Schafer K.,Karlsruhe Institute of Technology |
Thomas W.,Meteorological Observatory HPB |
Peters A.,Helmholtz Center for Environmental Research |
Ries L.,Federal Environmental Agency UBA |
And 23 more authors.
Atmospheric Chemistry and Physics | Year: 2011
A series of major eruptions of the Eyjafjallajökull volcano in Iceland started on 14 April 2010 and continued until the end of May 2010. The volcanic emissions moved over nearly the whole of Europe and were observed first on 16 April 2010 in Southern Germany with different remote sensing systems from the ground and space. Enhanced PM10 and SO2 concentrations were detected on 17 April at mountain stations (Zugspitze/Schneefernerhaus and Schauinsland) as well as in Innsbruck by in situ measurement devices. On 19 April intensive vertical mixing and advection along with clear-sky conditions facilitated the entrainment of volcanic material down to the ground. The subsequent formation of a stably stratified lower atmosphere with limited mixing near the ground during the evening of 19 April led to an additional enhancement of near-surface particle concentrations. Consequently, on 19 April and 20 April exceedances of the daily threshold value for particulate matter (PM10) were reported at nearly all monitoring stations of the North Alpine foothills as well as at mountain and valley stations in the northern Alps. The chemical analyses of ambient PM10 at monitoring stations of the North Alpine foothills yielded elevated Titanium concentrations on 19/20 April which prove the presence of volcanic plume material. Following this result the PM10 threshold exceedances are also associated with the volcanic plume. The entrainment of the volcanic plume material mainly affected the concentrations of coarse particles (>1 μm)-interpreted as volcanic ash-and ultrafine particles (<100 nm), while the concentrations of accumulation mode aerosol (0.1-1 μm) were not changed significantly. With regard to the occurrence of ultrafine particles, it is concluded that their formation was triggered by high sulphuric acid concentrations which are necessarily generated by the photochemical processes in a plume rich in sulphur dioxide under high solar irradiance. It became evident that during the course of several days, the Eyjafjallajökull volcanic emissions influenced the near-surface atmosphere and thus the ambient air quality. Although the volcanic plume contributed to the overall exposure of the population of the northern Alpine region on two days, only minor effects on the exacerbation of respiratory and cardiovascular symptoms can be expected. © 2011 Author(s).
Schafer K.,Karlsruhe Institute of Technology |
Birmili W.,Leibniz Institute for Tropospheric Research |
Cyrys J.,Helmholtz Center for Environmental Research |
Emeis S.,Karlsruhe Institute of Technology |
And 6 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010
The Eyjafjallajökull volcano eruptions during mid April 2010 influenced European air traffic basically. This was mainly due to the low melting point of ejected material and the sharp-edged form of particles. As there is the necessity to understand the dispersion of such an ash cloud we assess the existing measurement networks and evaluate the existing numerical models (MCCM). We use data from ceilometers to detect the vertical distribution of the volcanic cloud. Ground-based in situ measurements of particle concentrations, sulphur dioxide and further parameters complete the data basis. The analysis concentrates on the spatial and temporal features of the event over Southern Germany. It is an initiative of a scientific cooperation on aerosols in the area of Augsburg (500 m altitude) - Munich (550 m) - Hohenpeiß enberg (1000 m) - Zugspitze / Schneefernerhaus (2650 m). The period from the evening of April 15th to the evening of April 20th, 2010 is covered. Main emphasis is laid on shorter events: (1) the first 15 hours of April 17th when the first cloud moved over Southern Germany, (2) the night from April 17th to April 18th when a second puff arrived over Southern Germany, and (3) the afternoon of April 19th when another puff arrived over Southern Germany. Back trajectories are used to check the origin of the observed dust clouds. Results from the model simulations with MCCM for the whole period will be compared with the measurement results. We will draw conclusions about the predictability of such events, the abilities of numerical models, the possible relevance for near-surface air quality as well as the possible enhancements of existing observation networks and simulation systems.
