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Deperissement des forets en Suisse: etat de situation, analyse des causes, projections.
1985
Schuetz J.P.
Assessment of ozone air pollution injuries on forest vegetation in the Transalpine region of Lombardy (Italy) and Canton Ticino (Switzerland)
2002
Ballarin-Denti, A. (Universita Cattolica di Brescia, Brescia (Italy). Dip. Matematica e Fisica) | Bussotti, F. | Cozzi, A. | Krauchi, N. | Gerosa, G. | Schaub, M. | Skelly, J. M. | Tagliaferri, A.
Many previous studies evidenced very high levels of air pollution by ozone between the North Italy (Lombardy) and the Southern Switzerland (Canton Ticino). These levels are mostly attributed to the influence of the large urbanized area of Milan and to the urban and industrial settlements in the Po Valley. Recent researches revealed the existence of spread foliar ozone-like symptoms in many native plant species, both in the Swiss and in Italian sector. Experiments carried out in open top chambers in Canton Ticino allowed us to attribute the foliar symptoms to the ambient air pollution levels
Afficher plus [+] Moins [-]Soil acidification in Swiss forest ecosystems
2002
Braun, S. (Institute for Applied Plant Biology, Schonenbuch, (Switzerland)) | Kurz, D. | Fluckiger, W.
Soil water measurements in Swiss forest plots show a decrease of the ratio between base cations and aluminium within last 4 years. The decrease is significant in at least one soil layer in 12 of 14 plots and is strongest in areas with high acid deposition. In some of the soils the critical ratio of 1 is being reached today. The development is compared with model estimates. In Switzerland, 80% of acid deposition is made up by nitrogen compounds
Afficher plus [+] Moins [-]Modelling local nanobiomaterial release and concentration hotspots in the environment
2021
Hauser, Marina | Nowack, Bernd
Nanobiomaterials (NBMs) are a special category of nanomaterials used in medicine. As applications of NBMs are very similar to pharmaceuticals, their environmental release patterns are likely similar as well. Different pharmaceuticals were detected in surface waters all over the world. Consequently, there exists a need to identify possible NBM exposure routes into the environment. As the application of many NBMs is only carried out at specific locations (hospitals), average predicted environmental concentrations (PECs) may not accurately represent their release to the environment. We estimated the local release of poly(lactic-co-glycolic acid) (PLGA), which is investigated for their use in drug delivery, to Swiss surface waters by using population data as well as type, size and location of hospitals as proxies. The total mean consumption of PGLA in Switzerland using an explorative full-market penetration scenario was calculated to be 770 kg/year. 105 hospitals were considered, which were connected to wastewater treatment plants and the receiving water body using graphic information system (GIS) modelling. The water body dataset contained 20,167 river segments and 210 lake polygons. Using the discharge of the river, we were able to calculate the PECs in different river segments. While we calculated high PLGA releases of 2.24 and 2.03 kg/year in large cities such as Geneva or Zurich, the resulting local PECs of 220 and 660 pg/l, respectively, were low due to the high river discharge (330 and 97 m³/s). High PLGA concentrations (up to 7,900 pg/l) on the other hand were calculated around smaller cities with local hospitals but also smaller receiving rivers (between 0.7 and 1.9 m³/s). Therefore, we conclude that population density does not accurately predict local concentration hotspots of NBMs, such as PLGA, that are administered in a hospital context. In addition, even at the locations with the highest predicted PLGA concentrations, the expected risk is low.
Afficher plus [+] Moins [-]Dynamic probabilistic material flow analysis of nano-SiO2, nano iron oxides, nano-CeO2, nano-Al2O3, and quantum dots in seven European regions
2018
Wang, Yan | Nowack, Bernd
Static environmental exposure assessment models based on material flow analysis (MFA) have previously been used to estimate flows of engineered nanomaterials (ENMs) to the environment. However, such models do not account for changes in the system behavior over time. Dynamic MFA used in this study includes the time-dependent development of the modelling system by considering accumulation of ENMs in stocks and the environment, and the dynamic release of ENMs from nano-products. In addition, this study also included regional variations in population, waste management systems, and environmental compartments, which subsequently influence the environmental release and concentrations of ENMs. We have estimated the flows and release concentrations of nano-SiO₂, nano-iron oxides, nano-CeO₂, nano-Al₂O₃, and quantum dots in the EU and six geographical sub-regions in Europe (Central Europe, Northern Europe, Southern Europe, Eastern Europe, South-eastern Europe, and Switzerland). The model predicts that a large amount of ENMs are accumulated in stocks (not considering further transformation). For example, in the EU 2040 Mt of nano-SiO₂ are stored in the in-use stock, 80,400 tonnes have been accumulated in sediments and 65,600 tonnes in natural and urban soil from 1990 to 2014. The magnitude of flows in waste management processes in different regions varies because of differences in waste handling. For example, concentrations in landfilled waste are lowest in South-eastern Europe due to dilution by the high amount of landfilled waste in the region. The flows predicted in this work can serve as improved input data for mechanistic environmental fate models and risk assessment studies compared to previous estimates using static models.
Afficher plus [+] Moins [-]Spatial variability of methane: Attributing atmospheric concentrations to emissions
2014
Bamberger, I. | Stieger, J. | Buchmann, N. | Eugster, W.
