Uranium In Groundwater Research Articles

Studies on hydrogeochemistry of uranium in groundwater of Tirunelveli district, Tamil Nadu, India

Studies on hydrogeochemistry of uranium in groundwater of Tirunelveli district, Tamil Nadu, India

Appraisal of age-dependent radiological risk caused by ingestion of uranium in groundwater of Patiala district, Punjab

Appraisal of age-dependent radiological risk caused by ingestion of uranium in groundwater of Patiala district, Punjab

Hydrogeochemical constraints on uranium contamination of groundwater for drinking water supplies and associated health risks

The groundwater quality of Punjab, India is of huge concern owing to the presence of various toxic contaminants that includes uranium and other trace elements. The focus of this study is to identify the hydrogeochemical processes responsible for uranium mobilization in groundwater and evaluation of groundwater quality in uranium contaminated zones for drinking, irrigation use along with associated health risks. The study was conducted using the water quality data obtained from 302 sampling locations covering the entire state of Punjab reported by Central Ground Water Board between 2019 and 2020. It was observed that around 50% of the samples were exceeding the drinking water acceptable limits for total alkalinity, magnesium, pH, and Total Dissolved Solids. Around 25% of the samples were above drinking water acceptable limit for uranium in groundwater. A comprehensive multiplicative water quality index (MED-WQI) well represented the consolidated perspective of all individual water quality parameters wherein 40 sampling locations in districts viz. Bathinda, Fazilka, Ferozepur, Jalandhar, Kapurthala, Ludhiana, Muktsar and Sangrur fall under heavily-polluted water quality class due to high levels of uranium, alkalinity, and hardness. The Piper plots and Gibbs diagram depicted that the majority of groundwater samples were characterized as Na+–HCO3−, Ca2+–Mg2+–HCO3− systems driven by rock-water interactions. Speciation analysis indicates that the dominant uranium species in groundwater of U-affected regions was primarily associated with calcium and alkalinity and exist in the form of CaUO2(CO3)32−, Ca2UO2(CO3)3(aq), UO2(CO3)34−, and UO2(OH)3−. Various irrigation indices depict that the groundwater in majority of the state, barring few districts in Malwa region, was suitable for irrigation. Further, a non-carcinogenic health risk assessment model showed association of high health risk with heavily-polluted water quality class. The results of this study would aid regulatory authorities in designing remedial strategies and frame policy actions toward groundwater quality improvement in the uranium-affected regions of Punjab.

Enhanced reduction of uranium (VI) in groundwater via regulation of heat-activated persulfate: The role of formate and its mechanisms

Hexavalent uranium (U(VI)) in groundwater may cause human health problems. Therefore, the effectively removal of U(VI) from groundwater has become a urgent issue. Advanced reduction processes based on persulfate (PS) have been used to reduce pollutants. However, low efficiency limited its application. In this study, the U(VI) reduction in groundwater by heat-activated persulfate was systematically examined in the presence of formate (FA). The results indicated that FA enhanced U(VI) reduction compared to heat-persulfate system. The U(VI) reduction efficiency reached 86% in the presence of 5 mg·L−1, 0.5 M persulfate and 0.3 M formate at acidic pH (4.6) and 70 °C within 60 min. Coexisting HCO3-, acetic acid and oxalic acid influenced U(VI) reduction, while NO3- and Cl- had no effect on U(VI) reduction by heat-persulfate-formate (H-PS-FA) process. According to the electron spin resonance experiment (ESR) results, CO2·- was verified to be largely responsible for U(VI) reduction in H-PS-FA system, meanwhile, S2O8·- and O2·- radicals also play a non-negligible role in reduction. More importantly, the test of U(VI) reduction in real groundwater validated that H-PS-FA system has significant potential and can be applied for reduction of U(VI) contaminated groundwater in uranium mining areas.

Uranium and lanthanum in Norwegian drinking water – Is there cause for concern?

Due to natural conditions such as geology, topography, and climate, and historical features such as resource utilization, land use, and settlement patterns, the drinking water supply in Norway is separated into many public and private water supply systems. This survey sheds light on whether the Drinking Water Regulation's limit values provide a sufficient basis for ensuring safe drinking water for the Norwegian population. Participating waterworks, both private and public, were spread throughout the country, in 21 municipalities with different geological conditions. The median value for the number of persons supplied by the participating waterworks was 155. The two largest waterworks, both of which supply >10,000 people, have water sources from unconsolidated surficial sediments of latest Quaternary age. Fourteen waterworks have water sources from bedrock aquifers. Raw and treated water were analysed for 64 elements and selected anions. The concentration of manganese, iron, arsenic, aluminium, uranium, and fluoride exceeded the respective drinking water regulations' parametric value given in Directive (EU) 2020/2184. Regarding the rare earth elements, neither WHO, EU, USA nor Canada have established any limit values. However, concentration of lanthanum in groundwater from a sedimentary well exceeded the health-based guideline value that applies in Australia. Results from this study raise the question of whether increased precipitation can have an impact on the mobility and concentration of uranium in groundwater from bedrock aquifers. Furthermore, findings of high levels of lanthanum in groundwater create uncertainty as to whether the current quality control of Norwegian drinking water is sufficient.

