. Also, the comparison of each of the 31 wells' water quality studied in this plain with the Schoeller's standards showed that the water in 19 wells is acceptable or permissible for drinking, seven wells are relatively suitable, five wells are unsuitable, and the hardness in 30 wells are less than 50 mg/L. In general, the results reveal that the water in most of the wells in the study area is suitable for drinking and only the water of five wells is unsuitable due to the higher amount of some elements compared to the permissible limit of the national standard and WHO, which the contaminant has entered groundwater through agricultural wastewater.

The results showed that 58 percent of the samples are in the excellent, good, and acceptable ranges for agriculture, and in other wells, at least one of the indices is in unacceptable or cautious use classes. Also, the water of 26 wells can be used for drinking and the hardness of 30 wells is less than 50 mg/L. It is suggested to continuously monitor the groundwater resources in the study area, taking into account the existing potential of water resource pollution, including the excessive use of nitrogen fertilizers for the fertility of agricultural lands within the limits of these resources.

Application of oxygen releasing compounds (ORCs) is considered as a novel method in petroleum hydrocarbon remediation from groundwater. ORCs destroy chemically the contaminant by exposure to water which results in hydroxyl radical generation or biologically remove the pollution by biostimulation of the groundwater native microorganisms aerobically. In the present study, calcium peroxide (CaO2) nanoparticles were applied to supply the required oxygen for growth and activity of the native microorganisms to consume naphthalene (20 ppm) as a carbon source. Additionally, the effect of CaO2 content, temperature and pH on the performance of nanoparticles were investigated in the naphthalene removal. The results indicated that the microbial population was sharply increased in the presence of 400 mg/L of nanoparticles and at 30oC and the contaminant was completely removed after 20 days at neutral pH. Furthermore, naphthalene was 100% remediated from groundwater at pH 3, 7.4 and 12 after 2, 20 and 30 days, respectively. This proved the acceleration of chemical oxidation under the acidic condition. At 15 and 30 ± 0.5 oC the contaminant was removed from the media within 15 and 20 days respectively. Meanwhile, only 75% of contaminant was remediated from groundwater within 30 days at 4 ±0.5oC which was due to the reduction in the biological activity and the chemical reaction rate.

Groundwater is the most important source of fresh water in the world. Drinking water for two billion people is supplied directly from groundwater and is used to irrigate the world's largest food supply. Improper harvesting of groundwater reservoirs has led to the fact that the amount of feeder feed is not responsive to harvesting and the groundwater level has dropped. The drop in groundwater levels has led to problems such as drying up water wells, declining river and lake discharge, lowering water quality, increasing pumping costs and water extraction and land subsidence. Awareness of water level changes is necessary to understand the status of groundwater aquifers and their optimal management. By assessing groundwater level fluctuations, it can be used to manage water resources. One of the major applications of remote sensing is the detection and determination of land use changes. Using remote sensing, it is possible to study and identify various phenomena. The aim of this study was to investigate the effect of different land use on groundwater using interpolation geostatistical methods as well as object-oriented classification methods for land usemapping.

area of study Azarshahr city is located in East Azarbaijan province, located in the northwest of Iran, with an area of 840 square kilometers, 30 kilometers southwest of Tabriz, and its altitude is 1340 meters above sea level. This city is bordered by Osko city from the north and east, Urmia Lake from the west and Ajabshir city from the south. The average annual rainfall is 329 mm. Knowing the ratio of uses and how it changes over time is one of the most important things in planning and policy making. For this reason, in this study, in the first step, in order to classify and then examine the changes that occurred in a specific period of time in Azarshahr city. Therefore, in this research, in the first stage, in order to classify and record changes in a period of 20 years, object-oriented images were classified in eCognition software and output maps were extracted in ArcGIS10.5 software. (Figure 3). The classification accuracy in 2000 has an overall accuracy of 0.90 and a kappa coefficient of 0.87. While the classification in 2020 with overall accuracy of 92% and kappa coefficient of 0.90 has provided relatively higher accuracy.

Knowing the ratio of uses and how it changes over time is one of the most important things in planning and policy making. For this reason, in this study, in the first step, in order to classify and then examine the changes that occurred in a specific period of time in Azarshahr city. Therefore, in this research, in the first stage, in order to classify and record changes in a period of 20 years, object-oriented images were classified in eCognition software and output maps were extracted in ArcGIS10.5 software. (Figure 3). The classification accuracy in 2000 has an overall accuracy of 0.90 and a kappa coefficient of 0.87. While the classification in 2020 with overall accuracy of 92% and kappa coefficient of 0.90 has provided relatively higher accuracy. 

