Gentoxische Substanzen in Wässern

Waste waters with genotoxic potential are produced in various technical processes. Diffuse sources such as traffic and agriculture as well as point sources as mining, power plants, waste and waste water treatment facilities may emit water which shows mutagenic activity in bacteria test systems. A variety of compounds is known as mutagenes but in case studies it was not possible to assign the mutagenic potential of water to specific compounds. The chlorination and ozonation of drinking water may also generate genotoxic and cancerogenic compounds but at present it is not possible to assess the health risk of various drinking water disinfection methods.     

Bestimmung und Bewertung der Emissionen von PCDD/PCDF,PAK und kurzkettigen Aldehyden in den Brandgasen von Kerzen

Exhaust fumes of paraffin, beeswax and stearin candles without any further paint or decorative element were analysed for the toxicological important substance classes of PCDD/PCDF, PAH and short chain aldehydes. The candle waxes and wicks were investigated for chlorinated dioxins, furans and some known precursors. Toxicological risk assessment shows that emissions of the investigated candles are much lower than all administrative limitation values — even under “worst case conditions”. Thus, they do not produce a toxicological risk for human health.     

Abwasserbehandlung beim kontrollierten Rückbau einer Pflanzenschutzmittelfabrik

During the demolition of an industrial building contaminated with chlorophenols and polychlorinated dibenzodioxins (from Boehringer & Sohn in Hamburg-Moorfleet, Germany), several measures must be taken in order to protect the surroundings. Since these compounds are strongly adsorbed by particulate matter, a mist is continuously sprayed over the whole building. The waste water is expected to be highly contaminated and must therefore undergo extensive purification procedures. The primary goal of the existing study is to examine whether or not the present effluent reprocessing unit, a system which is comprised of a charcoal filter, is able to clean the waste water according to legal requirements. Secondly, the main factors that influence the clean up of the effluent were investigated in order to design a suitable precleaning unit for the contaminated water should the present reprocessing unit not fulfill these requirements. By means of the factorial design technique, the effect of three factors (flow velocity of the water, amount of charcoal and the pH-value) on the efficiency of the cleaning process and with regard to chlorophenols was examined. Surprisingly, the pH-value does not have a significant effect on the efficiency. In addition, the results of the experiments show that a precleaning of the effluent is not required.     

Die Lösung von Nutzungskonflikten aufgrund flächenhafter Bodenkontaminationen mit Hilfe Geografischer Informationssysteme und Mitteln der Geostatistik

Goal and Scope

By means of Geographical Information Systems (GIS) and other geostatistical methods, the extensive heterogeneous data materials of large area soil contaminations are re-evaluated to eliminate exploitation conflicts and investment obstacles.

Methods

The mapping of relevant frame criteria generates the basis to solve the conflicts, such as types of exploitation of field areas, development plans, protected areas, flooded areas, etc. as well as their geo-referencing in the Geographical Information System. The critical examination of data age and quality as well as the geostatistical evaluation by means of semivariogram analysis and Kriging technique are essential prerequisites for the determination of areas related to utility and exceeding test values.

Results and Conclusions

As a result, one can modify the hazardous situation and can provide recommendations for an optimal elimination of hazards, mostly in the framework of scheduled measures in terms of town planning.

Outlook

On the basis of the results obtained, further exploitation or monitoring work can clearly be optimized.     

Von der Erkenntnis zur Entscheidung

This contribution highlights the role and importance of ecotoxicology in regulatory decisions of chemicals legislation focussing on the responsibilities of the German Federal Environmental Agency (UBA). Therefore, organisational structures and processes relevant for making decisions concerning the risks of chemicals to men and the environment are described. As any regulatory decision starts with scientific findings, a brief overview of UBA’s activities with regard to own research and to initiate research in the area of ecotoxicology is provided. In addition, the vast importance of standardisation and international harmonisation of guidelines for testing and assessment of chemicals is illustrated, including the time- and ressource consuming character of these harmonisation processes. Subsequently, the involvement of regulatory decision making in intense and controversial scientific and political debates is emphasised. The transparency of these discussions and the independence of science is critically addressed in this context. In a final chapter the job requirements and options for qualification in Germany are described, ending up with a brief summary of the positive experiences with UBA’s contribution to the new advanced training course in ecotoxiciology realised by GDCh/SETAC GLB. A summary of the discussions on these different topics emphasises the specific challenge in regulatory ecotoxicology: To generate knowledge relevant for decision making, while acting in an area of conflict between scientific demands and economical as well as political interests.     

