Bioassay zur Bestimmung von TCDD-Toxizitätsäquivalenten (TEQ) von Umweltproben und Reststoffen

Polychlorinated aromatic hydrocarbons (HAH) like 2,3,7,8-tetrachloro-p-dioxin (TCDD) elicit a multitude of toxic and biological effects. A common trait of these substances is their affinity for a cytosolic receptor protein and the subsequent induction of the synthesis of several gene products, including cytochrome P450 1A1 (CYP 1A1). In this publication we present a bioassay to determine the induction of CYP 1A1 as a sum parameter for the total toxic potential of critical halogenated compounds in complex environmental matrices. In order to eliminate compounds like polycyclic aromatic hydrocarbons (PAH) and naturally occurring substances which might interfere with the bioassay we developed a simple cleanup procedure. TEQ values derived from bioassay are in good agreement with those obtained from chemical analysis. This bioassay in combination with the simplified “single column” clean up represents a cost and time effective alternative to chemical analysis for the screening of large numbers of environmental matrices.     

Ansätze zur regionalen Quantifizierung von Methan aus Pflanzen

Background

Methane as a gas influencing our climate is of high importance according to the Kyoto-Protocol. The more precisely we can determine anthropogenic and biogenic sources, the more effective measures we can take to reduce the gas. Direct emission of methane from plants apparently contributes significantly to the total emission but has not been accounted for in emission balances until now.

Methods

A model was created to calculate methane emission for a short time period in regional resolution for Lower Austria and to relate the results to known literature.

Results and Discussion

First model results suggest that the amount of methane released from plants in relation to emissions from other known sources are of importance.

Perspectives

The uncertainties associated with both measurements and quantification require reduction by further research.     

Mikrobiologisch-ökotoxikologische Bodenuntersuchungen von zwei zur Unkrautbekämpfung mit hohen Dosierungen eingesetzten Fettsäure-Herbiziden

Goal and Scope

Products based on fatty acids (including acetic acid) are known in plant protection since more than 100 years to control several harmful organisms. In the following decades, however, they lost their importance due to the rapid development of ‘modern’ chemical pesticides. In the meantime some trials were run to control weeds with relatively high doses. The knowledge on its ecotoxic effects on soil microorganisms as a part of the soil fertility, however, is still incomplete.

Methods

Under laboratory conditions two agricultural soils were treated with different dosages of two products based on acetic acid and pelargonic acid (=nonanoic acid) as well as with a biocidal reference compound (e.g. dinitrophenol herbicide). The applied dosages were related to the concentrations in soil reached after simulated penetration of practical field amounts into upper soil layers. In some cases green manuring was simulated by adding lucerne meal to the soil. During the incubation for several weeks biomass-related microbial activities (dehydrogenase activity, substrate-induced shortterm respiration) as well as the mineralization of carbon and nitrogen (including nitrification) were measured.

Results and Conclusion

As compared to ‘normal’ pesticides (e.g. the reference compound) the effects of both test substances on soil microorganisms showed different behaviour. Nearly none of the effects typical for strongly biocidal compounds, namely a dose-related inhibition of microbial biomass combined with a stimulated mineralization (especially of nitrogen), occurred with the fatty acid products. Depending on the marked input of organic carbon by the higher dosages of fatty acid products and their rapid decomposition, especially of acetic acid, an increase of biomass-related parameters and of carbon mineralization combined with a reduction of the available nitrate content (e.g biological nitrogen immobilization) occurred for several weeks. By combining the results of the soil with that of lucerne meal-amended soil ‘real effects’ can be distinguished from those depending on the decomposition of the introduced carbon. In comparison with the strongly biocidal reference compound the two fatty acid products not only caused little microbiological-ecotoxicological impacts on the soil, but often stimulated important microbiological parameters for some time.

Recommendation and Perspective

As result of the trials we recommend an extended microbiological-ecotoxicological test spectrum especially for those plant protection products (pesticides) which should be applied at high dosages or if they contain higher amounts of well decomposable organic substances. This is necessary to distinguish dose-related enhanced biocidal activities induced by biocidal effects (including the subsequent mineralization of the killed microorganisms) from ‘real’ stimulations directly produced by the substrate.     

