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1.
Chemosphere ; 262: 127567, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32755692

RESUMO

Acid mine drainage (AMD) is recognized as a challenge encountered by mining industries globally. Cyclic mineralization method, namely Fe2+ oxidation/mineralization-residual Fe3+ reduction-resultant Fe2+ oxidation/mineralization, could precipitate Fe and SO42- present in AMD into iron hydroxysulfate minerals and greatly improve the efficiency of subsequent lime neutralization, but the current Fe0-mediated reduction approach increased the mineralization cycles. This study constructed a bacteria-driven biomineralization system based on the reactions of Acidithiobacillus ferrooxidans-mediated Fe2+ oxidation and Acidiphilium multivorum-controlled Fe3+ reduction, and utilized water-dropping aeration and biofilm technology to satisfy the requirement of practical application. The resultant biofilms showed stable activity for Fe conversion: the efficiency of Fe2+-oxidation, Fe-precipitation, and Fe3+-reduction maintained at 98%, 32%, and 87%, respectively. Dissolved oxygen for Fe-oxidizing bacteria growth was continuously replenished by water-dropping aeration (4.2-7.2 mg/L), and the added organic carbon was mainly metabolized by Fe-reducing bacteria. About 89% Fe and 60% SO42- were precipitated into jarosite mineral after five biomineralization cycles. Fe was removed via forming secondary mineral precipitates, while SO42- was coprecipitated into mineral within the initial three biomineralization cycles, and then mainly precipitated with Ca2+ afterwards. Fe concentration in AMD was proven to directly correlate with subsequent lime neutralization efficiency. Biomineralization for five cycles drastically reduced the amount of required lime and neutralized sludge by 75% and 77%, respectively. The results in this study provided theoretical guidance for practical AMD treatment based on biomineralization technology.


Assuntos
Ferro/análise , Poluentes Químicos da Água/análise , Acidiphilium , Acidithiobacillus , Ácidos , Bactérias/metabolismo , Biodegradação Ambiental , Biomineralização , Compostos de Cálcio , Compostos Férricos , Ferro/metabolismo , Minerais , Mineração , Óxidos , Sulfatos , Poluentes Químicos da Água/metabolismo
2.
Sci Total Environ ; 751: 141869, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32882542

RESUMO

Black bloom occurs frequently in eutrophic waters. We investigated the conditions promoted the formation of black bloom via in-situ measurement in two aquatic microcosms and the effects of black bloom on the bacterial community composition. Although larger changes in dissolved oxygen (DO) were detected in the Hydrilla verticillata-dominated microcosm over the 90-day simulation, black bloom occurred more readily in the phytoplankton-dominated than macrophyte-dominated microcosm under conditions of O2 depletion and temperature above 30 °C. The sediment bacterial community composition shifted after black bloom; the relative abundance of Thiobacillus and Sideroxydans, which oxidize iron (Fe) and sulfur (S), decreased by 47% and 48%, respectively, in the phytoplankton-dominated microcosm and by 18% and 20% in the macrophyte-dominated microcosm. By contrast, Desulfatiglans increased by 13% and 19%, respectively, after black bloom. Furthermore, inter-taxa correlations remarkably changed according to co-occurrence network analysis. Thirty-six different taxa from the phylum to the genus level were identified as biomarkers of sediments collected before and after the black bloom event. Most of these biomarkers are related to Fe/S cycling in aquatic ecosystems.


Assuntos
Sedimentos Geológicos , Ferro , Bactérias , Ecossistema , Eutrofização , Ferro/análise , Lagos , Enxofre
3.
Bull Environ Contam Toxicol ; 105(3): 468-473, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32886144

RESUMO

Selenium (Se), iron (Fe), and free sulfides contents in pore waters were measured to study the liberation of soluble Se in suboxic conditions. The sediment core was collected in a salt marsh in Patos Lagoon estuary (southern Brazil), and it was obtained during a brackish water period, in a low intertidal stand vegetated by Spartina alterniflora. The redox potential (Eh), pH, andacid volatile sulfides (AVS) content were also investigated. Pore water results sustained the idea that S. alterniflora roots promote oxygen penetration to depths of ca. 10 cm below the salt marsh surface, increasing Eh and lowering the pH in this interval. High Se concentrations (e.g., 16.9 µg L-1), that are above US. EPA environmental criteria, were observed in the pore water to depths between 10 and 20 cm and are associated to low AVS contents and high concentrations of free sulfides. In the first 10 cm the lowering of Se contents probably happens due the low pH and biological volatilization of the metalloid.


