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The bioconversion of phenolic monomers of lignin (veratrol, vanillin, and vanillyl alcohol), hydrolyzed lignin, and sodium lignosulfonate (a product of the chemical modification of native lignin) by the basidiomycete Lentinus tigrinus was studied. It was found that the growth of the fungi on lignin monomer compounds is suppressed. A noticeable growth of the fungal biomass was observed only on the technical substrate sodium lignosulfonate. A comprehensive physicochemical study of the products of microbial transformation of sodium lignosulfonate was performed. It was established that the main direction of lignin bioconversion is oxidative condensation to form humic substances. In this case, depolymerization of the phenolic skeleton of lignin to monomeric phenol derivatives did not occur. The aromatic carbon atoms of the phenolic skeleton, unlike the carbon atoms of polysaccharides, were not involved in the fungal biomass growth. The observed growth of the fungus on the technical substrate sodium lignosulfonate can be explained by the presence of admixtures of oligomeric polysaccharides hemicellulose and cellulose, which can be used by the fungus as a carbon source.

Natural products (e.g., polyphenols) have been used as biologically active compounds for centuries. Still, the mechanisms of biological activity of these multicomponent systems are poorly understood due to a lack of appropriate experimental techniques. The method of tritium thermal bombardment allows for non-selective labeling and tracking of all components of complex natural systems. In this study, we applied it to label two well-characterized polyphenolic compounds, peat fulvic acid (FA-Vi18) and oxidized lignin derivative (BP-Cx-1), of predominantly hydrophilic and hydrophobic character, respectively. The identity of the labeled samples was confirmed using size exclusion chromatography. Using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS), key differences in the molecular composition of BP-Cx-1 and FA-Vi18 were revealed. The labeled samples ([3H]-FA-Vi18 (10 mg/kg) and [3H]-BP-Cx-1 (100 mg/kg)) were administered to female BALB/c mice intravenously (i.v.) and orally. The label distribution was assessed in blood, liver, kidneys, brain, spleen, thymus, ovaries, and heart using liquid scintillation counting. Tritium label was found in all organs studied at different concentrations. For the fulvic acid sample, the largest accumulation was observed in the kidney (Cmax 28.5 mg/kg and 5.6 mg/kg, respectively) for both routes. The organs of preferential accumulation of the lignin derivative were the liver (Cmax accounted for 396.7 and 16.13 mg/kg for i.v. and p.o. routes, respectively) and kidney (Cmax accounted for 343.3 and 17.73 mg/kg for i.v. and p.o. routes, respectively). Our results demonstrate that using the tritium labeling technique enabled successful pharmacokinetic studies on polyphenolic drugs with very different molecular compositions. It proved to be efficient for tissue distribution studies. It was also shown that the dosage of the polyphenolic drug might be lower than 10 mg/kg due to the sensitivity of the 3H detection technique.

Redox moieties, which are present in the molecular backbone of humic substances (HS), govern their antioxidant properties. We hypothesized that a directed modification of the humic backbone via incorporation of redox moieties with known redox properties might provide an efficient tool for tuning up antioxidant properties of HS. In this work, hydroquinonoid and hydronaphthoquinonoid centres were used, which possess very different redox characteristics. They were incorporated into the structure of coal (leonardite) humic acids CHA) and peat fulvic acids (PFA). For this goal, an oxidative copolymerization of phenols was used. The latter was induced via oxidation of hydroquinones and hydroxynapjtaquinones with a use of Fenton’s reagent. The structure of the obtained products was characterized using NMR and FTIR spectroscopy. H/D labelling coupled to FT ICR mass spectrometry analysis was applied for identification of the reaction products as a tool for surmising on reaction mechanism. It was shown that covalent -C-C- bond were formed between the incorporated redox centers and aromatic core of HS. The parent humic acids and their naphthoquinonoid derivatives have demonstrated high accepting capacity. At the same time, fulvic acids and their hydroquinonoid derivatives have possessed both high donor and high antioxidant capacities. The kinetic studies have demonstrated that both humic acids and their derivatives showed much slower kinetics of antioxidant reactions as compared to fulvic acids. The obtained results show, firstly, substantial difference in redox and antioxidant properties of the humic and fulvic acids, and, secondly, they can serve as an experimental evidence that directed chemical modification of humic substances can be used to tune and control antioxidant properties of natural HS.