Auswahl repräsentativer Standorte zur Modellierung der Ausbreitung von gentechnisch veränderten Pflanzen in Nord-Deutschland

Goal and Scope

The use of genetically modified plants (GMP) in agriculture is increasing rapidly. While GMP in North and South America are already established an extensive cultivation in Germany is yet to come. Risk assessment on possible effects of released GMP are mainly based on empirical studies with a small spatial extent (laboratories, small-scale field trials). The joint research project ‘Generic detection and extrapolation of genetically modified rape (GenEERA)’ aimed at estimating the dispersal and persistence of genetically modified oilseed rape (Brassica napus) by the use of individual based models. The objective of the article at hand is to give a detailed account of the spatial variability of climate in Northern Germany (German Federal States of Brandenburg, Lower Saxony and Bremen Mecklenburg Western Pomerania, Schleswig-Holstein and Hamburg). Based on this, a method was developed that includes both, the determination of representative oilseed rapefields for modelling the dispersal of GM oilseed rape at field scale, and the subsequent generalisation of the results to landscapes.

Data and Methods

The statistically founded selection of modelling sites was performed by a compilation of available indicators within a GIS environment which are supposed to be important for the dispersal and the persistence of oilseed rape. Meteorological data on precipitation (P), air temperature (T), and sunshine duration (S) collected at up to 1,200 monitoring sites from 1961–1990 were as well as data on wind conditions (W) aggregated multivariate-statistically by Ward cluster analysis. An ecoregionalisation was used for characterising Northern Germany ecologically. Phenological data on the start of the oil seed rape bloom differentiated in the monitoring periods 1961–1990 and 1991–1999, respectively, were regionalised by performing variogram analysis and kriging interpolation. These maps were used to select appropriate Landsat images to identify rape fields by remote sensing algorithms as well as to define the respective flowering periods for individual based modelling.

Results

The separately generated P-T-S-W-Cluster were aggregated to four homogenic climatic regions. In combination with agricultural clusters defining typical landuse patterns (crop rotation, cultivation management) eight model regions were derived which describe the climatic and agronomic variations in Northern Germany. For each of these regions a representative monitoring site was selected serving for individual based modelling. At last, the modelling results were extrapolated back to the model regions applying corresponding GIS queries.

Discussion

The generated climatic regions reflect the transition of marine climate at the North Sea to continental climate in Northeast Germany. The shift in flowering of oil seed rape coincides with other studies on phenological changes of agricultural crops and wild plants.

Conclusions

Due to the huge calculation efforts and the lack of adequate land registers it was not possible to simulate the potential dispersal of GM oil seed rape at farm scale. Thus, generalisations were used to describe the variations of relevant ecological drivers affecting the dispersal of GMP. It could be shown that the aggregation of those factors to homogenic climatic regions was a successful approximation.

Recommendations and Perspectives

Due to the limited empirical data base it is necessary to validate and substantiate the modelling results by a GMP monitoring. The EU Directive 2001/18/EC on the deliberate release of genetically modified organisms into the environment stipulates assessment of direct and indirect effects of GMP on humans and the environment by case-specific monitoring and general surveillance. It should be realised as soon as possible, since the release and the cultivation of GMP in Germany have been started, already. The monitoring should be complemented by the implementation of a web-based geoinformation system (WebGIS) which enables access to relevant geodata and monitoring data and assists in analysing possible GMP impacts.     

Analyse „stetigkeitsbasierter“ Methoden zur Bestimmung von Stofffrachten in Fließgewässern

Aim and background

Increasing ecological awareness puts the load as a tool for water quality assessment in the foreground. Therefore it is very desirable to find optimal procedures for any given situation on basis of existing data. Criteria will be derived to fill that desire.

Method

The load for a water ingredient is an integrated entity of time-continuous loads (product of concentration and flow) for a given time, i.?e. a year (yearly load). Normally you can only observe a sample (in a statistical meaning) of these data. Therefore, load calculations vary with the concrete sample given. Each such calculation represents an estimation of the load, afflicted with some uncertainty. This uncertainty can be quantified, at least approximatively, by adding variance (scatter around “expected” mean) and the square of bias (divergence of “expected” mean from true mean). This quantity is called “mean squared error”. The methodological results will be illustrated by examples.

Focus

The main focus lies on the methodologies, which, besides data of concentrations observed discretely in time, additionally use quasi-continuously recorded data of other variates, namely the flow. For that situation, statistical models are developed and the load derived and estimated according to existing data. Hereby it is seen that all model based estimation formulae can be described as standard sampling formulae plus some additional terms which stem from comparison of some measurements (i.?e. mean) for quasi-continuous and discrete samples. This way a “continuity-correction” is performed on the standard formulae for the sampling case. This method is called “continuity-based” load determination.