δ18O and δ2H isotopes, trace metals and major ions in groundwater around uranium and fluoride contaminated Indus valley Quaternary alluvial plain, SW Punjab, India: Implications on hydrogeochemical processes, irrigation use and source

Uranium and fluoride enrichment in groundwater along alluvial plains pose a severe threat to living beings like cancer, fluorosis and crop yield as witnessed around semi-arid southwest Punjab, India. In-situ groundwater was examined for major ions, stable isotopes and trace metals to understand the hydrogeochemical processes, contaminant origin and health risks around SW Punjab, India. Groundwater from a freshly drilled bore well is found to be hard, alkaline, and saline with total dissolved solids and salinity up to 1300 and 1500 mg L−1, respectively. Fluoride (up to 4 mg L−1) and uranium (up to 90.07 μg L−1) contents exceed permissible limits in most samples and originated from fertilizer inputs and aquifer leaching. Uranium contents decline with depth, while fluoride remains invariable. Decreased U contents are inferred to be caused by U(VI) reduction to U(IV) as evidenced by an increase in Fe2+ vs. Fe3+, S2− vs. S6+ and N3− vs. N5+ with depth. NaHCO3, NaCl + NaHCO3 and NaCl are the dominant water types for shallow (<38 m), intermediate (49–83 m) and deeper groundwater (105–128 m) with Na+ and HCO3− as the dominant cations and anions, respectively. Silicate weathering majorly controlled the groundwater geochemistry together with a partial contribution from cation exchange processes. Unsuitability for drinking and irrigation use is envisaged for all depths, while deeper groundwater is safe in regard to radiological risk. δ18O and δD variations are suggestive of evaporation dominance in shallow groundwater, while intermediate groundwater witness canal and groundwater mixing and deeper groundwater are recharged through higher altitude.

Geo-Environmental Models of In-Situ Leaching Sandstone-Type Uranium Deposits in North China: A Review and Perspective

Since the 1990s, sandstone-type uranium in the northern basin of China has become the main target for mining. Uranium mining can cause a series of impacts on the environment. A conceptual model of the geo-environment for sandstone-type uranium in northern China was described, which covers the changes in the geo-environmental characteristics in the natural state, in the mining process, during decommissioning and after treatment. Sandstone-type uranium is mainly distributed in the Songliao, Erlian, Ordos, Turpan–Hami and Ili Basins, which have arid climates and poor stratum permeability. Pitchblende is the main uranium-bearing mineral and is associated with iron, copper, coal, organic matter and other minerals. The mineral often has a low ore grade (0.01–1.0%) and high carbonate content (2–25%). Uranyl carbonate accounts for more than 90% of the total uranium in groundwater. The uranyl content is closely related to the TDS. The TDS of groundwater in the eastern and central ore belts is usually lower than 2 g/L, while in the western region, such as Xinjiang, it can exceed 10 g/L. In situ leaching (ISL) is the main mining method that results in groundwater pollution. Acid leaching leads to a pH decrease (&lt;3), and heavy metals represented by U and Fe exceed the background values by hundreds of times, resulting in groundwater pollution. CO2 leaching is more environmentally friendly, and the excess ions are usually Ca2+, Mg2+, NO3− and HCO3−. Soil chemical anomalies originate mostly from wind erosion and precipitation leaching of decommissioned tailings. Uranium pollution is mainly concentrated within 20 cm of the surface, and the exceedance generally varies from two to 40 times. During ISL, a series of environmental measures will be taken to prevent pollution from being exposed to the surface. After treatment, the decommissioned uranium mines will likely have no impact on the surrounding environment. In the future, the protection of groundwater should be strengthened during production, and remediation methods based on electrokinetic, microbial and permeable reactive barrier (PRB) technology should be further researched.

