Saline Water Sources Research Articles

Influence of saline water sources on the crystallographic and morphological criteria of organic-template-free eco-synthesized zeolites

Influence of saline water sources on the crystallographic and morphological criteria of organic-template-free eco-synthesized zeolites

LARGE-SCALE LANDSLIDES DUE TO SALINE WATER PLUME INTRUSION - AN EXAMPLE OF THE OKIMI LANDSLIDE IN NIIGATA PREFECTURE, JAPAN

Large-scale landslides with volumes ranging from tens to hundreds of millions of m3 are scattered throughout Niigata Prefecture, Japan. There is no accepted theory, although many researchers have argued about the mechanism of these landslides. Highly concentrated Na-Cl type groundwater (hereafter called "saline water") has often been found in large-scale landslides in Niigata Prefecture. In addition, the observation wells where saline water occurs are sometimes flowing wells. We also pay special attention to the distribution of landslide-prone areas and oil and gas fields in Niigata Prefecture, which generally overlap, and saline water from landslides is originally fossil seawater such as oil-brine based on geochemical characteristics. On the other hand, anomalous high-pressure reservoirs at depths of more than 1,000 m in oil and gas fields have been known since the 1960s and are possible saline water sources. We believe saline water's behavior is key to better understanding the mechanism of large-scale landslides. The Okimi landslide, this research area, is located in the Kamiya area, Joetsu City, western part of Niigata Prefecture, Japan. The aspect of the active body is about 500 m wide and 1,500 m long, with an area of about 70 ha. The bedrock geology is mainly Neogene unconsolidated mudstone. According to previous studies, saline water has been detected in observation wells at the head of this landslide. Since the geological formation containing saline water has a considerably low resistivity value (≤ 2.0 Ωm), the CSMT method is best suited for electromagnetic exploration to visualize the resistivity up to 1,000 m depth. The survey results confirm the existence of a saline water plume rising from a "saline water chamber" located 100 to 300 m below the western side of this landslide to the bottom of this landslide (at a depth of about 30 m). The presence of the saline water plume suggests that the upwelling of saline water from the anomalous high-pressure reservoir (saline water chamber) is closely related to several large-scale landslides.

Effect of electron acceptors on electricity production and desalination of caspian sea water using microbial desalination cells

ABSTRACT The Microbial Desalination Cell (MDC) stands out as an innovative and a sustainable technology for both renewable energy generation and water treatment. The choice of electron acceptor significantly influences the efficiency of electricity flow. This study focuses on exploring the MDC performance under different conditions, including variations in cathode electron acceptors, initial pH levels, and hydraulic retention time (HRT). The investigation assesses simultaneous reduction of TDS and power generation from Caspian Sea water, a prominent saline water source in northern Iran, in both open-circuit (OC) and closed-circuit (CC) modes. The findings reveal that sodium hypochlorite, potassium permanganate, and potassium bromate as catholyte achieved TDS reduction rates of 84%, 77%, and 72%, respectively, under CC conditions at pH 5. Furthermore, it was observed that increasing HRT and pH levels lead to a decrease in desalination efficiency and power generation. Notably, the study highlights that the maximum power density was attained using permanganate, hypochlorite, and bromate as catholyte in both OC and CC configurations. By showcasing the adaptability of MDC performance with different cathode electron acceptors under varying conditions, this research offers valuable insights for optimizing MDC efficiency when treating real saline water sources.

Maximizing water recovery from reverse osmosis for agricultural brine reuse in Kenya

Water-stressed regions like Kenya rely on saline water sources, which can pose serious health hazards if not treated. While desalination is a burgeoning solution, safe disposal of desalination brine is often infeasible or too expensive. To circumvent this disposal challenge, we examine the maximum desalination recovery ratio (RRmax) for which desalination brine can safely be reused for many agricultural applications. Water samples from the Mara Triangle and data from past studies were collected and analyzed to measure contaminant concentrations against established safety limits of salinity and potentially hazardous elements for multiple agricultural use cases. The results suggest that high water recoveries were possible in the Mara Triangle, with the maximum recovery ratio reaching greater than 94% and 98% for crop irrigation and livestock watering, respectively. Brine reuse in this region was mostly limited by salinity, with Boron content ranking second. The most salt-tolerant crops (i.e., barley, sorghum, and wheat) were shown to be cultivable in all locations. According to calculations of the Heavy Metal Evaluation Index, groundwater in the Mara Triangle was generally safer for direct use by all users than the surface waters sampled in the past Lake Victoria and Nairobi studies.

