Influence Of Fulvic Acid Research Articles

Photodegradation of γ-HCH by α-Fe 2O 3 and the influence of fulvic acid

The purpose of this study was to examine photodegradation of γ-hexachlorocyclohexane (γ-HCH) by α-Fe 2O 3 and the influence of fulvic acid (FA) in this photochemical process. A 300 W high-pressure mercury lamp was employed as the light source. The result showed that the UV light alone could play an important role in the degradation of γ-HCH. The presence of α-Fe 2O 3 was found to promote the photodegradation of γ-HCH. The photodegradation of γ-HCH by α-Fe 2O 3 follows pseudo-first-order reaction kinetics. The effect of the FA on the photodegradation of γ-HCH was also performed. The result revealed that the FA slowed the photodegradation rate of γ-HCH. Oxidation products were also identified by gas chromatography with a mass spectroscopy detector. This process is of interest in both a remedial process induced by iron oxides in natural water surfaces and α-Fe 2O 3-mediated photodegradation method for purifying natural water containing γ-HCH and humic substances.

Nitrite accumulation in an attapulgas clay biofilm reactor by fulvic acids

As a result of seriously polluted raw water sources, some water-treatment plants in China are intending to apply the biofilm process as a pretreatment prior to the traditional drinking water-treatment systems. These polluted raw waters contain higher total organic matter and ammonium than unpolluted waters. It has been reported that synthetic organic matter can cause nitrite accumulation. However, there have been few reports about the influence of fulvic acids on nitrification. Fulvic acids are the main part of the natural organic matter in waters, and nitrite is a toxic substance which has been paid attention to recently, especially in the treatment of drinking water, so it is necessary to study the effect of fulvic acids on the nitrification process. In this experiment, a so-called `attapulgas clay' biofilm reactor was set up, in which attapulgas clay was packed as the support medium for biological growth. After 40 days start-up, a multi-species biofilm developed in the reactor. The influence of fulvic acids on nitrite accumulation was investigated. Nitrite accumulation in the biofilm process was related to fulvic acids loadings. When the fulvic acids loading was less than 0.002 kg (TOC)/h·m 3, no nitrite build-up appeared; but when the loading was in the range of 0.002–0.02 kg (TOC)/h·m 3, nitrite built up and the concentration of nitrite could reach as high as 11.4 mg/l. When the loading was above 0.07 kg (TOC)/h·m 3, the nitrification process was completely inhibited.

Influence of fulvic acid on the collagen secretion of bovine chondrocytes in vitro.

High concentrations of fulvic acid and selenium deficiency in drinking water are the main causative factors of Kashin-Beck disease, an endemic degenerative chronic osteoarticular disorder found in China. The influence of fulvic acid on collagen secretion was investigated in articular chondrocyte cultures from bovine interphalangeal joints. Collagen secretion in 7-day-old chondrocyte monolayers was determined by measuring [3H]-proline incorporation into collagen macromolecules after a 24-h application in cultured supernatants. Additionally, collagen secretion was measured with a collagen assay based on a dye-binding method of soluble collagens. Both methods showed a dose-dependent increase of collagen secretion after treatment with fulvic acid. The collagen was identified by immunoblotting and immunocytochemistry as type II collagen. Fulvic acid also induced H2O2 production in cartilage cells. After co-incubation with catalase and fulvic acid, the cells secreted the same amount of H2O2 or collagen as the non-treated controls, indicating an influence of H2O2 on collagen secretion. Chondrocytes were then treated directly with H2O2. This led to increased collagen secretion showing a positive correlation with the concentration of H2O2 up to 1 pM H2O2. Larger amounts of H2O2 decreased collagen secretion. Effects of reactive oxygen species, such as lipid peroxidation or lactate dehydrogenase (LDH) release from damaged cells, were not inducable by fulvic acid (<10 ppm). Our results demonstrate a fulvic-acid-induced stimulation of collagen secretion into the supernatant by articular chondrocytes via physiological amounts of H2O2.