Results

A surprising result is that no complicated mathematical-statistical models are necessary to determine the load. A simple linear concentration- or load-flow-model is sufficient. Additional variates lead, most of the time, to a larger mean squared error in load estimation, even when it is well known that they cannot detoriate the model fit. Only models which describe the concentration extraordinarily precise, near perfection, result in a smaller error.

Implications

It is enough to use one of the given formulae with some “continuity correction” to calculate a load. That can be done without using any software.     

Toxizitätsänderungen in Photoreaktionen von Azaarenen

The azaarenes and the structurally analogous PAH accompany each other and occur ubiquitously in nature. Photochemical conversions like direct photolysis or the photoreaction with nitrate are important natural degradation reactions of azaarenes. Furthermore, photoreactions with chlorine and bromine radicals can be expected in nature. The reactions generate a large number of oxidized, nitrated and halogenated products with unknown toxicity. In this paper, a first screening of changes is reported in acute toxicity during the course of the photochemical reactions. As test system luminescent bacteria are used. For quinoline, isoquinoline and phthalazine the investigations show different changes of the toxicity of the reaction mixtures in dependence on the respective reaction type. The toxicity of the reaction mixtures of quinazoline and quinoxaline increases in all reactions investigated. Furthermore the reactions of bromine radicals with azaarenes also show an increase of the toxicity in all cases. Compared with the azaarenes in all reactions products with significantly higher toxicity are formed.     

Identifizierung toxischer Verbindungen in Sedimenten: Ansätze zur Integration von Wirkung und Bioverfügbarkeit

Sediments play an important role for aquatic ecosystem functions. However, they also act as sink, storage and source of lipophilic toxicants and metals. Effect-directed analysis (EDA) is a powerful tool to identify compounds causing adverse effects. In order to avoid misinterpretations and biased prioritization bioavailability needs to be considered together with effects. Bioavailability is a complex process finally resulting in the transfer of a so far particle bound molecule to the target location within the organism where it causes an effect. In order to operationalize this concept for EDA it can be divided into several partial processes. These include desorption from sediments and thus bioaccessibility, equilibrium partitioning of desorbable compounds between sediment, water and organisms driven by activity, and toxicological bioavailability as a result of toxicokinetics including resorption, transport, metabolization and excretion. Bioaccessibility is based on desorption kinetics and can be simulated with mild extraction methods e.?g. using TENAX. Equilibrium partitioning can be simulated with partition-based dosing techniques. First results with these approaches indicate that consideration of bioavailability increases the significance of polar sediment-associated toxicants relative to classical non-polar contaminants such as polycyclic aromatic hydrocarbons.     

Schnelle vor-ort-analytik zur untersuchung von rüstungsaltlasten

Field screening methods for the analysis of explosives (for which commercial test kits are generally available) are reviewed. These techniques include immunoassays, photometric methods, bio and chemical sensors as well as thin layer chromatography. Basic aspects of these techniques are discussed, their validation is presented and their application to water and soil samples from hazardous ammunition waste is described. An evaluation of field studies with commercial test kits demonstrates that these techniques can be applied successfully for both the exploration of suspected contaminated sites and their sanitation. These methods are used on-site. In general, they allow short analysis times and a high sample throughput, thus leading to a significant reduction of the number of samples to be analysed in the laboratory and the costs.     

GIS-basierte Modellierung von Gewässerimmissionen

Goal and Scope

Environmental assessment of aquatic micro pollutants should consider the spatial and temporal variability of emission, transport and transformation. Simulation models coupled with Geographic Information Systems (GIS) provide digital maps of concentration patterns caused by the overlay of multipoint and diffuse emissions and natural attenuation processes in river basins. The paper gives an overview on GIS-based models for river basins and demonstrates the applicability by using some illustrating examples with GREAT-ER.

Main Features

Georeferenced models have several advantages: visualization of concentration patterns, investigation of spatial and temporal concentration profiles, analysis of exceedance of environmental quality standards, embedding in integrated river basin management systems.

Results and Discussion

GIS-based models allow a more realistic assessment. Monitoring programmes should be designed to deliver appropriate measured data for the evaluation and improvement of models.

Recommendation and Perspectives

The combination of digital maps, simulation models and environmental monitoring would provide better approaches for the risk assessment and water quality management of aquatic micro pollutants.     

