Background The mortality of the SARS-CoV-2 virus (COVID-19) has been associated with a pulmonary inflammatory response resulting in hypoxemia and rapid clinical decline. PREVENT is an ongoing prospective multicenter Phase II randomized controlled trial where patients hospitalized with COVID-19 pneumonia are randomized to low dose radiation therapy (RT) versus control (clinicaltrials.gov, NCT04466683). We describe the inpatient onboarding process of the center contributing the largest number of patients to this trial. Materials and methods COVID-19 hospital admissions were attained by the clinical research manager and radiation oncologist daily. Text message contact was made with infectious disease, critical care, and nursing staff with reciprocal discussion of the trial protocol and approval for virtual consulting of the patient. Witnessed informed consent was obtained first by telephone and later in person. Simulation and treatment (performed without a computer plan) was performed on a linear accelerator with one personal protective equipment-protected therapist moving in and out of the treatment room, and a second therapist manning the console. Following on-site dose calculation by physics, the radiation oncologist approved the fields prior to treatment delivery. Results Between August 28, 2020 and October 6, 2020, the first 10 enrolled patients on this multicenter trial were randomized and treated at our institution; no team member (research staff, radiation oncology) contracted COVID-19 while employing this protocol. Conclusion This represents the first published protocol to address efficient and safe recruitment of COVID-19 patients for a radiation oncology trial, serving as a model for conducting recruitment of COVID-19 patients for clinical trials.

After fluid administration for vasodilatory shock, vasopressors are commonly infused. Causes of vasodilatory shock include septic shock, post-cardiovascular surgery, post-acute myocardial infarction, postsurgery, other causes of an intense systemic inflammatory response, and drug -associated anaphylaxis. Therapeutic vasopressors are hormones that activate receptors-adrenergic: α1, α2, β1, β2; angiotensin II: AG1, AG2; vasopressin: AVPR1a, AVPR1B, AVPR2; dopamine: DA1, DA2. Vasopressor choice and dose vary widely because of patient and physician practice heterogeneity. Vasopressor adverse effects are excessive vasoconstriction causing organ ischemia/infarction, hyperglycemia, hyperlactatemia, tachycardia, and tachyarrhythmias. To date, no randomized controlled trial (RCT) of vasopressors has shown a decreased 28-day mortality rate. There is a need for evidence regarding alternative vasopressors as first-line vasopressors. We emphasize that vasopressors should be administered simultaneously with fluid replacement to prevent and decrease duration of hypotension in shock with vasodilation. Norepinephrine is the first-choice vasopressor in septic and vasodilatory shock. Interventions that decrease norepinephrine dose (vasopressin, angiotensin II) have not decreased 28-day mortality significantly. In patients not responsive to norepinephrine, vasopressin or epinephrine may be added. Angiotensin II may be useful for rapid resuscitation of profoundly hypotensive patients. Inotropic agent(s) (e.g., dobutamine) may be needed if vasopressors decrease ventricular contractility. Dopamine has fallen to almost no-use recommendation because of adverse effects; angiotensin II is available clinically; there are potent vasopressors with scant literature (e.g., methylene blue); and the novel V1a agonist selepressin missed on its pivotal RCT primary outcome. In pediatric septic shock, vasopressors, epinephrine, and norepinephrine are recommended equally because there is no clear evidence that supports the use of one vasoactive agent. Dopamine is recommended when epinephrine or norepinephrine is not available. New strategies include perhaps patients will be started on several vasopressors with complementary mechanisms of action, patients may be selected for particular vasopressors according to predictive biomarkers, and novel vasopressors may emerge with fewer adverse effects.

Despite increased attention on prevention and early aggressive treatment with antibiotics and smart fluid resuscitation, there remains high morbidity and mortality from septic shock globally (1). Frequently septic patients develop persistent distributive shock that often requires vasopressor infusion to restore adequate mean arterial pressure (MAP) in order to provide adequate perfusion to critical organs and tissues. Although there are a variety of catecholamines available to increase blood pressure in these critically ill patients, the unmet need for additional therapies remains because of the persistently high morbidity and mortality of septic shock.