Aquatic Insects Communities in a Saline Water Source - Antofagasta, Chile

The aquatic insects include mainly larval stages, that hatch into adults, as occurring in some Diptera, which can generate problems in human health in tropical regions as these can transmit diseases. Some of these are reported from inland and coastal saline waters. The present study is an attept to apply the null models to explain the structure of aquatic insects a small saline water source located at south of Antofagasta town (23°47’ S, Chile), using species associations and niches sharing null models. The results reveal a low taxa number, specifically of Diptera (Ephydridae, Ceratopogonidae and Nematocera). The null models of species associations reveal that the associations are random. Evaluation of the niche sharing reveal that species share ecological niches, and as a consequence there are interspecific competition. The reported taxa are similar with communities for inland water saline ecosystems as far as community structure and taxonomic groups are concerned.

Modeling gypsum (calcium sulfate dihydrate) solubility in aqueous electrolyte solutions using extreme learning machine

Due to various operational conditions, experimental determination of gypsum solubility in water-based systems comprising multiple ionic compounds is often impractical or costly. In this regard, computer-based intelligent approaches can provide highly effective and economical alternatives. In this study, after providing a database with 2288 experimental data-points gathered from 31 various literatures, four advanced artificial intelligence techniques were developed: Adaptive Boosting-Support Vector Regression (AdaBoost-SVR), Extreme Learning Machine (ELM), Gradient Boosting-Support Vector Regression (GB-SVR), and Multivariate Adaptive Regression Splines (MARS). The aim of these techniques was to predict the gypsum solubility in aqueous electrolyte solutions as a function of the solutions' temperature and 22 distinct salts' Molal concentrations. After performing various statistical and graphical analyses, it was observed that the ELM model has a more accurate prediction capability for gypsum solubility in aqueous electrolyte solutions compared to the other three models. For this model, the highest Coefficient of Determination (R2 = 0.9926) and the lowest Root Mean Square Error (RMSE = 0.00373) were obtained. Furthermore, after conducting a sensitivity analysis to calculate the relevancy factors of the ELM model's input and output variables, the variation trend of gypsum solubility was evaluated. According to the multiple evaluations, the ELM model predictions reasonably agreed with the experimental data on gypsum solubility in the chosen solutions and temperature ranges. The ELM model can be implemented in numerical modeling frameworks for improving the treatment and reclamation operations of saline water sources, optimizing the oil and gas recovery and production processes, and controlling the complicated geotechnical issues.

Evaluating topsoil salinity via geophysical methods in rice production systems in the Vietnam Mekong Delta

AbstractThe Vietnam Mekong Delta (VMD) is threatened by increasing saltwater intrusion due to diminishing freshwater availability, land subsidence, and climate change induced sea level rise. Through irrigation, saltwater can accumulate in the rice fields and decrease rice production. The study aims at evaluating topsoil salinity and examining a potential link between topsoil salinity and rice production systems in a case study in the Tra Vinh province of the VMD. For this, we applied two geophysical methods, namely, 3D electrical resistivity tomography (ARES II) and electromagnetic induction (EM38‐MK2). 3D ARES II measurements with different electrode spacings were compared with EM38‐MK2 topsoil measurements to evaluate their respective potential for monitoring topsoil salinity on an agricultural scale and the relationship between land‐use types and topsoil salinity. Results show that EM38‐MK2 is a rapid and powerful tool for obtaining high‐resolution topsoil salinity maps for rice fields. With ARES II data, 3D maps up to 40 m depth can be created, but compared with EM38‐MK2 topsoil maps, topsoil salinity was underestimated due to limitations in resolution. Salt contamination of above 300 mS m−1 was found in some double‐cropped rice fields, whereas in triple‐cropped rice fields salinity was below 200 mS m−1. Results clearly show a relation between topsoil salinity and proximity to the saline water sources; however, a clear link between rice production and topsoil salinity could not be established. The study proved that geophysical methods are useful tools for assessing and monitoring topsoil salinity at agricultural fields scale in the VMD.

