Linkage-Mixed Covalent Organic Frameworks Synthesized by a Liquid-Solid Two-Phase Strategy for Photoenhanced Uranium Extraction.

Synthesizing COFs with hybrid linkage coupling with both reversible and irreversible natures remains a challenging issue. Herein, we report the synthesis of two rare COFs constructed by both reversible and irreversible linkages through a liquid-solid two-phase strategy. A systematic study reveals a one-pot, two-step reaction mechanism for the two COFs, the first step being a reversible Schiff base reaction and the second step being an irreversible Knoevenagel reaction. Interestingly, this hybrid linkage COF is found to show an outstanding photoenhanced uranium extraction performance. The results not only provide a general and green approach to develop the linkage chemistry of COFs but also enrich the synthesis toolboxes and application of COFs.

From caged compounds with isolated U atoms to frustrated magnets with 2- or 3-atom clusters: a review of Al-rich uranium aluminides with transition metals.

Crystal structures and physical properties of four families of Al-rich ternary uranium compounds with transition metals (TE) are reviewed, namely UTE2Al20, UTE2Al10, U6TE4Al43, and U3TE4Al12. The compounds can be described as consisting of 1 (isolated), 2 (dumbbells) or 3 (triangles) uranium atom clusters, surrounded (1-2-20, 1-2-10 and 6-4-43) or not (3-4-12) by large cages, which strongly influence their magnetic and related properties. Indeed, the ground states of the described systems evolve from Curie-like paramagnetism in the case of the phases with well-isolated, single U-atoms, to complex magnetic order or possible frustrated magnetism in the case of the systems with uranium triangles forming a breathing kagome lattice. We argue that the four families of uranium aluminides described in this review provide a unique opportunity to study magnetic interactions between U magnetic moments while gradually increasing the number of their nearest magnetic neighbors, and may also be helpful in understanding the fundamental origin of magnetic freezing phenomena.

Chemical bonding in Uranium-based materials: A local vibrational mode case study of Cs 2 UO 2 Cl 4 and UCl 4 crystals.

The Local Vibrational Mode Analysis, initially applied to diverse molecular systems, was extended to periodic systems in 2019. This work introduces an enhanced version of the LModeA software, specifically designed for the comprehensive analysis of two and three-dimensional periodic structures. Notably, a novel interface with the Crystal package was established, enabling a seamless transition from molecules to periodic systems using a unified methodology. Two distinct sets of uranium-based systems were investigated: (i) the evolution of the Uranyl ion (UO 2 2 + ) traced from its molecular configurations to the solid state, exemplified by Cs 2 UO 2 Cl 4 and (ii) Uranium tetrachloride (UCl 4 ) in both its molecular and crystalline forms. The primary focus was on exploring the impact of crystal packing on key properties, including IR and Raman spectra, structural parameters, and an in-depth assessment of bond strength utilizing local mode perspectives. This work not only demonstrates the adaptability and versatility of LModeA for periodic systems but also highlights its potential for gaining insights into complex materials and aiding in the design of new materials through fine-tuning.

Hydrogen-Bonded Cocrystals Encapsulating CsPbBr3 Perovskite Nanocrystals with Enhancement of Charge Transport for Photocatalytic Reduction of Uranium.

At present, poor stability and carrier transfer efficiency are the main problems that limit the development of perovskite-based photoelectric technologies. In this work, hydrogen-bonded cocrystal-coated perovskite composite (PeNCs@NHS-M) is easily obtained by inducing rapid crystallization of melamine (M) and N-hydroxysuccinimide (NHS) with PeNCs as the nuclei. The outer NHS-M cocrystal passivates the undercoordinated lead atoms by forming covalent bonds, thereby greatly reducing the trap density while maintaining good structure stability for perovskite nanocrystals. Moreover, benefiting from the interfacial covalent band linkage and long-range ordered structures of cocrystals, the charge transfer efficiency is effectively enhanced and PeNCs@NHS-M displays superior photoelectric performance. Based on the excellent photoelectric performance and abundant active sites of PeNCs@NHS-M, photocatalytic reduction of uranium is realized. PeNCs@NHS-M exhibits U(VI) reduction removal capability of up to 810.1 mg g-1 in the presence of light. The strategy of cocrystals trapping perovskite nanocrystals provides a simple synthesis method for composites and opens up a new idea for simultaneously improving the stability and photovoltaic performance of perovskite.

Hierarchical Porous Amidoximated Metal-Organic Framework for Highly Efficient Uranium Extraction.

