Interaction of humic acid with chlorinated phenoxyacetic and benzoic acids.
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2,4-Dichlorophenoxyacetic Acid↗
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Results for “Humic Substances”
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Boundaries of ERTS and aircraft data within which useful water quality information can be obtained.
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Aircraft↗
Dissolved yellow organics: quantitative and qualitative aspects of extraction by four common techniques.
The dissolved yellow organic matter is removed from aliquots of the same freshwater sample by four common techniques: lyophilization, ion-exchange, ultrafiltration and organic solvent. Quantitative and qualitative aspects of the recovery, including fractionation by gel filtration and total nitrogen determinations, are presented.
Chemistry, Organic↗
The influence of some ecological factors on keratinophilic fungi in the soil.
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Animals↗
Humic acid-induced echinocyte transformation in human erythrocytes: characterization of morphological changes and determination of the mechanism underlying damage.
Blackfoot disease (BFD) is a peripheral arterial occlusive disease found among human inhabitants along the southwest coast of Taiwan. Well water used for drinking and cooking contains humic acid (HA), which may be a possible etiological factor. In this study, HA toxicity was investigated in human erythrocytes and was found to induce echinocytic formation. Morphological changes occurred in both a concentration- and time-dependent fashion. The presence of HA was also observed to facilitate the loading of erythrocytes with excess Ca(2+) (1 mM), which may have occurred following permeability changes in cell membranes, leading to echinocytic transformations. Sodium dodecyl sulfate (SDS) gel electrophoresis indicated that echinocyte formation was due to the oxidation of normal membrane proteins that were replaced by high-molecular-weight proteins. Humic acid also induced hemoglobin oxidation in erythrocytes. Data show that oxidative stress generated by HA as well as direct effects were exerted on the cytoskeleton of erythrocytes, and these may be significant factors in the etiology of BFD.
Anemia↗
Photochemical behavior of parathion in the presence of humic acids from different origins.
This paper reports the effect of ultraviolet radiation on the degradation of pesticide ethyl parathion in the presence of humic acids. Ethyl parathion was completely degraded in 300 min using an artificial lamp of 7.41 x 10(-10) einstein/s. Humic acid from peat did not influence the photochemical rate (k = 8.92 x 10(-3) min). However, in the presence of aquatic humic acid, the photochemical rate was higher (11.5 x 10(-3) min). The analytical determinations show the presence of p-nitrophenol and aminophenol in the reaction medium during the photochemical experiments. The kinetic of degradation in all experiments obeyed a first-order reaction pattern.
Biodegradation, Environmental↗
Reduced adsorption of ametryn in clay, humic acid, and soil by interaction with ferric ion under Fenton treatment conditions.
Previous work in our laboratory indicated a weak interaction between ferric ion and several triazine/triazinone herbicides during a Fenton treatment process, and the intensity of the interaction was calculated. To further support the existence of this weak interaction, the adsorption of ametryn, a triazine herbicide, was investigated in kaolinite clay, humic acid, and soil under pseudo-Fenton conditions. At a low addition rate of ferric ion, the adsorption of ametryn in clay, humic acid, and soil was enhanced due to the decreased pH resulting from the hydrolysis of ferric ion. But the pH effect was totally neutralized and the adsorption of ametryn was significantly reduced by further addition of ferric ion, demonstrating the existence of the weak interaction between ametryn and ferric acid. Further study showed that the adsorption-reduction effect of ferric ion existed not only with ametryn but also with several other triazine/triazinone herbicides. This weak interaction may accelerate the desorption process during the remediation of triazine/triazinone herbicide-contaminated soil using a Fenton/Fenton-like treatment, but it may also impede the degradation of these herbicides.
Adsorption↗
Influence of suspended clay minerals and humic matter on the solid phase extraction efficiency of selected pesticides from water.