The conference "Results and prospects of development of new polyphenolic drugs for cancer patients" took place at the N.N. Petrov National Medical Research Center of Oncology (PNMRCO) on May 31, 2017, and gathered researchers involved in development and evaluation of medicinal products based on the novel lignin-derived soluble polyphenolic polymer BP-Cx-1. BP-Cx-1 is the platform for a portfolio of innovative pharmacological products such as BP-C1, BP-C2 and BP-C3.

Natural self-cleaning processes are a special focus area in searching for cost-effective and environmentally sound technologies for minimizing the oil spot effect on water areas. From this perspective, a viable alternative to existing soluble xenobiotic dispersants may be provided by highly dispersed solid particles. They can be used in technologies based on formation of stable oil-in-water emulsions that can sink down below the water surface to be further degraded by microorganisms. In this context, the formation conditions for oil-mineral aggregates, ways of stabilization of oil-in-water emulsions by highly dispersed solid particles, and factors affecting their formation efficiency were considered, as well as the prospects for their application in oil spill remediation technologies for open and coastal water areas.

Adsorption of a broad range of humic substances (HS) of different origins and fractional compositions on a macroporous weakly basic anion-exchange resin is studied. It is found that the nature of the HS has a substantial effect on both the efficiency of sorption and the mechanism of interaction with the adsorbent. The dependence of the determined thermodynamic parameters of sorption on the HS origin, composition, and structure is shown for a broad range of HS. It is concluded that the results can be used to predict the sorption properties of weakly basic anion-exchange resins with respect to HS of known origin and structural group composition.

The structural-group composition and seasonal variations of organic matter dissolved in potable water and water sources of Ufa is studied. The efficiency of removal and destruction rate of dissolved organic matter at different technological stages of water treatment is evaluated for a surface water intake.

The growth of gold nanoparticles (AuNPs) assisted by humate – a natural hyperbranched polyelectrolyte – was studied using in situ and ex situ techniques. The conditions for formation of almost monodisperse gold nanospheres of 13 ± 3 nm diameter with pronounced plasmonic properties were defined. A striking similarity was found between humate- and citrate-mediated growth of AuNPs: the formation of gold nanospheres involved rapid nucleation of gold seeds, slow growth within the intermediate agglomerates (visible as nanoworms after drying on a TEM grid), and rapid peptization into the final gold nanospheres. Both humate and citrate syntheses produced ultrastable gold sols with pronounced plasmonic properties. The substantial difference was slower kinetics of humate synthesis, 240 min versus 15 min for citrate, and the water redispersible properties of the humate-capped gold nanospheres after freeze drying, which was not seen with the citrate AuNPs. Theoretical calculations revealed a leading role of steric factors in the formation of intermediate aggregates of capped AuNPs at the stage of their slow growth in the case of both citrate and humate. We suggested that it was the polyelectrolyte nature of humate which enabled the water-redispersibility of humate- versus citrate-capped gold nanoparticles.

This article focuses on linking structures of fractionated humic polyanions (PAs), which were molecularly defined using ultrahigh resolution Fourier transform mass spectrometry (FTMS), to their antiviral activities with respect to laboratory HIV-1 strains. Anti-HIV-1 activity was proven using a full HIV-1 replication system validated for antiviral testing. We demonstrated that all humic PAs tested in our study were capable of inhibiting HIV fusion. The most hydrophobic fractions of humic and hymatomelanic PAs also strongly inhibited HIV-1 reverse transcriptase. The structure–activity analysis revealed the direct relationship of antiviral activities with contribution of CHO molecules in humic PA composition and lipophilicity index, and the inverse relationship with their carboxylic and total acidity. This was explained by the supramolecular character of humic PAs, the properties of which are ruled rather by the contribution of most potent scaffolds than by the total charge density. It is concluded that all humic PAs tested in this study can be considered as promising precursors for developing cost-effective combinatorial microbicides with polymodal anti-HIV activity and low cytotoxicity capable of preventing HIV-1 transmission.

