scholarly journals Changes in Organic Matter Composition Caused by EDTA Washing of two Soils Contaminated with Toxic Metals

2021 ◽  
Author(s):  
Erika Jez ◽  
Carlo Bravo ◽  
Domen Lestan ◽  
Simon Gluhar ◽  
Ladislau Martin-Neto ◽  
...  
Keyword(s):  
Organic Matter ◽  
Toxic Metals ◽  
Soil Washing ◽  
Free Fraction ◽  
Fulvic Acids ◽  
Significant Loss ◽  
Potentially Toxic Metals ◽  
Simultaneous Decrease ◽  
Humic Fractions

Abstract Two soils contaminated with potentially toxic metals (PTMs) contrasting in pH and mineralogy were remediated with CaEDTA, and changes in soil organic matter (SOM) composition were investigated. Previous studies showed no significant loss of SOM from CaEDTA-treated soils, but the results of our study reflected significant decreases (from 46 to 49%) in the free fraction of humic acids (HAs). Remediation affected the composition of the free HA fraction via disturbance of intermolecular bonds - an increase in phenolic and aromatic groups with a simultaneous decrease in carbohydrates - which was confirmed by FTIR spectroscopy in both soils. Because non-radical molecules such as carbohydrates were selectively removed, the concentration of free radicals in the free HA fraction increased in acidic soil. The bound fraction of HAs and fulvic acids (FAs) in SOM, which are important due to their stability and the permanent effects they have on the soil’s physical properties, remained unchanged in both remediated soils. The effect of soil recultivation was observed only in the EEM fluorescence spectra of HAs. In terms of SOM, CaEDTA soil washing can be considered moderately conservative, however, the restoration of free humic fractions is likely to be a long-term process.

scholarly journals Changes in organic matter composition caused by EDTA washing of two soils contaminated with toxic metals

2021 ◽  
Author(s):  
Erika Jez ◽  
Carlo Bravo ◽  
Domen Lestan ◽  
Simon Gluhar ◽  
Ladislau Martin-Neto ◽  
...  
Keyword(s):  
Organic Matter ◽  
Toxic Metals ◽  
Soil Washing ◽  
Free Fraction ◽  
Fulvic Acids ◽  
Significant Loss ◽  
Potentially Toxic Metals ◽  
Simultaneous Decrease ◽  
Humic Fractions

AbstractTwo soils contaminated with potentially toxic metals (PTMs) contrasting in pH and mineralogy were remediated with CaEDTA, and changes in soil organic matter (SOM) composition were investigated. Previous studies showed no significant loss of SOM from CaEDTA-treated soils, but the results of our study reflected significant decreases (from 46 to 49%) in the free fraction of humic acids (HAs). Remediation affected the composition of the free HA fraction via disturbance of intermolecular bonds — an increase in phenolic and aromatic groups with a simultaneous decrease in carbohydrates — which was confirmed by FTIR spectroscopy in both soils. Because non-radical molecules such as carbohydrates were selectively removed, the concentration of free radicals in the free HA fraction increased in acidic soil. The bound fraction of HAs and fulvic acids (FAs) in SOM, which are important due to their stability and the permanent effects they have on the soil’s physical properties, remained unchanged in both remediated soils. The effect of soil recultivation was observed only in the excitation emission matrix (EEM) fluorescence spectra of HAs. In terms of SOM, CaEDTA soil washing can be considered moderately conservative; however, the restoration of free humic fractions is likely to be a long-term process.

scholarly journals Impact of different fallow durations on soil aggregate structure and humus status parameters

2019 ◽  
Vol 15 (No. 1) ◽  
pp. 1-8 ◽  
Author(s):  
Maksim Burdukovskii ◽  
Irina Kiseleva ◽  
Polina Perepelkina ◽  
Yuliya Kosheleva
Keyword(s):  
Organic Matter ◽  
Soil Structure ◽  
Russian Far East ◽  
Arable Land ◽  
Fulvic Acids ◽  
Soil Aggregate ◽  
Aggregate Structure ◽  
Fallow Period ◽  
Humus Status