With the rapid development of industry and technology, high-efficiency extraction of uranium from seawater is a research hotspot from the aspect of nuclear energy development. Herein, a new amidoximated metal-organic framework (UiO-66-DAMN-AO) constructed through a novel organic ligand of 2-diaminomaleonitrile-terephthalic acid (BDC-DAMN) is designed via one-step post-synthetic methods (PSM), which possess the merit of abundant multiaffinity sites, large specific surface area, and unique porous structure for efficient uranium extraction. Adopting one-step PSM can alleviate the destruction of structural stability and the reduction of the conversion rate of amidoxime groups. Meanwhile, introducing the BDC-DAMN ligand with abundant multiaffinity sites endow UiO-66-DAMN-AO with excellent adsorption ability (Qm = 426.3 mg g-1) and selectivity. Interestingly, the UiO-66-DAMN-AO has both micropores and mesopores, which may be attributed to the partial etching of UiO-66-DAMN-AO during the amidoximation. The presence of mesopores improves the mass transfer rate of UiO-66-DAMN-AO and provides more exposed active sites, favoring the adsorption of uranium on UiO-66-DAMN-AO. Thus, this study provides a feasible strategy for modifying metal-organic framework (MOFs) with plentiful amidoxime groups and the promising prospect for MOF-based materials to adsorb uranium from ocean.

Synthesis of Carboxyl-Functionalized COFs with Alternate Stable ß-Ketoenamine and Benzimidazole Linkages: Unraveling Exceptional Solvent Effects for Efficient Uranium Separation.

The prevalent π-π interactions in 2D covalent organic frameworks (COFs) impart a certain flexibility to the structures, making the stacking of COF layers susceptible to external stimuli and introducing some structural disorder. Recent research indicates that the flexibility between COF layers and the associated disorder significantly influence their selective adsorption performance toward gas molecules. However, the adsorption process in a solution environment is more complex compared to gas-phase adsorption, involving interactions between adsorbents and adsorbates, as well as the solvation effects of flexible 2D COFs. Therefore, the inherent flexibility and disorder in 2D COFs under solution conditions and their impact on the adsorption performance of metal ions have not been observed yet. Herein, the synthesis of a novel carboxyl-functionalized COF featuring stable ß-ketoenamine and benzimidazole linkages, named DMTP-COOH, is presented. DMTP-COOH exhibits excellent selective adsorption capability for uranium, with significantly different adsorption capacities observed after treatment with different solvents. This notable difference in adsorption capacity is observed under varying pH, concentration, time, and even in the presence of multiple competing ions. This work represents the first observation of the significant impact of solvent soaking treatment on the selective adsorption performance of COFs for uranium under liquid conditions.

Nanotrap Grafted Anionic MOF for Superior Uranium Extraction from Seawater.

On-demand uranium extraction from seawater (UES) can mitigate growing sustainable energy needs, while high salinity and low concentration hinder its recovery. A novel anionic metal-organic framework (iMOF-1A) is demonstrated adorned with rare Lewis basic pyrazinic sites as uranyl-specific nanotrap serving as robust ion exchange material for selective uranium extraction, rendering its intrinsic ionic characteristics to minimize leaching. Ionic adsorbents sequestrate 99.8% of the uranium in 120 mins (from 20,000 ppb to 24 ppb) and adsorb large amounts of 1336.8 mg g-1 and 625.6 mg g-1 from uranium-spiked deionized water and artificial seawater, respectively, with high distribution coefficient, Kd U ≥ 0.97 × 106  mL g-1 . The material offers a very high enrichment index of ≈5754 and it achieves the UES standard of 6.0 mg g-1 in 16 days, and harvests 9.42 mg g-1 in 30 days from natural seawater. Isothermal titration calorimetry (ITC) studies quantify thermodynamic parameters, previously uncharted in uranium sorption experiments. Infrared nearfield nanospectroscopy (nano-FTIR) and tip-force microscopy (TFM) enable chemical and mechanical elucidation of host-guest interaction at atomic level in sub-micron crystals revealing extant capture events throughout the crystal rather than surface solely. Comprehensive experimentally guided computational studies reveal ultrahigh-selectivity for uranium from seawater, marking mechanistic insight.

Realizing Direct Uranium Extraction from Seawater Using a Carboxyl-g-C3N4/CdS Hydrogel.

