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Resultados 1991-2000 de 3,197
Response of wheat and pea seedlings on increase of bromine concentration in the growth medium
2015
Shtangeeva, Irina | Niemelä, Matti | Perämäki, Paavo | Timofeev, Sergey
Biogeochemical cycles of bromine (Br) and its quantitative requirements for different plant species are still studied poorly. There is a need to examine Br pathways in plants and evaluate the factors important for Br accumulation in a plant. In the present work, the effects of different Br compounds on an uptake of Br by two plant species (wheat and pea) that tolerate Br differently (pea is more sensitive to Br compared with wheat) have been studied. The growth medium was spiked with either KBr or NaBr at concentrations 0, 10, 50 and 100 mg/L. Elemental analysis of the plants was performed using inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-MS analytical techniques after leaching of the samples with tetramethyl ammonium hydroxide at mild temperature (60 °C). The experimental results have shown that wheat and pea seedlings can accumulate rather large amounts of Br. An increase of Br concentration in a plant was not always directly proportional to the variations in the Br concentration in the growth medium. In wheat, the greater part of Br was accumulated during first 7 days. In pea, the uptake of Br lasted until the end of the experiment. Certain differences in the ability of plants to accumulate Br were observed when the plants were grown in a medium spiked with different Br compounds. In most cases, Br accumulation was higher in the leaves of the plants grown in the medium spiked with KBr. The same tendency was observed for another halogen, chlorine (Cl).
Mostrar más [+] Menos [-]Bacterial communities associated with aerobic degradation of polybrominated diphenyl ethers from river sediments
2015
Yang, Chu-Wen | Huang, Huang-Wen | Chao, Wei-Liang | Chang, Bea-Ven
Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants and have therefore drawn much environmental concern. We aimed to compare aerobic degradation of different PBDE congeners under various treatments and reveal the bacterial community associated with PBDE degradation in sediment. Results of this study indicate that degradation rates of BDE-15 were enhanced 45.1 and 81.3 % with the addition of suspended and microencapsulated Pseudomonas sp., respectively. However, the degradation rates of BDE-28, BDE-47, BDE-99, and BDE-100 did not differ among experimental treatments. Degradation rates of PBDE congeners were in the order of BDE-15 > BDE-28 > BDE-47 > BDE-99 > BDE-100. Using a pyrosequencing-based metagenomic approach, we found that addition of various treatments altered the microbial community composition in the sediment. Twenty-four bacterial genera associated with degradation of PBDEs; six are the core bacterial genera common among PBDE degraders. The diverse bacterial composition among different PBDE congener degradation indicates different combinations of bacteria involved in degradation of different PBDE congeners.
Mostrar más [+] Menos [-]Determination of selected pharmaceuticals in tap water and drinking water treatment plant by high-performance liquid chromatography-triple quadrupole mass spectrometer in Beijing, China
2015
Cai, Mei-Quan | Wang, Rong | Feng, Li | Zhang, Li-Qiu
A simultaneous determination method of 14 multi-class pharmaceuticals using solid-phase extraction (SPE) followed by high-performance liquid chromatography-tandem mass spectrometer (HPLC-MS/MS) was established to measure the occurrence and distribution of these pharmaceuticals in tap water and a drinking water treatment plant (DWTP) in Beijing, China. Target compounds included seven anti-inflammatory drugs, two antibacterial drugs, two lipid regulation drugs, one antiepileptic drug, and one hormone. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.01 to 1.80 ng/L and 0.05 to 3.00 ng/L, respectively. Intraday and inter-day precisions, recoveries of different matrices, and matrix effects were also investigated. Of the 14 pharmaceutical compounds selected, nine were identified in tap water of Beijing downtown with the concentration up to 38.24 ng/L (carbamazepine), and the concentration levels of detected pharmaceuticals in tap water (<5 ng/L for most pharmaceuticals) were lower than previous studies in other countries. In addition, ten and six pharmaceuticals were measured in raw water and finished water at the concentration ranged from 0.10 to 16.23 and 0.13 to 17.17 ng/L, respectively. Five compounds were detected most frequently in DWTP, namely antipyrine, carbamazepine, isopropylantipyrine, aminopyrine, and bezafibrate. Ibuprofen was found to be the highest concentration pharmaceutical during DWTP, up to 53.30 ng/L. DWTP shows a positive effect on the removal of most pharmaceuticals with 81.2–99.5 % removal efficiencies, followed by carbamazepine with 55.4 % removal efficiency, but it has no effect for removing ibuprofen and bezafibrate.
