Offene Themen für Bachelorarbeiten
| Analyze PVC nanoplastics in soils |
The analysis of individual nanoplastic particles (<1000nm) is still very difficult because it is very hard to generate spectroscopic data of these tiny particles. The aim of the thesis is to test scanning transmission electron microscopy (SEM) for the analysis. With SEM and an special (EDX) detector it is possible to analyze the elemental composition of a particles. While this might not be enough to differentiate most plastics from natural organic particles, it might be possible to differentiate PVC partciles (because of the special C/Cl ratio). This idea will be tested in cooperation with the Environmental Mineralogy Group. First PVC nanoplastic will be produced in the lab and the methods will be tested. If the identification works, soil samples with assumed high PVC concentrations (e.g. close to a factory) will be sampled, nanoplastics will be extracted and analyzed by SEM/EDX. Please contact Prof. Dr. Moritz Bigalke |
| Plastics in viticulture: input pathways for microplastics to the environment under different vineyard management practices |
Plastic materials are widely used within agricultural practice, causing direct contributions to environmental plastic pollution. Special cultures like vineyards have so far received little attention in plastic research. However, several observations indicate a wide use of plastics in viticulture or the input through mulching materials. Based on literature research, field observations and interviews with viticulturists, possible plastic input pathways into the vineyard should be identified and traced. The aim of the work is to establish a causal chain of the input pathways and to quantify them in comparison between conventional cultivation and biodynamic cultivation practice. Please contact Dr. Collin J. Weber |
| Identification of single flood events within floodplain soils |
Floodplain soils are important geoarchives to access past environmental changes and fluvial system dynamics. Within undisturbed floodplain soils of large rivers, the interpretation of “flood beds” poses the change of a simple and inexpensive method to date those soils and trace the sediment accumulation within the last 100 years. Based on field sampling at the Rhine floodplain (Nature reserve Kühkopf, Hesse) and stratigraphic documentation of the sediment cores a first flood bed interpretation should be established through data correlation to flood data of the upper Rhine. First interpretations will be validated through the analysis of sediments grain size composition, organic matter and total organic carbon contents as well as trace metal (Zn, Cu, Pb) analysis via ICP-MS. The aim of the work is the validation of the field-based flood bed interpretation and relative sediment dating by characterising individual flood beds in relation to changing trace metal depositions over time. Please contact Dr. Collin J. Weber |
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Investigation of the fatty acid profile of different edible oil products |
Different vegetable oil samples may have different fatty acid profiles. The fatty acid profile can be a key to determine the origin of biodiesel, which is made from fatty acids of vegetable oil. You are expected to 1) search fatty acid profiles of different edible oils samples in the literature, 2) investigate methods to analyze fatty acid profile, 3) determine fatty acid profile of different edible oil products, 4) discuss the outcome. Please contact Prof. Dr. Moritz Bigalkeand Dr, Kaori Sakaguchi-Söder |
| Soils in environmental education – underestimated possibilities and the development of an educational concept for soil topics |
Soils receive a poor public recognition and attention in contrast to other environmental systems (e.g., oceans). The lack of characteristics like “cuteness” or “beauty” as well as the limited visibility of soils or the emotional connotation to “dirt”, are some reasons for this circumstance. Overall, soils and soil related environmental topics (e.g., soil health, soil degradation) are insufficient considered within environmental education. Several soil profiles in the near surrounding of Darmstadt and in cooperation with the environmental education group of the Hofgut Oberfeld (Lernort Bauernhof), offer the possibility to develop an educational concept for teaching about soil formation, the role of soils in the environment and their importance for humans, as well as soil protection. Based on the available soil profiles, their characterisation and basic soil data a concept should be developed with enables an easy access to soil information for children, young people and adults. The aim of this work is the preparation and presentation of soil data for teaching content in environmental education as well as the creation of an integrated concept for communication. Please contact Prof. Dr. Moritz Bigalke |
| Bodenlehrpfad Darmstadt |
Based on the previous BSc topic about didactic presentation of the soil on the Oberfeld and in the nearby forest, the information can be brought together with the spatial geology information and information about historical and current land use practice to fully understand the soil development. The information can be used to develop a didactic concept about how to connect the different profiles and maybe integrate geomorphology features or rock outcrops to a Bodenlehrpfad (Soil-learning path) with enables an integrated understanding of the soil development in the area. Please contact Prof. Dr. Moritz Bigalke |
Offene Themen für Masterarbeiten
| Micro- and nanoplastic related topics | |
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Microplastic deposition in middle and high mountains Start from March 2024 |