Assuntos
Sedimentos Geológicos/química , Selênio/análise , Áreas Alagadas , Brasil , Estuários , Ferro/análise , Poaceae , Sulfetos/análise , Volatilização
4.
Environ Monit Assess ; 192(10): 619, 2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32885322

RESUMO

The present state of iron (Fe) and manganese (Mn) concentration in groundwater of Changchun city located within the Songnen Plain of northeastern China was evaluated in this study. Heavy metal sources, as well as triggering mechanism, were analyzed using a physicochemical, statistical and spatial approach. Results revealed that out of the 2600 samples analyzed, 214 (representing 8.24%) for Fe and 606 wells (representing 23.34%) for Mn exceeded the water standard. Organic matter-rich sediments and Fe-Mn nodules in aquifer and soil serve as sources of Fe and Mn. Organic and inorganic complex formations, as well as long residence time, were found to foster the release of Fe and Mn into groundwater. Additionally, pH and well depth was important in triggering Mn dissolution while groundwater mineralization, depth to the water table and well proximity to the river were found to have minimal/negligible effect on heavy metal mobilization. The removal of Fe and Mn from the water before use was proposed along with the sinking of deeper wells for groundwater exploitation to limit the use of polluted water.


Assuntos
Água Subterrânea , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Ferro/análise , Manganês/análise
5.
PLoS One ; 15(9): e0239739, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32986755

RESUMO

Rice is critical for sustainable food and nutritional security; however, nominal micronutrient quantities in grains aggravate malnutrition in rice-eating poor populations. In this study, we evaluated genetic diversity in grain iron (Fe) and zinc (Zn) contents using trait-linked simple sequence repeat (SSR) markers in the representative subset of a large collection of local and exotic rice germplasm. Results demonstrated that aromatic fine grain accessions contained relatively higher Fe and Zn contents in brown rice (BR) than coarse grain accessions and a strong positive correlation between both mineral elements. Genotyping with 24 trait-linked SSR markers identified 21 polymorphic markers, among which 17 demonstrated higher gene diversity and polymorphism information content (PIC) values, strongly indicating that markers used in current research were moderate to highly informative for evaluating the genetic diversity. Population structure, principal coordinate and phylogenetic analyses classified studied rice accessions into two fine grain specific and one fine and coarse grain admixture subpopulations. Single marker analysis recognized four ZnBR and single FeBR significant marker-trait associations (MTAs) contributing 15.41-39.72% in total observed phenotypic variance. Furthermore, high grain Fe and Zn contents linked marker alleles from significant MTAs were also identified. Collectively, these results indicate a wide genetic diversity exist in grain Fe and Zn contents of studied rice accessions and reveal perspective for marker-assisted biofortification breeding.


Assuntos
Grão Comestível/química , Grão Comestível/genética , Ferro/análise , Micronutrientes/análise , Repetições de Microssatélites/genética , Oryza/química , Oryza/genética , Polimorfismo Genético , Zinco/análise , Alelos , Biofortificação , Biomarcadores , Grão Comestível/classificação , Genes de Plantas , Genótipo , Oryza/classificação , Fenótipo , Filogenia , Melhoramento Vegetal , Locos de Características Quantitativas
6.
PLoS One ; 15(8): e0235421, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32756552