Humic substances (HS) in the aqueous solutions can be considered as colloidal particles formed by amphiphilic units. HS form micelles-like structures at concentrations close to 5 g/L. However colloidal behavior of HS at concentrations below 100 mg/L is unknown. Using radiotracer assay we have shown that in this concentration range HS form rare adsorption layers at the liquid/liquid interface and penetrate into the organic phase with the distribution ratio close to 10−3. We found that pH and HS molecular weight strongly influence on the distribution ratio but do not significantly change the adsorption. Furthermore, colloidal properties of HS are strongly depending on its origin: the highest surface activity was shown for HS separated from peat and the least was observed for HS separated from soils. We anticipate our assay to be a helpful tool for detailed analysis and modeling HS and humic-like materials colloidal behavior in the environment.

The state of the art of the reported data on interactions between microorganisms and HSs is presented herein. The properties of HSs are discussed in terms of microbial utilization, degradation, and transformation. The data on biologically active individual compounds found in HSs are summarized. Bacteria of the phylum Proteobacteria and fungi of the phyla Basidiomycota and Ascomycota were found to be the main HS degraders, while Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes were found to be the predominant phyla in humic-reducing microorganisms (HRMs). Some promising aspects of interactions between microorganisms and HSs are discussed as a feasible basis for nature-like biotechnologies, including the production of enzymes capable of catalyzing the oxidative binding of organic pollutants to HSs, while electron shuttling through the utilization of HSs by HRMs as electron shuttles may be used for the enhancement of organic pollutant biodegradation or lowering bioavailability of some metals. Utilization of HSs by HRMs as terminal electron acceptors may suppress electron transfer to CO2, reducing the formation of CH4 in temporarily anoxic systems. The data reported so far are mostly related to the use of HSs as redox compounds. HSs are capable of altering the composition of the microbial community, and there are environmental conditions that determine the efficiency of HSs. To facilitate the development of HS-based technologies, complex studies addressing these factors are in demand.

The paper is devoted to the development and performance testing of a soil conditioner based on leonardite humic substances (LHS) modified with 3-aminopropyltriethoxysilane (APTES). The modified HS were obtained by adding APTES to LHS solution at different mass ratios of LHS and APTES, followed by the investigation of siloxane structures using 31Si NMR spectroscopy. The Urbic Technosol was used as a model soil. The size and amount of water-stable soil aggregates were estimated using wet sieving and laser diffraction, respectively. Toxicity was evaluated by monitoring microbial substrate-induced respiration (SIR) and seedling bioassay. Laboratory column experiments demonstrated an increase in water-stability of the 3&ndash, 5 mm soil aggregates after LHS-APTES application. Field tests showed an increase in the average weighted diameter of micro aggregates (from 59 to 73 &mu, m) and water-stable macroaggregates (from 1.6 to 2.9 mm) due to the LHS-APTES amendment. A substantial increase in SIR from 5 to 9 mg CO2 (kg h)&minus, 1 was detected. Better survival of seedlings was observed. The obtained beneficial results indicate that APTES-modified HS can be successfully used as a soil conditioner. The formation of extended siloxane networks was suggested as the main mechanism of the observed improvement in the structure of the amended soils.

