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.     

Integrierte Treibhausgasbewertung der Prozessketten von Erdgas und industriellem Biomethan in Deutschland

Background The use of natural gas has increased in the last years. In the future, its import supply and transport structure will diversify (longer distances, higher share of LNG (liquefied natural gas), new pipelines). Thus the process chain and GHG emissions of the production, processing, transport and distribution might change. Simultaneously, the injection of bio methane into the natural gas grid is becoming more important. Although its combustion is regarded as climate neutral, during the production processes of bio methane GHG emissions are caused. The GHG emissions occurring during the process chain of energy fuels are relevant for the discussion on climate policy and decision making processes. They are becoming even more important, considering the new Fuel Quality Directive of the EU (Dec. 2008), which aims at controlling emissions of the fuel process chains. Aim In the context of the aspects outlined above the aim is to determine the future development of gas supply for Germany and the resulting changes in GHG emissions of the whole process chain of natural gas and bio methane. With the help of two gas consumption scenarios and an LCA of bio methane, the amount of future emissions and emission paths until 2030 can be assessed and used to guide decision processes in energy policy. Results and discussion The process chain of bio methane and its future technical development are outlined and the related emissions calculated. The analysis is based on an accompanying research study on the injection of bio methane to the German gas grid. Two types of biogas plants have been considered whereof the “optimised technology” is assumed to dominate the future market. This is the one which widely exploits the potential of process optimisation of the current “state of the art” plant. The specific GHG emissions of the process chain can thus be nearly halved from currently 27.8?t CO₂-eq./TJ to 14.8?t CO₂-eq./TJ in 2030. GHG emissions of the natural gas process chain have been analysed in detail in a previous article. Significant modifications and a decrease of specific emissions is possible, depending on the level of investment in the modernisation of the gas infrastructure and the process improvements. These mitigation options might neutralise the emission increase resulting from longer distances and energy intensive processes. In the last section two scenarios (low and high consumption) illustrate the possible development of the German gas supply until 2030, given an overall share of 8–12?% of bio methane. Considering the dynamic emission factors calculated in the former sections, the overall gas emissions and average specific emissions of German gas supply can be given. The current emissions of 215.4 million t CO₂-eq. are reduced by 25?% in the low-consumption scenario (162 million t CO₂-eq.), where consumption is reduced by 17?%. Assuming a consumption which is increased by 17?% in 2030, emissions are around 7?% higher (230.9 million t CO₂-eq.) than today. Conclusions Gaseous fuels will still play a significant role for the German energy supply in the next two decades. The GHG emissions mainly depend on the amount of gas used. Thus, energy efficiency will be a key issue in the climate and energy related policy discussion. A higher share of bio methane and high investments in mitigation and best available technologies can significantly reduce the emissions of the process chain. The combustion of bio methane is climate neutral compared to 56?t CO₂/TJ caused by the direct combustion of natural gas (or 111?t CO₂/TJ emitted by lignite). The advantage of gaseous energy carriers with the lowest levels of GHG emissions compared to other fossil fuels still remains. This holds true for fossil natural gas alone as well as for the expected future blend with bio-methane.     

Bestimmung des Ferntransports von persistenten organischen Spurenstoffen und der Umweltexposition mittels Modelluntersuchungen

Background, Aim and Scope

Many environmental pollutants are slowly degrading (persistent) and very mobile. They are semivolatile, i.e. they are partitioned between the environmental media of soil, water and air, and undergo long-range transport. The combined action of climate and substance properties determines the distributions and fate of these substances, among them as the persistent organic pollutants (POPs), other pesticides and industrial chemicals.

Main Features

Multicompartment chemistry-transport models are under development in order to study environmental exposure models.

Results

The investigation of transport and fate of some POPs on the global scale has emphasized the significance of historically explicit and geo-referenced simulations for substance distributions, persistence and long-range transport potential. Apart from the substance properties, it is the regional climate which is most important. This was illustrated by studies into the regional cycling of DDT and γ-HCH in selected tropical and extra-tropical regions.

Discussion

The isolation of individual steps of subsequent cycles of emission, transport and deposition (a so-called grasshopper effect) in model experiments shows the potential to elucidate the complex superposition of substance properties and environmental conditions, variable in time and space.

Conclusions

The results suggest that the grasshopper effect enhances the long-range transport potential, but is not required to explain an accumulation in polar regions (at least for γ-HCH).

Perspectives

A number of relevant scientific questions should be addressed by exposure modelling.     