Egeler P.,ECT Oekotoxikologie GmbH |
Henry K.S.,Dow Chemical Company |
Henry K.S.,Syngenta |
Riedhammer C.,Federal Environmental Agency UBA
Journal of Soils and Sediments | Year: 2010
Purpose: Standardized sediment toxicity assays often employ periodic additions of uncontaminated food to sustain energy and growth requirements of the test organisms. Consequently, selective feeding on this uncontaminated food may reduce exposure to sediment particles containing the test substance. To address this issue, some standard guidelines propose to add food to the sediment before spiking with the test substance to account for multiple exposure routes, including ingestion of contaminated food. The present study focused on the influence of different feeding regimens and compositions of the aqueous medium on water quality (ammonia concentrations) and test organism development. Materials and methods: Lumbriculus variegatus, Hyalella azteca, and Chironomus riparius larvae were used as test organisms. Ammonia production was investigated under different feeding regimens and test conditions as well as under the presence of a potential inhibitor of nitrification, 4,4'-methylenedianiline. Results and discussion: Ammonia concentrations strongly depended on the feeding regimen and on the type of food. An influence of 4,4'-methylenedianiline on test organisms or ammonia concentrations was not found at the tested level. Independently of ammonia concentrations, L. variegatus were more sensitive to food type and less sensitive to medium composition than H. azteca. Ammonia levels, emergence ratio, and development rate of C. riparius were not different under periodic feeding and single addition of Urtica. Findings suggest that in case of a "sediment-incorporated" feeding regimen, the time point of food addition to the sediment and careful pH control appear critical. For H. azteca and L. variegatus, an Urtica/cellulose mixture provides a balance between ammonia production and organism development. Conclusions: This article gives recommendations and caveats for conducting spiked-sediment tests with a single addition of sediment-incorporated food. The presented work also contributed to the development of two recently adopted OECD test guidelines related to sediment toxicity and bioaccumulation testing with endobenthic oligochaetes. © Springer-Verlag 2010.
Wicke D.,KompetenzZentrum Wasser Berlin |
Rouault P.,KompetenzZentrum Wasser Berlin |
Camilo B.K.,Federal Environmental Agency UBA |
Pagotto C.,Pirelli SpA |
And 2 more authors.
Water Science and Technology: Water Supply | Year: 2015
Diffuse nitrate (NO3) contamination from intense agriculture adversely impacts freshwater ecosystems, and can also result in nitrate concentrations exceeding limits set in drinking water regulation, when receiving surface waters are used for drinking water production. Implementation of near-natural mitigation zones such as reactive swales or wetlands have been proven to be promising measures to reduce nitrate loads in agricultural drainage waters. However, the behavior of these systems at low temperatures and its dependence on system design has not beenwell known until now. In this study, the behavior of a full-scale (length: 45 m) reactive swale treating drainage water from an agricultural watershed in Brittany (France), with high nitrate concentrations in the receiving river, was monitored for one season (6 months). As flow in this full-size field system is usually restricted to winter and spring months (December-May), itusually operates at low water temperatures of 5-10 °C. Tracer tests revealed shorter than designed retention times due to high inflows and preferential flow in the swale. Results show a correlation between residence time and nitrate reduction with low removal (<10%) for short residence times (<0.1 day), increasing to >25% at residence times >10 h (0.4 day). Performance was compared to results of two technical-scale reactive swales (length: 8 m) operated for 1.5 years with two different residence times (0.4 and 2.5 days), situated at a test site of the German Federal Environmental Agency in Berlin (Germany). Similar nitrate reduction was observed for comparable temperature and residence time, showing that up-scaling is a suitable approach to transferring knowledge gathered from technical-scale experiments to field conditions. For the design of new mitigation systems, one recommendation is to investigate carefully the expected inflow volumes in advance to ensure a sufficient residence time for effective nitrate reduction at low temperatures. © IWA Publishing 2015.
Litz N.T.,Federal Environmental Agency UBA |
Weigert A.,TU Dresden |
Krause B.,Federal Environmental Agency UBA |
Heise S.,Federal Environmental Agency UBA |
Grutzmacher G.,KompetenzZentrum Wasser Berlin
Water Research | Year: 2011
The herbicide Glyphosate was detected in River Havel (Berlin, Germany) in concentrations between 0.1 and 2 μg/L (single maximum outlier: 5 μg/L). As the river indirectly acts as drinking water source for the city's 3.4 Mio inhabitants potential risks for drinking water production needed to be assessed. For this reason laboratory (sorption and degradation studies) and technical scale investigations (bank filtration and slow sand filter experiments) were carried out. Batch adsorption experiments with Glyphosate yielded a low KF of 1.89 (1/n = 0.48) for concentrations between 0.1 and 100 mg/L. Degradation experiments at 8 °C with oxygen limitation resulted in a decrease of Glyphosate concentrations in the liquid phase probably due to slow adsorption (half life: 30 days).During technical scale slow sand filter (SSF) experiments Glyphosate attenuation was 70-80% for constant inlet concentrations of 0.7, 3.5 and 11.6 μg/L, respectively. Relevant retardation of Glyphosate breakthrough was observed despite the low adsorption potential of the sandy filter substrate and the relatively high flow velocity. The VisualCXTFit model was applied with data from typical Berlin bank filtration sites to extrapolate the results to a realistic field setting and yielded sufficient attenuation within a few days of travel time. Experiments on an SSF planted with Phragmites australis and an unplanted SSF with mainly vertical flow conditions to which Glyphosate was continuously dosed showed that in the planted SSF Glyphosate retardation exceeds 54% compared to 14% retardation in the unplanted SSF. The results show that saturated subsurface passage has the potential to efficiently attenuate glyphosate, favorably with aerobic conditions, long travel times and the presence of planted riparian boundary buffer strips. © 2011 Elsevier Ltd.