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Biodegradation of diesel oil by a novel microbial consortium: comparison between co-inoculation with biosurfactant-producing strain and exogenously added biosurfactants Texto completo
2015
Mnif, Inès | Mnif, Sami | Sahnoun, Rihab | Maktouf, Sameh | Ayedi, Younes | Ellouze-Chaabouni, Semia | Ghribi, Dhouha
Bioremediation, involving the use of microorganisms to detoxify or remove pollutants, is the most interesting strategy for hydrocarbon remediation. In this aim, four hydrocarbon-degrading bacteria were isolated from oil-contaminated soil in Tunisia. They were identified by the 16S rDNA sequence analysis, as Lysinibacillus bronitolerans RI18 (KF964487), Bacillus thuringiensis RI16 (KM111604), Bacillus weihenstephanensis RI12 (KM094930), and Acinetobacter radioresistens RI7 (KJ829530). Moreover, a lipopeptide biosurfactant produced by Bacillus subtilis SPB1, confirmed to increase diesel solubility, was tested to increase diesel biodegradation along with co-inoculation with two biosurfactant-producing strains. Culture studies revealed the enhancement of diesel biodegradation by the selected consortium with the addition of SPB1 lipopeptide and in the cases of co-inoculation by biosurfactant-producing strain. In fact, an improvement of about 38.42 and 49.65 % of diesel degradation was registered in the presence of 0.1 % lipopeptide biosurfactant and when culturing B. subtilis SPB1 strain with the isolated consortium, respectively. Furthermore, the best improvement, evaluated to about 55.4 %, was recorded when using the consortium cultured with B. subtilis SPB1 and A. radioresistens RI7 strains. Gas chromatography analyses were correlated with the gravimetric evaluation of the residual hydrocarbons. Results suggested the potential applicability of the selected consortium along with the ex situ- and in situ-added biosurfactant for the effective bioremediation of diesel-contaminated water and soil.
Mostrar más [+] Menos [-]Airborne mineral components and trace metals in Paris region: spatial and temporal variability Texto completo
2015
Poulakis, E. | Theodosi, C. | Bressi, M. | Sciare, J. | Ghersi, V. | Mihalopoulos, N.
A variety of mineral components (Al, Fe) and trace metals (V, Cr, Mn, Ni, Cu, Zn, Cd, Pb) were simultaneously measured in PM₂.₅ and PM₁₀ fractions at three different locations (traffic, urban, and suburban) in the Greater Paris Area (GPA) on a daily basis throughout a year. Mineral species and trace metal levels measured in both fractions are in agreement with those reported in the literature and below the thresholds defined by the European guidelines for toxic metals (Cd, Ni, Pb). Size distribution between PM₂.₅ and PM₁₀ fractions revealed that mineral components prevail in the coarse mode, while trace metals are mainly confined in the fine one. Enrichment factor analysis, statistical analysis, and seasonal variability suggest that elements such as Mn, Cr, Zn, Fe, and Cu are attributed to traffic, V and Ni to oil combustion while Cd and Pb to industrial activities with regional origin. Meteorological parameters such as rain, boundary layer height (BLH), and air mass origin were found to significantly influence element concentrations. Periods with high frequency of northern and eastern air masses (from high populated and industrialized areas) are characterized by high metal concentrations. Finally, inner city and traffic emissions were also evaluated in PM₂.₅ fraction. Significant contributions (>50 %) were measured in the traffic site for Mn, Fe, Cr, Zn, and Cu, confirming that vehicle emissions contribute significantly to their levels, while in the urban site, the lower contributions (18 to 33 %) for all measured metals highlight the influence of regional sources on their levels.
