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Результаты 3881-3890 из 4,937
Geochemical distribution of major and trace elements in agricultural soils of Castilla-La Mancha (central Spain): finding criteria for baselines and delimiting regional anomalies Полный текст
2019
Bravo, Sandra | García-Ordiales, Efrén | García-Navarro, Francisco Jesús | Amorós, José Ángel | Pérez-de-los-Reyes, Caridad | Jiménez Ballesta, R. (Raimundo) | Esbrí, José María | García-Noguero, Eva María | Higueras, Pablo
Castilla-La Mancha (central Spain) is a region characterized by significant agricultural production aimed at high-quality food products such as wine and olive oil. The quality of agricultural products depends directly on the soil quality. Soil geochemistry, including dispersion maps and the recognition of baselines and anomalies of various origins, is the most important tool to assess soil quality. With this objective, 200 soil samples were taken from agricultural areas distributed among the different geological domains present in the region. Analysis of these samples included evaluation of edaphological parameters (reactivity, electrical conductivity, organic matter content) and the geochemistry of major and trace elements by X-ray fluorescence. The dataset obtained was statistically analyzed for major elements and, in the case of trace elements, was normalized with respect to Al and analyzed using the relative cumulative frequency (RCF) distribution method. Furthermore, the geographic distribution of analytical data was characterized and analyzed using the kriging technique, with a correspondence found between major and trace elements in the different geologic domains of the region as well as with the most important mining areas. The results show an influence of the clay fraction present in the soil, which acts as a repository for trace elements. On the basis of the results, of the possible elements related with clay that could be used for normalization, Al was selected as the most suitable, followed by Fe, Mn, and Ti. Reference values estimated using this methodology were lower than those estimated in previous studies.
Показать больше [+] Меньше [-]Method development for simultaneous determination of polar and nonpolar pesticides in surface water by low-temperature partitioning extraction (LTPE) followed by HPLC-ESI-MS/MS Полный текст
2019
de Barros, André Luis Correa | de Abreu, Cíntia Grossi | da Cunha, Camila Cristina Rodrigues Ferreira | da Silva Rodrigues, Daniel Aparecido | Afonso, Robson José de Cássia Franco | da Silva, Gilmare Antônia
During this research, chemometric approaches were applied for optimization of the low-temperature partitioning extraction (LTPE) for the simultaneous analysis of the pesticides: acephate, difenoconazole, fenamidone, fluazifop, fluazinam, methamidophos, and thiamethoxam from surface water samples and determination by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. It was used the 2³ full factorial and the Doehlert experimental designs. The extraction technique was optimized by evaluating the effects of the three variables: sample pH, ionic strength (addition of Na₂HPO₄), and organic solvent volume. Considering the interest to find an optimal condition for all analytes simultaneously, the best extraction parameters found were as follows: pH = 5.33, concentration of Na₂HPO₄ = 0.0088 mol L⁻¹ and organic phase volume = 4.5 mL. The optimized methodology showed LOD and LOQ levels from 0.33 to 8.13 ng L⁻¹ and from 1.09 to 26.84 ng L⁻¹, respectively. The recovery values ranged from 38.37 and 99.83% and the RSD values varied from 2.33 to 18.92%. The method was applied to surface water analysis sampled in areas with intensive agricultural practices in Ouro Branco City, Minas Gerais, Brazil. The difenoconazole was detected in concentrations between 12.53 and 94.76 ng L⁻¹.
