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

Abstract

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.

Potential interplay of Uranium with geochemical variables and mineral saturation states in groundwater

“…Leachate may occur in POM. This is observed from the piper plot by the formation of the mixed type of cations and anions Ca-Na-HCO 3 are distinctive of granite aquifer with feldspars (Cho and Choo 2019) and also Ca-Cl (Chidambaram et al 2012).…”

“…The solubility of radionuclides governs the distribution and dispersion in water (Jordana and Batista 2004). Studies have reported U level in groundwater used for drinking purpose (De Camargo and Mazzilli 1996;Chau and Michalec, 2009;Killiari and Pashalidis 2010;Thivya et al 2015aThivya et al , 2015bBrindha et al 2011a, b;Cho and Choo 2019). The studies have also tried to trace the geochemical processes behind the release of U in groundwater (Mahalakshmi et al 2017, Paramaguru et al 2016Chandramohan et al 2018;Adithya et al 2019Adithya et al , 2020Selvi et al 2016).…”

Statistical Analysis and Thermodynamic Equilibrium Modelling for Chemical Composition of Groundwater and Spring Water at Jeju Island, South Korea

“…The statistical method such as multivariate analysis can be used to characterize its geochemical processes through data reduction and classification with respect to chemical composition of groundwater. When correlation analysis and factor analysis are applied to chemical data of groundwater, dominant processes can be identified as common factors that are sets of variables having strong associations with one another [33][34][35][36][37].…”

Comparison of Uranium Isotopes and Classical Geochemical Tracers in Karst Aquifer of Ljubljanica River catchment (Slovenia)

“…The use of the U isotopic composition has been proven to be very valuable for studying different physicochemical processes in estuarine water [8], seawater [9,10], and continental surface water and groundwater [11][12][13][14]. U isotopes in continental waters can be investigated as a tracing or dating tool for a broad spectrum of hydrological and geological processes [15,16].…”

“…However, not much is known about freshwater draining areas with a predominantly carbonate lithology. In such hydrogeological settings, these isotopes have much lower concentrations of 0.02-21.4 µg/L (mean: 0.3 µg/L) [12,13,34], which is analytically challenging. Recently, multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has been used to improve precision because it affords high absolute sensitivity and simultaneous detection of ions compared with quadrupole-based ICP-MS and achieves a higher sample throughput compared with thermal ionization mass spectrometry (TIMS).…”