The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Branka B Petkovic - One of the best experts on this subject based on the ideXlab platform.
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boron doped diamond electrode a prestigious unmodified carbon electrode for simple and fast determination of Bentazone in river water samples
Diamond and Related Materials, 2018Co-Authors: Sonja Jevtic, Anđela Stefanovic, Dalibor M Stankovic, Marija V Pergal, Aleksandra T Ivanovic, Anja Jokic, Branka B PetkovicAbstract:Abstract Bentazone (BZ) is selective contact-past herbicide with suspected reproductive toxicity potential for human due to possible contamination of ground and surface waters. This work presents simple, rapid, sensitive and accurate determination of Bentazone at unmodified boron-doped diamond electrode, using differential pulse voltammetry in Britton-Robinson buffer (pH 4, oxidation peak at 1.0 V). Under optimized DPV conditions linear calibration curve was obtained for range of 2 to 100 μM, with a detection limit of 0.5 μM. The effect of possible interfering agents is negligible, confirming good selectivity of the method. The method was successfully applied to determination of Bentazone in spiked river water samples. This electrochemical determination of Bentazone represents a favorable alternative to other used time-consuming and expensive analytical techniques and procedures.
Hansjorgen Albrechtsen - One of the best experts on this subject based on the ideXlab platform.
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importance of methane oxidation for microbial degradation of the herbicide Bentazone in drinking water production
Frontiers in Environmental Science, 2020Co-Authors: Mathilde Jorgensen Hedegaard, Manuela Anna Maria Schliemannhaug, Nikola Milanovic, Rasmus Boehansen, Hansjorgen AlbrechtsenAbstract:Bentazone is a herbicide, which is frequently detected in groundwater due to its mobility and persistence in aquifers. Groundwater is used as a drinking water source all over the world, and sustainable methods to remove pesticides at low concentrations are urgently needed since pesticide contaminations can adversely affect human health. The aim of this study was to investigate whether microbial Bentazone degradation was associated with methane oxidation in full-scale drinking water treatment plants. To this end, we investigated Bentazone biodegradation in microcosms with water and filter material from rapid sand filters, or biomass from aeration systems, and we investigated the statistical relation between the presence of methane and Bentazone in groundwater abstraction wells. An array of evidence supported an association between Bentazone degradation and methane oxidation in the biological treatment process. The biodegradation potential of Bentazone was associated with the presence of methane in the raw water at 14 different water works. In contrast, no association was observed with any of the other investigated inorganic energy sources, e.g. ammonium. Addition of acetylene inhibited methane oxidation and the Bentazone degradation in filter material from two investigated waterworks. Biomass from the aeration tanks degraded Bentazone, but only while oxidizing methane. Bentazone removal rates and methane removal rates correlated significantly across all the experiments with biomass or filter material, with an overall transformation yield of 15×10-5 moleBTZ/moleCH4. This demonstrated that the Bentazone degradation was conducted by the same type of process in all the investigated communities, governed by methane oxidation. Furthermore, based on more than 10.000 water analyses from waterworks abstraction wells in Denmark, Bentazone was detected significantly less frequent in wells with high methane concentrations (> 1 mg/L) than in wells without methane. This suggests that biological treatment of Bentazone contamination in drinking water may be achieved using methanotrophs.
