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.
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.
Background: Low Emission Zones (LEZs) are areas or roads where the most polluting vehicles are restricted from entering. The effectiveness of LEZs to lower ambient exposures is under debate. This study focused on LEZs that restricted cars of Euro 1 standard without appropriate retrofitting systems from entering and estimated LEZ effects on NO2, NO, and NOx (=NO2+NO) concentrations. Methods: Continuous half-hour and diffuse sampler 4-week average NO2, NO, and NOx concentrations measured inside and outside LEZs in 17 German cities of 6 federal states (2005-2009) were analysed as matched quadruplets (two pairs of simultaneously measured index values inside LEZ and reference values outside LEZ, one pair measured before and one after introducing LEZs with time differences that equal multiples of 364 days) by multiple linear and log-linear fixed-effects regression modelling (covariables: e.g., wind velocity, amount of precipitation, height of inversion base, school holidays, truck-free periods). Additionally, the continuous half-hour data was collapsed into 4-week averages and pooled with the diffuse sampler data to perform joint analysis. Results: More than 3,000,000 quadruplets of continuous measurements (half-hour averages) were identified at 38 index and 45 reference stations. Pooling with diffuse sampler data from 15 index and 10 reference stations lead to more than 4,000 quadruplets for joint analyses of 4-week averages. Mean LEZ effects on NO2, NO, and NOx concentrations (reductions) were estimated to be at most - 2 microgram/m3 (or - 4 percent). The 4-week averages of NO2 concentrations at index stations after LEZ introduction were 55 microgram/m3 (median and mean values) or 82 microgram/m3 (95th percentile). Conclusion: This is the first study investigating comprehensively the effectiveness of LEZs to reduce NO2, NO, and NOx concentrations controlling for most relevant potential confounders. Our analyses indicate that there is a significant, but rather small reduction of NO2, NO, and NOx concentrations associated with LEZs. Key words: air quality, low emission zone, NO2, NO and NOx, air pollution
Objective: Space heating accounts for more than 50Prozent of the energy consumption of public & residential buildings, and reduction of this energy demand is a key strategy in the move to low energy/low carbon buildings. The careful management of air flow within a building forms part of this strategy through the control of inlet fresh air and exhaust air, maximising air re-circulation, and minimising the amount of fresh air which is often drawn in through a heat exchanger. However, there is a high risk that the air quality is reduced. Continued exposure to environments with poor air quality is a major public health concern in developed and developing countries. It is estimated that the pollutants responsible for poor air quality cause nearly 2.5 million premature deaths per year world-wide. Significantly, around 1.5 million of these deaths are due to polluted indoor air, and it is suggested that poor indoor air quality may pose a significant health risk to more than half of the world's population. Perhaps surprisingly, remedial action to improve air quality is often easy to implement. Relatively simple measures such as increased air flow through ventilation systems, or a greater proportion of fresh air to re-circulating air are sufficient to improve air quality. Low-energy air purification and detoxification technologies are available which will reduce the concentration of specific pollutants. Similarly, filtration systems (e.g. electrostatic filters) can be switched in to reduce the level of the particulate matter in the air (the principle pollutant responsible for poor health). The INTASENSE concept is to integrate a number of micro- and nano-sensing technologies onto a common detection platform with shared air-handling and pre-conditioning infrastructure to produce a low-cost miniaturised system that can comprehensively measure air quality, and identify the nature and form of pollutants. INTASENSE is a 3-year project which brings together 8 organisations from 5 countries.
Antimony (Sb) is a rather rare element in the earth's crust, but in the recent past, human activities have led to highly elevated Sb concentrations in soils and sediments at many locations and, as a consequence, to increased exposure of biota to this toxic element. Soil contamination by Sb has recently become an urgent issue in particular on shooting ranges. In Switzerland, all shooting ranges are currently examined and will be remediated within the next decade. This implies the removal of large quantities of contaminated soil. Large fractions of these soils are not heavily contaminated but have to be treated because they are located in pollution-sensitive areas such as groundwater protection zones. This soil can potentially be reused for less sensitive types of land-use, saving high treatment costs and precious hazardous waste disposal space. Knowledge about the risks of Sb leaching from such soils is very limited, however. One key factor regarding solute leaching is the water regime, particularly in soils subject to permanent or periodic water-logging. Water-logging strongly inhibits soil aeration, and this can have a strong influence on the entirety of chemical and biological conditions affecting solute transport in soil. This holds all the more for elements that are sensitive to changes in their oxidation state under environmental conditions such as Sb. Given that there is very little information available on the transport behavior of Sb in soils, particularly under dynamic water regimes, this project has the aim to investigate the influence of water-logging on Sb leaching from contaminated soil. For this purpose, we carry out experiments with a relocated shooting range soil as well as with a comparable synthetic soil in order to identify and model the role of sorption and redox processes on Sb mobilization and leaching. Special attention will be given to the speciation of Sb in the soil solution. The results will be relevant beyond providing a scientific basis for the risk assessment of Sb leaching from contaminated soil, as it will also further the mechanistic understanding of how water-logging affects the transport of redox-sensitive solutes in soils in general.
Selenium is a double edged chemical element, since it is both essential yet highly toxic. Besides its high acute toxicity, selenium is characterized to be strongly bioconcentrated from dissolved selenium species (selenite, selenate, selenoaminoacids) in aquatic primary producers and further biomagnified during food chain transfer. In consequence, water borne selenium concentrations of as little as 2 myg / L have been documented to cause severely adverse effects on top predators such as water birds and fish. Although the ecotoxic impact was first noticed in the early 1980s, to date no definitive solution has been found to remediate selenium contaminated drainage and waste waters. Due to the water insolubility of elemental selenium, the dogma that 'elemental selenium is not bioavailable and not toxic' dominates current scientific literature and forms the basis for various remediation approaches using microorganisms to convert selenium oxyanions to elemental selenium. However, a number of considerations and recent studies suggest that the dogma might only be true for 'bulk' elemental selenium, yet not for microbially formed, so called biogenic selenium. Biogenic differs from bulk elemental selenium considerably regarding its physico-chemical properties. Biogenic elemental selenium consists of nanometer sized spheres, which do not crystallize to larger particles of trigonal elemental selenium, the thermodynamically stable allotrope. The latter is due to stabilization by proteins associated with the particles. As a consequence, biogenic elemental selenium does not settle yet remains in waters as a colloidal suspension, thus being subject to uptake by biota. Although the general bioavailability of biogenic elemental selenium has been proven, it has not been studied in detail, in particular not in aquatic environments. We aim at quantifying acute and chronic toxicity in the model organism Daphnia magna, elucidating the underlying mechanism of toxicity. Furthermore, we will quantify biogenic elemental selenium uptake, depuration and biotransformation to proteinous forms (the species most relevant for trophic transfer). Thus we will be able to deliver an improved model of selenium food chain transfer in aquatic environments, the basis for appropriate selenium risk assessment. During the course of the proposed research, such questions as the following will be answered: - Is biogenic elemental selenium bioavailable and / or toxic to Daphnia magna? Which are the mechanisms underlying toxicity? - To which extent is biogenic selenium biotransformed to proteinous (highly bioaccumulative) species? Does biogenic elemental selenium represent a significant entrance port for selenium at base of aquatic food chain?
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.
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