Introduction:
Microplastics are man-made, small (<5 mm) low density plastic particles that are either manufactured directly, for use in cosmetics and various industrial applications, or formed by breakdown of larger plastic debris. Of the 275 million metric tons of plastic waste generated in 2010 4.8-12.7 million metric tons entered the ocean, a figure predicted to be an order of magnitude larger by 2025 (Jambeck et al., 2015). This high flux of microplastics into our environment and their high mobility and durability has meant they have become widely dispersed throughout aquatic environments where they present a severe threat, not only to marine wildlife and ecosystems but also human health (Sharma and Chatterjee 2017).
Most studies to date have focussed on in-situ observations of microplastic types and accumulation in sediments and the water column (e.g. Vianello et al., 2013; Gallagher et al., 2016), numerical modelling of microplastic distribution and transport pathways in different systems (e.g. Besseling et al., 2017; Hardesty et al. 2017; Kathmullina and Chubarenko 2019) and assessing the scale and threat of plastic pollution (e.g. Jambeck et al., 2015; Sharma and Chatterjee, 2017). However, there is limited information about the microplastic sediment budgets in sediment routing systems or the exact amounts and types of microplastics that are entering the world’s oceans (Hardesty et al. 2017, Kane and Clare 2019, Kathmullina and Chubarenko 2019).
This PhD project aims to study the microplastic sediment budget (or flux) in modern estuarine environments by quantifying the type and abundance of microplastic that goes into and comes out of the system, and what controls this. Modelling studies show that rivers are not just conveyors that funnel microplastics to the oceans, but that these environments can retain and store microplastic particles as well (Besseling et al., 2017). Estuaries represent a critical transition between fluvial and marine environments, and therefore hydraulic processes, and thus are ideal environments to study microplastic sediment budgets; notably quantifying the amount of microplastic that is prevented from entering the marine realm. Results of this project will fill the gap in knowledge about microplastic sediment routing in estuarine environments and provide crucial information that can advise the design of remedial action strategies as well as policies to minimise, or even prevent, further microplastic sediment pollution.
Project summary:
The candidate will use a combination of field and laboratory techniques to quantify parameters like the types, accumulation, residence time, age, and fractionation of microplastics in estuarine environments. Fieldwork will consist of sampling, this can include both water and sediment samples. The sediment itself can be collected both as surface samples as well as in sediment traps/gauges. Designing the sampling strategy and selecting the sampling locations will be part of the first phase of the PhD. The microplastic content of the samples will then be analysed using various methods including optical and SEM microscopy with EDS and Raman Spectroscopy to determine different types, shapes, sizes and other properties of the microplastics. Further into the project there are possibilities to incorporate flume experiments and/or numerical modelling (e.g. Delft3D) to further quantify the sedimentary processes that control the microplastic sediment budget in estuarine environments.
Qualifications:
The successful candidate should have an MSc (or equivalent) in Earth Sciences or closely related discipline, or have a background in Physics or Engineering if they have demonstrable affinity with sediment transport processes in natural environments. Experience with fieldwork, teaching, working with microscope/SEM data, and Matlab/Python (or equivalent) software would be an advantage.
This PhD topic is one of eight eligible for funding support through the recruitment of two Graduate Teaching Assistants within Geography & Planning and Earth Sciences at 0.5 FTE over a five-year period. The expectation is that no less than 50% of your time will be made available for the pursuit of your PhD or MPhil studies. In addition to your application for the PhD (detailed here), you are also required to apply for the 0.5 FTE University Teacher Salary: (£29,177 - £33,797 pa – at 0.5FTE pro rata) ensure that, in the funding section of the PGR application form, you mark your application ‘GTA SoES Post’.
For any enquiries please contact: Dr Iris Verhagen on: [Email Address Removed]
To apply for this opportunity, please visit: https://www.liverpool.ac.uk/study/postgraduate-research/how-to-apply/
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