Propagation of olfactory information within the honeybee hive

Transfer of information about food source characteristics within insect societies is essential to colony-foraging success. The food odor communicated within honeybee hives has been shown to be important for food source exploitation. When successful foragers return to the nest and transfer the collected nectar to hive mates through mouth-to-mouth contacts (trophallaxis), potential recruits receiving these samples learn the food odor by associative learning. The food then becomes rapidly distributed among colony members, which is mainly a consequence of the numerous trophallaxes between hive-mates of all ages during food processing. We tested whether the distribution of food among hive mates causes a propagation of olfactory information within the hive. Using the proboscis extension response paradigm, we show that large proportions of bees of the age groups representing the main worker castes, 4 to 9-day-old bees (nurse-aged bees), 12 to 16-day-old bees (food processor-aged bees), and actual foragers (about 17+ day old bees) associatively learn the food odor in the course of processing food that has been collected by only a few foragers. Results further suggest that the information is shared more or less equally between bees of the three age groups. This shows that olfactory information about the flower species exploited by foragers is distributed within the entire colony and is acquired by bees of all age groups, which may influence many behaviors inside and outside the hive.     

RNA interference: from an ancient mechanism to a state of the art therapeutic application?

Now that the sequencing of many genomes has been completed, the basic challenges are finding the genes and predicting their functions. Up until now, a large information gap has existed between the knowledge of genome sequence and our knowledge of protein function. The assessment of gene function may be performed using the tools of reverse genetics, including knock-out mice, antisense oligomers, aptamers, and ribozymes. These approaches have been superseded by RNA interference (RNAi), which exhibits much more potency for the investigation of protein function than the techniques listed above. As already known some years ago, RNAi is based on an ancient anti-viral defense mechanism in lower eukaryotes. It is induced by double-stranded RNA and its processing to 21–23 nt small interfering RNAs (siRNAs), which cause the degradation of homologous endogenous mRNA. The way RNAi works has still to be determined, but it already serves as a first-choice approach to generate loss-of-function phenotypes among a broad variety of eukaryotic species, such as nematodes, flies, plants, fungi and mammals. RNAi also represents an extremely powerful tool, becoming a therapeutic approach to curing infectious diseases originated by viral or parasitic invasion. In this review we present the current view of how RNAi works in different eukaryotic species and its high potential for functional genomics and in rational drug design.     

Synthesis of effects in four Arctic subregions

An assessment of impacts on Arctic terrestrial ecosystems has emphasized geographical variability in responses of species and ecosystems to environmental change. This variability is usually associated with north-south gradients in climate, biodiversity, vegetation zones, and ecosystem structure and function. It is clear, however, that significant east-west variability in environment, ecosystem structure and function, environmental history, and recent climate variability is also important. Some areas have cooled while others have become warmer. Also, east-west differences between geographical barriers of oceans, archipelagos and mountains have contributed significantly in the past to the ability of species and vegetation zones to relocate in response to climate changes, and they have created the isolation necessary for genetic differentiation of populations and biodiversity hot-spots to occur. These barriers will also affect the ability of species to relocate during projected future warming. To include this east-west variability and also to strike a balance between overgeneralization and overspecialization, the ACIA identified four major sub regions based on large-scale differences in weather and climate-shaping factors. Drawing on information, mostly model output that can be related to the four ACIA subregions, it is evident that geographical barriers to species re-location, particularly the distribution of landmasses and separation by seas, will affect the northwards shift in vegetation zones. The geographical constraints--or facilitation--of northward movement of vegetation zones will affect the future storage and release of carbon, and the exchange of energy and water between biosphere and atmosphere. In addition, differences in the ability of vegetation zones to re-locate will affect the biodiversity associated with each zone while the number of species threatened by climate change varies greatly between subregions with a significant hot-spot in Beringia. Overall, the subregional synthesis demonstrates the difficulty of generalizing projections of responses of ecosystem structure and function, species loss, and biospheric feedbacks to the climate system for the whole Arctic region and implies a need for a far greater understanding of the spatial variability in the responses of terrestrial arctic ecosystems to climate change.