The purpose of this investigation was to determine the influence of humic acids (HA) and Ca-montmorillonite (CaM) on the solid-phase extraction (SPE) efficiency of atrazine, alachlor and alpha-cypermethrin from water samples at various pH-values. The nature and intensity of binding of the studied pesticides to CaM were determined by X-ray diffraction analysis and termogravimetric analysis (TGA) test. The studied pesticides eluted from discs were analysed by thin-layer chromatography (TLC). The effects of CaM and humic acid were generally pH-dependent and acted independently in extraction efficiency influence. Lower recovery of pesticides was observed at higher pH values when CaM was > or =0.1 g and was attributed to greater dispersion of clay, increased surface area and subsequent adsorption. Concentrations of dissolved organic carbon (DOC) in humic acid had less effect on the extraction efficiency when water was at pH 8 compared to water at pH 2, which was probably due to greater nonpolar interactions of the pesticides to the charge-neutralized humic acid molecule.
Acetamides↗
Bacterial degradation of homo- and heterocyclic aromatic compounds in the presence of soluble/colloidal humic acid.
Aqueous association of several organic compounds to Aldrich humic acid (AHA) was determined by equilibrium dialysis or solubility enhancement. The effect of varying concentrations of AHA on chemical degradation was also determined in batch experiments. Atrazine and glucose mineralization was greater in the presence of AHA and the enhancement was attributed to enhanced cellular uptake. No AHA inhibition on naphthalene or quinoline biodegradation was observed.
Atrazine↗
Black shale as a sorbent for trichloroethylene and Cr(VI).
Black shale was examined as a natural sorbent for organic and inorganic contaminants. Trichloroethylene (TCE) could be removed well from the water by sorption onto the locally available black shale because of the high organic carbon content (5.2%) of the black shale in this study. Hexavalent chromium Cr(VI) was mainly removed by ionic sorption and reduction in batch and column experiments. Amphiphilic humic acid was also sorbed onto the black shale and could facilitate the sorption of TCE at the same time. Humic acid also enhanced the removal of Cr(VI) by reduction and sorption, but the amount of Cr(VI) adsorbed (mg kg(-1)) was smaller than that of TCE. Considering that the black shale in this study was used without any modifications and has a small surface area, black shale can be a cost-effective natural geosorbent and additive to remove organic contaminants and heavy metals.
Adsorption↗
Mobility of trace metals in retention pond sediments.
This paper presents the results of a study on trace metal mobility in the sediments of several road and urban infiltration/decantation ponds in France; the trace metal concentrations are indeed high. The potential mobility of trace metals (cadmium, nickel, chromium, copper, lead and zinc) was evaluated by application of the sequential extraction BCR protocol. Results have been compared with those from the IHSS protocol, which allows for the extraction of various forms of organic matter. Cadmium is the most easily exchangeable element in the case of variations in physical-chemical conditions (50% to 60% of Cd is exchangeable and 70% to 80% of Cd remains within the fulvic acid fraction) and is thus easily releasable within an acidic medium. Zinc is also potentially mobile and stays mainly concentrated in fulvic acids, except in the case of the Ronchin sediment (more than 50% in humin). In contrast, nickel and chromium are primarily present in the residual fraction and do not exhibit high mobility. Copper and lead are concentrated in both the humic acid fraction (IHSS protocol) and the organic phase (BCR scheme); consequently, their mobility is limited.
Cities↗
Effects of partial stone removal on the co-composting of olive-oil processing solid residues with poultry manure and the quality of compost.
