Gross Chemical Fractionation of Organic Matter

2016 ◽  
pp. 1409-1421 ◽  
Author(s):  
F. J. Stevenson
Keyword(s):  
Organic Matter ◽  
Chemical Fractionation

scholarly journals Molecular characterization of an end-residue of humeomics applied to a soil humic acid

RSC Advances ◽  
2014 ◽  
Vol 4 (45) ◽  
pp. 23658-23665 ◽  
Author(s):  
A. Nebbioso ◽  
A. Piccolo ◽  
M. Lamshöft ◽  
M. Spiteller
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Molecular Characterization ◽  
Natural Organic Matter ◽  
Molecular Composition ◽  
Chemical Fractionation ◽  
Soil Humic Acid

Humeomics encompasses step-wise chemical fractionation and instrumental determination to fully characterize the heterogeneous molecular composition of natural organic matter.

Chemical fractionation of organic matter and organic phosphorus extractions from freshwater lake sediment

2020 ◽  
Vol 1130 ◽  
pp. 29-38 ◽  
Author(s):  
M.R. Kurek ◽  
M. Harir ◽  
J.T. Shukle ◽  
A.W. Schroth ◽  
P. Schmitt-Kopplin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Lake Sediment ◽  
Organic Phosphorus ◽  
Freshwater Lake ◽  
Chemical Fractionation

scholarly journals Lead and zinc in the structure of organic and mineral soil components

2013 ◽  
Vol 37 (2) ◽  
pp. 438-449 ◽  
Author(s):  
Larissa Kummer ◽  
Vander de Freitas Melo ◽  
Yara Jurema Barros
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Mineral Soil ◽  
Complete Removal ◽  
Extraction Methods ◽  
Chemical Fractionation ◽  
Isomorphic Substitution ◽  
Fe Oxides ◽  
Mineral Phases ◽  
Mineral Associations

In addition to the more reactive forms, metals can occur in the structure of minerals, and the sum of all these forms defines their total contents in different soil fractions. The isomorphic substitution of heavy metals for example alters the dimensions of the unit cell and mineral size. This study proposed a method of chemical fractionation of heavy metals, using more powerful extraction methods, to remove the organic and different mineral phases completely. Soil samples were taken from eight soil profiles (0-10, 10-20 and 20-40 cm) in a Pb mining and metallurgy area in Adrianópolis, Paraná, Brazil. The Pb and Zn concentrations were determined in the following fractions (complete phase removal in each sequential extraction): exchangeable; carbonates; organic matter; amorphous and crystalline Fe oxides; Al oxide, amorphous aluminosilicates and kaolinite; and residual fractions. The complete removal of organic matter and mineral phases in sequential extractions resulted in low participation of residual forms of Pb and Zn in the total concentrations of these metals in the soils: there was lower association of metals with primary and 2:1 minerals and refractory oxides. The powerful methods used here allow an identification of the complete metal-mineral associations, such as the occurrence of Pb and Zn in the structure of the minerals. The higher incidence of Zn than Pb in the structure of Fe oxides, due to isomorphic substitution, was attributed to a smaller difference between the ionic radius of Zn2+ and Fe3+.

scholarly journals Fractions of soil organic matter in the vineyards of altitude regions in Santa Catarina

2017 ◽  
Vol 38 (4) ◽  
pp. 1799
Author(s):  
Denilson Dortzbach ◽  
Shirlei Almeida Assunção ◽  
Marcos Gervasio Pereira ◽  
Eduardo Carvalho da Silva Neto
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Carbon Stock ◽  
Chemical Fractionation ◽  
Acid Fraction ◽  
Carbon Management ◽  
Forested Areas ◽  
Carbon Management Index ◽  
Humin Fraction ◽  
Region Ii

