Fischpopulationen unter Stress – das Beispiel des Unteren Neckars

Background, aim, and scope Reports about declines or unusual structures of fish populations in native aquatic systems in Central Europe and North America are in sharp contrast to an obvious improvement of general water quality. The Neckar River may serve as an example of a formerly severely contaminated freshwater system in Southern Germany, the ecological situation of which could be substantially improved over the last three decades. Nevertheless, there are still deficits in the composition of the fish fauna, which cannot be explained by conventional chemical-analytical, hydromorphological and limnological methodologies. Therefore, in search of explanations for ecological deficits, ecotoxicological investigations with an increasing focus on sediment contamination have been performed along the Lower Neckar River over a period of 10 years. In addition to sediment tests, fish populations were screened for genotoxic and embryotoxic effects as well as alterations in the structure of central metabolic organs such as the liver. Materials and methods Roach (Rutilus rutilus) and gudgeon (Gobio gobio) from the Lower Neckar River were studied with respect to histo- and cytological alterations of the liver as well as the induction of genotoxicity in liver, gut, gills and blood cells by means of the comet and micronucleus assays. At the same time, both native sediments and acetonic sediment extracts were tested for toxicity to zebrafish (Danio rerio) embryos and permanent fish cell cultures. Results Massive disturbances of the liver ultrastructure indicate severe stress in the fish from the Lower Neckar River despite good supply of nutrition. Both cyto- and embryotoxicity tests document a considerable toxic potential of sediments from the Lower Neckar River, and results of both the comet assay and the micronucleus test provide evidence of the presence of genotoxic agents in the sediments and their effects in fish. There has been no decrease of genotoxicity over the last 10 years. Discussion Cytopathology in conjunction with general cyto- and embryotoxicity in fish from the Lower Neckar River contribute to a syndrome which cannot be neglected in the interpretation of abnormal compositions of fish populations. In comparison to weight-of-evidence studies at other river systems in Southern Germany, the Neckar is characterized by an elevated embryotoxic but by a relatively moderate genotoxic potential. Conclusions The ecotoxicological burden of sediments at the Lower Neckar River is mirrored in the condition of native fish populations. A potential contribution of chemical contamination to the phenomenon of fish declines in aquatic ecosystems cannot be ignored. Recommendations and perspectives The improvement of the ecological status of freshwater systems may not be abused as an argument to discontinue biological monitoring programs. Rather, continuous surveillance of the environment and in-depth investigations into the consequences of chemical contamination are indispensible. For an adequate appreciation of the ecological relevance of sublethal and/or specific biological effects, their impact on population structure and function remains to be elucidated further. For the identification of the chemical basis of biological effects, methodologies such as effect-directed analysis appear to be promising approaches.     

Toxizität und Risk Assessment fluvialer Sedimente und Schwebstoffe: Eine kurze Übersicht bisheriger und neuerer Entwicklungen

Background In recent years, sediments have become a central topic of scientific and public discussion as an important factor for determining water quality. While the quality of surface waters in Germany has significantly improved during the past years, highly contaminated sediments still create a considerable threat to the quality of several European catchment areas. Main features Here, we summarize different concepts and methods for the assessment of sediment quality and report on some novel integrative test methods for assessing sediment toxicity including contaminant re-mobilization during simulated re-suspension events. Results and discussion Currently, different approaches for assessment of sediment pollution exist. While instrumental chemical analyses are not suitable to accurately describe sediment toxicity, combinations of biological and chemical test procedures and integrated approaches, for example weight-of-evidence studies and effect-directed analysis (EDA), have the potential to identify key contaminants. Inter-disciplinary studies combining hydrodynamic and toxicological aspects coupled to real exposure of aquatic organisms to contaminants are currently being developed. Conclusions Monitoring and assessment of sediment quality are of increasing importance, not only for national legislation but also for the implementation of the European Water Framework Directive (WFD). Integrated approaches for the determination of sediment stability play a key role in the appropriate sediment-monitoring strategies.     