The objective of the study was to obtain quantitative assessments of the hydrophobic impact of irreversible sorption of humic substances (HSs) onto clay mineral surfaces using a sessile drop contact angle method. Two clays (kaolin and montmorillonite) were modified with four humic materials: (1) sod podzolic soil, (2) chernozem, (3) peat, and (4) coal (leonardite). The humic materials were characterized using elemental analysis, size exclusion chromatography, and 13C NMR spectroscopy. Both clay samples were saturated with Ca2+ prior to modification with HS using a sorption isotherm technique. Contact angles (CAs) of the obtained HS-clay complexes were determined using a static sessile drop method after drying the obtained HS-clay complexes in the form of a thin film. HS modification rendered both clays under study—kaolin and montmorillonite—more hydrophobic. In case of Ca-kaolin, the CA values increased from 27° (Ca-kaolin) up to 31°–32° (all HS-kaolin complexes) with no significant difference among the HS types used for modification. In the case of Ca-montmorillonite, the CA values increased from 41° (Ca-montmorillonite) up to 51°–83° with the following ascending trend for the humic types investigated: chernozem HS < coal HS < peat HS < sod-podzolic HS. This trend is in reverse to the degree of aromaticity of the HS, expressed as the content of aromatic carbon, and it is directly proportional to the molecular weight of each HS. Application of a sessile drop method showed increased surface hydrophobicity of HS-modified clays. Much more substantial hydrophobization was observed for montmorillonite as compared to kaolin, which was explained by the differences in the sorption mechanism.

The effect of humic acids (HAs) and their iron complexes (Fe–HAs) on the input of the main mineral elements into wheat seedlings, as well as on the efficiency of photosynthesis and the lipid profile of plants, under iron deficiency has been studied. The input of iron from Fe–HA complexes and its predominant accumulation in roots are demonstrated. It is found that HAs increase the efficiency of photosynthesis due to enhanced electron transport in photosystem II. It is shown that the application of HAs and Fe–HAs is accompanied by an enhanced input of Zn into plants, which could increase the antioxidant status of plants under iron deficiency conditions. In addition, a pronounced increase in the content of lipids in plants is revealed, which is indicative of the effect of HAs on plant metabolism. The obtained results suggest that the positive effect of Fe–HAs and HAs on plants under iron deficiency conditions is due to a combination of factors, among which the effect of HAs on the antioxidant status of plants and the plant lipid metabolism predominates.

The purpose of the present study is to evaluate slow-release nitrogen capabilities of soil amendments obtained by modification of humic materials from peat and lignite with alkoxyorganosilanes carrying different amine substituents. The humates from lignite and peat were modified using (3-aminopropyltriethoxy)-silane (APTES) and (1-aminohexamethylenene, 6-aminomethylene)-triethoxysilane (AHATES). The obtained derivatives were characterized using elemental analysis and Fourier transform infrared spectroscopy. Nitrogen release in the form of ammonia or nitrate was evaluated using dissolution tests under sterile aqueous conditions as well as long-term soil experiments. Ammonium and nitrate were determined using ion-selective electrodes. Activity index (AI) was calculated from the dissolution tests. For soil trials, arable Retisol was sampled from 0- to 5-cm layer in Yaroslavl region (Russia). The soil experiments were conducted over 78 days using (NH4)2SO4 as an activator of nitrification and 3-amino-1,2,4-triazole as an inhibitor of autotrophic nitrifying bacteria. Modification of lignite and peat humates leads to an increase in nitrogen content up to 2 and 4.3 %, respectively, in case of APTES, and up to 3 and 6 %, respectively, in case of AHATES. All humic derivatives gradually released N upon dissolution in water over 6 days up to 51 % of the total N. The AI values ranged from 4 to 13 %. Amendment of soil with the modified humic materials induced an increase in nitrate content resulting from nitrification of released ammonia by soil microflora. This was confirmed by aminotriasole experiments. The nitrogen release occurred slowly: over the first week of incubation, it did not exceed 36–69 % of the total N content. The higher release rate of ammonium nitrogen was observed for CHS-AHATES versus CHS-APTES derivative, whereas no difference was seen between the two peat derivatives, which showed release rate on the level of CHS-AHATES derivative. Positive effect of all modified humic materials lasted over 78 days. Modification of lignite and peat humates with two aminoorganosilanes carrying one and two nitrogen atoms in the amine substituent brought about twofold to threefold enrichment of the parent humic materials with nitrogen, which was capable of slow release upon incubation in soils. It was released in the form of ammonia and transformed to nitrates by autotrophic nitrifying soil microflora. There was no clear relationship established between structure of amine substituent of organosilane and slow-release properties of the corresponding humic derivatives. The conclusion was met that principal application of aminoorganosilane derivatives of humic substances (HS) is soil structuring, whereas nitrogen-fertilizing capabilities might be considered as beneficial added-value feature of these humic products.