Detektoren zur Kartierung des Redox-chemischen Gewässermilieus

For the time being, simple and reliable methods which permit the imaging of the complex topography of contaminant plumes in groundwater are missing. The conventional methods for the punctual determination of contaminant concentrations cannot fulfill this demand. To successfully implement and utilize. Natural Attenuation, these deficits have to be overwhelmed. The detectors described in the following represent only part of the probing device system the authors have developed; it shall enable their user to image different aspects of plume topography and its time dependent change by monitoring within the undisturbed groundwater aquifer in groundwater measuring levels:

? relative freights of contaminants and trace contaminants by passive samplers [4] and

? redox milieu parameters by detectors.

The detectors offer multi-purpose, tape-like probing devices of unlimited length. They are charged with a defined reserve of reactive substances. During monitoring actions, the derector tape hangs vertically stretched by a weight preferably covering from the top to the bottom of the whole water column. During the reaction period, the detector may be relaunched for repeated visual inspection. The colour changes of the detectors enable the identification of a row of parameters in the vertically (depth-) oriented profile by unbroken optical/visually perceivable imaging:

? Position of Redox potential thresholds for Mn-IV-Mn-II, Fe-III-Fe-II, Sulfate-Sulfide

? Position of ochre precipitation and iron-sulfide precipitation horizons

? Relative freights of the sum of substances effecting reduction (period until defined oxidant reserve has been reduced)

? Relative freights of the sum of substances effecting iron-sulfide oxidation (period until defined reductant reserve has been reduced)

? Position of dissolved iron-II ions containing horizons

? Position of dissolved hydrogen-sulfide ions/hydrogen-sulfide containing horizons

? Relative freights of iron-II ions (period until defined oxidant reserve has been reduced)

? Relative freights of hydrogen-sulfide ions/hydrogen-sulfide (period until defined oxidant reserve has been reduced). Furthermore, the detectors are also suitable for the examination of waters even of great depth, as for example artificial or natural lakes, sea and ocean basins.

     

Bewertungsmaßstäbe zur Beurteilung von Schadstoffbelastungen in Böden anhand der Bioverfügbarkeit

Until now, assessment of contaminated sites is based on variable protection goals, whereby total contents and in part mobile contents are considered. Due to interactions of pollutants in soil and bound residues, total contents do not reflect the actual risk. In contrast an investigation based on availability/bioavailability of contaminants would enable a harmonization of the protection-goal-based evaluation and a closer-to-reality risk assessment for the individual location.     

Teil II: Verfahren zur Monetarisierung von Ökosystemleistungen

As it is practically impossible in an industrial society to reduce impacts into ecosystems to a level that would preclude any damages, the need for damage valuation arises. One of the available valuation tools is the economic approach. Subsequent publications present this approach using the example of soils. In this second part, two methods are presented for monetarising ecosystem services, the contingent valuation method, the valuation on the basis of restoration and replacement costs. Common arguments against the monetarisation of ecosystems, like the omission of intrinsic values or the incomplete information of individuals, are then discussed. In conclusion, limits and possibilities of monetarising ecosystem services are described.     

Stabilitätsverhalten von ausgewählten anorganischen Spurenstoffen in Niederschlagsproben

The stability of H⁺, NH ₄ ⁺ , and PO ₄ ^3? ions in rainwater samples was in vestigated under different conditions cf storage and transport. Microbiological and physicochemical processes account for changes. Suppression of microbiological activities in deposition networks using conventional analyses may be achieved by adding AgCl-powder and by cooling to +4 °C.     

Entwicklung und Einsatz eines standardisierten Labortests für Dungkäfer (Aphodius constans) zur Prüfung der Ökotoxizität von Veterinärpharmaka

Goal, Scope, and Background

According to European legislation, an environmental risk assessment of veterinary pharmaceuticals for dung beetles is required if the substance is a parasiticide for the treatment of pasture animals. However, the demonstration of the environmental safety of those substances for dung beetles is strongly hampered by the fact that no standardized test system is available so far. Therefore, starting with recommendations from the SETAC advisory group DOTTS (Dung Organism Toxicity Test Standardization), a test system using the widespread temperate dung beetle species Aphodius constans was developed.

