US Salinity Laboratory Research Articles

Comparing Global Classifications of Water That Applied on Some of AL-Qadissiya Wells Water

This study has been conducted to evaluate the quality of some of AL-Qadisyah province wells water and classify them according to global classifications. Nineteen wells in different locations have been pointed and assessed during the period between September 2012 to August 2013. Results shows differences in water quality depending on the locations; Electrical conductivity ranges between 1.60 and 19.82 ds.m-1, and Sodium adsorption ratio ranges between 2.03 and 17.47. Four global classifications have been used. The US Salinity Laboratory classification of the year of 1954 categorized most of these wells in category of C4-S1, which is high-salinity and too low sodic water. According to FAO classification of the year of 1985, some of the wells categorized in category of high-salinity and some other mild to moderate salinity. The same classification of the year of 1992 puts most of the wells in moderate salinity category, and characterizes their water as water of puncture and initial groundwater. According to the suggested classification by Ghliam (1997), 73% takes place between accepted to moderated salinity. These classifications state the applicability of using wells water for agricultural purposes in this area considering; good management practices using washing requirements around 15-20%, using good drain system, reducing ground water level to maintain the balance of saline soil, and cultivating salinity tolerant crops. This study could be used as an index when underground water wanted to be used for agricultural territory of AL- Diwanyia

Hydrochemical characterization of groundwater under agricultural land in arid environment: a case study of Al-Kharj, Saudi Arabia

This study focuses on chemical analysis of 180 different groundwater samples in Al-Kharj governorate, Saudi Arabia. The distribution of chemical constituents (major, minor, and trace elements) is determined and compared with drinking and irrigation water standards. The water quality index (WQI) is applied to investigate groundwaters suitability for drinking. The obtained results indicated that the concentrations of dissolved salts, soluble cations and anions, and nitrate, were above permissible limits set by drinking water standards, WHO, for most wells. The WQI concluded that 65.2 % of studied wells are considered poor water “class (III)”, 24.9 % are very poor water “class (IV)”, 6.1 % are unsuitable water for drinking “class (V)”, and only 3.9 % are good water for drinking or “class (II). Most groundwater is contaminated with nitrate with an average concentration of 14.7 mg L−1. The water evaluation for irrigation poses that 69.4 % of studied wells are classified as moderately saline; however, the remaining are classified as severe saline water. The US Salinity Laboratory’s diagram reveals that majority of studied waters fall in class C4–S1, the area of very high salinity and low sodium hazards. Durov and Piper diagrams revealed that the majority of investigated waters are magnesium-calcium/sulfate–chloride water type. The Gibbs’s diagram revealed that the chemical weathering of rock-forming minerals and evaporation are influencing the groundwater quality. The hydrochemical modeling indicates that all water samples are undersaturated for halite and saturated for anhydrite and gypsum. The approach of this research could be applicable to similar situations worldwide.

Hydrochemical appraisal of groundwater quality for drinking and irrigation purposes and the major influencing factors: a case study in and around Hua County, China

Groundwater is the major source of water for drinking and irrigation purposes in and around Hua County, China. However, long-term industrial effluents in the upstream of the area have produced contamination to groundwater. To provide a clear and better understanding of the status and extent of groundwater pollution to local decision makers, groundwater quality was assessed for drinking and irrigation purposes in this study using sodium adsorption ratio (SAR), residual sodium carbonate (RSC), soluble sodium percentage (%Na), permeability index (PI), an entropy weighted water quality index (EWQI), and some graphical approaches such as Wilcox and US Salinity Laboratory (USSL) diagrams. Factors that have significant influences on the hydrochemistry and quality of groundwater were also discussed in detail. Finally, some measures for the protection and management of groundwater in the study area were provided to local decision makers. The results show that shallow groundwater in and around the Hua County is mainly slightly alkaline freshwater with the majority of the samples falling in the category of HCO3–Ca and mixed HCO3·SO4–Ca·Mg. Medium quality water is prevalent in the study area for drinking purpose, and the main contaminants in groundwater are total dissolved solid (TDS), total hardness (TH), SO4 2−, Cl−, NO3 −, NO2 −, and oil. Groundwater in the study area is suitable for agricultural irrigation with regard to sodium hazard, but mixing of low and high salinity water is recommended before irrigation to reduce the salinity hazard in local areas. Natural processes such as weathering of parent rocks, cation exchange, and groundwater evaporation are the dominant factors influencing groundwater chemistry in the study area. However, river water leakage and human interference are becoming increasingly important in altering natural groundwater chemistry. The recommendations suggest in this study may help to prevent further groundwater pollution in the study area, and the results and recommendations reported here will also be useful for many other regions facing similar problems.

