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991.
David W. Ostendorf Baoshan Xing Niki Kallergis 《Journal of contaminant hydrology》2009,106(3-4):118-130
At a former wood preservation plant severely contaminated with coal tar oil, in situ bulk attenuation and biodegradation rate constants for several monoaromatic (BTEX) and polyaromatic hydrocarbons (PAH) were determined using (1) classical first order decay models, (2) Michaelis–Menten degradation kinetics (MM), and (3) stable carbon isotopes, for o-xylene and naphthalene. The first order bulk attenuation rate constant for o-xylene was calculated to be 0.0025 d− 1 and a novel stable isotope-based first order model, which also accounted for the respective redox conditions, resulted in a slightly smaller biodegradation rate constant of 0.0019 d− 1. Based on MM-kinetics, the o-xylene concentration decreased with a maximum rate of kmax = 0.1 µg/L/d. The bulk attenuation rate constant of naphthalene retrieved from the classical first order decay model was 0.0038 d− 1. The stable isotope-based biodegradation rate constant of 0.0027 d− 1 was smaller in the reduced zone, while residual naphthalene in the oxic part of the plume further downgradient was degraded at a higher rate of 0.0038 d− 1. With MM-kinetics a maximum degradation rate of kmax = 12 µg/L/d was determined. Although best fits were obtained by MM-kinetics, we consider the carbon stable isotope-based approach more appropriate as it is specific for biodegradation (not overall attenuation) and at the same time accounts for the dominant electron-accepting process. For o-xylene a field based isotope enrichment factor εfield of − 1.4 could be determined using the Rayleigh model, which closely matched values from laboratory studies of o-xylene degradation under sulfate-reducing conditions. 相似文献
992.
Urbanization and its impact on groundwater: a remote sensing and GIS-based assessment approach 总被引:1,自引:0,他引:1
The perils of unplanned urbanization and increasing pressure of human activities on hydro-geomorphologic system often result
in modification of the existing recharge mechanism, which leads to many environmental consequences. In the present research,
an attempt has been made to investigate the applicability of remote sensing and geographical information system (GIS) in dealing
with spatial and temporal variability of dynamic phenomena, like urbanization and its impact on groundwater. This paper covers
primarily, quantitative and qualitative impacts of urban growth on the behavior of aquifer in Ajmer city (India). Urban growth
of the Ajmer city in last 17 years has been estimated from the satellite images. Database related to urbanization and groundwater
has been created in GIS. Groundwater recharge has been computed using a water balance approach known as Water Level Fluctuation
Methodology. Recharge estimation methodology has been implemented in GIS to introduce the spatial variability of hydro-geological
characteristics. Further, temporal and spatial variations in groundwater quality and quantity have been correlated with urban
growth using overlay analysis in GIS. The study reveals a general decline in water table and quality with urbanization. Further,
remote sensing and GIS technologies have been found useful in assessment of spatial and temporal phenomena of urbanization
and its impact on groundwater system. 相似文献
993.
Epidemiological studies suggesting the possibility of harmful effects on human (specifically children’s leukaemia) due to
long-term exposure to magnetic fields of extremely low frequency (e.g. 50/60 Hz) and relatively low values (i.e. over the
microtesla range) have stirred high activity in the topic of magnetic field mitigation. To reduce these fields, it is common
to use passive metal screens (e.g. plates made of aluminium or steel). To design them, effective and fast numerical computations
are highly desirable. In this article, a method is presented, which computes various parameters of screens in a given shielding
problem and yields magnetic field distribution and shielding factors. The method takes into consideration the 3D field distribution
and is able to solve systems with large aspect ratios (thin thickness in comparison with its other dimensions); this is a
common problem where other methods such as finite elements often experience difficulties. The presented method computes separately
the field inside and outside the screens. Afterwards, the solutions are “stitched” together along the border of the subregions.
Two practical examples are given of the developed numerical method. 相似文献
994.
