über Bilche oder ?Schl?fer’: Gartenschl?fer, Baumschl?fer, Siebenschl?fer und Haselm?use

Ohne Zusammenfassung     

The dissipation,distribution and fate of a branched 14C-nonylphenol isomer in lake water/sediment systems

A single tertiary isomer which is believed to be one of the major branched isomers of the isomeric nonylphenol was synthesized for use in investigations on its metabolism and estrogenicity in aquatic organisms. The physico-chemical properties of the isomer were determined to enable the prediction of its behaviour in aquatic environments. From laboratory investigations on its dissipation and distribution in lake water, which are reported in this paper, it was found that it had a half-life of dissipation of 38.1 days and 20.1 days in an open lake water and in an open lake water/ sediment system, respectively, and to be rapidly partitioned in to sediment giving a high concentration factor of 1.76 after 28 days with an initial dose concentration of 2.52 ppm. The main dissipation route was found to occur through volatilization and co-distillation. The isomer was, however, found to be resistant to biodegradation in both the lake water and sediment, showing only a slight 9% loss (after 56 days) and 4.2% loss (after 28 days), of the 14C-residues in lake water and lake water/sediment systems, respectively, by microbial activity. Transformation to other more polar metabolites possibly by hydroxylation was also found to be minimal in both lake water and sediment samples after 14 days by HPLC analysis. After 7 days, only 2.25 and 7.4% transformation to a more polar metabolite was detected in lake water and sediment samples, respectively.     

Validation of leaf ozone symptoms in natural vegetation using microscopical methods

Ozone injury to natural vegetation is being increasingly surveyed throughout the northern hemisphere. There exists a growing list of species showing visible 'ozone-like' symptoms which needs to be validated. This study presents the results from a test survey of ozone injury to forest vegetation in the light exposed sites of five Swiss level II plots, for the new ICP-Forests protocol. With AOT40 from 14 to 28 ppm-h in 2000, ten out of 49 woody plant species displayed typical symptoms, and four showed untypical symptoms. Symptom origin was investigated in nine and validated in seven species, using morphological, histological and cellular markers of oxidative stress and ozone-induced plant response. Independent of taxonomic position, ozone effects were characterized by the induction of oxidative stress in the mesophyll resulting in discrete and light-dependent hypersensitive-like responses and in accelerated cell senescence. The presented combination of cellular and morphological markers allows differential diagnosis of visible ozone injury.     

Umwelt und Nachhaltigkeit im Jahr der Chemie

Ohne Zusammenfassung     

Performance of the Button Personal Inhalable Sampler for the measurement of outdoor aeroallergens

No personal aerosol sampler has been evaluated for monitoring aeroallergens in outdoor field conditions and compared to conventional stationary aerobiological samplers. Recently developed Button Personal Inhalable Aerosol Sampler has demonstrated high sampling efficiency for non-biological particles and low sensitivity to the wind direction and velocity. The aim of the present study was to evaluate the Button Sampler for the measurement of outdoor pollen grains and fungal spores side-by-side with the widely used Rotorod Sampler. The sampling was performed for 8 months (spring, summer and fall) at a monitoring station on the roof of a two-storied office building located in the center of the city of Cincinnati. Two identical Button Samplers, one oriented towards the most prevalent wind and the other towards the opposite wind and a Rotorod Sampler were placed side-by-side. The total fungal spore concentration ranged from 129 to 12,980 spores m(-3) (number per cubic meter of air) and the total pollen concentration from 4 to 4536 pollen m(-3). The fungal spore concentrations obtained with the two Button Samplers correlated well (r = 0.95; p<0.0001). The pollen data also showed positive correlation. These findings strongly support the results of earlier studies conducted with non-biological aerosol particles, which demonstrated a low wind dependence of the performance of the Button Sampler compared to other samplers. The Button Sampler's inlet efficiency was found to be more dependent on wind direction when sampling larger sized Pinaceae pollen grains (aerodynamic diameter approximately 65 mum). Compared to Rotorod, both Button Samplers measured significantly higher total fungal spore concentrations. For total pollen count, the Button Sampler facing the prevalent wind showed concentrations levels comparable to that of the Rotorod, but the Button Sampler oriented opposite to the prevalent wind demonstrated lower concentration levels. Overall, it was concluded that the Button Sampler is efficient for the personal sampling of outdoor aeroallergens, and is especially beneficial for aeroallergens of small particle size.     

Enhanced experimental flexibility and control in ecotoxicological mesocosm experiments--a new outdoor and indoor pond and stream system

Scope The German Federal Environmental Agency has put into operation a new modular mesocosm system consisting of eight outdoor and eight indoor ponds and streams in order to investigate fate and effects of chemicals and municipal wastewater in aquatic ecosystems. General design and special characteristics are given to demonstrate the wide range of possibilities for experimental research. - General design. Each of the 16 streams with riffle and pool sections can be varied in length up to 106 m. The streams can be run as circular or flow-through systems at a flow velocity of 0.02 to 0.6 m/s. Physico-chemical standard parameters are measured on-line. The 16 ponds, which can be connected to the stream systems, are equipped with drainage and pore water-sampling devices for simulating processes in the littoral zone including influent and effluent ground water flow. Perspectives Since the highly flexible and controllable construction also allows treating a wide range of hydrological and ecological experiments external institutions are invited to submit proposals.     