Concurrent reductive decontamination of chromium (VI) and uranium (VI) in groundwater by Fe(0)-based autotrophic bioprocess

The co-presence of chromium (VI) [Cr(VI)] and uranium (VI) [U(VI)] is widely found in groundwater, imposing severe risks on human health. Although zerovalent iron [Fe(0)] supports superb performance for bioreduction of Cr(VI) and U(VI) individually, the biogeochemical process involving their concurrent removal with Fe(0) as electron donor remains unexplored. In the 6-d batch study, 86.1% ± 0.7% of Cr(VI) was preferentially eliminated, while 78.4% ± 0.5% of U(VI) removal was achieved simultaneously. Efficient removal of Cr(VI) (100%) and U(VI) (51.2% ∼ 100%) was also obtained in a continuous 160-d column experiment. As a result, Cr(VI) and U(VI) were reduced to less mobile Cr(III) and insoluble U(IV), respectively. 16 S rRNA sequencing was performed to investigate the dynamics of microbial community. Delftia, Acinetobacter, Pseudomonas and Desulfomicrobium were the major contributors mediating the bioreduction process. The initial Cr(VI) and hydraulic retention time (HRT) incurred pronounced effects on community diversity, which in turn altered the reactor’s performance. The enrichment of Cr(VI) resistance (chrA), U(VI) reduction (dsrA) and Fe(II) oxidation (mtrA) genes were observed by reverse transcription qPCR. Cytochrome c, glutathione and NADH as well as VFAs and gas metabolites also involved in the bioprocess. This study demonstrated a promising approach for removing the combined contaminants of Cr(VI) and U(VI) in groundwater.

Nitrate-Stimulated Release of Naturally Occurring Sedimentary Uranium.

Groundwater uranium (U) concentrations have been measured above the U.S. EPA maximum contaminant level (30 μg/L) in many U.S. aquifers, including in areas not associated with anthropogenic contamination by milling or mining. In addition to carbonate, nitrate has been correlated to uranium groundwater concentrations in two major U.S. aquifers. However, to date, direct evidence that nitrate mobilizes naturally occurring U from aquifer sediments has not been presented. Here, we demonstrate that the influx of high-nitrate porewater through High Plains alluvial aquifer silt sediments bearing naturally occurring U(IV) can stimulate a nitrate-reducing microbial community capable of catalyzing the oxidation and mobilization of U into the porewater. Microbial reduction of nitrate yielded nitrite, a reactive intermediate, which was further demonstrated to abiotically mobilize U from the reduced alluvial aquifer sediments. These results indicate that microbial activity, specifically nitrate reduction to nitrite, is one mechanism driving U mobilization from aquifer sediments in addition to previously described bicarbonate-driven desorption from mineral surfaces, such as Fe(III) oxides.

Characteristics of groundwater microbial communities and the correlation with the environmental factors in a decommissioned acid in-situ uranium mine.

Microorganisms play an important role in the bioremediation process for the decommissioned acid in-situ leaching uranium mine. It is crucial to understand the original microbial community characteristics before the in-situ bioremediation. However, there are limited studies on the groundwater microbial characteristics in the decommissioned acid in-situ uranium mine. To this end, we collected groundwater samples, including the groundwater that originally residual in the borehole (RW) and the aquifer water (AW), from a decommissioned acid in-situ uranium mine in the southern margin of Ili Basin in Xinjiang, China. The occurrence characteristics of the groundwater microbial communities and their correlation with environmental factors were systematically studied based on the high throughput 16S rRNA gene sequencing data and geochemical data. Results found that the AW samples had higher alpha- and beta- diversity than the RW samples. The relative abundance of Sporosarcina, Sulfobacillus, Pedobacter and Pseudomonas were significantly different in the AW and RW samples, which had significant correlation with pH, metals, and sulfate, etc. A series of reducing microorganisms were discovered, such as sulfate reduction (e.g., Desulfosporosinus) and metal reduction (e.g., Arthrobacter, Bacillus, Clostridium, Pseudomonas, and Rhodanobacter), which have the potential to attenuate sulfate and uranium in groundwater. In addition, we found that pH and redox potential (Eh) were the dominant environmental factors affecting the microbial composition. This study extends our knowledge of microbial community structure changes in the decommissioned acid in-situ uranium mine and has positive implications for assessing the potential of natural attenuation and bioremediation strategies.

