PhD student: The effect of weathering on transport of microplastics in and from soils

Updated: about 2 months ago

Department of Soil and Environment

The Department of Soil and Environment is a leading soil research institution, both nationally and internationally. Our research focuses on fundamental soil properties and processes, as well as how soil functions are affected by changes in environmental conditions, including climate change. Through research, environmental analysis and education, we contribute knowledge about future sustainable land use and develop new solutions as a basis for decision-making in agriculture, forestry and the urban environment. The working environment at the department is international and we have around 100 employees.

Our research is carried out in seven subject groups with a focus on Soil Biology, Soil Nutrient Cycling, Soil Chemistry, Agricultural Water Management, Soil and Environmental Physics, Soil Mechanics and Soil Management, and the Biogeochemistry of Forest Soils. We are responsible for important research infrastructure in the form of soil chemistry and soil physics laboratories, an X-ray scanner, long-term field experiments, a lysimeter facility, and the field research stations at Lanna and Lövsta. The Department participates in approximately 30 courses at undergraduate and advanced level.

We are a part of the Soil, Water and Environment Center at SLU (MVM-center), which provides links to research on water systems, recycling and bioenergy. Our work is aligned to national environmental and climate goals as well as to the Sustainable Development Goals. We are situated at Campus Ultuna in Uppsala and in Skara. Read more about the department here ( ).

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The effect of weathering on transport of microplastics in and from soils
Research subject: Soil science

We have come to realize that plastic pollution is everywhere. While there is much focus on marine plastic pollution, much higher plastic amounts are emitted to soils, in particular soils where organic residues such as wastewater treatment sludge are used or soils where plastic films are applied. Plastic is commonly found in these soils as micro- or nanoplastics that can be transported downward or horizontally from soils to freshwater environments nearby. Studying the rates of these transport processes helps predicting the current and future exposure concentrations in soils and how soils can be sources of plastics for e.g. freshwater environments. However, such rates are usually determined for pristine, i.e. as-produced plastic particles. This Ph.D. project will investigate which changes occur to plastics in soils as a result of weathering and whether these changes also affect the rates of vertical and horizontal transport processes via advection, bioturbation or erosion. Plastics will be isolated from soils from long-term field experiments that have been exposed to plastics since many years. The surface properties of these plastics will be studied using FTIR and NMR. We will then weather metal-labelled plastics artificially using mesocosms or UV chambers. These particles can be tracked conveniently using ICP-MS allowing us to study vertical and horizontal transport and comparing with pristine plastics. The improved knowledge on realistic transport rates will be used to more accurately predict plastic mass balances in topsoils and whether contaminated soil are sources of plastics to nearby rivers. We will also be able to better inform regulatory agencies on how to interpret existing ecotoxicological and fate data that has hitherto mostly been gathered for pristine microplastics.

The PhD project will be mostly done at the department of Soil and Environment, SLU in Uppsala where the Ph.D. student will be supervised by Dr. Geert Cornelis. Ph.D. training will be organized by the research school Focus on Soils and waters. The project occurs in collaboration with ETH (Prof. Denise Mitrano) and Agroscope (Dr. Thomas Bucheli) that will also assist in co-supervision. SLU infrastructure and these collaborations allow working with techniques such as ICP-MS, NMR, micro-FTIR, Py-GC-MS. Interaction with society and the wider public is an important part of the project. The project has, for instance, an advisory board with members from the Swedish EPA (Naturvårdsverket), wastewater treatment industry and agricultural consultants to which the PhD student will regularly report.


An MSc degree in environmental science, chemistry or environmental engineering including documented knowledge in soil science. Candidates with a soil science background should have a documented knowledge in (material) chemistry. A proven good ability to communicate in written and spoken English is required. It is also required that the candidate can demonstrate an ability to independently develop hypotheses and experimental protocols. If applicants have laboratory experience in soil physics e.g. via their bachelor, masters or other projects, this is considered a merit. Previous experience with microplastics and their analysis using micro-FTIR and/or Py-GC-MS is also a merit. A very good ability to express yourself in English in both speech and writing is required.

Place of work:      


Forms for funding or employment:

Employment (4 years)

Starting date:

According to agreement.


Click the “Apply” button to submit your application. The deadline is 2024-02-29.

To qualify for third-cycle (Doctoral) courses and study programmes, you must have a second-cycle (Master’s) qualification. Alternatively, you must have conducted a minimum of four years of full-time study, of which a minimum of one year at second-cycle level.

Applicants will be selected based on their written application and CV, degree project, copies of their degree certificate and transcript of records from previous first and second-cycle studies at a university or higher education institution, two personal references, and knowledge of English. More information about the English language requirements can be found here:

Please note that applicants invited to interview must submit attested copies of their degree certificate, or equivalent, a transcript of records from previous first and second-cycle studies at a university or higher education institution. Applicants who are not Swedish citizens need to submit an attested copy of their passport’s information page containing their photograph and personal details.

Read about the PhD education at SLU at

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The Swedish University of Agricultural Sciences (SLU) has a key role in the development for sustainable life, based on science and education. Through our focus on the interaction between humans, animals and ecosystems and the responsible use of natural resources, we contribute to sustainable societal development and good living conditions on our planet. Our main campuses are located in Alnarp, Umeå and Uppsala, however, the university also operates at research stations, experimental forests and teaching sites throughout Sweden.

SLU has around 3,000 employees, 5,000 students and doctoral students and a turnover of over SEK 3 billion. We are investing in attractive environments on all of our campuses. We strive to provide a work environment characterised by inclusivity and gender equality, where different experiences generate conversations between people and pave the way for science, creativity and development. Therefore, we welcome applications from people with diverse backgrounds and perspectives.

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