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Результаты 1591-1600 из 4,086
Purification and characterization of biosurfactant produced by Bacillus licheniformis Y-1 and its application in remediation of petroleum contaminated soil Полный текст
2016
Liu, Boqun | Liu, Jinpeng | Ju, Meiting | Li, Xiaojing | Yu, Qilin
In our previous research, a petroleum degrading bacteria strain Bacillus licheniformis Y-1 was obtained in Dagang Oilfield which had the capability of producing biosurfactant. This biosurfactant was isolated and purified in this work. The biosurfactant produced by strain Y-1 had the capability to decrease the surface tension of water from 74.66 to 27.26mN/m, with the critical micelle concentration (CMC) of 40mg/L. The biosurfactant performed not only excellent stabilities against pH, temperature and salinity, but also great emulsifying activities to different kinds of oil, especially the crude oil. According to the results of FT-IR spectrum and 1H NMR spectrum detection, the surfactant was determined to be a cyclic lipopeptide. Furthermore, through the addition of surfactant, the effect of petroleum contaminated soil remediation by fungi got a significant improvement.
Показать больше [+] Меньше [-]Direct evidences on bacterial growth pattern regulating pyrene degradation pathway and genotypic dioxygenase expression Полный текст
2016
Chen, Baowei | Huang, Jinyin | Yuan, Ke | Lin, Li | Wang, Xiaowei | Yang, Lihua | Luan, Tiangang
Pyrene degradation by Mycobacterium sp. strain A1-PYR was investigated in the presence of nutrient broth, phenanthrene and fluoranthene, respectively. Fast bacterial growth in the nutrient broth considerably enhanced pyrene degradation rate, whereas degradation efficiency per cell was substantially decreased. The addition of nutrient broth could not alter the transcription levels of all dioxygenase genotypes. In the PAH-only substrates, bacterial growth completely relied on biological conversion of PAHs into the effective carbon sources, which led to a higher degradation efficiency of pyrene per cell than the case of nutrient broth. Significant correlations were only observed between nidA-related dioxygenase expression and pyrene degradation or bacterial growth. The highest pyrene degradation rate in the presence of phenanthrene was consistent with the highest transcription level of nidA and 4,5-pyrenediol as the sole initial metabolite. This study reveals that bacterial growth requirement can invigorate degradation of PAHs by regulating metabolic pathway and genotypic enzyme expression.
Показать больше [+] Меньше [-]Dynamic fugacity model for accidental oil release during Arctic shipping Полный текст
2016
Afenyo, Mawuli | K̲h̲ān, Faiṣal | Veitch, Brian | Yang, Ming
Improved understanding of ecological risk associated with Arctic shipping would help advance effective oil spill prevention, control, and mitigation strategies. Ecological risk assessment involves analysis of a release (oil), its fate, and dispersion, and the exposure and intake of the contaminant to different receptors. Exposure analysis is a key step of the detailed ecological risk assessment, which involves the evaluation of the concentration and persistence of released pollutants in the media of contact. In the present study, a multimedia fate and transport model is presented, which is developed using a fugacity-based approach. This model considers four media: air, water, sediment, and ice. The output of the model is the concentration of oil (surrogate hydrocarbons-naphthalene) in these four media, which constitutes the potential exposure to receptors. The concentration profiles can subsequently be used to estimate ecological risk thereby providing guidance to policies for Arctic shipping operations, ship design, and ecological response measures.