Effects of saline water on soil properties and red radish growth in saline soil as a function of co-applying wood chips biochar with chemical fertilizers

BackgroundCurrently, using unconventional water sources in agriculture has become necessary to face overpopulation worldwide. Therefore, a pot experiment was carried out to evaluate the effects of irrigation with saline water in the presence of co-applied wood chips biochar (WCB) with chemical fertilizers on physicochemical properties and nutrient availability as well as growth parameters, and yield of red radish (Raphanus sativus L.) grown in the saline sandy soil.MethodsThe WCB was added to the saline sandy soil at levels of 0 (control), 2.5, and 5% w/w. Then, this soil was cultivated by red radish plants and irrigated with saline water (5 dS m− 1). This experiment was performed in a randomized complete block design with three replicates.ResultsCompared with the control treatment, WCB treatments increased significantly soil water holding capacity by 34.8% and 73.2% for levels of 2.5 and 5%, respectively. Soil pH decreased significantly in all WCB treatments. The relative increase in the total available nitrogen over the control was 30.1 and 103.5% for 2.5 and 5% wood chips biochar, respectively. Compared to the control, applying WCB at 2.5% led to an increase in the fresh root weight of red radish plants by 142.7%, while 5% caused a decrease in the fresh root weight of red radish plants by 29.4%.ConclusionRecently, WCB represents an interesting approach to the rehabilitation of saline soils and the management of using saline water sources. It is recommended that combined application of WCB at a level of 2.5% with chemical fertilizers in order to improve red radish growth and nutrient retention in the saline sandy soil which preserves the ecosystem as well as increases productivity leading to the reduction of costs.

Prediction of alkaline earth metal ion adsorption on goethite for various background electrolytes with the CD-MUSIC model

As water scarcity drives the use of more saline water sources, contaminant fate and transport models must capture the impact of high concentrations of alkaline earth metal ions (AEMs) and background electrolytes in these more complex waters. By utilizing macroscopic adsorption data from various electrolyte systems, a Charge Distribution – Multisite Complexation (CD-MUSIC) model, capable of incorporating electrolyte adsorption, was able to accurately simulate the adsorption behavior of alkaline earth metal ions onto goethite. The modeling effort was guided by previous spectroscopic and surface complexation modeling of alkaline earth metal adsorption and built on previous CD-MUSIC modeling that accounted for changes in crystal face contributions to the surface site density as a function of specific surface area. The model was constrained to consider only two dominant surface complex species for each metal ion adsorption reaction. These two species were selected from 44 possible species through objective curve fitting of single-solute macroscopic adsorption data. While most of the alkaline earth metal surface complexes formed outer-sphere complexes at the goethite surface, an inner-sphere species was utilized for Mg2+. With the surface complex species and equilibrium constants obtained from this study, the calibrated model successfully predicted alkaline earth metal ion adsorption over a wide range of solution and surface conditions; the model predictions encompassed a wide range of pH (5–11), solute/solid ratio (1.37 × 10−5– 8.33 × 10−4 mol-solute/g-solid), ionic strengths (0.01 M – 0.7 M), and background electrolytes (Na+, Cs+, Rb+, Cl−, and NO3−) using the same crystal face contribution methodology for site density, capacitance values, and surface acidity constants adopted for proton and cadmium adsorption in previous work (Han and Katz, 2019). Model simulations for a range of background water chemistries demonstrated the potential for Mg2+ to reduce Cd2+ adsorption to goethite in model seawater and oil- and gas-produced waters.

Using of saltwater to increase the output power of a steam injected gas turbine (STIG) by connecting spray freezing desalination to it

Gas turbines are one of the common methods for generating electrical energy. However, reducing the output power by increasing the air temperature is one of the problems of these turbines. Common methods to compensate for the power drop of gas turbines are often based on turbine inlet air cooling (TIAC) technology or injecting steam or water into the turbine as humidified gas turbine (HGT) that causes an increase in its output power. However, these technologies often require high consumption of fresh water which limits their use in dry and low-water areas. Therefore this study has investigated the connection of a spray freezing desalination to a steam-injected gas turbine (STIG) through a reverse Brayton cycle for increasing its output power by consuming saltwater. This spray freezing desalination is a process based on eutectic freeze crystallization (EFC) technology that uses compressed air in a turbo expander to produce chilled air that can crystallize the droplet of sprayed saline water. This desalination technology has the potential of zero liquid discharge (ZLD). Therefore, with the possibility of using a saline water source such as reverse osmosis (RO) brine in this process, in addition to increasing the output power of gas turbines, it will be possible to reduce the environmental problems related to its disposal.