The photocatalytic U(VI) reduction is regarded as an effective strategy for recovering uranium. However, its application in seawater uranium extraction poses challenges due to limited reactivity in the presence of carbonate and under atmospheric conditions. In the present study, a photoactive hydrogel made of carboxyl-functionalized g-C3N4/CdS (CCN/CdS) is designed for extracting uranium. The carboxyl groups on g-C3N4 enhance the affinity toward uranyl ions while CdS facilitates the activation of dissolved oxygen. Under atmospheric conditions, the prepared hydrogel catalyst achieves over 80% reduction rate of 0.1 mM U(VI) within 150 min in the presence of carbonate, without the assistance of any electron donors. During the photocatalytic process, U(VI) is reduced to form UO2+x. The hydrogel catalyst exhibits a high uranium extraction capacity of >434.5 mg g⁻1 and the products can be effectively eluted using a 0.1 M NaCO3 solution. Furthermore, this hydrogel catalyst offers excellent stability, good recyclability, outstanding antifouling activity, and ease of separation, all of which are desirable for seawater uranium extraction. Finally, the test in real seawater demonstrates the successful extraction of uranium from seawater using the prepared hydrogel catalyst.

Constructing 2D Polyphenols-Based Crosslinked Networks for Ultrafast and Selective Uranium Extraction from Seawater.

The role of tannins (TA), a well-known abundant and ecologically friendly chelating ligand, in metal capture has long been studied. Different kinds of TA-containing adsorbents are synthesized for uranium capture, while most adsorbents suffer from unfavorable adsorption kinetics. Herein, the design and preparation of a TA-containing 2D crosslinked network adsorbent (TANP) is reported. The ≈1.8-nanometer-thick TANP films curl up into micrometer-scale pores, which contribute to fast mass transfer and full exposure of active sites. The coordination environment of uranyl (UO2 2+) ions is explored by integrated analysis of U L3-edge XANES and EXAFS. Density functional theory calculations indicate the energetically favorable UO2 2+ binding. Consequently, TANP with excellent adsorption kinetics presents a high uranium capture capacity (14.62 mg-U g-Ads-1) and a high adsorption rate (0.97 mg g-1 day-1) together with excellent selectivity and biofouling resistance. Life cycle assessment and cost analysis demonstrate that TANP has tremendous potential for application in industrial-scale uranium extraction from seawater.

U and Co Dual Single-Atom Doped MXene for Accelerating Electrocatalytic Hydrogen Evolution Activity.

A large amount of radioactive waste is accumulated in the process of nuclear fuel preparation, causing serious pollution to the environment and abundant depleted uranium resources to be abandoned. One of the key issues affecting the development of nuclear energy is how to make full use of depleted uranium resources efficiently. Here, U element with unique coordination mode of 5f electron is spacer bonded to transition metal with 3d orbit through the adsorption and anchoring effect of MXene, thus U and Co dual doped MXene catalyst is constructed along with the comprehensive utilization of depleted uranium resources. The as-prepared U-Co/MXene catalyst demonstrates excellent overpotential of only 184 mV at -10 mA cm-2 and excellent stability up to 150 h, significantly surpassing the bare MXene substrate. Theoretical calculations indicate that the U and Co dual doping optimizes the electronic structure of MXene catalyst by forming the U-O-Co network, thereby improving the thermodynamics of H* adsorption during the catalytic transition state. This research opens up a new path for the recovery of depleted uranium resources and the development of functional actinide catalysts.

Emerging Nanomaterials toward Uranium Extraction from Seawater: Recent Advances and Perspectives.

Nuclear energy holds great potential to facilitate the global energy transition and alleviate the increasing environmental issues due to its high energy density, stable energy output, and carbon-free emission merits. Despite being limited by the insufficient terrestrial uranium reserves, uranium extraction from seawater (UES) can offset the gap. However, the low uranium concentration, the complicated uranium speciation, the competitive metal ions, and the inevitable marine interference remarkably affect the kinetics, capacity, selectivity, and sustainability of UES materials. To date, massive efforts have been made with varying degrees of success to pursue a desirable UES performance on various nanomaterials. Nevertheless, comprehensive and systematic coverage and discussion on the emerging UES materials presenting the fast-growing progress of this field is still lacking. This review thus challenges this position and emphatically focuses on this topic covering the current mainstream UES technologies with the emerging UES materials. Specifically, this review elucidates the causality between the physiochemical properties of UES materials induced by the intellectual design strategies and the UES performances and further dissects the relationships of materials-properties-activities and the corresponding mechanisms in depth. This review is envisaged to inspire innovative ideas and bring technical solutions for developing technically and economically viable UES materials.