RESUMO

We investigated rock varnish, a thin, manganese- and iron-rich, dark surface crust, on basaltic lava flows and petroglyphs in the Owens and Rose Valleys (California) by portable X-ray fluorescence (pXRF) and femtosecond laser-ablation inductively-coupled-plasma mass spectrometry (fs-LA-ICPMS). The major element composition of the varnish was consistent with a mixture of Mn-Fe oxyhydroxides and clay minerals. As expected, it contained elevated concentrations of elements that are typically enriched in rock varnish, e.g., Mn, Pb, Ba, Ce, and Co, but also showed unusually high enrichments in U, Cu, and Th. The rare earth and yttrium (REY) enrichment pattern revealed a very strong positive cerium (Ce) anomaly and distinct negative europium (Eu) and Y anomalies. The light rare earth elements (REE) were much more strongly enriched than the heavy REY. These enrichment patterns are consistent with a formation mechanism by leaching of Mn and trace elements from aeolian dust, reprecipitation of Mn and Fe as oxyhydroxides, and scavenging of trace elements by these oxyhydroxides. We inferred accumulation rates of Mn and Fe in the varnish from their areal densities measured by pXRF and the known ages of some of the lava flow surfaces. The areal densities of Mn and Fe, as well as their accumulation rates, were comparable to our previous results from the desert of Saudi Arabia. There was a moderate dependence of the Mn areal density on the inclination of the rock surfaces, but no relationship to its cardinal orientation. We attempted to use the degree of varnish regrowth on the rock art surfaces as an estimate of their age. While an absolute dating of the petroglyphs was not possible because of the lack of suitable calibration surfaces and a considerable amount of variability, the measured degree of varnish regrowth on the various petroglyphs was consistent with chronologies based on archeological and other archaeometric techniques. In particular, our results suggest that rock art creation in the study area continued over an extended period of time, possibly starting around the Pleistocene/Holocene transition and extending into the last few centuries.


Assuntos
Argila/química , Hidróxidos/análise , Ferro/análise , Manganês/análise , California , Meio Ambiente , Monitoramento Ambiental , Espectrometria de Massas , Metais Terras Raras/análise , Espectrometria por Raios X , Propriedades de Superfície , Erupções Vulcânicas , Ítrio/análise
7.
Ecotoxicol Environ Saf ; 204: 111097, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32784016

RESUMO

Iron (hydr)oxide-natural organic matter (NOM) colloids, the dominant components of soil, usually occur in varied circumstances and may affect Hg transport and fate in soil. This study aims to reveal the Hg binding to preformed composites rather than only focusing on Hg retention by iron (hydr)oxides in the presence of NOM. Ferrihydrite-humic acid (FH-HA) is chosen as a representative composite, and the effect of the complexation method and FH morphology on Hg binding to various composites is evaluated. Three types of composites are developed: a dense coprecipitated composite (p-d-f), a gel-like adsorbed composite (a-g-f) and a dense adsorbed (a-d-f) composite. Batch sorption and stirred-flow kinetic tests together with surface property analysis and modern spectral analyses are carried out to explore the binding behavior of Hg to the three composites and clarify the interactions in the ternary systems of FH-HA-Hg. The results show that the Hg sorption isotherms all fit well with the Langmuir model, and the maximum sorption capacities follow the order a-g-f> a-d-f > p-d-f, implying that the adsorbed composite is more favorable than the coprecipitated composite for Hg binding and a gel morphology is more beneficial than a dense morphology. The stirred-flow experiments show that the adsorbed composite has a small advantage in Hg sorption compared to the coprecipitated composite and that the gel-like composite can adsorb more Hg at a faster rate than the dense composite. Both FH and HA participate in Hg sorption, and FH-HA-Hg complexes are speculated to form. These findings are helpful to better understand the mobility and fate of Hg in soils, as well as the associated dynamic model for predicting Hg behavior in the environment where the iron (hydr) oxide-NOM composites are pre-existed.


Assuntos
Mercúrio/química , Adsorção , Coloides , Compostos Férricos/química , Substâncias Húmicas/análise , Ferro/análise , Cinética , Mercúrio/análise , Compostos Orgânicos/química , Óxidos/química , Solo/química , Propriedades de Superfície
8.
Life Sci ; 259: 118356, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32861798

RESUMO

Curculigoside (CUR) is natural ingredient from Curculigo orchioides Gaertn with multiple biological activities. However, whether CUR protects from ulcerative colitis (UC) and underlying mechanisms are unclear. Herein, mice challenged with dextran sulfate sodium (DSS) were established and administrated with CUR for 7 days. Then histological pathologies and ferroptosis regulators were determined in vivo. The ferroptotic IEC-6 cells were prepared to investigate the underlying mechanism of CUR. Results showed that CUR inhibited the disease activity index, histological damage and cell death in mice with colitis. We also found that ferroptosis was induced in mice with colitis, as evidenced by iron overload, GSH depletion, ROS and MDA production, accompanied by decreased expression of SOD and GPX4. CUR treatment significantly reversed these alterations of ferroptotic features in DSS-induced mice. Furthermore, similar effects of CUR on ferroptosis were observed in IEC-6 cells under the combined treatment of H2O2 and iron chloride hexahydrate. Interestingly, we found that CUR could increase the selenium sensitivity and promote GPX4 transcription level in IEC-6 cells. Knockdown of GPX4 significantly blocked the protective effects of CUR on cell death, GSH and MDA contents as well as LDH activity in ferroptotic IEC-6 cells. Taken together, these findings suggest that CUR protects against ferroptosis in UC by the induction of GPX4, which presents a potential agent for UC treatment.


