Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity.     

Changes in toxicity and Ah receptor agonist activity of suspended particulate matter during flood events at the rivers Neckar and Rhine — a mass balance approach using in vitro methods and chemical analysis

Background, aim, and scope  

As a consequence of flood events, runoff and remobilized sediments may cause an increase of ecotoxicologically relevant effects from contaminant reservoirs. Aquatic and terrestrial organisms as well as cattle and areas of settlement are exposed to dislocated contaminants during and after flood events. In this study, the impacts of two flood events triggered by intense rain at the rivers Neckar and Rhine (Southern Germany) were studied. Effects in correlation to flood flow were assessed at the river Neckar using samples collected at frequent intervals. River Rhine suspended particulate matter (SPM) was sampled over a longer period at normal flow and during a flood event. Three cell lines (H4L1.1c4, GPC.2D.Luc, RTL-W1) were used to compare Ah receptor agonist activity in different biotest systems. Multilayer fractionation was performed to identify causative compounds, focusing on persistent organic contaminants.     

Foliar contamination of Phaseolus vulgaris with aerosols of 137Cs, 85Sr, 133Ba and 123mTe: influence of plant development stage upon contamination and rain

As part of a requirement to improve the assessment of the impact of radioactive fallout on consumed agricultural products, bean plants at four development stages (seedlings, preflowering, late flowering and mature plants) were contaminated by dry deposition of (137)Cs, (85)Sr, (133)Ba and (123m)Te aerosols. The influence of two rain scenarios and of the development stage upon contamination on interception, retention, and translocation to pods was studied. Interception of the four radionuclides was almost identical and varied from 30 to 60% with increasing development stage. The most important rain parameter was the time which elapsed between contamination and the first rain. Whatever the development stage, rain washed off more cesium from the leaves when it occurred 2 days after the deposit (37% at the seedling stage, for example) rather than later on (6 days, 27%), due to rapid migration of Cs in the plant. The first rain washed off nearly 40% of Ba whatever the scenario. For later stages, Sr and Ba were more washed off by heavy weekly rains than by weak twice-a-week rains, perhaps because of the Sr/Ba-contaminated material loss associated with wash off (desquamation of cuticles). Te showed little wash off (less than 5%). Wash off decreased with an older development stage for a weak rain intensity, due to the superimposition of leaves. Heavy rains removed this shelter effect. At harvest, rain effect was no longer detectable as foliar activity was similar for both rain scenarios. Translocation factors (TF) for strontium and barium increased from 6 x 10(-3) to 1 x 10(-1) with the plant development stage upon contamination, whereas those for cesium remained almost unchanged between 2 x 10(-1) and 4 x 10(-1). Flowering is the most critical stage towards residual contamination in pods at harvest, with the exception of direct deposit on pods at the mature stage (TF values are one order of magnitude higher). TF value for Te was 6.5 x 10(-2) and was due to direct deposit. Modelling reflected the trends, through the differential values of the wash off and absorption coefficients, of what was reported for experimental results.     

Hand in Hand für Interdisziplinarit?t

Ohne Zusammenfassung Dr. rer. nat. Henner Hollert: • Leitung lokales Organisationskomittee SETAC-GLB 2003 • Studium der Biologie und Geographie an der Universit?t Heidelberg von 1990 bis 1997. Februar 1997: Diplom in Biologie, Oktober 1997: Erstes Staatsexamen für das h?here Lehramt in Biologie/Geographie • Von November 1997 bis April 2001: Promotion über die Entwicklung eines kombinierten Untersuchungssystems für die Bewertung der ?kotoxikologischen Belastung von Flie?gew?ssersedimenten und-schwebstoffen • Forschungsaufenthalte 1999 und 2000 an den Universit?ten Uppsala und ?rebro (Schweden) zur Untersuchung der Dioxin-?hnlichen Wirksamkeit von Sedimenten in embryonaler Hühnerleberkultur • In der Lehre seit 2000 als Wissenschaftlicher Angestellter am Zoologischen Institut (Abt. Morphologie/?kologie) mit den Schwerpunkten ?kotoxikologie, ?kologie und Zoologie t?tig • Leitung der Arbeitsgruppe Sediment- und Bodentoxikologie • Forschungsschwerpunkte: Sediment- und Bodentoxikologie, Hochwasseruntersuchunge, Bioassay-dirigierte Fraktionierungstechniken, Statistische Bewertungsmethoden, Integrierte Sedimentuntersuchungen (Kombination aus Makrozoobenthosanalysen, in-vitro-Biotests und chemischer Analytik) • Vizepr?sident der deutschsprachigen Sektion der SETAC-GLB (Society of Environmental Toxicology and Chemistry) • Organisationskomitee der europ?ischen Jahrestagung der SETAC und des Club of Rome in Hamburg-Harburg 2003 • Seit dem 11. Juni 2003 geh?rt Henner Hollert dem UWSF-Herausgebergremium an     

A bioassay approach to determine the dioxin-like activity in sediment extracts from the Danube River: ethoxyresorufin-O-deethylase induction in gill filaments and liver of three-spined sticklebacks (Gasterosteus aculeatus L.)

Sediment samples from the upper Danube River in Germany have previously been characterized as ecotoxicologically hazardous and contaminants in these sediments may contribute to the observed decline of fish populations in this river section. For the investigation of sediment toxicity there is a need for development, standardization and implementation of in vivo test systems using vertebrates. Therefore, the main objective of this study was to apply and evaluate a recently established fish gill EROD assay as a biomarker in sediment toxicity assessment by using extracts of well characterised sediment samples from the upper Danube River. This to our knowledge is the first application of this novel assay to sediment extracts. Sediments from four different sites along the upper Danube River were Soxhlet-extracted with acetone and dissolved in DMSO. Three-spined sticklebacks (Gasterosteus aculeatus L.) were exposed for 48 h to various concentrations of the extracts, to the positive control beta-naphthoflavone or to the solvent. Measurements of EROD activity in gill filaments and liver microsomes followed the exposure. Concentration-dependent induction of EROD in both gill and liver was found for all sediment extracts. The highest EROD-inducing potency was determined for extracts of sediments from the sites "Opfinger See" and "Sigmaringen" and the EROD activities in gill and liver correlated well. The results from the gill and liver assays were in accordance with in vitro results of previous investigations. The EROD activities measured in the present study corresponded with the concentrations of PAHs, PCBs and PCDD/Fs in the sediment samples derived in a previous study. The sticklebacks in this study were in the reproductive phase and a stronger EROD induction was obtained in the females than in the males. Implementation of the EROD assay in testing of sediment extracts gave highly reliable results which make this assay an ecotoxicologically relevant method for assessment of contamination with Ah receptor agonists in sediments.