scholarly journals Interactions of hydrophobic metal complexes and their constituents with aquatic humic substances

2007 ◽  
Vol 4 (5) ◽  
pp. 323 ◽  
Author(s):  
Amiel Boullemant ◽  
Jean-Pierre Gagné ◽  
Claude Fortin ◽  
Peter G. C. Campbell
Keyword(s):  
Metal Complexes ◽  
Humic Substances ◽  
Natural Waters ◽  
Hydrophobic Interactions ◽  
Equilibrium Dialysis ◽  
Fulvic Acids ◽  
Suwannee River ◽  
Dissolved Humic Substances ◽  
Ph Range

Environmental context. Lipophilic metal complexes, because they can readily cross biological membranes, are especially bioavailable. However, in natural waters these complexes do not necessarily exist in a free state, i.e. they may bind to the organic matter (humic substances) that is present in natural waters. It follows that the in situ bioavailability of lipophilic metal complexes will tend to be less than that measured in simple laboratory experiments. Abstract. The ability of dissolved humic substances (HS: fulvic and humic acids) to complex cationic metals is well known, but their interactions with neutral lipophilic metal complexes are little understood. In the present study, we have examined the behaviour of two such complexes ( Cd  L 2 0 -->Cd L02: L = DDC = diethyldithiocarbamate, or L = XANT = ethylxanthate) in the presence of Suwannee River Humic and Fulvic acids. Interactions between the neutral complexes and the humic substances were assessed by excitation-emission matrix (EEM) fluorescence spectroscopy at pH 5.5 and 7.0, and by equilibrium dialysis experiments (500 Da cut-off). The EEM measurements were carried out by titrating the humic substances (6.5 mg C L–1) with Cd, in the absence or presence of ligand L (1 µM DDC or 100 µM XANT). Given the very high stability constants for the complexation of cadmium by DDC and XANT and the excess ligand concentration, virtually all (>96%) of the Cd added to the L + HS matrix was calculated to be present as the neutral Cd L 2 0 -->CdL20 complex over the entire pH range tested. For both humic substances, addition of DDC or XANT alone led to shifts in the fluorescence spectra at both pH values, indicating that the DDC– and XANT– anions likely interact by electrostatic or hydrogen bonding within the humic molecules. The subsequent addition of Cd to these L + HS systems resulted in a disproportionately large enhancement of the fluorescence intensities of individual EEM peaks, this fluorescence enhancement being only slightly decreased by the shift from pH 7.0 to 5.5. We interpret this enhancement as evidence that the two neutral complexes associate with the humic substances, presumably by forming ternary complexes (Ln-Cd-HS). Hydrophobic interactions between the humic substances and the neutral complexes may also contribute, but to a lesser extent, as demonstrated by partitioning calculations based on the lipophilicity of the neutral complexes. The association of the neutral complexes with Suwannee River Humic Acid was confirmed by dialysis experiments.

Bioavailability of a nonylphenol isomer in dependence on the association to dissolved humic substances

2004 ◽  
Vol 50 (5) ◽  
pp. 277-283 ◽  
Author(s):  
R. Vinken ◽  
A. Höllrigl-Rosta ◽  
B. Schmidt ◽  
A. Schäffer ◽  
P.F.-X. Corvini
Keyword(s):  
Humic Acid ◽  
Carbon Source ◽  
Humic Substances ◽  
Organic Compounds ◽  
Sole Carbon Source ◽  
Equilibrium Dialysis ◽  
Fulvic Acids ◽  
Degrading Bacterium ◽  
Bacterium Strain ◽  
Dissolved Humic Substances

Humic substances are important environmental components since they represent a very large part of organic compounds on earth. According to many reports, dissolved humic substances are a determinant parameter for the bioavailability of xenobiotic compounds. For the present bioavailability studies, two kinds of dissolved humic substances, a commercially available humic acid and fulvic acids isolated from peat were used. As the relevant xenobiotic, a defined branched nonylphenol isomer, 4(3′,5′-dimethyl-3′-heptyl)-phenol (p353NP) was synthesised according to Friedel-Crafts alkylation. Equilibrium dialysis studies were implemented in order to investigate the association between 14C-labelled p353NP and dissolved humic substances. The biodegradability in the presence of dissolved humic substances was examined in experiments with the nonylphenol degrading bacterium strain Sphingomonas TTNP3 and with p353NP as sole carbon source. The results showed that p353NP-humic acid associates were formed in high amounts, whereas no adducts with fulvic acids occurred. In the degradation studies with Sphingomonas TTNP3, no effects of dissolved humic substances on the bioavailability of p353NP could be observed. It was assumed that the association between nonylphenol and humic acids occurs rapidly and is reversible. Thus, the formation of "labile" complexes did not influence biodegradation rates, which were quite low.

scholarly journals Amphiphilic properties of humic substances in soils of the southern Vitim Plateau (Transbaikalia, Eastern Siberia)