This paper presents the fundamental theory and laboratory test results on a new device that is deployed in boreholes in fractured rock aquifers to characterize vertical distributions of water and contaminant fluxes, aquifer hydraulic properties, and fracture network properties (e.g., active fracture density and orientation). The device, a fractured rock passive flux meter (FRPFM), consists of an inflatable core assembled with upper and lower packers that isolate the zone of interest from vertical gradients within the borehole. The outer layer of the core consists of an elastic fabric mesh equilibrated with a visible dye which is used to provide visual indications of active fractures and measures of fracture location, orientation, groundwater flux, and the direction of that flux. Beneath the outer layer is a permeable sorbent that is preloaded with known amounts of water soluble tracers which are eluted at rates proportional to groundwater flow. This sorbent also captures target contaminants present in intercepted groundwater. The mass of contaminant sorbed is used to quantify cumulative contaminant flux; whereas, the mass fractions of resident tracers lost are used to provide measures of water flux. In this paper, the FRPFM is bench tested over a range of fracture velocities (2–20 m/day) using a single fracture flow apparatus (fracture aperture = 0.5 mm). Test results show a discoloration in visible dye corresponding to the location of the active fracture. The geometry of the discoloration can be used to discern fracture orientation as well as direction and magnitude of flow in the fracture. Average contaminant fluxes were measured within 16% and water fluxes within 25% of known imposed fluxes.

Using the size-exclusion chromatography method, the molecular-mass distribution of dissolved organic matter of drinking water and water sources of Ufa is studied. The influence of seasonal changes and various water treatment stages on the molecular-mass distribution of dissolved organic matter is shown.

Birch tar was widely used since the Stone Age as adhesive, disinfectant, mosquito repellent etc. Despite of this, the chemical composition of the birch tar remains largely unknown. Here we implement the electrospray ionization ultrahigh resolution Fourier transform mass spectrometry for the determination of the molecular formulas of the birch tar constituents. It was found that in the positive ESI mode the compounds containing 2 nitrogen atoms dominates in the spectrum. Compounds containing 1 nitrogen atom were detected too but they are less abundant. In the negative ESI mode the compounds containing from 2 to 4 oxygen atoms were detected. Also, we used recently developed in-ESI source Hydrogen/Deuterium exchange approach for the structural characterization of the individual molecules. We observed the 1 H/D exchange for major O 3 compounds and did not observe H/D exchange for almost all O 2 compounds. Corresponding neutral molecules have 2 and 1 labile hydrogens and as a consequence –OH groups respectively.

Humic substances (HS) have been extracted from fresh waters on macroporous adsorbents of different types, Amberlite XAD-8 resin and Bond Elute PPL solid-phase cartridge. Comparative analysis of the extracted samples by ultra-high resolution mass spectrometry demonstrated selectivity of the selected adsorbents to the components of the molecular assembly of HS: the XAD-8 resin has affinity to the higher oxidized aromatic compounds and PPL has affinity to substances of stronger aliphatic character and nitrogen-containing compounds. Because of this fact, a comparison of the molecular composition of HS isolated from various sources must be performed taking into account selective adsorption; therefore, it is necessary to compare the products extracted by the same adsorbent for correct interpretation.

In this study we successfully enhanced surface activity of natural humic substances (HS) with respect to mineral surfaces by functionalization with organosilanes. Of particular importance was that modification was conducted in water. Humates from coal and peat and 3-aminopropyl-triethoxysilane (APTES) were used as starting materials. Atomic force microscopy showed silanized HS produced self-assembled adsorption monolayers at the water–solid interface. These adlayers caused an increase in the surface hydrophobicity with contact angles equaling 56°. Application of silanized HS for treatment of different soil compartments including mineral soil separates and soil aggregates revealed an efficacy with respect to both re-assembly of soil aggregates and restoration of their water stability. Furthermore, field trials on the treatments of native sod-podzolic soil with silanized HS indicated improvements in soil structure as compared to non-treated soil or treatment with the non-functionalized humate. Results demonstrating the use of silanized HS as ecologically-safe, nature-inspired soil conditioners were promising.

