Soils, a key interface in the global environment, are of vital importance in supporting ecosystems and feeding the global population. In modern agriculture, plastic products are used for various purposes. Over time, larger macroplastic pieces break down to smaller particle sizes called microplastics (MPs) and nanoplastics (NPs), a ubiquitous group of anthropogenic pollutants that have been detected in baseline quantities of 0.002% of dry soil weight, with hotspots up to 7% of soil dry weight. Furthermore, polymers may be delivered directly to agricultural systems through e.g., application of plant protection products and polymer seed coatings. Microplastics pollution has already been shown to influence microbial communities and soil invertebrates in scenarios with high exposure concentrations and nanoplastics have been shown to be taken up by crop plants. The physical properties of soils have been shown to be altered by MPs inclusion, including soil pore connectivity, bulk density and water holding capacity, which can be of critical importance when considering preserving the productivity of agricultural soils. However, there is a knowledge gap in understanding the mobility of MPs and NPs from agricultural soils. Waterways globally are threatened by poor water quality, to which MPs and NPs can contribute to the increasing burden of nutrients and contaminants resulting from agricultural runoff. In this project, we plan to simultaneously assess runoff of MPs and NPs from soils, how they are transported to waterways, and impacts on soil ecosystem services.

We aim to establish custom-built small-scale laboratory plots which will enable the simultaneous assessment of soil erosion and MPs and NPs movement through the soil profile, both vertically and laterally. These aspects will be assessed across a range of soil textures, slope, and rainfall intensities to understand how plot characteristics influence MPs and NPs transport. Using model particulate plastics that have previously been developed in-house containing trace metals will enable quantification of plastic particles throughout the experimental system. This approach offers several advantages, including being able to accurately and quickly quantify MPs and NPs in complex matrices by using the metal as a proxy for plastic using trace metals analysis techniques, such as ICP-MS. Consequently, we will be able to assess how effects on soil erosion and the transport of MPs and NPs varies with the properties of the size, morphology and polymer of the particles, soil texture and plot characteristics. The successful candidate will perform laboratory experiments to generate primary data to understand these processes but can also expand upon this work by developing fate and transport models if desired. The diverse nature of plastic research involving environmental science, analytical chemistry, and materials science will allow the successful candidate to perform multidisciplinary research. 

This position is offered as one of 14 fully funded Ph D positions funded by the Marie-Skłodowska-Curie Actions Doctoral Network PlasticUnderground. The PlasticUnderground Doctoral Network (DN) is an international, multi-partner, inter-sectoral doctoral research-training network with the aim to prepare an international cohort of Doctoral Candidates in the development of solutions to the emerging plastic pollution crisis in soils and groundwater. Given the evolving understanding of subsurface soil and groundwater ecosystems as long-term storage pools of micro- and nanoplastics, interdisciplinary capacity that can support and provide guidance for the management of these systems, as well as development of adequate technological, social behavioral and legislative solutions is urgently needed. This interdisciplinary DN will integrate comprehensive training opportunities in cutting edge technological innovations, regulatory and behavioral approaches across traditional disciplinary and sectoral boundaries. The consortium comprises universities, research institutions and companies located in the UK, France, Spain, Serbia, Italy, Switzerland, Cyprus and Germany.

• You should hold a Masters degree in environmental science, environmental engineering, geochemistry, agronomy, geology or a related field.
• Experience with soil ecosystems, analytical method development and characterization and quantification of particles (microplastics, nanoparticles, colloids) or heavy metals would be an asset.
• There is flexibility in the precise research goals and objectives which will ultimately be undertaken as long the proposed project fits within the general theme described above.
• You are welcome to creatively propose research activates which fit their skillsets and interests along the themes of this open position as long as it fits within the context of our working group.
• The ability for independent, organized work is essential.
• Teamwork is also important as you will be integrated into a team with diverse research backgrounds, both within the PlasticsUnderground DN and within the host laboratory.
• The working language is English, and advanced communication skills in English (oral and written) are expected.

The selected candidate can be of any nationality but must comply with mobility rules of the PlasticsUnderground DN: At the time of selection by the host organization, they must not have resided or carried out their main activity (work, studies, etc.) in the country of their host organization for more than 12 months in the three years immediately prior to their recruitment.

This Ph.D. position is hosted by Prof. Denise M. Mitrano at ETH Zurich who leads the Environmental Chemistry of Anthropogenic Materials (ECAM) Group. Our research focuses on the distribution and impacts of anthropogenic materials in technical and environmental systems, and we are particularly interested in developing analytical tools to systematically understand the fate, transport and biological interactions of particles, such as metal colloids, engineered nanomaterials and microplastics. Our results can inform risk assessments of anthropogenic pollutants and propose solutions for sustainable freshwater and soil management. We work as an interdisciplinary team of environmental scientists, environmental engineers, analytical chemists and biologists with diverse scientific backgrounds coming from across the world, and we find this diversity an asset in building a creative and dynamic working environment. You can find more information on our research activities at: www.ecam.ethz.ch

The position is fully funded for 4 years, 3 of which are part of the PlasticsUnderground DN. Ph D salaries will be in accordance with ETH standards. In addition to the world class facilities at ETH Zurich, the PlasticsUnderground DN will provide ample opportunities for international and inter-sectoral secondments, International Joint Experiments, Advance Training Courses (ATCs) among other activities. Consequently, the candidate is expected to travel internationally during the appointment. 

We look forward to receiving your online application with the following documents, by April 7, 2023:

• motivation letter
• CV
• a short summary of Masters thesis
• contact information for 2-3 potential references.

Please note that we exclusively accept applications submitted through our online application portal. 

Suggested starting date: July l, 2023 (or upon mutual agreement)

For further questions on the advertised position, please contact Prof. Denise M. Mitrano (denise.mitrano@usys.ethz.ch) (no applications please)

For recruitment services the GTC of ETH Zurich apply.