Показать больше [+] Меньше [-]Understanding fungal potential in the mitigation of contaminated areas in the Czech Republic: tolerance, biotransformation of hexachlorocyclohexane (HCH) and oxidative stress analysis Полный текст
2019
Russo, Fabiana | Ceci, Andrea | Maggi, Oriana | Siciliano, Antonietta | Guida, Marco | Petrangeli Papini, Marco | Černík, Miroslav | Persiani, Anna Maria
The study of the soil microbial community represents an important step in better understanding the environmental context. Therefore, biological characterisation and physicochemical integration are keys when defining contaminated sites. Fungi play a fundamental role in the soil, by providing and supporting ecological services for ecosystems and human wellbeing. In this research, 52 soil fungal taxa were isolated from in situ pilot reactors installed to a contaminated site in Czech Republic with a high concentration of hexachlorocyclohexane (HCH). Among the identified isolates, 12 strains were selected to evaluate their tolerance to different isomers of HCH by using specific indices (Rt:Rc; T.I.) and to test their potential in xenobiotic biotransformation. Most of the selected taxa was not significantly affected by exposure to HCH, underlining the elevated tolerance of all the tested fungal taxa, and different metabolic intermediates of HCH dechlorination were observed. The oxidative stress responses to HCH for two selected species, Penicillium simplicissimum and Trichoderma harzianum, were investigated in order to explore their toxic responses and to evaluate their potential functioning in bioremediation of contaminated environments. This research suggests that the isolated fungal species may provide opportunities for new eco-friendly, integrated and cost-effective solutions for environmental management and remediation, considering their efficient adaptation to stressful conditions.
Показать больше [+] Меньше [-]An empirical evaluation of financial development-carbon footprint nexus in One Belt and Road region Полный текст
2019
Hafeez, Muhammad | Yuan, Chunhui | Sānval, K̲h̲uram Shahzād | Aziz, Babar | Iqbal, Kashif | Raza, Salman
The aspiration of study is to explore the financial development-carbon footprint nexus in One Belt and Road initiative (BRI) region utilizing the panel dataset from 1990–2017. The cross-sectional dependence tests and second-generation panel unit tests were applied to affirm the cross-section dependence and integration level. The panel regression estimators from the Driscoll-Kraay standard error method for robust estimators in the presence of cross-sectional dependence have been applied to compute the estimators concerning the financial development-carbon footprint nexus for One Belt and Road economies. The estimates infer that financial development, urban population, and FDI have an adverse effect on carbon footprint. Furthermore, economic growth and energy consumption pollute the environment by enhancing the carbon footprint. Based on findings, it infers that financial development is a potential instrument to keep the environment through financial reforms. The estimates signify that it is necessary to allocate resources for renewable energy, energy efficiency, and energy conservation projects in order to moderate environmental degradation.
Показать больше [+] Меньше [-]Intercomparison study on commonly used methods to determine microplastics in wastewater and sludge samples Полный текст
2019
Lares, Mirka | Ncibi, Mohamed Chaker | Sillanpää, Markus | Sillanpää, Mika
Intercomparison study on commonly used methods to determine microplastics in wastewater and sludge samples Полный текст
2019
Lares, Mirka | Ncibi, Mohamed Chaker | Sillanpää, Markus | Sillanpää, Mika
The harmonized procedures in terms of the sampling, sample treatment and identification of microplastics in different environmental samples are missing, which poses challenges to researchers to compare the results or to adopt ‘the most effective’ monitoring approach. Furthermore, in the related literature, the used procedures are rarely tested with spiked microplastics to predetermine their recovery rates. Without this knowledge, results should only be discussed as rough estimations of the real environmental concentrations of microplastics. In this study, six different methods previously used in microplastic studies of different media were tested with municipal wastewater and digested sludge samples, spiked with seven different types of plastic particles and fibres. Recovery rates, time consumption, advantages and disadvantages were assessed and most suitable treatment procedures (i.e. high recovery rates in short amount of time) were chosen for both wastewater and sludge. Suitability of staining with Rose Bengal was examined together with most efficient methods, but it did not improve the recovery of microplastics. In addition, the possible impacts of the treatments for identification with micro-Raman and FTIR microscope were assessed. Filtration with size fractioning was found to be the best method for both wastewater and sludge samples, with recovery rates of spiked microplastics around 91.4% and 92.9%, respectively.
