In arid environments, infiltration from ephemeral rivers is believed to be a primary source of groundwater recharge. However, ephemeral river studies have mostly focussed on estimation of ...transmission loss or riverbed infiltration rates. Where river flows lead to the development of perched aquifers, transmission loss and riverbed infiltration can be much greater than aquifer recharge, as much of the infiltrated water can subsequently be lost to evapotranspiration. The Woodforde River in central Australia has flowed on 34 occasions within the past 16 years. River sediments are highly permeable, but the river is incised into clay sands of lower permeability, leading to the development of a perched aquifer. During an intensively monitored flow, the downstream decrease in river discharge was approximately equal to the volume of the perched aquifer, indicating that infiltration is the main source of river loss during flows. The perched aquifer persists for several months or longer, and water levels decline slowly over time. Comparison between chloride concentrations of river water and soil water from beneath the perched aquifer suggests that 25% of this water leaks through the low permeability sediments to recharge the deep aquifer. The remainder is used by the riparian vegetation or lost to evaporation.
•We examine transmission loss, infiltration and recharge from an ephemeral river.•A perched aquifer forms within the river channel following river flows.•The measured transmission loss is approximately equal to the volume of the perched aquifer sediments.•A chloride balance approach is used to partition infiltration into recharge and evapotranspiration.
Purpose of Review
Pediatric oncology patients frequently experience episodes of prolonged neutropenia which puts them at high risk for infection with significant morbidity and mortality. Here, we ...review the data on infection prophylaxis with a focus on both pharmacologic and ancillary interventions. This review does not include patients receiving hematopoietic stem cell transplantation.
Recent Findings
Patients with hematologic malignancies are at highest risk for infection. Bacterial and fungal prophylaxis decrease the risk of infection in certain high-risk groups. Ancillary measures such as ethanol locks, chlorhexidine gluconate baths, GCSF, IVIG, and mandatory hospitalization do not have enough data to support routine use. There is limited data on risk of infection and role of prophylaxis in patients receiving immunotherapy and patients with solid tumors. Patients with Down syndrome and adolescent and young adult patients may benefit from additional supportive care measures and protocol modifications.
Summary
Consider utilizing bacterial and fungal prophylaxis in patients with acute myeloid leukemia or relapsed acute lymphoblastic leukemia. More research is needed to evaluate other supportive care measures and the role of prophylaxis in patients receiving immunotherapy.
Weathering of mine waste rock can result in high concentrations of zinc (Zn) and cadmium (Cd) in surface and ground water. Design and implementation of mitigation measures requires an understanding ...of the mineralogical occurrence of Zn and Cd within the waste rock as well as the subsequent weathering and leaching processes. Recent geochemical studies have focused on the characterization of selenium and arsenic leaching from sphalerite and pyrite in waste rock from coal mines in the Elk Valley, British Columbia, Canada. Data collected from these studies provide an opportunity to evaluate the distribution and behavior of Zn and Cd. The abundance and mineralogical association of Zn and Cd were determined in waste rock placed at different times in the dump and leaching of Zn and Cd at the dump-scale was estimated by analyzing porewater and effluent water samples in a rock drain. Mean contents of Zn and Cd in the waste rock samples (n = 260) were 152 mg/kg (range: 48.4–591 mg/kg) and 3.02 mg/kg (range: 0.97–7.56 mg/kg), respectively. Electron microprobe analysis showed Zn and Cd are present in rock samples as primary sphalerite and sorbed onto secondary Fe oxides. The mean concentrations of Zn and Cd in porewater in the dump (n = 121) were 231 μg/L (range: 4.27–1046 μg/L) and 0.61 μg/L (range: <0.01–6.85 μg/L), respectively. The sorption onto secondary Fe oxides is identified as the sink for aqueous Zn and Cd in the dump. Under the oxidizing conditions that exist throughout much of the dump, Fe oxides will likely be a long-term sink for aqueous Zn and Cd. Mean concentrations of Zn and Cd in the rock drain water were 56.4 μg/L (range: 1.2–523 μg/L, n = 213) and 1.53 μg/L (range: 0.004–3.92 μg/L, n = 209), respectively. As such, these low concentrations are attributed to dilution by drain waters sourced upstream of the dump and sorption of Zn and Cd onto secondary Fe oxides and calcite precipitated in the drain within 200 m after discharge from the dump. The relative increase of Cd concentration in rock drain water compared to porewater can be because of its lower affinity for the sorption onto secondary Fe oxides and calcite. This study suggests that the mobility of Zn and Cd from the weathering of any low sulfide – high carbonate waste rocks will be limited because the precipitation of secondary Fe oxides and calcite provide a strong internal geochemical control on Zn and Cd mobilization.