Assuntos
Benzoatos/uso terapêutico , Colite Ulcerativa/tratamento farmacológico , Ferroptose/efeitos dos fármacos , Glucosídeos/uso terapêutico , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Animais , Western Blotting , Linhagem Celular , Colite Ulcerativa/metabolismo , Colite Ulcerativa/patologia , Colo/química , Colo/efeitos dos fármacos , Colo/metabolismo , Colo/patologia , Ferro/análise , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Reação em Cadeia da Polimerase em Tempo Real
9.
Chemosphere ; 260: 127533, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32679374

RESUMO

In recent decades, nanoscale zero valent iron (nZVI) has been found to be a promising approach for heavy metal remediation. This study is the first report highlighting the role of nZVI to ameliorate Cadmium (Cd) stress in rice along with its effects in expressions of transporter genes, agronomic parameters and grain nutrient status. Initially, 3 concentration of Cd (10, 50, 250 µM) and nZVI (50, 100, 200 mg L-1) were selected. PCA analysis based on growth parameters, photosynthetic pigment contents and lipid peroxidation rate confirmed that 100 mg L-1 nZVI was most suitable for remediation of 10 µM Cd. It was evident that, nZVI can alleviate Cd-induced toxic effects by enhancing antioxidant defense mechanisms and other physiological processes in plants. nZVI treated rice seedlings also showed upregulation of phytochelatins which aided in Cd chelation within vacuoles. Study of root morphology with scanning electron microscopy and ROS imaging with confocal microscopy confirmed that nZVI could alleviate oxidative stress due to Cd uptake. In nZVI treated rice seedlings, gene expressions of iron (Fe) transporters (like, IRT1,IRT2,YSL2,YSL15) which are responsible for both Fe and Cd uptake were significantly down-regulated whereas, OsVIT1 and OsCAX4 genes were over expressed which lead to sequestration of Cd in vacuoles. Cd localization assay with leadmium proved that Cd translocation was reduced with nZVI treatment. To further validate our findings a pot experiment was carried out where it was found that nZVI could immobilize Cd in soil prevented accumulation of Cd in rice grains in addition to improving yield.


Assuntos
Cádmio/química , Poluentes do Solo/química , Antioxidantes/metabolismo , Transporte Biológico , Cádmio/análise , Grão Comestível/química , Ferro/análise , Metais Pesados/análise , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fitoquelatinas/metabolismo , Plântula/efeitos dos fármacos , Solo , Poluentes do Solo/análise
10.
Water Res ; 182: 116003, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32721701

RESUMO

The development of low dissolved oxygen (DO) concentrations in the hypolimnion of drinking water reservoirs during thermal stratification can lead to the reduction of oxidized, insoluble iron (Fe) and manganese (Mn) in sediments to soluble forms, which are then released into the water column. As metals degrade drinking water quality, robust measurements of metal fluxes under changing oxygen conditions are critical for optimizing water treatment. In this study, we conducted benthic flux chamber experiments in summer 2018 to directly quantify Fe and Mn fluxes at the sediment-water interface under different DO and redox conditions of a eutrophic drinking water reservoir with an oxygenation system (Falling Creek Reservoir, Vinton, VA, USA). Throughout the experiments, we monitored DO, oxidation-reduction potential (ORP), water temperature, and pH in the chambers and compared the metal fluxes in the chambers with time-series of fluxes calculated using a hypolimnetic mass balance method. Our results showed that metal fluxes were highly variable during the monitoring period and were sensitive to redox conditions in the water column at the sediment-water interface. The time-series changes in fluxes and relationship to redox conditions are suggestive of "hot moments", short time periods of intense biogeochemical cycling. Although the metal concentrations and fluxes are specific to this site, the approaches for examining relationships between metals, oxygen concentrations and overall redox conditions can be applied by water utilities to improve water quality management of Fe and Mn.


