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PubMed2004

Kinetic and chemical assessment of the UV/H2O2 treatment of antiepileptic drug carbamazepine.

The UV/H2O2-induced degradation of carbamazepine, a worldwide used antiepileptic drug, recently found as contaminant in many municipal sewage treatment plant (STP) effluents and other aquatic environments, is investigated. The oxidation treatment caused an effective removal of the drug. At complete abatement of the substrate after 4 min treatment, a 35% value of removed total organic carbon (TOC) was obtained. A kinetic constant of (2.05+/-0.14) x 10(9) lmol(-1)s(-1) was determined for OH radical attack to carbamazepine in the UV/H2O2 process. Preparative TLC of the reaction mixture led to the isolation of acridine-9-carboxaldehyde as a reaction intermediate. HPLC and GC/MS analysis indicated formation of small amounts of acridine, salicylic acid, catechol and anthranilic acid among the reaction products. Under the same reaction conditions, synthetically prepared 10,11-epoxycarbamazepine was easily degraded to acridine as main product, suggesting that this epoxide is a likely intermediate in the oxidative conversion of carbamazepine to acridine. Under sunlight irradiation, carbamazepine in water underwent slow degradation to afford likewise acridine as main product. In view of the mutagenic properties of acridine, these results would raise important issues concerning the possible environmental impact of carbamazepine release through domestic wastewaters and support the importance of prolonged oxidation treatments to ensure complete degradation of aromatic intermediates.

Acridines↗

PubMed1998

Effects of dissolved organic matter (DOM) on the bioconcentration of organic chemicals in aquatic organisms--a review.

Current knowledge on the effects of dissolved organic matter (DOM) on the bioconcentration of organic chemicals in aquatic animals (water fleas, mussels, amphipods and fish) is summarized. A graphical representation of the available data gives an overview of the magnitude of the observed effects. Most of the studies have shown decreases in bioconcentration in the presence of DOM (2 to 98% relative to DOM-free controls). However, at low DOM levels, up to 10 mg/L, also enhancements of bioconcentration due to DOM, ranging from 2 to 303% have been reported. Generally, the change in BCFW (Bioconcentration factor on a wet weight basis) per mg/L DOC was most pronounced at low levels of DOC. The data also show that DOM from different sources with different characteristics and quality can lead to substantial variations in the bioconcentration of organic compounds at comparable levels of DOC. While decreases in bioconcentration have generally been attributed to a lack of bioavailability of DOM-bound chemical, no mechanisms have been proposed to explain increased uptake of xenobiotics caused by DOM.

Animals↗

PubMed1999

An experimental design to probe the interactions of dissolved organic matter and xenobiotics: bioavailability of pyrene and 2,2',5,5'-tetrachlorobiphenyl to Daphnia magna.

Experiments were conducted to probe the interactions between natural dissolved organic matter (DOM) and two xenobiotics, and to determine how DOM influences their bioavailability. The experimental set-up, using dialysis bags, was designed to expose test organisms to the same constant concentration of free dissolved chemical, while increasing the concentration of the bound-to-DOM fraction. Daphnia magna S. were exposed to pyrene or 2,2',5,5'-tetrachlorobiphenyl in the presence of 0, 1, 2, 5, 10 or 20 mg L(-1) of a reference riverine humic acid (Suwannee River Humic Acid). The physico-chemical parameters were well constrained in the microcosm, demonstrating its potential usefulness. However bioaccumulation by D. magna showed important variability between replicate treatments, sufficient to mask any trends as a function of DOM concentration. The organic-carbon-normalised partition coefficients (K(OC)) ranged from 52000 to 92000 L kg(-1) for pyrene and from 8200 to 89000 L kg(-1) for 2,2',5,5'-tetrachlorobiphenyl, with a marked "concentration effect" for the latter compound.

Animals↗

PubMed1999

The effect of humic acid on uptake/adsorption of copper by a marine bacterium and two marine ciliates.