Mostrar más [+] Menos [-]Urinary parabens and polyaromatic hydrocarbons independent of health conditions are associated with adult emotional support needs: USA NHANES, 2005–2008 Texto completo
2015
Shiue, Ivy
Everyone needs emotional support at some point in life, but the needs might not always be met. The present study was aimed to investigate the prevalence of unmet needs of emotional support in adults and to identify social, environmental and health attributes in a national and population-based setting in recent years. Data was retrieved from the US National Health and Nutrition Examination Surveys, 2005–2008, including demographics, blood pressure readings, self-reported emotional support needs in the last 12 months, self-reported ever health conditions and urinary environmental chemical concentrations. Statistical analyses included chi-square test, t test, survey-weighted logistic regression modeling and population attributable risk (PAR) estimation. Of 6733 American adults aged 40–80, 1273 (21.0 %) needed more emotional support in the past year. They tended to be aged 40–60, female, Mexican American, other Hispanic, education less than high school, or poverty income ratio 5+. People with higher levels of butyl paraben, ethyl paraben, methyl paraben, 1-hydroxynaphthalene, 2-hydroxynaphthalene, or 9-hydroxyfluorene (but not heavy metals, arsenic, phenols, phthalates, pesticides, or phytoestrogens) or historical diabetes, asthma, arthritis, stroke, thyroid disorder, chronic bronchitis, sleep complaint/disorder, or trouble seeing needed more emotional support. Significant risk associations from environmental chemicals mentioned above have remained after adjusting for historical health conditions as potential mediators. This is the first time examining prevalence of the unmet emotional support in adults and identifying the social, environmental and health attributes. Removal of parabens and polyaromatic hydrocarbons and increasing healthcare for people with health conditions to accommodate emotional support should be considered.
Mostrar más [+] Menos [-]Nonlinear QSAR modeling for predicting cytotoxicity of ionic liquids in leukemia rat cell line: an aid to green chemicals designing Texto completo
2015
Gupta, Shikha | Basant, Nikita | Singh, Kunwar P.
Safety assessment and designing of safer ionic liquids (ILs) are among the priorities of the chemists and toxicologists today. Computational approaches have been considered as appropriate methods for prior safety assessment of chemicals and tools to aid in structural designing. The present study is an attempt to investigate the chemical attributes of a wide variety of ILs towards their cytotoxicity in leukemia rat cell line IPC-81 through the development of nonlinear quantitative structure-activity relationship (QSAR) models in the light of the OECD principles for QSAR development. Here, the cascade correlation network (CCN), probabilistic neural network (PNN), and generalized regression neural networks (GRNN) QSAR models were established for the discrimination of ILs in four categories of cytotoxicity and their end-point prediction using few simple descriptors. The diversity and nonlinearity of the considered dataset were evaluated through computing the Euclidean distance and Brock-Dechert-Scheinkman statistics. The constructed QSAR models were validated with external test data. The predictive power of these models was established through a variety of stringent parameters recommended in QSAR literature. The classification QSARs rendered the accuracy of >86 %, and the regression models yielded correlation (R ²) of >0.90 in test data. The developed QSAR models exhibited high statistical confidence and identified the structural elements of the ILs responsible for their cytotoxicity and, hence, could be useful tools in structural designing of safer and green ILs.
Mostrar más [+] Menos [-]Indoor air quality in a restaurant kitchen using margarine for deep-frying Texto completo
2015
Sofuoglu, Sait C. | Toprak, Melis | Inal, Fikret | Cimrin, Arif H.
Indoor air quality has a great impact on human health. Cooking, in particular frying, is one of the most important sources of indoor air pollution. Indoor air CO, CO₂, particulate matter (PM), and volatile organic compound (VOC) concentrations, including aldehydes, were measured in the kitchen of a small establishment where a special deep-frying margarine was used. The objective was to assess occupational exposure concentrations for cooks of such restaurants. While individual VOC and PM₂.₅ concentrations were measured before, during, and after frying events using active sampling, TVOC, PM₁₀, CO, CO₂, temperature, and relative humidity were continuously monitored through the whole period. VOC and aldehyde concentrations did not increase to considerable levels with deep-frying compared to the background and public indoor environment levels, whereas PM₁₀ increased significantly (1.85 to 6.6 folds). The average PM₂.₅ concentration of the whole period ranged between 76 and 249 μg/m³. Hence, considerable PM exposures could occur during deep-frying with the special margarine, which might be sufficiently high to cause health effects on cooks considering their chronic occupational exposures.