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•Oxidation of sphalerite releases Zn and Cd into porewater of oxic coal waste rock dumps.•Sorption onto secondary Fe-oxides is a sink for Zn and Cd within dumps.•Sorption onto secondary Fe-oxides and calcite control Zn and Cd in rock drain water discharged from the dump.•Mobility of Zn and Cd from weathering of low sulfide–high carbonate waste rocks is limited.
The presence of per- and polyfluoroalkyl substances (PFAS) in U.S. drinking water has recently garnered significant attention from the media, federal government, and public health professionals. ...While concerns for PFAS exposure continue to mount, the general public's awareness and knowledge of the contaminant has remained unknown. This exploratory study sought to fill this data gap by administering a nationwide survey in which the awareness of PFAS and community contamination, awareness of PFAS containing products and intentions to change product use, and awareness and concern about PFAS in drinking water were assessed. The results indicated that almost half the respondents had never heard of PFAS and do not know what it is (45.1%). Additionally, 31.6% responded that they had heard of PFAS but do not know what it is. A large portion of respondents (97.4%) also responded that they did not believe their drinking water had been impacted by PFAS. Demographic association did not influence knowledge of PFAS or levels of concern with PFAS in drinking water. The strongest predictor of PFAS awareness was awareness due to known community exposure. The respondents aware of community exposure were more likely to have knowledge of PFAS sources, change their use of items with potential PFAS contamination, and answer that their drinking water sources were also contaminated with PFAS. Based on the received responses, PFAS information and health risks need to be better communicated to the public to help increase awareness. These efforts should also be coordinated between government agencies, utilities, the research community, and other responsible entities to bolster their effectiveness.
Non-hepatic causes of hyperammonaemia are uncommon relative to hepatic aetiologies. An adolescent female was admitted to the hospital with a diagnosis of very severe aplastic anaemia. During her ...treatment with immunosuppressive therapy, she developed neutropenic enterocolitis, pseudomonal bacteraemia and hyperammonaemia. A combination of intermittent haemodialysis and high-volume continuous veno-venous haemodiafiltration (CVVHDF) was required to manage the hyperammonaemia. Despite a thorough investigation, there were no hepatic, metabolic or genetic aetiologies identified that explained the hyperammonaemia. The hyperammonaemia resolved only after the surgical resection of her inflamed colon, following which she was successfully weaned off from the renal support. This is a novel case report of hyperammonaemia of non-hepatic origin secondary to widespread inflammation of the colon requiring surgical resection in an immunocompromised patient. This case also highlights the role of high-volume CVVHDF in augmenting haemodialysis in the management of severe refractory hyperammonaemia.
The goal of this study was to assess the efficacy of an after-school, peer-led, healthy living program on adiposity, self-efficacy, and knowledge of healthy living behaviors in children living in a ...remote isolated First Nation.
A quasi-experimental trial with a parallel nonequivalent control arm was performed with 151 children in Garden Hill First Nation during the 2010-2011 and 2011-2012 school years. Fourth grade students were offered a 5-month, peer-led intervention facilitated by high school mentors between January and May of each school year; students in the control arm received standard curriculum. The main outcome measures were waist circumference (WC) and BMI z score. Secondary outcome measures included healthy living knowledge and self-efficacy.
Fifty-one children (mean ± SD age: 9.7 ± 0.4 years; BMI z score: 1.46 ± 0.84) received the intervention, and 100 children were in the control arm. At baseline, WC (79.8 vs 83.9 cm), BMI z score (1.46 vs 1.48), and rates of overweight/obesity (75% vs 72%) did not differ between arms. After the intervention, the change in WC (adjusted treatment effect: -2.5 cm 95% confidence interval (CI): -4.1 to -0.90; P = .002) and BMI z score (adjusted treatment effect: -0.09 95% CI: -0.16 to -0.03; P = .007) were significantly lower in the intervention arm compared to the control arm. The intervention arm also experienced improvements in knowledge of healthy dietary choices (2.25% 95% CI: -0.01 to 6.25; P = .02). Self-efficacy was associated with the change in WC after the intervention (β = -7.9, P = .03).