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Microbial degradation pathways of the herbicide Bentazone in filter sand used for drinking water treatment
Environmental Science: Water Research & Technology, 2019Co-Authors: Mathilde Jorgensen Hedegaard, Carsten Prasse, Hansjorgen AlbrechtsenAbstract:The herbicide Bentazone is used extensively worldwide, and it is frequently detected in groundwater sources used for drinking water production. Previously, Bentazone has been shown to be biodegraded in filter sand from biological rapid sand filters at various waterworks. This untapped potential could be an inexpensive and sustainable alternative for the removal of trace organic contaminants. To study the fate of Bentazone in sand filters and to identify associated risks, degradation pathways in filter sand were identified and the toxicity of identified transformation products was evaluated using quantitative structure–activity relationship (QSAR) modelling. Bentazone degradation was investigated in microcosm experiments with filter sand, effluent water and Bentazone at elevated (5 mg L−1) and environmentally relevant concentrations (
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microbial degradation pathways of the herbicide Bentazone in filter sand used for drinking water treatment
Environmental Science: Water Research & Technology, 2019Co-Authors: Mathilde Jorgensen Hedegaard, Carsten Prasse, Hansjorgen AlbrechtsenAbstract:The herbicide Bentazone is used extensively worldwide, and it is frequently detected in groundwater sources used for drinking water production. Previously, Bentazone has been shown to be biodegraded in filter sand from biological rapid sand filters at various waterworks. This untapped potential could be an inexpensive and sustainable alternative for the removal of trace organic contaminants. To study the fate of Bentazone in sand filters and to identify associated risks, degradation pathways in filter sand were identified and the toxicity of identified transformation products was evaluated using quantitative structure–activity relationship (QSAR) modelling. Bentazone degradation was investigated in microcosm experiments with filter sand, effluent water and Bentazone at elevated (5 mg L−1) and environmentally relevant concentrations (<10 μg L−1). The investigations at elevated concentrations revealed up to 10 transformation products, suggesting three main biotransformation pathways: 1) oxidation of the isopropyl-moiety to the corresponding carboxylic acid, 2) oxidation of the aromatic ring leading to ring cleavage and subsequent decarboxylation reactions, and 3) N-methylation followed by oxidation to a carboxylic acid. At environmentally relevant concentrations, 92% of the initial Bentazone was removed within 13 days, and at this point only one transformation product, carboxy-Bentazone, could be detected in the water. QSAR-models considering both human and environmentally relevant endpoints showed that degradation in filter sand led to a detoxification of Bentazone. Initial oxidation processes followed by further degradation, and partial mineralization highlights the relevance of both methanotrophs and heterotrophs for the Bentazone degradation in rapid sand filters.
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evidence of co metabolic Bentazone transformation by methanotrophic enrichment from a groundwater fed rapid sand filter
Water Research, 2018Co-Authors: Mathilde Jorgensen Hedegaard, Helene Deliniere, Carsten Prasse, Arnaud Dechesne, Barth F Smets, Hansjorgen AlbrechtsenAbstract:Abstract The herbicide Bentazone is recalcitrant in aquifers and is therefore frequently detected in wells used for drinking water production. However, Bentazone degradation has been observed in filter sand from a rapid sand filter at a waterworks with methane-rich groundwater. Here, the association between methane oxidation and removal of Bentazone was investigated with a methanotrophic enrichment culture derived from methane-fed column reactors inoculated with that filter sand. Several independent lines of evidence obtained from microcosm experiments with the methanotrophic enrichment culture, tap water and Bentazone at concentrations below 2 mg/L showed methanotrophic co-metabolic Bentazone transformation: The culture removed 53% of the Bentazone in 21 days in presence of 5 mg/L of methane, while only 31% was removed in absence of methane. Addition of acetylene inhibited methane oxidation and stopped Bentazone removal. The presence of Bentazone partly inhibited methane oxidation since the methane consumption rate was significantly lower at high (1 mg/L) than at low (1 μg/L) Bentazone concentrations. The transformation yield of methane relative to Bentazone normalized by their concentration ratio ranged from 58 to 158, well within the range for methanotrophic co-metabolic degradation of trace contaminants calculated from the literature, with normalized substrate preferences varying from 3 to 400. High-resolution mass spectrometry revealed formation of the transformation products (TPs) 6-OH, 8-OH, isopropyl-OH and di-OH-Bentazone, with higher abundances of all TPs in the presence of methane. Overall, we found a suite of evidence all showing that Bentazone was co-metabolically transformed to hydroxy-Bentazone by a methanotrophic culture enriched from a rapid sand filter at a waterworks.