Multi-criteria decision-making for selecting a solar farm location to supply energy to reverse osmosis devices and produce freshwater using GIS in Iran

Iran has 985,798 square kilometers of desert areas, equivalent to 59.8 percent of the country's total area. This factor causes the creation of salt marshes and, accordingly, the salinization of surface and groundwater. For the first time in this paper, an indirect method is presented to identify areas of Brackish water sources with 3000–10000 mg/L TDS in the entire country of Iran and simultaneously identify the area's potential in terms of the solar energy to provide energy for desalination by reverse osmosis devices. Other types of sources of water, such as seawater, which has more salinity than Brackish water (about 35000 mg/liter) are not investigated in this research, because the primary purpose of this article is to use water that exists in the form of ponds, wells, or surface water that water cannot be used for residential or agricultural purposes, at the same time, this water is not seawater. Simultaneously 16 data layers that include economic, environmental, technical, and geological parameters have been considered.The proposed methodology provides a structured decision aid, which can be used in other countries to identify the mentioned areas and produce fresh water using reverse osmosis devices. Geographic Information Systems (GIS) are used to generate layers of data and to apply the elimination criteria and constraints. Multiple Criteria Decision Analysis (MCDA) is then used to rank and sort the grids via the identified evaluation criteria. This research can also have two other applications. The first is for professionals who want to identify areas with saline water potential, and the second is for organizations that want to launch reverse osmosis desalination plants that work with solar renewable energy. Technically, there are about 160 cities in Iran that have an area of about 144440685120.498077 square meters, have saline water sources, and simultaneously have the potential to use solar energy as one of the renewable energy sources to power reverse osmosis desalination devices. Most of these areas are located in the east of Iran and these areas have high water stress. In this research, the city of Khansar with an area of 95917147.16 square meters, which is located in the province of Isfahan and in the central part of Iran, has surface and underground saline water resources that both technically and operationally, has the highest potential.

Brackish-water desalination plant modulates ground deformation in the city of Cape Coral, Florida

The groundwater abstraction and injection cycle in coastal aquifer systems can locally change the piezometric head in aquifer system, leading to differential settlement on the ground that may compromise infrastructure safety. Furthermore, long-term, extensive groundwater extraction may cause significant damage to water resources. Ironically, Florida, a state known for its abundant water resources, has been experiencing major water supply issues in some areas that began to intensify with rapid population growth over the last five decades. As the demand for drinking water in Florida continues to rise, local authorities have turned to using brackish and saline water sources. As of 2022, more than 80% of the desalination plants in the United States are concentrated in the coastal areas of central and south Florida. Using satellite radar interferometry, we have investigated the spatiotemporal evolution of surface subsidence driven by groundwater pumping for brackish-water reverse osmosis (BWRO) desalination facilities in the City of Cape Coral, Florida. We employed Persistent Scatterer Interferometry (PSI) to process all available Sentinel 1A and 1B scenes over the region along two ascending orbits. The deformation time-series obtained from independent SAR data sets are compared spatiotemporally with the groundwater level that provides feed water to the BWRO facilities. The deformation pattern shows one main lobe of subsidence with rates of up to 25 mm/year centred around the operating wells in the north BWRO wellfield that we interpret as human-induced compaction. The spatial correlation between the subsiding area and the active production wells argues in favour of surface deformation induced by the BWRO operations. Based on the InSAR-derived displacement field and well data, we propose a model to explain the spatial heterogeneity of the subsidence process. The ground deformation is reproduced by an elastic model mimicking the reservoir compaction using planar negative closing dislocations. Modelling of the subsidence shows ∼ 0.67 Mm3 yr−1 vol loss due to compaction of the aquifer. The subsidence deformation was also used to compute the cumulative drainage area of the producing wells.