Hydrogeochemical investigations and groundwater quality assessment of Torbat-Zaveh plain, Khorasan Razavi, Iran.

Hydrogeochemical investigations of groundwater in Torbat-Zaveh plain have been carried out to assess the water quality for drinking and irrigation purposes. In this study, 190 groundwater samples were collected and analyzed for physicochemical parameters and major ion concentrations. The abundance of major cations and anions was in the following order: Na(+) > Mg(2+) > Ca(2+) > K(+), and Cl(-) > [Formula: see text] > [Formula: see text] > [Formula: see text]. As a result, alkaline element (Na(+)) exceeds alkaline earth elements (Mg(2+) and Ca(2+)), and strong acids (Cl(-) and [Formula: see text]) dominate weak acids ([Formula: see text] and [Formula: see text]) in majority of the groundwater samples. Statistical analyses including Spearman correlation coefficients and factor analysis display good correlation between physicochemical parameters (EC, TDS and TH) and Na(+), Mg(2+), Ca(2+), Cl(-) and [Formula: see text]. The results display that rock-weathering interactions and ion-exchange processes play important role in controlling groundwater chemistry. Saturation index values also indicate that water chemistry is significantly affected by carbonate minerals such as calcite, aragonite and dolomite. US Salinity Laboratory(USSL) and Wilcox diagrams together with permeability index values reveal that most of the groundwater samples are suitable for irrigation purpose. However, in some regions, the water samples do not indicate required irrigational quality.

The effect of chemical and organic amendments on sodium exchange equilibria in a calcareous sodic soil.

In this study, the reclamation of a calcareous sodic soil with the exchangeable sodium percentage (ESP) value of 26.6% was investigated using the cheap and readily available chemical and organic materials including natural bentonite and zeolite saturated with calcium (Ca2+), waste calcite, three metal oxide nanoparticles functionalized with an acidic extract of potato residues, and potato residues. Chemical amendments were added to the soil at a rate of 2%, while potato residues were applied at the rates of 2 and 4% by weight. The ESP in the amended soils was reduced in the range of 0.9-4.9% compared to the control soil, and the smallest and the largest decline was respectively observed in treatments containing waste calcite and 4% of potato residues. Despite the reduction in ESP, the values of this parameter were not below 15% at the end of a 40-day incubation period. So, the effect of solutions of varying sodium adsorption ratio (SAR) values of 0, 5, 10, 20, 30, 40, and 50 on sodium (Na+) exchange equilibria was evaluated in batch systems. The empirical models (simple linear, Temkin, and Dubinin-Radushkevich) fitted well to experimental data. The relations of quantity to intensity (Q/I) revealed that the potential buffering capacity for Na+ (PBCNa) varied from 0.275 to 0.337 ((cmolc kg(-1)) (mmol L(-1))(-1/2)) in the control soil and amended soils. The relationship between exchangeable sodium ratio (ESR) and SAR was individually determined for the control soil and amended soils. The values of Gapon selectivity coefficient (KG) of Na+ differed from the value suggested by U.S. Salinity Laboratory (USSL). The PHREEQC, a geochemical computer program, was applied to simulate Na+ exchange isotherms by using the mechanistic cation exchange model (CEM) along with Gaines-Thomas selectivity coefficients. The simulation results indicated that Na+ exchange isotherms and Q/I and ESR-SAR relations were influenced by the type of counter anions. The values of K G increased in the presence of bicarbonate, sulfate, and phosphate in comparison with the presence of chloride, and the largest value was obtained in the presence of phosphate. So, it can be concluded that the presence of chloride anion is more favorable to reduce ESP compared to other anions, while the presence of phosphate anion makes the reclamation process more difficult. Furthermore, it is possible to reclaim sodic soils using inexpensive and readily available compounds such as potato residues and water management.