The objective was to estimate suitability of humics-modified silica gels for adsorptive removal of the Direct Brown 1 trisazo dye from aqueous phase. The major advantage of the proposed adsorbents is that of an ecologically sound procedure of immobilizing silanized humic derivatives onto silica gel in aquatic solutions. The silanized humic derivatives, in turn, are obtained without a use of organic solvent by reacting natural humic materials from peat and coal with 3-aminopropyltriethoxyorganosilane in water. These silanized derivatives are surface active and are capable of self assembling into humic adlayers at the water solid interface. A use of this approach allows for immobilization of up to 220 mg of humic materials per 1 g of SiO2. The adsorption capacity of humics-modified silica gels with respect to the Direct Brown 1 trisazo dye varied from 3.5 up to 8.8 mg per 1 g of SiO2. The maximum sorption obtained for the silanized derivative with 50% modification degree was comparable to adsorption capacity of activated coal to this dye (7.5 mg g(-1)). The results of this adsorption study, warrant further studies of azo dye removal from aqueous environments.

Water-based humic substances-silsesquioxane (HS-SQ) soft materials are synthesized by hydrolysis of (3-aminopropyl-triethoxy)-silane in the HS solution. The aggregation dynamics of this system was studied using in situ small-angle X-ray scattering (SAXS) technique, which revealed three consecutive stages in the evolution of the HS-SQ system based on its fractal dimension (D): HS-SQ oligomeric polyelectrolyte complexes with D 3 (surface fractals). It was suggested that the reaction time needed for the HS-SQ system to transit from mass to surface fractal stage can be used to control its self-assembly onto a solid support. The corresponding studies have confirmed that the HS-SQ networks could be successfully immobilized onto sand columns only at the aggregation stage with fractal dimensions of 2.5 < Dm < 3. This enabled the targeted design of HS-SQ systems capable of guided self-assembly onto the solid support. The corresponding lab column studies have demonstrated successful passive installation of a humic permeable reactive barrier on sand which was capable of intercepting azo dyes from contaminated water. The prospects of using HS-SQ soft materials in nature-inspired remedial technologies and soil restoration are discussed.

Interactions of aliphatic and aromatic amines with soil and humic acids isolated from it are studied by means of spin labels and electron paramagnetic resonance (EPR) spectroscopy. Nitroxyl radicals containing amino groups are used as spin labels. It is found experimentally that aromatic amines are instantaneously converted to the bound state. It is shown that the microareas of their incorporation are characterized by a significant delay in the reduction of the nitroxyl fragment of spin-label molecules, indicating the formation of condensed structures typical of an oxidative binding mechanism. It is concluded that aliphatic amines do not bind to humic acids. It is noted that the studied process allows elucidating the formation of bound xenobiotic residues in soils.

Fourier transform ion cyclotron resonance mass spectrometry reveals substantial differences in the structural motifs of lignite and leonardite humates, which can be used for the standardization and molecular systematics of humic substances and for the directed design of humate-based products.

