Arsenic content in groundwater and soils of Ballia, Uttar Pradesh

Arsenic pollution in groundwater now appears to be spreading in several parts of India. Ballia district in Uttar Pradesh has a dubious distinction of being another district with groundwater having 16-470 ppb of arsenic. The source of arsenic is not related to sulphide minerals. Due to the prevailing agricultural practice, soils are accumulating large percent of arsenic. Organic matter in the soils is concentrating 15-22% arsenic. Percolating water with high Fe and Mn may increase the arsenic content in groundwater by several folds than that is observed at present

Hydrogeochemistry and groundwater quality in Champhai, Mizoram, North Eastern India

An effort has been made probably for first time to elucidate the hydrogeochemistry of groundwater and determine the suitability of water for drinking and other purposes. Hydrogeochemical investigations, which are significant for the assessment of water quality, have been done to study the source of dissolved ions in groundwater of Champhai valley, Mizoram, India. Based on the variations on the geomorphological and geological factors, the encountered data revealed that Ca+Mg are most predominant constituents followed by Na. An anion group HCO3 is more dominant than Cl & SO4. The Piper trilinear plot indicates dominant hydro geochemical facies of Ca-Mg- HCO3 type, and less dominance of Na-HCO3 & Ca-Mg-SO4-Cl types. The aqueous geochemistry of aquifer has been studied by adopting equilibrium thermodynamic approach. The solubility-equilibrium hypothesis suggests that groundwater is under saturated with respect to calcite, dolomite, aragonite as well as gypsum and anhydrite. The high concentration of calcium and magnesium with bicarbonate is related to dissolution of calcite, dolomite and others. The overall hydrochemistry suggests that waters are suitable for drinking and domestic purposes

Contamination and mobilization of arsenic in the soil and groundwater and its influence on the irrigated crops, Manipur Valley, India

The arsenic concentration in groundwater used for irrigating the rice crops varies from 10 to 475 ppb. The Disang shales, deposited under marine environment, appear to be the main source of arsenic contaminating the groundwater. The arsenic content in the rice roots vary from 32 to 52 ppm while the arsenic in the grains is far above the limit prescribed by WHO. Sequential extraction process results indicate that a large part of arsenic is present in the residual phases. High concentration of arsenic at root depth is present in crystalline Fe-oxides and is available for the rice plants. Sequential extraction experiment on soils indicate low arsenic content in organic matter compared to the above phases

Arsenic contamination in the groundwater of Thoubal and Bishnupur district of Manipur, India

Groundwater plays an important role in shaping the economic and social health of urban and rural population throughout the globe, however the distribution of good quality groundwater is quite uneven. In many parts of the world, especially in the South and South-East Asian nations, manifold higher concentrations of arsenic (As) than the WHO permissible limit has been reported. Still it seems that the extent of the As contamination is not known completely, as in the case of North-Eastern Indian states where very limited studies has been conducted till date. A systematic study has thus been undertaken to assess the groundwater quality of Thoubal and Bishnupur district of Manipur. In total 26 water samples have been collected and analyzed for various elements, including the arsenic. More than 45 % of collected water samples have shown As concentrations well above the permissible limit (10μg/L) prescribed by WHO for drinking water. The highest concentration of arsenic (535μg/L) has been reported from Ngangkha Lawai Mamang Leikai area of Bishnupur district which is fifty fold higher than the WHO limit and tenfold higher than the Indian permissible limit (50μg/L) of As in drinking water. The study indicates that these two districts are severely affected by as contamination in the groundwater

Geothermal energy resources of wadi Al-Lith, Saudi Arabia

The entire western Arabian shield is the domain of both hydrothermal and enhanced geothermal systems associated with volcanic centres (Harrats) and high heat generating granites. The most prominent sites of hydrothermal systems are located around Al-Lith and Jizan. The hydrothermal system in Al Lith is controlled by high heat generating (~11μW/m 3 ) post orogenic granites. The high heat flow value of >80mW/m 2 across Al-Lith coast is due to such granite intrusives, presence of dike swarms that intrude into the granites as well as position of Moho at shallow level. Although the thermal waters are chloride rich, Red Sea involvement is not observed. Long residence time and water rock interaction with granites are the main processes responsible for chloride enrichment in the thermal waters. Oxygen isotope shift indicates presence of high temperature geothermal system in the area. The tritium values indicate that the circulating waters are >75years old

Desalination of seawater using geothermal energy to meet future fresh water demand of Saudi Arabia

The future economy of the Middle East countries (GDP growth) depends on the availability of fresh water for domestic and agricultural sectors. Saudi Arabia, for example, consumes 275 L/day per capita of water that is generated from desalination process using 134 x 106 kWh of electricity. With 6 % population growth rate, demand for fresh water from fossil fuel based desalination plants will grow at an alarming rate. It has been reported that Saudi Arabia’s reliance on fossil fuels to generate electricity and generate fresh water through desalination using the same energy source is economically and politically unsustainable. This may lead to destabilisation of the global economy. However, Saudi Arabia has large geothermal resources along the Red Sea coast that can be developed to generate power and support the generation of fresh water through desalination. The cost of fresh water can be further lowered from the current US$ 0.03/m3. Among the gulf countries, Saudi Arabia can become the leader in controlling CO2 emissions and mitigating the impact on climate change and agricultural production. This will enable the country to meet the growing demand of food and energy for the future population for several decades and to reduce food imports. © 2016, Springer Science+Business Media Dordrecht