Zur quantitativen Verteilung von Bakterien und Hefen in einem Gezeitenstrand der Nordseeküste

On a sandy beach of the island Sylt (North Sea) bacteria and yeasts are distributed according to a characteristic pattern. In regard to the vertical distribution, the highest bacteria numbers are found on the surface area of the sediment (14 million per 1 cc of fresh sediment); there is a continuous decrease with depth. The lowest bacteria numbers are those from the underground water region (20,000 per 1 cc). The highest number of yeasts is 200 per 1 cc of sand. The horizontal distribution has 2 maxima, 1 in the sandy mud flats and 1 in the supralittoral zone, with a bacteria abundance minimum inbetween on the beach slope. Actinomycetes have been identified only in the middle and upper part of the beach slope. In May and August (1967) the average number of bacteria was nearly twice as high as in October, December and March. No definite relation was noted between the abundance of bacteria and yeasts on the one hand, and organic substance and oxygen availability, on the other.     

Über Bau und Funktion der Kiemen und Lungen von Ocypode ceratophthalma (Decapoda: Crustacea)

Electron micrographs reveal great differences between the epithelial linings of gills and lungs in the air-breathing crab Ocypode ceratophthalma. According to the fine structure, the gills have a mainly osmoregulatory function; they exhibit a very active transporting epithelium characterized by a large number of mitochondria, branched microvilli, and basal labyrinth. Blood spaces in the shaft of the gills are lined by podocytes, suggesting ultrafiltration. The lungs are typical respiratory organs, lined by a thin epithelium covered by a thin cuticle.     

Mathematische Analyse der kombinierten Wirkung von Temperatur und Salzgehalt auf den Stoffwechsel von Tilapia mossambica (Teleostei)

Job (1969 a, b) has presented experimental results on the influence of temperature and salinity on the rate of oxygen consumption in Tilapia mossambica. He evaluated his results on the basis of the allometric function. The present paper analyses, in addition, the data obtained on the basis of the temperature function proposed by the present author. The parameters of this formula reveal that, in 50 and 100% sea water, the curves for the logarithmic values for the given body weights are parallel to each other; only the slope is different for the two salinities. In fresh water, the logarithmic temperature curves diverge. Job's results clearly demonstrate that it is not possible to explain the differences in the respiratory metabolism of this fish on the grounds of the energy expenditure for osmoregulation. The present author supposes that the differences found in the rate of respiration are caused by differences in the ionic composition of the internal milieu in the different salinities.     

Charakterisierung von Cyaniden in Böden und industriellen Abfällen mit der Fourier-Transformations-Infrarot-Spektrometrie

Soils on sites of former coking and manufactured gas plants as well as on those of blast furnaces are frequently contaminated with cyanides (CN). For assessing the possible risk arising from these hazardous compounds, it is necessary to analyze a considerable number of samples quickly as well as at low costs. Fourier transform infrared (FTIR) spectroscopy has the advantage of being much easier in handling compared to conventional wet-chemical methods for analyzing cyanides. For testing FTIR spectroscopy in the application mentioned above, pure cyanide compounds as well as contaminated purifier waste, blast furnace sludge, and spiked soils were investigated by the reflexion and the transmission techniques. Applicability of the attenuated total reflexion (ATR) technique was limited, since the absorption bands of the crystal used (diamond) overlapped in the range of the cyanide-specific absorption. Although the environmental samples investigated have unfavorable optical properties, results obtained by the transmission technique (KBr pressed pellets) were much better than those obtained by the reflexion technique. Pure cyanide compounds could be distinguished by their IR spectra because their absorption bands of the cyanide-valence vibration differed in position, shape and intensity. The soil matrix did not interfere with either the intensity or the shape and position of the absorption maxima, as concluded from the IR spectra of spiked soil samples. Applying the transmission technique, cyanides are detected at concentrations larger than 500 mg kg^?1 CN. However, the signal was low when the cyanide concentration was below 1,000 mg kg^?1 CN. The FTIR spectroscopy is capable of detecting cyanide compounds in soils and industrial wastes. Additionally, the method provides information about the cyanide species, which is important in toxicological assessments. FIIR spectroscopy is a suitable method for a first survey and environmental assessment of cyanide contaminated areas.     

Anwendungen von Pflanzenschutzmitteln in der Landwirtschaft

A political dispute has broken out over a research project by the Federal Environmental Agency (UBA) concerning the use of plant protection agents in agriculture. Under Article 15 para. 1 No. 3 d and e of the Plant Protection Act, plant protection agents can only be authorised if their proper and appropriate use, or the consequences of such use, have no negative impacts on human or animal health or on other biological communities, especially water bodies. In specific cases the Federal Environmental Agency as the approving authority fulfils the legislative requirements with a conditional authorisation. Thus, for example, specified minimum distances to the water body must be observed according to the toxicity and exposure of the plant protection agent. The many continuing negative impacts on water bodies from the use of plant protection agents raise questions as to whether certain plant protection agents ought not to have been authorised, and whether environmental requirements were strict enough in the past or whether farmers did not comply with them to a sufficient degree. The research project described here will clarify and document possible improper practices and practical problems. Investigations will be undertaken without prior notice, as only this will enable the actual practices to be recorded. Data will be anonymous, since the project does ’not aim to ‘convict’ individual farmers. The task of the project is to collect representative data for the whole of Germany. Initial interim results will be available in 2006. This report will then be continued in a ‘Part 2’.     

