Das Projekt "Release of hexavalent chromium from ore processing residues and the potential of biochar for chromium immobilization in polluted soils" wird vom Umweltbundesamt gefördert und von Universität Köln, Fachgruppe Geowissenschaften, Geographisches Institut durchgeführt. 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.
Das Projekt "Redox processes along gradients" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Lehrstuhl für Hydrologie, Limnologische Forschungsstation durchgeführt. 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.
Das Projekt "Transport of EINP through soil affected by the dynamics of infiltration flux and particle properties" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Department Bodenphysik durchgeführt. 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.
Das Projekt "The role of intermediate sulfur species (ISS) for isotopic fractionation processes during abiotic and chemolithoautotrophic sulfide oxidation in a natural environment" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Department Catchment Hydrology durchgeführt. 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.
Das Projekt "Climate-Biogeochemistry Interactions in the Tropical Ocean - A8: Transport and fluxes across the bottom boundary layer" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt. The major goal of this new subproject is to estimate transport and fluxes of solutes between the bottom boundary layer, the stratified interior ocean and the ocean mixed layer on the continental slope and shelf regions of the Peruvian and Mauritanian Oxygen Minimum Zones (OMZ). The objectives will be achieved by estimating diapycnal and advective fluxes using two different methodological approaches: The first is basedon the measurement of the radium isotope distribution in sediments and in the water column. The second approach will use a combination of oceanographic measuring systems for the determination of turbulences, currents and hydrography. Subproject A8 will contribute to the understanding of the solute budget of the OMZ's and establishes a link between the benthic and pelagic research foci within the SFB 754.
Das Projekt "The chronological and spatial distribution pattern of plankton in lakes: Abiotic disorders and organic interactions with a special focus on Planktothrix rubescens" wird vom Umweltbundesamt gefördert und von Universität Konstanz, Limnologisches Institut durchgeführt. The aim of the project is to investigate the role of physical forcing, resource availability, and organismic interactions for the spatial and temporal distribution patterns of plankton in lakes. The research is focused on the distribution patterns of the buoyant cyano bacterium Planklothrix rubescens in Lake Ammer and compares the abundance of P. rubescens with the temporal and spatial variability of abiotic conditions and of phyto- and zooplankton. The main hypotheses are that (1) transport by internal wave motions has a substantial influence on the horizontal distribution patterns of P. rubescens and also affects the distribution of other phyto- and zooplankton; (2) vertical water column motions associated with internal waves cause fluctuations in the vertical layering of P. rubescens and thus alters its competitive abilities; (3) horizontal differences in habitat conditions, i.e. limited vertical water column depth in bays and resource gradients near river inflows, result in longer-term characteristic horizontal distribution patterns of P. rubescens and other plankton; (4) layers of toxic P. rubescens may interfere with the vertical migration of zooplankton. These research questions will be addressed in extensive field experiments measuring horizontal and vertical distribution patterns of plankton and abiotic conditions at temporal scales ranging from minutes to several weeks. In-situ measuring techniques for plankton and abiotic parameters, providing sufficient teniporal and spatial resolution, will be combined with water sample analyses to support them. The distribution of P. rubescens will be measured by using our newly developed in-situ technique that combines information from optic and acoustic instruments. The field experiments will be complemented with 3D and 1D model approaches. The intension of the modeling work is to support the interpretation of the field data by performing numerical experiments that investigate the response of horizontal distribution patterns of P. rubescens to physical forcing, patchy nutrient distribution (e.g. river inflow) or the presence of a shallow bay and by studying the implications of water column depth, internal wave induced fluctuations in light intensity, and grazing for the layering of p. rubescens in a vertical water column.
Das Projekt "Mercury threat in industrially impacted surface water bodies in Romania - integrated approach (MERCURO)" wird vom Umweltbundesamt gefördert und von Universite de Geneve, Institut F.-A. Forel durchgeführt. 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.