The effect of humic acid (HA) on Cu uptake by a bacterium and two bacterivorus ciliates was investigated. The presence of HA resulted in a statistically significant (p<0.001) decrease in Cu associated with bacteria that were exposed to 67 microg Cu L(-1). Complexation of Cu appears to lower the availability of Cu with respect to bacterial cell surface binding and uptake. For ciliates, 10 mg HA L(-1) significantly reduced uptake of Cu by Uronema, but did not reduce uptake of Cu by Pleuronema. Uronema exposed to 67 microg Cu L(-1) accumulated 54% less Cu when 10 mg HA L(-1) was present (0.50 pg ciliate(-1) vs 0.23 pg ciliate(-1)). Uronema feeding on V. natriegens, took up less than half as much Cu as unfed Uronema when exposed to Cu without HA (0.41 pg Cu fed ciliate(-1) vs 0.86 pg Cu unfed ciliate(-1), but only 40% less when exposed to Cu and HA (0.31 pg Cu fed ciliate(-1) vs 0.51 pg Cu unfed ciliate(-1)). The lower % reduction attributable to fed ciliates in the presence of HA suggests that some of the Cu associated with HA is available through trophic processes.

Animals↗

PubMed1999

Biodeterioration of cardboard-based liquid containers collected for fibre reuse.

Liquid packaging board (LPB) collected in Germany is processed in Finland as recycled fibre and as plastic reject for incineration. The chemical, biological and physical changes occurring in recycled LPB bales were monitored during storage of six and 18 months. The moisture content in the core of the bales ranged from 7% to 53%, and pH values varied from 6.0 to 8.5. The average amount of mesophilic bacteria per container was 1.5 x 10(7) - 5 x 10(8), which means that recycled LPB pulp cannot be recommended for sanitary use. The concentration of CO2 inside the bale is an indicator of the activity of aerobic microorganisms and might be suitable for identifying deteriorated bales and removing them from the production line. Insects were found in some bales and the more deteriorated the bale was the more species of insects were found. The results showed the conversion of cellulose into humic acids to be clearly underway in some recycled LPB bales. The bale samples were extracted into hot water and into fulvic acids and humic acid (HA) fractions. The concentration of the humic acid fraction varied in the range 0.3-0.6% of the organic matter in fresh bales and 2.2% in one old bale. During aging nitrogen was enriched in all fractions.

Animals↗

PubMed1999

A model for the formation and degradation of bound residues of the herbicide 14C-isoproturon in soil.

The humic monomer catechol was reacted with 14C-isoproturon and some of its metabolites, including 14C-4-isopropylaniline, in aqueous solution under a stream of oxygen. Only in the case of 14C-4-isopropylaniline, incorporation in oligomers, in fulvic acid-like polymers, and in humic acid-like polymers was observed. The main oligomer was identified by mass spectrometry as 4,5-bis-(4-isopropylphenylamino)-3,5-cyclohexadiene-1,2-dione. Oligomers and polymers containing bound 14C-4-isopropylaniline were subjected to biodegradation studies in a loamy agricultural soil during 55 days by quantifying 14CO2 evolved. In all cases, significant mineralization rates could be determined, which, however, were much smaller than those of free 14C-4-isoproturon and free 14C-4-isopropylaniline in the same soil.

Biodegradation, Environmental↗

PubMed2000

Sorption of phenols to dissolved organic matter investigated by solid phase microextraction.

The sorption of phenol and different halogenated phenols to natural organic matter of a brown water lake (HO14), of a compost extract, of Aldrich humic acid (Aldrich-HA), and to the protein bovine serum albumin (BSA) was investigated using solid phase microextraction (SPME). The limit of determination for the SPME analysis was < 15 microg/l for all phenols investigated. The extraction coefficients K(F) were calculated according to a first-order extraction kinetics. In general, the extraction equilibrium was established faster due to the presence of dissolved organic matter (DOM). The highest sorption capacity of phenols was observed for BSA with log K(OC) values in the range between 2 and 6. For the compost extract and HO14 only a small sorption of the investigated phenols was determined. On the other hand, Aldrich humic acid showed a reasonable sorption of phenols with log K(OC) values between 2 and 3. The sorption to DOM decreased when the pH of the solution was increased.