Einfluß von Benetzungsspannung und lonen auf die Substratbesiedlung und das Einsetzen der Metamorphose bei Bryozoenlarven (Bowerbankia gracilis)

Settlement and metamorphosis in larvae of Bowerbankia gracilis depend on the wettability of the substratum. The wettability of a solid can be characterized by it's specific contact angle, . Larvae settle on solids with angles >17°, but not on surfaces with high wettability properties. In an attempt to explain this phenomenon, we consider the larvae as a second liquid and their attachment as a second wetting. In such case, water and larvae would compete in wetting the substratum. Adhesion can be accounted for by assuming the wetting tension of solid to water to be lower than that of the larval surface (|_solid/water| < |_solid/larvae|). Adhesion would thus be favoured energetically. The rate of settlement and that of metamorphosis are demonstrated as depending on the degree of contact angle, , in an all-or-none fashion. Settlement of larvae on high-wetting solids is prevented by high capillary pressure accruing at the point of contact. Metamorphosis is initiated by contractions occurring after adhesion. Application of CsCl or KCl induces such contractions and metamorphosis in free-swimming larvae. MgCl₂ prevents the onset of metamorphosis but not adhesion. Two mechanisms are considered as possibly accounting for induction of metamorphosis: (1) mechanical stimulation by shearing the cilia at the point of contact, and (2) a chemical stimulation of the cell membrane after application of K⁺ or Cs⁺.     

Toxizität und anreicherung von blei bei der miesmuschel Mytilus edulis im laborexperiment

In a laboratory experiment, conducted over 130 days, three batches of a total of 100 common mussels, Mytilus edulis, were maintained in media containing different lead concentrations. Two vessels served as controls. There was no acute injury to the mussels; but, over an extended period of time, a marked increase in mortality occurred which was related to the lead concentration in the medium. The median lethal time (LT₅₀) was computed to be 218 days for the control, 150 days with 0.5 mg Pb/l in the medium, 129 days with 1 mg/l, and 105 days with 5 mg/l. Quantitative analyses of the soft parts of M. edulis by flameless atomic-absorption-spectrophotometry revealed a distinct accumulation of lead. From a natural lead content of 8.4 μg Pb/g dry weight, the lead concentration increased to 12,840 μg/g at 0.5 mg/l, to 20,770 μg/g at 1 mg/l and to 39,830 μg/g at 5 mg/l. The ratio of the concentration of lead in the soft parts of M. edulis to the concentration in the medium remained in the same order of magnitude both under laboratory conditions using high lead concentrations and under in situ lead levels. Over a period of 130 days, lead uptake expressed as percentage of lead offered was 10.9% at 0.5 mg/l, 9.5% at 1 mg/l, and 3.4% at 5 mg/l, respectively.     

Die Rolle von Kommunikation in der Umweltbewertung

Goal and Scope

Planning projects concerning the environment often provoke problems due to a lack of transparency of the applied scales and the appropriate evaluation methods. This paper therefore examines the general structure of all valuation processes before describing the character of the economic evaluation method in detail. From this point of view, requirements on planning processes are coming out which are to be achieved if their duty — the provision of public goods — is to be carried out efficiently.

Features

It will be shown that from an economist’s perspective a planning procedure acts as a surrogate of the market in coordinating individual’s preferences. The reasons for the inefficient level of the provision of environmental goods by private producers are their main characteristics: non-rivality and non-excludability; therefore public goods do not possess prices. Thus environmental goods have to be produced by cooperation and planning processes have to guarantee this. The main character of planning procedures is be seen in communication processes which is documented by a narrative study.

Results and Conclusions

Planning projects concerning the environment are strongly contingent on communication processes. Thus, they are also controllable by communication. The interdisciplinary research in communications shows that cooperative behaviour which is required for planning projects that should provide public goods can be benefited by applicative communication technologies. In this juncture (social) norms more and more emerge to act an important part in conveying cooperative behaviour. Especially so called ‘Sozialtechniken’ seem to be able to activate such norms.

Outlook

From the economist’s point of view planning projects concerning the environment mostly desiderate two things: Firstly, the procedures and methods which are applied to evaluate the regarding environmental goods in many cases suffer from transparency. Secondly, individual’s preferences predominant by the local population and accordingly by the directly involved parties are mostly not acquired adequately to achieve an efficient allocation of environmental goods. Applying more communication technologies to solve these two problems in the future both an increase of efficiency and an increase of the acceptability of such planning projects can be expected.