Mostrar más [+] Menos [-]Changes in mesophyll element distribution and phytometabolite contents involved in fluoride tolerance of the arid gypsum-tolerant plant species Atractylis serratuloides Sieber ex Cass. (Asteraceae) Texto completo
2015
Boukhris, Asma | Laffont-Schwob, Isabelle | Rabier, Jacques | Salducci, Marie-Dominique | El Kadri, Lefi | Tonetto, Alain | Tatoni, Thierry | Chaieb, Mohamed
Atractylis serratuloides is an abundant native spiny species that grows in the surroundings of superphosphate factories in Tunisia. This plant species is adapted to arid environments and tolerates a high level of fluoride pollution in soils. The aim of this study was to better understand the physiological mechanisms of fluoride tolerance of this species, comparing the fluoride-contaminated sites of Gabes and Skhira with the reference site of Smara. Results demonstrated the involvement of leaf element and phytometabolite balances in the in situ response of A. serrulatoides to fluoride. Calcium, sulphur and magnesium were differently distributed between the sites of Gabes and Smara in all plant organs. No specific tissue fluorine accumulation in root, stem and leaf, even in the most contaminated site at Gabes, was detected by EDAX mapping. Lower anthocyan and flavonol levels but enhanced nitrogen balance index were found in A. serrulatoides leaves from Gabes compared to the two other sites. A. serratuloides appeared as a fluoride excluder and its tolerance involved calcium interactions with fluoride. Moreover, an occurrence of dark septate endophytes and arbuscular mycorhizal fungi in root systems of A. serratuloides was reported for the first time, and these symbioses were present but low at all sites. We suggest the use of this plant species for fluoride-polluted soil stabilization.
Mostrar más [+] Menos [-]Simulation of runoff and nutrient export from a typical small watershed in China using the Hydrological Simulation Program–Fortran Texto completo
2015
Li, Zhaofu | Liu, Hongyu | Luo, Chuan | Li, Yan | Li, Hengpeng | Pan, Jianjun | Jiang, Xiaosan | Zhou, Quansuo | Xiong, Zhengqin
The Hydrological Simulation Program-Fortran (HSPF), which is a hydrological and water-quality computer model that was developed by the United States Environmental Protection Agency, was employed to simulate runoff and nutrient export from a typical small watershed in a hilly eastern monsoon region of China. First, a parameter sensitivity analysis was performed to assess how changes in the model parameters affect runoff and nutrient export. Next, the model was calibrated and validated using measured runoff and nutrient concentration data. The Nash–Sutcliffe efficiency (E NS) values of the yearly runoff were 0.87 and 0.69 for the calibration and validation periods, respectively. For storms runoff events, the E NS values were 0.93 for the calibration period and 0.47 for the validation period. Antecedent precipitation and soil moisture conditions can affect the simulation accuracy of storm event flow. The E NS values for the total nitrogen (TN) export were 0.58 for the calibration period and 0.51 for the validation period. In addition, the correlation coefficients between the observed and simulated TN concentrations were 0.84 for the calibration period and 0.74 for the validation period. For phosphorus export, the E NS values were 0.89 for the calibration period and 0.88 for the validation period. In addition, the correlation coefficients between the observed and simulated orthophosphate concentrations were 0.96 and 0.94 for the calibration and validation periods, respectively. The nutrient simulation results are generally satisfactory even though the parameter-lumped HSPF model cannot represent the effects of the spatial pattern of land cover on nutrient export. The model parameters obtained in this study could serve as reference values for applying the model to similar regions. In addition, HSPF can properly describe the characteristics of water quantity and quality processes in this area. After adjustment, calibration, and validation of the parameters, the HSPF model is suitable for hydrological and water-quality simulations in watershed planning and management and for designing best management practices.