Assuntos
Água Potável , Poluentes Químicos da Água/análise , Purificação da Água , Monitoramento Ambiental , Sedimentos Geológicos , Ferro/análise , Manganês/análise
11.
Bone Joint J ; 102-B(7_Supple_B): 116-121, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32600200

RESUMO

AIMS: This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. METHODS: Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment. RESULTS: On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant increase in aluminum (p < 0.001) among all groups compared with medium only. CONCLUSION: These results indicated that macrophages were able to attach to and affect the oxide surface of stainless steel and titanium alloy discs. Cite this article: Bone Joint J 2020;102-B(7 Supple B):116-121.


Assuntos
Prótese Articular , Macrófagos/química , Aço Inoxidável , Titânio , Vitálio , Ligas , Animais , Sobrevivência Celular , Cromo/análise , Meios de Cultura , Íons , Ferro/análise , Camundongos , Microscopia Eletrônica de Varredura , Níquel/análise , Óxido Nítrico/análise
12.
Nat Commun ; 11(1): 3273, 2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32601301

RESUMO

Restoration of coronary blood flow after a heart attack can cause reperfusion injury potentially leading to impaired cardiac function, adverse tissue remodeling and heart failure. Iron is an essential biometal that may have a pathologic role in this process. There is a clinical need for a precise noninvasive method to detect iron for risk stratification of patients and therapy evaluation. Here, we report that magnetic susceptibility imaging in a large animal model shows an infarct paramagnetic shift associated with duration of coronary artery occlusion and the presence of iron. Iron validation techniques used include histology, immunohistochemistry, spectrometry and spectroscopy. Further mRNA analysis shows upregulation of ferritin and heme oxygenase. While conventional imaging corroborates the findings of iron deposition, magnetic susceptibility imaging has improved sensitivity to iron and mitigates confounding factors such as edema and fibrosis. Myocardial infarction patients receiving reperfusion therapy show magnetic susceptibility changes associated with hypokinetic myocardial wall motion and microvascular obstruction, demonstrating potential for clinical translation.


Assuntos
Ferro/análise , Traumatismo por Reperfusão Miocárdica/diagnóstico por imagem , Idoso , Animais , Estudos Transversais , Feminino , Ferritinas/metabolismo , Heme Oxigenase (Desciclizante)/metabolismo , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/patologia , Cicatrização
13.
Ecotoxicol Environ Saf ; 203: 110995, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678763

RESUMO

In the present study, silver (Ag) atoms were chemically deposited on γ-alumina (Al2O3) nanospheres to be further functionalized with trithiocyanuric acid (TTC). The result was Al2O3@Ag@TTC composites, which were used for the selective extraction and preconcentration of Fe (III) and Pb (II) ions in seawater and river water samples. TTC is a potent scavenger of heavy metal ions with multiple nitrogen- and sulfur-containing functional groups. The concentrations of analytes were determined by flame atomic absorption spectrometry, and the structure of the synthetic adsorbent was characterized by spectral and microscopic techniques. Furthermore, the fundamental parameters influencing the extraction and desorption of the target ions were evaluated. Under optimized conditions, the calibration curve was linear in the range of 10-100 ng mL-1 for both analytes. The detection limits of the proposed method for Fe (III) and Pb (II) ions were 1.5 ng mL-1 and 0.8 ng mL-1, respectively, with a relative standard deviation of less than 6.1% (n = 7). Moreover, the proposed method tolerated salinities of up to 50.0 g L-1 without exhibiting any decrease in selectivity or recovery. The developed method was successfully applied to extract Fe (III) and Pb (II) ions from seawater and river water samples. The extraction recovery rates of the spiked ions were at least 93% for Fe (III) and 97 % for Pb (II).


Assuntos
Óxido de Alumínio/química , Ferro/análise , Chumbo/análise , Nanoconjugados/química , Prata/química , Triazinas/química , Poluentes Químicos da Água/análise , Água Doce/química , Concentração de Íons de Hidrogênio , Íons , Água do Mar/química , Extração em Fase Sólida/métodos
14.
Environ Pollut ; 264: 114789, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32559882

