Occurrence of the radionuclides in groundwater of crystalline hard rock regions of central Tamil Nadu, India

Thivya, C.; Chidambaram, S.; Tirumalesh, K.; Prasanna, Mohan Viswanathan; Thilagavathi, R.; Nepolian, M.

doi:10.1007/s10967-014-3630-z

Cited by 23 publications

(4 citation statements)

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“…Radon, which has a half-life of 3.8 days, is an inert, radioactive gas that basically originates from the decay of radium. Many studies have reported higher uranium and radon concentrations in groundwater in granitic terrains [3][4][5][6][7][8][9][10]. Higher radon concentrations are commonly detected in areas underlain by granites that usually contain more uranium than other rock types [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Geochemical Behavior of Uranium and Radon in Groundwater of Jurassic Granite Area, Icheon, Middle Korea

Cho

Choo

2019

Water

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Uranium concentrations (a total of 82 samples) in groundwater in Icheon, middle Korea, showed a wide range from 0.02 to 1640 μg/L with a mean of 56.77 μg/L, a median of 3.03 μg/L, and a standard deviation of 228.63 μg/L. Most groundwater samples had quite low concentrations: 32.9% were below 1 μg/L, while 15.9% exceeded 30 μg/L, the maximum contaminant level (MCL) of the US EPA (Environmental Protection Agency). Radon concentrations also ranged widely from 1.48 to 865.8 Bq/L. Although the standard deviation of radon was large (151.8 Bq/L), the mean was 211.29 Bq/L and the median was 176.86 Bq/L. Overall, 64.6% of the samples exceeded the alternative maximum contaminant level (AMCL) of the US EPA (148 Bq/L). According to statistical analyses, there was no close correlations between uranium and radon, but there were correlations between uranium and redox potential (Eh) (−0.54), dissolved oxygen (DO) (−0.50), HCO3− (0.45), Sr (0.65), and SiO2 (−0.44). Radon showed independent behavior with respect to most components in groundwater. Uranium concentrations in groundwater increased with increasing water–rock interactions. Anomalously high uranium and radon concentrations in groundwater are preferentially localized in granite areas and spatial distributions are remarkably heterogeneous.

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Section: Introductionmentioning

confidence: 99%

Geochemical Behavior of Uranium and Radon in Groundwater of Jurassic Granite Area, Icheon, Middle Korea

Cho

Choo

2019

Water

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“…The study area, Madurai district, is also one such complex hard-rock terrain of graphitebearing hornblende gneiss and calc-granulites. It is reported that these rock types contain higher amounts of U, in the range of 12-28 mg l -1 (Pandey and Krishnamurthy 1995;Thivya et al 2014). Though there were reports of U in the rock matrix, groundwater U data are still unavailable and no studies have been attempted so far to estimate the dissolved U and factor controlling its concentration in this region.…”

Section: Introductionmentioning

confidence: 99%

Lithological and hydrochemical controls on distribution and speciation of uranium in groundwaters of hard-rock granitic aquifers of Madurai District, Tamil Nadu (India)

Thivya

Chidambaram

Keesari

et al. 2015

Environ Geochem Health

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Uranium is a radioactive element normally present in hexavalent form as U(VI) in solution and elevated levels in drinking water cause health hazards. Representative groundwater samples were collected from different litho-units in this region and were analyzed for total U and major and minor ions. Results indicate that the highest U concentration (113 µg l(-1)) was found in granitic terrains of this region and about 10 % of the samples exceed the permissible limit for drinking water. Among different species of U in aqueous media, carbonate complexes [UO2(CO3)(2)(2-)] are found to be dominant. Groundwater with higher U has higher pCO2 values, indicating weathering by bicarbonate ions resulting in preferential mobilization of U in groundwater. The major minerals uraninite and coffinite were found to be supersaturated and are likely to control the distribution of U in the study area. Nature of U in groundwater, the effects of lithology on hydrochemistry and factors controlling its distribution in hard rock aquifers of Madurai district are highlighted in this paper.

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“…Most of the studied aquifers within the southern states were reported to be hard-rock aquifers in the proximity of granitic rocks ,,,− and/or U mineralization zones, ,,, which likely impact the U contamination in these aquifers. However, in northwestern regions where U contamination is more prevalent, the literature is divided on the influence of basement granites.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Potential Drivers of Elevated Uranium Prevalence in Indian Groundwaters with a Unified Speciation Model

Sujathan

Singh

2023

Environ. Sci. Technol.

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Elevated uranium (U) (>WHO limit of 30 μg L −1 ) in Indian groundwaters is primarily considered geogenic, but the specific mineralogical sources and mechanisms for U mobilization are poorly understood. In this contribution, statistical and geochemical analyses of well-constrained metadata of Indian groundwater quality (n = 342 of 8543) were performed to identify key parameters and processes that influence U concentrations. For geochemical predictions, a unified speciation model was developed from a carefully compiled and updated thermodynamic database of inorganic, organic (Stockholm Humic model), and surface complexation reactions and associated constants. Critical U contamination was found at shallow depths (<100 m) within the Indo-Gangetic plain, as determined by bivariate nonparametric Kendall's Tau b and probability-based association tests. Analysis of aquifer redox states, multivariate hierarchical clusters, and principal components indicated that U contamination was predominant not just in oxic but mixed (oxic−anoxic) aquifers under high Fe, Mn, and SO 4 concentrations, presumably due to U release from dissolution of Fe/Mn oxides or Fe sulfides and silicate weathering. Most groundwaters were undersaturated with respect to relevant U-bearing solids despite being supersaturated with respect to atmospheric CO 2 (average pCO 2 of reported dissolved inorganic carbonate (DIC) data = 10 −1.57 atm). Yet, dissolved U did not appear to be mass limited, as predicted solubilities from reported sediment concentrations of U were ∼3 orders of magnitude higher. Integration of surface complexation models of U on typical aquifer adsorbents, ferrihydrite, goethite, and manganese dioxide, was necessary to explain dissolved U concentrations. Uranium contamination probabilities with increasing dissolved Ca and Mn exhibited minima at equilibrium solubilities of calcite [∼50 mg L −1 ] and rhodochrosite [∼0.14 mg L −1 ], respectively, at an average groundwater pH of ∼7.5. A potential indirect control of such U-free carbonate solids on U mobilization was suggested. For locations (n = 37) where dissolved organic carbon was also reported, organic complexes of U contributed negligibly to dominant U speciation at the groundwater pH. Overall, the unified model suggested competitive dissolution−precipitation and adsorption−desorption controls on U speciation. The model provides a quantitative framework that can be extended to understand dominant mobilization mechanisms of geogenic U in aquifers worldwide after suitable modifications to the relevant aquifer parameters.

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Occurrence of the radionuclides in groundwater of crystalline hard rock regions of central Tamil Nadu, India

Cited by 23 publications

References 21 publications

Geochemical Behavior of Uranium and Radon in Groundwater of Jurassic Granite Area, Icheon, Middle Korea

Geochemical Behavior of Uranium and Radon in Groundwater of Jurassic Granite Area, Icheon, Middle Korea

Lithological and hydrochemical controls on distribution and speciation of uranium in groundwaters of hard-rock granitic aquifers of Madurai District, Tamil Nadu (India)

Investigation of Potential Drivers of Elevated Uranium Prevalence in Indian Groundwaters with a Unified Speciation Model

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