Endocrine disruption of water and sediment extracts in a non-radioactive dot blot/RNAse protection-assay using isolated hepatocytes of rainbow trout

Goal, Scope and Background In order to evaluate the estrogenic activity of sediments and XAD water extracts of selected sites of the catchment area of the River Neckar, a river system in Southern Germany, an integrative assessment approach was used to assess the ecological hazard potential of endocrine-disrupting compounds in sediment and water. Methods The approach is based on estrogen receptor-mediated vitellogenin synthesis induced in isolated hepatocytes of rainbow trout and quantified in a non-radioactive dot blot/RNAse protection-assay in parallel to comprehensive chemical analyses of estrogenic substances. Results and Discussion Numerous investigated extracts revealed an estrogen activity comparable to that of the positive control (1 nM 17?-estradiol corresponding to 270 ng/L in the test medium). Based on a concentration factor of 30 in the extracts and a recovery of XAD resins of approximately 80 %, 17?-estradiol equivalent concentrations between 20 and 26.7 ng/L could be calculated downstream of a sewage treatment plant (< 0.1 ng/L for a reference site). A comparison of the bioassay-derived Bio-TEQs (toxicity equivalents) and the Chem-TEQs revealed a high correlation with a Pearson coefficient of 0.85, indicating that the same ranking of the samples could be obtained with respect to the endocrine disrupting potential with both chemical and bioanalytical analysis. However, the TEQ concentrations computed from chemical analyses were significantly lower than the bioassay-derived TEQ concentrations. In fact, in none of the samples, more than 14 % of the vitellogenin-inducing potency could be attributed to the substances (steroids, alkylphenols, bisphenol A, diethylstilbestrol) analyzed. A comparison of the endocrine disrupting potential of sediments extracted by the solvents acetone and methanol revealed lower biological effects for acetone-extracted samples. Possible reasons may be a masking of endocrine effects in acetone extracts by cytotoxicity, a low extraction efficiency of the solvent acetone, or anti-estrogen potencies of some extracted sediment compounds. Using a mass balance approach, the contribution of the compounds analyzed chemically (Chem-TEQs) to the total endocrine activity (Bio-TEQs) was calculated. Based on the very low detection limits, particularly of the steroids with their high TEF factors, results revealed that a calculation of the Chem-TEQs is associated with considerable scale inaccuracy: Whereas only 7-15 % of the biological effectiveness (Bio-TEQs) could be explained by endocrine substances identified above the detection limits, the assumption of concentrations slightly below the given detection limits would result in a significant over estimation (137-197 %) of the Bio-TEQs. Even the interassay variation of the dot blot assay with different fish donors for primary hepatocyte (factor 2 - 2.5) is relatively low, when compared to the large range of the Chem-TEQ concentrations (factor 20) obtained when applying different modes of calculation. Conclusions and Outlook Overall, only a minor portion of the endocrine activity detected by bioassays could be linked to compounds identified by chemical analysis. In vitro assays for assessment of endocrine activities are useful as sensitive integrating methods that provide quantitative estimates of the total activity of particular receptor-mediated responses. Although discrepancies may also result from different bioanalytical approaches, it is overall likely that bioanalytical and not chemical analytical approaches give the correct estimate of endocrine disrupting potencies in environmental samples. As a conclusion, assessment of endocrine disruption based on chemical analysis alone does not appear sufficient and further research into the spectrum of substances with potential endocrine activity as well as into additive or even synergistic effects in complex environmental samples is urgently needed.     

Practical considerations for addressing uncertainties in monitoring bulk deposition

The assessment of the deposition of both wet (rain and cloud) and dry sedimenting particles is a prerequisite for estimating element fluxes in ecosystem research. Many nations and institutions operate deposition networks using different types of sampler. However, these samplers have rarely been characterized with respect to their sink properties. Major errors in assessing bulk deposition can result from poor sampling properties and defective sampling strategies. Relevant properties are: sampler geometry and material, in particular the shape of the rim; sink properties for gases and aerosols; and microbial transformations of the collected samples. An adequate number of replicates allows the identification of samples which are contaminated, in particular by bird droppings. The paper discusses physical and chemical properties of the samplers themselves. The dependence of measurement accuracy on the number of replicates and the sampling area exposed is discussed. Recommendations are given for sampling strategies, and for making corrections and substitution of missing data.     

A European survey of atmospheric heavy metal deposition in 2000-2001

The background, administration and current status of the monitoring programme "European Survey of Atmospheric Heavy Metal Deposition" is described. All European states are invited to join the survey 2000-2001. The co-ordination and responsibility for the survey will gradually be transferred from the Nordic Council of Ministers to the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation).     

Mercury pollution and macrophage centres in pike (Esox lucius) tissues

From June 1993 to October 1994, studies have been carried out on the effects of mercury in the Oder River and pike tissue contamination (muscle, kidney, liver). The mean mercury contents in the sediment range from 0.03 to 1.1 mg/kg dry weight. In the pike muscle, between 0.22 and 0.85 mg/kg, on a wet weight basis, were found. The measured mercury concentrations were analysed in relation to the number of macrophage centres of the liver, spleen and kidney of the pike. Positive correlations between mercury and MC response (0.54 ≤ r ≤ 0.79, p < 0.05) were found in all of these organs. The suitability of the macrophage-centre-response as a possible bioindicator for mercury pollution is discussed in the literature. In our study, the response of MCs was found to be suitable as a biomarker for the impairment of fish health.