RESUMO

Perfluorohexane sulfonate (PFHxS) has been newly recommended to be added into the Stockholm Convention on persistent organic pollutants (POPs). As one of the major perfluoroalkyl pollutants, its long half-time in human serum and neurotoxicity are cause for significant concern. Although mechanochemical degradation has been evaluated as a promising ecofriendly technology to treat pollutants, the extraordinary stability of poly- and perfluoroalkyl substances (PFASs) raises harsh requirements for co-milling reagents. In the present study, zero-valent iron (ZVI) and ferrate(VI) were for the first time used as the co-milling reagents to degrade PFHxS. When ZVI and ferrate(VI) were used alone, both the degradation and defluorination efficiencies were low. However, after milling at the optimum ratio (ferrate(VI):ZVI = 1:2) for 4 h, the synergistic effect of ZVI and ferrate(VI) resulted in almost complete degradation (100%) and defluorination (95%). Two points can account for this excellent performance: (1) the mechanochemical energy input in the system initiates and prominently promotes related reactions; and (2) the active species generated from the reactions among ZVI, ferrate(VI) and other high-valent iron species will accelerate the process of electron transfer. The sulfonate group comprises the favorable attack sites, as corroborated by both the identified intermediates and quantum chemical calculations. The homolysis of the C-S bond is not only the triggering step, but also the rate-limiting step. In summary, the present work confirms the feasibility and underlying mechanism of the ZVI-ferrate(VI) co-milling system to defluorinate PFHxS, which might be a promising technology to treat PFASs in solid wastes.


Assuntos
Fluorcarbonetos , Poluentes Químicos da Água/análise , Ferro/análise , Oxirredução
15.
Environ Sci Pollut Res Int ; 27(28): 34927-34940, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32577983

RESUMO

Tianbao reservoir in southern China (surrounded by Eucalyptus plantation) serves as a source of drinking water for the inhabitants. However, the reservoir water experiences black water (BW) of which the cause remains unclear. In this study, field observation and simulated laboratory experiment were conducted to understand the cause of the BW. The diffusive gradient in thin-film (DGT) device monitored the spatial changes in concentration of iron (Fe2+), manganese (Mn2+), sulfide (S2-), and dissolved organic carbon (DOC) at the SWI. The planar optode (PO) showed that hypoxia contributed immensely to the high positive fluxes Fe2+, Mn2+, and S2- measured, which co-precipitated to form black materials (FeS and MnS) at the SWI. The co-precipitation between Fe-S and Mn-S was supported by their significant positive correlation (Fe-S: r > 0.05, p < 0.05, Mn-S: r > 0.2, p < 0.05). Significant reduction (p < 0.05) in tannins concentration from November (strong thermal stratification) to December (weak thermal stratification) indicated that Fe2+ and tannins reacted during the mixing of reservoir water in December due to weak stratification. The simulated experiment confirmed that fresh Eucalyptus leaves produces a significant (p < 0.05) amount of tannins during hypoxia and reacts with Fe2+ to produce black water. A high positive correlation (r > 0.8) between Fe2+ and DOC demonstrated that Fe2+ and DOC combined and contributed to the reservoir water blackening. The study provides a better understanding on the impact of Eucalyptus plantation on water quality and provide guidance for scientific planting of Eucalyptus plantation in reservoir basins in southern China to ensure safe drinking water.


Assuntos
Eucalyptus , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Ferro/análise , Água
16.
PLoS One ; 15(6): e0234395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32525930

RESUMO

As rice is an important staple food globally, research for development and enhancement of its nutritional value it is an imperative task. Identification of nutrient enriched rice germplasm and exploiting them for breeding programme is the easiest way to develop better quality rice. In this study, we analyzed 113 aromatic rice germplasm in order to identify quantitative trait loci (QTL) underpinning nutrition components and determined by measuring the normal frequency distribution for Fe, Zn, amylose, and protein content in those rice germplasm. Comparatively, the germplasm Radhuni pagal, Kalobakri, Thakurbhog (26.6 ppm) and Hatisail exhibited the highest mean values for Fe (16.9 ppm), Zn (34.1 ppm), amylose (26.6 ppm) and protein content (11.0 ppm), respectively. Moreover, a significant linear relationship (R2 = 0.693) was observed between Fe and Zn contents. Cluster analysis based on Mahalanobis D2 distances revealed four major clusters of 113 rice germplasm, with cluster III containing a maximum 37 germplasm and a maximum inter-cluster distance between clusters III and IV. The 45 polymorphic SSRs and four trait associations exhibited eight significant quantitative trait loci (QTL) located on eight different chromosomes using composite interval mapping (CIM). The highly significant QTL (variance 7.89%, LOD 2.02) for protein content (QTL.pro.1) was observed on chromosome 1 at 94.9cM position. Also, four QTLs for amylose content were observed with the highly significant QTL.amy.8 located on chromosome 8 exhibiting 7.2% variance with LOD 1.83. Only one QTL (QTL.Fe.9) for Fe content was located on chromosome 9 (LOD 1.24), and two (QTL.Zn.4 and QTL.Zn.5) for Zn on chromosome 4 (LOD 1.71) and 5 (LOD 1.18), respectively. Overall, germplasm from clusters III and IV might offer higher heterotic response with the identified QTLs playing a significant role in any rice biofortification breeding program and released with development of new varieties.