Enhanced Uranium Extraction via Charge Dynamics and Interfacial Polarization in MoS2/GO Heterojunction Electrodes.

The removal of uranyl ions (UO2 2+) from water is challenging due to their chemical stability, low concentrations, complex water matrix, and technical limitations in extraction and separation. Herein, a novel molybdenum disulfide/graphene oxide heterojunction (MoS2/GO-H) is developed, serving as an effective electrode for capacitive deionization (CDI). By combining the inherent advantages of electroadsorption and electrocatalysis, an innovative electroadsorption-electrocatalysis system (EES) strategy is introduced. This system utilizes interface polarization at the MoS2 and GO interface, creating an additional electric field that significantly influences carrier behavior. The MoS2/GO-H electrode, with its extraordinary adsorption capacity of 805.57 mg g-1 under optimal conditions, effectively treated uranium-laden wastewater from a mine, achieving over 90% removal efficiency despite the presence of numerous competing ions at concentrations significantly higher than UO2 2+. Employing density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, it is found that the MoS2/GO-H total charge density at the Fermi level, enhanced by interfacial polarization, surpasses that of separate MoS2 and GO, markedly boosting conductivity and electrocatalytic effectiveness.

Encapsulation of Uranium Oxide in Multiwall WS2 Nanotubes.

Uranium is a high-value energy element, yet also poses an appreciable environmental burden. The demand for a straightforward, low energy, and environmentally friendly method for encapsulating uranium species can be beneficial for long-term storage of spent uranium fuel and a host of other applications. Leveraging on the low melting point (60 °C) of uranyl nitrate hexahydrate and nanocapillary effect, a uranium compound is entrapped in the hollow core of WS2 nanotubes. Followingly, the product is reduced at elevated temperatures in a hydrogen atmosphere. Nanocrystalline UO2 nanoparticles anchor within the WS2 nanotube lumen are obtained through this procedure. Such methodology can find utilization in the processing of spent nuclear fuel or other highly active radionuclides as well as a fuel for deep space missions. Moreover, the low melting temperatures of different heavy metal-nitrate hydrates, pave the way for their encapsulation within the hollow core of the WS2 nanotubes, as demonstrated herein.

Radiation-Induced Defects in Uranyl Trinitrate Solids.

Actinides are inherently radioactive; thus, ionizing radiation is emitted by these elements can have profound effects on its surrounding chemical environment through the formation of free radical species. While previous work has noted that the presence of free radicals in the system impacts the redox state of the actinides, there is little atomistic understanding of how these metal cations interact with free radicals. Herein, we explore the effects of radiation (UV and γ) on three U(VI) trinitrate complexes, M[UO2(NO3)3] (where M=K+, Rb+, Cs+), and their respective nitrate salts in the solid state via electron paramagnetic resonance (EPR) and Raman spectroscopy paired with Density Functional Theory (DFT) methods. We find that the alkali salts form nitrate radicals under UV and γ irradiation, but also note the presence of additional degradation products. M[UO2(NO3)3] solids also form nitrate radicals and additional DFT calculations indicate the species corresponds to a change from the bidentate bound nitrate anion into a monodentate NO3 • radical. Computational studies also highlight the need to include the second sphere coordination environment around the [UO2(NO3)3]0,1 species to gain agreement between the experimental and predicted EPR signatures.

U(V) Stabilization via Aliovalent Incorporation of Ln(III) into Oxo-salt Framework.

Pentavalent uranium compounds are key components of uranium's redox chemistry and play important roles in environmental transport. Despite this, well-characterized U(V) compounds are scarce primarily because of their instability with respect to disproportionation to U(IV) and U(VI). In this work, we provide an alternate route to incorporation of U(V) into a crystalline lattice where different oxidation states of uranium can be stabilized through the incorporation of secondary cations with different sizes and charges. We show that iriginite-based crystalline layers allow for systematically replacing U(VI) with U(V) through aliovalent substitution of 2+ alkaline-earth or 3+ rare-earth cations as dopant ions under high-temperature conditions, specifically Ca(UVIO2)W4O14 and Ln(UVO2)W4O14 (Ln=Nd, Sm, Eu, Gd, Yb). Evidence for the existence of U(V) and U(VI) is supported by single-crystal X-ray diffraction, high energy resolution X-ray absorption near edge structure, X-ray photoelectron spectroscopy, and optical absorption spectroscopy. In contrast with other reported U(V) materials, the U(V) single crystals obtained using this route are relatively large (several centimeters) and easily reproducible, and thus provide a substantial improvement in the facile synthesis and stabilization of U(V).