Evaluating the suitability of groundwater for irrigational purposes in some selected districts of the Upper West region of Ghana

Groundwater is a very important asset to the people of the Upper West region of the Ghana where majority of them are farmers. Groundwater serves as the most reliable source of water for their domestic and agricultural activities. This study was aimed at assessing the suitability of groundwater for irrigational purposes in some selected communities of five districts where farming activities are very intensive. Twenty-three groundwater samples were collected and analysed for major anions and cations. Physicochemical parameters such as electrical conductivity (EC) and total dissolved solids (TDS) were also measured. From the results of the analyses and measurements, the suitability of the groundwater for irrigation were evaluated based on the TDS, EC, percentage sodium (%Na), sodium adsorption ratio (SAR), permeability index (PI), residual sodium carbonate (RSC), magnesium adsorption ratio (MAR), Kelly’s ratio (KR) and chloro-alkaline Indices (CAI). US salinity laboratory diagram and Wilcox diagrams were also applied. The EC results show that the groundwater in the study area can be classified as none and slight to moderate. According to the US salinity diagram, groundwater in the study area falls within the low salinity-low sodium hazard and medium salinity-low sodium hazard class. The %Na and the resulting Wilcox diagram also classify the groundwater as excellent to good and good to permissible. The groundwater in the study area is generally good for irrigation purposes. However, there are few instances which are problematic and would require special irrigation methods.

Evaluation of groundwater quality and assessment of scaling potential and corrosiveness of water samples in Kadkan aquifer, Khorasan-e-Razavi Province, Iran.

The chemical analysis of 129 groundwater samples in the Kadkan area, Khorasan-e-Razavi Province, NE of Iran was evaluated to determine the hydrochemical processes, assessment of groundwater quality for irrigation purposes, corrosiveness, and scaling potential of the groundwater. Accordingly, the suitability of groundwater for irrigation was evaluated based on the sodium adsorption ratio, residual sodium carbonate, sodium percent, salinity hazard, and US Salinity Laboratory hazard diagram. Based on the electrical conductivity and sodium adsorption ratio, the dominant classes are C3-S1, C3-S2, C2-S1, and C4-S2. According to the Wilcox plot, about 50 % of the samples fall in the "Excellent to Good" and "Good to Permissible" classes. Besides, the Langelier saturation index, Ryznar stability index (RSI), Larson-Skold index, and Puckorius scaling index were evaluated for assessing the corrosiveness and scaling potential of the groundwater. Corrosiveness and scaling indices stated that the majority of samples are classified into "Aggressive" and "Very Aggressive" category. In addition, chloride and sulfate interfere in 90 % of the samples. Assessment of hydrochemical characteristics indicates Na-Mg-Cl as the predominant hydrochemical type. Spatial distribution of hydrochemical parameters indicates that hydrochemical processes are influenced by geology and hydrogeology of Kadkan aquifer. The Gibbs plots gave an indication that groundwater chemistry in this area may have acquired the chemistry mainly from evaporation and mineral precipitation. Grouping the samples based on Q-mode hierarchical cluster analysis helped to more separation of similar samples. The R-mode HCA grouped analyzed parameters into two groups based on similarity of hydrochemical characteristics. As a result, the samples collected in northern and southern parts of the study area show the best quality (i.e., lowest salinity) for some purposes such as irrigation and drinking.

Evaluation of Groundwater Quality and Its Suitability for Domestic and Irrigation Use in Parts of the Chandauli-Varanasi Region, Uttar Pradesh, India

The present study focused on the hydrochemistry of groundwater in parts of Chandauli-Varanasi region to assess the quality of groundwater for determining its suitability for drinking and agricultural purposes. Urbanization and agriculture activities have a lot of impacts on the groundwater quality of the study area. A total of 70 ground water samples were collected randomly from different sources viz. hand pump, dug wells and bore wells, and analyzed for major cations and anions. The domination of cations and anions was in the order of Na > Ca > Mg > K and HCO3 > Cl > SO4 > NO3 > F. The Piper classification for hydrogeochemical facies indicates that alkaline earth exceeds alkalis and weak acids exceed strong acid. Water quality index rating was calculated to quantify overall water quality for human consumption. Out of 70 groundwater samples, 7% and 10% samples exhibit water unsuitable for drinking purposes in pre- and post-monsoon, respectively, due to effective leaching of ions, direct discharge of domestic effluents and agricultural activities. Residual sodium carbonate values revealed that 6% sample is not suitable for irrigation purposes in both the seasons due to low permeability of the soil. The calculated values of PI indicate that the water for irrigation uses is excellent to good quality in both seasons. As per Wilcox’s diagram and US salinity laboratory classification, most of the groundwater samples are suitable for irrigation except one sample which is unsuitable for irrigation purposes. The overall quality of groundwater in post-monsoon season in all chemical constituents is on the higher side due to dissolution of surface pollutants during the infiltration and percolation of rainwater at few places due to agricultural and domestic activities.

