Hydrogeochemistry Research Papers - Academia.edu (original) (raw)

End-member mixing models have been widely used to separate the different components of a hydrograph, but their effectiveness suffers from uncertainty in both the
identiﬁcation of end-members and spatiotemporal variation in end-member concentrations. In this paper, we outline a procedure, based on the generalized likelihood uncertainty
estimation (GLUE) framework, to more inclusively evaluate uncertainty in mixing models than existing approaches. We apply this procedure, referred to as G-EMMA, to a yearlong
chemical data set from the heavily impacted agricultural Lissertocht catchment, Netherlands, and compare its results to the ‘‘traditional’’ end-member mixing analysis
(EMMA). While the traditional approach appears unable to adequately deal with the large spatial variation in one of the end-members, the G-EMMA procedure successfully
identiﬁed, with varying uncertainty, contributions of ﬁve different end-members to the stream. Our results suggest that the concentration distribution of ‘‘effective’’ end-members, that is, the ﬂux-weighted input of an end-member to the stream, can differ markedly from
that inferred from sampling of water stored in the catchment. Results also show that the uncertainty arising from identifying the correct end-members may alter calculated end-member contributions by up to 30%, stressing the importance of including the identiﬁcation
of end-members in the uncertainty assessment.

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- Hydrogeology, Hydrology, Hydrogeochemistry, Generalized Likelihood Uncertainty Estimation
- by Elango L
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- Hydrogeology, Environmetal Earth Science, Groundwater Contamination, Water Pollution

Emerging organic compounds EOC are substances which have been only recently determined as pollutants, and substances which have been newly developed or discovered in the environment. EOC in groundwater can cause adverse effects on the environment and human health. They enter into the natural environment as a result of various anthropogenic activities. The article provides an overview of emerging organic pollutants that occur in groundwater. These compounds are drug residues, substances originating from personal care products, pesticides, veterinary products, food additives, nanomaterials, industrial and other compounds found in wastewater. The article describes the main sources and the presence of EOC in groundwater, pathways and potential impacts (risks). An overview of EOC detection research in the world is presented. Within the review of Slovenian studies the investigations dealing with the determination of wide spectrum of EOC presence in groundwater, with drug residues in groundwater and waste water, or with the development of analytical methods for these substances were analyzed. From the entire analysis we inferred that we must be aware of the possible presence of EOC risk in groundwater even in small concentrations. To reduce the yet to some extent unknown risks, it is necessary to determine EOC threshold values in groundwater and their impact. In the future it will be necessary to identify new pollutants, to develop new analytical methods to determine their sources and routes, and in particular, to establish monitoring for these substances.

The pace of urbanisation in Ranchi is increasing since the Jharkhand state has been formed, hence a study was carried to find the status of groundwater quality in peri-urban agglomeration of Ranchi city. Samples were collected from 44 sites in monsoon season from rural, periurban, urban, industrial and commercial zones of the city. Along with the physico-chemical parameters they were also analysed for 10 heavy metals namely As, Mn, Ni, Se, Fe, Cu, Cd, Co, Cr and Pb in which except As, Mn, Ni and Se rest of the elements were below detection level. The concentrations (ppb) of highly toxic metals viz., As, Ni, Mn and Se ranged from 0.0-200, 0.0-80, 0.0-4200 and 30-140 respectively which are above the acceptable limits as per BIS/WHO standards for drinking purpose. ANOVA showed that pH, TDS, EC, Total alkalinity, Total hardness, Cl-, SO42-, F-, Na2+ and Se showed significant variation at 0.05 significance level. Hydrochemistry was dominated by calcium, bicarbonate and sodium bicarbonate in the study area. These facts are also supported by PCA and correlation. The order of relative abundance of the anions was Cl-> SO42->NO3->F->PO43-and for cations was Ca2+~Na+>Mg2+>K+. Zonal variation revealed that as compared to rural, peri-urban and urban zones, industrial and commercial zones had degraded water quality. As depicted from Water Quality Index (WQI) 80% of sampling locations have poor water quality, 7% very poor water quality, 4% unfit for drinking and only 9% out of the 44 sampling locations have good water quality. Health risk assessment signifies the probability of the noncarcinogenic effect due to the presence of arsenic and selenium as compared to carcinogenic effect is more for the residents of the study area.

- by Paulami Sahu
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- Environmental Science, Groundwater, Groundwater Hydrology, Hydrogeochemistry

In the light of progressive depletion of groundwater reservoir and water quality deterioration of the Neyveli basin, an investigation on dissolved major constituents in 25 groundwater samples was performed. The main objective was detection of processes for the geochemical assessment throughout the area. Neyveli aquifer is intensively inhabited during the last decenniums, leading to expansion of the residential and agricultural area. Besides semi-aridity, rapid social and economic development stimulates greater demand for water, which is gradually fulfilled by groundwater extraction. Groundwaters of the study area are characterized by the dominance of Na + K over Ca + Mg. HCO3 was found to be the dominant anion followed by Cl and SO4. High positive correlation was obtained among the following ions: Ca–Mg, Cl–Ca,Mg, Na–K, HCO3–H4SiO4, and F–K. The hydrochemical types in the area can be divided into two major groups: the first group includes mixed Ca–Mg–Cl and Ca–Cl types. The second group comprises mixed Ca–Na–HCO3 and Ca–HCO3 types. Most of the groundwater samples are within the permissible limit of WHO standard. Interpretation of data suggests that weathering, ion exchange reactions, and evaporation to some extent are the dominant factors that determine the major ionic composition in the study area. في ضوء نضوب التدريجي لخزان المياه الجوفية وتدهور نوعية المياه في حوض Neyveli ، تحقيقا بشأن حل المكونات الرئيسية في عينات المياه الجوفية 25 قد أنجز. وكان الهدف الرئيسي من عمليات الكشف عن تقييم الجيوكيميائية في جميع أنحاء المنطقة. ويسكنها بشكل مكثف Neyveli طبقة المياه الجوفية خلال decenniums الماضي ، مما أدى إلى التوسع في المنطقة السكنية والزراعية. وبالاضافة الى الجفاف نصف النهائي ، سريع التنمية الاجتماعية والاقتصادية ويحفز زيادة الطلب على المياه ، التي تؤدى تدريجيا عن طريق استخراج المياه الجوفية. وتتميز المياه الجوفية في منطقة الدراسة عن طريق هيمنة نا + ك + الكالسيوم على المغنيسيوم. تم العثور على HCO3 أن تكون مهيمنة أنيون يليه الكلورين وSO4. تم الحصول على العلاقة الإيجابية بين السامية الأيونات التالية : الكالسيوم ، الماغنسيوم ، الكالسيوم ، الكلور ، الماغنسيوم ، الصوديوم ، البوتاسيوم ، HCO3 - H4SiO4 وكيه. ويمكن تقسيم أنواع الهيدروكيميائية في المنطقة إلى مجموعتين رئيسيتين : المجموعة الأولى تضم مختلطة الكالسيوم ، الماغنسيوم ، الكالسيوم وأنواع الكلور ، كلور. المجموعة الثانية تضم أنواع مختلطة الكالسيوم ، الصوديوم والكالسيوم ، HCO3 HCO3. معظم العينات الجوفية تقع ضمن الحد المسموح به من منظمة الصحة العالمية القياسية. تفسير البيانات تشير إلى أن العوامل الجوية التبادل الأيوني ، وردود الفعل والتبخر الى حد ما هي العوامل المسيطرة التي تحدد تركيبة الأيونية الرئيسية في منطقة الدراسة.