A New Molybdenum Blue Structure Type: How Uranium Expands this Family of Polyoxometalates.

The assembly of molybdenum polyoxometalates (POMs) has afforded large discrete nanoclusters with varied degrees of reduction such as the ~20 % reduced molybdenum blues. While many heterometals have been incorporated into these clusters to afford new properties, uranium has yet to be reported. Here we report the first uranium containing molybdenum blue clusters and the unique properties exhibited by this incorporation. The uranyl ion (UO2 2+) directs formation of Mo72U8, a square POM comprised of two faces connected by eight edge-sharing molybdenum dimers. Mo72U8, a chiral cluster, crystallizes as a racemic mixture and, in the solid state, has a 'negative' charge localized on one face of the cluster opposite the 'positively' charged face of another cluster. Using U(IV) as both heterometal and molybdenum reductant afforded crystals of Mo97U10, a wheel cluster with a heptamolybdate cap on one face. Mo97U10 dissociates in solution, losing the heptamolybdate, to form Mo90U10. Using more solvent during synthesis afforded crystals of Mo90U10S4 which, instead of heptamolybdate, contains four sulfate ions. Crystals of Mo90U10S4 undergo a dehydration induced phase change where clusters form a sheet through oxide bridges. Half of the bridges are cation-cation interactions between the uranyl oxygen atom and molybdenum, the first reported of this kind.

Hydrothermal alteration processes in monzogranite: a case study from the Eastern Desert of Egypt: implications from remote sensing, geochemistry and mineralogy.

The South Eastern Desert (SED) of Egypt is one of the most promising areas in Egypt; it is widely explored for exploring the rare earth elements (REEs) and uranium-bearing ores. It is a main part of the Arabian-Nubian Shield (ANS). Therefore, the present study concerns with Sikait-Nugrus area as one of the most prolific sites in this region. The study provides a detailed geological, structural, and mineralogical investigation of the monzogranites to describe and characterize the various alteration types and sequence. For this purpose, remote sensing, geochemical and petrographical techniques were applied. The remote sensing technique helped in constructing a detailed geologic map of the study area to follow up strictly the alteration zone of the Sikait-Nugrus area. Petrographically, the granites predominates in the study area, they are described as slightly and highly altered monzogranites. The slightly altered one is composed mainly of quartz (~ 20-35%), alkali feldspar (~ 25-30%), plagioclase (~ 25-30%), and mica (~ 5-15%), while accessory minerals are represented by zircon and monazite. On the other hand, the portion of this granite close to the shearing zone is intensively altered and characterized by sericitization as the main alteration processes. This sheared portion is characterized by accessory minerals as, uranothorite, allanite, fluorite and Nb-minerals (ishikawaite). Minerlogically, the altered monzogranites are predominated by the following mineral groups: (1) radioactive minerals as uranyl silicates (soddyite, uranophane and kasolite), and thorium minerals (thorite and uranothorite), (2) Nb-Ta minerals (betafite, plumbobetafite, columbite, fergusonite, and aeschynite), (3) REE minerals (monazite, cheralite and xenotime), and (4) zircon and fluorite as accessory minerals. Geochemically, the recorded pattern of the REEs tetrad effect (M-type) for the highly altered samples indicate that these granites are highly evolved and affected by late stage of hydrothermal alteration and the effective water-rich alteration processes that connected to intensive physico-chemical changes. The total REE concentrations equal 241.8 and 249.75 ppm for the highly and slightly altered samples. A significant mass change (MC) was analyzed by the isocon technique (22.95 & 11.11) and volume change (VC) (1.8 &-7.99) for the highly and slightly altered samples, respectively. The mass balance calculations and the isocon diagrams revealed that some major oxides were removed from the slightly altered monzogranites and transformed later into highly altered monzogranites with increasing the alteration intensity due to the impacts of hydrothermal alteration processes. The studied area is virgin, where no detailed studies have been applied to this region. It is extendable to other parts of the Arabian-Nubian Shield in around the Red Sea in Egypt, Sudan, Saudi Arabia and Yemen. The applied technical workflow is also extendible to other surface analogues everywhere.

Aneurinibacillus uraniidurans sp. nov., a uranium-resistant bacterium isolated from uranium-contaminated soil.