The highest rate of changes related to gardens to residential area with the amount of 2529 and conversion of use of gardens to pastures with the amount of 2126, conversion of pastures to residential with an area of 2067 hectares. Among the altered uses, the use of mountains and salt marshes has the least change, while the rate of change of use of gardens to other uses is much higher, and this also indicates the speed of destruction of gardens compared to the rate of its restoration. Also, the least changes related to the coastal area to rangeland with an area of 9, rangeland to gardens with an area of 27, coastal area to salt marshes with an area of 175 are included as the least changes of uses. In almost all land uses, the rate of conversion to residential areas has been significant, which indicates urban development as well as human interference and destruction of natural resources. According to the values of Table 5, the best model in GS + environment in order to monitor the groundwater level, the groundwater level map of the study area for both years with the method of kriging models shows the results of high accuracy. The K-Bessel method for 2000 and the circular method for 2020 were extracted, which were identified as the most accurate methods. Statistical characteristics of groundwater level with land use The highest average water level in 2000 was recorded for garden use with 13.74 meters and the lowest average water level was recorded for the coastal area of 8.41 meters. Considering the land use map and groundwater level map of 2020, the highest average water level in this year belongs to the coastal area with 9.38 meters and the lowest average recorded water level is related to the use of gardens with 6.65 meters. It can be attributed to the over-extraction of groundwater for garden crops that need more irrigation. Also, the residential area with 6.75 has the lowest recorded average. As can be seen from Tables 5 and 6, if we compare the water level of both years related to the study area, it is inferred that the average land use area of the coastal area in 2000 was 8.41, which in 2020 is 38.38. 9 It has been estimated that there has been an increase in the water level, which has increased the groundwater level and also increased the volume of water in the rivers of the region. Rangeland use also decreased significantly in 2020 compared to 2000 and decreased from 11.23 to 7.28, which indicates the critical situation of groundwater and excessive use of these resources. Water levels have been depleted, which has accelerated the destruction of these resources and will lead to horrific hazards, the most important of which is the issue of land subsidence.

The purpose of this paper is to investigate the analysis and analysis of groundwater quality factors in Farashband region for agriculture and drinking so that by using the drawing methods available in AQQA software, it is possible to provide a suitable solution for plain management. In this study, 19 villages from Farashband city in Fars province were selected and physicochemical parameters along with quantitative changes in groundwater resources were analyzed during 2016. The results showed that, based on the Wilcox diagram in 1995, the southern region is the source and the owner of the C3S1 class with salt water and can be used for agriculture. The rest of the C4S1 and C4S2 class areas are of very poor quality for unsuitable agriculture. In the classification of the quality of Farashband groundwater for agriculture based on WHO, it was found that about 56.2% of groundwater in Farashband region has a relatively favorable quality for agriculture. The groundwater of the region according to the Iranian standard for drinking determined that all the groundwater of Farashband region has good and permitted quality based on the amount of acidity, the amount of sulfate and the amount of hardness for drinking; However,

Because of the high groundwater level available in Guilan plain and the possibility of contamination of groundwater due to leachate from urban landfills, in this study, the quality of groundwater in 9 wells in the southern area of the landfill of Rasht was examined and the concentration of COD, TN, TP, TDS, EC, and other input of used methods were analyzed. In order to investigate the spatial and temporal changes in groundwater quality in the study area, the qualitative parameters used in terms of drinking and agriculture purposes in Schuler and Wilcox classifications were zoned into two dry and wet seasons using Geographic Information System. The results showed that groundwater quality in this area is good and acceptable for drinking based on Schuler classification and good and acceptable for agricultural purposes based on Wilcox classification. Comparison of zoning maps showed that all parameters in the wet season have decreased in the direction of groundwater flow. Also, the results showed that the landfill of Rasht has no effect on groundwater quality in the study area and it is most likely that the leachate flow is aligned with the flow of the surface leachate to the north and northwest.

The aim of this study was to determine the impact of high concentration of fluoride in drinking water on dental fluorosis by using the optimal dose of fluorine and its intake in different age groups. To assess the relationship between fluoride concentrations in drinking water and the incidence of fluorosis in study area, 19 groundwater samples as well as 19 soil samples have been collected to measure the fluoride content and acidity of soil respectively. The concentrations of fluoride of 42% water samples were higher than value recommended by World Health Organization. The optimal amount of fluoride in groundwater for study area is 0.71 mg/L. The estimated fluoride intake from drinking water is in the three age groups of adults, children and infants is 0.03, 0.09 and 0.21. However the minimum risk of 0.05 mg per kg per day calculated by Agency for Toxic Substances and Disease Registry. The optimal amount of fluoride in groundwater for study area is 0.71 mg/L. The estimated fluoride intake from drinking water is in the three age groups of adults, children and infants is 0.03, 0.09 and 0.21.

Iodine is an essential micronutrient for human health, hence iodine deficiency causes various damages such as thyroid disorders. Climate and geological settings are the causes of the incidence and prevalence of the mentioned disorder. A bibliographic survey showed that no studies have been undertaken so far in this area with regard to geological setting, so in this research we focused on geological reason(s) with investigation on soil and water. In response to reports on the high incidence of iodine disorders in Dehdasht area, 16 ground water samples were taken from agricultural wells, drinking water and springs in the area to analyze anions, cations and iodine. The results showed that iodine levels were high in some water samples. To study the effect of soil on iodine, 20 soil samples were taken from various formations and pH, iodine as well as organic matter were measured. iodine can exist in several species. In different environments, the mobility of iodine depends on the type of iodine.The results showed that due to the presence of calcareous formations, high pH and calcium can lead to low mobility of iodine Also the alkaline and reduction conditions, can cause high mobility and enrichment of iodine in groundwater.