Atmospheric methane concentrations were quantified along transects in Switzerland, using a mobile laser spectrometer combined with a GPS, to identify their spatio-temporal patterns and their controlling factors. Based on these measurements in complex terrain dominated by agriculture, three main factors were found to be responsible for the diurnal and regional patterns of atmospheric methane: (1) magnitude and distribution of methane sources within the region, (2) efficiency of vertical exchange, and (3) local wind patterns within the complex topography. An autocorrelation analysis of measured methane concentrations showed that nighttime measurements close to the ground provide information about regional sources (up to 8.3 km), while daytime measurements only carry information about sources located up to 240 m away in the upwind fetch. Compared to daytime concentrations, nighttime methane concentrations do also better reflect emissions obtained from a spatially explicit methane emission inventory and allowed the investigation of inconsistencies in this emission inventory.
Afficher plus [+] Moins [-]A dynamic modelling approach for estimating critical loads of nitrogen based on plant community changes under a changing climate
2011
Belyazid, Salim | Kurz, Dani | Braun, Sabine | Sverdrup, Harald | Rihm, Beat | Hettelingh, Jean-Paul
A dynamic model of forest ecosystems was used to investigate the effects of climate change, atmospheric deposition and harvest intensity on 48 forest sites in Sweden (n = 16) and Switzerland (n = 32). The model was used to investigate the feasibility of deriving critical loads for nitrogen (N) deposition based on changes in plant community composition. The simulations show that climate and atmospheric deposition have comparably important effects on N mobilization in the soil, as climate triggers the release of organically bound nitrogen stored in the soil during the elevated deposition period. Climate has the most important effect on plant community composition, underlining the fact that this cannot be ignored in future simulations of vegetation dynamics. Harvest intensity has comparatively little effect on the plant community in the long term, while it may be detrimental in the short term following cutting. This study shows: that critical loads of N deposition can be estimated using the plant community as an indicator; that future climatic changes must be taken into account; and that the definition of the reference deposition is critical for the outcome of this estimate.
Afficher plus [+] Moins [-]Modeling short-term variability of semivolatile organic chemicals in air at a local scale: An integrated modeling approach
2011
Morselli, Melissa | Ghirardello, Davide | Semplice, Matteo | Di Guardo, Antonio
Monitoring campaigns from different locations have recently shown how air concentrations of persistent semivolatile contaminants such as polychlorinated biphenyls (PCBs) often exhibit short-term (less than 24 h) variations. The observed patterns have been ascribed to different factors, such as temperature-mediated air–surface exchange and variability of planetary boundary layer (PBL) height and dynamics. Here, we present a new modeling approach developed in order to investigate the short-term variability in air concentrations of organic pollutants at a local scale. A new dynamic multimedia box model is supplied by a meteorological preprocessor (AERMET) with hourly values of air compartment height and wind speed. The resulting model is tested against an existing dataset of PCB air concentrations measured in Zurich, Switzerland. Results show the importance of such modeling approach in elucidating the short- and long-term behavior of semivolatile contaminants in the air/soil system.
Afficher plus [+] Moins [-]Identification of perfluoroalkyl acid sources in Swiss surface waters with the help of the artificial sweetener acesulfame
2011
Müller, Claudia E. | Gerecke, Andreas C. | Alder, Alfredo C. | Scheringer, Martin | Hungerbühler, Konrad
Anthropogenic perfluorinated compounds (PFCs), especially the perfluoroalkyl acids (PFAAs) are ubiquitously found in surface waters around the globe. Emissions from households, industries and also atmospheric transport/deposition are discussed as the possible sources. In this study, these sources are evaluated using Switzerland as the study area. Forty-four surface water locations in different rivers and an Alpine lake were investigated for 14 PFAAs, four precursors and acesulfame, an artificial sweetener used as a population marker. Concentrations of individual PFAAs were generally low, between 0.02 and 10 ng/L. Correlation analysis showed that some PFAAs concentrations correlated well with population and less with catchment area, indicating that emissions from population, i.e., from consumer products, is the most important source to surface waters in Switzerland. The correlation with the population marker acesulfame confirmed this observation but highlighted also a few elevated PFAA levels, some of which could be attributed to industrial emissions.
Afficher plus [+] Moins [-]Long-chain perfluorinated chemicals in digested sewage sludges in Switzerland
2011
Sun, Hongwen | Gerecke, Andreas C. | Giger, W. (Walter) | Alder, Alfredo C.
This study focused on the occurrence of long-chain perfluorinated chemicals (PFCs) in anaerobically stabilized sewage sludges from 20 municipal WWTPs using current and historic samples to evaluate the levels of PFCs and to identify the relative importance of commercial and industrial sources. A quantitative analytical method was developed based on solvent extraction of the analytes and a LC-MS/MS system. For total perfluoralkyl carboxylates (PFCAs), the concentrations ranged from 14 to 50μg/kg dry matter. Concentrations of perfluorooctane sulfonic acid (PFOS) ranged from 15 to 600μg/kg dry matter. In three WWTPs, the PFOS levels were six to nine times higher than the average values measured in the other plants. These elevated PFOS concentrations did not correlate with higher levels of PFCAs, indicating specific additional local sources for PFOS at these WWTPs. Average concentrations in selected samples from the years 1993, 2002, and 2008 did not change significantly.
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