Methods

Using experiences gained at the University of Montpellier (e.g. in field studies) and in other terrestrial tests, details of culturing and testing of A. constans were investigated in a project sponsored by the German Environment Protection Agency (UBA). Basically, the survival of young larvae of A. constans exposed to the test substance spiked into formulated (i.e. dried, grounded and re-wetted) or fresh dung is measured over a period of three weeks. Using the model substance dimethoate (an insecticide required as positive control in tests with the predatory mite Hypoaspis aculeifer) the suitability of the new test was checked. Afterwards, the new test method was used to determine the toxicity of four common veterinary pharmaceuticals (ivermectin, dicyclanil, moxidectin, praziquantel) in formulated and fresh dung. Finally, the effects of ivermectin on the dung beetles were determined in a test using fresh dung from treated cattle.

Results and Conclusions

For Dmethoate LC₅₀-values were found in a range of 1–3 mg a.s./kg dung (dew.), depending on the dung type. Praziquantel did not show eirecis in the tested concentration range (i.e. up to 1000 mg a.s./kg Dung (DW). The LC₅₀-values of the other three pharmaceuticals were very low (<6 mg a.s./kg dung (DW)). With the exception of Dicyclanil no differences between formulated and fresh dung were identified. In the case of ivermectin the LC₅₀-value were even lower: about 0.5 mg a.s./kg dung (DW). No differences between the results of test in which the substance was spiked into dung and those tests which were performed with dung from treated cattle were found. These results prove the sensitivity as well as the robustness of this test method.

Recommendations and Perspectives

Based on the experiences reported here, it is recommended to standardize this test in an international ring test so that it can be incorporated in the risk assessment process for veterinary pharmaceuticals as described in the currently developed international registration guidelines.     

Ökotoxikologische Wirkungen von Teeröl-imprägnierten Holzpfählen

Aim and Scope

This study was aimed at evaluating environmental effects of tar-oil impregnated (tanalized) tree stakes using simple and efficient biotests to obtain results of its ecological impacts during the tar-oil breakdown in the stake.

Results

1. Soil respiration was measured in-situ as an indication of soil microbial activity in two field trials. Soil respiration was measured in a 20 year-old apple orchard at various distances from the tar-oil impregnated tree stakes and also on soil mixed with chippings from pine stakes with tar-oil impregnation of different ages.
2. Cress germination tests were employed to evaluate tar-oil phytotoxicity in a field and laboratory trial. Cress was seeded close to tree stakes in the same 20 year-old apple orchard and germination rates related to tar oil-impregnation. Cress was also seeded in trays in sand mixed with pine chippings from stakes with tar-oil impregnation of different ages.
3. The portion of the carcinogenic benzoapyrene (BaP) ranged between 0.0015% in freshly tar-oil impregnated to 0.4% in tar-oil impregnated 20-year old trees stakes, i.e. irrespective of the overall PAK concentration and its degradation.
4. Kinetic analysis using DIXON plots showed a 50% breakdown of overall PAHs after ca. 2.7 years, i.e. km or Ki values of less than 3 years.

Conclusion

Germination tests of cress and endogenous seeds as well as soil respiration proved sensible indicators of the phytotoxicity and ecotoxicity of tar-oil impregnated tree stakes in fruit orchards. Soil respiration proved particularly sensitive to tar-oil ageing. Its combination with kinetic inhibition models resulted in parameters suitable for the interpretation of results.     

Photometrische Bestimmung der Zytotoxizität von Chemikalien

Two test methods are presented to assess the cytotoxicity of chemicals. On one hand the protozoonTetrahymena pyriformis and on the other the bacteriumPseudomonas aeruginosa is cultured in defined media containing the test chemicals. Test parameter is the quantity of living cells surviving exposure. The conversion of the tetrazolium salt MTT into formazan is equivalent to cell viability. A mixture of detergent and isopropanol is used to dissolve the blue formazan which is not soluble in water, prior to photometric measurement. For cetyltrimethylammonium bromide, benzyldimethyldodecylammonium chloride, dodecylbenzenesulfonic acid sodium salt, potassium dichromate, 4-toluenesulfonic acid sodium salt, and 4-nitrophenol the EC50-values (mol/l) in theTetrahymena pyriformis- (Pseudomonas aeruginosa) test system were: 10^?5,81 (10^?5,08); 10^?4,68) (10^?3,80; 10^?4,50 (10^?4,14); 10^?3,97 (10^?5,11); 10^?2,71 (10^?2,50) and 10^?4,00 (10^?3,64). — With the assays described here it is possible to measure a large number of samples by quick and simple means.