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11.
The spatially and temporally varying environmental quality of a metropolitan area is described by means of empirically derived environmental indices. The approach is based on the principles of benefit analysis and consists of a number of logical steps including the selection, the measurement and determination of the spatial distribution, and the normalization (scaling) of the selected environmental indicators. To derive composite indices, the normalized indicators are weighted, based on the Delphi technique and subsequently aggregated. The results are given by means of isopleths, including single and composite index isopleths plotted by computer on common maps.World Health Organization  相似文献   
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苔藓Lophozia ventricosa挥发油化学成分研究   总被引:1,自引:0,他引:1  
采用水蒸气蒸馏法提取苔藓Lophozia ventricosa挥发油,用毛细管色谱法对挥发油进行了分析,采用归-化法确定各组分的相对含量,并用GC—MS联用技术对分离的化学成分进行鉴定.经计算机检索并结合文献调研,共鉴定出28个化合物,占挥发油总量的93.3%,其中含1个单萜、23个倍半萜(15个为含氧倍半萜)和1个二萜,主要成分为Maalioxide(45.6%)和Eudesma-4.(15),7(11)-dien-8-one(28.9%).图2表1参12  相似文献   
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The biochemical response of wild sticklebacks collected in Autumn 2005 at seven stations in the North of France was studied using a set of complementary biomarkers. Here, data on biotransformation of xenobiotics, oxidative stress exposure and damages, neurotoxicity and endocrine disruption are provided. All the sites are characterized by a specific response pattern that allows distinguishing sampling locations. Moreover, these responses are in accordance with data on existing environmental pressures and the chemical analysis of metals performed in surface water. The assessment of individual responses is completed by fish population disturbance monitoring. Based on these measurements, the investigated sites are characterized by different levels of disturbance. This study argues for a multi-parametric approach of aquatic ecosystem contamination based on association between chemical, biochemical and ecological endpoints and provides a testimony of the usefulness of stickleback for this purpose.  相似文献   
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The aim of this study was to characterize biomarker responses in three-spined sticklebacks exposed to prochloraz (Pcz). For this purpose, adult sticklebacks were exposed for 2 weeks to prochloraz at 0, 10, 50, 100 and 500 microg/L prior to one week of depuration in clean water. At days 7, 14 and 21, several hepatic biomarkers were measured including 7-ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT), total glutathione (GSH) content and thiobarbituric acid reactive substances (TBARS). Pcz induced a transient increase of antioxidant enzymes and a depletion of glutathione content during the first 7 days of exposure. This study showed that EROD activity and antioxidants were disrupted in a transient manner. GST was rapidly induced in a dose-dependent manner and this induction was persistent and observed also after depuration. GST appeared as a valuable biomarker to assess the exposure to Pcz.  相似文献   
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6   ha, or 6% of the country's total area. The environmental implications of this large-scale conversion have so far received little attention; the present study examined some of these implications. A review of research on soil physical and chemical aspects of the conversion of permanent grassland into arable land reveals that such a large-scale conversion may have considerable effects upon the environment. For example, due to the mineralization of soil organic matter a release of NO3 and CO2 into the environment can be expected on the order of 10 t N and 100 t C per hectare. Environmentally equally severe, if not worse, is the increased amount of surface runoff that can be expected from converted grassland soils in arable land during winter because of surface sealing and soil compaction. This increased surface runoff, in combination with the runoff from other farmland, may be one of the reasons for the growing frequency of floods along major German rivers in recent years. In view of the lasting adverse environmental effects of permanent grassland conversion and the subsidized agricultural surpluses in Germany today, we conclude that a reconversion of arable land into permanent grassland may be beneficial both environmentally and economically.  相似文献   
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BACKGROUND, AIM AND SCOPE: Problems of long-term existence of the environmental contaminant 2,4,6-trinitrotoluene (TNT) and necessities for the use of trees ('dendroremediation') in sustainable phytoremediation strategies for TNT are described in the first part of this paper. Aims of the second part are estimation of [14C]-TNT uptake, localisation of TNT-derived radioactivity in mature tree tissues, and the determination of the degree of TNT-degradation during dendroremediation processes. METHODS: Four-year-old trees of hybrid willow (Salix spec., clone EW-20) and of Norway spruce (Picea abies) were cultivated in sand or ammunition plant soil (AP-soil) in wick supplied growth vessels. Trees were exposed to a single pulse application with water solved [U-14C]-TNT reaching a calculated initial concentration of 5.2 mg TNT per kg dry soil. Two months after application overall radioactivity and extractability of 14C were determined in sand/soil, roots, stem-wood, stem-bark, branches, leaves, needles, and Picea May sprouts. Root extracts were analysed by radio TLC. RESULTS: 60 days after [14C]-TNT application, recovered 14C is accumulated in roots (70% for sand variants, 34% for AP-soil variant). 15-28% of 14C remained in sand and 61% in AP-soil. 3.3 to 14.4% of 14C were located in aboveground tree portions. Above-ground distribution of 14C differed considerably between the angiosperm Salix and the gymnosperm Picea. In Salix, nearly half of above-ground-14C was detected in bark-free wood, whereas in Picea older needles contained most of the above-ground-14C (54-69%). TNT was readily transformed in tree tissue. Approximately 80% of 14C was non-extractably bound in roots, stems, wood, and leaves or needles. Only quantitatively less important stem-bark of Salix and Picea and May shoots of Picea showed higher extraction yields (up to 56%). DISCUSSION: Pulse application of [14C]-TNT provided evidence for the first time that after TNT-exposure, in tree root extracts, no TNT and none of the known metabolites, mono-amino-dinitrotoluenes (ADNT), diaminonitrotoluenes (DANT), trinitrobenzene (TNB) and no dinitrotoluenes (DNTs) were present. Extractable portions of 14C were small and contained at least three unknown metabolites (or groups) for Salix. In Picea, four extractable metabolites (or groups) were detected, where only one metabolite (or group) seemed to be identical for Salix and Picea. All unknown extractables were of a very polar nature. CONCLUSIONS: Results of complete TNT-transformation in trees explain some of our previous findings with 'cold analytics', where no TNT and no ADNT-metabolites could be found in tissues of TNT-exposed Salix and Populus clones. It is concluded that 'cold' tissue analysis of tree organs is not suited for quantitative success control of phytoremediation in situ. RECOMMENDATIONS AND OUTLOOK: Both short rotation Salicaceae trees and conifer forests possess a dendroremediation potential for TNT polluted soils. The degradation capacity and the large biomass of adult forest trees with their woody compartments of roots and stems may be utilized for detoxification of soil xenobiotics.  相似文献   
19.