Microplastics are transported through the atmosphere worldwide and can be deposited anywhere and at any time. However, measuring the atmospheric background and deposition is associated with various analytical difficulties. In particular, the contamination of samples during sampling and analysis must be kept to a minimum and strictly controlled. The aim of this work is the quantification and analysis of microplastics from snow samples collected in February 2024 in a low mountain range in Germany and in June 2024 on a glacier in the Eastern Alps. Microplastic extraction and analysis using µFTIR and, if necessary, SEM after consultation, should provide initial corrected data on atmospheric background deposition but also show the comparison to anthropogenic inputs from winter and mountain sports. Please contact Dr. Collin J. Weber |
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Microplastic transport in organic forest soil horizons Start from September 2023 |
In contrast to other soil systems worldwide, there is no data on microplastic abundance in forest soils so far and therefore less knowledge about transport processes of microplastic in forest soils. One major difference between forest and non-forest soils, is the coverage of mineral soil horizons with organic layers (O-layers) build up from litter in different decomposition states. Within those organic horizons, microplastics could be transported downwards to the mineral soil by i) leachate (water-transport) or by ii) the progressing decomposition of fresh litter. The aim of this work will be the set-up and conduction of a laboratory experimental trail using different self-produced microplastics and combinations of forest organic horizons. The experimental trail should be designed in a way, that both possible transport processes can be studied. Furthermore, microplastic extraction and analysis via µFTIR will be necessary to quantify microplastic transport rates over depth and time. Please contact Dr. Collin J. Weber |
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Spatio-temporal monitoring of microplastics in forest soils Start from September 2023 |
In contrast to other soil systems worldwide, there is no data on microplastic abundance in forest soils so far. However, forests cover large areas of the globe and their soils fulfil important ecosystem functions. Therefore, monitoring of microplastic pollution within forest soil becomes important to understand the input pathways and effects of microplastics in forests. In cooperation with the Federal State Agency (HLNUG) of Hesse, we can access soil samples from different forests across the federal state, which have been sampled as part of the permanent soil monitoring program since the late 1990s. This soil samples will be used to extract and analyse microplastics following a laboratory extraction protocol and µFTIR analysis. Microplastic concentrations, particle size differentiations and polymeric composition will be used to describe the microplastic contents in forest soils within the last 20 years. As several soil related datasets (e.g., basic soil data, organic pollutants, trace metals) are already available, intensive statistical analysis could be additionally performed to access potential interactions between plastics and other pollutants in forest soils. The aim of this work will be the spatio-temporal monitoring of microplastics in forest soils on a federal state level and the access to first information on microplastic pollution characteristics in forest systems. Please contact Dr. Collin J. Weber |
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The uptake of small microplastics and nanoplastics by plants Start from October 2023 |
Small microplastics (< ca 10 µm) and nanoplastics (< 1 µm) can be taken up from soils into plants. The uptake can take place at the root surface and is dependent on the soil and plastic properties. The uptake of the plastics can probably affect plant health. If crops are considered the plant uptake of microplastics is a possible way in the human food chain. In this master thesis crops will be grown in soils, which are conditioned with plastics of a defined size, which contain a flourescent label. The size of the particles or the soil type can be varied to assess the effect of these factors on plastic uptake. Soil solution samples will be taken at different times during plant growth and analyzed for plastics to assess plastic availability for plants. The crops will be grown to full maturity and then be harvested. The different plant parts will be analyzed for the presence of plastics in their tissues and the results will be interpreted in terms of uptake and translocation of plastics in crops Please contact Prof. Dr. Moritz Bigalkeand Hannah Forsyth |
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Microplastic in agricultural soils Start from September 2023 |
Agricultural soils are important for the human nutrition but also receive high loads of microplastics. We have a full set of soils with different history of plastic application reaching from mulch foil, to compost and sewage sludge application. The soils can be analysed for its microplastic concentrations and characteristics to understand if different sources cause different MP patterns in agriculture. Please contact Prof. Dr. Moritz Bigalke |
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Investigation of polymer samples by Py-GC/MS Start from October 2023 |
Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) is one of the techniques to quantify micro and nano plastics (MNPs) and tire wear particles (TWPs) in environmental samples. In the graduation project, you are expected to 1) search methods to analyze major polymers by Py-GC/MS, 2) implement methods (incl. sample preparation) using our new Py-GC/MS, 3) optimize the methods for a better precision and 4) discuss the outcome. Please contact Prof. Dr. Moritz Bigalke and Dr. Kaori Sakaguchi-Söder |