Показать больше [+] Меньше [-]Levels of chemicals in two fish species from four Italian fishing areas Полный текст
2016
Guerranti, Cristiana | Grazioli, Eleonora | Focardi, S. (Silvano) | Renzi, Monia | Perra, Guido
This paper reports the results of an assessment of contamination by polychlorinated biphenyls and polycyclic aromatic hydrocarbons in two demersal species of commercial importance. The organisms considered were Mullus barbatus and Engraulis encrasicolus from three marine areas off the Italian coasts: North and South Adriatic Sea and North Tyrrhenian Sea. The instrumental analyzes have revealed, in many samples examined, the presence of most of PCB congeners and 5 of the 16 PAHs considered. Organisms caught in the waters of Apulia have greater contamination values, while the samples from Tuscany showed the lowest ones, results probably referable to the environmental quality differences between the areas of origin, at least for PAHs, since the sampling areas are represented respectively by areas with presence of oil extraction plant (Adriatic), and by an area subject to environmental protection.
Показать больше [+] Меньше [-]Is existing legislation fit-for-purpose to achieve Good Environmental Status in European seas? Полный текст
2016
Boyes, Suzanne J. | Elliott, Michael | Murillas-Maza, Arantza | Papadopoulou, Nadia | Uyarra, Maria C.
Recent additions to marine environmental legislation are usually designed to fill gaps in protection and management, build on existing practices or correct deficiencies in previous instruments. Article 13 of the European Marine Strategy Framework Directive (MSFD) requires Member States to develop a Programme of Measures (PoM) by 2015, to meet the objective of Good Environmental Status (GES) for their waters by 2020. This review explores key maritime-related policies with the aim to identify the opportunities and threats that they pose for the achievement of GES. It specifically examines how Member States have relied on and will integrate existing legislation and policies to implement their PoM and the potential opportunities and difficulties associated with this. Using case studies of three Member States, other external impediments to achieving GES are discussed including uses and users of the marine environment who are not governed by the MSFD, and gives recommendations for overcoming barriers.
Показать больше [+] Меньше [-]Fate, behaviour and weathering of priority HNS in the marine environment: An online tool Полный текст
2016
Cunha, Isabel | Silva, Helena Oliveira da | Neuparth, Teresa | Torres, Tiago | Santos, Miguel Machado
Literature data and data obtained with modelling tools were compiled to derive the physicochemical behaviour of 24 priority Hazardous and Noxious Substances (HNS), as a proxy to improve environmental, public health and political issues in relation to HNS spills. Parameters that rule the HNS behaviour in water and those that determine their distribution and persistence in the environment, such as fugacity, physicochemical degradation, biodegradation, bioaccumulation/biotransformation and aquatic toxicity, were selected. Data systematized and produced in the frame of the Arcopol Platform project was made available through a public database (http://www.ciimar.up.pt/hns/substances.php). This tool is expected to assist stakeholders involved in HNS spills preparedness and response, policy makers and legislators, as well as to contribute to a current picture of the scientific knowledge on the fate, behaviour, weathering and toxicity of priority HNS, being essential to support future improvements in maritime safety and coastal pollution response before, during and after spill incidents.
Показать больше [+] Меньше [-]Analysis of the TSP, PM10 concentrations and water-soluble ionic species in airborne samples over Sistan, Iran during the summer dusty period Полный текст
2016
Dahmardeh Behrooz, Reza | Esmaili-Sari, Abbas | Bahramifar, Nader | Kaskaoutis, D.G.
The present study analyzes the total suspended particulates (TSP) and particulate matter less than 10 μm (PM10) concentrations along with the water-soluble ionic species (WSIS) in airborne dust samples collected in Zabol, located in the Sistan basin of southeast Iran. Rather extreme TSP and PM10 mean concentrations of 1867.0 μg m−3 and 433.4 μg m−3 are found, while the WSIS contribute only 8.9% and 19.3% to the TSP and PM10 mass, respectively indicating large fraction of water-insoluble crustal elements, carbonaceous aerosols and heavy metals that remained unexplored. Ca2+ is the most abundant ionic species contributing ∼25–26% to the total WSIS mass, followed by NH4+, K+, and SO42−. Important fractions of Cl− and Na+ (7–9% of the total WSIS mass) indicate the presence of saline dust storms over Sistan due to desiccation of the Hamoun lakes and uplift of evaporated minerals by the strong Levar (120-days) wind. High correlations between the WSIS suggest large possibility for formation of NaCl, (NH4)2SO4, MgSO4, K2SO4, CaSO4 and NH4NO3. The dusty days (visibility < 2 km) are associated with intense winds (11.7 ms−1 on average) and large increase (∼80–100%) in the concentrations of the crustal elements (e.g., Ca2+, Mg2+ and Cl−) compared to the normal days, while the TSP and PM10 concentrations reach to 4496 μgm−3 and 1010.6 μgm−3, respectively.
