The accumulation of Fe and Mn in seasonally stratified drinking water reservoirs adversely impacts water quality. To control issues with Fe and Mn at the source, some drinking water utilities have deployed hypolimnetic oxygenation systems to create well-oxygenated conditions in the water column that are favorable for the oxidation, and thus removal, of Fe and Mn. However, in addition to being controlled by dissolved oxygen (DO), Fe and Mn concentrations are also influenced by pH and metal-oxidizing microorganisms. We studied the response of Fe and Mn concentrations to hypolimnetic oxygenation in a shallow drinking water reservoir in Vinton, Virginia, USA by sequentially activating and deactivating an oxygenation system over two summers. We found that maintaining well-oxygenated conditions effectively prevented the accumulation of soluble Fe in the hypolimnion. However, while the rate of Mn oxidation increased under well-oxygenated conditions, soluble Mn still accumulated in the slightly acidic to neutral (pH 5.6 to 7.5) hypolimnion. In parallel, we conducted laboratory incubation experiments, which showed that the presence of Mn-oxidizing microorganisms increased the rate of Mn oxidation in comparison with rates under oxic, abiotic conditions. Combined, our field and laboratory results demonstrate that increasing DO concentrations in the water column is important for stimulating the oxidation of Fe and Mn, but that the successful management of Mn is also tied to the activity of Mn-oxidizing organisms in the water column and favorable (neutral to alkaline) pH.
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http://dx.doi.org/10.1016/j.watres.2016.09.038 | DOI Listing |
Anal Methods
December 2024
Competence Centre on Digital Agriculture, São Leopoldo, RS, Brazil.
The use of pesticides has significantly increased and proliferated following the technological advancements established by the green revolution, aimed at boosting agricultural productivity. The extensive use of man-made chemicals as fertilizer and pesticides has consequently led to large-scale application, which has led to a number of environmental and human health problems. This study has helped to develop a laser-induced graphene (LIG) sensor for the detection of the most widely used herbicide in the world, glyphosate.
View Article and Find Full Text PDFFront Nutr
December 2024
School of Public Health, Adama Hospital Medical College, Adama, Oromia, Ethiopia.
Background: Wasting, stunting, and underweight in children are complex health challenges shaped by a combination of immediate, underlying, and systemic factors. Even though copious data demonstrates that the causation routes for stunting and wasting are similar, little is known about the correlations between the diseases in low- and middle-income nations.
Objective: The objective of this study is to evaluate the factors that concurrently affect wasting, stunting, and underweight in <5-year-olds with severe acute malnutrition (SAM).
ACS Omega
December 2024
Department of Chemistry and Biochemistry, Jackson State University, Jackson, Mississippi 39217, United States.
The short-chain (C to C) and ultrashort-chain (C to C) per- and polyfluoroalkyl substances (PFAS) are bioaccumulative, carcinogenic to humans, and harder to remove using current technologies, which are often detected in drinking and environmental water samples. Herein, we report the development of nonafluorobutanesulfonyl (NFBS) and polyethylene-imine (PEI)-conjugated FeO magnetic nanoparticle-based magnetic nanoadsorbents and demonstrated that the novel adsorbent has the capability for highly efficient removal of six different short- and ultrashort-chain PFAS from drinking and environmental water samples. Reported experimental data indicates that by capitalizing the cooperative hydrophobic, fluorophilic, and electrostatic interaction processes, NFBS-PEI-conjugated magnetic nanoadsorbents can remove ∼100% short-chain perfluorobutanesulfonic acid within 30 min from the water sample with a maximum absorption capacity of ∼234 mg g.
View Article and Find Full Text PDFWorld J Gastroenterol
December 2024
Department of Gastroenterology, The First Hospital of Lanzhou University, Lanzhou 730000, Gansu Province, China.
Background: () infection exhibits a familial clustering phenomenon.
Aim: To investigate the prevalence of infection, identify associated factors, and analyze patterns of transmission within families residing in the community.
Methods: From July 2021 to September 2021, a total of 191 families (519 people) in two randomly chosen community health service centers in the Chengguan District of Lanzhou in Gansu Province, were recruited to fill out questionnaires and tested for infection.
Biogeochemistry
December 2024
Department of Natural Resources and the Environment, University of New Hampshire, 56 College Road, Durham, NH USA.
Unlabelled: Climate and atmospheric deposition interact with watershed properties to drive dissolved organic carbon (DOC) concentrations in lakes. Because drivers of DOC concentration are inter-related and interact, it is challenging to assign a single dominant driver to changes in lake DOC concentration across spatiotemporal scales. Leveraging forty years of data across sixteen lakes, we used structural equation modeling to show that the impact of climate, as moderated by watershed characteristics, has become more dominant in recent decades, superseding the influence of sulfate deposition that was observed in the 1980s.
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