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stimulation of aerobic degradation of Bentazone mecoprop and dichlorprop by oxygen addition to aquifer sediment
Science of The Total Environment, 2014Co-Authors: Suzi Levi, Annemarie Hybel, Poul Logstrup Bjerg, Hansjorgen AlbrechtsenAbstract:Abstract In order to investigate aerobic degradation potential for the herbicides Bentazone, mecoprop and dichlorprop, anaerobic groundwater samples from two monitoring and three drinking water wells near a drinking water abstraction field in Nybolle, Denmark, were screened for their degradation potential for the herbicides. In the presence of oxygen 14 C-labelled Bentazone and mecoprop were removed significantly from the two monitoring wells' groundwater samples. Oxygen was added to microcosms in order to investigate whether different oxygen concentrations stimulate the biodegradation of the three herbicides in microcosms using groundwater and sandy aquifer materials. To maintain a certain oxygen concentration this level was measured from the outside of the bottles with a fibre oxygen meter using oxygen-sensitive luminescent sensor foil mounted inside the microcosm, to which supplementary oxygen was added. The highest oxygen concentrations (corresponding to 4–11 mg L − 1 ) stimulated degradation (a 14–27% increase for mecoprop, 3–9% for dichlorprop and 15–20% for Bentazone) over an experimental period of 200 days. Oxygen was required to biodegrade the herbicides, since no degradation was observed under anaerobic conditions. This is the first time Bentazone degradation has been observed in aquifer material at low oxygen concentrations (2 mg L − 1 ). The sediment had substantial oxygen consumption (0.92–1.45 O 2 g -1 dw over 200 days) and oxygen was depleted rapidly in most incubations soon after its addition, which might be due to the oxidation of organic matter and other reduced species such as Fe 2 + , S 2 − and Mn in sediment before the biodegradation of herbicides takes place. This study suggests that oxygen enhancement around a drinking water abstraction field could stimulate the bioremediation of diffuse source contamination.
Francois Beguin - One of the best experts on this subject based on the ideXlab platform.
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electrochemical regeneration of activated carbon cloth exhausted with Bentazone
Environmental Science & Technology, 2008Co-Authors: Conchi O Ania, Francois BeguinAbstract:: The electrochemical regeneration of an activated carbon cloth exhausted with a common herbicide (Bentazone) was investigated under different operating conditions. The reversibility of the desorption process was confirmed by monitoring the UV spectra of the solution while cathodic polarization is being applied. Neither nanotextural nor chemical changes are produced in the carbon cloth upon polarization in the absence of the adsorbate. Upon cathodic polarization of a carbon cloth working electrode preloaded with Bentazone, negative charges appear on the surface. A partial Bentazone desorption results from repulsive electrostatic interactions between the negative charges on the carbon cloth and Bentazone. When the electrode potential is below the thermodynamic value for cathodic decomposition of water, hydroxyl ions are liberated. Such ions provoke local pH changes that are responsible of the dissociation of Bentazone and carbon surface groups to their anionic form. As a consequence of the pH increase, an almost reversible desorption of Bentazone is observed. The effects of several operating parameters on the regeneration efficiency were evaluated. Higher regeneration efficiencies were attained under potentiostatic as compared to galvanostatic conditions, as OH- production strongly depends on the applied potential.
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mechanism of adsorption and electrosorption of Bentazone on activated carbon cloth in aqueous solutions
Water Research, 2007Co-Authors: Conchi O Ania, Francois BeguinAbstract:Abstract An electrochemical technique has been applied to enhance the removal of a common herbicide (Bentazone) from aqueous solutions using an activated carbon cloth as electrode. A pH increase from acidic to basic reduces the uptake, with capacities going from 127 down to 80 mg/g at pH 2 and 7, respectively. Increasing the oxygen content of the carbon cloth causes a decrease in the Bentazone loading capacity at all pH values. This indicates that adsorption is governed by both dispersive and electrostatic interactions, the extent of which is controlled by the solution pH and the nature of the adsorbent. Anodic polarization of the carbon cloth noticeably enhances the adsorption of Bentazone, to an extent depending on the current applied to the carbon electrode. The electrosorption is promoted by a local pH decrease provoked by anodic decomposition of water in the pores of the carbon cloth.
Sonja Jevtic - One of the best experts on this subject based on the ideXlab platform.
