Sorption of Soil Carbon Dioxide by Biochar and Engineered Porous Carbons.

CO is 45 to 50 times more concentrated in soil than in air, resulting in global diffusive fluxes that outpace fossil fuel combustion by an order of magnitude. Despite the scale of soil CO emissions, soil-based climate change mitigation strategies are underdeveloped. Existing approaches, such as enhanced weathering and sustainable land management, show promise but continue to face deployment barriers.

Sources of Blood Lead Exposure in Rural Bangladesh.

Lead (Pb) exposure is a major public health problem worldwide. Although high levels of Pb in blood in Bangladesh have been documented, the dominant Pb sources contributing to human exposure in rural Bangladesh have not been determined. Here, we first obtained blood from pregnant women from three rural Bangladeshi districts who were previously assessed by a case-control and sampling study, and we then conducted semistructured in-depth interviews to understand Pb exposure behavior and finally collected samples of the suspected Pb sources.

Cr(VI) reduction by Fe(II) sorbed to silica surfaces.

The reaction kinetics of groundwater contaminants are integral to evaluating the fate and transport of toxic metals in the environment. For redox sensitive contaminants, such as chromium, the kinetics of different reaction pathways can vary by orders of magnitude. Species-specific rate constants for iron-chromium oxidation-reduction reactions are unknown for many systems, especially in the presence of sorbing surfaces.

Isotopic Fingerprint of Uranium Accumulation and Redox Cycling in Floodplains of the Upper Colorado River Basin.

Uranium (U) groundwater contamination is a major concern at numerous former mining and milling sites across the Upper Colorado River Basin (UCRB), USA, where U(IV)-bearing solids have accumulated within naturally reduced zones (NRZs). Understanding the processes governing U reduction and oxidation within NRZs is critical for assessing the persistence of U in groundwater. To evaluate the redox cycling of uranium, we measured the U concentrations and isotopic compositions (δU) of sediments and pore waters from four study sites across the UCRB that span a gradient in sediment texture and composition.

Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite.

Quantifying Cr(VI) Production and Export from Serpentine Soil of the California Coast Range.

Hexavalent chromium (Cr(VI)) is generated in serpentine soils and exported to surface and groundwaters at levels above health-based drinking water standards. Although Cr(VI) concentrations are elevated in serpentine soil pore water, few studies have reported field evidence documenting Cr(VI) production rates and fluxes that govern Cr(VI) transport from soil to water sources. We report Cr speciation (i) in four serpentine soil depth profiles derived from the California Coast Range serpentinite belt and (ii) in local surface waters.

Isotopic Evidence for Reductive Immobilization of Uranium Across a Roll-Front Mineral Deposit.

We use uranium (U) isotope ratios to detect and quantify the extent of natural U reduction in groundwater across a roll front redox gradient. Our study was conducted at the Smith Ranch-Highland in situ recovery (ISR) U mine in eastern Wyoming, USA, where economic U deposits occur in the Paleocene Fort Union formation. To evaluate the fate of aqueous U in and adjacent to the ore body, we investigated the chemical composition and isotope ratios of groundwater samples from the roll-front type ore body and surrounding monitoring wells of a previously mined area.

Marine anoxia and delayed Earth system recovery after the end-Permian extinction.

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and (238)U/(235)U isotopic compositions (δ(238)U) of Upper Permian-Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions.

Physico-Chemical Heterogeneity of Organic-Rich Sediments in the Rifle Aquifer, CO: Impact on Uranium Biogeochemistry.

The Rifle alluvial aquifer along the Colorado River in west central Colorado contains fine-grained, diffusion-limited sediment lenses that are substantially enriched in organic carbon and sulfides, as well as uranium, from previous milling operations. These naturally reduced zones (NRZs) coincide spatially with a persistent uranium groundwater plume. There is concern that uranium release from NRZs is contributing to plume persistence or will do so in the future.

Isotopic and Geochemical Tracers for U(VI) Reduction and U Mobility at an in Situ Recovery U Mine.

In situ recovery (ISR) uranium (U) mining mobilizes U in its oxidized hexavalent form (U(VI)) by oxidative dissolution of U from the roll-front U deposits. Postmining natural attenuation of residual U(VI) at ISR mines is a potential remediation strategy. Detection and monitoring of naturally occurring reducing subsurface environments are important for successful implementation of this remediation scheme.

Uranium incorporation into amorphous silica.

High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal.

The Use of Emergency Medication Kits in Community Palliative Care: An Exploratory Survey of Views of Current Practice in Australian Home-Based Palliative Care Services.

Improving symptom management for palliative care patients has obvious benefits for patients and advantages for the clinicians, as workload demands and work-related stress can be reduced when the emergent symptoms of patients are managed in a timely manner. The use of emergency medication kits (EMKs) can provide such timely symptom relief. The purpose of this study was to conduct a survey of a local service to examine views on medication management before and after the implementation of an EMK and to conduct a nationwide prevalence survey examining the use of EMKs in Australia.

Supporting Family Caregivers With Palliative Symptom Management: A Qualitative Analysis of the Provision of an Emergency Medication Kit in the Home Setting.

Purpose: The purpose of this qualitative analysis was to examine the experiences of family caregivers supporting a dying person in the home setting. In particular, it explores caregivers' perceptions of receiving palliative care at home when supplied with an emergency medication kit (EMK).

Results: Most family caregivers described preexisting medication management strategies that were unable to provide timely intervention in symptoms.

Establishing research in a palliative care clinical setting: perceived barriers and implemented strategies.

There are many challenges in developing research projects in research-naïve clinical settings, especially palliative care where resistance to participate in research has been identified. These challenges to the implementation of research are common in nursing practice and are associated with attitudes towards research participation, and some lack of understanding of research as a process to improve clinical practice. This is despite the professional nursing requirement to conduct research into issues that influence palliative care practice.

Environmental speciation of actinides.

Although minor in abundance in Earth's crust (U, 2-4 ppm; Th, 10-15 ppm) and in seawater (U, 0.003 ppm; Th, 0.0007 ppm), light actinides (Th, Pa, U, Np, Pu, Am, and Cm) are important environmental contaminants associated with anthropogenic activities such as the mining and milling of uranium ores, generation of nuclear energy, and storage of legacy waste resulting from the manufacturing and testing of nuclear weapons.

ICDs and patients in palliative care: the clinical experience turned into clinical policy.

As the global population grows and ages, an increasing number of patients are being referred to specialist palliative care services with multiple comorbidities. A parallel increase in interventional cardiology technology, techniques, and availability means that an increasing minority of these patients are having an implantable cardioverter defibrillator device (ICD) in place. It is essential that issues relating to these devices are discussed early in patients' planning for end-of-life care, as the discharging of a device in a patient who has chosen not to be resuscitated will be contrary to their wishes.

Identifying the sources of subsurface contamination at the Hanford Site in Washington using high-precision uranium isotopic measurements.

In the mid-1990s, a groundwater plume of uranium (U) was detected in monitoring wells in the B-BX-BY Waste Management Area at the Hanford Site in Washington. This area has been used since the late 1940s to store high-level radioactive waste and other products of U fuel-rod processing. Using multiple-collector ICP source magnetic sector mass spectrometry, high-precision uranium isotopic analyses were conducted of samples of vadose zone contamination and of groundwater.