- by Sabarathinam Chidambaram
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- Civil Engineering, Geology, Hydrogeology, Environmental Geology

Reclaimed water from small wastewater treatment facilities in the rural areas of the Beira Interior region (Portugal) may constitute an alternative water source for aquifer recharge. A 21-month monitoring period in a constructed wetland treatment system has shown that 21,500 m3 year−1 of treated wastewater
(reclaimed water) could be used for aquifer recharge. A GIS-based multi-criteria analysis was performed, combining ten thematic maps and economic, environmental and technical criteria, in order to produce a suitability map for the location of sites for reclaimed water infiltration. The areas chosen for aquifer
recharge with infiltration basins are mainly composed of anthrosol with more than 1 m deep and fine sand texture, which allows an average infiltration velocity of up to 1 m d−1. These characteristics will provide a final polishing treatment of the reclaimed water after infiltration (soil aquifer treatment (SAT)),
suitable for the removal of the residual load (trace organics, nutrients, heavy metals and pathogens).
The risk of groundwater contamination is low since the water table in the anthrosol areas ranges from 10 m to 50 m. On the other hand, these depths allow a guaranteed unsaturated area suitable for SAT. An area of 13,944 ha was selected for study, but only 1607 ha are suitable for reclaimed water infiltration.
Approximately 1280 m2 were considered enough to set up 4 infiltration basins to work in flooding and
drying cycles.

Prospecting studies indicate that Rwanda has a potential capacity to generate geothermal energy in the volcano-tectonically active zones of the East African Rift System (EARS). Two typical regions, Gisenyi and Mashyuza, were reevaluated
for the geothermal potential in Rwanda, where the hot springs were of Na-HCO3 type waters. Geothermometers were applied to estimate subsurface temperatures of Gisenyi and Mashyuza springs and their suitability were discussed using Na-K-Mg diagram. In contradiction to previous studies, the results showed that only K-Mg geothermometer provided reliable estimations for Gisenyi and Mashyuza prospects for which reservoir temperatures are too low for energy production.

- by Evalde Mulindankaka and +2
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- Hydrogeochemistry, Geothermal Water, Geothermometers

The Sierra Madre Oriental (SMO) is composed of ranges with important regional geological structures in highly fractured carbonate rocks (Abra Formation), which facilitate the recharge of aquifers. At the regional scale, recharge occurs in the western SMO and locally, in ranges such as Palmillas, La Colmena and Abra, while the regional discharge is to the east in the Huasteca zone. Intermountain valleys, such as El Salto, are located near the regional discharge zone. Three end members were identified in these regions, one related to local flow, another to intermediate and a third to regional flow. These flows define ternary mixing processes in groundwater. In this paper, the evolution of groundwater is studied, which is important for learning the system performance and hydrogeochemical processes through VISHMOD (Virtual Samples in Hydrochemical Modeling) methodology. The mixing model for the intermountain valleys indicates that many recharges occur, for which local flow contributes 68.3%, intermediate flow 12.3% and regional flow 19.4%. The inverse modeling shows that the water-rock interaction, precipitation and/or dissolution of calcite, gypsum and dolomite are the main processes occurring in the aquifer system of the intermountain valleys.

- by Jose Ramos and +3
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- Hydrogeology, Central America and Mexico, Groundwater, Groundwater Contamination

The present study seeks to evaluate the hydrogeochemistry of Tabriz plain in NW Iran, through major ion chemistry and their spatial variations. In order to accomplish these, groundwater sampling from 30 shallow and deep wells in the plain were carried out in July 2012. The water samples were analyzed for various physicochemical parameters such as pH, EC, Na⁺, Ca²⁺, K⁺, Mg²⁺, Cl⁻, CO3²⁻, HCO3⁻, SO4²⁻ and NO3⁻. Chadha’s diagram demonstrates that most of the groundwaters belonged to the Na–Cl and mixed Ca–Mg–Cl hydrochemical facies. The concentrations of some major ions in groundwater are above the permissible limit for drinking and domestic purposes except for a few locations. The results of saturation index computation show that dissolution of gypsum, anhydrite, halite and silicate minerals occurs frequently across the study area, whereas the groundwater is supersaturated with regard to calcite and dolomite. Cross-plots show that weathering and dissolution of different rocks and minerals, ion exchange, reverse ion exchange and anthropogenic activities, especially agricultural activities, are effective in hydrogeochemistry of the study area.

- by Evangelos Tziritis
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- Hydrogeology, Hydrogeochemistry, Aquifer Characterization

Sungai Cikapundung adalah salah satu sungai stategis di Jawa Barat dengan populasi penduduknya tertinggi di Indonesia. Beriringan dengan masalah dalam pembangunan perkotaan, masalah yang terpenting adalah sumberdaya air sebagai sumber baku untuk pasokan utama air minum. Kontribusi airtanah utuk kebutuhan baku nyatanya makin lama semakin menurun kuantitasnya sehingga mendorong migrasi dari penggunaan airtanah ke air permukaan salah satunya air dari Sungai Cikapundung. Aktivitas manusia menjadikan sungai sebagai tempat penggelontoran kotoran dan pembuangan limbah domestik maupun sampah kota menjadikan penelitian ini sangat penting. Nilai alkalinitas dan elemen minor utama pada 9 lokasi penelitian di Sungai Cikapundung, menunjukan kecenderungan meningkat semakin ke hilir dengan variasinya masing-masing. Logam berat yang terdeteksi pada lokasi penelitian yaitu Arsenik (As), Timbal (Pb), dan Kadmium (Cd) dengan nilai yang tinggi menunjukan bahwa kualitas air di Sungai Cikapundung semakin hilir semakin buruk.Kata Kunci : Sungai Cikapundung, Kualitas Air, Logam Berat

- by sihem meziani
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- Geology, Hydrogeology, Informatics, Water quality

Forest Fire can cause considerable environmental damage and brings about significant change in the ecosystem of a region. The selected study area, Idukki Wildlife Sanctuary is prone to forest fires. The present study aims to demarcate forest fire risk zones of Idukki Wildlife Sanctuary in Kerala using GIS and Remote Sensing techniques. ArcGIS 9.3 and ERDAS Imagine 9.1 software tools are used for this study. The considered factors are land cover type, slope, distance from road, distance from settlement and elevation. The index maps of the selected factors are overlaid by GIS tools to prepare the risk map. A Fire Risk Index (FRI) method is used to prepare the forest fire risk zone map. In the prepared map, the area has been classified into five categories; very high, high, moderate, low, and very low risk zones. To validate the proposed method, the obtained results are compared with fire incidents of past 10 years. The obtained results indicate high accuracy.

- by Vinod PG
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- Biochemistry, Geomatics, Remote Sensing, Environmental Studies

Airtanah adalah air yang terdapat di bawah permukaan tanah pada lapisan batuan yang jenuh air, yang disebut sebagai akuifer. Airtanah dapat muncul ke permukaan tanah dengan berbagai cara yang umumnya dikontrol oleh kondisi geologi setempat, dan pemunculan airtanah ini disebut sebagai mata air. Sejak jaman dahulu, mata air telah dimanfaatkan oleh manusia sebagai sumber air untuk memenuhi kebutuhan hidupnya. Mata air dapat muncul di berbagai bentang alam, baik di dataran, perbukitan maupun pegunungan. Airtanah maupun mata air dapat ditemukan di berbagai macam batuan, seperti endapan sungai yang berupa pasir-kerikil-kerakal, endapan batuan karbonat yang berupa batugamping, ataupun pada endapan gunungapi yang berupa endapan lahar, breksi dan lava terkekarkan.