The implementation of agricultural systems such as viticulture can quantitatively and qualitatively affect the contents of soil organic matter (SOM). These changes may modify the edaphic features of the soil as well as the soil quality. The objective of this study was to evaluate the chemical and physical fraction of SOMand to analyze changes in the carbon stock and C management index in areas of implanted vineyards in altitude regions of Santa Catarina. Four regions were selected: Region I (Urubici); Region II (San Joaquim); Region III (Campos Novos) and Region IV (Água Doce). In each region, we selected vineyards implanted between 2001 and 2005 as well as surrounding forested areas. Disturbed and undisturbed samples were collected from the 0-5, 5-10, and 10-20 cm layers of the soil. Samples were prepared in the laboratory to obtain air-dried soft soil, which was then used for the analysis of several parameters, namely total organic carbon (TOC), carbon stock,and chemical fractionation of the soil. The chemical fractionation was then used to determine carbon content in the fulvic acid fraction (C-FAF), humic acid fraction (C-HAF), and humin fraction (C-HUM). We also analyzed particle size, quantified the levels of particulate carbon (COp) and carbon associated with clay and silt (COam), and calculated the carbon management index (CMI). We evaluated normality and homogeneity for all data. The results were evaluated with an analysis of variance and subsequent F-test. Mean values were compared using a 5% Student’s t-test and subsequently submitted to a Tukey’s test. The highest TOC levels were observed in Region II in the 0-5 cm layer in both vineyard and forested areas. Vineyard areas exhibited lower values of TOC, Cop, and COam compared to forested areas indicating that the management adopted in these areas contributed to the reduction of these fractions. Forested areas exhibited a higher proportion of Cop compared to vineyard areas. The humin fraction represented the largest portion of the TOC and comprised the highest values in both forested and vineyard areas. The carbon management index indicated a low contribution of vineyard areas or a reduction in carbon storage in their soils.

An adapted sequential chemical fractionation coupled with UV and fluorescence spectroscopy for calcareous soil organic matter study after compost amendment

2016 ◽  
Vol 124 ◽  
pp. 139-148 ◽  
Author(s):  
Olsen Rainness Mouloubou ◽  
Pascale Prudent ◽  
Stéphane Mounier ◽  
Jean-Luc Boudenne ◽  
Madi Guirema Abaker ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Fluorescence Spectroscopy ◽  
Calcareous Soil ◽  
Chemical Fractionation ◽  
Compost Amendment

Investigation on organic matter-mineral interaction by confocal multispectral and time-resolved microscopy

2020 ◽  
Author(s):  
Francisco E G Guimaraes ◽  
Carla P Morais ◽  
Amanda Tadini ◽  
Mauricio Falvo ◽  
Odemir Bruno ◽  
...  
Keyword(s):  
Organic Matter ◽  
Glass Surface ◽  
Crystal Surface ◽  
Visible Region ◽  
Life Time ◽  
Direct Access ◽  
Chemical Fractionation ◽  
Molecular Aggregates ◽  
Mineral Fraction ◽  
Molecular Stacking

<p>Organic matter makes up less than 5% of soil and sediment and is often linked to the particulate mineral fraction, forming an organo-mineral microsystem that certainly contributes to its stability in the natural environment. However, most of the techniques used to study and quantify organic matter necessarily require the separation of the organic phase from the mineral phase by chemical or physical extraction and, subsequently fractionation methods that destroy and/or degrade the original aggregate morphological structure. The present work demonstrates that Scanning Confocal Microscopy (MC) can be used as a non-destructive fluorescence technique capable of characterizing organic matter (OM) interacting with the surface of the mineral fraction in soils and sediments without prior sample preparation and use of extraction or chemical fractionation of its components. Organic matter (OM) interacts with the mineral surface through molecular stacking in the form of stable molecular aggregates. Besides that, aggregate states also favor energy transfer processes between aggregated molecules which strongly affects the dynamics of excited state producing spectral shifts to the red and changes in life-time that can be correlated to aggregate morphology and to molecular amount deposited on the surface. These features confer a high spectral and intensity contrast of the confocal images. Here, infrared 2-photon (2P) excitation proved to be adequate to selectively excite OM aggregate states in the visible region between 400 and 700 nm, which allows a direct access to the fundamental aspects of the organic matter-mineral interactions.</p><p>We will show that the use of confocal methodologies, together with image analysis, provide helpful tools to understand the complex OM interactions at a molecular level. Here, we studied the interaction of OM with sodium bicarbonate and sodium hydroxide surfaces that form fractal crystals. When a drop of water containing both soil and solubilized bicarbonate or hydroxide salts is dried on a glass surface, dendritic-type salt crystals are first formed on the glass surface within the water droplet. In a second step of the droplet drying process, suspended organic molecules deposit on the surface of these fractal crystals. We will show that the morphology and molecular packaging substantially change spectral and life-time properties which strongly depend on the amount of OM on the crystal surface. Special features can be obtained from linear unmixing of spectral images using 1P and 2P excitation at 375 nm and 750 nm respectively for OM interacting with powder bicarbonate. Therefore, molecular aggregates of interacting fluorescence-emitting species can be used to characterize OM regarding the morphological, molecular structure and interactions with inorganic surfaces. These properties determine the stability of the original OM packing and the limits for the molecular stacking on different active surfaces in nature.</p>

