Chromium (Cr) is introduced into the environment by several anthropogenic activities. A striking ex-ample is the area around Kanpur in the Indian state of Uttar Pradesh, where large amounts of Cr-containing wastes have been recently illegally deposited. Hexavalent Cr, a highly toxic and mobile contaminant, is present in significant amounts in these wastes, severely affecting the quality of sur-roundings soils, sediments, and ground waters. The first major goal of this study is to clarify the solid phase speciation of Cr in these wastes and to examine its leaching behavior. X-ray diffraction and synchrotron-based X-ray absorption spectroscopy techniques will be employed for quantitative solid phase speciation of Cr. Its leaching behavior will be studied in column experiments performed at un-saturated moisture conditions with flow interruptions simulating monsoon rain events. Combined with geochemical modeling, the results will allow the evaluation of the leaching potential and release kinetics of Cr from the waste materials. The second major goal is to investigate the spatial distribution, speciation, and solubility of Cr in the rooting zone of chromate-contaminated soils surrounding the landfills, and to study the suitability of biochar as novel soil amendment for mitigating the deleterious effects of chromate pollution. Detailed field samplings and laboratory soil incubation studies will be carried out with two agricultural soils and biochar from the Kanpur region.
In this project we experimentally explore the transport of engineered inorganic nanoparticles (EINP) through soils. This is done for original EINPs and some pre-aged form. Transport of NPs in soil is expected to be different from that of reactive solutes, in that hydrodynamic drag, inertial and shear forces as well as the affinity to water-gas interfaces are expected to be more relevant. Hence, the mobility of EINPs in soil is highly sensitive to the morphology of the porous structure and the dynamics of water saturation.This project provides the pore network structure for natural soils using X-ray micro-tomography to allow for an up-scaling of pore-scale interactions explored by project partners to the scale of soil horizons. The pore structure is represented by a network model suitable for pore scale simulations including the dynamics of water-gas interfaces.Pore network simulations will be compared to column experiments for conservative tracers as well as for unaltered and pre-aged EINPs (obtained from INTERFACE). This includes steady state flow scenarios for saturated (ponding) and unsaturated conditions as well as for transient flow to explore the impact of moving water-gas interfaces. The final goal is to arrive at a consistent interpretation of experimental findings and numerical simulations to develop a module for modelling EINP transfer through soil as a function of particle properties, soil structural characteristics and external forcing in terms of flux boundary conditions.
The relevance of biogeochemical gradients for turnover of organic matter and contaminants is yet poorly understood. This study aims at the identification and quantification of the interaction of different redox processes along gradients. The interaction of iron-, and sulfate reduction and methanogenesis will be studied in controlled batch and column experiments. Factors constraining the accessibility and the energy yield from the use of these electron acceptors will be evaluated, such as passivation of iron oxides, re-oxidation of hydrogen sulfide on iron oxides. The impact of these constraints on the competitiveness of the particular process will then be described. Special focus will be put on the evolution of methanogenic conditions in systems formerly characterized by iron and sulfate reducing condition. As methanogenic conditions mostly evolve from micro-niches, methods to study the existence, evolution and stability of such micro-niches will be established. To this end, a combination of Gibbs free energy calculations, isotope fractionation and tracer measurements, and mass balances of metabolic intermediates (small pool sizes) and end products (large pool sizes) will be used. Measurements of these parameters on different scales using microelectrodes (mm scale), micro sampling devices for solutes and gases (cm scale) and mass flow balancing (column/reactor scale) will be compared to characterize unit volumes for organic matter degradation pathways and electron flow. Of particular interest will be the impact of redox active humic substances on the competitiveness of involved terminal electron accepting processes, either acting as electron shuttles or directly providing electron accepting capacity. This will be studied using fluorescence spectroscopy and parallel factor analysis (PARAFAC) of the gained spectra. We expect that the results will provide a basis for improving reactive transport models of anaerobic processes in aquifers and sediments.