- by Heru Hendrayana
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- Groundwater, Groundwater Hydrology, Hydrogeochemistry, Groundwater Management

The study deals with water chemistry and its impact on the quality of groundwater in 10th of Ramadan City
which is among the new communities to the east of Nile Delta. This area is an intensive industrial settlement on
the perihelia of Cairo. All types of wastewater from industrial and domestic practices are discharged into three
unlined oxidation ponds to eliminate pollution. The study has been conducted to assess the extent of seepage to
groundwater from the ponds and how efficient they are for pollution reduction. The chemistry of groundwater
was outlined through the analysis of major cations and anions. Also, the pollution of groundwater was discussed
on basis of detection of minor elements such as heavy inorganic, biological organic and bacteriological
pollutants. The study indicated that most of the measured heavy metals such as Cd2+, Co2+, Zn2+, Mn2+, Pb2+ and
Ni2+ are present in groundwater within the international standard limit. Many pollutants such as Al3+, Fe3+, Cr3+
ammonia, S2-, BOD, COD, TOC and PO4
3- exceed the standard limit where their concentrations reached 2.4,
4.16, 0.03, 33.1, 72.7, 109.3, 802, 297.7 and 21.0 mg/l, respectively, in oxidation ponds and some groundwater
of eastern side which needs to be protected from this seepage processes

- by Abdel-hameed El-Aassar
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- Water resources, Groundwater Pollution, Hydrogeochemistry
- by Elango L
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- Hydrogeology, Environmetal Earth Science, Groundwater Contamination, Water Pollution

Groundwater from the La Paz arid coastal aquifer in Baja California, Mexico, is essentially the only source of drinking water for the local population and tourists, as well as irrigation water for agricultural needs. The intensive exploitation of the aquifer and water cycling has resulted in groundwater abatement (up to 10 m) and high salinity (up to *5800 mg l-1 ). A study using hydrochemistry, isotopic (deuterium, oxygen-18 and car- bon-14) and gaseous tracers (chlorofluorocarbons CFC-11, CFC-12, CFC-113), as well as multivariate statistics, was developed to elucidate groundwater composition, flow and occurrence. Groundwater is of meteoric origin, and a large proportion is subject to evaporation. The primary natural recharge is generated in the El Novillo and Las Cruces ranges, and groundwater subsequently flows in a SE–NW direction toward the coast. The initial water type is the result of discordant dissolution of silicate minerals and ion exchange on soils. In the lower plain portion, the aquifer system is recharged from irrigation return flow and sea- water intrusion, which significantly affects groundwater chemistry. Nitrate and chloride concentrations indicate that groundwater is highly affected by an overuse of fertilizers in agricultural activities, but there is little effect from urban activities. Seawater intrusion has progressed rapidly during the past decade, and the impact currently extends 13 km inland. Radiocarbon residence time calculations suggest that groundwater is modern, with the exception of Cha- metla and El Centerario sites in the central and western lowlands with ages of up to 5000 years. These waters indicate an additional recharge source for the upconing of fossil groundwater or regional flow.

- by Jürgen Mahlknecht and +1
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- Hydrogeology, Coastal Processes, Isotope Hydrology, Stable Isotopes

Taller del curso de Introducción a la Ingeniería Ambiental

- by Pedro Rau
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- Hydrochemistry, Hydrogeochemistry, Hidrogeology, Hidrologia

Unplanned abstraction of groundwater due to various land use land cover activities and variations in monsoonal rainfall have greatly affected the availability and quality of groundwater resources in semi-arid regions of India. In the present study, a study of the hydrogeo-chemical characteristics of groundwater was undertaken in the Sonipat district of Haryana in India together with the use of stable isotope (d 18 O and dD) measurements and GIS analysis. A total of 53 groundwater samples were collected from seven blocks of the district, and 14 water quality parameters and stable isotopes (d 18 O and dD) were analysed to infer hydrogeochemical processes taking place in the area. The integration of hydrochemistry with GIS is very helpful to understand the factors governing in the area. The majority of the samples showed Na–Cl type of hydrochemical facies. The trilinear plot for major cations and anions in groundwater indicates dominance of sodium, calcium, chloride and bicarbonate ions. Nitrate plumes in the groundwater appear to be migrating in groundwater from the central and southwestern parts of the area towards the urbanized areas. A total of 64% of the samples exceed the maximum permissible limit of 1.5 mg/L given by WHO for fluoride. Besides natural sources such as sil-icate and carbonate weathering, ion exchange, and reverse ion exchange, the leaching of surficial salts and untreated industrial wastes along with unregulated abstraction are contributing to poor groundwater quality in the study area.

- by muzzafar ahmad sheikh and +1
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- Geology, Hydrology, Hydrogeochemistry, Geochemical Modelling

Groundwater is the major source for drinking and irrigation purposes in the Central parts of Telangana. The demand for groundwater has recently increased due to intensive irrigation practices and population growth which in turn caused depletion of resource and deterioration of quality. In view of this, quality studies have been undertaken on 105 groundwater samples collected from the rock dominant semi-arid region of central Telangana and analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca 2+), magnesium (Mg 2+), sodium (Na +), potassium (K +), chloride (Cl −), sulphate (SO 4 2−), nitrate (NO 3 −), and fluoride (F −). Results revealed that 51% and 71% of groundwater has more than the maximum acceptable limits of fluoride (1.5 mg/L) and nitrate concentrations (45 mg/L), respectively, thus making the groundwater unsuitable for drinking purpose. Data plotted in Gibbs diagram reveal that the groundwater chemistry is primarily controlled by rock-water interaction. According to water quality index (WQI), 60% and 36% of groundwater samples fall in excellent and good categories for drinking purpose. A majority of groundwater samples fall in deep meteoric percolation and Na +-SO 4 2− types, but most belong to Ca 2+ –Mg 2+ –HCO 3 − , Na + –HCO 3 − facies, and few are of Ca 2+ –Mg 2+ –Cl − and Na + – Cl − facies. 90% of groundwater in the study region is well suitable for irrigation. It is advised that groundwater with high fluoride and nitrate concentration should be avoided for drinking purposes. Keywords Groundwater quality. Drinking and irrigation. Water quality index (WQI). Rock dominant semi-arid region. Telangana

- by Narsimha Adimalla
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- Hydrogeochemistry

Sierra de Gádor is a karsticmacrosystem characterized by highly complex geometry. The two main economic activities in this area – the highly profitable irrigated agriculture and tourism – are supported by water resources from Sierra de Gádor, hence the interest in understanding this aquifer system. The highly variable precipitation in the area is characteristic of the arid conditions. The aim of the study presented in this paper was to define the principal hydrogeochemical and isotopic characteristics of the area and to characterize the different types of freshwater, some of which are affected by the process of mixing with saltwater – particularly those at the
east andwest extremes of the Sierra de Gádor. The hydrogeochemical analysis enabled the principal geochemical processes occurring in the aquifer to be established. Thewaters can be grouped into four categories, each defined by a distinctive solute. Dissolution of dolomite determines the chemical composition of less mineralized water. Dedolomitization (dolomite dissolution together with calcite precipitation caused by dissolution of gypsum) becomes predominant when the water flows through interbedded gypsum. Marine intrusion results in highlymineralized waters and leads to base exchange reactions. The variation of δ18O content with altitude (−0.19‰/100 m) allows the main recharge areas to be determined: 2000–1500 m a.s.l., 1500–900 m a.s.l., and below900ma.s.l., according to the different hydrodynamic characteristics of each area. In some sectors, it is possible to detect the current recharge fromrainwater infiltration or seawater intrusion, based on its tritium content

- by Antonio Pulido-Bosch
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- Hydrogeochemistry

