Arsenic-contaminated ground- and drinking water is a global environmental problem with about 1-2Prozent of the world's population being affected. The upper drinking water limit for arsenic (10 Micro g/l) recommended by the WHO is often exceeded, even in industrial nations in Europe and the USA. Chronic intake of arsenic causes severe health problems like skin diseases (e.g. blackfoot disease) and cancer. In addition to drinking water, seafood and rice are the main reservoirs for arsenic uptake. Arsenic is oftentimes of geogenic origin and in the environment it is mainly bound to iron(III) minerals. Iron(III)-reducing bacteria are able to dissolve these iron minerals and therefore release the arsenic to the environment. In turn, iron(II)-oxidizing bacteria have the potential to co-precipitate or sorb arsenic during iron(II)- oxidation at neutral pH followed by iron(III) mineral precipitation. This process may reduce arsenic concentrations in the environment drastically, lowering the potential risk for humans dramatically.The main goal of this study therefore is to quantify, identify and isolate anaerobic and aerobic Fe(II)-oxidizing microorganisms in arsenic-containing paddy soil. The co-precipitation and thus removal of arsenic by iron mineral producing bacteria will be determined in batch and microcosm experiments. Finally the influence of rhizosphere redox status on microbial Fe oxidation and arsenic uptake into rice plants will be evaluated in microcosm experiments. The long-term goal of this research is to better understand arsenic-co-precipitation and thus arsenic-immobilization by iron(II)-oxidizing bacteria in rice paddy soil. Potentially these results can lead to an improvement of living conditions in affected countries, e.g. in China or Bangladesh.
Groundwater contamination by organic compounds represents a widespread environmental problem. The heterogeneity of geological formations and the complexity of physical and biogeochemical subsurface processes, often hamper a quantitative characterization of contaminated aquifers. Compound specific stable isotope analysis (CSIA) has emerged as a novel approach to investigate contaminant transformation and to relate contaminant sources to downgradient contamination. This method generally assumes that only (bio)chemical transformations are associated with isotope effects. However, recent studies have revealed isotope fractionation of organic contaminants by physical processes, therefore pointing to the need of further research to determine the influence of both transport and reactive processes on the observed overall isotope fractionation. While the effect of gasphase diffusion on isotope ratios has been studied in detail, possible effects of aqueous phase diffusion and dispersion have received little attention so far.The goals of this study are to quantify carbon (13C/12C) and, for chlorinated compounds, chlorine (37Cl/35Cl) isotope fractionation during diffusive/dispersive transport of organic contaminants in groundwater and to determine its consequences for source allocation and assessment of reactive processes using isotopes. The proposed research is based on the combination of high-resolution experimental studies, both at the laboratory (i.e. zero-, one- and two-dimensional systems) and at the field scales, and solute transport modeling. The project combines the expertise in the field of contaminant transport with the expertise on isotope methods in contaminant hydrogeology.
This follow-up project aims to reconstruct natural (climatic) and anthropogenic-induced hydrological changes and to provide new insights on the anthropogenic pollutants emitted in European environment over the last centuries, by focusing on: (1) The largest freshwater lake of Western Europe (Lake Geneva) and especially on industrial (trace metals) and microbial (pathogenic bacterial activity and resistance to antibiotic) pollution in the Vidy Bay; where are discharges the treated wastewaters of Lausanne since 50 years. (2) A drinking reservoir (Lake Brêt) in order to evaluate the impacts of agricultural activities and sewage emissions on the pollution of drinking water in Switzerland over the last century. Results demonstrate a slight enrichment in anthropogenic heavy metal since the 1950s but an additional (agricultural) source of copper during the last decade. In the absence of industries in the catchment, the records of DDT and PCBs highlight the long-range atmospheric transport of POPs that contaminated rural water resources via catchment runoff. (3) Human impact on the deposition of anthropogenic and natural trace element fluxes were measured in sediment cores from Lake Biel and from two upstream lakes (Lake Brienz and Lake Thun), all three connected by the Aare River. Results indicate that that the construction of sediment-trapping reservoirs significantly decreased regional riverine sediment discharge. Radiometric dating of the sediment core from Lake Biel furthermore identified hydrological releases of anthropogenic radionuclides from the nuclear reactor of Mühleberg located at ca.15 km from Lake Biel. Five publications (in refereed journals) directly resulting from this follow-up proposal are in process of publication.