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boron doped diamond electrode a prestigious unmodified carbon electrode for simple and fast determination of Bentazone in river water samples
Diamond and Related Materials, 2018Co-Authors: Sonja Jevtic, Anđela Stefanovic, Dalibor M Stankovic, Marija V Pergal, Aleksandra T Ivanovic, Anja Jokic, Branka B PetkovicAbstract:Abstract Bentazone (BZ) is selective contact-past herbicide with suspected reproductive toxicity potential for human due to possible contamination of ground and surface waters. This work presents simple, rapid, sensitive and accurate determination of Bentazone at unmodified boron-doped diamond electrode, using differential pulse voltammetry in Britton-Robinson buffer (pH 4, oxidation peak at 1.0 V). Under optimized DPV conditions linear calibration curve was obtained for range of 2 to 100 μM, with a detection limit of 0.5 μM. The effect of possible interfering agents is negligible, confirming good selectivity of the method. The method was successfully applied to determination of Bentazone in spiked river water samples. This electrochemical determination of Bentazone represents a favorable alternative to other used time-consuming and expensive analytical techniques and procedures.
Damia Barcelo - One of the best experts on this subject based on the ideXlab platform.
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determination of two phototransformation products of Bentazone using quadrupole time of flight mass spectrometry
Analytical and Bioanalytical Chemistry, 2007Co-Authors: Manuela Peschka, Mira Petrovic, Thomas P Knepper, Damia BarceloAbstract:The transformation products 2-(isopropylcarbamoyl)phenylsulfamic acid and 2-(1-hydroxypropane-2-yl)-1,2-dihydroindazol-3-one could be determined during the photolysis of the herbicide Bentazone. Degradation experiments were carried out with different types of water in a natural sunlight simulating system. Besides the anticipated hydroxylated Bentazone, the second transformation product was identified by means of exact mass measurement using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/QqToF MS). Both phototransformation products occurred in all water types tested. The required irradiation time was matrix dependent. 2-(Isopropylcarbamoyl)phenylsulfamic acid was detected in a drainage channel in the Ebro river delta (Catalonia, Spain).
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comparative photodegradation rates of alachlor and Bentazone in natural water and determination of breakdown products
Environmental Toxicology and Chemistry, 1995Co-Authors: S Chiron, Damia Barcelo, Joaquin Abian, Marta Ferrer, Francisco Sanchezbaeza, Angel MesseguerAbstract:The photochemical degradation of the herbicides alachlor (2-chloro-2′,6′-diethyl-N-methoxymethylacetanilide) and Bentazone (3-isopropyl-(1H)-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide) in distilled water and in river water, under xenon arc lamp irradiation, was investigated. Analytical determinations were carried out by using a xenon arc photoreactor and online solid-phase extraction coupled to liquid-chromatography diode-array and liquid-chromatography mass-spectrometry detection systems. Photolysis experiments were performed at low concentration (20 μg/L), and the advantages of this methodology over conventional techniques are discussed. The photodegradation of alachlor and Bentazone is a process depending on the water type, humic substances, and pH. When using a solution of 4 mg/L of humic matter, the estimated alachlor and Bentazone half-lives were 84 and 150 min, respectively, using a total irradiance of 550 W/m2 in the range of 300 to 800 nm. The degradation of alachlor and Bentazone followed pseudo second- and first-order kinetics, respectively. The major photodegradation products of both herbicides were identified either by on-line solid-phase extraction (SPE)-liquid chromatography-thermospray mass spectrometry (LC/TSP-MS) or on-line-SPE-LC/TSP-tandem mass spectrometry (LC/TSP-MS/MS). In addition to that, a total of six transformation products of alachlor were synthesized in our laboratory and their MS spectra were compared with those of the breakdown products obtained. After photodegradation, a total of 14 photoproducts resulted from alachlor dechlorination with subsequent hydroxylation and cyclization processes. The two major photoproducts were identified as hydroxy-alachlor and 8-ethyl-1-methoxymethyl-4-methyl-2-oxo-1,2,3,4-tetrahydroquinone. No significant breakdown products of Bentazone could be identified.