Understanding the evolution of thermal fluids along the western continental margin of India using geochemical and boron isotope signatures

Thermal springs lined up for about 350 km along the Western coast of Maharashtra, India, have been studied for major, minor, trace and rare earth elements, along with the boron isotope ratios for selected samples, to understand their evolution pattern. These alkaline springs have discharge temperatures varying from 40 to 72 degrees C. Based on the major ion composition, it is established that most of the thermal springs are of Na(Ca)-Cl or Ca(Na)Cl type, with a few of Na-Cl(SO4) type. Only one thermal spring at Rajapur is Na-HCO3 type behavior. Trace elements concentration vary significantly e.g., Li (19-386 ppb), B (104-1362 ppb), Sr (16-13560 ppb), Rb (13-220 ppb), Cs (0.75-44 ppb) and Ba (3-2077 ppb). Chondrite-normalized REE patterns indicate a pronounced 'Eu' anomaly probably due to the involvement of plagioclase, but the effect of temperature reaching more than 250 degrees C cannot be ruled out in case of some springs. First-time study of SHB isotope (range between 2.5 parts per thousand to 27.0 parts per thousand) of the West Coast thermal fluid suggests role of leaking marine sediments in their evolution. Water-rock interaction experiments with granite, basalt and diluted seawater at elevated temperatures and pressures have given an insight into the evolution of the thermal springs. Based on all the findings, a conceptual model has been prepared, which gives an overview of the evolution of the thermal springs

Origin and evolution of ‘intracratonic’ thermal fluids from central-western peninsular India

The chemical and isotopic composition of several thermal springs and associated gas phases in a large sector of central-western peninsular India has been investigated. Such springs have meteoric isotopic signature and emerge, after very well developed convective circulation at depth, along important tectonic structures such as the Son–Narmada–Tapti rift zone and the West Coast Fault. Chemical components in both gas and liquid phases and geothermometric estimations suggest that such springs are not related to the presence of any active hydrothermal systems at shallow depth in any of the studied areas. The hottest convective water emerges at Tattapani at near boiling point for water at atmospheric pressure (>90°C) in association with an N2-rich gas phase of clear meteoric signature. Since such fluids do not carry any corrosive components, they could be conveniently exploited for industrial purposes, such as drying processes. From a tectonic point of view, the presence of thermal emergences scattered in a wide area along geologically well defined structures, which also generate frequent moderate earthquakes, suggests that such structures are active. Although the isotopic composition of thermal springs points to a meteoric origin, their feeding aquifers are not topographically driven as in most active Alpine orogenic belts. The relative high quantity of total helium in the associated gas phase suggests also that they are really deep, old, long circulating waters. We propose for such waters the term ‘intracratonic thermal waters’ since the isotopic signature of He in the gas phase does not show any release of primordial 3He in any of the areas of spring emergence. Based on the quite low 3He/4He ratio in the gas phase we suggest also that, in spite of its morphological shape, the Narmada–Son–Tapti rift zone cutting the Indian subcontinent in two is more related to paleo-suture rather than to a mid-continental rift system© Elsevie

Understanding the evolution of thermal fluids along the western continental margin of India using geochemical and boron isotope signatures

Thermal springs lined up for about 350 km along the Western coast of Maharashtra, India, have been studied for major, minor, trace and rare earth elements, along with the boron isotope ratios for selected samples, to understand their evolution pattern. These alkaline springs have discharge temperatures varying from 40 to 72 °C. Based on the major ion composition, it is established that most of the thermal springs are of Na(Ca)-Cl or Ca(Na)-Cl type, with a few of Na-Cl(SO4) type. Only one thermal spring at Rajapur is Na-HCO3 type behavior. Trace elements concentration vary significantly e.g., Li (19–386 ppb), B (104–1362 ppb), Sr (16–13560 ppb), Rb (13–220 ppb), Cs (0.75–44 ppb) and Ba (3–2077 ppb). Chondrite-normalized REE patterns indicate a pronounced ‘Eu’ anomaly probably due to the involvement of plagioclase, but the effect of temperature reaching more than 250 °C cannot be ruled out in case of some springs. First-time study of δ11B isotope (range between 2.5‰ to 27.0‰) of the West Coast thermal fluid suggests role of leaking marine sediments in their evolution. Water-rock interaction experiments with granite, basalt and diluted seawater at elevated temperatures and pressures have given an insight into the evolution of the thermal springs. Based on all the findings, a conceptual model has been prepared, which gives an overview of the evolution of the thermal springs