Maharashtra is predominantly an agrarian state and is underlain by Deccan Traps and other Precambrian suites of rocks. The rain-shadow drought prone region constitutes an important agroclimatic region of the state. In general, depleting groundwater levels and over-exploitation of the resource due to repeated droughts have characterized such areas. However, with the advent of irrigated agriculture, the water levels in some of the command areas began to rise leading to water logging. This scenario has left its imprints on groundwater quality trends. Study of geochemistry of groundwater indicates its evolution from a Ca+Mg > Na+K, HCO +CO > Cl+SO hydrogeochemical facies to Na+K 3 3 4 > Ca+Mg, HCO +CO > Cl+SO facies. Several irrigation water quality indices such as electrical conductivity, sodium 3 3 4

- by Raymond Duraiswami and +1
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- Hydrogeochemistry

The aim of this present study was to evaluate groundwater quality in the lower part of Nagapattinam district, Tamil Nadu, Southern India. A detailed geo- chemical study of groundwater region is described, and the origin of the chemical composition of groundwater has been qualitatively evaluated, using observations over a period of two seasons premonsoon (June) and monsoon (November) in the year of 2010. To attempt this goal, samples were analysed for various physico-chemical parameters such as temperature, pH, salinity, Na?,Ca2?, K?,Mg2?,Cl-, HCO3
- and SO4 2-. The abundance of
major cations concentration in groundwater is as Na[Ca[Mg[K, while that of anions is Cl[ SO4[HCO3. The Piper trilinear diagram indicates Ca–Cl2 facies, and according to USSL diagram, most of the sample exhibits high salinity hazard (C3S1) type in both seasons. It indicates that high salinity (C3) and low sodium (S1) are moderately suitable for irrigation purposes. Gibbs boo- merang exhibits most of the samples mainly controlled by evaporation and weathering process sector in both seasons. Irrigation status of the groundwater samples indicates that it was moderately suitable for agricultural purpose. ArcGIS 9.3 software was used for the generation of various the- matic maps and the final groundwater quality map. An interpolation technique inverse distance weighting was used to obtain the spatial distribution of groundwater quality parameters. The final map classified the ground quality in the study area. The results of this research show that the development of the management strategies for the aquifer system is vitally necessary.

- by Venkatramanan Senapathi
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- Hydrogeochemistry, India, Groundwater Quality, Interpolation

A study carried out to evaluate hydrogeochemical characteristics of groundwater in the Cape Flats identified the geochemical processes and their relation to groundwater quality. The distribution of salinity, trends in major ions and ionic ratios imply that groundwater chemistry is largely controlled by a combination of surface and near-surface processes. The groundwater is characterised by Ca-Mg-HCO 3 , Ca-SO 4 and Na-Cl. There is little difference in chemistry between the older underlying Malmesbury Formation and the Cape Flats nonetheless in comparison with the Cape Granite, the composition (e.g. total dissolved solids) is tentimes higher. Sources and mechanisms of salinization were investigated • using geochemical techniques. The analysis and interpretation of longterm groundwater monitoring data revealed that salinity and nitrate contamination are potential threats to groundwater usability. High levels of chloride concentration in wells within 8 kilometres of the coast of False Bay is contributing to the deterioration of groundwater quality and could limit the quantity of available sustainable groundwater in this area.

A hydrochemical study on the coastal aquifers were collected initiated to determine the factors affecting the groundwater chemistry in South India. 48 groundwater samples from bore wells during post monsoon period. The samples were measured for in situ parameters and major ions following the standard procedures. The analyzed results were further interpreted using geochemical plots, ionic ratios, water quality indices, geo-chemical modeling and statistics. pH values in the groundwater ranged from 6.6 to 8.0 and alkaline in nature. The average value of EC was 7155 μS/cm and higher values were mostly distributed along the coastal region of the study area. From the Piper plot, hydrochemical evolution path was identified, from Ca−HCO 3 (recharge waters) to mixed Ca-Mg-Cl (reverse ion exchange waters) through Ca-Cl types (leachate waters), indicating the reverse ion exchange and seawater intrusion. Saturation index reflected that Calcite was oversaturated due to availability of Ca and HCO 3 ions. Factor analysis further improved the understanding of the major controlling hydrochemical processes for groundwater chemistry. The hydrochemistry of the coastal aquifer was affected by several factors such as dissolution, water-rock interaction, reverse ion exchange, seawater intrusion, and influence of minor agricultural. The water quality assessment showed that the concentration of most of the parameters exceeded the standards limit, and considered as unsuitable for drinking purposes. But they are inferred to be suitable for agricultural purposes according to SAR, Na%, RSC and PI.

- by Venkatramanan Senapathi
- •
- Hydrogeochemistry

In this study first locations of past occurrence were identified and an inventory form were created and integrated to GIS to derive landslide inventory map predictors. Secondly predictors causing landslides were identified from report of past landslides. Thirdly thematic maps of the identified predictors namely geomorphology, geology, drainage, rainfall, lineament, road, railway, soil, land use/land cover, slope and aspect were derived using Geographical Information System (GIS). Finally based on relative importance of factors and their categories influencing landslide susceptibility weights and ratings of predictors were calculated using two multi criteria approaches namely Analytical Hierarchy processes (AHP) and Spatial Multi Criteria Evaluation (SMCE). Weights and rating obtained for factors and predictors were overlayed using weighted overlay tool of GIS software to generate LS map with classified five zones namely very low, low, moderate, high and very high. Using field check and Receiver Operating Curve (ROC) the LS map were validated, using validate location set Area Under the Curve (AUC) AHP of 95.98% and SMCE of 98.86% were determined .

- by Dr Elangovan K
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- Hydrogeochemistry, Remote sensing and GIS, Groundater Resources

A total of 20 groundwater samples were col-lected from both dug and bore wells of southern Tiruchi-rappalli district and analyzed for various hydrogeochemical parameters. The analyzed physicochemical parameters such as pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, carbonate, sulfate, chloride, nitrate, and fluoride are used to characterize the groundwater quality and its suitability for drinking and irrigational uses. The results of the chemical analysis indicates that the groundwater in the study area is slightly alkaline and mainly contains Na ? , Ca 2? , and Mg 2? cations as well as HCO 3 2-, Cl -, SO 4 2-and NO 3 -anions. The total dissolved solids mainly depend on the concen-tration of major ions such as Ca, Mg, Na, K, HCO 3 , Cl, and SO 4 . Based on TDS, 55 % of the samples are suitable for drinking and rest of the samples are unsuitable for drinking. The total hardness indicates that majority of the ground-water samples are found within the permissible limit of WHO. The dominant hydrochemical facies for groundwater are Ca–Mg–Cl, Ca–HCO 3 , and Ca–Cl type. The USSL graphical geochemical representation of groundwater quality suggests that majority of the water samples belongs to high medium salinity with low alkali hazards. The Gibb's plot indicates that the groundwater chemistry of the study area is mainly controlled by evap-oration and rock–water interaction. Spearman's correlation and factor analysis were used to distinguish the statistical relation between different ions and contamination source in the study area.