Identification of molecular targets and mechanism of action is always a challenge, in particular – for natural compounds due to inherent chemical complexity. BP-Cx-1 is a water-soluble modification of hydrolyzed lignin used as the platform for a portfolio of innovative pharmacological products aimed for therapy and supportive care of oncological patients. The present study describes a new approach, which combines in vitro screening of potential molecular targets for BP-Cx-1 using Diversity Profile - P9 panel by Eurofins Cerep (France) with a search of possible active components in silico in ChEMBL - manually curated chemical database of bioactive molecules with drug-like properties. The results of diversity assay demonstrate that BP-Cx-1 has multiple biological effects on neurotransmitters receptors, ligand-gated ion channels and transporters. Of particular importance is that the major part of identified molecular targets are involved in modulation of inflammation and immune response and might be related to tumorigenesis. Characterization of molecular composition of BP-Cx-1 with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and subsequent identification of possible active components by searching for molecular matches in silico in ChEMBL indicated polyphenolic components, nominally, flavonoids, sapogenins, phenanthrenes, as the major carriers of biological activity of BP-Cx-1. In vitro and in silico target screening yielded overlapping lists of proteins: adenosine receptors, dopamine receptor DRD4, glucocorticoid receptor, serotonin receptor 5-HT1, prostaglandin receptors, muscarinic cholinergic receptor, GABAA receptor. The pleiotropic molecular activities of polyphenolic components are beneficial in treatment of multifactorial disorders such as diseases associated with chronic inflammation and cancer.

Recent research has revealed that more than 1.3 billion tons of food is wasted globally every year. The disposal of such huge biomass has become a challenge. In the present paper, we report the production of the bio-oil by hydrothermal liquefaction of three classes of food waste: meat, cheese and fruits. The highest yield of the bio-oil was observed for meat (∼60%) and cheese (∼75%), while for fruits, it was considerably low (∼10%). The molecular composition of the obtained bio-oil was investigated using ultrahigh resolution Fourier Transform Ion Cyclotron Resonance mass spectrometry and was found to be similar to that obtained from algae. Several thousand heteroatom compounds (N, N2, ON2, etc. classes) were reliably identified from each sample. It was found that bio-oils produced from meat and cheese have many compounds (∼90%) with common molecular formulas, while bio-oil produced from fruits differs considerably (∼30% of compounds are unique).

We report synthesis and application of the novel carboxylated styrene for internal calibration of Fourier transform ion cyclotron resonance mass-spectra of humic substances. The calibrant was synthesized in five steps from acetylsalicylic acid (aspirin) followed by spontaneous polymerization of vinyl salicylic acid. Aromatic nature of the prepared polymer enabled its simultaneous analysis in the presence of the Suwannee River fulvic acid without using dual-spray approach. The major advantage of the calibrant proposed in this study is a lack of suppression of humic substances signals and maintenance of peak intensity distribution. The appropriate calibration resulted in an increased number of unambiguous identification in Suwannee River fulvic acid. Thanks to the higher mass accuracy, it was also possible to refine attribution of the CHOS species to hydrolysable tannins as opposed to the erroneous previous assignment to the condensed tannins.

The East Siberian Arctic Shelf (ESAS) is the broadest and shallowest continental shelf in the World Ocean. It is characterized by both the highest rate of coastal erosion and a large volume of riverine input of terrigenous dissolved organic matter (DOM). DOM plays a significant role in marine aquatic ecosystems. The colored (chromophoric) fraction of DOM (CDOM) directly affects the quantity and spectral quality of available light, thereby impacting both primary production and UV exposure in aquatic ecosystems. A multi-year study of DOM optical parameters and the spectral characteristics of the DOM chromophoric fraction were carried out in the vast ESAS in the summer-fall seasons. The spectral characteristics of CDOM were applied to identify different biogeochemical provinces in the surveyed area. The analysis of CDOM spectral characteristics showed that the major part of the Laptev and East Siberian Sea shelf (making up the ESAS) is influenced by terrigenous DOM with high aromaticity, stemming from riverine discharge. The atmospheric circulation regime is the dominant factor controlling CDOM spatial distribution on the ESAS. A western and an eastern regime of ESAS, separated around 165–170° E, were identified with distinctly different DOM optical properties. Strong correlation between DOC and CDOM concentrations in surface shelf waters influenced by terrigenous discharge indicates feasibility of estimating DOC content from the CDOM assessed in situ using a WETStar fluorometer. The direct estimation of optical characteristics of DOM in ESAS waters provided by this study will also be useful for validation and calibration of remote sensing data.