Energy from Salinity Gradient of Wetland Saline Water Using Reverse Electrodialysis Membrane

Reverse electrodialysis (RED) membrane is an emerging renewable energy which harvest electricity from mixing two streams on different salinities. In real practice is still not clearly defined for the effectiveness of salinity gradient power (SGP)-RED due to the limitation of artificial saline water. Generally, South Kalimantan Indonesia is rich by wetland and coastal area. Due to that wetland saline water is potential as saline water sources for collection the SGP. This experiment aims to investigate the impact of natural feed stream wetland saline water was collected from Muara Halayung South Kalimantan-Indonesia to demineralized (WSW),artificial brackish (ABW) (0.35 wt %NaCl), and artificial seawater (ASW) (3.5 wt % NaCl) in terms of power density measured on a lab-scale RED membrane stack prototype 12 x 12 cm. Ion exchange membrane (IEM) was used in this work consisted from cellulose modified Anion Exchange Membrane (AEM) by EDTA-quaternization (EDC) process. Whereas, Cation Exchange Membrane (CEM) was employing Nafion NR-212 with thickness 0.002 in. Lab-scale RED tests operated 3 hours into area system has 121cm2; AEM and CEM area have 100cm2; uses spacer nylon a pair between membranes; and two electrodes by stainless-steal and copper. Feed water was into RED system then measured power density as an electrical energy potential that from separate ions by AEM and CEM. The result among of this experiment, characteristic of wetland saline water naturally had electro conductivity (EC) 135.6 µS/cm; TOM 15.2 ppm; and has ionic compound higher in Na+ and Cl- which is Cl- compound as one of potentially formed salinity on that wetland water and become potential uses one of natural feed water in RED system. The highest energy power density on RED process obtained by mixed WSW:ASW was 1.43 W/m2. While ratio of the gradient salinity WSW:ABW to ABW:ASW were increasing 86% which has 1:5 to 1:30 as the effect of stream mixing by two natural feed water.

A complementary approach of response surface methodology and an artificial neural network for the optimization and prediction of low salinity reverse osmosis performance

The treatment of saline water sources by reverse osmosis (RO) is being utilized increasingly to address water shortages around the world. The application of RO is energy-intensive; therefore, plant and process optimization are crucial. The desalination of low salinity water sources with total dissolved solids (TDS) of <5000 mg/L is less energy intensive than the desalination of highly saline seawater and brackish water. A gap exists in optimization studies on lower salinity water (TDS = 500–5000 mg/L). The novelty of the study is the development of a complementary approach using response surface methodology (RSM) and an artificial neural network (ANN) for performance modelling, optimization, and prediction of RO desalination of low salinity water. Feed water salinity, pressure, and temperature were controlled variables to model the performance of the RO system. A performance index incorporating salt rejection efficiency and permeate flux was used as the response target of the system. The optimal parameter combination within their modelled range for the best performance index occurred near the highest pressure input of 150.57 psi, at the temperature of 38.8 °C, and at the lowest feed salt concentration of 577 mg/L. Both the RSM and ANN models demonstrated high validity. The RSM and ANN showed R2 values of 0.99 each and with a root mean square error of 2.41 and 5.85 respectively. The RSM showed a small benefit in model accuracy over the ANN, but the ANN has the benefit of not requiring the central composite design before experimentation and being a continuously improving prediction method as more data becomes available. Further applications of the optimization and modelling approach can be applied to RO system optimization considering membrane types and additional feedwater characteristics.

Improving the saline water evaporation rates using highly conductive carbonaceous materials under infrared light for improved freshwater production

Because of the growing population and scarcity of limited freshwater resources, one out of three people in the world do not have access to safe drinking water today; thus, there is an urgent need to address this global concern. Desalinating sea water using renewable energy concepts can be one of the most efficient freshwater solutions for water scarcity issues. We hypothesized that the freshwater scarcity problem could be addressed using effective desalination processes associated with renewable energy and highly porous materials. The primary objective of this study is to investigate the capability of enhancing the saline water evaporation rates using thermally and electrically conductive carbonaceous materials. This study used commercially available carbon felt, woven carbon fiber fabrics, and carbon fiber reinforced composites (60% carbon fiber) to evaporate the saline water with different percentages of salt concentrations. Tap water (or 0 wt% water), 1.5 wt% saline water, and 3.0 wt% saline water sources were prepared and used in the saline water desalination process under simulated solar infrared (IR) light with a power of 250 W. The test results exhibited that the carbon felt water evaporation rate was about 5.37 kg m−2 h−1 with a water temperature of 97.9 °C for 3.0 wt% saline water, which is 32% greater than the base cases and considerably higher than other selected carbonaceous materials. Here, 3.0 wt% saline water represents the average salt concentration of the earth's ocean water, and the high surface area carbon felt seems an effective solar-driven water evaporator for this water. This research provides the potential to deliberate highly durable carbon materials for future freshwater production.

