Gemma Shaw

PhD Summary

Saprolite, physically intact but chemically weathered bedrock, sits as a boundary layer between the soil profile and unweathered bedrock. It weathers into soil. Saprolite has distinctive properties which would affect how a contaminant behaves in this zone compared to in the soil or bedrock. There is currently a gap in knowledge about the extent to which saprolite can act as a source or sink for different contaminants under different conditions. This is particularly timely in the context of more novel or persistent contaminants, including but not limited to: microplastics, pharmaceuticals, PFAS, bacteria, hydrocarbons and so on. The role of saprolite in the transport, storage and potential re-release of contaminants has implications for future soil health, as well as wider environmental and water quality.  

This project will review the current evidence on the presence and behaviour of contaminants in saprolite and use this to inform digital mapping of saprolite and contamination risks, fieldwork sampling of saprolite contamination, mesocosm experiments and modelling. This will enable the identification and quantification of both natural processes and risks.  

Previous activity

Before my PhD, I studied Earth Sciences (BA) at the University of Cambridge and then Hydrogeology (MSc) at the University of Birmingham.  

I loved the courses and carried out undergraduate research on the geometry of normal faults and rift basins, and on the morphology and petrology of ureilite meteorites. I did my master’s dissertation on nanoparticle mobility in porous media, measured experimentally using magnetic susceptibility.  

I interned with the Cambridge Deep Earth Seismology Group producing teaching resources for schools and with Mott MacDonald as a Hydroinformatics intern.  

Why did you choose CENTA?

The support and training that CENTA provides was very attractive, as well as the network of other PhD students you can be part of. For me, a key benefit within CENTA is that my project involves significant collaboration with the British Geological Survey.