Tag Archives: humic acids

xxx M. Klavins, K. Upska, A. Viksna, M. Bertins, L. Ansone-Bertina and J. Krumins
A comparative study of the properties of industrially produced humic substances
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A comparative study of the properties of industrially produced humic substances

M. Klavins¹*, K. Upska¹², A. Viksna², M. Bertins², L. Ansone-Bertina¹ and J. Krumins¹

¹University of Latvia, Department of Environmental Science, 19 Raina Blvd, LV-1586 Riga, Latvia
²University of Latvia, Department of Analytical Chemistry, 19 Raina Blvd, LV-1586 Riga, Latvia
*Correspondence: maris.klavins@lu.lv

Abstract:

Humic substances (HSs) are produced industrially in large quantities from low rank coal, weathered coal, peat, also from soils, composts and other sources. Considering that the applications of industrially produced HSs also include food, pharmaceutical applications and environmental technologies, it is important to evaluate their composition and quality and to identify their sources. The aim of the present study is to compare the properties of industrially produced HS samples. HSs were characterised using spectroscopic and other methods. For the identification of origin of HSs, different methods can be used, such as elemental analysis and ratios of light stable isotopes. The results of the study indicate that many industrially produced HSs are of poor quality (low concentration of basic substance, admixture of undesirable substances, pollutants, no quality indications). In this situation, rigorous quality control should be implemented, providing detailed characteristics of the product. The composition of materials suggested for agricultural applications has not been analysed much. Most of the studied materials were designated as HAs, followed by fulvic acids (FAs) and HSs. However, an analysis of the humic matter types indicates that the majority of substances offered on the market are in fact mixtures of HAs and FAs; so, it would be more appropriate to designate them as HSs or their salts. This study identifies the main quality problems of industrially produced humic substances: 1) lack of strict quality indicators, 2) absence of indication of source materials/origins of HSs.

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1023–1032 M. Jemeljanova, R. Ozola and M. Klavins
Physical-chemical properties and possible applications of clay minerals and humic acid composite materials
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Physical-chemical properties and possible applications of clay minerals and humic acid composite materials

M. Jemeljanova*, R. Ozola and M. Klavins

Department of Environmental Science, University of Latvia, Raina Blvd. 19, LV-1586 Riga, Latvia
*Correspondence: marta.jemeljanova@gmail.com

Abstract:

Pollution caused by pharmaceuticals has become an increasingly serious issue, therefore innovative and cost – effective methods of pharmaceutical’s removal must be studied. Clay – humic acid composite materials can be considered as prospective and low cost sorbents for contaminants. The aim of this study is to develop clay mineral and humic acid composite materials and to characterise their possible applications. For this research, three types of clay minerals (montmorillonite, kaolinite and bentonite) were modified with three types of humic substances: technical humic acid from lignite, humic substances extracted from raised bog peat and technical K humate from lignite. The sorption was characterised according to the chosen clay mineral and humic acid type and concentration. The obtained material was characterised by Fourier Transform Infrared spectroscopy and Scanning Electron microscopy. The composite materials were tested for sorption of pharmaceuticals (chloropromazine hydrochloride). The obtained results characterise clay mineral and humic acid composite materials’ possible applications as sorbents for removal of pharmacologically active substances.

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1351-1359 B. Dalecka and L. Mezule
Study of potential PCR inhibitors in drinking water for Escherichia coli identification
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Study of potential PCR inhibitors in drinking water for Escherichia coli identification

B. Dalecka* and L. Mezule

Riga Technical University, Faculty of Civil Engineering, Water Research laboratory, Kipsalas 6A-263, LV-1048 Riga, Latvia
*Correspondence: brigita.dalecka_1@rtu.lv

Abstract:

In the last few decades, the polymerase chain reaction (PCR) has become one of the most powerful molecular biological tools. However, the PCR is an enzymatic reaction and therefore sensitive to inhibitors which may occur in drinking water samples. In this work, the possible inhibition effect of chlorine, humic acids, and iron for real-time PCR (qPCR) efficiency was studied and the environmental sample from drinking water treatment system before iron removal was selected and analysed. The results demonstrated that the highest concentrations of humic acids (5 mg L-1 and 1 mg L-1) and iron (4 mg L-1) inhibited the PCR reaction while no effect of chlorine was observed. The analysis of the environmental sample with spiked Escherichia coli cells demonstrated reduction efficiency of the average threshold cycle (Ct) values compared with control dilution series determining the possible inhibition for qPCR assay.

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728-736 H. Hospodarenko, I. Prokopchuk, S. Prokopchuk and А. Trus
Humus content in a podzolized chernozem after a long-term application of fertilizers in a field crop rotation
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Humus content in a podzolized chernozem after a long-term application of fertilizers in a field crop rotation

H. Hospodarenko¹, I. Prokopchuk¹*, S. Prokopchuk¹ and А. Trus²

¹Uman National University of Horticulture, Faculty of Agronomy, Department of Agricultural Chemistry and Soil Science, 1 Instytutska street, UA20305 Uman, Ukraine
²Uman National University of Horticulture, Faculty of Engineering and Technology, Department of Applied Engineering and Labor Protection, 1 Instytutska street, UA20305 Uman, Ukraine
*Correspondence: pivotbi@ukr.net

Abstract:

The article presents the results of the research into influence of a long-term (50 years) application of different fertilizer rates and fertilizer systems in the field crop rotation on the humus composition and optical parameters of humic acids of a heavy- loamy podzolized chernozem of the Right Bank Forest-Steppe of Ukraine.
It was found that application of fertilizers significantly affects the dominance of humic acids over fulvic acids in the composition of soil, which indicates humate type of soil. Chroma index of humic acids is within 3.56–3.75 depending on a fertilizer. Indicators of the optical properties of humic acids of a podzolized chernozem have a high degree of humification.

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397-402 A. Arlauskienė, S. Maikštėnienė and A. Šlepetienė
Effect of cover crops and straw on the humic substances in the clay loam Cambisol
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Effect of cover crops and straw on the humic substances in the clay loam Cambisol

A. Arlauskienė¹, S. Maikštėnienė¹ and A. Šlepetienė²

¹ Joniskelis Research Station of Lithuanian Institute of Agriculture, Joniskelis, LT-39301 Pasvalys distr., Lithuania; e-mail: joniskelio_lzi@post.omnitel.net
² Lithuanian Institute of Agriculture, Akademija, LT–58344 Kėdainiai distr., Lithuania

Abstract:

The experiments were done on a productive clay loam Gleyic Cambisol used for agricultural production and were designed to estimate the effects of various cover crops – red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) mixture with Italian ryegrass (Lolium multiflorum Lamk.) and white mustard (Sinapis alba L.) biomass and wheat (Triticum aestivum L.) straw incorporated into the soil on the composition of humus. In the first year, incorporation of only the cover crops’ biomass or together with straw increased the content of mobile humic acids (HA 1) by 10.7–28.0% compared with that before the trial was established.. Conditionally stable humic acids fractions (HA 2, HA 3) formed more intensively in the second year of the effects of the measures applied. Having incorporated cover crops’ biomass together with straw, the fraction of humic acids HA 3 tended to increase or was the same as that before the trial establishment. An increase in the content of humic acids, compared with the levels before the trial establishment determined positive changes in the one of the main indicators of humus quality – humification rate; they were the most distinct having incorporated red clover phytomass together with straw. The incorporation of mineral nitrogen fertilizer N 45 together with straw increased the soil organic matter mineralization rate and determined a reduction in humic acids content.

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