Показать больше [+] Меньше [-]Trilateral association between SO2/NO2 emission, inequality in energy intensity, and economic growth: A case of Indian cities Полный текст
2016
Sinha, Avik
Interaction between environmental degradation and economic growth is a growing matter of interest among policymakers. This paper examines the trilateral association between SO2 and NO2 emission, inequality in energy intensity, and economic growth by using simultaneous-equation panel data models for a panel of 139 Indian cities over the period 2001–2013. Our results indicate that there is evidence of feedback hypothesis between NO2 and SO2 emissions and economic growth, economic growth and inequality in energy intensity, and NO2 and SO2 emissions and inequality in energy intensity. The results also verified the existence of Environmental Kuznets curve for both of the pollutants. These results are of interest to environmental and economic policymakers as these can help in coming up with economic policies to ensure environmental sustainability and an inclusive economic growth.
Показать больше [+] Меньше [-]Effect of temporal and spatial variability on the classification of the Ecological Quality Status using the CARLIT Index Полный текст
2016
Cavallo, Marianna | Torras, Xavier | Mascaró, Oriol | Ballesteros, Enric
Methodologies developed by European Member States to assess the environmental quality of their coastal waters under the EU Water Framework Directive (WFD, 2000/60/EC) may have an associated source of uncertainty. Here we identify and quantify the level of uncertainty in the CARLIT (Cartography of littoral and upper-sublittoral communities) methodology to test its effectiveness and reliability. The outcomes show that the effect of temporal variability (among years) within each water body is low when CARLIT is performed every year along the entire rocky coast. The spatial variability within a water body is also low. According to these results, CARLIT could be performed every 3years across all the water body or, alternatively, every year considering at least 60% of each water body, without a significant reduction of the confidence in the classification of the Ecological Quality Status (EQS).
Показать больше [+] Меньше [-]Uncertainties in Atmospheric Mercury Modeling for Policy Evaluation Полный текст
2016
Kwon, Sae Yun | Selin, Noelle E.
Mercury (Hg) contamination is an issue of a growing environmental and public health concern. Atmospheric chemistry transport models for Hg are a critical tool for understanding the sources, processes, and fate of Hg. Uncertainties in multiple aspects of atmospheric Hg models, however, limit their application for policy evaluation and for monitoring global trends in atmospheric Hg concentrations. This review aims to identify uncertainties in atmospheric Hg modeling that are relevant in the context of policy and for informing decision-making. We focus on specific requirements of the Minamata Convention on Mercury, a global treaty signed in 2013 to protect human health and the environment from Hg, to demonstrate how existing uncertainties in atmospheric Hg modeling can influence our ability to evaluate source-receptor relationships. Modeling studies of source attribution suggest that major uncertainties in atmospheric Hg modeling arise from anthropogenic emissions, biogeochemical cycling, and atmospheric chemistry. Uncertainties in these aspects of modeling are expected to increase under the Convention, with regulation of anthropogenic emissions, changes in atmospheric conditions, and legacy and natural Hg source contribution to the global biogeochemical cycle. These uncertainties can interact with one another and with the current Hg species measurement capability and pose challenges to effectively monitoring trends in atmospheric Hg. Developing additional means to attribute simulated atmospheric Hg trends and improve source-receptor relationships in atmospheric Hg models would improve our ability to evaluate the Convention’s effectiveness.
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