Groundwater Studies with Special Emphasis on Seasonal Variation of Groundwater Quality in a Coastal Aquifer

The qualitative and quantitative assessment of groundwater is obligatory pre-requisite for developing countries like India with rural based economy. It is essential to evolve a strategy for ecologically sustainable development of groundwater resources which can be done only through exploration of hydro-geological environment. In the present study, groundwater studies, with special emphasis on groundwater quality and its variation with season have been carried out for upland areas of Nellore district, situated on the East Coast of India. Groundwater quality data of samples collected during pre and post monsoon season in the year 2011 by State Groundwater Department, Nellore have been used for finding its suitability for drinking and agricultural purposes. The data pertaining to the following parameters / ions, viz., Hydrogen Concentration(pH), Total Dissolved Solids(TDS), Total Hardness(TH), Calcium(Ca2+), Magnesium(Mg2+), Chlorides(Cl), Sodium(Na+), Potassium(K+), and Sulphates(SO42+) has been analyzed. It has been observed that in post-monsoon period most of the water samples are found not suitable for drinking. For evaluation of water quality for irrigation, US Salinity Laboratory’s and Wilcox’s diagrams, and percent Sodium (Na+) are used. It is found that the majority of the groundwater samples are not good for irrigation in post-monsoon compared to that in pre-monsoon.

Evaluation of groundwater suitability for irrigation in the Skhirat region, Northwest of Morocco.

Morocco has arid and semiarid climates. Irrigation is an imperative for agriculture. Skhirat region is known for the production of vegetables. Intensive peri-urban agriculture is associated with inconsiderate pumping of groundwater, and water becomes less abundant and of poor quality resulting in degradation of soil and water quality. Therefore, the objective of this research work was the assessment of the quality of irrigation water. The study site is located in a coastal area and dedicated to intensive land use for growing vegetables in a peri-urban agricultural zone. Monitoring of physicochemical parameters of water was carried out in 77 wells. Parameters like pH, electrical conductivity, and piezometric level were measured in situ while others like total dissolved solids and ionic balance were measured in laboratory whereas other parameters were calculated from those measured. Results showed that Na and Ca are predominant cations while Cl and SO4 are predominant anions. Piper diagram reveals two facies: sodic and calcic chlorinated. Regarding the permeability index, all wells are suitable for irrigation. The US Salinity Laboratory (USSL) diagram reveals that irrigation water has high salinization risk and low to medium alkalinization risk. The groundwater in the region is classified as very hard category; however, it does not present any risk of sodicity. These waters have a high risk of toxicity to chloride ions. In summary, although the groundwater in the Skhirat region presents a high risk of salinization, it is of good quality suitable for irrigation. Agricultural practices should be well managed to secure safe use of the water resource for a sustainable development of the agriculture in the region.

Major ion chemistry of the ground water at the Khoda Village, Ghaziabad, India

The ground water quality in and around the Khoda village, Ghaziabad, India, has been evaluated for sustainability and its suitability for drinking, domestic and irrigation purposes. A total of 184 ground water samples were collected from India Mark II hand-pumps during pre-monsoon (March 2011) and post-monsoon (October 2010) periods, respectively. All the samples were analyzed for 29 physicochemical water quality parameters. According to the Soltan’s classification, the majority of the samples were normal sulfate, normal bicarbonate and normal chloride types, respectively, during pre- and post-monsoon seasons. Base-exchange, meteoric genesis, Langelier saturation and Ryznar stability indices were also estimated. The total ionic dominance (meq/L) pattern follows the order Na+ > HCO3− > Cl− > Mg2+ > SO42− > Ca2+. Piper trilinear and Chadha’s rectangular diagrams indicated that alkali metals (Na+ + K+) exceed alkaline earth metals (Ca2+ + Mg2+) and anions of strong acids (SO42− + Cl−) dominate over anions of weak acids (HCO3− + CO3−), suggesting that this water is of the Na+ − Cl− and Na2SO4 types. Ground water suitability for irrigation was assessed using electrical conductivity and percent sodium, the US Salinity Laboratory’s diagram, residual sodium carbonate (RSC), salinity index, chlorinity index, sodicity index, Kelly’s Index and magnesium hazard.