Das Projekt "Nitrogen elimination pathways and associated isotope effects in Swiss eutrophic Lake Lugano" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule Zürich, Institut für Integrative Biologie durchgeführt. 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
Das Projekt "Bioactive natural products - linking chemical and biological information for lead discovery, preliminary SAR and assessment of undesired pharmacological properties" wird vom Umweltbundesamt gefördert und von Universität Basel, Department Pharmazeutische Biologie durchgeführt. Small molecule natural products are a prolific source of inspiration for the development of new drugs, and essential tools in basic biomedical research as probes of biological functions. The contribution of academic laboratories in natural products discovery has been essential. The limiting factor of traditional approaches in bioactivity-directed natural product research has been the tedious process of purification and identification of active molecules from a highly complex extract matrix. Recent technological advances enable substantial improvements in efficiency via a consequential miniaturization of the screening and discovery process, and automation of certain process steps. The aim of the project is to discover small molecule natural products leads from plants and fungi acting against clinically relevant and/or emerging targets in important disease areas. The targets have been selected on the basis of specific criteria, such as (i) novelty and importance of target; (ii) lack of specific/selective inhibitors; (iii) need for enhancement of structural diversity of ligands; (iv) difficulty/impossibility to use rational drug discovery approaches; (v) access to animal models. Indications include CNS (selective GABA-A receptor agonists), inflammation and cancer (modulation of angiogenesis and lymphangiogenesis, inhibition of PI3 kinases). In addition, a screening for hERG channel inhibition will be carried out as the currently most critical anti-target in drug discovery & development. An extract library and a technology platform for the miniaturized discovery of natural products will be used. The library consists of currently 1000 plant and fungal extracts. An ethnomedicine-based focussed sub-library will be specifically tested for GABAA receptor agonistic properties. All process steps in the screening and consecutive lead identification are miniaturized, in part automated, and based on the 96-well microtiter footprint. Most of the assays are via external collaborations, and some assays involving cell signalling are established in-house. Prioritized extracts are submitted to HPLC-based activity profiling with microtiter-based fractionation of column effluent, and simultaneous on-line spectroscopic (PDA, ion-trap ESI and APCI-MS, and ESI-TOF) analysis. Compound dereplication and identification is supported by off-line microprobe NMR spectroscopy. Around the active target molecules, structurally related compounds will be characterized to generate small 'virtual' libraries for preliminary structure activity relationships. Calculation of physico-chemical data and secondary bioassays will characterize leads, and shortlisted compounds will be tested in vivo for proof of concept. For this purpose, compounds of interest are isolated in a targeted manner in amounts of up to several hundred mg.
Das Projekt "Mikrobieller Metabolismus von Modellpestiziden in der Drilosphäre und Einfluss auf die N2O-Bildung: Verknüpfung von Prozessen mit Populationen" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Biologie, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Ökologische Mikrobiologie durchgeführt. Der Einsatz von Pestiziden ist in der Landwirtschaft weit verbreitet. Mineralisierung von Pestiziden findet im Boden hauptsächlich durch aerobe mikrobielle Prozesse statt. Bereiche hoher mikrobieller Aktivität im Boden schließen die Drilosphäre mit ein, d.h. Gänge, Darminhalt und Kot von Regenwürmern. Das Treibhausgas Distickstoffmonoxid (N20) wird in der Drilosphäre durch die dort ablaufenden Nitrifikation und Denitrifikation gebildet, welche von Pestiziden beeinflußt werden können. Allerdings sind die physikalisch-chemischen Parameter, aerobe und anaerobe Pestizid Abbauwege, sowie die Pestizid-abbauenden Mikroorganismen in der Drilosphäre nur wenig untersucht. Der Einfluß von Pestiziden und deren Abbauprodukte auf die Nitrifikation und Denitrifikation in der Drilosphäre sind größtenteils unbekannt. Daher sollen die folgenden Hypothesen mit Hilfe von Regenwürmer-enthaltenden Bodensäulen getestet werden: (i) In der Drilosphäre kommen bislang unbekannte, hoch aktive Prokaryotcn vor, die Phenoxyessigsäure Herbizide und deren Abbauprodukte umsetzen; und (ii) Phenoxyessigsäure-Herbizide und deren Abbauprodukte inhibieren die N20-Bildung und das Wachstum von bislang unbekannten Nitrifikanten und Denitrifikanten in der Drilosphäre. Zwischen- und Abbauprodukte sollen mit Hilfe von Gaschrornatographie (GC) und Hochdruckflüssigkeitschromatographie- Massenspektrometrie (H PLC-MS) bestimmt werden. 16S rRNA und mRNA basiertes 'Stable Isotope Probing', Quantifizierung funktioneller Gene mittels quantitativer 'real time' PCR (qPCR), 'Most Probable Number' (MPN) Analysen und zielgerichtete Isolierungsmethoden sollen zur Identifikation und Charakterisierung der prozeß-assoziierten, mikrobiellen Populationen und Mikroorganismen eingesetzt werden
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