- by Chandrasekar N and +1
- •
- Groundwater Pollution, Hydrogeochemistry, Groundwater Quality

This study is to assess the hydrogeochemical characteristics of groundwater at the deltaic region of the Nakdong River Basin in the Busan Metropolitan City of Korea. The study area is covered by the Quaternary sedimentary deposits and the Cretaceous granites associated with unconformity. The thick sedimentary deposits consists of two aquifers, i.e., unconfined and confined aquifers on the basis of clay deposit. Groundwater samples were collected from seven boreholes: two from unconfined aquifer and five from confined aquifer systems during the wet season of 2017 year. ORP and DO indicates that the groundwater of the unconfined aquifer exists in the oxidization condition and that of the confined aquifer pertains in the reduction condition. Piper's trilinear diagram shows CaSO 4 type for groundwater of the unconfined aquifer, and NaCl type for that of the confined aquifer. Ionic concentrations of groundwater increase in the confined aquifer because of direct and reverse ion exchange processes. Carbonate weathering and evaporation are other mechanisms in the water-rock interaction. Saturation indices of dolomite and calcite are observed as oversaturated, while halite reveals undersaturation. Hierarchical cluster analysis (HCA) exhibits that cluster 1 and cluster 2 represents the properties of groundwater in unconfined and confined aquifers, respectively. Factor analysis shows that groundwater of the confined aquifer is much influenced by seawater, and includes heavy metals of iron and aluminum. Groundwater samples in unconfined and confined aquifers are located at the rock weathering and evaporation zones in the Gibbs diagram. Inverse geochemical modeling of PHREEQC code suggests that carbonate dissolution and ion exchange of major ions are the prevailing geochemical processes. This comprehensive research provides the distinguished hydrogeochemical characteristics of groundwater in confined and unconfined aquifer systems of the Nakdong River Basin in Busan City, Korea.

- by Venkatramanan Senapathi and +2
- •
- Hydrogeochemistry

This study was conducted on the hydrochemistry of shallow groundwater and surface water in the Ndop plain, North West Cameroon. The objectives were to determine the physico-chemical characteristics of water, controls on water chemistry and suitability for drinking and irrigation. Forty-six shallow groundwater and 26 surface water samples were investigated. Field measurements of physical parameters were preceded by chemical analyses of the samples for major ions and F -. About 69% of the water sources had pH values below 6.5, classifying the water as barely acidic. Electrical conductivity (<282 µS/cm) and total dissolved solids (<183 mg/l) were low suggesting low-mineralised and freshwater. The relative abundance of major ions (meq/l) was Na 2+ >Ca 2+ >Mg 2+ >K + for cations and HCO 3 ->>NO 3 -≥Cl ->SO 4 2for anions. Major ion concentrations were low, and within the WHO guidelines for drinking water, but Fconcentrations were much lower (<0.39 mg/l) and below guideline value. Main water types and proportions were Na-HCO 3 (53 %), Ca-HCO 3 (35 %) and a mixed Na-Ca-HCO 3 (11%). Predominant processes influencing water chemistry were incongruent dissolution of silicate minerals and cation-exchange of Na + in rocks for Ca 2+ in water. The low major ion concentrations indicated low water-rock interactions and short residence time. The analysed water was suitable for irrigation.

- by Mengnjo Jude Wirmvem and +1
- •
- Paleoclimatology, Hydrogeochemistry, Environmental Geochemistry, Isotopoe Hydrology

A quantitative assessment of annual soil erosion by water in the northern part of Kirkuk Governorate, north of Iraq was investigated through integration of remote sensing, GIS and empirical RULSE soil erosion model. The five factors of RULSE model (rainfall erosivity R, soil erodibility K, slope length and steepness LS, crop management C, and practice factor P) were derived from different resources such as field survey, archival data, digital elevation model, and LANDSAT 8 multi-bands imagery. The annual soil erosion loss was estimated by multiplying the five factors in raster format using raster calculator of ArcGIS 10.2 software. The estimated annual soil losses rate for the study area ranges from 0 to 245 (t ha-1 yr-1) with an average of 2 (t ha-1 yr-1). The value ranges were classified into four categories: minimal, low, moderate, high soil erosion hazard zones using four classification schema: quantile, natural breaks, geometric, and standard deviation. Due to the similarity of results, the comparison was carried out between two schemas: natural breaks and geometric. The area covered by minimal-low soil hazard zones extends over an area of about 88% and 99% based on geometric and natural breaks schema, respectively. In turn, the moderate-high soil hazard zones cover only very small area (0.3%) based on natural breaks and relatively small area (12%) depending on geometric scheme. In general, both method results indicate that hazard of soil erosion is low in the study area. The spatial pattern of classified soil erosion rate indicates that the areas at moderate to high risk is located in the northeast and very small area in the east, while the minimal to low zones cover the other parts. The obtained results of could be useful to implement soil conservation practices in the study area.

- by Hussein B Ghalib
- •
- Hydrogeology, Hydrology, Water resources, Stable Isotope Geochemistry

The chemical quality of groundwater of Bushehr, southwest of Iran, was assessed for its suitability for drinking purposes. Hydro-geochemical studies were carried out in this area to identify the geochemical processes and their relation to groundwater quality. A total of 19 water samples were collected from the aquifer. The samples were then analyzed for different physicochemical properties, such as pH, total dissolved solids (TDS), total hardness (TH), calcium, magnesium , carbonate, bicarbonate, sulfate, and chloride concentrations. In this study, the average TDS content was in the range of 4419–10,066 mg l/l, and other important parameters of water, such as TH (1200–3500 mg l/1) and chloride (1046–3855 mg l/1), were also higher than the maximum permissible limits specified by WHO. On the basis of concentrations of major elements, studies of the study area showed that the total samples collected are unsuitable for drinking. Linear increase in sodium and chloride of the total dissolved ion indicated a dissolution of halite in the study area. Salinity of the aquifer is mainly a result of the Dalaki River recharge, dissolution of evaporated minerals intrafor-mation, and also agricultural returned water. The dissolution of evaporite minerals, such as halite and gypsum, has increased the concentration of total dissolved solids and of sulfate in the Shahpour River and also groundwater entering the study area has caused salinity in this river.

- by z Ahmadnejad and +1
- •
- Hydrogeochemistry

Abstr act Var ious geochemical processes within the aquifer and anthropogenic activities in the area influence the spatial and tempor al var iations of sur face and groundwater quality. The pr esent study on seasonal var iati on and i nfluence of ur ani um mi ner al i sed zones i n gr oundwater quality ar ound K oppunur u based on monthly sampling fr om Febr uar y 2010 to Januar y 2011 indicates pr esence of 2–3388 ppb U and show or der of abundance of maj or cations as Na + >Ca 2+ >K + >M g 2+ while that of anions as HCO 3 – >Cl – >SO 4 2– >CO 3 2–. M ixed Ca–M g–Cl and Ca–HCO 3 ar e the dominant gr oundwater types in this ar ea. M ar ginal decr ease in Eh and cor r esponding incr ease in pH is quite appar ent dur ing post-M onsoon season. Na and SO 4 exhibit pr ogr essively decr easing tr end fr om pr e-to post-M onsoon season whi le r el ativel y hi gher content of CO 3 dur i ng post-M onsoon season suggests dissolution of calcar eous lithounits of Nar j i For mation by gr oundwater. High TDS, its linear ity with conductivity and str ong positive cor r elation among Na, K , Cl, SO 4 and TDS for all seasons ar e mainly due to low annual r ainfall/gr oundwater r echar ge and dominance of evapotr anspir ation process. Pr incipal Component Analysis (PCA) and Gibbs r atio plot suggest r ock–water inter action as maj or contr ibutor to the salinity and var iation in water chemistr y. M aj or ity of groundwater samples indicate negative Chloroalkaline indices (CAI) suggesting cation–anion exchange r eactions, wher ein M g and Ca fr om water ar e exchanged with Na and K available in silt/clay layer s of Banganapalle For mation. Based on BI S and WHO pr escr ibed limits, studied gr oundwater has limited suitability for human consumption on the grounds of moder ate to high har dness, salinity and TDS. However, the concentr ation of toxic element such as F is well within the desir ed limits, except one sample (upto 2.1ppm), while four samples show higher U content thr oughout the year as compar ed to the per missible limits of 30 ppb. Similar ly, pr edominance of low to medium SAR with medium to high conductivity categor izes the studied gr oundwater as suitable for ir r igation pur pose. K eywor ds: Groundwater geochemistr y, Ur anium, Pr incipal Component Analysis (PCA), Sodium Absor ption Ratio (SAR), Chloroalkaline I ndex (CAI), Water potability, Guntur. Groundwater geochemistry is primarily controlled by the aquifer lithology, rock–water chemical interacti on processes and cl imati c factors l i ke evaporati on, preci pi tati on, and evapotranspiration, which vary with changing seasons. Secondary controls, like interaction with disintegrated products of rock weathering, presence of sulphide species, tailings and mine dumps may l ead to the acidi fi cati on of the