Bioavailable nitrogen (N) from anthropogenic sources is an important driver of lacustrine eutrophication. However, N loading in lakes is partially mitigated by microbially mediated processes that take place in redox transition zones (RTZ) within the water column and in sediments. RTZ are also sites of methane (CH4) and nitrous oxide (N2O) production and consumption. As a result of anthropogenic activities, emissions of these greenhouse gases to the atmosphere have significantly increased over the past decades. Lake Lugano is an excellent model system for an anthropogenically impacted lake that represents a hot-spot of quantitative redox-driven transformations involving the green house gases CH4 and N2O, as well as other N species acting as important macro nutrients. Previous studies have revealed that this lake represents an important sink for fixed N and that the anoxic deep-waters and sediments contain high concentrations of CH4. Through the application of stable isotopic, molecular ecological and geochemical techniques, laboratory cultivation and (radio-) tracer studies, the project will try (i) to understand the metabolic pathway involved in N and CH4 elimination in Lake Lugano, (ii) to assess the metabolic rates, at which the respective elimination processes take place, as well as their variability in time and space, (iii) to constrain the isotope effects associated with specific N and CH4 transformations, and (iv) to provide information about the microorganisms involved in these transformations. Thereby, a particularly focus is put on reactions that have essentially been neglected in lacustrine studies thus far, namely the anarobic oxidation of ammonium (anammox) and the anaerobic oxidation of methane (AOM). The project will provide the first comprehensive characterization of early diagenetic reactions in Lake Lugano. Moreover, it may allow insights into novel modes of autotrophic life in lakes. Finally, quantitative estimates of N and CH4 elimination in both the water column and sedimentary RTZ of Lake Lugano will be a prerequisite for ecosystem-scale N and C budgets. Thus, the project will provide important information that is directly pertinent to the health of Lake Lugano in particular, and eutrophied south alpine lakes in general.
Sulfur isotope fractionation (34S/32S) has been used since the late 1940s to study the chemical and biological sulfur cycle. While large isotope fractionations during bacterial sulfate reduction were used successfully to interpret, e.g., accumulation of sulfate in ancient oceans or the evolution of early life, much less is known about fractionation during sulfide oxidation. The fractionation between the two end-members sulfide and sulfate is commonly much smaller and inconsistencies exist whether substrate or product are enriched. These inconsistencies are explained by a lack of knowledge on oxidation pathways and rates as well as intermediate sulfur species, such as elemental sulfur, polysulfides, thiosulfate, sulfite, or metalloid-sulfide complexes (e.g. thioarsenates), potentially acting as 34S sinks.In the proposed project, we will develop a method for sulfur species-selective isotope analysis based on separation by preparative chromatography. Separation of Sn2- and S0 will be achieved after derivatization with methyl triflate on a C18 column, separation of the other sulfur species in an alkaline eluent on an AS16 column. Sulfur in the collected fractions will be extracted directly with activated copper chips (Sn2-, S0), or precipitated as ZnS (S2-) or BaSO4 and analyzed by routine methods as SO2. Results of this species-selective approach will be compared to those from previous techniques of end-member pool determinations and sequential precipitations.The method will be applied to sulfide oxidation profiles at neutral to alkaline hot springs at Yellowstone National Park, USA, where we detected intermediate sulfur species as important species. Determining 34S/32S only in sulfide and sulfate, our previous study has shown different fractionation patterns for two hot spring drainages with sulfide oxidation profiles that seemed similar from a geochemical perspective. The reasons for the different isotopic trends are unclear. In the present project, we will differentiate species-selective abiotic versus biotic fractionation using on-site incubation experiments with the chemolithotrophic sulfur-oxidizing bacteria Thermocrinis ruber as model organism. For selected samples, we will test whether 33S and 36S further elucidate species-selective sulfide oxidation patterns. We expect that lower source sulfide concentrations increase elemental sulfur disproportionation, thus increase redox cycling and isotope fractionation. We also expect that the larger the concentration of intermediate sulfur species, including thioarsenates, the larger the isotope fractionation. Following fractionation in species-selective pools, we will be able to clarify previously reported inconsistencies of 34S enrichment in substrate or product, elucidate sulfide oxidation pathways and rates, and reveal details about sulfur metabolism. Our new methodology and field-based data will be a basis for more consistent studies on sulfide oxidation in the future.
