Host Faculty: Engineering
General Subject Area: Civil Engineering
Project Level: PhD
Microplastic pollution is an emerging and persistent threat to aquatic environments, with urban stormwater runoff now recognised as a major transport pathway. Microplastics derived from tyre wear, synthetic textiles, urban litter, and degraded plastics are mobilised during rainfall events and discharged into freshwater and coastal systems. In Aotearoa New Zealand, the limited microplastics research to date has largely focused on coastal and wastewater environments, leaving a critical gap in understanding microplastic behaviour within urban stormwater systems.
Nature based stormwater (NbS) treatment systems—such as raingardens, swales, and infiltration basins—are increasingly implemented to improve water quality and manage urban runoff. While these systems have demonstrated capacity to reduce pollutant loads, existing national and international research on microplastics has focused predominantly on characterisation and removal efficiency under controlled conditions. There is limited understanding of how microplastics are transported, retained, accumulated, and potentially remobilised within NbS systems during dynamic storm events. Yet this understanding of microplastics behaviour within such systems is crucial if we are to optimise our management of these persistent pollutants in our existing and future NbS infrastructure.
This project aims to develop a process-based understanding of microplastic fate within urban NbS systems by explicitly linking microplastic physical properties (size, shape, and density) with storm event hydrodynamics. The research is novel in shifting beyond removal metrics to examine mechanisms of filtration, sedimentation, flotation, storage, and remobilisation under real storm conditions.
The research will use a field-based approach centred on operational NbS systems in Christchurch and Auckland, sampled across different catchment types. Auckland Council will guide site selection for Auckland, and we will then use these selection principles to also select relevant Christchurch sites. Sampling at system inlets and outlets will capture event-scale microplastic fluxes, including first flush dynamics. Both intra-event and inter-event sampling will be undertaken to capture microplastics behaviour at a variety of temporal scales. Field observations will be supported by controlled laboratory column and flume experiments to isolate specific transport and retention processes under defined hydrodynamic conditions.
Microplastic quantification and characterisation will be undertaken using microscopy for count-based analysis and FTIR spectroscopy for polymer identification and characterisation. Targeted pyrolysis GC/MS analysis will be used to identify key polymers such as tyre-wear particles. NbS treatment media coring will assess spatial and depth dependent accumulation of microplastics in existing systems, allowing evaluation of long-term storage and potential remobilisation risks during high intensity storms. Forensics of the column and flume media from the lab experiments will also support this analysis.
By integrating hydrological, physical, and chemical data, the project will develop a decision support tool linking storm characteristics and microplastic particle properties to nature-based stormwater system performance. This mechanistic understanding will enable targeted improvements in system design, inform retrofitting of existing assets to enhance microplastic retention and reduce remobilisation, and guide maintenance strategies such as sediment and treatment media management. The outcomes will provide the first field-based evidence of microplastic behaviour in New Zealand stormwater treatment systems, supporting more effective, resilient, and evidence-led urban water infrastructure and policy.
Supervisors
Primary Supervisor: Frances Charters
Other Supervisor(s): Hamish Mackey, Sally Gaw
Key qualifications and skills
A strong academic background in Civil Engineering, Environmental Engineering, Chemical and Process Engineering, Applied Chemistry, Environmental Science, or a related discipline.
Knowledge of hydrological, environmental, or water treatment processes.
Experience in field-based environmental investigations and/or laboratory experimentation.
Strong quantitative data analysis and problem-solving skills.
Interest in contaminant fate and transport, particle behaviour, or urban water systems.
Experience with analytical characterisation techniques (e.g. FTIR, microscopy, pyrolysis GC-MS) is advantageous.
Experience with programming and data analysis tools (e.g. R, Python, MATLAB) is desirable.
Excellent written and verbal communication skills.
Ability to work both independently and within multidisciplinary research teams.
Enthusiasm for addressing environmental challenges through innovative, evidence-based research.
Does the project come with funding
Per annum: Stipend of $32,650 plus PhD tuition fees
Funding duration: Three years (360 points)
Final date for receiving applications
15 September 2026 (midnight)
How to apply
This is a UC Connect Scholarship and applications must be made through the Scholarship Portal in your myUC account. Emailed applications will not be considered. Find out more here: University of Canterbury Scholarship Portal - UC Connect - Urban microplastic capture
Keywords
urban runoff; pollutants; hydrodynamics; treatment performance; microscopy; FTIR; pyrolysis GC-MS
