Thesis abstract:

Microplastics (MP) are emerging pollutants and their containment by geoenvironmental engineering barriers is of high interest. Most studies of MP in the environment have focused on their distribution and abundance in aquatic environments and their impacts on human and ecological health. A few investigations have been conducted on MP prevalence and transport in sandy soils. However, little is known about the interaction between MP and clayey soils and materials widely used in barrier systems and whether the presence of MP changes the effectiveness of clay as a buffer against organic and inorganic contaminants.

This research aims to better understand the transport and retention of MP in clayey soils, as well as their effects on clay’s interaction with inorganic contaminants. Two research questions will be addressed:

1. How do MP migrate through, and sorb onto, bentonite clay, under conditions encountered in barrier systems, and what are their effects on bentonite’s microstructure?
2. What is the effect of MP presence on the ability of bentonite clay to act as a buffer against heavy metals?

Column tests and vibrational spectroscopies, including Raman and Fourier transform infrared (FTIR), will be used in the investigation. Experimentally validated, heuristic numerical models will be developed. The research will make a contribution towards protecting groundwater resources from MP and other surface contaminants.