Severe sepsis and septic shock continue to be an important problem in children, with hospital mortality rates for pediatric severe sepsis as high as 25%. CASE SUMMARY:Two pediatric patients with septic shock requiring high dose vasopressors, who were treated with angiotensin II as part of an open-label study. Both patients had a significant increase in mean arterial pressure shortly after initiation of angiotensin II, with a reduction of the dose of catecholamines and vasopressin infusions. Serious adverse events reported were not attributable to angiotensin II by investigators. One patient survived, and one died related to progressive cerebral edema. CONCLUSIONS:Angiotensin II may represent another therapeutic option for pediatric patients who remain hypotensive despite receiving fluids and standard vasopressor therapy and deserves further study.

As part of the FutureGen 2.0 Project, a design was developed for a first-of-its-kind, commercial-scale, near-zero emissions coal-fueled power plant that includes carbon capture and storage (CCS) in a deep saline reservoir. To assess storage site performance and meet the regulatory requirements of the Class VI Underground Injection Control Program for CO2 Geologic Sequestration, the FutureGen 2.0 Project evaluated, selected, and designed a suite of monitoring technologies for use in (1) evaluating CO2 mass balance, (2) detecting significant loss of CO2 containment, (3) tracking the spatial extent of the CO2 plume and advancement of the pressure front within the storage reservoir, and (4) identifying the occurrence and location of injection-related induced seismicity. The monitoring program design includes direct monitoring of the injection process (above ground and in the injection wells), injection-zone monitoring, early-leak-detection monitoring directly above the primary confining zone, and compliance monitoring within the lowermost underground source of drinking water (USDW); it also includes measurements of formation pressure and other geochemical/isotopic signatures that provide an indication of changes in CO2 concentration and/or brine composition, both within the injection zone and immediately above the primary confining zone. In addition to these direct measurements, several indirect geophysical monitoring technologies were included in the monitoring program design such as passive seismic and integrated surface deformation monitoring. Although the FutureGen 2.0 Project was suspended by the U.S. Department of Energy prior to implementation of the monitoring program design, this overview is provided with the hope that other current or future CCS projects will derive benefit from consideration of the approach and monitoring network configuration adopted by the project. (C) 2016 Elsevier Ltd. All rights reserved.

Several promising therapies assessed in the adult critically ill in large, multicenter randomized controlled trials (RCTs) were associated with significantly increased mortality in the intervention arms. Our hypothesis was that there would be wide ranges in sponsorship (industry or not), type(s) of intervention(s), use of DSMBs, presence of interim analyses and early stopping rules, absolute risk increase (ARI), and whether or not adequate prior proof-of-principle Phase II studies were done of RCTs that found increased mortality rates of the intervention compared to control groups. We reviewed RCTs that showed a statistically significant increased mortality rate in the intervention compared to control group(s). We recorded source of sponsorship, sample sizes, types of interventions, mortality rates, ARI (as well as odds ratios, relative risks and number needed to harm), whether there were pre-specified interim analyses and early stopping rules, and whether or not there were prior proof-of-principle (also known as Phase II) RCTs. Ten RCTs (four industry sponsored) of many interventions (high oxygen delivery, diaspirin cross-linked hemoglobin, growth hormone, methylprednisolone, hetastarch, high-frequency oscillation ventilation, intensive insulin, NOS inhibition, and beta-2 adrenergic agonist, TNF-α receptor) included 19,126 patients and were associated with wide ranges of intervention versus control group mortality rates (25.7–59 %, mean 29.9 vs 17–49 %, mean 25 %, respectively) yielding ARIs of 2.6–29 % (mean 5 %). All but two RCTs had pre-specified interim analyses, and seven RCTs were stopped early. All RCTs were preceded by published proof-of-principle RCT(s), two by the same group. Seven interventions (except diaspirin cross-linked hemoglobin and the NOS inhibitor) were available for use clinically at the time of the pivotal RCT. Common, clinically available interventions used in the critically ill were associated with increased mortality in large, pivotal RCTs even though safety was often addressed by interim analyses and early stopping rules.