Humic acids (HA) are natural organic compounds that are important components of organic matter. The accumulation, distribution, and fate of tritium-labeled HA prepared from coal were analyzed using wheat (Triticum aestivum L.) seedlings. There was a period of rapid accumulation of HA followed by a slower one in the period from 1 to 24h. There was a significant decrease in HA accumulation at low temperature, indicating that the slower rate of HA accumulation represented a membrane-mediated process. HA distribution in plant tissues was analyzed using autoradiography. In all cases, HA concentration was considerably higher in the roots than in the shoots. Detailed examination of autoradiograms showed that there was preferential accumulation of HA in the apices of roots and shoots of wheat seedlings. Lipid fractions were extracted from seedlings and analyzed with thin layer chromatography and gas chromatography–mass spectrometry. These analyses revealed that labeled HA were present in the neutral lipid fraction consisting mainly of alkanes and alkenes, which are usually found in plant waxes, associated with the cuticle and suberized tissues. Based on these data, it is suggested that HA-derived hydrocarbons may be used in wax biosynthesis. This role could explain the mitigating activity of humic substances under stress conditions.

The problem of permeable reactive barrier (PRB) capture and release behavior is investigated by means of an approximate analytical approach exploring the invariance of steady-state solutions of the advection–dispersion equation to conformal mapping. PRB configurations considered are doubly-symmetric funnel-and-gate as well as less frequent drain-and-gate systems. The effect of aquifer heterogeneity on contaminant plume spreading is hereby incorporated through an effective transverse macro-dispersion coefficient, which has to be known. Results are normalized and graphically represented in terms of a relative capture efficiency M of contaminant mass or groundwater passing a control plane (transect) at a sufficient distance up-stream of a PRB as to comply with underlying assumptions. Factors of safety FS are given as the ratios of required capture width under advective–dispersive and purely advective transport for achieving equal capture efficiency M. It is found that M also applies to the release behavior down-stream of a PRB, i.e., it describes the spreading and dilution of PRB treated groundwater possibly containing incompletely remediated contamination and/or remediation reaction products. Hypothetical examples are given to demonstrate results.

The possible use of the concentration of intracellular adenosine triphosphate (ATP) as a parameter enabling quick and adequate evaluation of the metabolic activity of methanogenic cells was demonstrated in the work. This approach was used to analyze the effect of introducing potassium humate and fulvic acids (1&ndash, 10 g/L) into media with four different methanogenic consortia producing biogas. The ATP concentration was analyzed by the bioluminescent luciferin&ndash, luciferase method at the beginning and end of the process. During the entire process, the biogas composition, biogas efficiency, and the kinetics of methanogenesis in the presence of humic compounds were determined. The increase in the concentration of potassium humate led to a decrease in the overall energy status of the cells and reduced methanogenesis efficiency. However, fulvic acids introduced into the media stimulated methanogenesis in half of the tested consortia, which was accompanied by an increase in ATP concentration in cell samples. So, a positive correlation between the metabolic activity of cells in biogas formation and the concentration of ATP was observed. ATP concentration control appears to be an attractive tool for finding compounds that suppress methanogenesis in landfills.

Purpose Humic substances (HS) being natural polyelectrolyte macromolecules with complex and disordered molecular structures are a key component of the terrestrial ecosystem. They have remarkable influence on environmental behavior of iron, the essential nutrient for plants. They might be considered as environmental friendly iron deficiency correctors free of synthetic iron (III) chelates disadvantages. The main goal of this study was to obtain water-soluble iron-rich humic compounds (IRHCs) and to evaluate their efficiency as chlorosis correctors.

Mossbauer spectroscopy of frozen aqueous solutions was demonstrated as an efficient stepwise control technique in the new one-pot synthesis of biocompatible feroxyhyte (δ ′-FeOOH) nanoparticles in situ stabilized by humic substances. Formation of ultradispersed Fe(OH)2 as an intermediate product and its interaction with humic substances were ascertained. The interaction of the surface of Fe(OH)2 with humic substances was considered as a starting point in the mechanism of in situ stabilization and further growth control of humic-stabilized feroxyhyte nanoparticles.