Project highlights

  • Investigate flow of microplastics in our environment
  • Assess impact of microplastics on soil nutrients
  • Work with leading UK water companies


The impact of plastics on our environment has gathered huge attention recently following the awareness raised by the BBC landmark series, Blue Planet II where the Open University was a partner. There is a growing public drive and commitment from all stakeholders to remove plastics from our environment through identification of the level of pollution, implementation of clean-up operations (such as beach cleaning) and reduction of usage. It is relatively easy to identify and clean up large and visible plastics present in our environment, but once these are broken down into smaller particles such as microplastics (MPs), it is extremely challenging to identify their presence, record their movement and clean them up. MPs have now been identified everywhere on Earth, yet we know little about their impact on our living environment.

The presence of MPs (<5 mm to 500 m) in our natural water system is well known. However, the flow of MPs from the source to our environment through the water cycle, into the soil and its impact on soil nutrients are less well quantified. Additionally, a recent study of UK Water Industry Research showed that our water treatment plants are effectively removing MPs but revealed the presence of MPs in the wastewater and sludge treatment line1. One-way MPs are finding ways into the soil is land application of sewage sludge and from wastewater discharged into the water bodies2. This project will investigate: how MPs move from the wastewater and sludge into our living environment and its impact on soil nutrients, biota and plants. The sampling of water and sediments at the source to the exit point will be carried out to identify flow3 of MPs in the natural and wastewater systems, interaction of MPs on soil nutrients and impact on soil biota and plants.


The Open University


  • Climate and Environmental Sustainability
  • Organisms and Ecosystems


Project investigator

  • Yoseph Araya (Open University)


  • Pallavi Anand, Open University
  • Wesley Fraser (Oxford Brookes/OU)
  • Peter Vale (Severn-Trent Water)
  • Kate Salmon (Met Office)

How to apply


To investigate flow of MPs in water systems, water samples will be filtered using 63 mm sieve to extract particles including MPs. The MPs from sediment and soil samples will be extracted using a density separation technique3&4. Approximately 10g of sediment subsample will be first wet sieved through a 63 mm sieve to separate the silt/clay and sand fractions as any smaller particles cannot be reliably identified as plastic material4. The sand fraction will then be oven dried at 50°C. Triplicate samples will be processed. Dried samples will be analysed under binocular microscope to identify distribution of MPs. At the OU further, chemical identification of MPs will be carried out using the Fourier Transform Infrared (FTIR) technique as well as soil nutrient analysis. Data will be assessed with open source trajectory modelling, as necessary, to assess flow of MPs in natural system4.

Training and skills

Student will be trained in sampling techniques, laboratory skills (PA, WF and YA), statistical (YA) and modelling (KHS) methods. Student will have an opportunity to work with Severn-Trent Water in sample collection and processing (PV). Student will acquire a wide range of skills through this project to get trained in skills for a potential to explore future employability in UK water company/Severn-Trent Water.

Partners and collaboration

The project offers extensive opportunities for the student to interact and collaborate with scientists involved in complementary research. This project benefits from project partners Severn Trent Water and Met Office and access to sampling and modelling techniques.

Further details

Students should have a strong background in environmental science, soil or biogeochemical sciences. Experience of laboratory analysis and a strong interest in topical environmental issues are highly desirable. The successful student will join a well-established interdisciplinary team researching ecosystem processes utilizing diverse set of chemical and physical analysis methods. The school ‘s substantial number of students make up part of the vibrant postgraduate community at the Open University.

Please contact or for further information.

Applications should include:

  • an academic CV containing contact details of three academic references
  • a CENTA application form
  • and an Open University application form,downloadable from:  UK OU application form (for UK-based applicants, see below) or Overseas OU application form (for overseas applicants, see below)

Applications should be sent to  by 11th January 2021 

Possible timeline

Year 1

Read literature, define sampling plan and collect water and sediment/soil sampling and sludge treatment line. Process samples for one study site and learn statistical treatment of data to carry out data analysis.

Year 2

Interpret data and write while continue with sample processing from other sites collected in year 1. Carry out year 2 sampling and process samples and data. Carry out flow of MPs modelling. Potential publications on methods and results.

Year 3

Finish analytical work, compile all data and carry out data analyses. Prepare manuscript and write remaining papers and/or Thesis chapters. Submit thesis.

Further reading

  1. UK Water Industry research report:
  2. Wang, J., Liu, X., Li, Y., Powell, T., Wang, X., Wang, G., and Zhang, P. (2019) Microplastics as contaminants in the sil environmentL A mini review, Science of the total environment, 691, pp. 848-857.
  3. Hurley,R., Woodward,J. and Rothwell, J. J. (2018) ‘Microplastics contamination of river beds significantly reduced by catchment-wide flooding’, Nature Geosciences, 11, pp. 251-257.
  4. Hidalgo-Ruz, V., Gutow, L., Thompson, R. C., and Thiel, M. (2012) ‘ Microplastics in the Marine Environment: A reivew of the Methods used for identification and quantification’, Environmental Science and technology, 46, pp. 3060-3075.


The project does not require working in large groups and will therefore be resilient to further restrictions in rules on aggregating outdoors. Fieldwork and lab work will be carried out alone or in pairs and will be in line with rigorous OU field safety risk assessment.