Mostrar más [+] Menos [-]The international environmental specimen banks—let’s get visible
2015
Küster, Anette | Becker, Paul R. | Kucklick, John R. | Pugh, Rebecca S. | Koschorreck, Jan
Environmental specimen banks (ESBs) are facilities that archive samples from the environment for future research and monitoring purposes. In addition, the long-term preservation of representative specimens is an important complement to environmental research and monitoring. Today, environmental specimen banking is experiencing a renaissance due to an increase in regulatory interest in ESB biota standards and trend data. The International Environmental Specimen Bank Group (IESB) promotes the worldwide development of techniques and strategies of environmental specimen banking and the international cooperation and collaboration among national ESBs. In order to provide a current and comprehensive overview on international environmental specimen banking activities, a questionnaire was sent to the national ESBs and asked for detailed information on the respective ESBs. The results show the rich diversity of national sampling programs, including more detailed information on archived samples, sampling strategies, and studies that have already been performed in the respective countries. All ESBs completing the survey expressed a strong interest in cooperating with other ESBs on a collaborative project. The collected information of national ESBs is intended to be made publicly available.
Mostrar más [+] Menos [-]Investigation of the interaction between As and Sb species and dissolved organic matter in the Yangtze Estuary, China, using excitation–emission matrices with parallel factor analysis
2015
Wang, Ying | Zhang, Di | Shen, Zhen-yao | Feng, Cheng-hong | Zhang, Xiao
The interactions between trivalent or pentavalent As/Sb and dissolved organic matter (DOM) in four regions (the river channel, the adjacent coastal area, and the northern and southern nearshore areas) of the Yangtze Estuary, China, were studied using fluorescence quenching titration combined with excitation–emission matrix spectroscopy and parallel factor analysis (PARAFAC). The As/Sb–DOM complexation characteristics were investigated using FTIR and UV absorbance spectroscopy and zeta potential analysis. Four protein-like components and one humic-like component were identified in the DOM from the Yangtze Estuary, China, by PARAFAC analysis. The tryptophan-like substance represented by component 2 was the dominant component and played an important role in the complexation between DOM and As/Sb. The results of complexation modeling demonstrated that the binding capacity of trivalent As/Sb with DOM was higher than that of pentavalent As/Sb with DOM. The DOM from the north nearshore area with the most acidic functional groups and greatest aromaticity possessed the highest binding capacity for trivalent and pentavalent As/Sb. The increase in the UV absorbance and the charge neutralization further indicated the interaction between As/Sb and DOM. The higher binding capacity of Sb(III) with DOM was mainly due to the hydroxyl and carboxyl groups. Our study demonstrates that the use of the advanced EEM–PARAFAC method in fluorescence quenching studies is very useful for evaluating the properties of DOM–pollutant interactions.
Mostrar más [+] Menos [-]Evaluating the potential of immobilized bacterial consortium for black liquor biodegradation
2015
Paliwal, Rashmi | Uniyal, Shivani | Rai, J. P. N.
Two indigenous bacterial strains, Bacillus megaterium ETLB-1 (accession no. KC767548) and Pseudomonas plecoglossicida ETLB-3 (accession no. KC767547), isolated from soil contaminated with paper mill effluent, were co-immobilized on corncob cubes to investigate their biodegradation potential against black liquor (BL). Results exhibit conspicuous reduction in color and lignin of BL upto 913.46 Co-Pt and 531.45 mg l⁻¹, respectively. Reduction in chlorophenols up to 12 mg l⁻¹was recorded with highest release of chloride ions, i.e., 1290 mg l⁻¹. Maximum enzyme activity for lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (LAC) was recorded as 5.06, 8.13, and 8.23 U ml⁻¹, respectively, during the treatment. Scanning electron microscopy (SEM) revealed successful immobilization of bacterial strains in porous structures of biomaterial. Gas chromatography/mass spectroscopy (GC/MS) showed formation of certain low molecular weight metabolites such as 4-hydroxy-benzoic acid, 3-hydroxy-4-methoxybenzaldehyde, ferulic acid, and t-cinnamic acid and removal of majority of the compounds (such as teratogenic phthalate derivatives) during the period of treatment. Results demonstrated that the indigenous bacterial consortium possesses excellent decolorization and lignin degradation capability which enables its commercial utilization in effluents treatment system.
Mostrar más [+] Menos [-]Amplified solubilization effects of inherent dissolved organic matter releasing from less-humified sediment on phenanthrene sorption
2015
Zhang, Xiaoyan | Wu, Yaoguo | Hu, Sihai | Lu, Cong | Zhang, Chengjun
Soil/sediment organic matter (SOM) releasing with inherent dissolved organic matter (DOM) formed in solution was confirmed both in rhizosphere sediment (S) and uncultivated sediment (P) water systems, and correlations between SOM characteristics subject to sediment’s humification degree and its releasing effects on phenanthrene sorption were emphasized. The sequential SOM releasing evidenced by fluorescence and ¹H-NMR profiles coupled with aqueous DOM solubilization was found to make sorption kinetics atypical and sorption capacity reduced, by comparing sorption results among sediments of different pretreatments. More importantly, the tested S was proved less humified with inherent DOM rich in microbial sources than P, and DOM affinity to phenanthrene was thus weakened (K dₒc values of 2.02–3.63 × 10⁴ L kg⁻¹), while the inhibitive effects of SOM releasing on sorption were strengthened, ascribing to the enlarged alterations of sediment characters, and particularly the amplified solubilization effects resulted from the larger proportion of soluble SOM and lower critical micelle concentration (5.66 mg L⁻¹) of DOM. Moreover, relative contribution of DOM solubilization to the releasing effects enhanced from 0.67 for P to 0.78 for S relative to alterations of sediment characters. Consequently, mobility and exposure risk of polycyclic aromatic hydrocarbons would be enhanced in a plant-soil/sediment-water system.