Groundwater Quality Assessment in a Coastal Sand Aquifer: Implications for Drinking Water and Agricultural Use

In many countries, specifically those located in semi-arid zones, groundwater is the major source of drinking water, domestic and agriculture use. The present hydro geochemical study was carried out in the coastal sand aquifer of Thiaroye Dakar, Senegal. A total of 36 groundwater samples were collected from different dug wells, piezometers and boreholes in the study area to decipher hydro geochemistry and groundwater quality for determining its suitability for drinking and agricultural purposes. The analytical results of hydro geochemical parameters such as Na + , Ca 2+ , Mg 2+ , Cl - , SO4 2- of groundwater samples in the study area reveals that over 66% were found to be well within the safe range with respect to the world Health Organization for drinking water indicating that most of groundwater sampling sites are fit for drinking with respect of these parameters. The K + concentrations show that 56% of groundwater is suitable for drinking water. On the other hand, NO 3 - concentration show high levels exceeding the maximum permissible limits for drinking standard at almost 61% of groundwater samples indicating groundwater which is unfit for drinking water thus suggesting the need for treatment or precautionary measures to use for drinking water purpose. The TDS and EC values of groundwater indicate respectively that 69.5 and 61% are suitable for drinking water. According to the irrigation quality parameters such %N, SAR, RSC, KR and Ca 2+ /Mg 2+ ratio it was demonstrated that over 80% of groundwater samples in the study area are suitable for irrigation purpose. Furthermore, the interpretation of graphical plots such as Wilcox and US Salinity Laboratory for the classification of groundwater shows that most of the groundwater samples in the study area are suitable for irrigation purpose except for few groundwater samples.

The water quality index and hydrochemical characterization of groundwater resources in Hafar Albatin, Saudi Arabia

The main objectives of this study were to: evaluate and compare the treated and untreated groundwater quality in Hafar Albatin, Saudi Arabia for drinking purpose using water quality index (WQI), study the suitability of untreated groundwater for irrigation purpose, and investigate hydrochemical processes that control the groundwater chemistry. The WQI calculations required several physiochemical water parameters including EC, pH, Ca2+, Mg2+, Na+, K+, Cl−, SO4 2−, and NO3 −. The results showed that more than 47 % of the untreated wells considered unsuitable (class V), 39 % considered very poor water (class IV), and 14 % considered poor water (class III) for drinking purposes. The treatment of groundwater improved its quality to poor (class III) and even good (class II). Approximately 64 % of all treated waters were of good quality; however, the rest remained poor. Most studied untreated groundwaters were considered unsuitable for irrigation due to salinity hazards; however, no sodicity hazards were anticipated. US salinity laboratory diagram revealed that the groundwater samples were grouped into five categories; 53.6 % of water samples were distributed in category C4–S2 highlighting very high salinity hazards and medium sodium hazards class. Durov and Piper diagrams revealed that the majority of investigated waters were sodium chloride and calcium sulfate–chloride water type. The Gibbs’s diagram revealed that the chemical weathering of rock-forming minerals and evaporation are influencing the groundwater quality. The hydrochemical modeling indicated that all water samples were undersaturated for halite and 89 % of water samples were saturated for anhydrite and gypsum.

Hydrogeochemical characterization and quality assessment of groundwater around Umrer coal mine area Nagpur District, Maharashtra, India

Quality assessment as well as hydrogeochemical characterization of 45 representative groundwater samples around Umrer coal mine area was undertaken. The pH of the water lies in the normal range i.e. from 7.5 to 8.5, the electrical conductivity varies from 826 to 1,741, the total hardness varies from 289 to 1,302 and the TDS values range from 528.6 to 1,114.2 mg/l which reflects variation in lithology and thus, the distinction in hydrogeological regime. The cation chemistry is dominated by Ca2+ and Mg2+ while anion chemistry is dominated by Cl− and HCO3−. Out of total ten hydrochemical facies, the two dominant facies are Mg–Ca–HCO3 (37.7 %) and Ca–Mg–SO4–HCO3 (17.7 %). The groundwater in the study area, in general, is useful for drinking and domestic use; however, it has marginal utility for irrigation purpose. Standard US Salinity Laboratory classification shows that water of the study area belongs to C2–S1 and C3–S1 classes. The concentration of 9 trace elements analysed from 18 samples did not exceed the desirable limit.

