Do microplastics pose a threat to the terrestrial biosphere?

Understanding the behaviour, fate and environmental risk of microplastics in the plant-soil system


Contamination of the terrestrial, freshwater and marine biosphere by microplastics is now widely recognised as one of the world’s greatest pollution threats. Microplastics (plastic particles <5 mm in size) originate from the fragmentation of large plastic litter or from direct environmental release. Their potential impacts on terrestrial ecosystems remain largely unexplored despite the overwhelming evidence of their negative effect on marine organisms. Most plastics arriving in the oceans were produced, used, and often disposed on land. Consequently, it is within terrestrial systems that microplastics might actually be of greatest concern. Despite this, we know very little about how these microplastics behave in the plant-soil system.

Aid agencies operating in OECD-target countries have widely promoted the use of plastic soil coverings within agriculture to promote food security. Unwittingly, however, this has caused mass plastic pollution in agricultural soils. In China, where the problem is most severe, microplastic contamination and associated toxins now affects 20 million hectares of farmland with this predicted to increase by a further 10 million hectares over the next decade. 

From the available evidence, it is clear that we need to (i) better quantify the impact of this plastic contamination on plant and soil health, and (ii) demonstrate the benefits of more sustainable alternatives (i.e. bioplastics).

This project addresses a topic of major international significance. The key aims of the studentship are therefore to (i) quantify the damage that microplastics (and bioplastics) have on plant and soil health; (ii) investigate whether the plastic additives (e.g. phthalates) are more toxic that the plastics themselves; (iii) measure rates of plastic and bioplastic degradation in soil, (iv) publish high quality journal papers to promote the student’s career, and (v) provide guidance to landowners, policymakers, and environmental agencies.

For more background information, see the suggested readings below.

As part of this PhD the applicant will: 

  • Conduct fieldwork in Western Australia to collect material for use in experiments.
  • Use stable and radio-isotopes to monitor plastic degradation in soil.
  • Learn the latest imaging technologies to visualise plastic behaviour in soil.
  • Gain experience in molecular biology to understand how microplastics affect soil and plant health.
  • Undertake some experiments in the UK (and potentially China) at established microplastic field trial sites.
  • The applicant will be expected to write a minimum of three peer-reviewed publications.
Cross section of soil in a wheat field

Research team leaders:
Professors Davey Jones, Daniel Murphy and Andy Whiteley

Professors Davey Jones and Daniel Murphy specialise in understanding below-ground processes with specific focus on nutrient and carbon cycling in soil-plant-microbial systems and understanding how anthropogenic perturbation (e.g. climate change, pollution, extreme events) affect functioning of the terrestrial biosphere. Prof. Jones leads a radio-isotope tracer laboratory and Prof. Murphy leads a stable isotope tracer laboratory. Prof. Andy Whiteley is a molecular ecologist who investigates soil function and diversity in soil and water. This PhD studentship is based with these staff in the UWA School of Agriculture and Environment.


External collaborators:
  • Prof. David Chadwick (University of Bangor, UK)
  • Prof. Changrong Yan (Chinese Academy of Agricultural Sciences - CAAS, China)


PhD opportunities

Interested in becoming part of this project? Complete the following steps to submit your expression of interest:

Step 1 - Check criteria

General UWA PhD entrance requirements can be found on the Future Students website.

Requirements specific to this project:

  • You will need to have completed a Honours or Master's degree at time of admission. Preferably this should be in Biology, Environmental Science, Soil Science, Plant Biology, Agriculture, Ecology or a related subject
  • Experience in undertaking and writing up experiments
  • Leadership skills and the ability to work in a team is a requirement
  • Good understanding of statistics and statistical models is preferable
  • Applicants having already published in a scientific journal will be highly considered, however, this is not a prerequisite
  • Be comfortable with long-distance travel (to the UK) to undertake collaborative work and also national travel to attend conferences etc.

Step 2 - Submit enquiry to research team leader

Step 3 - Lodge application

After you have discussed your project with the research team leader, you should be in a position to proceed to the next step of the UWA application process: Lodge an applicationDifferent application procedures apply to domestic and international students.