Показать больше [+] Меньше [-]Intercomparison study on commonly used methods to determine microplastics in wastewater and sludge samples Полный текст
2019
Lares, Mirka | Ncibi, Mohamed Chaker | Sillanpää, Markus | Sillanpää, Mika
The harmonized procedures in terms of the sampling, sample treatment and identification of microplastics in different environmental samples are missing, which poses challenges to researchers to compare the results or to adopt ‘the most effective’ monitoring approach. Furthermore, in the related literature, the used procedures are rarely tested with spiked microplastics to predetermine their recovery rates. Without this knowledge, results should only be discussed as rough estimations of the real environmental concentrations of microplastics. In this study, six different methods previously used in microplastic studies of different media were tested with municipal wastewater and digested sludge samples, spiked with seven different types of plastic particles and fibres. Recovery rates, time consumption, advantages and disadvantages were assessed and most suitable treatment procedures (i.e. high recovery rates in short amount of time) were chosen for both wastewater and sludge. Suitability of staining with Rose Bengal was examined together with most efficient methods, but it did not improve the recovery of microplastics. In addition, the possible impacts of the treatments for identification with micro-Raman and FTIR microscope were assessed. Filtration with size fractioning was found to be the best method for both wastewater and sludge samples, with recovery rates of spiked microplastics around 91.4% and 92.9%, respectively.
Показать больше [+] Меньше [-]The impact of nanoparticles zero-valent iron (nZVI) and rhizosphere microorganisms on the phytoremediation ability of white willow and its response Полный текст
2019
Mokarram-Kashtiban, Sahar | Hosseini, Seyed Mohsen | Tabari Kouchaksaraei, Masoud | Younesi, Habibollah
Soil contaminated with heavy metals (HMs) is a serious problem throughout the world that threatens all living organisms in the soil. Therefore, large-scale remediation is necessary. This study investigated a new combination of remediation techniques on heavy metal contaminated soil, phytoremediation, and soil amendment with nano-sized zero-valent iron (nZVI) and rhizosphere microorganisms. White willow (Salix alba L.) was grown for 160 days in pots containing Pb, Cu, and Cd and amended with 0, 150, and 300 (mg kg⁻¹) of nZVI and rhizosphere microorganisms, including the arbuscular mycorrhizal fungus (AMF), Rhizophagus irregularis, and the plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens. The results showed that inoculation with PGPR and AMF, particularly dual inoculation, improved plant growth as well as the physiological and biochemical parameters of white willow, and increased the bioconcentration factor (BCF) of Pb, Cu, and Cd. The low dose of nZVI significantly increased the root length and the leaf area of the seedlings and increased the BCF of Cd. In contrast, the high dose of nZVI had negative effects on the seedlings growth and the BCF of Pb and Cu, about − 32% and − 63%, respectively. Our results demonstrate that nZVI at low doses can improve plant performance in a phytoremediation context and that the use of beneficial rhizosphere microorganisms can minimize nZVI stress in plants and make them less susceptible to stress even under high dose conditions.
Показать больше [+] Меньше [-]Effects of exogenous salicylic acid and pH on pathogenicity of biotrophy-associated secreted protein 1 (BAS1)-overexpressing strain, Magnaporthe oryzae Полный текст
2019
Yang, Jing | Wang, Yunfeng | Liu, Lin | Liu, Lina | Wang, Chunmei | Wang, Changmi | Li, Chengyun
Abiotic stress can influence the interactions between a pathogen and its host. In this paper, we analyzed the effects of salicylic acid (SA) and pH on the morphological development and pathogenicity of Magnaporthe oryzae, the pathogen that causes rice (Oryza sativa) blast. A strain of rice blast that overexpresses biotrophy-associated secreted protein 1 (BAS1) and a wild-type (WT) strain were pretreated with different levels of pH and different concentrations of SA to analyze M. oryzae colony growth, sporulation, spore germination, dry weight of hypha, and appressorium formation. Disease incidence and the expression of defense-related genes in infected rice were analyzed after pretreatment with pH 5.00 or pH 8.00 and 200 μM SA. The results showed that both SA and pH had some influence on morphological development, including sporulation and appressorium formation of the BAS1-overexpression strain. In the 200 μM SA pretreatment, there was a lower incidence of disease and higher expression levels of the rice defense-related genes PR1a, PAL, HSP90, and PR5 on leaves inoculated with the BAS1-overexpession strain compared with the WT strain, whereas, LOX2 appeared to be downregulated in the BAS1-overexpession strain compared with the WT. In both pH treatments, disease incidence and expression of HSP90 were higher and the expression of PR1a and PR10a and LOX2 and PAL was lower in leaves inoculated with the BAS1-overexpression strain compared with leaves inoculated with the WT strain. We conclude that SA and pH affect morphological development of the BAS1-overexpression blast strain, but that these factors have little influence on the pathogenicity of the strain, indicating that BAS1-overexpression may have enhanced the tolerance of this rice blast strain to abiotic stressors. This work suggests new molecular mechanisms that exogenous SA and pH affect the interactions between M. oryzae and rice.