Adsorption↗

PubMed2000

Short-term effects of biosolid and municipal solid waste applications on heavy metals distribution in a degraded soil under a semi-arid environment.

Digested biosolid (SS) and municipal solid waste (MSW) were surface-applied to a degraded carbonated soil, under semi-arid environment, at rates of 0 and 80 Mg/ha, to determine the changes in organic matter and in the distribution of heavy metals in the topsoil, 1 year after its application. Waste application slightly increased the organic matter content and improved the composition of humic fractions in the treated soils, mainly in the MSW amended plots. A sequential extraction method (Tessier et al., 1979) was used to determine the distribution of Cd, Cr, Cu, Ni, Pb and Zn in both the waste and the amended.soils. Waste application had little effect on the total concentration of Ni and Cr in the treated soils as a consequence of the low availability of these metals in the wastes. A considerable increase of Cd, Cu, Pb and Zn was observed as a consequence of the high content and/or high availability of these metals in the wastes. The more labile fraction (exchangeable fraction) of all metals studied increased slightly (< 1.5 mg/kg) when SS and MSW were added. However, a remarkable increase in the Fe/Mn oxide fraction of Cd, Cu and Pb and in the organic fraction of Zn were noted in treated plots, this increase being higher in the MSW treated soils.

Climate↗

PubMed2000

Aggregation studies of humic acid using multiangle laser light scattering.

An aqueous phase study of the naturally occurring dissolved organic carbon humic acid (HA) is performed using multiangle laser light scattering (MALLS) to measure its RMS radius and average molecular weight. A Zimm plot using Berry Formulism and a second-order fit gave an average molar mass of 1.164 x 10(8) g/mol and an average RMS radius (Rz) of 436.0 +/- 36 nm at 25 degrees C.

Environmental Monitoring↗

PubMed2001

Retrieval of water quality from airborne imaging spectrometry of various lake types in different seasons.

The suitability of the AISA airborne imaging spectrometer for monitoring lake water quality was tested in four surveys carried out in southern Finland in 1996-1998. Altogether, 11 lakes were surveyed and the total number of stations with concurrent remote sensing and limnological measurements was 127. The ranges of the water quality variables were: the sum of chlorophyll a and phaeophytin a 1-100 microg l(-1), turbidity 0.4-26 FNU, total suspended solids 0.7-32 mg l(-1), absorption coefficient of aquatic humus at 400 nm 1.2-14 m(-1) and secchi disc transparency 0.4-7 m. For the retrieval analyses, 24 AISA channels in the 450-786 nm range with a channel width of 6-14 nm were used. The agreement between estimated and observed water quality variables was generally good and R2 for the best algorithms was in the range of 0.72-0.90 over the whole dataset. The channels used for May were, in most cases, the same as those for August, but the empirical parameters of the algorithms were different. After seasonal grouping, R2 varied from 0.84 to 0.95. The use of apparent reflectance instead of radiance improved the estimation of water quality in the case of total suspended solids and turbidity. In the most humic lake, the empirical algorithms tested were suitable only for the interpretation of total suspended solids and turbidity.

Algorithms↗

PubMed2001

Inhibition of human plasmin activity using humic acids with arsenic.

In this study, we examined the effects of natural humic acid (HA) purified from drinking well-water in Blackfoot disease (BFD) endemic areas, using synthetic humic acid (SHA), such as protocatechuic acid, ferulic acid, vanillic acid or catechol, and trivalent arsenic on human plasmin activity. Data in this report indicated that both HA and SHA inhibited human plasmin activity by 20-80 and 5-95%, respectively, at concentrations of 20-480 microg/ml. Organometallic complexes composed of HA and arsenic show enhanced inhibition of plasmin activity as compared with either HA or arsenic alone. Monomers of HA or arsenic alone do not inhibit plasma activity. Oxidative stress may play a role in the inhibition of plasma activity, as various free-radical scavengers, such as ascorbic acid, alpha-tocopherol, catalase and superoxide dismutase (SOD), abrogate the inhibitory effects of HA and HA-arsenic complexes. The notion that HA/organometallic complexes (HA/OR) impaired plasmin activity was significant, due to the fact that both of these agents (HA and arsenic) are etiological factors in the development of peripheral vascular diseases, such as BFD. This report substantiates the inhibitory effects of HA/OR on plasmin activity, and thus provides evidence for the partial mechanism of action of HA/OR in BFD.