- by RAHUL BANERJEE
- •
- Hydrogeochemistry, Uranium exploration

The groundwater provinces of eastern Maharashtra are at the crossroads so far as the groundwater resources are concerned. Overexploitation of groundwater resources in the orange growing belts of Amravati and Nagpur region has led to the widespread decline of the water table that has sounded warning bells to planners and policy makers alike. Farmers are forced to draw water from deeper levels to save their orange crop, an activity that has increased the cost on drilling, energisation and pumping device. Until now, mining was considered as a source of sustenance to the local population. However, with widespread dewatering in mining areas, groundwater based water supplies to villages, affected by mining activity, is no more sustainable. High fluoride contents in the groundwater from the Precambrian, Proterozoic and Deccan Trap terrains of eastern Maharashtra remain a high priority area, as this poses a serious health threat to the rural population living in the region. Other groundwater related problems include high contents of iron in groundwater and the ever lurking threat of industry related pollution. The paper emphasises that, although geology plays a vital role in various issues related to groundwater in the region; proper management and mitigation can reduce the ill effects of nature and ensure sustainability.

- by Raymond Duraiswami
- •
- Hydrogeochemistry

. Hidrogeología del sistema lagunar del margen este del Salar de Atacama (Chile). Boletín Geológico y Minero, 121 (4): 357-372 RESUMEN Se propone un modelo conceptual hidrogeológico del sistema lagunar del margen oriental del Salar de Atacama (Chile), integrando datos climáticos, geológicos y geomorfológicos, piezométricos, químicos e isotópicos. El estudio establece los procesos que definen la evolución hidrogeoquímica del agua, desde las zonas de recarga del margen E como agua relativamente salobre hasta su incorporación como salmuera al acuífero del núcleo salino. Los principales mecanismos que explican la composición del agua son la evaporación y procesos de disolución y precipitación de sales que ocurren a lo largo de la dirección de flujo en las zonas de descarga del acuífero aluvial en la zona de interacción con la cuña salina. La interacción con el substrato particular del sector (litologías detríticas y evaporíticas localmente enriquecidas en materia orgánica) también modifica la composición química de las aguas, interviniendo eficazmente en los mecanismos de alteración y / o crecimiento de las costras evaporíticas. Paralelamente, la caracterización hidrogeológica de estos materiales (presencia de niveles de baja permeabilidad en el subsuelo), es uno de los parámetros clave para justificar la presencia y el mantenimiento de las lagunas y humedales. En este sentido, se han propuesto tres mecanismos diferentes para la recarga de las principales lagunas: (1) descarga de agua subterránea salina procedente de los acuíferos vulcano-detríticos del margen E del Salar, (2) alimentación por vías de drenaje superficial procedentes del margen N (canal Burro Muerto), y (3) recarga mixta subterránea y superficial, con un régimen estacional variable.

- by Jordi Guimerà
- •
- Hydrogeology, Hydrogeochemistry

Aji-Chay River is one of the most important surface reservoirs of northwest of Iran, because it passes through Tabriz city and discharges to Urmia Lake, one of the largest permanent salty lakes in the world. The main objectives of the present study are to evaluate its overall water quality and to explore its hydrogeochemical characteristics , including the potential contamination from heavy metals and metalloids such as Co, Pb, Zn, Cd, Cu, Cr, Al and As. For this purpose, 12 water samples were collected from the main river body and its tributaries within Tabriz plain. The Piper diagram classified water samples mainly into Na–Cl and secondary into Ca–HCO 3 and mixed Ca–Mg–Cl types, denoting a profound salinization effect. The cross-plots showed that natural geochemical processes including dissolution of minerals (e.g., carbon-ates, evaporites and silicates), as well as ion exchange, are the predominant factors that contribute to fluvial hydro-geochemistry, while anthropogenic activities (industrial and agricultural) impose supplementary effects. Cluster analysis classified samples into two distinct clusters; samples of cluster B appear to have elevated electrical conductivity (EC) values and trace metals concentrations such as Co, Pb and Cd, while SiO 2 and Zn are low in comparison with the samples of the cluster A. The main processes controlling Aji-Chay River hydrogeochemistry and water quality were identified to be salinization and rock weathering. Both are related with geogenic sources which enrich river system with elevated values of Na ? , Cl-, Ca 2? , Mg 2? , K ? , SO 4 2-and EC as a direct effect of evaporites leaching and elevated values of Pb and Cd as an impact from the weathering process of volcanic formations. According to the US salinity diagram, all of the water samples are unsuitable for irrigation as having moderate to bad quality.

- by Evangelos Tziritis
- •
- Hydrogeochemistry

In order to understand and mitigate the deterioration of water quality in the aquifer system underlying Guadalajara metropolitan area, an investigation was performed developing geochemical evolution models for assessment of groundwater chemical processes. The models helped not only to conceptualize the groundwater geochemistry, but also to evaluate the relative influence of anthropogenic inputs and natural sources of salinity to the groundwater. Mixing processes, ion exchange, watererockewater interactions and nitrate pollution and denitrification were identified and confirmed using mass-balance models constraint by information on hydrogeology, groundwater chemistry, lithology and stability of geochemical phases. The watererock interactions in the volcanic setting produced a dominant NaeHCO 3 water type, followed by NaeMgeCaeHCO 3 and NaeCaeHCO 3. For geochemical evolution modeling, flow sections were selected representing recharge and non-recharge processes and a variety of mixing conditions. Recharge processes are dominated by dissolution of soil CO 2 gas, calcite, gypsum, albite and biotite, and Ca/Na exchange. Non-recharge processes show that the production of carbonic acid and Ca/ Na exchange are decreasing, while other minerals such as halite and amorphous SiO 2 are precipitated. The origin of nitrate pollution in groundwater are fertilizers in rural plots and wastewater and waste disposal in the urban area. This investigation may help water authorities to adequately address and manage groundwater contamination.

Combined assessments from different methodologies, including hydrogeo-chemical analysis, multivariate statistics and stable isotopes, were used in order to characterize the groundwater resources of a heterogeneous aquifer system in central Greece and to evaluate the overall environmental regime. Results outlined the driving factors that chiefly control groundwater chemistry and delineated the major pathways of groundwater flow. Following the results of the combined assessments, hydrogeochemistry is influenced both by geogenic and anthropogenic factors including the geological substrate, intense agricultural activities and ongoing geochemical processes which impact the concentrations of redox sensitive agents like NO 3 , Fe, Mn and SO 4. Stable isotope evaluations supplemented the above assessments by providing critical information for the hydrodynamics of the heterogeneous aquifer system. Evaporation is the main factor influencing the isotopic composition of water resources, in addition to the slow percolation rates of the thick unsaturated zone. Comparisons between d 18 O and dD values for surface and groundwater samples revealed an interaction among water systems through the developed karstic network and/or the riverbeds of higher permeabilities. Eventually, the integrated conceptual approach of diverse methodologies was applied successfully for the identification of hydrogeological and hydrogeochemical assessments in the case of Kopaida basin; evaluations were cross-confirmed and supplemented when needed, hence providing essential information for strategic planning and water resources management.

