Master thesis topics
1. Exposure modeling of microplastics in the environment
Plastics are one of the most important materials of our time and the way we live would not be possible without them. Because plastics are not biodegradable, they are stable in the environment once they have been released and are only moved around by flow processes and are broken into smaller and smaller pieces. The large plastic litter only represents the visible part of the problem. Of equal importance are so-called microplastics, small pieces of broken-down plastic in the mm to sub-mm range that have first been identified in the oceans.
It is the aim in this project to build up a dynamic model to predict the mass flows of plastic and microplastic to the environment for various polymers. Basis of the model are the flows of macro- and microplastic through the anthroposphere and their use in products. Release to the environment is quantified dueing all stages of the life cycle. The combination of a dynamic material anaylsis model with a release model will allow to quantify the amount of all plastic ever released to the environment.
2. Microplastics release from textiles
The occurrence of microplastics, small plastic pieces less than a few mm, in natural systems such as soils and sediments is currently a topic that receives a lot of attention. Very little is known about actual sources of microplastics. The aim of this work is to investigate one possible source, the release of microplastics from textiles during washing and wearing. In this work a systematic approach will be used to understand the processes that result in release of microplastics from various fabric and polymer types. The results of this work will be very useful to quantify the contribution of washing to the microplastics load in wastewater and air.
3. Natural fibers or microplastic from textiles – what is more problematic?
Textile fibers are released to environmental compartments during production, use and end of life. There are assumptions that washing of synthetic textiles is one of the main sources of primary microplastic fibers in oceans. Therefore, textiles made from natural fibers and bio-based polymers are seen as a strategy to reduce the environmental risks. However, also natural fibers and bio-based textile polymers are released in relevant quantities to the environment and their fate (e.g. biodegradation) is not well investigated.
This master thesis will look at the question if microplastic fibers released from textiles are really worse than natural fibers. A material flow analysis is the basis to evaluate the potential exposure to these fibers. This will then be combined with the state of knowledge about the hazards and fate (e.g. biodegradability of fibers under natural conditions) in order to assess these risks of released textile fibers. This involves:
• to collect all relevant market data for textile fibers (e.g. Polyester, Polyethylene, Polyamide, cotton, viscose, linen, wool, silk)
• to evaluate and interpret the data
• to establish a MFA of textile fibers
• to collect data on biodegradability of natural fibers
• to collect data on hazards of fibers
• to evaluate the environmental risks
4. Exposure and risk modeling of nanomaterials in the environment
Engineered nanomaterials (ENM) are already contained in many products and high growth rates are expected in the next years. During various stages of the life cycle of a product ENM can be released into the environment, e.g. during production, use, recycling or disposal. In order to conduct a realistic environmental risk assesment of ENM, we have to know the expected concentrations in environmental compartments such as water, soil and sediments. These concentrations can then be compared to ecotoxicological limits.
The aim of this work is:
- to model the concentrations and the effects of ENM in the environment based on a life-cycle perspective
- to evaluate the ecotoxicological literature
- to perform an environmental risk assessment for nanoimaterials.
Risk modeling of nanomaterials is a core topoic of the ERAM group. Topics for a specific master thesis can be in one or all of these three points, depending on the interest of the student and the state of the projects where the thesis will be embedded in.