Arsenic↗

PubMed2003

Incorporation of (15)N-TNT transformation products into humifying plant organic matter as revealed by one- and two-dimensional solid state NMR spectroscopy.

Solid-state double cross polarization magic angle spinning (DCPMAS) 15N 13C nuclear magnetic resonance (NMR) spectroscopy was applied to study the incorporation of TNT transformation products into humifying plant organic matter. For this approach, 13C-enriched plant material (Lolium perenne) was mixed with quartz sand and aerobically incubated for 11 months after addition of 15N(3)-2,4,6-trinitrotoluene (TNT). After successive extraction of the incubate with water, methanol and ethyl acetate, approximately 60% of the 15N added as 15N(3)-TNT (15N(add)) remained in the solid organic residue (SOR-fraction). The acid insoluble fraction (AI) obtained after NaOH and HCl extractions contained approximately 20% of 15N(add). For both fractions, 15N NMR spectroscopy revealed an almost complete reduction of the TNT after 11 months of aerobic incubation. Most of the reduced nitrogen groups underwent further condensation. The corresponding DCPMAS NMR spectra allowed the identification of amides that are further substituted by alkyl groups that resist even acid hydrolysis. This assigns them to relatively stable compounds rather than to newly synthesized microbial peptides. The results of this study suggest further that the covalent binding of TNT transformation products to plant derived organic matter is mediated by alkylation and acetylation reactions, rather than by 1,4 addition of TNT-derived nitrogenous groups to quinones of the humic material.

Biotransformation↗

PubMed1997

Major origin of mutagenicity of chlorinated drinking water in China: humic acid or pollutants.

Since Loper and Glatz (J. Toxicol. Environ. Health, 4:919-938;1978) discovered the presence of the mutagenicity in drinking water after chlorination in 1978, humic acid (HA) has been considered as an important source. But our research results show that only 1/8 of observed direct frameshift mutagenicity in tap water originated from chlorination of HA isolated from raw water. Contamination from industrial waste and human settlement (night soil) are important potential sources of mutagenicity in chlorinated drinking water. The results show that mutagenicity from night soil after chlorination depended upon pH of sample. Production of mutagenicity at pH 6 is ten times of that at pH 8, and decomposition process is necessary condition for mutagenicity production. Season variation of mutagenicity of tap is also presented in the paper.

China↗

PubMed2002

The effect of humic acid on the adhesibility of neutrophils.

UNLABELLED: Humic acid (HA), a fluorescent allomelanin, has been implicated as an etiological agent of Blackfoot disease (BFD), a peripheral vascular disease prevailing in the southwest of Taiwan. Clinical and pathological studies reveal that it is similar to atherosclerosis. In this report, the effect of HA on human neutrophils is studied because prolonged and enhanced activation of neutrophils adhered on endothelium may damage the endothelium and initiate the process of thrombosis and vasculitis. METHODS: Neutrophils, treated with various concentrations of HA, were added to culture plates, cultured human umbilical vein endothelial cells (HUVECs), or human umbilical vein endothelium tissue culture for 15 or 30 min. The adhesion of neutrophils was measured qualitatively and quantitatively. The mechanism of neutrophil activation was studied with free radical production and various kinase measurements and their activities' assays. RESULTS: HA was shown to enhance, in a dose-dependent manner, the adhesion of neutrophils on the culture plates, cultured human umbilical vein endothelial cells, and human umbilical vein endothelium tissue culture. The adhesion-enhancing ability of HA is elicited through activation of ERK, P38 mitogen-activated kinase (P38MAPK), and phosphoinositide 3 kinase (PI3K) in neutrophils. HA also induces the NF-kappaB activation in neutrophils. CONCLUSION: HA treatment markedly enhanced adhesion and superoxide radical production of neutrophils, the characteristics of activated neutrophils; and all these stimulation effects were blocked by several kinase inhibitors, reflecting the involvement of the ERK, P38MAPK, and PI3K on the activation of neutrophils. The induction of NF-kappaB implied that the consequence of neutrophil activation by HA were similar to other stimulants. The prolonged neutrophil activation will further damage endothelium cell and cause thrombosis, vaculitis, as well as arteriosclerosis. This may partially explain why HA consumption will cause BFD.