Hg distribution and speciation in Antarctic soils of the Fildes and Ardley peninsulas, King George Island

2012 ◽  
Vol 24 (4) ◽  
pp. 395-407 ◽  
Author(s):  
Renato Pereira De Andrade ◽  
Roberto Ferreira Machado Michel ◽  
Carlos Ernerto Gonçalves Reynaud Schaefer ◽  
Felipe Nogueira Bello Simas ◽  
Cláudia Carvalhinho Windmöller
Keyword(s):  
Organic Matter ◽  
Solid Phase ◽  
Soil Depth ◽  
Close Correlation ◽  
Chemical Fractionation ◽  
King George Island ◽  
Maritime Antarctic ◽  
Antarctic Soils ◽  
Ornithogenic Soils ◽  
The Antarctic

AbstractData on the content and speciation of mercury (Hg) in the soils of Antarctica are scarce and vary greatly between the regions studied, but overall Hg concentrations found were generally very low. We investigated the Hg quantity and speciation by solid-phase Hg pyrolysis and chemical fractionation in selected maritime Antarctic soils, comparing ornithogenic and non-ornithogenic areas of the Fildes and Ardley peninsulas of King George Island. The total Hg contents ranged from 4.3–256 ng g-1, and values for ornithogenic soils were the highest recorded for Antarctic soils. A close correlation between Hg and organic matter was observed in the ornithogenic soils, with levels decreasing with depth. In the non-ornithogenic soils, a correlation between Hg content and soil depth was also observed, but the values were found to increase with depth. Thermograms showed that all Hg was in the 2+ oxidation state and was predominantly linked to organic matter, corroborating the chemical fractionation results for the ornithogenic soils. These results show the need for further refined studies about the interactions of Hg with organic matter in order to better understand the biogeochemistry of this metal in the Antarctic environment.

scholarly journals Fractionation of heavy metals in yellow latosol cultivated with vegetables

2018 ◽  
Vol 39 (5) ◽  
pp. 1921
Author(s):  
Laércio Santos Silva ◽  
Izabel Cristina de Luna Galindo ◽  
Vinícius Augusto Filla ◽  
Romário Pimenta Gomes ◽  
Milton César Costa Campos ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Matter ◽  
Heavy Metal Contamination ◽  
Soil Samples ◽  
Chemical Fractionation ◽  
Human Consumption ◽  
Native Forest ◽  
Metal Levels ◽  
Toxic Potential

Sequential extraction or chemical fractionation of heavy metals allows inferences to be made about their origin, occurrence, bioavailability, toxic potential and environmental contamination. Thus, the present study aimed to assess the distribution of Cu, Mn, Ni, Pb and Zn among the different soil fractions and landscape compartments of a yellow latosol cultivated with vegetables. Soil samples were collected from five areas cultivated with tomato (Lycopersicon esculentum, Mill.), lettuce (Lactuca sativa), chili pepper (Capsicum annuum L.) and chard (Beta vulgaris L.) in different slope positions (upper, middle, lower), and four reference areas (native forest), at a depth of 0.00 - 0.20 m. Heavy metal levels were also assessed in water used to irrigate the crops and for human consumption by collecting 200 ml of water samples from reservoirs. The soil samples were sequentially fractionated to quantify the concentrations of adsorbed Cu, Mn, Ni, Pb and Zn in the exchangeable (EF), organic matter (OF), amorphous and crystalline iron oxide fractions (AFeOx and CFeOx). Landscape position only interfered significantly in heavy metal adsorption in the soil for Cu and Ni associated with CFeOx and Zn bound to the EF in the farming areas. The highest Cu, Ni, Pb and Zn levels were found in the fractions with less stable chemical bonds (bound to organic matter), in addition to a strong affinity between Cu, Zn and Mn and the oxide fractions (AFeOx + CFeOx). The low affinity of Pb and Ni for the AFeOx and CFeOx fractions indicates greater contamination potential for the water reservoirs. In the short term, organic matter is the main source of remediation for heavy metal contamination in soil, making it important to adopt conservation practices aimed at reducing OM losses.

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