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91.
M. C. Chukwuma E. T. Eshett E. U. Onweremadu Ph.D. M. A. Okon 《International Journal of Environmental Science and Technology》2010,7(2):261-270
The study investigated zinc availability in relation to selected soil properties in a crude-oil-polluted Eutric Tropofluvent in Egbema, Southeastern Nigeria. For this purpose, three treatments have been applied: unpolluted soil, polluted without vegetation and polluted with vegetation with five replicates arranged in a randomized complete block design. Guided by transect sampling technique, soil sampling was carried out in June 2008. Soil samples were collected from the three different land units using soil auger at a depth of 0–20 cm. Standard laboratory procedures were adopted in analysing the soils. Soil generated data were subjected to analysis of variance and correlation analysis. Results showed highly significant variation (p = 0.01) in bulk density, porosity, silt: clay ratio, pH, effective cation exchange capacity, percent base saturation, total nitrogen, organic matter, available phosphorus, calcium: magnesium ratio and zinc. It was found that zinc was higher in crude oil polluted soils than in non-polluted soil and it was below critical limits. Zinc availability in relation to selected soil properties in the crude oil polluted soils indicated that clay and organic matter did not affect zinc availability, while pH and effective cation exchange capacity did. A study on zinc dynamics in crude-oil-polluted soils will certainly provide further information on the management of crude-oil-polluted soils since it is one of the key micronutrient for crop productivity. 相似文献
92.
93.
A. U. Zaman 《International Journal of Environmental Science and Technology》2013,10(5):1029-1038
Waste-to-energy technologies are considered as one of the key waste treatment technologies due to their energy and heat recovery efficiencies from the waste. A number of research studies were accomplished to understand the potential environmental burdens from emerging waste treatment technologies such as pyrolysis–gasification (PG). The aim of this study was to examine the PG of municipal solid waste (MSW) treatment process through a life cycle assessment (LCA) method. The study also includes a comparative LCA model of PG and incineration to identify the potential environmental burdens from the existing (incineration) and emerging (PG) waste treatment technologies. This study focused on ten environmental impact categories under two different scenarios, namely: (a) LCA model of PG and (b) comparative LCA model of PG and incineration. The scenario (a) showed that PG had significant environmental burdens in the aquatic eco-toxicity and the global warming potential impact categories. The comparative scenario (b) of PG and incineration of MSW showed that PG had comparatively lower potential environmental burdens in acidification, eutrophication, and aquatic eco-toxicity. Both LCA models showed that the environmental burdens were mainly caused by the volume of the thermal gas (emissions) produced from these two technologies and the final residue to disposal. Therefore, the results indicate that the efficiency and environmental burdens of the emerging technologies are dependent on the emissions and the production of final residue to the landfill. 相似文献
94.
K.?MinouraEmail author F.?Imamura U.?Kuran T.?Nakamura G. A.?Papadopoulos D.?Sugawara T.?Takahashi A. C.?Yalciner 《Natural Hazards》2005,36(3):297-306
A tsunamigenic sediment layer has been discovered in fluvio-alluvial sequences on the northern coast of the Marmara Sea, northwestern
Turkey. The layer consists of unsorted silty coarse sand including terrestrial molluscs and charcoal fragments. The AMS radiometric
ages of the shells have been estimated at around BC 400, AD 300, AD 400, and AD 1000. We propose that a tsunami occurred in
the Marmara Sea in the middle of 11th century and invaded the fluvial plains. The older fossils were derived from the underlying
horizons, and it is probable that buoyant materials such as terrestrial molluscs and charcoals were isolated from liquefied
sediments during submarine sliding. Slope failure of coastal blocks triggered by fault movement generated tsunamis, which
might have transported floating materials to the backshore. 相似文献
95.
An Eocene magmatic belt across central Tibet: mantle subduction triggered by the Indian collision? 总被引:2,自引:0,他引:2
F. Roger P. Tapponnier N. Arnaud U. Schärer M. Brunel X. Zhiqin & Y. Jingsui 《地学学报》2000,12(3):102-108
Mountain domes rising to ≈ 6600 m along Tibet's Tanggula range herald the Eocene intrusion of calcalkaline granites into terranes accreted much earlier. Together with coeval, cogenetic volcanics, such intrusives, which have similar crystallization and cooling ages, may be part of an ESE-trending belt cutting central Tibet in half. This magmatic belt may have marked a former northern boundary of the plateau, testifying to S-directed subduction of the Asian mantle. Such subduction would have developed soon after India's collision but long before the rise of the plateau's present rims, along one of central Tibet's Mesozoic sutures. 相似文献
96.
The analysis of various factors influencing mineral availability documents future short-and long-term mineral-commodity supply trends. The lifetime of reserves, the development of the relative importance of production centres and the forecasting of the depletion of a resource base are mainly geological factors, although the category “reserves”, in contrast to “resources”, is determined by technical and economical aspects. These three factors govern the short-and long-term supply of mineral commodities. The intensity-of-use factors and the growth rate of consumption are variables related to the demand of mineral commodities. They influence the decision of companies for certain commodities as targets for exploration and investment in production centres. Both factors control the short-to medium-term mineral supply. Finally, the lead time to production is a technical variable, although influenced by ore deposit type, and controls short-term mineral availability. 相似文献
97.
