Wirkungsschwellen für chemische Stoffe in Biosystemen Eine theoretische Betrachtung

Die aus der chemischen Umsetzung mit endogenen Molekülen resultierende biologische Wirkung von Fremdstoffen wird diskutiert, ausgehend von den Grunds?tzen der Thermodynamik und Kinetik. Dabei führt ein unter vereinfachenden Annahmen durchgeführter Vergleich der thermischen Energieverteilung von Molekülen mit typischen biochemischen Aktivierungsenergien zu dem Ergebnis, da? aus statistischen Gründen für jede mit stofflichen Umsetzungen zusammenh?ngende biologische Wirkung ein Schwellenwert existieren sollte.     

Veränderung von Biokonzentration und Wirkung vom PSM in Anwesenheit von Huminstoffen

Humic substances, in aqueous bodies primarily fulvic acids, may demonstrate an inhibitory as well as an activating influence on organisms. We present evidence with bacteria-containing algal cultures and with cultures of the nematodeCaenorhabditis elegans. Structural elements of the fulvic acids which may be responsible for such effects are not yet known. Furthermore, the presence of fulvic acids may lead to increases in bioconcentration of xenobiotics. Increase in the toxicity of xenobiotics in the presence of humic substances have also been described. We present studies applying lethal as well as sublethal toxicity endpoints.     

全球化学品管理战略:机遇和风险

由以往和化学品安全相关的国际活动发展而来的国际化学品管理战略(SAICM)得到了联合国环境署(UNEP)理事会的支持.全球化学品行业认为SAICM应该被作为实现世界可持续发展首脑会议议定目标的路线图.全球在化学品安全使用问题上的不断进步将要求生产者、销售者、使用者、政府和其他利益相关方在生产链各有关环节责任分担的基础上采取共同协调的行动.从这个意义上说,制定一个全球战略提供了通过建立新的伙伴关系来实现化学品安全的机会.但是,如果SAICM成为国家、地区和国际层面附加的更严格的调控手段的基础,则其可能达不到期望的影响.     

Flow and diffusion measurements in natural porous media using magnetic resonance imaging

Flow and diffusion of water in natural porous media, quartz sand, and calcareous gravel were measured using a 1.5-T clinical magnetic resonance tomograph. The spatial resolution of the dynamic measurements was 1.32 x 1.32 x 5 mm3, and the time between two cross-sectional measurements was approximately 10 s. The measured coefficients of molecular diffusion for water were in good agreement with theoretical data. Flow was measured without any tracer at velocities between 0.15 and 6.67 mm/s. The results, based on a calibration within one part of the column, were in good agreement with data obtained from a tracer experiment and from a numerical model. It was possible to measure the flow velocity in larger pores and preferential flow paths directly. The results of the flow measurements in smaller pores reflected the mean velocity within that volume element. In that case the obtained values were close to the average linear velocity. Since the time resolution is high a monitoring of flow processes is possible. The pore space was imaged with a spatial resolution of 0.5 x 0.5 x 0.5 mm3. Here, the porosity of pores that are larger than 0.2 mm can be measured directly; for smaller pores a calibration is necessary.     

Linking socio-economic factors, environment and land cover in the German Highlands, 1945-1999

Land-cover changes are caused by human activities and natural ecological processes. Thus, our study uses an interdisciplinary approach to research land-cover changes. We present a method to (i) link socio-economic/environmental factors and land-cover changes, (ii) identify indicators of land-cover changes, and (iii) distinguish between socio-economic and environmental indicators associated with local types of overall land-cover changes. The study was conducted in the Lahn-Dill Highlands, Germany, a typical marginal rural landscape. In this region, we investigated land-cover changes occurring over the period 1945-1999. Land-cover data were derived from multi-temporal aerial photographs. Types of overall land-cover changes characterising the districts within the study area were differentiated. With the help of redundancy analysis (RDA), we analysed the relationships between land-cover changes and widely available socio-economic/environmental factors. The results reveal that both individual land-cover changes at patch level and types of overall land-cover changes characterising districts are correlated with socio-economic and environmental factors. Whereas the stable environmental factors are drivers of land-cover changes in our rural study area, socio-economic factors introduced into the analysis mostly result from land-cover changes. We identified correlative socio-economic indicators that cannot explain land-cover changes, but that in combination with the environmental factors can be used to greatly facilitate the reconstruction of past land-cover changes and thus lead to a better knowledge of land-cover history. Based on the types of overall land-cover changes, the results of the study can be adopted for the study of land-cover changes in other regions.     

Individual preparedness and mitigation actions for a predicted earthquake in Istanbul

This study investigated the process of taking action to mitigate damage and prepare for an earthquake at the individual level. Its specific aim was to identify the factors that promote or inhibit individuals in this process. The study was conducted in Istanbul, Turkey—where an earthquake is expected soon—in May and June 2006 using qualitative methods. Within our conceptual framework, three different patterns emerged among the study subjects. Outcome expectancy, helplessness, a low socioeconomic level, a culture of negligence, a lack of trust, onset time/poor predictability, and normalisation bias inhibit individuals in this process, while location, direct personal experience, a higher education level, and social interaction promote them. Drawing on these findings, the paper details key points for better disaster communication, including whom to mobilise to reach target populations, such as individuals with direct earthquake experience and women.