- by Evangelos Tziritis and +1
- •
- Hydrogeology, Multivariate Statistics, Stable Isotope Geochemistry, Hydrogeochemistry

The present study investigates the hydrogeochemical regime of a complex aquifer system in a highly cultivated area of Thessaly, central Greece. To do so, totally forty (40) groundwater samples were collected for three aquifer units with diverse geological and hydrogeological attributes and analyzed for 77 parameters. Data processing was accomplished with the joint use of classic hydrogeochemical techniques including major ion molar ratios and graphical interpretation, as well as multivariate statistical methods including R-mode factor (FA) and hierarchical cluster analysis (HCA). Results showed that major ion hydrogeochemistry is characterized by the prevalence of calcium (median = 81 mg/L) and bicarbonates (median = 308 mg/L) in the following descending order of concentrations for cations Ca2+>Mg2+>Na+>K+ and anions HCO3−>NO3−>SO42−>Cl−, respectively. Nitrate values are elevated (median = 23 mg/L), especially in the porous quaternary aquifer, indicating the ongoing agricultural impact from the excessive use of nitrogen fertilizers and manure. The results of multivariate statistics highlighted four factors that chiefly control 81.4 % of overall hydrogeochemistry, related with both geogenic and anthropogenic impacts. The geogenic impact is mainly attributed to the geological substrate and secondarily to the ongoing geochemical (redox) conditions which in turn enrich or deplete groundwater solution with different ions; anthropogenic impact is mainly related with the extensive agricultural practices which favor nitrate enrichment and salinization due to irrigation water return flow.

Hydrogeochemical investigations were carried out in Salem taluk of Tamil Nadu, India to identify the suitability of water quality and the major geochemical processes that regulate groundwater chemistry. A total of 23 groundwater samples were collected from open wells in pre-monsoon (May 2013) and post-monsoon (December 2013) and analyzed for pH, EC, TDS, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, nitrate, sulfate and fluoride. Geochemical data were interpreted using SAR, Na %, RSC, CAI & Wilcox diagram which revealed that 85 % of the groundwater is fit for domestic and irrigation purpose. In Pre monsoon and Post monsoon seasons, most of the samples are Ca-Mg-Cl type and some samples fall in Ca-HCO3 and Na-Cl type.

- by Venkatesan .D
- •
- Hydrogeochemistry

The Indian state of Odisha has a number of
thermal springs. These thermal springs are located at eight
places (Attri, Tarabalo, Deulajhari, Magarmuhan, Bankhol,
Badaberena, Taptapani and Boden) and belong to Mahanadi
Geothermal Province, which is an Archean/Pre-
Cambrian Geothermal Province. The thermal water discharging
from these springs shows moderately acidic to
moderately alkaline character (pH: 5.05–8.93) and the
temperature ranges from 28 (Boden) to 58 C (Tarabalo).
Total dissolved solids (TDS) also shows a wide variation
between 16.9 (Bankhol) and 595 mg/L (Deulajhari). A
wide variation in the chemical characteristics of the thermal
waters has been observed as they are located in different
geological settings. Based on water chemistry, all the
thermal springs can broadly be grouped into three water
types: Na–Cl, Ca–HCO3 and Na–HCO3. The thermal
spring water from Attri, Tarabalo and Deulajhari belongs to
Na–Cl water type which is due to the circulation through
granitic rocks. Higher concentrations of Cl and F in these
thermal waters further suggest limited mixing and longer
residence time as compared to the other areas where Ca–
HCO3 and Na–HCO3 water types were found. Anion
variation diagram clearly indicates that the thermal waters
from Attri, Tarabalo and Deulajhari are fast ascending and
fall in the mature water field; thus, their chemical signatures
can be used to determine the reservoir temperature.
However, in other areas, water chemistry is shaped by
near-surface groundwater mixing processes and thus the
chemical geothermometers may not be applicable to
determine the reservoir temperature. No appreciable temporal
variations have been observed in the water chemistry
of the thermal waters.

- by Horthing V Zimik
- •
- Hydrogeochemistry, Geothermal Energy

The presence of uranium (U) in potable groundwater must be treated with extreme care because of its health concerns. The study area consists of complex lithology and various land use activities including natural and anthropogenic processes. The present study aims to assess the seasonal distribution, probable sources and factors responsible for U mobilization in groundwater and provides a holistic picture of geochemical processes in the study area. To achieve these objectives, a total of 680 groundwater samples were collected during four different seasons (pre-monsoon, southwest monsoon, monsoon and post-monsoon). The samples were collected with lithological differences to determine the effects of natural geochemical processes in addition to the anthropogenic impacts. The trend of anions reflected the following order during PRM and NEM: Cl > HCO 3 − > NO 3 > SO 4 > PO 4 , and cations Na > Ca > Mg > K during PRM and SWM. The U concentration in the samples ranged from 10 to 70 ppb, being higher during the NEM season. The samples were classified into three groups based on U concentration (< 10 ppb, 10-15 ppb and > 15 ppb) and studied using various geochemical diagrams, statistical application, thermodynamic study and saturation states for different minerals. The maximum concentration of U in groundwater during different seasons reflects that NEM > POM > SWM > PRM. The higher U values were observed in the hornblende-biotitegneiss irrespective of the season. U in groundwater migrates away from the source due to its high solubility, where it tends to form complexes, especially in the presence of phosphates or carbonates. Analysis of the data shows that the majority of the samples in the monsoon season reflect dilution and recharge processes. In contrast, during SWM and PRM, ion exchange and anthropogenic influences predominate the processes. The PCA study shows that secondary salt leaching, weathering, anthropogenic influences and ion exchange play a significant role in determining the groundwater chemistry in this region.

- by Venkatramanan Senapathi
- •
- Hydrogeochemistry, Uranium, Groundwater Quality

Assessment of groundwater quality is an important aspect of water security, which is the key to ensure sustainable development. The objective of the study is to bring out an integrated approach for assessment of groundwater quality for drinking and irrigation purposes. Gogi region, Karnataka, India was chosen as the study area due to the effect of the presence of medium-grade uranium deposits. An integrated approach including the concentration of major ions, trace elements and uranium was employed to investigate the quality of groundwater. Totally, 367 groundwater samples were collected periodically from 52 wells distributes over the Gogi region and the parameters such as pH, electrical conductivity, total dissolved solids (TDS), Ca 2+ , Mg 2+ , Na + , K + , Cl − , SO 4 2− , NO 3 − , Zn, Pb, Cu, and uranium of groundwater were analysed. Spatial distribution maps of various chemical constituents were prepared using geographic information system and its temporal variation was plotted in box and whisker plot. The analytical data were compared with Bureau of Indian Standards and World Health Organisation standards to determine drinking water quality and parameters such as salinity hazard, alkalinity hazard and percent sodium were estimated to assess the irrigation quality. Multivariate statistical analysis by cluster analysis was also performed which results in two groups consisting of wells with unsuitable water for drinking purposes. Groundwater in about 15% of the sampling wells were found to be unsuitable for domestic purpose based on TDS and about 17% were unsuitable based on uranium concentration. Finally, integration of spatial variation in TDS and uranium reveals that about 25% of the wells were unsuitable for domestic purposes. It is suggested that such an integrated approach needs to be formulated considering major ions, trace elements and radioactive elements for proper assessment of water quality. Implementation of managed aquifer recharge structures in the study area is suggested since it would potentially reduce the concentration of ions.