Goal and Background

Since consequences of global climate change include even contradicting directions and trends in different regions and seasons, regional studies are a necessity to understand regional problems and risks. Extreme precipitation is a highly variable climate element in time and space with serious economic and ecological impacts. The analysis of changes in the Saxonian precipitation characteristics is one constituent in our understanding of global climate change and regional climate-related risk assessment.

Methods

Changes of regional precipitation patterns and their extremes were analysed based upon data from 21 stations in Saxony from 1934 to 2000. Eighteen stations delivered 50-year data sets (1951–2000) and three stations (Altmörbitz, Chemnitz, Neuhausen) delivered daily precipitation data over 67 years (1934–2000). Differentiated by season and half-year periods, trends were calculated for the relevant parameters by linear regression. The trend significance was determined by the non-parametric Mann-Kendall-trend test.

Results and Conclusion

In the summer half of the year, distinctively more dry conditions developed. Over the same period, the winter half of the year became more wet. Regarding trends of extreme precipitation, a strong dependency to the size of the choosen treshold value exists. During the summer, size and excess frequency of the 90th and 95th percentiles have increased, whereas they decreased in the winter. On the other hand, the half year trends of the 99th percentile are predominantly positive. Particularly the trend towards more dry conditions in summer is of substantial relevance for the economy and water management.

Recommendations and Perspective

The additional analysis of further precipitation data sets, provided by the Saxonion Climate database, will advance the regional accuracy of the presented findings. In addition work on the adjustment of an extreme distribution to daily and monthly precipitation sums is needed, and an effect-related definition of dry periods needs to be developed.  相似文献   
20.
For the estimation of intestinal absorption of polychlorianted dibenzodioxins/dibenzofurans (PCDD/F), ain-vitro model was developed in order to study PCDD/F mobilization by digestion of technogenic soils using ?Kieselrot” (red slag) as substrate and digestive juice model mixtures. Red slag samples were shaken successively with model mixtures of saliva, gastric juice, duodenal juice and bile. The solids were separated, the aqueous phase was extracted with hexane, the hexane extract analyzed for PCDD/F. Additionally, the PCDD/F-content of the red slag was determined. Extraction efficiency was tested with three different digestive juice model mixtures and also tap water for comparision. The percentage of PCDD/F transferred from the red slag sample into the digestive juice mixture was defined as absorption availability. In our experiments, a maximum absorption availability of 2 % was found.  相似文献   
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