Microplastic Transport with Runoff and Erosion

Plastic pollution is increasingly recognised as an enormous environmental and societal problem. Microplastic (< 5 mm) input to soils is estimated to be 40 times larger than input to surface waters. MPs accumulate in agricultural soils due to plastic mulching and application of polluted organic amendments such as sewage sludge and compost. Evidence on how microplastics affect soil hydrological and physical properties is limited and contradictory, while this can greatly affect the soil structure, soil water balance, infiltration and water holding capacity, in turn affecting runoff generation and erosion on sloping land. While soil erosion is the most common land degradation problem worldwide, how MPs are transported with runoff and erosion is virtually unknown. My research focusses on the effects of microplastics on soil hydrology using multiple laboratory experiments and modelling. I will work closely with a fellow PhD-candidate, who will focus on quantifying MPs’ effect on soil structure and aggregate stability using microcosms experiments and modelling. My research consists of the following steps: 1. Quantify MP transport with runoff and erosion at field scale; 2. Investigate how MP-induced changed soil structure and hydrological properties affect runoff generation, erosion and MP transport 3. Incorporate MP effects on soil hydro-physical properties and transport processes of MPs with erosion into an existing soil erosion model 4. Calibrate and validate the model using field observations & upscaling of MP transport with erosion The research outcomes will greatly contribute to our knowledge on MP transport with runoff and erosion.