The proposed project is the follow-up project of our present SNF-project CAPAC (Climate And Pol-lution Analysis of Cairo) phase one. Its main purpose is the finishing of the work begun in phase one in terms of methodology and data analysis. CAPAC is conducted by a doctorand, Miss Corinne Frey. CAPAC aims to combine in situ measurements of the energy balance with remote sensing tech-niques to parameterise urban and non-urban heat fluxes of the mega-city Cairo, Egypt and its surroundings. Cairo is located within a green north-south oriented strip of agricultural land and on the other hand between two desserts in the west and east. This makes the location of Cairo unique and very interesting for an urban climate study like this. Scientific objectives are the computation of very high resolution radiation and heat fluxes in urban areas under the conditions of spatial homogeneity/ heterogeneity of urban land cover. Very interesting is the analysis of how urban greens influence the urban heat fluxes and how the new suburbs of Cairo, which are expanding into the dessert explosively, will modify the local climate. The population of Cairo is growing several hundred thousand people per year. During the first phase of CAPAC a field campaign was conducted in Cairo. This data serve as calibration and validation of the remote sensing analysis. Following this campaign, algorithm development and data analysis will be the main task of the following months. This includes the analysis of the in situ measured flux data, as well as the evaluation of the estimated radiation and energy balance terms using ASTER and LANDSAT remotely sensed data. Main tasks in the determination of the radiation and energy balance terms using satellite data will be (1) the completion of the haze-removal-algorithm for the haze contaminated scenes, (2) the completion of the algorithm for estimation of the aerosol optical depth from satellite data and (3) to improve the S-Sebi method for the estimation of the Bowen-ratio or to find a better suited method for the estimation of heat fluxes. Another task, which is primarily related to quality control is the determination of the Bi-directional reflectance function (BRF) over Cairo using satellite data from CHRIS/PROBA, which are already acquired by the European Space Agency (ESA) on our demand. To substantiate the findings from Cairo another area of interest was chosen, namely Beer Sheva, Israel. Beer Sheva is located in the middle of the desert, offering a pure desert climate. There a small follow-up field campaign is planed together with Dr. Oded Potcher from Ben Gurion University in Beer Sheva.
Objective: The Integrated Project EURANOS, through the commitment of fifty operational emergency management organisations, 'stakeholder groups' and competent RTD institutes of many European countries who actively contribute to the following objectives, will build a fully interactive framework for initiating and promoting practical improvements of emergency management and rehabilitation strategies in Europe never reached before: (A) creating better communication links between those responsible for nuclear and radiological emergency management in European countries with the perspective of fast notifications, information exchange and interaction through more direct channels; (B) providing better coherence and transparency in decision processes on local, national and border crossing interventions as one input to improving public understanding and acceptance of off-site measures; (C) supporting decisions on effective and timely emergency actions and countermeasures in case of nuclear or radiological emergencies by access to reliable, consistent and comprehensive information, and in this way mitigating radiological and economic consequences; (D) developing a coherent framework for the sustainable rehabilitation of living conditions in contaminated areas by implementing integrated and decentralised approaches involving key stakeholders and the public. A common approach and an European perspective of a more harmonised emergency management and rehabilitation strategy on the local, national and supra-national levels will be created and promoted through common emergency exercises and their thorough evaluation together with all stakeholders involved and through 'stakeholder panels' on the key issues of rehabilitation. The common views on improved technical tools; methods, strategies and guidance will also create initiatives on the administrative and political levels to improve the efficacy of European emergency management and rehabilitation strategies.