Groundwater Quality in Parts of Central Ganga Basin, Aligarh City, Uttar Pradesh, India

Hydrochemistry of groundwater in Aligarh city of Uttar Pradesh, India was used to determine its suitability for drinking and irrigation purpose. Physical and chemical parameters of groundwater such as electrical conductivity, pH, total dissolved solids (TDS), Na+, K+, Ca2+, Mg2+, Cl–, HCO3 –, CO3 2– and SO4 2–, were determined in one hundred groundwater samples collected from open wells as well as hand pumps in 2010. Ionic concentrations of the groundwater vary spatially and temporarily and the water is alkaline in nature. The higher values of some parameters at certain locations indicate contamination of the groundwater, making it unsuitable for specific applications. Twenty five percent of the wells lie under the medium salinity zone (EC 750-2250 micro mhos/cm). The Sodium Absorption Ratio (SAR) values range between 0.26 to 15.5 indicating that some water samples fall under the category of medium salinity hazard and are not suitable for irrigation. The groundwater of the area has also been classified on the basis of the Piper diagram. Many of the samples fall in the magnesium and sodium or potassium type, and 50% samples fall in no dominant type. As per US Salinity Laboratory Classification for irrigation water, most of the water samples fall under C2-S1 class (medium salinity and low SAR), eighteen locations fall under the category C3-S2 class (medium salinity and low SAR) and one location Luxmi Nagar shows C3-S3 (high salinity and high SAR). The major reason for the decline in water quality is the dumping of large amount of acid wastes by illegal lock factories, and another important source of pollution is slaughterhouse where at least 2500 buffaloes are slaughtered daily.

盐胁迫对2种栎树苗期生长和根系生长发育的影响

以低浓度（50 mmol/L）和高浓度（150 mmol/L）NaCl处理弗吉尼亚栎（<em>Quercus virginiana</em>）和麻栎（<em>Quercus acutissima</em>）1年生幼苗，研究了2种栎树在盐胁迫下的生长、对盐分的敏感性和耐受性及其根系形态学参数变化以及根系对盐离子的吸收与积累。结果表明，高浓度盐胁迫明显抑制了2种栎树地上部生物量的积累（<em>P</em> < 0.05），而低浓度盐胁迫对弗吉尼亚栎地上部干重的影响不明显，但显著抑制了麻栎地上部干重（<em>P</em> < 0.05）；2种栎树的根冠比在盐胁迫下呈增加趋势，特别是在高浓度盐胁迫下，2种栎树的根冠比明显增加（<em>P</em> < 0.05），盐胁迫下增加生物量在根部的分配是植物应对盐胁迫的方式之一。2种栎树根部生物量积累在盐胁迫下变化不明显，但2种栎树根系形态学参数在盐胁迫下的响应不同，弗吉尼亚栎根系总长度、总表面积和总体积在盐胁迫下均有不同程度增加，特别是在低浓度盐胁迫下，根系形态学参数明显增加（<em>P</em> < 0.05），但麻栎根系形态学参数有下降趋势，但与对照相比变化不明显；通过对不同径级根系总长的分析发现，弗吉尼亚栎根系总长度的增加主要是由于直径小于2 mm的细根总长的增加，细根长度的增加对于植物吸收水分和营养物质具有重要意义；通过对Na⁺和Cl^-在根系的含量分析表明，盐胁迫下2种栎树根系盐离子的积累均有明显增加，但弗吉尼亚栎根系盐离子的含量在低浓度和高浓度盐胁迫下的差异不明显，而麻栎在高浓度盐胁迫下根系盐离子的含量明显高于弗吉尼亚栎。综合2种栎树盐胁迫下的生物量分配策略和根系形态学响应以及盐离子的积累规律，证明2种栎树尽管在生物量分配策略方面具有相同的特点，但根系的响应策略截然不同，弗吉尼亚栎在盐胁迫下能够扩大根系吸收范围，维持较高的K⁺/Na⁺比值，而麻栎在盐胁迫下根系由于吸收过多的盐离子，导致根系的生长发育受到抑制，影响了根系在逆境中的分布范围，从而在一定程度上避免了进一步的盐害。;It is well known that saline soil, which takes up about 25% of the whole land area, is one of the most widely distributed soils on Earth. In China, the saline area is over 34 million hm², including one million hm² coastal saline soil. Soil salinity refrains the development and growth of most plant species, except for few species like halophytes. To understand the mechanism of salt tolerance, many studies have been carried out on the herbaceous halophytes, the tolerant woody plants and the sensitive and tolerant crop plants, but much less is known concerning the salt susceptibility and tolerance of oak trees.<em> Quercus</em> <em>virginiana</em> and <em>Quercus acutissima </em>are two different origin oak trees. <em>Q. virginiana</em>, is considered as a moderately sensitive tree species to soil salinity according to US Salinity Laboratory classification. It is one of the dominant tree species along southeastern coast of the United States and has the extreme tolerance to high concentration of salt fog. <em>Q. virginiana</em> acorn was introduced to China in 2000 for the first time, and its tolerance to salts has been confirmed through the regional trial along the coastline of southeastern China.<em> Q. acutissima</em> is widely distributed in China and few researches are reported about its response on salt stress.<br>The response of plants to excess salt is complex and involves some changes in morphology, physiology and metabolism. Among these changes, the variations changes in the biomass allocation and root morphological characteristics of plants are two important adaptive mechanisms under salt stress. In this research, the changes of root morphology and biomass accumulation of 1-year-old seedlings of <em>Q. virginiana</em> and <em>Q. acutissima </em>were investigated under higher concentration (150 mmol/L) and lower concentration (50 mmol/L) of sodium chloride solution treatments. The results showed that the growth of shoots of two oak trees were significantly inhibited under higher concentration of salt stress, while no obvious changes were observed for the growth of shoots of <em>Q. virginiana </em>under lower concentrations of NaCl. The ratio of root to shoot for two oak trees increased under both concentration of NaCl, which was considered as a biomass allocation strategy for a certain class of plants under salt stress.<br>For the two oak trees, salinity did not induce the significant change on the root biomass accumulation. While the root morphological responses under salt stress were different between two oak trees. For <em>Q. virginiana</em>, the total root length, root surface area and root volume were increased in various degrees under both lower and higher concentration of NaCl, and significant increasement was observed under lower concentration of NaCl, especially for the stimulation of fine roots with the diameter less than 2mm. The fine roots are more effective than the thicker roots in nutrient and water absorption. For <em>Q. acutissima</em>, although its root development and expandation were inhibited under salt stress, no significant difference was observed when compared to that of control. It was also observed that the different patterns of accumulation of Na⁺ and Cl^- in roots for two oak trees. Therefore, according to the biomass allocation strategy and root morphological responses and ions accumulation patterns of two oak trees under salt stress, it may be deduced that the both oak trees have the similar biomass allocation strategy when exposed to salinity, but have totally different responses on the root development and salt ions accumulation. <em>Q. virginiana</em> could expand the root scope for more effective nutrient absorption to relieve the toxicity of redundant salt ions, while <em>Q. acutissima</em> restricted the expanding of roots in salinity environment due to the redundant uptake of salt ions, and thus lessens the further damage to roots.