Laboratory experiments were conducted to evaluate the impact of supercritical carbon dioxide (scCO(2)) injection on aqueous and solid phase geochemistry, and subsequent changes in permeability. These experiments showed that brine displacement from the Mount Simon Sandstone cores (similar to 1200m depth) by scCO(2) was inefficient by advection, because the low viscosity scCO(2) flows predominantly in larger pores, leaving a significant amount of brine in smaller pores. Acidification caused by scCO2 injection resulted in significant increases in Mg2+, Na+, SO42- Al3+, and silica concentrations are likely from differing rates of carbonate, clay, albite, and K-feldspar dissolution. The mass of precipitates that formed over 1.2 years (NaCl, KCl, lead oxide, and forsterite) was small, as observed by electron microprobe analysis and did not influence permeability. Trace metals that increased during scCO(2) injection included Ba, Mn, Sr, Ni, Sn, Bi, Cu, Li, P, and Zn, and trace metals that decreased included Hg, Pb, and Co. The scCO(2) injection experiments also showed a moderate amount of particulate (iron oxide) movement correlated with the fraction of scCO2, but the sandstone permeability did not change, even after substantial (i.e., 115 pore volumes) scCO2 injection. Anaerobic and aerobic microbial growth was observed (23 and 14 times, respectively) correlated with higher scCO(2) concentration, but the calculated change in pore space occupied by the increase in biomass is insignificant. The small observed geochemical and microbial changes are not expected to reduce the ability to inject scCO(2) into the reservoir, but significant increases in trace metal concentrations could magnify the water quality impact of a potential leak of reservoir fluids into an overlying aquifer. (C) 2016 Elsevier Ltd. All rights reserved.

Use of gas-phase amendments for in situ remediation of inorganic contaminants in unsaturated sediments of the vadose zone may be advantageous, but there has been limited development and testing of gas remediation technologies. Treatment with ammonia gas has a potential for use in treating inorganic contaminants (such as uranium) because it induces a high pore-water pH, causing mineral dissolution and subsequent formation of stable precipitates that decrease the mobility of some contaminants. For field application of this treatment, further knowledge of ammonia transport in porous media and the geochemical reactions induced by ammonia treatment is needed. Laboratory studies were conducted to support calculations needed for field treatment design, to quantify advective and diffusive ammonia transport in unsaturated sediments, to evaluate inter-phase (gas/sediment/pore water) reactions, and to study reaction-induced pore-water chemistry changes as a function of ammonia delivery conditions, such as flow rate, gas concentration, and water content. Uranium-contaminated sediment was treated with ammonia gas to demonstrate U immobilization. Ammonia gas quickly partitions into sediment pore water and increases the pH up to 13.2. Injected ammonia gas advection front movement can be reasonably predicted by gas flow rate and equilibrium partitioning. The ammonia gas diffusion rate is a function of the water content in the sediment. Sodium, aluminum, and silica pore-water concentrations increase upon exposure to ammonia and then decline as aluminosilicates precipitate when the pH declines due to buffering. Up to 85% of the water-leachable U was immobilized by ammonia treatment.

An injectable permeable reactive barrier (PRB) technology was developed to sequester Sr-90 in groundwater through the in situ formation of calcium-phosphate mineral phases, specifically apatite that incorporates Sr-90 into the chemical structure. This injectable barrier technology extends the PRB concept to sites where groundwater contaminants are too deep or where site conditions otherwise preclude the application of more traditional trench-emplaced barriers. An integrated, multiscale development and testing approach was used that included laboratory bench-scale experiments, an initial pilot-scale field test, and the emplacement and evaluation of a 300-feet-long treatability-test-scale PRB. The apatite amendment formulation uses two separate precursor solutions, one containing a Ca-citrate complex and the other a Na-phosphate solution, to form apatite precipitate in situ. Citrate is needed to keep calcium in solution long enough to achieve a more uniform and areally extensive distribution of precipitate formation. In the summer of 2008, the apatite PRB technology was applied as a 91-m-long (300 feet) PRB on the down gradient edge of a Sr-90 plume beneath the Hanford Site in Washington State. The technology was deployed to reduce Sr-90 flux discharging to the Columbia River. Performance assessment monitoring data collected to date indicate that the barrier is meeting treatment objectives (i.e., 90% reduction in Sr-90 concentration). The average reduction in Sr-90 concentrations at four downgradient compliance monitoring locations was 95% relative to the high end of the baseline range approximately 1 year after treatment, and continues to meet remedial objectives more than 4 years after treatment.