Assuntos
Oryza/genética , Locos de Características Quantitativas , Amilose/análise , Biofortificação/métodos , Produtos Agrícolas/química , Produtos Agrícolas/classificação , Produtos Agrícolas/genética , Alimentos Fortificados/análise , Genes de Plantas , Marcadores Genéticos , Ferro/análise , Valor Nutritivo , Oryza/química , Oryza/classificação , Fenótipo , Melhoramento Vegetal/métodos , Proteínas de Vegetais Comestíveis/análise , Análise de Regressão , Sementes/química , Sementes/genética , Zinco/análise
17.
Chemosphere ; 259: 127398, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593818

RESUMO

Arsenic endosmosis causes a severe threat to human health within the developing countries. This study assessed the levels of geogenic arsenic and other heavy metals affecting the release of As in the aquifers within the drinking water sources in Bhojpur district of Bihar, India. Eighteen water samples were collected in triplicates from hand-dug wells in six neighboring villages in proximity to the River Ganga namely Bakhorapur, Gaziapur, Parasrampur (or Kanhachhapara), Saraiya, Paiga and Gundiinin. The physicochemical parameters, ionic content and heavy metal analysis of the collected water samples indicated the region to be highly contaminated with arsenic, zinc, manganese and iron. The arsenic and iron concentration ranged between 24.3 and 168.07 µg/L and 0.17-1.16 mg/L respectively, indicating the excessive withdrawal of groundwater for domestic and irrigation purposes with a significant correlation between both the metals. Elevated concentration of zinc in the region attributed to the excessive application of chemical fertilizers and pesticides. Concentration of manganese was also in the higher range of 0.05-1.15 mg/L, primarily due to the urbanized industrial activities. Human health risk assessment within two population groups in the region indicated that the overall water quality is slightly contaminated but the risk associated with it is low. Water Quality Index ranged from 29 to 48, signifying the water quality to be poor. Residual sodium carbonate values indicated that few water sample sources are not suitable for irrigation purposes whereas, sodium adsorption ratio (SAR) values were within the acceptable limits to be used for irrigation.


Assuntos
Monitoramento Ambiental , Água Subterrânea/química , Poluentes Químicos da Água/análise , Arsênico/análise , Água Potável/química , Humanos , Índia , Ferro/análise , Manganês/análise , Metais Pesados/análise , Medição de Risco , Rios , Qualidade da Água , Poços de Água
18.
Chemosphere ; 251: 126388, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443223

RESUMO

Over the last few decades, the global pollution of surface and groundwater poses a serious threat not only to human beings but also towards aquatic lives due to the presence of emerging contaminants. Among the others, the presence of arsenic, fluoride, and iron are considered as the most common toxic pollutants in water bodies. The emergence of metal organic frameworks (MOFs) with high porosity and surface area is represented as significant inclusion into the era of entrapping contaminants present in drinking water. In the present review article, an in-depth insight is provided on the recent developments in the removal of arsenic, fluoride, and iron from drinking water using MOFs. Various aspects related to the synthesis, latest technologies adopted for the modifications in the synthesis process and advanced applications of MOFs for the removal of such contaminants are explicitly discussed. A detailed insight was provided to understand the mechanism of various interactions of MOFs with arsenic and fluoride. With respect to arsenic, fluoride, and iron removal the ultrastructural morphology of MOFs is assessed based on different molecular arrangements. Further, commercial aspects of various MOFs are presented in order to highlight the process feasibility. Finally, various perspectives and challenges involved in process scale up are comprehensively narrated with an aspiration of futuristic developments. The paper will be beneficial to the readers for acquiring a piece of in-depth knowledge on MOFs and its various synthesis approaches along with remarkable achievements for the removal of arsenic, fluoride, and iron from contaminated drinking water.