A novel Gram-positive strain, B1T, was isolated from uranium-contaminated soil. The strain was aerobic, rod-shaped, spore-forming, and motile. The strain was able to grow at 20-45 °C, at pH 6.0-9.0, and in the presence of 0-3 % (w/v) NaCl. The complete genome size of the novel strain was 3 853 322 bp. The genomic DNA G+C content was 45.5 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain B1T has the highest similarity to Aneurinibacillus soli CB4T (96. 71 %). However, the novel strain showed an average nucleotide identity value of 89.02 % and a digital DNA-DNA hybridization value of 37.40 % with strain CB4T based on the genome sequences. The major fatty acids were iso-C15 : 0 and C16 : 0. The predominate respiratory quinone was MK7. Diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, unidentified phospholipids, an unidentified aminolipid and an unidentified lipid were identified as the major polar lipids. The phylogenetic, phenotypic, and chemotaxonomic analyses showed that strain B1T represents a novel species of the genus Aneurinibacillus, for which the name Aneurinibacillus uraniidurans sp. nov. is proposed. The type strain is B1T (=GDMCC 1.4080T=JCM 36228T). Experiments have shown that strain B1T demonstrates uranium tolerance.

Effects of Detoxifying Substances on Uranium Removal by Bacteria Isolated from Mine Soils: Performance, Mechanisms, and Bacterial Communities.

In this study, we investigated the effect of detoxifying substances on U(VI) removal by bacteria isolated from mine soil. The results demonstrated that the highest U(VI) removal efficiency (85.6%) was achieved at pH 6.0 and a temperature of 35 °C, with an initial U(VI) concentration of 10 mg/L. For detoxifying substances, signaling molecules acyl homoserine lactone (AHLs, 0.1 µmol/L), anthraquinone-2, 6-disulfonic acid (AQDS, 1 mmol/L), reduced glutathione (GSH, 0.1 mmol/L), selenium (Se, 1 mg/L), montmorillonite (MT, 1 g/L), and ethylenediaminetetraacetic acid (EDTA, 0.1 mmol/L) substantially enhanced the bacterial U(VI) removal by 34.9%, 37.4%, 54.5%, 35.1%, 32.8%, and 47.8% after 12 h, respectively. This was due to the alleviation of U(VI) toxicity in bacteria through detoxifying substances, as evidenced by lower malondialdehyde (MDA) content and higher superoxide dismutase (SOD) and catalase (CAT) activities for bacteria exposed to U(VI) and detoxifying substances, compared to those exposed to U(VI) alone. FTIR results showed that hydroxyl, carboxyl, phosphorus, and amide groups participated in the U(VI) removal. After exposure to U(VI), the relative abundances of Chryseobacterium and Stenotrophomonas increased by 48.5% and 12.5%, respectively, suggesting their tolerance ability to U(VI). Gene function prediction further demonstrated that the detoxifying substances AHLs alleviate U(VI) toxicity by influencing bacterial metabolism. This study suggests the potential application of detoxifying substances in the U(VI)-containing wastewater treatment through bioremediation.

Radiological Analyses of 226Ra and 238U in Surface Water and Sediments from the Jackpile Member of the Morrison Formation, Pueblo of Laguna, New Mexico.

Surface water and sediments from the Jackpile mine, St. Anthony mine, Rio Paguate, Rio Moquino, and Mesita Dam areas near Pueblo of Laguna, New Mexico, were analyzed for 226Ra and U using gamma (γ) spectroscopy and inductively coupled plasma mass spectroscopy, respectively. Activity ratios for 226Ra/238U for solid samples range from 0.34 ± 0.13 to 16 ± 2.9, which reflect uranium transport and accumulation (<1), relatively pristine material in secular equilibrium (1), and removal of uranium by weathering (>1). Concentrations ranging from 80 to 225 µg L-1 U were detected in unfiltered water samples near the Jackpile mine. Water samples upstream and downstream from the mine contained concentrations ranging from 12 to 15 µg L-1 U. Water samples collected from the North Pit standing pond in the Jackpile mine contained as much as 1560 pCi L-1 of 226Ra, and passing the water through a 0.2 µM filter did not substantially reduce the activity of 226Ra in the water. 234Th and 226Ra are in secular equilibrium in this water, while radon gas was lost from the water. The results of the current study provide insight into the distribution of U-series radionuclides in the Pueblo of Laguna area, including detection of high levels of radioactivity in water at some locations within the Jackpile mine.