The FutureGen 2.0 Project will design and build a first-of-its-kind, near-zero emissions coal-fueled power plant with carbon capture and storage (CCS). To assess storage site performance and meet the regulatory requirements of the Class VI Underground Injection Control (UIC) Program for CO2 Geologic Sequestration, the FutureGen 2.0 project will implement a suite of monitoring technologies designed to evaluate CO2 mass balance and detect any unforeseen loss in CO2 containment. The monitoring program will include direct monitoring of the reservoir, and early-leak-detection monitoring directly above the primary confining zone. This preliminary modeling study described here focuses on hypothetical leakage scenarios into the first permeable unit above the primary confining zone (Ironton Sandstone) and is used to support assessment of early-leak detection capabilities. Future updates of the model will be used to assess potential impacts on the lowermost underground source of drinking water (Saint Peter Sandstone) for a range of theoretical leakage scenarios. This preliminary modeling evaluation considers both pressure response and geochemical signals in the overlying Ironton Sandstone. This model is independent of the FutureGen 2.0 reservoir model in that it does not simulate caprock discontinuities, faults, or failure scenarios. Instead this modeling effort is based on theoretical, volumetric-rate based leakage scenarios. The scenarios include leakage of 1% of the total injected CO2 mass, but spread out over different time periods (20, 100, and 500 years) with each case yielding a different mass flux (i.e., smaller mass fluxes for longer duration leakage cases]. A brine leakage scenario using a volumetric leakage similar to the 20 year 1% CO2 case was also considered. A framework for the comparison of the various cases was developed based on the exceedance of selected pressure and geochemical thresholds at different distances from the point of leakage and at different vertical positions within the Ironton Sandstone. These preliminary results, and results from an updated models that incorporate additional site-specific characterization data, support development/refinement of the monitoring system design.

Laboratory experiments showed that low viscosity scCO(2) displacement of the brine into Mt Simon Sandstone and Eau Clair formation cores (FutureGen 2.0 Geologic Sequestration site, Jacksonville, Illinois, USA) was slow by advection, as scCO(2) travels predominantly in larger pores, leaving significant brine in smaller pores. As the scCO(2) displaces the brine in larger pores and carbonate partitions into the brine, the resulting acidification (pH 3 to 4) causes short-term mineral dissolution, ion desorption, and iron oxide particulate movement. Major aqueous biogeochemical changes observed over 1.2 years from core/brine/scCO(2) interactions includes: a) significant increase in Mg2+, K+, and SO42- concentrations (10s to 100s of mmol/L), b) dissolution of the hematite coating on the quartz grains, c) significant precipitation of NaCl and KCl, and d) some anaerobic microbial growth. Electron microprobe analysis showed the formation of some NaCl and KCl, but precipitates were too small a volume to significantly change permeability. Anaerobic microbial growth correlated with scCO(2) (23.5x in 1300h), was also too small to influence permeability. Iron oxide particulate movement was observed as a result of scCO(2) injection (acidification), but results could not conclusively correlate with formation permeability change. The electrical resistivity change of the rock core from 100% brine to 100% scCO(2) was in the expected range (3x to 5x), with most of the change observed between 70% to 100% scCO(2). Field scale conditions simulated using these laboratory-measured electrical resistivity changes indicated insufficient resolution was likely at the field site using surface electrodes due to the depth of injection (1200 m). Overall, injection of scCO(2) into the brine-filled Mt Simon sandstone cores resulted in small geochemical and microbial changes over the short-term (<1.5 years) with some iron oxide particulate movement. (C) 2014 Battelle Memorial Institute and the Authors. Published by Elsevier Limited.

The FutureGen 2.0 Project will design and build a first-of-its-kind, near-zero emissions coal-fueled power plant with carbon capture and storage (CCS). To assess storage site performance and meet the regulatory requirements of the Class VI Underground Injection Control (UIC) Program for CO2 Geologic Sequestration, the FutureGen 2.0 project will implement a suite of monitoring technologies designed to 1) evaluate CO2 mass balance and 2) detect any unforeseen loss in CO2 containment. The monitoring program will include direct monitoring of the injection stream and reservoir, and early-leak-detection monitoring directly above the primary confining zone. It will also implement an adaptive monitoring strategy whereby monitoring results are continually evaluated and the monitoring network is modified as required, including the option to drill additional wells in out-years. Wells will be monitored for changes in CO2 concentration and formation pressure, and other geochemical/isotopic signatures that provide indication of CO2 or brine leakage. Indirect geophysical monitoring technologies that were selected for implementation include passive seismic, integrated surface deformation, time-lapse gravity, and pulsed neutron capture logging. Near-surface monitoring approaches that have been initiated include surficial aquifer and surface- water monitoring, soil-gas monitoring, atmospheric monitoring, and hyperspectral data acquisition for assessment of vegetation conditions. Initially, only the collection of baseline data sets is planned; the need for additional near- surface monitoring will be continually evaluated throughout the design and operational phases of the project, and selected approaches may be reinstituted if conditions warrant. Given the current conceptual understanding of the subsurface environment, early and appreciable impacts to near-surface environments are not expected.