Thomas G. Measham 《Environmental management》2009,43(6):1096-1107
Conventional approaches to evaluation of environmental programs have tended to limit themselves to restricted measures of
program effectiveness. This paper shows how a social learning approach can be incorporated into evaluating public environmental
programs. A social learning approach is particularly suited to complex environmental challenges which are inherently difficult
to understand, predict, and manage, thus complicating the evaluation process. The paper presents an Australian case study
of dryland salinity management where there are major knowledge barriers impeding conventional management techniques. The research
presented in this paper focused on evaluating a public demonstration program to track its impact through its design, implementation,
and monitoring phases. The paper shows that, by incorporating social learning principles and practices, program evaluation
can promote collective action, critical reflection, and increased knowledge to underpin improved environmental management. 相似文献
995.
George R. Offen David Eskinazi Michael W. McElroy John S. Maulbetsch 《Journal of the Air & Waste Management Association (1995)》2013,63(7):864-871
From March 23rd to 26th, 1987, the city of New Orleans hosted 350 attendees, including representatives from 15 foreign countries, at the 1987 Joint Symposium on Stationary Combustion NOx Control. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA), the symposium provided attendees the opportunity to hear 49 papers in nine sessions covering technological and regulatory developments on NOx control in the United States and abroad since the May 1985 symposium in Boston. Session topics included general environmental issues, low-NOx combustion equipment (i.e., low-NOx burners, reburning, etc.), flue gas treatment, fundamental combustion research, and special issues for cyclone coal-fueled boilers, oil- and gas-fired boilers, and industrial combustion applications. Advances to the state-of-the-art presented at this symposium include: improved and/or newly applied combustion modifications for pulverized coal-fired boilers; further analyses of reburning, the leading combustion modification option for cyclone-equipped boilers; initial experiences with catalytic flue gas treatment in Europe; studies of NOx control retrofit options for oil- and gas-fired utility systems; and new technology developments for coal, oil, and gas fueled utility and industrial combustors. This paper summarizes those presentations that discussed significant changes since May 1985 in areas of potential interest to EPRI and its utility members. Where appropriate, they include our perspectives on the applicability of these newly disclosed findings to utility systems. 相似文献
996.
This paper presents an innovative, quantitative assessment of pollution avoidance attributable to environmental regulation enforced through integrated licensing, using Ireland's pharmaceutical-manufacturing sector as a case study. Emissions data reported by pharmaceutical installations were aggregated into a pollution trend using an Environmental Emissions Index (EEI) based on Lifecycle Assessment methodologies. Complete sectoral emissions data from 2001 to 2007 were extrapolated back to 1995, based on available data. Production volume data were used to derive a sectoral production index, and determine ‘no-improvement’ emission trends, whilst questionnaire responses from 20 industry representatives were used to quantify the contribution of integrated licensing to emission avoidance relative to these trends. Between 2001 and 2007, there was a 40% absolute reduction in direct pollution from 27 core installations, and 45% pollution avoidance relative to hypothetical ‘no-improvement’ pollution. It was estimated that environmental regulation avoided 20% of ‘no-improvement’ pollution, in addition to 25% avoidance under business-as-usual. For specific emissions, avoidance ranged from 14% and 30 kt a− 1 for CO2 to 88% and 598 t a− 1 for SOx. Between 1995 and 2007, there was a 59% absolute reduction in direct pollution, and 76% pollution avoidance. Pollution avoidance was dominated by reductions in emissions of VOCs, SOx and NOx to air, and emissions of heavy metals to water. Pollution avoidance of 35% was attributed to integrated licensing, ranging from between 8% and 2.9 t a− 1 for phosphorus emissions to water to 49% and 3143 t a− 1 for SOx emissions to air. Environmental regulation enforced through integrated licensing has been the major driver of substantial pollution avoidance achieved by Ireland's pharmaceutical sector — through emission limit values associated with Best Available Techniques, emissions monitoring and reporting requirements, and performance targets specified in environmental management plans. This compliant sector offers a positive, but not necessarily typical, case study of IPPC effectiveness. 相似文献
997.