Influence of fulvic acid on transport of iron in soils and uptake by paddy seedlings

The influence of fulvic acid (FA) on the porous system self diffusion coefficient (Dp) of Fe in Calciorthent soils of Bihar, India, was determined with the half cell technique. Significantly higher values of Dp were observed when Fe was applied as Fe–FA to the soil compared to FeCl3. The capacity factor of Fe decreased considerably due to its complexation by fulvic acid, resulting in an increase in the Dp of Fe. The organic carbon content of the soils correlated positively with Dp of Fe while it showed a negative relationship with active CaCO3 and the clay content of soils. A soil culture system simulating acquisition of Fe by rice was developed to investigate transport of Fe from the soil solution to the surface of the plant roots through diffusion and mass flow. Mass flow contributed only 5–9% of the total Fe uptake by rice, with the remainder being ascribed to diffusion and root interception. A significant relationship ( r =0.96**) between Dp- and Fe-uptake by rice was observed. The uptake of Fe by the crop and the percentage of tissue iron content derived from fertilizer were higher in the case of Fe–FA in comparison with FeCl3, indicating the superiority of organically complexed Fe fertilizers over inorganic salts.

Interaction of Humic Substances with Organic Pollutants and its Influence on the Concentration of these Pollutants from Water

Abstract The influence of fulvic acids (FAs) and humic acids (HAs) of different origin on liquid-liquid and solid-phase extraction of hydrophobic organic compounds (HOCs) with broadly varying values of octanol-water partition coefficients Kow has been investigated. It is shown that the solubilization by dissolved FAs and HAs can lead to a significant decrease in recovery of some HOCs even from very dilute (10–20 mg/l) aqueous solutions of these acids. The results of these investigations and an analysis of the relevant literature data, demonstrate that the extent of solubilization of HOCs by humic substances is determined not only by Kow, but also by the specific structure of the HOCs. The hypothesis of the formation of intramolecular micelles (IMMs) by unaggregated FAs and HAs, and the partition of HOCs between water and the IMMs is put forward to explain the solubilization of HOCs.

Fate and effects of salicylic acid compounds in freshwater systems

The comparative fates and effects of salicylic acid (SA) and Na salicylate in algae ( Scenedesmus subspicatus, Monoraphidium minutum), in Lemna minor, and in Daphnia magna were examined. Test methods were principally based on the OECD testing guidelines with modifications in the procedures. The influence of fulvic acid (FA) on bioconcentration and on toxic effects was studied. FA addition significantly reduced the bioavailability of SA in L. minor and the algae species. SA was more toxic to Lemnaceae, algae, and daphnids than to its Na salt. Bioconcentration factors in S. subspicatus, M. minutum, and L. minor were about 10 3 in 72–96 hr. The reproducibility of D. magna was reduced by 38% at a concentration of 20 mg SA/liter.

Influence of fulvic acid on bacteriophage adsorption and complexation in soil

The effect of fulvic acid, the major fraction of natural soluble organic matter, on the adsorption of MS2 bacteriophage to soil was investigated in controlled laboratory experiments. Batch experiments together with scanning electron microscopy-energy-dispersive X-ray analysis showed that fulvic acid complexed phage, which prevented its adsorption to soil. Phage strongly adsorbed to soil in the absence of fulvic acid. Phage which was complexed with fulvic acid was not irreversibly inactivated and could become viable under proper conditions, illustrating the importance of assay and elution procedures in the recovery of virus from aqueous solutions.

Influence of fulvic acid on the removal of trace concentrations of cadmium(II), copper(II), and zinc(II) from water by alum coagulation

The effectiveness of Cu 2+, Cd 2+ and Zn 2+ removal from solution by alum coagulation was measured with fulvic acid present and absent. A factorial experimental design and analysis of variance were used to determine the effect on metal ion removal of the individual variables pH, metal ion concentration, alum concentration and fulvic acid concentration and their combinations. The variable levels model water treatment plant conditions. Metal ion losses up to 96% for Cu 2+. 59% for Cd 2+ and 82% for Zn z+ were measured in the presence of fulvic acid. In its absence the maximum metal ion losses observed were 93%, 14% and 53% for Cu 2+, Cd 2+ and Zn 2+ respectively. Fulvic acid enhances metal ion removal under most experimental conditions. The practical implication of the results is that strong complexes between natural water organic matter and metal ions enhance their removal by the alum coagulation process.

The influence of fulvic acid on the growth of violet root rot and white root rot fungi

The influence of fulvic acid on the growth of violet root rot and white root rot fungi