A series of elevated imbricated boulders were investigated on the Otago coastline, southeast New Zealand, through field surveying and optical luminescence dating. By using established hydrodynamic relationships of sediment transport the energy required to move the clasts was calculated and compared to the historic record of marine inundations of that coast. The boulders are platy in shape and are over 2 m long in some cases, and are sourced from a locally outcropping conglomerate unit which appears to be the only lithology on this section of coast that erodes to produce clasts of this size. It is estimated that the boulders were deposited by a tsunami between 2 and 3 m high during the latter part of Marine Isotope Stage 5. They therefore represent the first pre-Holocene tsunami deposit and one composed of large boulders described on the New Zealand coastline. 相似文献
98.
Hydrogeological processes in seasonally frozen northern latitudes: understanding, gaps and challenges 总被引:1,自引:1,他引:1
A. M. Ireson G. van der Kamp G. Ferguson U. Nachshon H. S. Wheater 《Hydrogeology Journal》2013,21(1):53-66
The groundwater regime in seasonally frozen regions of the world exhibits distinct behavior. This paper presents an overview of flow and associated heat and solute transport processes in the subsurface, from the soil/vadose zone, through groundwater recharge to groundwater discharge processes in these areas. Theoretical developments, field studies and model development are considered. An illustrative conceptual model of the system is presented. From a groundwater perspective, the dominant effect is the extent of hydraulic isolation between the water above and that below the near-surface frozen zone. The spatial and temporal occurrences of this isolation are seasonally variable and may also be modified under a future changing climate. A good qualitative conceptual understanding of the system has been developed over numerous decades of study. A major gap is the inability to effectively monitor processes in the field, particularly unfrozen water content during freezing conditions. Modeling of field-scale behavior represents a major challenge, even while physically based models continue to improve. It is suggested that progress can be made by combining well-designed field experiments with modeling studies. A major motivation for improving quantification of these processes derives from the need to better predict the impacts of a future changing climate. 相似文献
99.
The John’s creek valley (Johnsbachtal) is presented as a long-term, interdisciplinary cooperation platform in upper Styria (Austrian Alps) that brings together the interests and knowledge of persons with different backgrounds (scientists, teachers, students, as well as local actors and the population) with the central aim to generate mutual benefit for all involved parties. It covers an area of around 65 km2 with elevations between 600 and 700 m in the valley to over 2,300 m in the summit regions. Annual mean temperature ranges from approximately 8 °C in the lower elevations of the valley to below 0 °C in the summit regions. Annual precipitation mounts to values of 1,500 mm and more than 1,800 mm in the lower elevations and summit regions, respectively. To allow for a long-term monitoring of the complex meteorological and hydrological conditions in the area, a hydroclimatological monitoring network has been installed that is described in detail in this paper. A special characteristic of the installed meteorological stations is that they cover a large range of altitudes and, therefore, allow to capture the gradients in meteorological variables induced by the complex Alpine topography. Furthermore, the hydroclimatological monitoring network in John’s creek valley is largely independent of regular third-party project funding, and therefore, not temporarily limited in its existence. A number of catchment research activities that cover a variety of disciplines (e.g., climatology, hydrology, (hydro)geology, geomorphology) and that largely benefit from the hydroclimatological data recorded in John’s creek valley are presented together with preliminary results. The latter include spatial distributions of meteorological and hydrological variables (e.g., precipitation, evapotranspiration and snowmelt) calculated for the test site using the hydrometeorological model AMUNDSEN. Furthermore, the results of hydrogeological investigations that have been carried out at the Etzbach spring are presented and discussed. 相似文献
100.
Sarah U. Wisseman Duane M. Moore Randall E. Hughes Mary R. Hynes Thomas E. Emerson 《Geoarchaeology》2002,17(7):689-715
Provenance studies of stone artifacts often rely heavily upon chemical techniques such as neutron activation analysis. However, stone specimens with very similar chemical composition can have different mineralogies (distinctive crystalline structures as well as variations within the same mineral) that are not revealed by multielemental techniques. Because mineralogical techniques are often cheap and usually nondestructive, beginning with mineralogy allows the researcher to gain valuable information and then to be selective about how many samples are submitted for expensive and somewhat destructive chemical analysis, thus conserving both valuable samples and funds. Our University of Illinois team of archaeologists and geologists employs Portable Infrared Mineral Analyzer (PIMA) spectroscopy, X‐ray diffraction (XRD), and Sequential acid dissolution/XRD/Inductively coupled plasma (SAD‐XRD‐ICP) analyses. Two case studies of Hopewellian pipes and Mississippian figurines illustrate this mineralogical approach. The results for both studies identify sources relatively close to the sites where the artifacts were recovered: Sterling, Illinois (rather than Ohio) for the (Hopewell) pipes and Missouri (rather than Arkansas or Oklahoma) for the Cahokia figurines. © 2002 Wiley Periodicals, Inc. 相似文献