Water quality assessment of carbonate aquifers in southern Latium region, Central Italy: a case study for irrigation and drinking purposes

In southern Latium region, Central Italy, groundwater and spring water resources in the carbonate aquifers are the major contributors of drinking and irrigation water supply. The aim of this study was to review hydrochemical processes that control the groundwater chemistry and to determine the suitability of springs and groundwater for irrigation and drinking purposes on the basis of the water quality indices. Physical (pH, electrical conductivity, total dissolved solids) and hydrochemical characteristics (Na+, K+, Ca2+, Mg2+, HCO3−, Cl−, and SO4−) of springs and groundwater were determined. To assess the water quality, chemical parameters like sodium adsorption ratio (SAR), total hardness, Mg-hazard (MH), sodium percentage (Na %), salinity hazard, permeability index, and Kelly’s ratio were calculated based on the analytical results. A Durov diagram plot revealed that the groundwater has been evolved from Ca to HCO3 recharge water, followed by mixing and reverse ion exchange processes, due to the respective dominance of Na–Cl and Ca–Cl water types. According to Gibbs’s diagram plots, chemical weathering of rock forming minerals is the major driving force controlling water chemistry in this area. Groundwater and spring samples were grouped into six categories according to irrigation water quality assessment diagram of US Salinity Laboratory classification and most of the water samples distributed in category C2–S1 and C3–S1 highlighting medium to high salinity hazard and low sodium content class. The results of hydrochemical analyses and the calculated water quality parameters suggest that most of the water samples are suitable for irrigation and drinking purposes, except for the samples influenced by seawater and enhanced water–rock interaction. High values of salinity, Na %, SAR, and MH at certain sites, restrict the suitability for agricultural uses.