Mostrar más [+] Menos [-]Global sensitivity analysis for an integrated model for simulation of nitrogen dynamics under the irrigation with treated wastewater Texto completo
2015
Sun, Huaiwei | Zhu, Yan | Yang, Jinzhong | Wang, Xiugui
As the amount of water resources that can be utilized for agricultural production is limited, the reuse of treated wastewater (TWW) for irrigation is a practical solution to alleviate the water crisis in China. The process-based models, which estimate nitrogen dynamics under irrigation, are widely used to investigate the best irrigation and fertilization management practices in developed and developing countries. However, for modeling such a complex system for wastewater reuse, it is critical to conduct a sensitivity analysis to determine numerous input parameters and their interactions that contribute most to the variance of the model output for the development of process-based model. In this study, application of a comprehensive global sensitivity analysis for nitrogen dynamics was reported. The objective was to compare different global sensitivity analysis (GSA) on the key parameters for different model predictions of nitrogen and crop growth modules. The analysis was performed as two steps. Firstly, Morris screening method, which is one of the most commonly used screening method, was carried out to select the top affected parameters; then, a variance-based global sensitivity analysis method (extended Fourier amplitude sensitivity test, EFAST) was used to investigate more thoroughly the effects of selected parameters on model predictions. The results of GSA showed that strong parameter interactions exist in crop nitrogen uptake, nitrogen denitrification, crop yield, and evapotranspiration modules. Among all parameters, one of the soil physical-related parameters named as the van Genuchten air entry parameter showed the largest sensitivity effects on major model predictions. These results verified that more effort should be focused on quantifying soil parameters for more accurate model predictions in nitrogen- and crop-related predictions, and stress the need to better calibrate the model in a global sense. This study demonstrates the advantages of the GSA on a more complete analysis of model input parameters and their interactions on the model output for nitrogen modeling.
Mostrar más [+] Menos [-]Time-dependent expression and activity of cytochrome P450 1s in early life-stages of the zebrafish (Danio rerio) Texto completo
2015
Bräunig, Jennifer | Schiwy, Sabrina | Broedel, Oliver | Muller, Yvonne | Frohme, Marcus | Hollert, Henner | Keiter, Steffen H.
Zebrafish embryos are being increasingly used as model organisms for the assessment of single substances and complex environmental samples for regulatory purposes. Thus, it is essential to fully understand the xenobiotic metabolism during the different life-stages of early development. The aim of the present study was to determine arylhydrocarbon receptor (AhR)-mediated activity during selected times of early development using qPCR, enzymatic activity through measurement of 7-ethoxyresorufin-O-deethylase (EROD) activity, and protein expression analysis. In the present study, gene expression of cyp1a, cyp1b1, cyp1c1, cyp1c2, and ahr2 as well as EROD activity were investigated up to 120 h postfertilization (hpf) after exposure to either β-naphthoflavone (BNF) or a polycyclic aromatic hydrocarbons (PAH)-contaminated sediment extract from Vering Kanal in Hamburg (VK). Protein expression was measured at 72 hpf after exposure to 20 μg/L BNF. Altered proteins were identified by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting. Distinct patterns of basal messenger RNA (mRNA) expression were found for each of the cyp1 genes, suggesting specific roles during embryonic development. All transcripts were induced by BNF and VK. ahr2 mRNA expression was significantly upregulated after exposure to VK. All cyp1 genes investigated showed a temporal decline in expression at 72 hpf. The significant decline of Hsp 90β protein at 72 hpf after exposure to BNF may suggest an explanation for the decline of cyp1 genes at this time point as Hsp 90β is of major importance for the functioning of the Ah-receptor. EROD activity measured in embryos was significantly induced after 96 hpf of exposure to BNF or VK. Together, these results demonstrate distinct temporal patterns of cyp1 genes and protein activities in zebrafish embryos as well as show a need to investigate further the xenobiotic biotransformation system during early development of zebrafish.
Mostrar más [+] Menos [-]Effect of grain size and heavy metals on As immobilization by marble particles Texto completo
2015
Simón, M. | García, I. | González, V. | Romero, A. | Martin, F.
The effect of grain size and the interaction of heavy metals on As sorption by marble waste with different particle sizes was investigated. Acidic solutions containing only arsenic and a mixture of arsenic, lead, zinc, and cadmium were put in contact with the marble waste. The amount of metal(loid)s that were immobilized was calculated using the difference between the concentration in the acidic solution and in the liquid phase of the suspensions. Approximately 420 μg As m⁻²was sorbed onto the marble grains, both nonspecifically and specifically, where ≥80 % of the total arsenic in the acidic solution remained soluble, which suggests that this amendment is not effective to immobilize arsenic. However, in mixed contamination, relatively stable Pb-Ca arsenates were formed on the surface of the marble particles, and the soluble arsenic was reduced by 95 %, which indicates that marble particles can effectively immobilize arsenic and lead when both appear together.
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