Natural radioactivity due to uranium and radon in thermal groundwaters of Central Brazil

Natural radioactivity due to uranium and radon in thermal groundwaters of Central Brazil

Assessing the Baseline Uranium in Groundwater around a Proposed Uraninite Mine and Identification of a Nearby New Reserve

The presence of uranium in groundwater is a cause of concern all over the world. In mineralized regions where elevated concentrations of uranium are possible in groundwater, mining activities can further degrade the water quality. Hence, it is essential to document the baseline uranium concentration in groundwater before the commencement of mining. This study was carried out with the objective of assessing the concentration of uranium in groundwater around a proposed uraninite mining site in the Gogi region, Karnataka, India. Gogi is a village in the Yadgir district of Karnataka where groundwater is the main source of water for domestic needs. The uranium mineralized zone in this region occurs along the major E-W trending Gogi-Kurlagere fault at a depth of about 150 m. Groundwater samples were collected every three months from January 2020 to October 2020 from 52 wells located in this area. The concentration of uranium in groundwater ranged from 1.5 ppb to 267 ppb. The USEPA and WHO have recommended a permissible limit of 30 ppb, while the Atomic Energy Regulatory Board of India has a limit of 60 ppb for the purpose of drinking water. Based on these permissible limits for uranium in drinking water, concentrations exceeded the limit in about 25% of wells within 20 km from the mineralized region. Wells present in the granitic and limestone terrain exhibited higher concentrations of uranium in this area. Uranium concentration in groundwater changes depending on the degree of weathering, lithology, and rainfall recharge. This study will serve as a baseline and will help to assess the impact of mining activities in this region in the future. In wells where the uranium concentration exceeds permissible limits, it is suggested not to use groundwater directly for drinking purposes. These sites need to be explored further for the possible presence of uranium-bearing minerals.

The study of uranium in groundwater and consequent ingestion dose in marginal alluvial plains of Bihar based on Empirical Bayesian Kriging method

The study of uranium in groundwater and consequent ingestion dose in marginal alluvial plains of Bihar based on Empirical Bayesian Kriging method

Determination of Uranium Concentrations and 234U/238U Isotopic Ratios in Plants and the Groundwater Used in Their Cultivation in an Area with High Background Radiation

The weathering of rocks and soil causes uranium to collect in groundwater. In this article, we attempted to assess the activity concentrations of uranium and 234U/238U isotopic ratios in various groundwater samples and plants obtained from the Ha’il region, Saudi Arabia. The results showed that the concentrations of 238U ranged between 0.08 ± 0.04 and 1.11 ± 0.06 Bq L−1, with an average of 0.67 ± 0.05 Bq L−1. Activity concentrations of 234U ranged between 0.12 ± 0.01 and 2.2 ± 0.8 Bq L−1, with an average of 1.26 ± 0.11 Bq L−1. The international permissible limit of uranium in groundwater is 0.372 Bq L−1. The 234U/238U activity ratios in the collected groundwater samples ranged between 1.5 ± 0.09 and 2.49 ± 1.27 Bq L−1, with an average of 1.95 ± 0.52 Bq L−1. In fruit-bearing trees, the 234U/238U activity ratios were 1.57 ± 0.84, 2.58 ± 1.01, and 2.69 ± 0.95 Bq L−1 for lemon, fig, and narenj. In fruit-bearing shrubs, the 234U/238U activity ratios were 2.37± 0.69 and 2.68 ± 0.69 Bq L−1 for green pepper and eggplant. Our goal is to increase the understanding of the factors that govern uranium’s activity and isotopic composition to better understand its prospective utilization as a tracer in groundwater chemistry and hydrology, as well as the possibility of exploiting this area for irrigation. In this investigation area, the groundwater and plants were unfit for human consumption.

Modelling of the geochemical behaviour of uranium in groundwater of the Metropolitan Region of Recife, Brazil

ABSTRACT Groundwater supplied by Beberibe aquifer, the main source for the metropolitan region north of Recife, Brazil, exhibits radioactivity because of the presence of uranium resulting from the alteration of phosphate rocks that occur at the base of the Gramame formation, which is superimposed on the aquifer. Using geochemical modelling as a tool to characterise hydrodynamic systems, studies were performed assessing uranyl ions and their interaction with other chemical and mineralogical species found in the aquifer. The results of the geochemical modelling made it possible to perform studies of uranium mobility in the aquifer, analysing the alteration of phosphate minerals and revealing the occurrence of different chemical species. This model suggests that the species present in the aquifer were available for the trophic chain and capable of affecting human health in a differentiated way.

