Evaluation of a sequential extraction procedure for the fractionation of amorphous iron and manganese oxides and organic matter in soils

Abstract The content of trace elements in soils varies widely and their mobility and availability depends not only on the total content but also on the form of in which these elements occur. The aim of this study was to determine the total content of nickel, lead, zinc and copper in soils used for agriculture, and assess the mobility and phytoavailability of these metals against a background of physical and chemical properties of these soils. In samples taken from three soil profiles (Phaeozem and 2 Fluvisols) the contents of Ni, Pb, Zn and Cu were determined using atomic absorption spectroscopy in the solutions obtained according to the protocol of modified BCR sequential extraction procedure supplemented with aqua regia digestion. The total content of the analyzed metals in most cases corresponded to the natural values, often not exceeding the geochemical background level. It was only in the one profile of the Fluvisols (Endogleyic Fluvisol) that a higher concentration of zinc and lead was noticed (especially in the surface horizon), slightly exceeding the legal limit. Among the studied metals the lowest phytoavailability was characterized by copper (exchangeable forms on average 4.73% of the total), and the highest by zinc (11.49%). Nickel was the most permanently bound with soil solid phase, and its content in the residual fraction reached 84.46% of the total. Approximately a half of the total lead content was determined as a fraction bound with iron and manganese oxides, while in the case of this metal a significant role in binding of this metal was playing organic matter (fraction bound with organic matter and sulphides - an average of 27.5%). Significant role in the binding of all investigated metals was credited to iron and manganese compounds.

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Selenium Fractionation and Speciation in Paddy Soils and Accumulation in Rice Under Field Conditions in Jinhua Zhejinang Province, China

E3S Web of Conferences ◽

10.1051/e3sconf/202014302014 ◽

2020 ◽

Vol 143 ◽

pp. 02014

Author(s):

Yixian Shao ◽

Bangting Xie ◽

Mengqi Li ◽

Xiang Zhang ◽

Hua Xiao

Keyword(s):

Organic Matter ◽

Sequential Extraction ◽

Manganese Oxide ◽

Humic Acids ◽

Indirect Effect ◽

Agricultural Soil ◽

Extraction Procedure ◽

Zhejiang Province ◽

Tissue Samples ◽

Iron And Manganese

Soils, as well as paddy tissue samples, were collected in the Se-rich area of Jinhua County, Zhejiang Province, China. Sequential extraction procedure was used for selenium (Se) fractionation, including soluble Se, exchangeable Se, carbonate-bound Se, iron and manganese oxide-bound Se, humic acids-bound Se, organic matter-bound Se, and the residual Se fraction. The results showed that soluble Se, exchangeable Se, carbonate-bound Se, iron and manganese oxide-bound Se fractions accounted for less than 2% of the total Se, respectively. Organic matter-bound Se was the dominant fractions. The average concentrations (mg kg−1) of Se in the paddy tissues were 0.069 in seed, 0.263 in root, 0.09 in stalk, and 0.17 in leaf. The organic matter-bound Se had a significant indirect effect on Se accumulation in paddy tissues. In conclusion, organic matter-bound Se was an important fraction and source of plant Se in agricultural soil.

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Modes of Occurrence of Trace Elements (Na, K, Fe, Si) in Coal Used for COREX Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.391-392.81 ◽

2011 ◽

Vol 391-392 ◽

pp. 81-85

Author(s):

Li Hua Zhang ◽

Jia Xin Fan ◽

Sheng Li Wu

Keyword(s):

Trace Elements ◽

Sequential Extraction ◽

Iron Oxides ◽

Manganese Oxides ◽

Extraction Procedure ◽

Sequential Extraction Procedure ◽

Icp Oes ◽

Digestion Method ◽

Modes Of Occurrence ◽

Wet Digestion

In this paper, the modes of occurrence of the trace elements of Na, K, Fe and Si in SX-Coal and SD-Coal, which were used for COREX process, were analyzed. The coal was treated by wet digestion method and then the content of trace elements was analyzed. After that, the modes of occurrence of the elements were studied by sequential extraction procedure method and analyzed by ICP-OES. The results showed that the content of Na element is the highest and the content of K and Si elements is very low among the four elements in both kinds of coal. Na and K elements mainly exist in the mode of residue in SX-Coal and SD-Coal, and they are tends to enriched in the residue during the pyrolysis. Fe and Si elements mainly exist in the mode of carbonate, iron oxides and manganese oxides in SD-Coal. Fe and Si are tends to be decomposed from the compounds during the pyrolysis.