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Investigation of hazardous organic compounds in tire wear particles Start from January 2024 |
Tire wear particles (TWPs) are known to contain a wide range of hazardous organic compounds, including polycyclic aromatic hydrocarbons (PAHs), vulcanization additives and antioxidants. Roadside fields or diches that are contaminated with TWPs may also be contaminated with these hazardous organic compounds. In the graduation project, you are expected to 1) search literature to investigate the nature and extent of hazardous organic compounds in TWPs, 2) investigate GC/MS methods to analyze hazardous organic compounds, 2) determine the concentration of selected hazardous compounds in TWPs and 4) discuss the outcome. Please contact Prof. Dr. Moritz Bigalke and Dr. Kaori Sakaguchi-Söder |
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Investigation of PAH contamination of tire wear particles Start from May 2023 |
Polycyclic aromatic hydrocarbons (PAHs) are major contaminants in urban run-off. Tire wear particles (TWPs) collected along roadside soil may also contaminated with PAHs. TWPs with PAHs may cause adverse effects on environment. Further, PAHs on the surface of TWPs may have certain influence when analyzing them in pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). In the graduation project, you are expected to 1) search literature to investigate the nature and extent of the PAHs in and on the TWPs, 2) search methods to analyze polymers by Py-GC/MS, 2) artificially contaminate particles made from a commercial tire with a typical PAH with different amounts, 3) analyze the tire particles contaminated with the PAH and evaluate the influence of PAHs on the Py-GC/MS analysis and 4) discuss the outcome. Please contact Prof. Dr. Moritz Bigalke and Dr. Kaori Sakaguchi-Söder |
| Trace metal and metal isotpoes related topics | |
| Metal contamination of (flood)plain soils in Biebergemünd |
Arsenic (As) is a highly toxic metalloid of global concern. Mining for several centuries has led to a severe As and lead (Pb) pollution in soils of Bieber and Rossbach in Biebergemünd, Southeast Hesse. Rainfall and flooding events caused the mobilization of heavy metals from the soils and led to a deposition in floodplain soils further downstream of the Bieber posing environmental risks. Current soil investigations and risks assessment studies are carried out by the HIM-ASG and the engineering office GEONIK GmbH. The master student will aid in the risk assessment of contaminated soils. In this project, (flood)plain soils will be analyzed for heavy metal contents to assess the degree and distribution of contamination. Furthermore, (flood)plain from different land use will be used for flooding experiments to study the potential mobility of heavy metals during changing redox conditions. A sequential extraction (SE) procedure will be carried out to the assess changes in metal partitioning in the soil solid phase. Please contact Dr. Kai Nitzsche |
| Mobility of arsenic and heavy metals in floodplain soils of the Usa River |
Arsenic (As) is a highly toxic metalloid of global concern. Often, As originates from natural sources such As-bearing iron oxides or As-bearing sulphide minerals in geothermal deposits. Reduction of iron oxides under anoxic conditions and oxidation of sulphide minerals leads to the mobilization of As into groundwater and/or deposition in (flood)plain soils. Changes in redox conditions driven by wet-dry events may mobilize As from such floodplain soils. The city Bad Nauheim is located in a fault zone on the eastern edge of the Taunus. Here, As-bearing hydrothermal alterations are the source of As in (flood)plain soils. Furthermore, untreated wastewaters from thermal water production have contributed to the pollution of floodplain soils by As and other heavy metals such as zinc (Zn). In the first step, As-contaminated floodplain soils will be identified in a field campaign following elemental analysis. Next. flooding experiments will be carried out with As-contaminated floodplain soils of different land use to study the potential mobility of As under changing redox conditions. A sequential extraction (SE) procedure will be carried out to the assess changes in metal partitioning in the soil solid phase. Overall, we expect to gain a better knowledge of the potential mobility of As from floodplain soils due to expected extreme weather conditions that cause flooding and drying. Please contact Dr. Kai Nitzsche |
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Uranium mobilization from alluvial deposits by nitrate Start from September 2023 |
Uranium (U) contamination of groundwater has received recent attention. Uranium is considered both a geogenic and anthropogenic contaminant. In the environment, U occurs as insoluble U reduced (IV) in minerals or as soluble U(VI) species under circumneutral oxidising conditions. Alkalinity and carbonate concentrations favour the U mobility by forming U(VI)-carbonato and ternary U(VI)-Ca-carbonato complexes. Recently, nitrate was suspected to mobilize naturally occurring U from minerals by stimulating the microbial community and catalysing the oxidization of U(IV). Due to the excessive use of organic manure and mineral fertilizers, nitrate contamination of groundwater is highly problematic in Germany and many other countries thus posing the risk of U mobilization. A high-resolution monitoring station at an agricultural side in the Hessian Ried has detected U concentrations that often exceed the allowed threshold (10 µg L-1). Denitrification was suspected to trigger the U roll front. Yet, further information