Mercury (Hg) is a persistent micropollutant presenting a substantial risk to the environment and an important threat to the human health. Past and present Hg contaminations of surface waters are thus of major concern due to the potential of Hg to accumulate in biota and magnify in the food chain. Therefore, the improved understanding of the relationship between Hg dispersion, distribution among sediments, particles, colloids and dissolved fractions, as well as accumulation and impact to biota is a prerequisite to fully assess the Hg threat to the aquatic systems and human health. By applying an integrated approach including a combination of field studies, laboratory analyses and numerical simulations, the present proposal aims to assess the impact of the Hg in the industrially impacted surface water bodies in Romania and to identify the possible threat on these resources The project focuses on River Olt basin, as one of the most impacted surface water body in Romania, altered by the cascade dam construction and under extensive past and present industrial activity. The Rm Valcea region comprises a high number of industrial companies including a large chlor-alkali plant (Oltchim), which is recognized as important point sources of Hg. A large array of hydro(geo)logical, physical, chemical, and ecotoxicological tools will be used to address the following key issues: - Performance of Hg survey and estimation the pollution extent in water and sediments; - Determination of the transport and dispersion of Hg in water column and sediments; - Improvement of the understanding on the behaviour of Hg associated to colloids, inorganic particles and organic matter; - Assessment of the bioaccumulation and effect of Hg to different organisms with emphasis on the primary producers in particular microalgae and macrophytes; - Evaluation of the food chain transfer and possible risks for the human health. The project will largely contribute to the understanding of mercury fate and impact in the contaminated systems and improved knowledge on complex processes governing the transfer and impact of Hg from the contaminated surface waters to humans. The project is also expected to contribute broadly to solving societal problems in Romania and to provide a scientific base for a sound definition of the existing problem and understand the causal chain, as well as it will help to develop efficient and cost-effective measures for protection. Strengthening the capacity, improving integration of scientists in the international network as well as developing 'best practices' for impact assessment of pollutants are other major outcomes of the project. They will be a significant step forward contaminant assessment in the entire Danube - Black Sea - Caspian Sea region, as it is a commonly accepted that historical industrial pollution from former communist times represents a significant threat for public health.
Nitrogen isotope ratios can provide important constraints on natural N cycles. In order to use natural abundance stable isotope ratios of dissolved inorganic N species as a means to trace fluxes and transformations of N in aquatic systems, however, it is imperative to understand the isotope effects associated with these specific N transformations. This will also provide information on the transformations themselves. Yet, the possible impact of N2 production processes other than denitrification on global and regional N-isotope budgets has been ignored thus far. Lake Lugano is an excellent model biosystem for an anthropogenically impacted lake. Previous studies have revealed that this lake represents an important sink for fixed N. In addition, they indicate the presence of suboxic consumption of ammonium and, thus, suggest that 'non-traditional' N2 production processes (e.g., anammox) are active in anaerobic portions of the lake. This project addresses the following main research questions: What are the different metabolic pathways of suboxic N2 production in the Lake Lugano water column and in sediments? What are the associated N-isotope effects? What are the respective transformation rates and fluxes? Which microorganisms are responsible for observed N transformations? Combining hydrochemical, microbiological (phylogenetic/molecular genetic analyses, measurements of enzyme activities), with organic-geochemical (anammox lipid analysis) and isotopic techniques (natural abundance of nitrate, ammonium, nitrous oxide isotope ratios, as well as 15N tracer experiments), the project attempts to gain complementary information on specific N transformations and mechanisms of N2 loss in the Lake Lugano water column and sediments, on the microorganisms involved in these transformations, their relevance for the Lake Lugano nitrogen
The simulation models developed in the 1st phase integrate the chemical fate of the veterinary medicines sulfadiazine (SDZ) and difloxacin (DIF) in bulk soil and their subsequent effects on soil microorganisms and on soil functions after single-dose application with manure. In the 2nd project phase, this approach is extended to the rhizosphere, which represents the hotspot of microbial growth in soil and a continuous source of organic compounds released from active roots. The processes of fast and slow sorption, transformation and formation of bound residues of the antibiotics and their main metabolites are adapted to the rhizosphere. The developed effect models for soil functions, structural diversity, and resistance dynamics are extended by relevant plant-soil interactions in close collaboration with the experimental subprojects. The integrated fate-effect model is coupled with a transport model taking heterogeneities of the rhizosphere and plant uptake into account. Processes are parameterized for the two antibiotics SDZ and DIF in rhizosphere and bulk soil with data from the central mesocosm experiment and several planned satellite experiments. The resulting integrated fate-effect models will be evaluated with data from the field experiments. The model is further used to develop indicators such as structural resilience and functional redundancy for antibiotic induced effects, evaluate their applicability for risk assessment and to generate new hypotheses to corroborate the conclusions.