Assuntos
Arsênico/química , Água Potável/química , Fluoretos/química , Ferro/química , Poluentes Químicos da Água/química , Arsênico/análise , Poluentes Ambientais , Água Subterrânea/química , Humanos , Ferro/análise , Estruturas Metalorgânicas , Poluentes Químicos da Água/análise , Poluição da Água , Purificação da Água/métodos
19.
J Vis Exp ; (159)2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32421003

RESUMO

Dyshomeostasis of iron metabolism is accounted in the pathophysiological framework of numerous diseases, including cancer and several neurodegenerative conditions. Excessive iron results in free redox-active Fe(II) and can cause devastating effects within the cell like oxidative stress (OS) and death by lipid peroxidation known as ferroptosis (FPT). Therefore, quantitative measurements of ferrous (Fe(II)) and ferric (Fe(III)) iron rather than total Fe-determination is the key for closer insight into these detrimental processes. Since Fe(II)/(III) determinations can be hampered by fast redox-state shifts and low concentrations in relevant samples, like cerebrospinal fluid (CSF), methods should be available that analyze quickly and provide low limits of quantification (LOQ). Capillary electrophoresis (CE) offers the advantage of fast Fe(II)/Fe(III) separation and works without a stationary phase, which could interfere with the redox balance or cause analyte sticking. CE combined with inductively coupled plasma mass spectrometry (ICP-MS) as a detector offers further improvement of detection sensitivity and selectivity. The presented method uses 20 mM HCl as a background electrolyte and a voltage of +25 kV. Peak shapes and concentration detection limits are improved by conductivity-pH-stacking. For reduction of 56[ArO]+, ICP-MS was operated in the dynamic reaction cell (DRC) mode with NH3 as a reaction gas. The method achieves a limit of detection (LOD) of 3 µg/L. Due to stacking, higher injection volumes were possible without hampering separation but improving LOD. Calibrations related to peak area were linear up to 150 µg/L. Measurement precision was 2.2% (Fe(III)) to 3.5% (Fe(II)). Migration time precision was <3% for both species, determined in 1:2 diluted lysates of human neuroblastoma (SH-SY5Y) cells. Recovery experiments with standard addition revealed accuracy of 97% Fe(III) and 105 % Fe(II). In real-life bio-samples like CSF, migration time can vary according to varying conductivity (i.e., salinity). Thus, peak identification is confirmed by standard addition.


Assuntos
Eletrólitos/metabolismo , Eletroforese Capilar/métodos , Ferro/análise , Espectrometria de Massas/métodos , Neuroblastoma/metabolismo , Humanos , Oxirredução , Células Tumorais Cultivadas
20.
Environ Pollut ; 264: 114769, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32428816

RESUMO

Soluble iron (FeS) in aerosols contributes to free oxygen radical generation with implications for human health, and potentially catalyzes sulfur dioxide oxidation. It is also an important external source of micronutrients for ocean ecosystems. However, factors controlling FeS concentration and its contribution to total iron (FeT) in aerosols remain poorly understand. Here, FeS and FeT in PM2.5 was studied at four urban sites in eastern China from 21 to 31 December, 2017. Average FeT (869-1490 ng m-3) and FeS (24-68 ng m-3) concentrations were higher in northern than southern China cities, but Fe solubility (%FeS, 2.7-5.0%) showed no spatial pattern. Correlation analyses suggested %FeS was strongly correlated with FeS and PM2.5 instead of FeT concentrations. Individual particle observations confirmed that more than 65% of nano-sized Fe-containing particles were internally mixed with sulfates and nitrates. Furthermore, there was a high correlation between sulfates or nitrates/FeT molar ratio and %FeS. We also found that the sulfates/nitrates had weaker effects on %FeS at RH < 50% than at RH > 50%, suggesting RH as indirect factor can influence %FeS in PM2.5. These results suggest an important role of chemical processing in enhancing %FeS in the polluted atmosphere.


Assuntos
Poluentes Atmosféricos/análise , Aerossóis/análise , China , Cidades , Ecossistema , Monitoramento Ambiental , Humanos , Ferro/análise , Nitratos/análise , Material Particulado/análise , Solubilidade , Sulfatos/análise
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