on the sources and mobility of U are necessary. In this study, the student will incubate reduced and oxidized sediments from the groundwater monitoring site using different concentrations of bicarbonate, nitrate, and mixtures between these two. Additionally, control samples will be treated with sodium azide to inhibit microbial nitrate respiration. The student will analyze U and other trace metal concentrations in the dissolved phase and in the colloidal phase, and in sequential extractions after different sampling times. A specific focus is given on the metalloid arsenic (As), which is strongly redox sensitive, i.e. As concentrations were often beyond the allowed threshold (10 µg L-1) in the reduced zone of the aquifer. Based on the results, we expect a better understanding of the mechanisms that lead to U contamination of groundwater in the Hessian Ried which has implications for other sites characterized by U and nitrate contamination. The thesis will be a cooperation between the Hydrogeology and Soil Mineralogy and Soil Chemistry groups and co-supervised by Dr. Stephan Schulz and Ph.D. Kai Nitzsche. Please contact Dr. Kai Nitzsche |
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Cu and Zn isotope measurements of agricultural applications |
Over the last decades, Cu and Zn stable isotopes have become popular tools for tracing anthropogenic Cu and Zn sources in different environmental systems. Agricultural applications such as pesticides, inorganic fertilizers, lime, sewage sludge, and organic manure are major Cu and Zn sources to agricultural soils. Today, few data on Cu and Zn stable isotopes exist for such agricultural applications. To better constrain the use of Cu and Zn stable isotopes as anthropogenic tracer in agricultural soils, a wide inventory of Cu and Zn stable isotope ratios of agricultural applications is required. In this study, Cu and Zn stable isotope ratios of typical agricultural applications (pesticides, inorganic fertilizers, lime, sewage sludge, and organic manure including slurry, composts, digestate (Gärrest), biochar will be determined. Please contact Dr. Kai Nitzsche |
| Leaching and sorption of trace metals from and on microplastics |
Trace metals as inorganic pollutants, but also micronutrients, and microplastics as polymeric particulate pollutants are both present within soils. Therefore, interactions of both substances are conceivable depending on biogeochemical soil properties. For example, trace metals from the soil matrix could adsorb to plastic particles. However, it is also known that metals and metal compounds are present in plastics (e.g., colour pigments), which could be leached from the plastics in the soil. Those processes have been already studied within marine or aquatic systems, but not for soil systems so far. The aim of this work will be the implementation and conduction of both, leaching and sorption experiments under laboratory conditions with common polymers (PE, PP, PS) and trace metals like copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd). The focus should be on leaching and sorption within soil pore water containing different amounts of polymers and trace metals as well as different water conditions (e.g., pH, carbonate content and dissolved organic carbon). Please contact Dr. Collin J. Weber and Dr. Kai Nitzsche |
| Special topics | |
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Investigation of hydrogen isotope ratios of rapeseed samples Start from January 2024 |
Rapeseed oil is one of the major feedstock materials to produce biodiesel. In Germany, rapeseeds are cultivated in the fields of a wide range of soil types. Depending on the soil types, behaviors (e.g.: evaporation) of the water in the soil may differ. As a result, hydrogen isotope ratios of the soil water may differ. When plants take up soil water with different hydrogen isotope ratios, the isotope fingerprint of rapeseed oil may also vary. In the graduation project, you are expected to 1) understand the techniques to determine hydrogen isotope ratio of water and fatty acids of vegetable oil, 2) analyze hydrogen isotope ratios of rapeseed samples cultivated in agricultural fields with different soil properties; 3) determine soil properties, 4) discuss the outcome. Please contact Prof. Dr. Moritz Bigalke and Dr. Kaori Sakaguchi-Söder |
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Cave sediments – a subsurface buffer for microplastics? Only upon special request 4-5 months before starting your thesis work |
Karst areas with carbonate rocks and their caves cover 15% of the global land area. It is estimated, that 1 km² of karst area includes a minimum of 3-5 km cave length. Most caves are partly filled with cave sediments, eroded on the surface of the terrain, entered via runoff and temporarily deposited in the caves. As it is known, that microplastics are mainly transported via water-transport, cave sediments could act as an accumulation area for microplastics and therefore a subsurface buffer for microplastics emitted within caves catchment. Until know, less is known about microplastic transport in caves and their accumulation in cave sediments, not least because sampling in caves is extremely complex. The aim of this work is therefore to extract and analysis microplastic from cave sediment samples and subsurface water samples, to quantify microplastic fluxes within an exemplary cave system for the first time. Since sampling in this case is highly complex, the subject can only be started after a preparation time of 4-5 months, prior to the start of the thesis project. The project will be planned in cooperation with speleological working groups. Please get in contact as soon as possible, if you are interested in this special topic. Please contact Dr. Collin J. Weber |