A Neural Network Based Superstructure Optimization Approach to Reverse Osmosis Desalination Plants.

An ever-growing population together with globally depleting water resources pose immense stresses for water supply systems. Desalination technologies can reduce these stresses by generating fresh water from saline water sources. Reverse osmosis (RO), as the industry leading desalination technology, typically involves a complex network of membrane modules that separate unwanted particles from water. The optimal design and operation of these complex RO systems can be computationally expensive. In this work, we present a modeling and optimization strategy for addressing the optimal operation of an industrial-scale RO plant. We employ a feed-forward artificial neural network (ANN) surrogate modeling representation with rectified linear units as activation functions to capture the membrane behavior accurately. Several ANN set-ups and surrogate models are presented and evaluated, based on collected data from the HOaks RO desalination plant in South-Central Texas. The developed ANN is then transformed into a mixed-integer linear programming formulation for the purpose of minimizing energy consumption while maximizing water utilization. Trade-offs between the two competing objectives are visualized in a Pareto front, where indirect savings can be uncovered by comparing energy consumption for an array of water recoveries and feed flows.

Comprehensive analysis of design software application in solar distillation units

The use of solar stills in rural regions are becoming increasingly popular as it is an economical solution for drinking water from saline water sources. Many researchers have worked for the improvement of conventional solar still to enhance productivity. Costly and time-consuming processes of operation in solar stills encourage many scholars to analyze mathematical simulation. This paper presents comprehensive reviews of the application of different design software to solar still systems. Design software is essential for developing and analyzing the mathematical models and predicting the most suitable performance parameters for the enhanced production rate of distilled water for still systems. Numerical modeling of solar still systems is necessary to analyze and investigate air movement, temperature variation for knowing water temperature, and air temperature through software like CFD, MATLAB, FORTRAN, TRYNSYS AutoCAD. The simulation technique's application using CFD is made with TRNSYS, FLUENT, ANSYS, FORTRAN and MATLAB which are useful tools to develop such mathematical models for the prediction of flow parameters. Engineering Equation Solver (EES) package and COMSOL Multiphysics solve the differential energy balance equation. All newly developed software employed for the utility of still solar systems is discussed. This article provides a comprehensive overview of the various software tools used in solar still to help researchers, scientists, and academicians.

Isotopic signatures to address the groundwater recharge in coastal aquifers

The dynamics of the coastal aquifers are well-expressed by geochemical and isotopic signatures. Coastal regions often exhibit complex groundwater recharge pattern due to the influence of depression in the Bay of Bengal, tidal variations on surface waters, saline water intrusion and agricultural return flows. In this research, groundwater recharge processes occurring in coastal Tamil Nadu, South India were evaluated using major ion chemistry and environmental isotopes. A total of 170 groundwater samples were collected from shallow and deep aquifers during both post-monsoon (POM) and pre-monsoon (PRM) seasons. The isotopic results showed a wide variation in the shallow groundwater, suggesting contribution from multiple recharge sources. But, the deeper groundwater recharge is mainly from precipitation. The northern part of the study area showed more depleted isotopic values, which rapidly changed towards south from −6.8 to −4.4‰. Alternatively, central and southern parts exhibited relatively enriched isotopic content with variation from −0.58 to −2.7‰. Groundwater was discerned to be brackish to saline with chloride content, 600–2060 mgL−1 and δ18O ranging from −5.8 to −4.5‰, suggesting influence of the saline water sources. A minor influence of anthropogenic activities was also observed in the deeper groundwater during PRM, which was confirmed by tritium and Cl− trends. The old groundwater with depleted isotopic content infer recharged by distant sources while modern groundwater with enriched isotopes points to the influence of evaporated recharge.

