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.
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.
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.
Is drinking water derived from rivers still clean enough? Almost one third of the groundwater is recharged by river water. River water, sometimes contaminated by waste water, is cleansed through riverbank filtration. The consequences of the changing climate on riverbank filtration are not yet known. Can drinking water quality be enhanced by means of improved wastewater treatment? Background Switzerland's drinking water is mainly derived from groundwater. Approximately 25-30Prozent of the groundwater comes from river water that has filtered through the riverbanks. Frequently, this is the only barrier that divides wastewater-bearing rivers from drinking water systems. Clean drinking water is therefore directly connected with the chemical, physical and biological purification processes occurring in this zone. Do temperature changes and occasional increases in wastewater effluents interfere with the processes within this infiltration zone? River water often contains significant amounts of wastewater effluents from sewage plants. How does river water composition change when wastewater is better treated before it is discharged into rivers? Objectives and methods This project examines climate-induced changes of the infiltration processes of river water into the groundwater. This study will include laboratory experiments as well as field investigations in existing research sites, in order to differentiate between 'normal' and climate-induced changes. The results will build a basis for a numerical model which can then be applied to calculate the processes in typical summer and winter situations, as well as in extreme scenarios. Significance The project will provide results on the behaviour of riverbank filtration under various climatic conditions. On this basis, the existing water supply through riverbank filtrates can then be assessed. Possible upgrades of water supplies or wastewater treatment will be proposed.
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.
Lipophile endokrin wirksame Chemikalien, z.B. synthetische Kontrazeptiva, reichern sich im bei der Abwasserbehandlung entstehenden Klärschlamm an. Wird dieser Klärschlamm als Dünger landwirtschaftlich genutzter Flächen verwendet, besteht die Gefahr, dass die Fremdstoffe aus dem Boden durch Run-off ausgetragen oder von Pflanzen aufgenommen wird. Aufgrund der verschiedenen Aufarbeitungsschritte des Klärschlamms - Stabilisierung, Konditionierung, Entwässerung, Entpathogenisierung - entstehen Klärschlämme, die sich in ihren physikochemischen Eigenschaften (Mineralgehalt, pH, Fein- und Grobstruktur) und in ihrem Gehalt an Kontaminanten unterscheiden können. Bei der Verwendung dieser Schlämme als Dünger können sich die darin enthaltenen Kontaminanten bezüglich ihres Abbau- und Transpoirtverhaltens sowie der Bioverfügbarkeit unterschiedlich verhalten. In diesem Projekt wird das Umweltverhalten ausgewählter Umweltchemikalien in Klärschlämmen in Abhängigkeit von deren Prozessierung und Aufarbeitung untersucht.
Aim of Project The project aims to develop novel methods, which are based on shifts of stable isotope ratios (37Cl/35Cl and 13C/12C), for assessing source and fate of contaminants in the environment. Specifically, the goals are to (i) develop on-line 37Cl/35Cl analytical methods for chlorophenol (CP) congeners, (ii) investigate isotopic fractionation during aerobic and anaerobic biodegradation of CPs, (iii) apply multi-dimensional isotope analysis to identify and quantify their transformation processes at contaminated field sites, and (iv) use radiocarbon analysis to decipher contributions of natural and anthropogenic sources of CPs at contaminated and pristine field sites. Background and Relevance of the Project To assess sites with contaminated soil in industrialized regions such as Europe, methods that allow identifying sources and quantifying biotransformation of pollutants are required. Multi-dimensional compound-specific isotopic analysis is a very promising tool to this end. In the proposed project, this method will be applied to apportion sources and to quantify degradation of CPs at sawmill field sites. CPs belong the group of organochlorines (OCl), which are important man-made contaminants in groundwater and soil ecosystems. Many OCl have shown to be biodegradable, leading to natural attenuation of field sites. However, the identification of this process is not easy. Moreover, many OCl can also have natural sources, complicating the identification of anthropogenic influence on soils. Using compound-specific multi-dimensional chlorine and carbon stable isotopic (37Cl/35Cl and 13C/12C) and radiocarbon (?14C) signatures can overcome these difficulties. Scientific Methodology A GC - ICP - multi collector MS method to measure 37Cl/35Cl isotopic ratios of CPs will be developed. This method will then be used in combination with state-of-the-art 13C/12C methods to perform multi-dimensional CSIA of CPs at former sawmill field sites. Based on isotopic enrichment factors resulting from the accompanying laboratory degradation experiments, the field data will be evaluated, leading to identification and quantification of CP degradation processes. Radiocarbon analysis of CP derivatives near and remote the contaminated field site will give insights about the importance of their natural production.
Im Rahmen dieses Projektes wurde die Situation von Reststoffen aus der Papierindustrie europaweit durch eine umfangreiche Datenaufnahme abgeschätzt. Hierbei zeigte sich, dass in Frankreich und Deutschland die größten Mengen an Papierreststoffen entstehen und die Entsorgungsvarainten am vielfältigsten sind. In den anderen europäischen Ländern fallen wesentlich weniger Reststoffe an, zu meist durch das Fehlen einer Abwasserreinigungsanlage oder durch eine niedrige Altpapiereinsatzquote. Die Reststoffe aus diesen Ländern werden überwiegend auf einer Deponie entsorgt. In einem weiteren Teil des Projektes wurde die stoffliche Verwertung durch Kompostierung von Papierreststoffen auf biochemische und mikrobiologische Parameter hin untersucht. Dabei wurde auch der potenzielle Abbau von chlorierten Phenolen betrachtet. Es zeigte sich, dass die chlorierten Phenole keine große Belastung für Papierreststoffe darstellen. Da im Gegensatz zu den chlorierten Phenolen die Menge an chlorierten organischen Substanzen (AOX) in Papierreststoffen sehr hoch ist, wurde das umweltchemische Verhalten von AOX-Substanzen durch Schüttelversuche in verschiedenen Lösungsmitteln und Lysimeterversuchen getestet. Die Ergebnisse zeigen, dass AOX-Substanzen sich nur in geringem Umfang durch eine Elution mit wässrigen Medien lösen lassen. Da die organischen Schadstoffe (gemessen als AOX) in Papierreststoffen besonders relevant sind, sollte versucht werden, mehr über die chemische Struktur (insbesondere das Molekulargewicht) dieser Substanzen herauszufinden. Dabei wurden die Methoden der Ultrafiltration und der Gelpermeationschromatographie eingesetzt. Die Ergebnisse zeigen eine hohen Anteil AOX-Substanzen im hochmolekularen Bereich, wobei die Struktur der Verbindungen stark vom anfallenden Reststofftyp abhängt. So konnte nachgeweisen werden, dass der Haupteil an AOX-Substanzen in den Deinkingreststoffen überwiegend aus chlorierten Druckfarben, insbesondere den gelben Pigmenten, besteht. Eine Substitution dieser Farbstoffe aus der Azofarbgruppe würde zu einer deutlichen Reduktion der AOX-Problematik führen.
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.
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