Distribution and dynamics of microplastics in soils

Plastic pollution constitutes a major problem in global ecosystems. Over the past decades, scientific research on the presence of plastics in the environment has grown significantly. Initially this research has mainly focussed on aquatic ecosystems: marine environments, rivers and shorelines. Over the last decade an increasing amount of research was dedicated to plastic pollution in soils. It is estimated that 80% of the amount of plastics that is present in the oceans was originally land-based and that the amount of plastics in terrestrial environments is much larger than in aquatic ones. Most attention has been given to microplastics, defined by the NOAA as particles that are smaller than 5 mm. They are small enough to enter the food chain and may also absorb pollutants. The purpose of this PhD research is to investigate the dynamics of microplastics in the soil from a pedological point of view. It aims at investigating the relation of microplastics to specific soil characteristics, like organic matter, soil structure and texture. Moreover, the research will focus on the distribution and dynamics of microplastics in relation to their degradability, bioavailability and transport through the soil. An important aim of the research is to develop a suitable methodology to investigate the presence of plastic fragments in soil samples. This includes the sampling process, extraction as well as identification and quantification, as there is no standardized methodology yet to investigate the presence of microplastics in the soil.