This report represents a synthesis and integration of basic and applied research into a system-scale model of the Hanford 300 Area groundwater uranium plume, supported by the U.S. Department of Energy’s Richland Operations (DOE-RL) office. The report integrates research findings and data from DOE Office of Science (DOE-SC), Office of Environmental Management (DOE-EM), and DOE-RL projects, and from the site remediation and closure contractor, Washington Closure Hanford, LLC (WCH). The three-dimensional, system-scale model addresses water flow and reactive transport of uranium for the coupled vadose zone, unconfined aquifer, and Columbia River shoreline of the Hanford 300 Area. The system-scale model of the 300 Area was developed to be a decision-support tool to evaluate processes of the total system affecting the groundwater uranium plume. The model can also be used to address “what if” questions regarding different remediation endpoints, and to assist in design and evaluation of field remediation efforts. For example, the proposed cleanup plan for the Hanford 300 Area includes removal, treatment, and disposal of contaminated sediments from known waste sites, enhanced attenuation of uranium hot spots in the vadose and periodically rewetted zone, and continued monitoring of groundwater with institutional controls. Illustrative simulations of polyphosphate infiltration were performedmore » to demonstrate the ability of the system-scale model to address these types of questions. The use of this model in conjunction with continued field monitoring is expected to provide a rigorous basis for developing operational strategies for field remediation and for defining defensible remediation endpoints.« less

The primary objective of this study is to summarize the laboratory investigations performed to evaluate short- and long-term effects of phosphate treatment on uranium leaching from 300 area smear zone sediments. Column studies were used to compare uranium leaching in phosphate-treated to untreated sediments over a year with multiple stop flow events to evaluate longevity of the uranium leaching rate and mass. A secondary objective was to compare polyphosphate injection, polyphosphate/xanthan injection, and polyphosphate infiltration technologies that deliver phosphate to sediment.

Management of severe sepsis, an acute illness with high morbidity and mortality, suffers from the lack of effective biomarkers and largely empirical predictions of disease progression and therapeutic responses. We conducted a genome-wide association study using a large randomized clinical trial cohort to discover genetic biomarkers of response to therapy and prognosis utilizing novel approaches, including combination markers, to overcome limitations of single-marker analyses. Sepsis prognostic models were dominated by clinical variables with genetic markers less informative. In contrast, evidence for gene-gene interactions were identified for sepsis treatment responses with genetic biomarkers dominating models for predicting therapeutic responses, yielding candidates for replication in other cohorts.

BACKGROUND:There have been conflicting reports on the efficacy of recombinant human activated protein C, or drotrecogin alfa (activated) (DrotAA), for the treatment of patients with septic shock.METHODS:In this randomized, double-blind, placebo-controlled, multicenter trial, we assigned 1697 patients with infection, systemic inflammation, and shock who were receiving fluids and vasopressors above a threshold dose for 4 hours to receive either DrotAA (at a dose of 24 μg per kilogram of body weight per hour) or placebo for 96 hours. The primary outcome was death from any cause 28 days after randomization.RESULTS:At 28 days, 223 of 846 patients (26.4%) in the DrotAA group and 202 of 834 (24.2%) in the placebo group had died (relative risk in the DrotAA group, 1.09; 95% confidence interval [CI], 0.92 to 1.28; P=0.31). At 90 days, 287 of 842 patients (34.1%) in the DrotAA group and 269 of 822 (32.7%) in the placebo group had died (relative risk, 1.04; 95% CI, 0.90 to 1.19; P=0.56). Among patients with severe protein C deficiency at baseline, 98 of 342 (28.7%) in the DrotAA group had died at 28 days, as compared with 102 of 331 (30.8%) in the placebo group (risk ratio, 0.93; 95% CI, 0.74 to 1.17; P=0.54). Similarly, rates of death at 28 and 90 days were not significantly different in other predefined subgroups, including patients at increased risk for death. Serious bleeding during the treatment period occurred in 10 patients in the DrotAA group and 8 in the placebo group (P=0.81).CONCLUSIONS:DrotAA did not significantly reduce mortality at 28 or 90 days, as compared with placebo, in patients with septic shock. (Funded by Eli Lilly; PROWESS-SHOCK ClinicalTrials.gov number, NCT00604214.).

