The mineralization of phenanthrene in pure cultures of a Pseudomonas fluorescens strain, isolated from soil, was measured in the presence of soil humic fractions and montmorillonite. Humic acid and clay, either separately or in combination, shortened the acclimation phase. A higher mineralization rate was measured in treatments with humic acid at 100 microg/ml. Humic acid at 10 microg/ml stimul...

Soil pollution by the presence of different contaminants (e.g. heavy metal ions or pesticides) is one of the biggest problems worldwide. The positive affinity of natural humic acids towards these contaminants might contribute to the soil and ground water protection; therefore it is necessary to study the reactivity and barrier properties of humic acids. An original reactivity-mapping tool based...

The molecular organization of humic acids in different aqueous solutions was studied over a wide concentration range (0.01-10 g·dm-3). Solutions of humic acids were prepared in three different media: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. Potentiometry, conductometry, densitometry, and high resolution ultrasound spectrometry were used in order to investig...

Humic substances and other dissolved organic matter (DOM) in Lake Biwa and the surrounding rivers were investigated to elucidate their origins and behavior. An annual increase in chemical oxygen demand (COD) has been observed in the northern basin of Lake Biwa since 1985. The concentrations of dissolved organic carbon (DOC) in the northern and southern basins of Lake Biwa were 1.7-2.4 mgC/l and...

The process of the radiolytic degradation is a new method of mineralization by advanced oxidation of the water that can be applied for the removal of humic compounds in all water systems. However, the deep mineralization of dissolved humic acid requires very high absorbed doses (tens of kilograys) because of the aromatic nature of the main units of humic acid and the well-known chemical and bio...

ARTICLE INFO ABSTRACTIn the past few decades, accumulation of heavy metals, such as lead (Pb), in soils has increased as a result of human activities.The environmental hazard associated with soil enrichment in heavy metals is related to their mobility and plant availability. Application of various materials such as humic may influence the amount of Pb taken up by plant. Four levels of each of l...

The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are discussed in detail. Experiments using cucumber (Cucumis sativus) plants show that the shoot growth enhancement caused by a structurally well-characterized humic acid with sedimentary origin is functionally associated with significant increases in abscisic acid (ABA) root concentration and roo...

Surface water and groundwater sources for human supply require treatment to remove substances that can cause human diseases and rejection. Aquatic humic substances, such as iron and manganese, interfere with the aesthetic and sanitary quality of the water because they cause color, odor and taste unpleasant. In addition, humic substances can form trihalomethanes which are serious harmful substan...

Background: Natural organic matters (NOMs) have the main role in formation of trihalomethanes. These compounds are in natural water sources due to biological activities. In the presented study, adsorption and separation of humic acid as an index of natural organic matters using multi-walled carbon nanotubes is evaluated. Methods: The experiments were carried out in bath adsorption reactors wit...

Field experiments were carried out during 2011-2014 at the Research and Experimental 13 Center to Combating Desertification located in the Elsen Tasarkhai station of central Mongolia. The 14 study was aimed to identify the effects of oxidized brown coal humic acid fertilizer on the relative 15 growth rate of several trees for forest rehabilitation. The trees used were Populus sibirica, Salix 16...