Full scale composting studies were performed with stoned (SEOOPSW) and non stoned exhausted olive-oil processing solid waste (NSEOOPSW) mixed with 20% poultry manure to reach a C/N ratio of around 30 and to improve the chemical and microbiological properties of the end products. The experiment was performed on two windrows (3 m wide, 2.5 m high and 10 tonne weight) to investigate the effects of stone removal and poultry manure addition on composting process efficiency and on the quality of composts. The partially stone removal operation reduced the total composting time by at least one month compared with the untreated waste. The addition of poultry manure improved the chemical quality of the end product, as shown by the doubling of the nitrogen concentration after four months composting together with the increased amount of P and K. Compost from stoned exhausted olive-oil processing solid waste had higher levels of cation exchange capacity (CEC) and humic acid content with a lower [FA/HA] ratio indicating a high polymerisation level. Agronomic field test showed that both composts are not phytotoxic. When applied at the rate of 40 tonne ha(-1) to a potato culture, they produced approximately the same yield (46 and 48.5 tonne ha(-1)) but they acted differently in terms of plant development. Compost produced from the NSEOOPSW acted more positively on the stem length (84.1 against 77.6 cm) and on leaf weight (354 against 238 g), whereas compost from the SEOOPSW more positively affected tuber sizes (76% large grade compared to 55%).
Agriculture↗
Evaluation of organic matter and nutrient composition of partially decomposed and composted spent pig litter.
Characterization of soil-applied organic material is necessary in order to clarify the nature of the organic matterand nutrients in it. In this study, the organic matter and nutrient contents of the spent pig litter (a mixture of partially decomposed pig manure and sawdust) was characterized before and after windrow composting to: (1) determine their changes during composting, and (2) assess the suitability of the composted spent litter as a soil amendment. Results demonstrated that the time required to reach maturity, and the composition of composted spent litter, depended on the chemical properties of the initial compost feedstock as well as the compost strategies used during composting. Total N, P, and K concentrations of the composted litter depended on chemical properties of the initial material. On the other hand, C:N ratio, humic and fulvic acid and cation-exchange capacity were influenced by differences in composition of the initial spent litter and composting strategy. If moisture content was maintained weekly at 60% with a four-day turning frequency, the litter reached maturity in 56 days. Maturation of spent litter was accompanied by a decline in total C, water-extractable metals, NH(4)(+)-N, increase in ash, (NO(3)(-)+NO(2)(-)-N, humic acid, humic acid:fulvic acid ratio, and cation exchange capacity, and elimination of phytotoxicity. The stability of nutrient and organic matter, acceptable pH and electrical conductivity values, and low levels of undesirable components such as heavy metals and phytotoxic compounds of the spent litter provided substantial evidence that agronomically suitable compost can be obtained after composting in windrows.
Animals↗
HPSEC as a prepative fractionation technique for studies of natural organic matter (NOM).
High pressure size exclusion chromatography has been investigated as a preparative fractionation technique for studies of natural organic matter. Five different experiments were conducted to examine the effect of gel-solute interactions in the selected high pressure size exclusion chromatography system, and to evaluate the reproducibility of the method: (1) different flow rates (2) different sample concentrations, (3) reinjection of collected fractions, (4) addition of acetonitrile to the mobile phase, and (5) reinjection of hydrophobic and hydrophilic sub fractions. The results show that gel-solute interactions are a minor problem, and that the selected high pressure size exclusion chromatography system separates the natural organic matter molecules mainly on the basis of molecular size. The optical properties (ultraviolet/visible and fluorescence) vary systematically between the collected fractions. The main distinguishing features are relatively stronger absorbancies at shorter (<290 nm) wavelengths for smaller molecules, strong specific ultraviolet/visible absorbancy for natural organic matter molecules of intermediate molecular mass and very low fluorscence of larger molecules.
Absorption↗
Screening of four species of detritivorous (humus-former) earthworms for sustainable vermicomposting of paper waste.
Four specices of detritivorous (humus-former) earthworms were tested for their ability to vermicompost paper waste blended with cowdung in 6:1 (w/w) ratio. The anecic Lampito mauritii, Kinberg and the epigeic Eudrilus eugeniae, Kinberg were the most effective of the four species employed; 20 animals of each of these species generated castings amounting to about 52% of the feed mass (75 g) per fortnight. The performance of these two species was followed by the anecic Drawida willsi, Michaelsen and the epigeic Perionyx excavatus, Perrier; they achieved approximately 46% vermiconversion in comparable settings. The vermireactors were sustainable as the animals have remained consistently healthy and reproductive over a period of six months, and are continuing to remain so, turning in a steadily rising vermicast output. During this period E. eugeniae have grown to 2.3 times their original weight while the other three species have more than trebled their weights. The studies establish the feasibility of vermicomposting as a viable process for the gainful utilization of paper waste in an environmentally clean manner. They also indicate that all the four species of the worms screened by us are suitable for the process, with L. mauritii and E. eugeniae a shade more efficient than the other two species.