2021 ◽  
Vol 908 (1) ◽  
pp. 012034
Author(s):  
E Yu Milkheev ◽  
Yu B Tsybenov
Keyword(s):  
Humic Substances ◽  
Hydrophobic Interactions ◽  
Multicomponent System ◽  
Hydrophobic Interaction Chromatography ◽  
Fulvic Acids ◽  
Eastern Siberia ◽  
Hydrophobic Properties ◽  
Hydrophobic Compounds ◽  
Acid Sample ◽  
Lower Capacity

Abstract Humic substances of soils are considered as a multicomponent system of amphiphilic (exhibiting both hydrophilic and hydrophobic properties) substances. Humic substances from soils of different genesis in the south of the Vitim Plateau (quasigley chernozem – Turbic Chernozem Molliglossic and brown soil – Stagnic Phaeozem Molliglossic) were studied. Using the hydrophobic interaction chromatography on Octyl-Sepharose® CL-4B, we separated a mixture of humic (HAs) and fulvic acids (FAs) due to their different ability to enter into hydrophobic interactions with the gel matrix. A higher percentage of hydrophobic compounds was revealed in HAs of quasigley chernozem, compared to HAs of brown soils, and FAs. The fulvic acid sample showed a lower capacity for hydrophobic interactions than the humic acid sample.

Role of dissolved humic substances surrogates on phthalate esters migration from sewage sludge

2008 ◽  
Vol 57 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Z. Zheng ◽  
P. J. He ◽  
H. Zhang ◽  
L. M. Shao
Keyword(s):  
Humic Substances ◽  
Phthalate Esters ◽  
Average Molecular Weight ◽  
Endocrine Disrupting Chemicals ◽  
Fulvic Acids ◽  
Facilitated Transport ◽  
Hydrophobic Property ◽  
Endocrine Disrupting ◽  
Dissolved Humic Substances ◽  
Ethylhexyl Phthalate

The facilitated transport of dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP), the priority endocrine disrupting chemicals in sludge, by dissolved humic substances (HS) was evaluated by batch extraction. The DBP, much less hydrophobic than DEHP, was inclined to migrate from sludge matrix into humic substances solutions, while the DEHP could not migrate facilitated by most humic and fulvic acids solutions, except the humic acid surrogate of high humification. This result revealed that the affinity of DEHP in sludge matrix exceeded DBP and was not susceptible by weak HS. The hydrophobic property controlled the association of phthalic acid esters on sludge residual phases. Migration rate of DBP was positively correlated to the weight-average molecular weight of HS surrogates and the aromatic extents of HA. Some functional groups in HS molecules benefited to the facilitated transport of DBP.

The fate of estrogenic compounds in the aquatic environment: sorption onto organic colloids

2003 ◽  
Vol 47 (9) ◽  
pp. 77-84 ◽  
Author(s):  
H. Yamamoto ◽  
H.M. Liljestrand
Keyword(s):  
Humic Acid ◽  
Fulvic Acid ◽  
Humic Substances ◽  
Alginic Acid ◽  
Fulvic Acids ◽  
Estrogenic Compounds ◽  
Treatment Processes ◽  
Suwannee River ◽  
Suwannee River Fulvic Acid ◽  
17Β Estradiol

In this study, sorption of some estrogens and estrogenic compounds onto several organic colloids was examined using fluorescence quenching techniques. Selected organic colloids included humic substances of several sources, Aldrich humic acid (AHA), Suwannee River humic acid (SRHA), Suwannee River fulvic acid (SRFA), and Nordic fulvic acid (NFA). Polysaccharides, alginic acid (AA) and dextran (Dex), and tannic acid (TA) were also selected. 17β-estradiol (E2), 17α-ethynylestradiol (EES), and estriol (E3) were selected as estrogens. Nonylphenol (NP), octylphenol (OP), and dibutylphthalate (DBP) were selected as estrogenic compounds. For most of the selected compounds, the sorption coefficients were in the order of TA > humic acids (SRHA or AHA) > fulvic acids (NFA or SRFA) > AA. The smallest or no significant sorption onto dextran was found for selected estrogens and estrogenic compounds. Comparing those compounds, neither a significant trend nor linear correlation with Log Kow was found. The resulting sorption coefficients for humic substances and TA suggested approximately 15 to 50% of the estrogens and estrogenic compounds were bound in typical natural water of 5 mgTOC/L and significant effects on the removal of them by water treatment processes, toxicity, or bioavailability were suggested.

scholarly journals In situ speciation measurements. Using diffusive gradients in thin films (DGT) to determine inorganically and organically complexed metals

2001 ◽  
Vol 73 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Hao Zhang ◽  
William Davison
Keyword(s):  
Thin Films ◽  
Humic Substances ◽  
Natural Waters ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
High Concentrations ◽  
Gel Composition ◽  
Diffusive Gradients ◽  
Good Agreement