Показать больше [+] Меньше [-]Short-term effects of ambient fine particulate air pollution on inpatient visits for myocardial infarction in Beijing, China Полный текст
2019
Wu, Yao | Li, Man | Tian, Yaohua | Cao, Yaying | Song, Jing | Huang, Zhe | Wang, Xiaowen | Hu, Yonghua
The effects of ambient fine particulate matter (PM₂.₅) on the incidence of myocardial infarction have been reported, but little is known about this association in China. We conducted a time-series study of ambient PM₂.₅ concentrations and inpatient visits for myocardial infarction in Beijing. A generalized additive model with a Poisson link was applied to estimate the percentage change in inpatient visits for myocardial infarction following a 10-μg/m³ increase in PM₂.₅ concentrations. A total of 15,432 inpatient visits for myocardial infarction were identified between January 1, 2010, and June 30, 2012. A 10-μg/m³ increase in PM₂.₅ concentrations was associated with a 0.46% (P ≤ 0.001) increase in daily inpatient visits for myocardial infarction. Males were more sensitive to the adverse effects, and the association was more significant during the warm season (May through October). Short-term exposure to PM₂.₅ was associated with increased risk of inpatient visits for myocardial infarction in Beijing. The findings may be useful in developing more accurate targeted interventions.
Показать больше [+] Меньше [-]Economic development and environmental sustainability—the case of foreign direct investment effect on environmental pollution in China Полный текст
2019
Haibo, Chen | Ayamba, Emmanuel Caesar | Agyemang, Andrew Osei | Afriyie, Stephen Owusu | Anaba, Aganda Oswin
This research reviews and analyses the environmental catastrophes in China with regard to its adherence of global environmental policies and practices. The research makes available evidence of the present policy regime and institutions, strategies for curbing emission, environmental legislations and regulations and measures to provide a sustainable environment for the present and future generations. This paper reviewed how the environment is affected by the emissions. The findings revealed that China adheres to global policies and practices. China also receives local and international support in terms of assistance in dealing with environmental challenges. It was also revealed that carbon dioxide was not included in the list of pollutants to be taxed by the environmental protection tax law. Furthermore, the government needs to be strict at the local and district levels in enforcing the law to ensure professionalism and attainment of set standards.
Показать больше [+] Меньше [-]Anaerobic ammonium oxidation coupled to ferric iron reduction in the sediment of a eutrophic lake Полный текст
2019
Yao, Zongbao | Wang, Fang | Wang, Chunliu | Xu, Huacheng | Jiang, Helong
Anaerobic ammonium oxidation coupled to ferric iron reduction (Feammox) has been assumed to play an important role in nitrogen removal from ecosystems. This study assessed the potential role of Feammox in nitrogen transformation in eutrophic lake sediment using an isotope tracing technique in sediment slurry incubation experiments. Feammox was discovered in eutrophic lake sediment. A significant correlation was found between Feammox rates and iron-reducing rates. Furthermore, the positive correlations between the abundance of iron-reducing bacteria (FeRB), such as Geobacteraceae spp. and Shewanella spp., and Feammox rates indicate that Feammox was mediated by FeRB. The potential rate of Feammox in the isotopic tracer incubation treatment was 0.23–0.43 mg N kg⁻¹ day⁻¹. The estimated nitrogen loss caused by Feammox accounts for 5.0–9.2% of the human-induced N input annually into the eutrophic lake. Feammox alone or coupled with anaerobic ammonium oxidation (anammox) and/or denitrification may have an essential role in the nitrogen cycle within eutrophic lake sediment.
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