Assessment of Age-Dependent Radiation Dose and Toxicological Risk of Uranium in Ground Water around Uranium Mines in Sikar, Rajasthan

Assessment of Age-Dependent Radiation Dose and Toxicological Risk of Uranium in Ground Water around Uranium Mines in Sikar, Rajasthan

Analysis of Natural Uranium in Groundwater of Jhajjar District of Haryana, India using LED Fluorimeter

Analysis of Natural Uranium in Groundwater of Jhajjar District of Haryana, India using LED Fluorimeter

Concentration mechanism of fluorine, arsenic, and uranium in groundwater of the Hailar Basin, China

Located in a semiarid region of the Hulun Buir League in China’s Inner Mongolia Autonomous Region, the Hailar Basin is a region with less precipitation, where groundwater is the most important water supply source. It is important to study groundwater characteristics and hydrogeochemical processes for the better management of groundwater resources. Fluorine (F), arsenic (As), and uranium (U) cocontamination currently exists in the groundwater of the Hailar Basin, China. To understand the concentration mechanism of F, As, and U in groundwater in the study area, groundwater samples were collected for detection and analysis. The results showed that the main hydrochemical types in the study area were Cl–Na, HCO3–Na, and HCO3–Ca. The median values of F, As, and U were 3.32 mg/L, 0.029 mg/L, and 0.066 mg/L, respectively, which all exceeded the World Health Organization (WHO) guidelines. Through a Gibbs diagram and endmember diagram, it can be seen that the groundwater in the study area is mainly affected by the hydrogeochemical effects of evaporative crystallization, rock weathering mechanisms, and the dissolution of silicate rock and evaporative salt rock minerals. Mineral dissolution, cation exchange, and weakly alkaline environments are important factors affecting F concentrations. Low NO3− and SO42− concentrations cause a reducing environment, and the competitive adsorption of HCO3− promotes As pollution. The concentrations of Ca2+, Mg2+, SO42−, and NO3− have a great influence on the concentration of U.

Evaluation of uranium contamination of Raipur district of Chhattisgarh: GIS assisted hydrogeochemical study of underground water

This study analyzed uranium contamination in groundwater samples from the Raipur district of Chhattisgarh (India), its mobilization with complexing anions, and its effect on the overall water quality index of the studied area. Seventy-three groundwater samples were taken during the pre- and post-monsoon seasons in May and September respectively. All of the collected samples were analyzed for uranium and associated water quality factors. Analytical data such as pH, ORP, electrical conductivity, total dissolved solids, salinity, alkalinity, total hardness, calcium hardness, magnesium hardness, sulphate, nitrate, bicarbonate, chloride, and fluoride were analyzed using descriptive statistics, correlation, factor, and hierarchical agglomerative cluster analysis. The groundwater quality of the research area has been evaluated by calculating the water quality index of sampled water. It was discovered that uranium and chloride had a weak relationship prior to the monsoons and a strong relationship afterwards. Chloride may therefore play a crucial role in the mobilization of uranium. ArcGIS 10.3 with IDW interpolation was used for uranium concentration and water quality index (WQI) presentation. It was found that the sequential increase of uranium in groundwater by geogenic processes may be the root cause of water quality index degradation in the research area.

Geogenic controls on the high levels of uranium in alluvial aquifers of the Ganga Basin

The Indo-Gangetic Basin (IGB) alluvial aquifer system provides a reliable drinking water supply to over half a billion people. Understanding the groundwater quality, aquifer processes, groundwater storage, and depletion trends in the IGB alluvial aquifer system— one of the world's most important freshwater resources has been the focus of many previous studies. However, understanding what governs uranium variability in the IGB alluvial aquifer system— for example, whether uranium is released from natural deposits or anthropogenic sources such as mill tailing, emissions from the nuclear industry, combustion of fossil fuels, and phosphate fertilizers— are under-explored but critically important for constraining the environmental fate of uranium. Here, we present surface and groundwater uranium concentration data in the central parts of the IGB alluvial aquifer system. We find a high concentration of groundwater uranium above the World Health Organization provisional guideline value of 30 μg/L in 17% (n = 29) of collected groundwater samples, whereas other heavy metals, namely Cr, Ni, Pb, and Cd were within the recommended range. Trace element systematic demonstrates that anomalous uranium enrichment is primarily derived from geogenic sources, while uranium mobility is predominantly controlled by the alkalinity (a proxy for bicarbonate), hence by soluble uranyl carbonate complexes. As in the year 2020, the Bureau of Indian Standard incorporated uranium as a possible drinking water contaminant, our dataset calls for additional assessments of groundwater uranium concentrations in Indian groundwater resources because uranium concentration data are scarce compared to other geogenic contaminants such as arsenic and fluoride. We conclude that uranium, like arsenic and fluoride, is also critical geogenic contaminant in the alluvial aquifers that needs to be better monitored as higher levels of uranium in drinking water have adverse health effects.