Mostrar más [+] Menos [-]Characterization of engineered TiO2 nanomaterials in a life cycle and risk assessments perspective
2015
Adam, Véronique | Loyaux-Lawniczak, Stéphanie | Quaranta, Gaetana
For the last 10 years, engineered nanomaterials (ENMs) have raised interest to industrials due to their properties. They are present in a large variety of products from cosmetics to building materials through food additives, and their value on the market was estimated to reach $3 trillion in 2014 (Technology Strategy Board 2009). TiO₂ NMs represent the second most important part of ENMs production worldwide (550–5500 t/year). However, a gap of knowledge remains regarding the fate and the effects of these, and consequently, impact and risk assessments are challenging. This is due to difficulties in not only characterizing NMs but also in selecting the NM properties which could contribute most to ecotoxicity and human toxicity. Characterizing NMs should thus rely on various analytical techniques in order to evaluate several properties and to crosscheck the results. The aims of this review are to understand the fate and effects of TiO₂ NMs in water, sediment, and soil and to determine which of their properties need to be characterized, to assess the analytical techniques available for their characterization, and to discuss the integration of specific properties in the Life Cycle Assessment and Risk Assessment calculations. This study underlines the need to take into account nano-specific properties in the modeling of their fate and effects. Among them, crystallinity, size, aggregation state, surface area, and particle number are most significant. This highlights the need for adapting ecotoxicological studies to NP-specific properties via new methods of measurement and new metrics for ecotoxicity thresholds.
Mostrar más [+] Menos [-]Use of EDTA in modified kinetic testing for contaminated drainage prediction from waste rocks: case of the Lac Tio mine
2015
Plante, Benoît | Benzaazoua, Mostafa | Bussière, Bruno | Kandji, El-Hadji-Babacar | Chopard, Aurélie | Bouzahzah, Hassan
The tools developed for acid mine drainage (AMD) prediction were proven unsuccessful to predict the geochemical behavior of mine waste rocks having a significant chemical sorption capacity, which delays the onset of contaminated neutral drainage (CND). The present work was performed in order to test a new approach of water quality prediction, by using a chelating agent solution (0.03 M EDTA, or ethylenediaminetetraacetic acid) in kinetic testing used for the prediction of the geochemical behavior of geologic material. The hypothesis underlying the proposed approach is that the EDTA solution should chelate the metals as soon as they are released by sulfide oxidation, inhibiting their sorption or secondary precipitation, and therefore reproduce a worst-case scenario where very low metal attenuation mechanisms are present in the drainage waters. Fresh and weathered waste rocks from the Lac Tio mine (Rio tinto, Iron and Titanium), which are known to generate Ni-CND at the field scale, were submitted to small-scale humidity cells in control tests (using deionized water) and using an EDTA solution. Results show that EDTA effectively prevents the metals to be sorbed or to precipitate as secondary minerals, therefore enabling to bypass the delay associated with metal sorption in the prediction of water quality from these materials. This work shows that the use of a chelating agent solution is a promising novel approach of water quality prediction and provides general guidelines to be used in further studies, which will help both practitioners and regulators to plan more efficient management and disposal strategies of mine wastes.
Mostrar más [+] Menos [-]Simultaneous detection of imidacloprid and parathion by the dual-labeled time-resolved fluoroimmunoassay
2015
Shi, Haiyan | Sheng, Enze | Feng, Lu | Zhou, Liangliang | Hua, Xiude | Wang, Minghua
A highly sensitive direct dual-labeled time-resolved fluoroimmunoassay (TRFIA) to detect parathion and imidacloprid simultaneously in food and environmental matrices was developed. Europium (Eu³⁺) and samarium (Sm³⁺) were used as fluorescent labels by coupling separately with L₁-Ab and A₁P₁-Ab. Under optimal assay conditions, the half-maximal inhibition concentration (IC₅₀) and limit of detection (LOD, IC₁₀) were 10.87 and 0.025 μg/L for parathion and 7.08 and 0.028 μg/L for imidacloprid, respectively. The cross-reactivities (CR) were negligible except for methyl-parathion (42.4 %) and imidaclothiz (103.4 %). The average recoveries of imidacloprid ranged from 78.9 to 104.2 % in water, soil, rice, tomato, and Chinese cabbage with a relative standard deviation (RSD) of 2.4 to 11.6 %, and those of parathion were from 81.5 to 110.9 % with the RSD of 3.2 to 10.5 %. The results of TRFIA for the authentic samples were validated by comparison with gas chromatography (GC) analyses, and satisfactory correlations (parathion: R ² = 0.9918; imidacloprid: R ² = 0.9908) were obtained. The results indicate that the dual-labeled TRFIA is convenient and reliable to detect parathion and imidacloprid simultaneously in food and environmental matrices.
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