Although the use of genetically modified plants for bioremediation, or the in situ cleaning of contaminated sites, has been known for quite some time, little attention has so far been paid to the production of antibodies in plants and their ex vivo application in selective depletion. Therefore, highly affine and specific antibodies against algal toxins using microcystin as an example will be produced in plants at low cost within this research project. The basis is a monoclonal antibody (Mab 10E7, species: mouse) generated in a former research project. The sequence of the variable domains will be determined, optimized for plants and sub cloned into suitable plant transformation vectors, which already contain constant antibody sequences. In addition, a scFv fragment containing different tag sequences and fusion proteins will be constructed. Leaf-based (tobacco) as well as seed-based (barley) systems will be used.Affinity-purified plant-produced antibodies (plantibodies) will be characterized in detail for their binding properties using microtitre plate-ELISA and surface plasmon resonance (SPR). The monoclonal mouse antibody will be used as reference. To assure cost-efficiency for future applications, roughly purified fractions (sequential pH and temperature treatment followed by filtration) will be tested for the upscaling. Following immobilization of the plantibody fractions on suitable substrates, for instance membranes, porous polymer monoliths or in porous glasses, their application for depletion will be defined using model water samples spiked fortified with microcystins.
Understanding transport of contaminants is fundamental for the management of groundwater re-sources and the implementation of remedial strategies. In particular, mixing processes in saturated porous media play a pivotal role in determining the fate and transport of chemicals released in the subsurface. In fact, many abiotic and biological reactions in contaminated aquifers are limited by the availability of reaction partners. Under steady-state flow and transport conditions, dissolved reactants come into contact only through transverse mixing. In homogeneous porous media, transverse mixing is determined by diffusion and pore-scale dispersion, while in heterogeneous formations these local mixing processes are enhanced. Recent studies investigated the enhancement of transverse mixing due to the presence of heterogeneities in two-dimensional systems. Here, mixing enhancement can solely be attributed to flow focusing within high-permeability inclusions. In the proposed work, we will investigate mixing processes in three dimensions using high-resolution laboratory bench-scale experiments and advanced modeling techniques. The objective of the proposed research is to quantitatively assess how 3-D heterogeneity and anisotropy of hydraulic conductivity affect mixing processes via (i) flow focusing and de-focusing, (ii) increase of the plume surface, (iii) twisting and intertwining of streamlines and (iv) compound-specific diffusive/dispersive properties of the solute species undergoing transport. The results of the experimental and modeling investigation will allow us to identify effective large-scale parameters useful for a correct description of conservative and reactive mixing at field scales allowing to explain discrepancies between field observations, bench-scale experiments and current stochastic theory.
Arsenic-contaminated ground- and drinking water is a global environmental problem with about 1-2Prozent of the worlds population being affected. The upper drinking water limit for arsenic (10 ìg/L) is often exceeded, especially in Asian countries, such as Vietnam. Household sand filters are already used as one very simple and cost-efficient treatment to remove arsenic from water. Oxidation of dissolved iron (Fe(II)) present in the groundwater leads to the formation of sparsely soluble iron(hydr)oxide particles (Fe(III)OOH) in the sand filter, which bind negatively charged arsenic species and reduce arsenic concentrations in the water. Arsenite (As(III); H3AsO3) binds generally less strong to metal oxides than arsenate (As(V); H2AsO4 -/HAsO4 2-), therefore As(V) is removed much more effectively than As(III). This is why As(III) oxidation to As(V) is of special interest for arsenic removal from drinking water. Whether and how the activity of iron- and arsenite-oxidizing bacteria contributes to effective arsenic removal in household sand filters is currently not known. One of the goals of this study therefore is to isolate, identify, and quantify Fe(II)- and As(III)-oxidizing microorganisms from filters and to study their iron and arsenic redox activities. Cultivation-based work will be complemented by molecular, cultivation-independent techniques to characterize and quantify the microbial communities in samples from different filter locations taken at various time points during filter operation (both at field sites and in artificial laboratory filter systems). The isolated iron- and arsenite-oxidizing bacteria will be studied with respect to their abilities to precipitate iron minerals (in the presence or absence of arsenic) and oxidize arsenite. Biogenic and abiogenic iron minerals formed by the isolated strains in the lab, on the sand filter material in Vietnam and in artificial laboratory filter systems will be identified and characterized, also with respect to arsenic sorption. And we will determine how biotic and abiotic processes that contribute to arsenic mobilization from arsenic-loaded iron mineral phases affect filter performance over time. The long-term goal of this research is to better understand the microbial redox transformation processes that drive arsenic/iron mineral interactions in natural and engineered systems, such as household sand filters and to give recommendations for improved filter use and filter material disposal.
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.
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