Wasserrahmenrichtlinie — Fortschritte und Defizite

Background

The water protection policy of the European Union sits on new footings since the end of 2000: The Water FrameworkDirective (WFD). By replacing, merging and renewing all parts of the European water protection policy from the 1970s, the WFD provides a consistent, transparent and comprehensive concept of what water management should be in the Europe of the coming decades. The new directive is aimed at a holistic approach towards integrated water protection. It sets ambitious high-quality goals to achieve a good status for European lakes and rivers primarily in ecological terms, gives details about the essential processes as well as instruments, and includes everything into a strict time schedule.

Aim

This article adresses progress and shortcomings at the implementation of the WFD in general and with reference to two selected case studies (Rivers Elbe and Upper Danube).

Results and Discussion

After introducing the WFD, its aims and exceptions, a policy summary and background document ‘Environmental objectives und the Water Framework Directive’ and the use of Environmental Quality Standards (EQS) for single ‘priority substances’ as well as ‘hazardous priority components’ is discussed. The initial characterization undertaken by the German states revealed that only about 14% of all surface waters are considered to meet the WFD objectives by the year of 2015. Approximately 60% of the water bodies assessed are at risk of failing the WFD objectives, if not systematic efforts are made to improve the quality. Screenings of sources and paths of exposure for ‘priority substances’ and ‘priority hazardous substances’ according WFD identified one distinct pollution source for surface waters: ‘Historical pollution from sediments’. Because of industrial emissions in the past several river catchment areas are expected to fail the standards demanded by the WFD, due to a risk of remobilization of contaminants from sediments. This holds true for the Rhine river with high loads of hexachlorobenzene (HCB) as well as for Elbe river, where contaminated sediments can be a severe problem. Therefore, integration of sediments into the holistic river basin management approach and their consideration within the ‘programmes of measures’ scheduled for 2009 is highly recommended. At present, a comprehensive weight-of-evidence study verifies whether the observed fish decline at the Upper Danube. River is caused by ecotoxicological hazard potentials of contaminated sediments.

Outlook

Combined investigations of sediment contamination and mobility as well as acute and mechanism specific biotests in effect directed analyses/weight-of-evidence studies show grent potential for the assessment of chemically polluted rivers and should be included into the ‘programmes of measures’ within future management concepts.

     

Ökotoxikologische und humantoxikologische Risikobewertung PAK-belasteter Böden vor und nach biologischer Behandlung

The goal of the present work is to assess the adverse effects of soil bound polycyclic aromatic hydrocarbons (PAH) which remain in soils after biological remediation. We focus on risk assessment for mammalian species with respect to the oral uptake of contaminated soil particles and compare the results of a biomarker test with those of an ecotoxicological assay, the bioluminescence inhibition test withVibrio fischeri. As a biomarker effect in mammals, we determined the liver microsomal cytochrome P450 enzyme CYP1A1 which is induced by PAH in exposed rats. After biological soil treatment, different amounts of PAH remain in the soil depending on the soil properties and initial pollutant composition. Particularly, higher condensated PAH resists biological treatment due to its hydrophobicity. In addition, high amounts of organic carbon in the soils affect remediation efficiency. In the bioluminescence inhibition test, eluates of all biologically treated soils studied do not reveal any or only low inhibitory effects. In contrast, the oral uptake of biologically treated contaminated soils leads to induction levels for CYP1A1 similar to those in the untreated samples. A good correlation is obtained between CYP1A1 levels and the amount of 5 and 6-ring PAH in the soil samples. The main result is that the remediation efficiency determined by the luminescence test is not reflected by the biomarker test, a finding which indicates the high bioavailability of residual PAH in soils. Consequently, new criteria for human risk assessment can be delineated.     

Existierende dioxininventare weltweit und neue methodik zur erstellung von vergleichbaren und vollständigen emissionsinventaren

Presently, there are less than 20 inventories to estimate releases of dioxins and furans. According to a recent survey, 12,900 g TEQ of these unwanted byproducts are emitted into the atmosphere by 16 countries. Highest emissions are from the densely populated industrialized countries of the Northern hemisphere — Japan and the United States of America. Whereas the metal producing and recycling industry is the sector with the highest dioxin emissions in Europe, waste incineration is considered to be the major source in many other countries. Measures to reduce dioxin emissions have resulted in strong downward trends, as shown e.g. in Germany and Japan; however, potentials for further reduction have been identified. So far, countries have utilized own methods to calculate their dioxin emissions and the majority has addressed releases to air only. The future Stockholm Convention on POPs will require to continuously reduce dioxin emissions. In order to assist countries in inventory making, UNEP has produced the Toolkit, a methodology to establish comparable dioxin inventories that address releases to air, water and land, with products and in residues.     

