Raphael Rehm

HS Hydrological Sciences

The 2021 Virtual Outstanding Student and PhD candidate Presentation (vOSPP) Award is awarded to Raphael Rehm for the poster/PICO entitled:

The transport of microplastic on agriculture soils via soil erosion (Rehm, R.; Zeyer, T.; Fiener, P.)

Click here to download the poster/PICO file.

Raphael Rehm is a PhD-Student in the Water and Soil Resource Research group at the Institute of Geography at the University of Augsburg, Germany. His research is focused on measuring and modelling the export of microplastic from agriculture areas caused by soil erosion and surface run-off within the Danube river catchment of Germany.

Soil erosion is a potentially important source of microplastic (MP) entering aquatic ecosystems. However, little is known regarding the erosion and transport processes of MP from agricultural topsoils. The aim of the presented study was to analyze the erosion and transport behavior of MP during heavy rainfall events, whereas a specific focus is set to preferential MP transport and MP-soil interactions potentially leading to a more conservative transport behavior. The study is based on a series of rainfall simulations on paired-plots (4.5 m x 1.6 m) of silty loam and loamy sand lo-cated in Southern Germany and shows a preferential erosion and transport of the MP. There was a higher MP enrichment on the loamy sand but a higher sediment delivery on the silty loam resulting in nearly equal MP deliveries from both soil types. An increasing interaction with mineral soil parti-cles or aggregates leads to a decreasing MP delivery over time. Within 1.5 years, up to 64% of the eroded MP particles were bound to soil particles. Overall, more of the coarse MP (250-300 µm) was laterally lost via soil erosion, while for the fine MP (53-100 µm) the vertical transport below the plough layer was more important. In general, our study indicates that arable land susceptible to soil erosion can be a substantial MP source for aquatic ecosystems.