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Total and extractable forms of Cu, Zn, Ni, Cr, and Fe in vineyard soil (Valandovo valley, Macedonia) determined by a sequential extraction procedure

Macedonian Journal of Chemistry and Chemical Engineering ◽

10.20450/mjcce.2012.26 ◽

2012 ◽

Vol 31 (2) ◽

pp. 271 ◽

Cited By ~ 6

Author(s):

Elizabeta Karakaseva ◽

Blazo Boev ◽

Vesna Zajkova

Keyword(s):

Sequential Extraction ◽

Manganese Oxides ◽

Agricultural Soils ◽

Dominant Role ◽

Extraction Procedure ◽

Exchange Capacity ◽

Sequential Extraction Procedure ◽

Residual Fraction ◽

Chemical Conditions ◽

Almost All

The total and extractable forms of Cu, Zn, Pb, Ni, Cr, and Fe in vineyard soils from Valandovo valley were analyzed in order to understand the existence of metals in soils and their potential availability to the flora and fauna. The metals (Cu, Zn, Ni, Pb, Cr, and Fe) in soil was determined by by ICP-EAS and sequential extraction procedure [5]. Other chemical and physical properties such as pH, CEC (cation exchange capacity), organic matter, carbonate and particle size of soils collected from vineyards plots were also analyzed. The total concentrations of Cu, Zn, Pb, Ni, Cr, and Fe in almost all soil samples does not exceed the maximum permissible concentrations (MPC) of trace elements in agricultural soils proposed by Kabata-Pendias and Pendias (2001). The only exception was the soil sample R (3), where higher concentrations were measured especially for Fe, Ni and Cr, and to a lesser extent Cu and Zn. Sequence extraction shows that the distribution of metals increase in order: oxidisable (e.g., organic substance and sulphides) > fraction bound in the crystal lattice of silicate minerals (residual fraction) > reducible (e.g., iron/manganese oxides) > exchangeable, water and acid soluble (e.g., carbonates). The prevalence of metals in oxidisable fraction in the soil shows that this fraction has a dominant role in controlling the behavior and transport of these metals in soil. The low levels of metals in exchangeable and carbonate bound fraction (Ni (7,5%)>Pb (3,5%)> Cu (2,6%)> Zn (2,2%)> Cr (0,2%)) indicates a low rate of activity and mobility of these metals in soil solution caused by the current physico-chemical conditions in soil.

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Study of partitioning and dynamics of metals in contaminated soil using modified four-step BCR sequential extraction procedure

Chemical Papers ◽

10.2478/s11696-008-0102-3 ◽

2009 ◽

Vol 63 (2) ◽

Cited By ~ 11

Author(s):

Tiberiu Frentiu ◽

Michaela Ponta ◽

Erika Levei ◽

Emil Cordos

Keyword(s):

Organic Matter ◽

Sequential Extraction ◽

Soil Depth ◽

Extraction Procedure ◽

Organic Matter Content ◽

Sequential Extraction Procedure ◽

Solid Matrix ◽

Bcr Sequential Extraction ◽

Acid Media ◽

Baia Mare

AbstractThe modified four-step BCR sequential extraction procedure (exchangeable and weak acid available species, reducible, oxidisable and residual fractions) was used to examine the distribution of As, Cd, Cr, Cu, Pb, and Zn with soil depth in an area (Baia Mare — Bozanta, Romania) with both high natural level of elements considered as toxic and historical pollution resulting from nonferrous metallurgy. The BCR approach proved a high metal input of anthropogenic origin down to 40 cm, while at lower depths the naturally elevated metal content must be considered. Results of the partitioning study and XRD analysis of solid matrix showed the greatest potential for chemical remobilisation of Cd, Zn, and Cu in weak acidic medium as well as their affinity for the oxidisable fraction (organic matter/sulphide). The tendency of Cr, Pb, and As to be immobilised as residual or reducible species on Fe-Mn oxides was evident. Although the partitioning of As in chemically inactive forms such as scorodite (FeAsO4 · 2H2O) soluble under reducible conditions and beudantite (PbFe3(AsO4)(SO4)(OH)2)), a residual species soluble in acid media, chemical mobilisation from soil in groundwater was confirmed. Dynamic processes of metal retention in soil under different conditions, namely acidic, reducing or oxidisable, were predicted from the Pearsonșs correlation analysis of element species with soil characteristics and components such as Fe, Mn, organic matter content, pH, and total element content, respectively. At the moment of the study, soil and groundwater in the area were found to be polluted with As, Cd, Cu, Pb and Zn.

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