Flächenauswahl und Ökosystemares Monitoring in den Biosphärenreservaten Schorfheide-Chorin und Spreewald

For the two biosphere-reserves of Schorfheide-Chorin and Spreewald in the Federal State of Brandenburg, Germany, we designed a concept for a monitoring program of ecosystems which is feasible and inexpensive, and whose methodical development is transferable to other large-scale protected areas. Beside the statistical analysis of hard GIS data, we systematically used additional criteria such as naturalness, scarcity and special management, a based on expert knowledge. Thus, after an inventory of the existing ecosystems, we selected the ecosystems to be monitored from the different ecosystem groups (i.e. woods and forests, fens, lakes, rivers, arable land and grasslands) based on the following four criteria:

1. dominance,
2. naturalness,
3. nation-wide scarcity and
4. special management.

We then combined the selected ecosystems with their relevant forms of landuse to so-called ecosystem-landuse-complexes, which reflect the natural conditions as well as the human impact in the biosphere reserves. This paper presents the selection of the ecosystem landuse complexes to be monitored. Thus, for both biosphere reserves, we obtained 32 ecosystem landuse complexes in woods and forests, 32 in fens, 53 in lakes, 7 in rivers, 23 in grasslands and 20 in arable land.     

Verteilung und Abnahme von bodennahem Ozon in städtischen und ländlichen Regionen

The compilation of ozone data for the federal states of Hesse and Northrhine-Westphalia (NRW) in Germany indicated that the concentration of ozone level slightly decreased during the years 1990–1998. The average concentration of ozone over forest areas is significantly higher than over cities. Only the maximum figures in the years approached one another. However, values passing the legal thresholds (180 μg ozone/m³) were two to three-fold higher over forests than over cities. The ozone concentration in air is inversely proportional to the traffic density. It is suggested that the lower NOx concentration over the forest than over cities is involved in the maintenance of the higher ozone-concentration over forest areas. In the cities, the ozone is reduced by NO to almost zero at night, whereas it is reduced by only about 50% over forests with lower NO concentrations. This reduction is only partially compensated in connection with the photolysis of NO₂ and the subsequent oxidation of O₂ to O₃ during the day. The ozone situation is principally the same in the federal states of Hesse and Northrhine-Westphalia.     

Abschätzung des umweltchemischen und ökotoxikologischen Verhaltens von Stoffen durch computergestützte Analyse von Struktur und Verhalten sowie von Struktur und Wirkung

Risk assessment of chemicals requires comprehensive data material, which often is not available. To provide substitutes for the lacking experimental ecotoxicological and physico-chemical data, a software-system (SAR-System) has been developed comprising more than 90 estimation models for relevant endpoints. The approach is based on quantitative structure-activity relationships (QSAR). Two major aspects characterize the SAR-System:

1. The implemented models were tested for their validity and application range.
2. The QSARs are accessible by a menu-driven programme package.

The following endpoints are included: Thysico-Chemical Data: 1-Octanol/water-partition-coefficient log P_ow, vapour pressure, water solubility, pK_a-value, boiling point Biological Data: Toxicity towards fish, daphnia, tetrahymenae, algae, bacteria and mammals, mutagenicity. Distribution: soil sorption, bioconcentration, Henry-Constant, Mackay (Level I). Degradation: photodegradation, biodegradability.     

Messung und Quantifizierung von Mineralölkohlenwasserstoffen

Investigations concerning the measurement and evaluation of mineral oil hydrocarbons using Fourier-transform-infrared (FT/IR-)-spectroscopy,¹H-Nuclear magnetic resonance (¹H-NMR)-spectroscopy and Capillary gas chromatography — Flame ionisation detection (GC-FID) are presented. By means of various mineral oils and three certified reference materials (CRM) all tested methods were within a ±7%-range to the mineral oil nominal value and the 95% confidence intervals of the CRM’s, respectively. The GC-FID evaluation could be done without calibration using an relative response ratio of mineral oil to an internal standard (n-tetracontane). A¹H-NMR-method was developed for the quantitative determination of mineral oil hydrocarbons, successfully applied down to 0.2 mg/ml. Due to the determination limit achieved, the¹H-NMR-spectroscopy gain in importance as a reference method for the analysis of mineral oils.     