Aerobic granular sludge-based systems have been recently proposed as a promising innovative alternative for wastewater treatment. Aerobic granular sludge may be developed in bubble column-type reactors operated in a sequencing batch mode with anaerobic and aerobic phases. The advantages are relatively low operating and maintenance costs and a high density biomass sludge blanket which results in a compact and efficient treatment system. For a successful operation of this promising treatment system, formation of physically and metabolically stable granular sludge is a prerequisite. A detailed understanding of the granule formation, the bacterial populations involved, and the physical structure is still missing and therefore we investigate three main objectives: (i) the competition and relative importance of PAO and GAO in granular sludge structure, (ii) granule formation and stability for optimized nitrogen and phosphorus removal, and (iii) the microbial assembly and community in relation to granular structure. A combination of process engineering approaches with the molecular characterization of the microbial communities of the granules is applied. The results of the first two project years showed that with propionate as substrate a more stable biological phosphorous removal by PAO could be achieved than with acetate. Microbial community characterization showed that it was indeed dominated by PAO in the propionate reactor whereas GAO were predominant when phosphorous removal was low in the acetate reactor. A new methodology to measure PAO activity in real time inside the reactor based on conductivity measurement was developed and will now be applied to study the competition between PAO and GAO in aerobic granular sludge. Different aeration strategies for improving nitrogen removal were also successfully tested leading to increased biological nitrogen removal. Furthermore, a detailed characterization of granule structure showed that they are composed of multiple micro-granules containing one population and that they resemble rather a cauliflower than an onion with several layers. This increased understanding of the granular sludge formation, activity and structure will allow tailoring aerobic granules with desired physical and metabolic characteristics which is required for a robust implementation and reliable operation of this novel system for the treatment of different kinds of wastewaters from municipalities or industry.
Das Gesamtziel des Verbundprojektes besteht darin, dem nachwachsenden Rohstoff Holz durch einen neuartigen Engineering- Baustoff ein weiteres neues Marktsegment und damit einen erhöhten Absatz zu verschaffen. Im Fordergrund steht die Steigerung der Leistungsfähigkeit von Holzkonstruktionen mit Hilfe von Hochleistungsfasern, beanspruchungsgerechten Textilien sowie verdichteten und geformten Hölzern. Hieraus folgen erhebliche Verbesserungen hölzerner Tragkonstruktionen bezüglich Steifigkeit, Festigkeit, Zähigkeit, Dauerhaftigkeit und Materialeffizienz. rnMittelfristige Ziele sind: (1) Die Einführung von Hochleistungshölzern in die praktische Anwendung für hochbelastete Tragwerkskonstruktionen und (2) Die Etablierung von maßgeschneiderten Holzkonstruktionen im Bereich von Sanierungs- und Neubauvorhaben unter Ausnutzung neuer baustofflicher Eigenschaften, beanspruchungsgerechter Verstärkungen und einer neuen Technologie zur Querschnittsbildung. Besonderen Wert bei der Umsetzung der Projektziele legen die Verbundpartner auf eine stark praxisorientierte Ausrichtung der Arbeiten und die Demonstration der Projektergebnisse im Rahmen geeigneter Pilotvorhaben.rnrnIn Druckversuche an axial beanspruchten Rohrstützen wurde das Last-Verformungs-Verhalten der Leichtbauprofile untersucht. Aufgrund des großen Trägheitsmomentes der Rohrquerschnitte wurden bereits für unverstärkte Profile hohe Trag- bzw. Knicklasten ermittelt. Die Versuche an faserverstärkten Profilen haben jedoch gezeigt, dass deutliche Steigerungen hinsichtlich Traglast und Duktilität der Stützen möglich sind. Zur Vorbemessung und Analyse der Versagensmechanismen wurden Standard-Bemessungsgleichungen bzw. einfache analytische Modelle eingesetzt. Diese wurden anhand der experimentell ermittelten Daten verifiziert.rn
| Organisation | Count |
|---|---|
| Bund | 22 |
| Land | 1 |
| Wissenschaft | 12 |
| Type | Count |
|---|---|
| Förderprogramm | 22 |
| License | Count |
|---|---|
| Offen | 22 |
| Language | Count |
|---|---|
| Deutsch | 6 |
| Englisch | 18 |
| Resource type | Count |
|---|---|
| Keine | 15 |
| Webseite | 7 |
| Topic | Count |
|---|---|
| Boden | 21 |
| Lebewesen und Lebensräume | 22 |
| Luft | 17 |
| Mensch und Umwelt | 22 |
| Wasser | 20 |
| Weitere | 22 |