The possibilities of using diffusive gradients in thin films (DGT) and anodic stripping voltammetry (ASV) to perform speciation measurements in natural waters are discussed. Both techniques measure labile species, but different approaches have been used to discriminate organic (Corg) and inorganic (Cinorg) metal complexes. In DGT, metals are bound to a resin after passing through a hydrogel that serves as a well-defined diffusion layer. DGT devices with different hydrogels that impede the diffusion of humic substances by different amounts were deployed in solutions of copper and humic substances. Devices with a gel composition that greatly restricted the diffusion of humic substances, but only retarded the diffusion of Cu ions slightly, could be used directly to determine Cinorg. By using different, more open pored gels, which allowed some passage of humic substances, it was possible to determine both Corg and Cinorg. The two separate measurements of Cinorg obtained using the two DGT approaches agreed well. At the high concentrations of Cu used there was good agreement with the predicted distribution from the speciation code WHAM. At the lowest Cu concentration, the proportion of Cinorg estimated using DGT was higher than with WHAM. Possibilities of errors in the DGT or modeling approaches are discussed.

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.

scholarly journals Organic Materials and Their Chemically Extracted Humic and Fulvic Acids as Potential Soil Amendments for Faba Bean Cultivation in Soils with Varying CaCO3 Contents

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 205
Author(s):  
Ihab M. Farid ◽  
Mohamed A. El-Ghozoli ◽  
Mohamed H. H. Abbas ◽  
Dalia S. El-Atrony ◽  
Hassan H. Abbas ◽  
...  
Keyword(s):  
Humic Substances ◽  
Faba Bean ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Organic Amendments ◽  
Fulvic Acids ◽  
Mineral N ◽  
Randomized Design ◽  
Long Time ◽  
Factor C

Organic amendments are important sources of nutrients that release upon organic matter degradation, yet the stability of these organics in arid and semi-arid regions is relatively low. In contrast, humic substances (HS) are resistant to biodegradation and can keep nutrients in the soil available for the plant over a long time. Combinations between humic substances (HS) and mineral-N fertilizers are assumed to retain higher available nutrients in soils than those recorded for the sole application of either mineral or organic applications. We anticipate, however, that humic substances might not be as efficient as the organics from which they were extracted in increasing NP uptake by plants. To test these assumptions, faba bean was planted in a pot experiment under greenhouse conditions following a complete randomized design while considering three factors: two soils (calcareous and non-calcareous, Factor A), two organics (biogas and compost, Factor B) and combinations of the organics and their extracts (HA or FA) together with complementary doses of mineral-N ((NH4)2SO4) to attain a total rate of 50 kg N ha−1 (the recommended dose for faba bean plants) (Factor C). Results indicated that nitrogenase activity increased significantly due to the application of the used organics. In this respect, compost manure caused higher nitrogenase activity than biogas manure did. Humic substances raised NP-availability and the uptake by plants significantly; however, the values of increase were lower than those that occurred due to the compost or biogas manure. Moreover, the sole application of the used organics recorded the highest increases in plant biomass. Significant correlations were also detected between NP-availability, uptake and plant biomass. This means that HS could probably retain nutrients in available forms for long time periods, yet nutrients released continuously but slowly upon decomposition of organics seemed more important for plant nutrition.

scholarly journals Toward Chalcogenide Platform Infrared Sensor Dedicated to the In Situ Detection of Aromatic Hydrocarbons in Natural Waters via an Attenuated Total Reflection Spectroscopy Study

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2449
Author(s):  
Marion Baillieul ◽  
Emeline Baudet ◽  
Karine Michel ◽  
Jonathan Moreau ◽  
Petr Němec ◽  
...  
Keyword(s):  
Natural Water ◽  
Natural Waters ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Infrared Sensor ◽  
Reflection Spectroscopy ◽  
Infrared Spectral ◽  
Micro Sensor ◽  
In Situ Detection

The objective of this study is to demonstrate the successful functionalization of the surface of a chalcogenide infrared waveguide with the ultimate goal of developing an infrared micro-sensor device. First, a polyisobutylene coating was selected by testing its physico-chemical compatibility with a Ge-Sb-Se selenide surface. To simulate the chalcogenide platform infrared sensor, the detection of benzene, toluene, and ortho-, meta- and para-xylenes was efficaciously performed using a polyisobutylene layer spin-coated on 1 and 2.5 µm co-sputtered selenide films of Ge28Sb12Se60 composition deposited on a zinc selenide prism used for attenuated total reflection spectroscopy. The thickness of the polymer coating was optimized by attenuated total reflection spectroscopy to achieve the highest possible attenuation of water absorption while maintaining the diffusion rate of the pollutant through the polymer film compatible with the targeted in situ analysis. Then, natural water, i.e., groundwater, wastewater, and seawater, was sampled for detection measurement by means of attenuated total reflection spectroscopy. This study is a valuable contribution concerning the functionalization by a hydrophobic polymer compatible with a chalcogenide optical sensor designed to operate in the mid-infrared spectral range to detect in situ organic molecules in natural water.

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