Trendanalysen mit Mann-Kendall-Test und Theil-Schätzer

Goal and Scope

An extension for trend analysis with Mann Kendall test and Theil estimator is presented which enables the weighting of data by weight factors.

Methods

It is shown in which way the weighting can effect the outcome of a trend analysis. Weighting is done in relation to the different sample sizes of the data points. A value or an observation derived from many specimens will be considered more reliable than a value derived from only a few specimens and will thus get a higher weighting factor.

Results

When weighting is applied, this will effect the Theil estimator rather than the Mann Kendall test. As a result the regression line is tilted towards those points with higher weights.

Outlook

Future must show whether the extensions presented here and in part 1 prove to be practical for the trend analysis in environmental monitoring or not.     

Trendanalysen mit Mann-Kendall-Test und Theil-Schätzer

Goal and Scope

The influence of the measurement uncertainty on the outcomes of statistical evaluations is shown.

Methods

Examplarily using data from the Environmental Specimen Bank the influence of measurement uncertainties on results of trned analyses (Mann Kendall test and Theil estimator) was tested. Both, the simple and the double measurement uncertainty were tested, as well as the standard deviation of repeated measurements.

Results

Considering measurement uncertainty means that not points but intervals are used. A value y_j is then considered larger [smaller] than y_i if applies: y_j-u(y_j>y_i+u(y_i) [y_j+u(y_j)<y_i-u(y_j)], where u(y_j) and u(y_i) are measurement uncertainties of y_j and y_i. Mann Kendall test of trend will react more conservatively (in sense of the maintenance of null hypothesis: no trend), when measurement uncertainties are considered. Thus, the resulting trend statements will be safer.

Outlook

For future application a decision is neccessary about the kind of the measurement uncertainty to be used (none, simple, double, standard deviation). Part 2 will deal with weighting of the data.     

Aktuelle Aerosoltrends an der GAW Globalstation Hohenpeißenberg und ihre Relevanz für Luftreinhaltung und Klima

Aim and Scope

This study was aimed at representing current aerosol trends measured at the GAW global station and their relevance for the present fine dust discussion and a possible impact on climate.

Results and Discussion

1) The intensive GAW measuring program at Hohenpeissenberg covers numerous parameters for the characterization of the physical, optical and chemical characteristics of the atmospheric aerosol. The time series of the number concentration of ultra fine particles with diameters of about 0.004 to 3 μm shows an increase of about 50% since 1995. 2) The introduction of soot particle filters would lower the dust mass only slightly since soot particles from diesel cars only about 8–10% contribute to the dust mass, but about 90% to the number concentration of particles. 3) The single scattering albedo (SSA) is a key parameter determining whether the existing aerosol mixture causes a cooling (negative radiative forcing) or a warming (positive radiative forcing) in the atmosphere. At Hohenpeißenberg the SSA changed from 0.85 to 0.91 in the time period 1999 to 2005, i.e. the regional aerosol as a whole is dominated by scattering rather than absorbing particles.

Conclusion and Perspective

From current aerosol trends at the GAW global station Hohenpeißenberg it was possible to analyze their relevance for air pollution control and possible influences on climate. Dust mass is not a suitable parameter for accessing the contribution of diesel engined vehicles. Measuring the number concentration of particles much more reflects the influence of diesel engined vehicles and also shows, as expected, an upward trend due to a strong increase of the fraction of diesel vehicles in comparison to the total number of cars. Aerosol particles scatter and absorb solar radiation and thus cause a cooling or warming in the atmosphere. Calculated values of the single scattering albedo at Hohenpeissenberg show, that in the initial years the aerosol did not diminish the temperature rise, but rather caused it to increase. Only a data comparison from a global network like GAW can demonstrate, if the results are even representative for the large scale situation.