Impact of recharge from a check dam on groundwater quality and assessment of suitability for drinking and irrigation purposes

Assessment of surface water and groundwater quality is necessary as it controls their usability for drinking and irrigation purposes. This study was carried out to assess the suitability of groundwater for these purposes and to understand the impact of water stored in a check dam on groundwater quality near Chennai, Tamil Nadu, India. Water samples were collected from a check dam across Arani River and 13 nearby wells during October 2010, January 2011, and April 2011. These samples were analyzed for pH, electrical conductivity (EC), and calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, and sulfate concentrations. The World Health Organization and the Bureau of Indian Standards guidelines were used to assess the suitability of groundwater for the purpose of drinking. Suitability of water for irrigation was determined based on the EC, sodium adsorption ratio, US Salinity Laboratory diagram, percentage sodium, Wilcox’s diagram, Kelly’s index, and Doneen’s permeability index. About 38 % of the groundwater samples were suitable for drinking and 70 % were suitable for irrigational use. Water stored in the check dam and groundwater in the wells closer to the structure were suitable for both drinking and irrigation purposes. The study confirms that the check dam in this area improves the groundwater quality in its surroundings.

Evaluation of groundwater quality in Madurai City, South India for drinking, irrigation and construction purposes

The present research is contributed on groundwater quality, its deterioration and evaluation based on drinking, irrigation, and construction standards. The study area chosen for investigation on water quality is the Tirunagar (TN) area, located in the south-west of Madurai City. The TN area was formerly an agricultural land but presently a residential area that is at a starvation of drinking water quality. A total of 49 bore well samples from TN and Amaithisolai (AS) were investigated for drinking, irrigation, and construction qualities based on various physicochemical parameters. The chemistry of groundwater samples was reflected from very hard and noncarbonate-dominating species. TN was recorded with higher inorganic species in groundwater sources than AS. The Water Quality Index values indicated that 75 % of the samples fall under excellent category and the positive Langelier Saturation Index values of the samples highlighted their tendency to deposit calcium carbonate. The Gibbs plot showed that AS samples were categorized under the domination of rock–water interaction whereas the TN samples under evaporation zone. The US Salinity Laboratory Staff plot depicted that all the groundwater sources at AS with C3S1 type whereas 88 % of the TN sources represented C4S1 type. The results from Wilcox diagram for irrigation inferred that the groundwater sources at AS were permissible, but 68 % of the samples at TN was registered under unfit type. The suitability of groundwater from the knowledge of residual sodium carbonate, sodium absorption ratio, and sodium percentage was also investigated. The perception based on standards recommended the groundwater sources for construction activities. The contribution of ionic species and inter-relationship among the ions were also interpreted from the knowledge of statistical studies.

Hydrochemical characteristics and GIS-based assessment of groundwater quality in the coastal aquifers of Tuticorin corporation, Tamilnadu, India

Tuticorin corporation stretches geographically from 8°43′–8°51′N latitude and 78°5′–78°10′E longitude, positioned in the East–West International sea routes on the South–East coast of India. The rapid urban developments in the past two decades of Tuticorin have caused depletion of groundwater quantity, and deterioration of quality through excessive consumption and influx of pollutants from natural and anthropogenic activities. The water samples collected in the field were analyzed for electrical conductivity, pH, total dissolved solids, major cations like calcium, magnesium, sodium, potassium, and anions SUCH AS bicarbonate, carbonate, chloride, nitrate and sulfate, in the laboratory using the standard methods given by the American Public Health Association. In order to assess the groundwater quality, 36 groundwater samples had been collected in year 2011. The geographic information system-based spatial distribution map of different major elements has been prepared using ArcGIS 9.2. The Piper plot shows that most of the groundwater samples fall in the field of Ca2+-Mg2+–Cl−-SO42− and Na+-K+–Cl−-HCO3− by projecting the position on the plots in the triangular field. The cation concentration indicate that 83, 39 and 22 % of the K+, Na+, Ca2+ concentrations exceed the WHO limit. As per Wilcox’s diagram and US Salinity laboratory classification, most of the groundwater samples are not suitable for irrigation due to the presence of high salinity and medium sodium hazard. Irrigation waters classified based on sodium absorption ratio, have revealed that 52 % groundwater are in general safe for irrigation, which needs treatment before use. permeability index also indicates that the groundwater samples are suitable for irrigation purpose.