بررسی تأثیر نسبت های مختلف کلسیم به منیزیم آب آبیاری بر خصوصیات رشدی و عملکرد کینوا (.Chenopodium quinoa Willd)

Introduction Quinoa (Chenopodium quinoa Willd.) is a facultative halophyte with very high adaptability to varied climatic conditions and high nutritional value. Different quinoa cultivars can have economical and stable yield in saline soil and water conditions. In addition to salinity, the chemical composition of irrigation water and thus soil solution affect the uptake and transfer of water and nutrients, and so plant yield. The intensity of this effect depends on various factors such as plant species. Calcium to magnesium ratio (Ca/Mg) is one of the quality indicators of irrigation water that can affect soil physical conditions and nutrient uptake independent of salinity level. A Ca/Mg < 1 and exchangeable magnesium percentage more than 25% in irrigation water are considered high enough to reduce soil quality and crop yields. Currently, frequent droughts and high water extraction have caused a sharp drop in water levels, increase in salinity, and in some cases a decrease in the Ca/Mg in the groundwater of most arid regions of the country. Since the effect of Ca/Mg in irrigation water on growth and yield of quinoa has not been studied so far, so the aim of this study was to investigate the effect of different Ca/Mg in irrigation water on growth parameters and quinoa grain yield in saline conditions. Materials and methods To study the effect of different Ca/Mg of irrigation water on quinoa growth and yield, three separate experiments in a randomized complete block design with four replications were conducted at the Research Greenhouse of Soil and Water Research Institute in 2018. Experimental treatments included three different Ca/Mg in irrigation water consisting of 0.25, 0.5 and 1, which were made by sodium chloride, magnesium and calcium as nutrient solutions fit to the salinity tolerance threshold of quinoa at different growth stages. In the previous research, yield reduction thresholds for Titicaca cultivar at different growth stages in a soilless culture (perlite) were a: 8 dS m-1 for emergence, b: 15 dS m-1 for flowering and c: 20 dS m-1 for grain filling. To conduct this research, 100 quinoa seeds were planted in pots, and the pots were irrigated with 8 dS m-1 water along with the desired Ca/Mg treatments. After establishing the quinoa seedlings and thinning to six plants per pot, pot irrigation was done with 15 dS m-1 salinity along with the desired treatments. After ensuring the end of the flowering stage, the remaining pots were irrigated with 20 dS m-1 salinity with the desired treatments until physiological ripening. Finally, the analysis of variance of the data was performed using SAS software and the means were compared with the protected LSD at 5% probability level. Results and discussion The results showed that the emergence percentage and non-uniformity of quinoa were not affected by Ca/Mg of irrigation water, however, increasing the magnesium amount significantly improved the emergence rate of quinoa seeds. Although the results showed that the fresh and dry weight at the flowering stage was significantly affected by Ca/Mg of irrigation water, the yield and yield components were not significantly affected. Therefore, the quinoa growth and yield are not affected by the ionic composition of irrigation water in terms of low Ca/Mg, however, the composition of absorbed and accumulated ions in plant tissues are significantly changed. So, compared to other conventional crops, quinoa has the potential to produce economic yield in saline conditions and is not affected by the Ca/Mg of water sources. Conclusion The results of this study showed that different Ca/Mg in irrigation water do not reduce the growth and yield of quinoa. Therefore, if the salinity tolerance threshold of the plant is considered, low water quality in terms of high magnesium concentration does not damage the plant and so can be cultivated with saline water sources such as diluted seawater.

A hydrochemical and remote sensing approach to decrypt the groundwater salinization in the coastal district of Sabarmati basin, Gujarat

Coastal cities worldwide are witnessing large-scale salinity both inland as well as coastal salinity, especially in semi-arid regions. The economic aspiration and changes in land use associated with the excavation of unsustainable groundwater withdrawal is leading to saline up-coning as well as seawater intrusion in the coastal aquifers. The present study has been conducted in Anand district of Gujarat, India, to evaluate the genesis of salinity in the coastal aquifers. In the current study, both conservative elements and stable isotopes are used to explain the controlling factors of groundwater salinization and its hydrogeochemical processes. LISS-IV (Linear Imaging Self-scanning) was used to map land use land cover to understand the impact of land use practices on groundwater conditions and salinity mapping. From 2006 to 2018, the surveying and mapping of saline soil showed an increasing trend, which indicates high salinity in groundwater regime and soil characteristic. The chemical constituents coming from reverse ion exchange mineral dissolution as well as anthropogenic sources of saline water are demarcated using saturation index and ionic ratio. The origin of water salinity is described using δ18O and δD, the relationship regression line below LMWL suggests significant evaporation of recharging water before infiltration.