An after-school, peer-led, healthy living program attenuated weight gain and improved healthy living knowledge in children living in a remote isolated First Nation.
Abstract
Primary Subject area
Emergency Medicine - Paediatric
Background
While the management of febrile neutropenia in patients with cancer has clear, evidence-based guidelines, the management of ...previously healthy, immunocompetent children with a febrile illness and first episode of neutropenia is less understood. These patients are often similarly treated with empiric antibiotics and hospitalization despite studies demonstrating that this population, if they are well-appearing with a short history of neutropenia, is at low risk of serious bacterial infections. Therefore, less aggressive management should be considered in patients meeting low risk criteria.
Objectives
The aim of our quality improvement (QI) study was to decrease the number of unnecessary hospitalizations and empiric antibiotics prescribed by 50% over a 12-month period for otherwise healthy, well appearing patients presenting to the emergency department (ED) with a first episode of febrile neutropenia.
Design/Methods
A team of stakeholders from Hematology, Infectious Disease, Pediatrics and Emergency Medicine was assembled. A review of the literature, peer institutions and local practices of managing febrile neutropenia in healthy children was performed. Using the Model for Improvement, a guideline for the management of healthy children with first episode of febrile neutropenia was developed and refined using PDSA cycles. In January 2020, the guideline was launched for clinical use in the ED. Education, targeted audit and feedback, pathway modifications, and reminders were used to address knowledge gaps and staff turnover. A family of measures was analyzed using run charts and statistical process control (SPC) methods.
Results
Eighteen months of baseline data identified nineteen low risk patients with 84% either hospitalized and/or received antibiotics. It was also uncovered that many patients were misdiagnosed with neutropenia by excluding bands from the absolute neutrophil count (ANC). After the first twelve months of the intervention, sixteen patients met low risk criteria. Hospitalization and/or antibiotics use for this population decreased to 25% and all blood cultures were negative. Recognition of true severe febrile neutropenia also improved. Forty-one patients had a neutrophil count < 0.5, but an ANC > 0.5. Hospitalization and/or antibiotics use for this population decreased from 52% to 10%.
Conclusion
Through a multi-faceted, multidisciplinary QI study, we improved resource stewardship and value-based care by reducing unnecessary hospitalizations and antibiotics in low risk patients with a first episode of febrile neutropenia. Next steps include iterations to the guideline to increase impact along with sustainability planning. This work can easily be adopted by other pediatric and community sites caring for children.
Abstract
BACKGROUND
Central nervous system (CNS) germinomas are radiotherapy (RT)-sensitive tumors with excellent survival. Current treatment strategies combine chemotherapy with RT to reduce the ...field and dose of RT. There is no standard treatment for germinomas originating in the basal ganglia/thalami (BGTG) given their rarity and poorly-defined imaging characteristics. Craniospinal (CSI), whole brain (WBI), whole ventricle (WVI), and focal RT have been previously utilized; however, the optimal strategy remains unclear.
METHODS
Retrospective multi-institutional analysis was conducted across 18 institutions in four countries.
RESULTS
For 46 cases with non-metastatic BGTG, the event-free survival (EFS) was 86.9% at both 5 and 10 years, while overall survival (OS) was 100%, and 95.7% respectively at 5 and 10 years. Median RT dose and range for the various treatment volumes were as follows: CSI (n=10): 2340 cGy (1980–3060 cGy), WBI (n=8): 2340 (1800–3000 cGy), WVI (n=14): 2340 cGy (1800–2550 cGy), focal (n=9): 3600 cGy (3060–5400 cGy). There was no statistically significant difference in the EFS based on RT modality (p=0.57), but EFS for subjects with CSI and WBI were both 100%. The three subjects who received chemotherapy alone had significantly lower EFS than those who received chemotherapy and RT (p=0.001), but were salvageable with RT.
CONCLUSION
In the largest study to date for BGTG, there were no significant differences in outcomes between patients who received CSI, WBI, WVI or focal RT. This group of patients should be included in future prospective clinical trials, and a more limited RT field may be considered.
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