Animals↗
Extraction and characterization of organic matter from surface waters (reservoir of Keddara in Algeria).
The combined XAD-8 and XAD-4 resin procedure for isolating dissolved organic solutes from Keddara reservoir in Algeria was found to isolate 65% of total organic carbon (TOC). Of the 45% of solute adsorbed onto XAD-8 resin, 34% was in the form of fulvic acids, and 11% humic acids. Approximately 19% of the hydrophilic solutes were adsorbed onto XAD-4 resin. Characterization experiments have shown that the three isolated fractions have a low apparent molecular weight investigated by ultrafiltration and fluorescence and low aromaticity as shown by the results of UV-absorbance, the formation potential of total organic halogens (reactivity with chlorine) and the polyhydroxyaromatic (PHA) determined by pyrolysis gas chromatography/mass spectrometry (GC/MS) which show that the isolated fractions are aliphatic as well as aromatic. The low molecular weight and the low aromaticity compared with literature data are due to coagulation and sedimentation of NOM with high molecular weight, which occur naturally in the reservoir. The Keddara reservoir, with low hydraulic loading area and long detention times receiving water with low NOM and high in hardness can be expected to be very effective coagulation and sedimentation basins.
Benzopyrans↗
Maturity degree of composts from municipal solid wastes evaluated by differential scanning calorimetry.
Differential scanning calorimetry (DSC) in association with chemical analysis was applied to assess the maturity reached by the organic fraction of Municipal Solid Wastes (MSW) subjected to composting processes with manual and fixed aeration and sampled at different composting times. Thermograms showed that the difference in the treatments, i.e., the manual aeration and the fixed aeration, had no relevant effect on the stabilization and maturation of OM in the substrates. Common thermal effects observed were: a low temperature endotherm assigned to dehydration and/or loss of peripheral polysaccharides chains; a medium temperature exotherm assigned to loss of peptidic structures, and a high temperature exotherm assigned to oxydation and polycondensation of aromatic nuclei of the molecule. Results obtained suggest that in the experimental conditions used, a shorter time of composting (about 30 d) appears adequate, in order to limit the extended mineralization of OM, whereas a prolonged composting time (up to 132 d) would produce a compost of poor quality with high ash content and low OM content.
Biodegradation, Environmental↗
Trace metal sorption ability of insolubilized humic acids.
The objective of this work was to study the trace metal sorption ability of Insolubilized Humic Acids (IHA) in comparison with regular Humic Acids (HA). IHA were prepared from HA by heating at 330 degrees C for one hour under a nitrogen atmosphere. A solubility study was carried out at different pH values in NaNO3 (0.1 M) as a background electrolyte. It showed that IHA were insoluble until pH 10 whereas the solubility of HA increased with pH in one main step in the pH range 4-5 over which the soluble fraction of humic acids increased from 10% to 90%. We observed that trace metal sorption was dramatically influenced by these solubility properties. Indeed this study showed that above pH 5-6, HA and IHA may have opposite effects in terms of trace metal sorption. Solubilization of HA made possible the formation of soluble metal-humic complexes, retaining metal in solution even for pH at which hydroxide can form. Under such pH conditions, which very numerous soils show, HA could be involved in the transport and uptake of trace metals in the plant-soil system. In terms of remediation, HA are not a suitable binding phase. On the contrary IHA were not solubilized at neutral and alkaline pH, avoiding then the solubilization of sorbed trace metals. They appeared to be a suitable binding additive phase for future remediation trials.
Adsorption↗