- by Manoj Subramanian and +2
- •
- Groundwater, Hydrogeochemistry, Uranium, Trace Elements

Groundwater is one of the most valuable natural resources in Peddavagu in Central Telangana (PCT). Most of the PCT region population rely on groundwater for especially drinking purposes. For this reason a thirty-five groundwater samples were collected, analysed various physico-chemical parameters including F −. The range of fluoride concentration 0.6–3.6 mg/L in Zone-I and 1–3.5 mg/L in Zone-II. pH of groundwater is from 7.1 to 8.4 and 7.3 to 8.3 in Zone-I and Zone-II respectively. Fluoride shows a significant correlation with pH, HCO 3 − , and Na + , which may leads to enhance the fluoride content in groundwater. Insignificant relationship between F − and NO 3 − suggests no influence of anthropogenic sources for F − content in groundwater. The results of the relationship between Na + +K + versus total cations (TZ +), Ca 2+ +Mg 2+ versus HCO 3 − +SO 4 2− describes silicate weathering is prevails in the groundwater chemistry. The dominance of the water types Na +-HCO 3 − > Ca 2+-Mg 2+-HCO 3 − > Ca 2+-Mg 2+-SO 4 2− Cl − >Na +-Cl −. Gibbs plot employed to differentiate the controlling mechanisms of hydrochemistry, which showed that rock water interaction is the governing process. Na +-HCO 3 − , alkaline nature water and rock water interaction can leads to elevate fluoride content into groundwater in the study region. Thereby, most of the region people suffer with fluorosis problem, due to intake of higher fluoride content of drinking water. Therefore, the study region population may avoid such untreated water for drinking and adopt a suitable method to reduce the fluorosis problem in future.

- by Narsimha Adimalla
- •
- Hydrogeochemistry, Groundwater Modelling
- by Mohamed Attwa
- •
- Hydrogeochemistry

A model has been established on the origin and extent of fresh groundwater, salty paleowaters and saltwater from recent seawater intrusions in the Red River flood plain in Vietnam. This was done with geological observations, geophysical borehole logging and transient electromagnetic methods. Salt paleowater is present up to 50-75km from the coastline, with occurrence controlled by the Holocene transgression. A density-driven leaching of salty porewater has occurred from high-permeability Holocene sediments into underlying Pleistocene deposits, whereas diffusion has dominated in low-permeability layers. In the Pleistocene aquifer, the highest content of dissolved solids is found below two intrinsic valleys with Holocene marine sediments and along the coastline. Recent intrusion of saltwater from the South China Sea is observed in shallow groundwater 35km inland, probably a result of transport of salty water inland in rivers or leaching of paleowaters from very young near-coast marine sediments. The observed inverted salinity profile, with high saline water overlying fresher groundwater, has been formed due to the global eustatic sea-level changes during the last 8,000-9,000years. The proposed model may therefore be applicable to other coastal aquifers, with a proper incorporation of the local geological environments.

- by nhan lu
- •
- Environmental Engineering, Geology, Hydrology, Hydrogeochemistry

A preliminary investigation of hydrogeochemistry, metals and mineral saturation indices were carried out in Nakdong surface water and adjacent deltaic groundwater in Busan, Korea in order to assess their suitability in relation to domestic and agricultural uses. Further, this study was conducted to bring out the relationship and the behavior of different Saturation Indices (SI) of carbonate, sulphate and oxide minerals. One surface water and two groundwater samples were collected, and hydrogeochemical nature was investigated by analyzing the major cations (Ca, Mg, Na, K) and anions (Cl, HCO 3 , SO 4 , NO 3, F) with some metals (Fe, Mn, Cu, Zn, Sr). Piper diagram showed that water samples fell in the field of mixed Ca-HCO 3 type followed by Na-Cl water types. Hydrogeochemical processes controlling water chemistry were water-rock interaction rather than evaporation or precipitation. In Wilcox diagram, water samples fell in low to very high sodium and salinity hazards indicating the suitability for agricultural purpose. Geochemical model, WATEQ4F was used to calculate the Saturation index (SI) of minerals. The SIs of carbonate, sulphate and oxide minerals represented undersaturated and equilibria state. Interpretation of geochemical data suggested that weathering, ion exchange reactions, and SI were the dominant factors that determined the major ionic compositions of groundwater in the study area.

- by S.Y. Chung
- •
- South Korea, Water quality, Hydrogeochemistry, River water

Mounding often occurs beneath engineering structures designed to infiltrate reuse water. AQTESOLV software and a spreadsheet solution for Hantush, together with soil moisture water balance (SWAGMAN farm model), were used for quantitatively predicting the height and extent of groundwater mounding underground to assess the groundwater-flow simulations of infiltration from a hypothetical irrigation site. Horizontal and vertical permeability, aquifer thickness, specific yield, and basin geometry are among the aquifer and recharge properties inputs. For 2.2 ha sites, the maximum heights of the simulated groundwater mound ranges up to 0.29 m. The maximum areal extent of groundwater mounding measured from the edge of the infiltration basins of 0.24 m ranges from 0 to 75 m. Additionally, the simulated height and extent of the groundwater mounding associated with a hypothetical irrigation infiltration basin for 2.2 ha development may be applicable to sites of different sizes, using the recharge rate estimated from the SWAGMAN farm model. For example, for a 2.2 ha site with a 0.0002 m/day recharge rate, the irrigation infiltration basin design capacity (and associated groundwater mound) would be the same as for a 1.1 ha site with a 0.0004 m/day recharge rate if the physical characteristics of the aquifer are unchanged. The study claimed that the present modelling approach overcomes the complications of solving the Hantush equation for transient flow. The approach utilised in this study can be applied for other purposes such as measuring the feasibility of infiltrating water, attenuation zone, risk mitigation essential for decision-makers and planning regulators in terms of environmental effects and water use efficiency.

Pegunungan vulkanik mempunyai peran yang sangat besar dalam siklus aliran air tanah. Kapasitasnya sebagai daerah imbuhan, menjadikan bentang alam ini sebagai salah satu objek utama dalam usaha perlindungan air tanah. Tingginya tingkat keanekaragaman formasi geologi, menjadikan aliran air tanah di bentang alam ini memiliki keunikan tersendiri dibanding bentang alam yang lain.
Gunung Bromo merupakan salah satu gunungapi aktif di Indonesia. Lereng timur laut Gunung Bromo, secara administratif berada di wilayah Kabupaten Probolinggo dan merupakan daerah penelitian yang akan diulas dalam tulisan ini. Keberadaaan daerah penelitian yang berada di lereng pegunungan vulkanik, ternyata tidak serta merta menjamin tercukupinya kebutuhan air bersih bagi penduduk setempat. Berdasarkan data PDAM Kab. Probolinggo tahun 2013, terdapat tiga desa di tiga kecamatan yang hampir setiap tahun mengalamai bencana kekeringan.
Dalam penelitian ini, digunakan pendekatan dengan pengamatan fisik geologi lapangan untuk mengetahui hidrostratigrafi daerah penelitian, pengamatan hidrogeokimia air tanah untuk mengetahui fasies air tanah, dan pengamatan isotop 2H untuk mengetahui lokasi daerah imbuhan air tanah. Dari hasil pengamatan ini, diketahui bahwa hidrostratigrafi lereng timur laut Gunung Bromo sangat dipengaruhi oleh sejarah geologi Gunung Bromo yang mana pada sekitar 150.000 tahun yang lalu mengalami letusan besar membentuk kaldera Ngadisari dan lembah Sapikerep. Hal ini menyebabkan fasies air tanah pada daerah penelitian memiliki perbedaan dengan lereng Gunung Bromo di sisi lain walaupun masih dalam satu zona fasies stratovulkanik. Selain itu, adanya daerah rawan kekeringan di lokasi penelitian juga sangat berhubungan dengan material vulkanik akibat dari letusan tersebut.

- by Heru Hendrayana
- •
- Hydrogeology, Isotope Hydrology, Groundwater, Groundwater Hydrology