A membrane bioreactor (MBR) process was employed for removing biodegradable organic matter (BOM) and ozonation disinfection byproducts (DBPs) exemplified by total aldehydes from ozonated potable water. The BOM removal was to prevent or reduce microbial regrowth in water distribution systems and to reduce DBP forming potential after ozonation. A mathematical modeling approach was used as a tool for performance prediction and process design with implication to process upscaling. The modeling protocol integrated adsorption and biodegradation in liquid and adsorbent phases with model parameters obtained from independent experiments. The BOM was expressed as biodegradable dissolved organic carbon (BDOC), assimilable organic carbon (AOC), and total aldehydes. The MBR studies demonstrated the process effectiveness in removing AOC, BDOC and total aldehydes, and validated the model's predictive capability. Sensitivity studies qualitatively evaluated parameters influencing process dynamics. The simulation studies were unique in examining shutdown and startup effects on process dynamics and process recovery.

Objective: REsearching severe Sepsis and Organ dysfunction in children: A gLobal perspective (RESOLVE), a phase III trial of drotrecogin alfa (activated) in pediatric severe sepsis, examined biomarker changes in inflammation and coagulation. This report describes biomarker profiles in early severe sepsis and the pharmacodynamic assessment of drotrecogin alfa (activated) in RESOLVE. Design: Serial measurements of interleukin-1&bgr;, interleukin-6, interleukin-8, interleukin-10, tissue necrosis factor-&agr;, procalcitonin, D-dimer, and thrombin-antithrombin complex were performed at baseline and daily over the first five study days. Protein C levels were performed at baseline and at the end of the 96-hr study drug infusion. Analysis of variance–based log-transformed data compared the treatment groups for each measured variable. Setting: One hundred four pediatric intensive care units in 18 countries. Patients: Four hundred seventy-seven children between 38 wks corrected gestational age and 17 yrs with sepsis-induced cardiovascular and respiratory dysfunction. Interventions: Drotrecogin alfa (activated). Measurements and Main Results: Pharmacodynamic activity of drotrecogin alfa (activated) compared with placebo was observed with reduction of D-dimer on day 1 (p < .01) and thrombin-antithrombin complex on days 1–4 (p < .05). There were no significant changes by treatment in multiple cytokines or procalcitonin. In the overall population, a median protein C difference was not observed (p > .05) with drotrecogin alfa (activated) administration compared with placebo, although a difference (median percentage change from baseline) in favor of drotrecogin alfa (activated) was observed in patients >1 yr old (p = .0449). Conclusions: While children in the RESOLVE trial were similar to adults in that they showed a relationship between severity of coagulation and inflammation abnormalities and mortality, their pharmacodynamic response to drotrecogin alfa (activated) differed with respect to changes in protein C activity and systemic inflammation.

Low water content sediments were treated with NH3 gas to evaluate changes in U mobility as a potential field remediation method for vadose zone contamination. Injection of NH3 gas created high dissolved NH3 concentrations that followed equilibrium behavior. High NH3 concentration led to an increase in pH from 8.0 to 11 to 13, depending on the water content and NH3 concentration. The increase in pore water pH resulted in a large increase in pore water cations and anions from mineral‐phase dissolution. Minerals showing the greatest dissolution included montmorillonite, muscovite, and kaolinite. Pore water ion concentrations then decreased with time. Simulations based on initial pore water ion concentrations indicated that quartz, chrysotile, calcite, diaspore, hematite, and Na‐boltwoodite (hydrous U silicate) should precipitate. Electrical resistivity and induced polarization tomography (ERT/IP) was able to nonintrusively track these NH3 partitioning, dissolution, and precipitations processes through changes in conductivity and chargeability. Ammonia treatment significantly decreases the amount of U present as adsorbed and aqueous species in field‐contaminated sediments. In contrast, sediments containing a large fraction of U associated with carbonates generally showed little change. Uranium leaching from sediments containing high Na‐boltwoodite decreased significantly by NH3 treatment, but x‐ray absorption near‐edge structure/extended x‐ray absorption fine structure showed no change in the Na‐boltwoodite concentration. Therefore, NH3 treatment of contaminated sediment acts to decrease the highly mobile aqueous and adsorbed U by incorporation into precipitates and appears to decrease mobility of some existing U precipitates (Na‐boltwoodite) as a result of mineral coating.