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491.
Different methods exist for measuring soil water and solute fluxes in and below the root zone and have been critically reviewed. Besides indirect methods (e.g. water balance, tensiometer, time domain reflectometry – TDR, frequency domain reflectometry – FDR, environmental tracer) direct methods (e.g. drainage-type lysimeter, water fluxmeter) have a long tradition and have been successfully used in seepage research. A large weighable out door lysimeter is the best method for obtaining reliable data about seepage water quantity and quality, but it involves significant investment and additional expenses for maintenance. To tackle this problem new methods for the vertical collection of large volume soil monoliths (up to 6 m3) as well as for the horizontal collection (up to 6 m3) have been developed. For the placement of the lysimeter a container lysimeter unit was constructed, which is cheaper than a conventional steel or concrete cellar. Furthermore, the technical design of the newly developed lysimeter types as a weighable gravitation lysimeter, a weighable groundwater lysimeter and a lateral flow lysimeter are presented.  相似文献   
492.
In Europe more than 2,500 lysimeters operated by research institutes and industry (Lanthaler 2005). Originally lysimeters were built for investigations of soil water and solutes, nutrient leaching and pesticide degradation (see e.g. Winton and Weber 1996). Currently lysimeters additionally used as a tool for investigations on biological processes, and structural changes of plants, including root distribution, and enzyme activities etc. (see e.g. Dizer et al. 2002; Schloter et al. 2005).  相似文献   
493.
The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH ( approximately 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were <2microgl(-1) whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44microgl(-1)). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR.  相似文献   
494.
Fine particles in the atmosphere from soil and sand resuspension contain a variety of organic compounds from natural biogenic and anthropogenic matter. Soil and sand samples from various sites near Kuwait city were collected, sieved to retain the fine particles, and extracted with a mixture of dichloromethane and methanol. The extracts were derivatized and analyzed by gas chromatography-mass spectrometry in order to characterize the chemical compositions and sources of the organic components. The major inputs of organic compounds were from both natural biogenic and anthropogenic sources in these samples. Vegetation was the major natural source of organic compounds and included n-alkanols, n-alkanoic acids, n-alkanes, sterols and triterpenoids. Saccharides had high concentrations (31–43%) in the sand dune and seafront samples, indicating sources from decomposed vegation materials and/or the presence of viable microbiota such as bacteria and fungi. Vehicular emission products, leakage of lubricating oils, discarded plastics and emissions from cooking operations were the major anthropogenic inputs in the samples from the urban areas. This input was mainly UCM, n-alkanes, hopanes, plasticizers and cholesterol, respectively.  相似文献   
495.
Ohne Zusammenfassung DOI:http://dx.doi.org/10.1065/uwsf2000.02.001  相似文献   
496.

Goal and Scope

The information value of microbiologicalecotoxicological investigations of pesticides in soil increases if reference compounds with known biocidal effects are included. But those reference compounds used until now often are of remarkable environmental and human toxicity and therefore are difficult to handle. Inorganic neutral salts sometimes were discussed as alternatives, but their suitability needs to be tested before.

Methods

For laboratory experiments some microbial activities in soil were selected whose effects had been proved in several microbiological-ecotoxicological investigations. They include the mineralization of carbon and nitrogen (+ nitrification) as well as the biomass-related parameters dehydrogenase activity and substrate-induced short-term respiration. Several agricultural soils were used to confirm the results.  相似文献   
497.
498.
An experimental system is described, which opens up a novel pathway towards a molecular understanding of the origin of life. The systemic conditions for the evolution of biological macromolecules are investigated in detail.  相似文献   
499.
In den letzten Jahren werden in vielen Ländern eher die Abfallkomponenten als vielmehr die Stoffmischungen betrachtet. Das gesetzliche Rahmenwerk des Stoffstrommanagement kann dazu beitragen, die Probleme auf wissenschaftlicher Grundlage zu lösen. Der Einfluss der neuen Gesetzgebung in Deutschland und Europa auf das Stoffstrommanagement sowie auf die Entwicklung neuer Techniken bei Abfallentsorgung und-recycling wird in diesem Beitrag untersucht. Neue Prinzipien für das Abfallmanagement werden vom Management der Stoffströme abgeleitet.  相似文献   
500.
The AIDS debate   总被引:1,自引:0,他引:1  
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