Soil aggregate structure and soil organic matter are closely interrelated and commonly considered as key indicators of soil quality. The aim of this study was to evaluate the effects of different fallow durations on indices of soil structure and humus status indicators. Studies were conducted on abandoned agricultural fields (15, 20 and, 35 years after abandonment). As a reference site, we used a cultivated field in the area. The experimental soil fields are classified as Gleyic Cambisols. Soil macroaggregates were separated with the sieve (dry sieve) to seven aggregate size fractions, i.e.&gt; 10, 10–5, 5–2, 2–1, 1–0.5, 0.5–0.25 and &lt; 0.25 mm. The humus status parameters of soils included the following indicators: soil organic carbon (C<sub>org</sub>), humus reserves (Q<sub>H</sub>), the degree of humification of organic matter (SOM<sub>dh</sub>), fractions of humic acids (HA) (free and bound with monovalent cations and Al<sub>2</sub>O<sub>3</sub>, Fe<sub>2</sub>O<sub>3</sub>, bound with Са<sup>2+</sup> which forms humates, bound with clay minerals), fulvic acids (FA) (free aggressive) and ratio of HA to FA (C<sub>HA</sub><sub> </sub>: C<sub>FA</sub>). After a fallow period of more than 20 years on the surface formation of a sod layer. A long-term fallow period had an impact on the mean weight diameter of the aggregates (MWD) and agronomically valuable aggregates (AVA). Fallow soils have a significantly better structure than soils under a cultivated field. Long-term cultivation leads to the deterioration of soil structure and the formation of large aggregates (&gt;10 mm). The C<sub>org</sub> content remains at the level of the background content when the soils are left fallow for less than 15 years and increases over time. The C<sub>org</sub> in the upper 0–20 cm soil layer has been shown to increase from 3.55 to 8.74% on arable land that has been fallow for 35 years and has been largely associated with significant accumulation of organic matter within the plant root mass. Mature sites are characterized by an increase of fulvic acids in the humus composition in comparison with their arable analogues. The abandonment of soil agricultural use and the cessation of mechanical tillage results in the restoration of the natural structure of soils and the improvement of their agrophysical properties. Such studies have not been previously conducted in the Primorsky region of the Russian Far East.

Using Modified Tessier Scheme to Metal Speciation in a Former Sewage Farm and interpretation of the sequential extraction by FTIR

2021 ◽  
Author(s):  
Shaghayegh Ramezany ◽  
Magdalena Sut-Lohmann ◽  
Friederike Klos ◽  
Alexander Bonhage ◽  
Thomas Raab
Keyword(s):  
Organic Matter ◽  
Sequential Extraction ◽  
Toxic Metals ◽  
Agricultural Land ◽  
Metal Speciation ◽  
Metal Extraction ◽  
Residual Fraction ◽  
Potentially Toxic Metals ◽  
Sewage Farm ◽  
Mn Oxides

&lt;p&gt;We present a study conducted on a former sewage farm near Berlin, where long term sewage disposal onto agricultural land resulted in a high accumulation of potentially toxic metals. Based on a previous study, 30 samples collected within an area of a former sedimentation basin were selected (at the depth of 15-20 cm and one borehole up to 100 cm deep). The modified Tessier sequential extraction was applied in order to determine the partitioning of particulate potentially toxic metals (Cr, Cu, Ni, Pb, and Zn) into following fractions: 1) Exchangeable, 2) Bound to carbonate, 3) Bound to Fe/Mn oxides, 4) Bound to organic matter, and 5) Residual fraction. As a complementary analysis, diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) technique was used for the interpretation purposes.&lt;/p&gt;&lt;p&gt;The obtained results demonstrated different metal speciation in the studied soil; Pb was mostly discovered in the residual fraction (77%) followed by Cr (53%), Cu (8%), and Zn (5%), while Ni was not extracted in this fraction. The organic matter-bound is the dominant species of Cu (77%). However, Zn and Ni exhibit the highest affinity for Fe/Mn oxides fraction (55% and 39%, respectively). The average mobility factor followed the order Ni &gt; Zn &gt; Cu whereas Cr and Pb were not found as exchangeable nor in carbonate forms. Study also revealed that DRIFTS is applicable to interpret the sequential metal extraction, especially for the carbonates-bound, organic matter-bound, and residual fractions. The spectral changes in organic and inorganic regions can indicate the soil components&amp;#8217; dissociation is proportional to the extraction.&lt;/p&gt;

Quality and dynamics of soil organic matter in a typical Chernozem of Ukraine under different long-term tillage systems

2012 ◽  
Vol 92 (3) ◽  
pp. 429-438 ◽  
Author(s):  
Y. Kravchenko ◽  
N. Rogovska ◽  
L. Petrenko ◽  
X. Zhang ◽  
C. Song ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Acids ◽  
Fulvic Acids ◽  
Soil Tillage ◽  
Typical Chernozem ◽  
Tillage Systems ◽  
Organic C ◽  
Molecular Masses