Cell Adhesion↗

PubMed2005

Enrichment and isolation of ferric-iron- and humic-acid-reducing bacteria.

In anoxic habitats, ferric iron oxides and humic acids are widespread, and ferric-iron- and humic-acid-reducing microorganisms presumably play an important role in the oxidation of organic matter. Representative strains of ferric-iron- or humic-acid-reducing bacteria were isolated from a wide range of freshwater or marine environments. Most of them are strict anaerobes, and facultatively anaerobic microorganisms reduce ferric iron oxides or humic acids only after oxygen has been consumed. Hence, anaerobic techniques have to be used for the preparation of media as well as for the cultivation of microorganisms. Furthermore, special caution is needed in the preparation of ferric iron oxides and humic acids.

Bacteria, Anaerobic↗

PubMed2000

Interactions between dissolved petroleum hydrocarbons and pure and humic acid-coated mineral surfaces in artificial seawater.

The adsorption of total petroleum hydrocarbons (TPHs) on suspended particles in the marine environment is an important process affecting the fate of oils spilled in the ocean. Adsorption kinetics and adsorption isotherms of the water-soluble fraction of Fuel Oil No. 6 were performed on pure and humic acid-modified montmorillonite, alumina and kaolinite. The rates of adsorption on all sorbents are very fast and a pseudo-equilibrium is reached within 0.5 h. Linear adsorption isotherms were obtained for TPH and individual aromatic hydrocarbons on all sorbents. Higher sorption coefficients (Kd) were obtained for the humic acid-coated clays compared to the pure clays. However, a great contribution of mineral surface to overall adsorption was found on humic acid-modified particles in this study. A linear relationship between the log K and log Kow was also found for individual compounds on both pure alumina (log Km) and humic acid-coated alumina (log Koc).

Adsorption↗

PubMed2002

Influence of oligomeric silicic and humic acids on aluminum accumulation in a freshwater grazing invertebrate.

This study examined the influence of oligomeric silicic acid and humic acid on aluminum in the water column and its accumulation in the freshwater snail Lymnaea stagnalis. Forty-eight hours after addition of Al (500 microg L(-1)), 83% of the metal was lost from the water column. This loss was reduced by oligomeric silica (20 mg L(-1)) and by humic acid (10 mg L(-1)). Aluminum accumulated in the digestive gland and, to a lesser extent, in the remaining soft tissues, and this accumulation was reduced by oligomeric silica. In the presence of humic acid, Al accumulation in the digestive gland was unaffected, though less was accumulated in the remaining tissues. Snails accumulated Si preferentially in the digestive gland and this accumulation was increased in the presence of added Al. Thus, both oligomeric silica and humic acid influence Al bioavailability and Si is upregulated in the digestive gland in the presence of Al.

Aluminum↗

PubMed2001

Monitoring natural organic matter in water with scanning spectrophotometer.

This study uses scanning ultraviolet-visible (UV-Vis) spectrophotometer to monitor natural organic matter (NOM) in water. The results showed that the area under the UV-Vis spectra is a good surrogate to monitor the concentration of the aqueous NOM. No apparent difference was found between the spectra of the three commercially available humic acids used in this study. The use of the scanning spectra compensates the potential random error in the absorbance determined at single wavelength due to the heterogeneous NOM compositions. The major interference of the proposed method comes from the formazine turbidity and nitrate nitrogen (NO3- -N). Although filtration with a 0.45-microm filter can remove most of the interference from formazine, some interference is still present at a wavelength less than 250 nm. Also it is found that the presence of the NO3- -N greatly affect the spectra of the NOM. In order to monitor the NOM in water with minimized interference, it is recommended that the area under the spectra between 250 and 350 nm should be used as a surrogate for concentration of NOM in water.

Aza Compounds↗