Dror Hawlena 《Behavioral ecology and sociobiology》2009,64(2):205-213
Colorful tails that become cryptic during ontogeny are found in diverse taxa. Nevertheless, the evolutionary bases for this
change remain debated. Recent work suggests that colorful tails, deflective displays, and striped patterns may represent antipredator
mechanisms used by immature lizards to compensate for being more active and hence more vulnerable to predation (increased
movement hypothesis, IMH). I challenged the generality of IMH by comparing foraging behavior and frequency of tail displays
across five Acanthodactylus lizards that vary in fundamental life history traits, before and after the tail changed color. As these species underwent
changes in tail coloration, they congruently adopted less risky behaviors and reduced the frequencies of tail displays. Contrary
to expectation, in two species, the hatchling risky behavior resulted not from increased movements but from longer stay in
exposed microhabitats. I suggest that colorful tails and deflective tail displays are synergistic antipredator mechanisms
neonates use to minimize the fitness consequences of using various risky behaviors rather than increased movement alone. 相似文献
998.
Cornelia Meinert Emma Schymanski Eberhard Küster Ralph Kühne Gerrit Schüürmann Werner Brack 《Environmental science and pollution research international》2010,17(4):885-897
Background, aim and scope
The importance of groundwater for human life cannot be overemphasised. Besides fulfilling essential ecological functions, it is a major source of drinking water. However, in the industrial area of Bitterfeld, it is contaminated with a multitude of harmful chemicals, including genotoxicants. Therefore, recently developed methodologies including preparative capillary gas chromatography (pcGC), MOLGEN-MS structure generation and mutagenicity prediction were applied within effect-directed analysis (EDA) to reduce sample complexity and to identify candidate mutagens in the samples. A major focus was put on the added value of these tools compared to conventional EDA combining reversed-phase liquid chromatography (RP-LC) followed by GC/MS analysis and MS library search. 相似文献999.
Chen B Pan Y Wang J Fu Z Zhang Y Zhou Y 《Environmental monitoring and assessment》2012,184(6):3545-3556
Evenly distributed sampling design is generally considered as an efficient sampling design. It is widely used in sampling
for the environmental survey. In this paper, we present a novel method for generating N evenly distributed samples within a given irregular polygon via simulating the movements of some ideal homogeneous point
charges. Initially, charges are randomly put into the sampling region; then, they are freed and held orderly; and after enough
runs, the charges will finally reach a stable state with all of them having a zero resultant force and velocity; and so they
distribute evenly within the region. Their layout can thus be considered as an evenly distributed sampling design. The main
advantages of this method are: (1) it is easy to understand and implement; (2) it is efficient in both running and generating
better designs. Analysis and experimental results indicate that this method is an efficient and robust method for generating
even sampling designs for 2D polygonal sampling region. 相似文献
1000.
Towards institutional analysis of sustainability science: a quantitative examination of the patterns of research collaboration 总被引:2,自引:2,他引:0
This paper examines quantitatively the patterns of collaboration over geographical boundaries in the emerging field of sustainability
science by empirically analyzing the bibliometric data of scientific articles. The results indicate that an increasing number
of countries are engaged in research on sustainability, with the proportion of articles published through international collaboration
rising as well. The number of countries engaged in international collaboration on sustainability research has been increasing,
and the diversity of countries engaged in research collaboration beyond national borders is also increasing. The geographical
patterns of collaboration on sustainability show that research collaboration tends to be conducted between countries which
are geographically located closely, suggesting that communication and information exchange might be limited within the regional
clusters. The focused fields of research activities on sustainability are significantly different between countries, as each
country has its focused fields of research related to sustainability. The specialization of research activities is also observed
in international collaboration. While these patterns of international collaboration within regional clusters focusing on specific
fields could be effective in promoting the creation, transmission, and sharing of knowledge on sustainability utilizing the
already existing regional networks, they could pose a serious obstacle to collecting, exchanging, and integrating diverse
types of knowledge, especially when it is necessary to deal with problems involving large-scale complex interactions with
long-term implications, such as climate change. It would be of critical importance to establish inter-regional linkages by
devising appropriate institutional arrangements for global research collaboration on sustainability science. 相似文献