Kravchenko, Y., Rogovska, N., Petrenko, L., Zhang, X., Song, C. and Chen, Y. 2012. Quality and dynamics of soil organic matter in a typical Chernozem of Ukraine under different long-term tillage systems. Can. J. Soil Sci. 92: 429–438. Tillage has been reported to induce changes in soil organic matter (SOM) concentrations and quality. Conversion of plow-tillage to minimum till and no-till (NT) farming enhances the SOM pool. Enrichment of the SOM pool is essential for maintaining fertility of Chernozems, advancing food security, and improving the environment. The main objective of this study was to examine the effect of different tillage systems on the SOM concentration, its quality and dynamics including CO2 assimilation by heterotrophic bacteria and humus characteristics – the carbon (C) concentration in humic substances and the labile soil organic C fraction (SOCL) extracted with 0.1 N NaOH – as well as the molecular masses, spectroscopic parameters and physiological effects of humic acids on germinating pea (Pisum sativum L.) seeds. Our study was conducted on a long-term experimental site on a Haplick Chernozem in the Poltava region of Ukraine over a 10-yr period from 1996 to 2006. Results indicate that conversion from conventional to reduced soil tillage systems increased SOM concentrations in 0- to 10-cm soil layer and led to the accumulation of C in fulvic acids and humins. No significant differences in SOM storage in the 0- to 100-cm layer were observed among tillage systems. However, reduced tillage systems had a higher proportion of SOCL, a lower ratio of C in humic acids/C in fulvic acids and more humic acids with molecular masses from 110 to 2000 kDa. Our study demonstrated that the quality and dynamics of SOM are closely related to soil tillage practices.

Comparing the Genetic Detox Ability and Heavy Metal Burden in a Cohort of Samples of Egyptian Children and those with Autistic Spectrum Disorder

2019 ◽  
Author(s):  
Blaurock-Busch E
Keyword(s):  
Heavy Metal ◽  
Autism Spectrum ◽  
Control Group ◽  
Potentially Toxic Metals ◽  
Gstt1 Null Genotype ◽  
Egyptian Children ◽  
Glutathione S Transferases ◽  
Metal Burden ◽  
Detoxification Pathway

The heavy metal burden of patients with Autism spectrum disorders (ASD) has been widely discussed [1-5]. Present knowledge suggests that ASD patients, compared to ‘normal’s’ show a greater metal burden, which may be a cause of the ASD pathogenesis, possibly due to a limited detoxification potential. We thus aimed to evaluate if the metal burden of ASD children is due to comprised detoxification ability, and if missing of enzymes such as the glutathione-S-transferases provide an explanation, or if additional factors play a role. Genetically, we noticed a slight difference in the detoxification ability of the ASD group compared to the Control group. In the ASD group, carrier of the genotype GSTT1 null genotype (i.e. the homozygous loss) are 1.7 times more common as in the Control group and the GSTT1 allele is more frequent in the ASD patient collective. These findings are not statistically significant but indicate a trend. In addition, our data indicates that levels of potentially toxic metals in blood and hair of both groups demonstrate a similar immediate and long-term exposure. However, 36% of the ASD group showed signs of zinc deficiency compared to 11% of the Control group and this points towards inefficiency of the Phase I detoxification pathway. More research is needed to explore the role of other elements in the detoxification pathway.

Reports From the Field: “Vini Ansanm” Come Together for Inclusive Community Music Development in Port-au-Prince, Haiti

2020 ◽  
pp. 273-289
Author(s):  
Donald DeVito ◽  
Gertrude Bien-Aime ◽  
Hannah Ehrli ◽  
Jamie Schumacher
Keyword(s):  
Social Media ◽  
Inclusive Education ◽  
Children With Disabilities ◽  
Small Population ◽  
Significant Loss ◽  
Community Music ◽  
Music Learning ◽  
Loss Of Life

Haiti has experienced a series of catastrophic natural disasters in recent decades, resulting in significant loss of life and long-term damage to infrastructure. One critical outcome of these disasters is that there are approximately 400,000 orphans in the small population of just over 10 million. Throughout Haiti, children with disabilities are often considered cursed, and thus are rejected by the community in which they live. Haitian children with disabilities need creative and educational activities that will help them grow, develop, enjoy their lives, and become accepted members of the community. This chapter on the Haitian Center for Inclusive Education presents a case study of social media engagement and music learning, with an emphasis on social justice that has contributed to sustainable efforts.

scholarly journals Impacts of long-term plant residue management on soil organic matter quality, Pseudomonas community structure and disease suppressiveness

2019 ◽  
Vol 135 ◽  
pp. 396-406 ◽  
Author(s):  
Bryony E.A. Dignam ◽  
Maureen O'Callaghan ◽  
Leo M. Condron ◽  
Jos M. Raaijmakers ◽  
George A. Kowalchuk ◽  
...  
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Soil Organic Matter ◽  
Residue Management ◽  
Plant Residue ◽  
Organic Matter Quality ◽  
Soil Organic Matter Quality

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

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