Microplastics in agricultural soils: a new challenge not only for agro-environmental policy?

Microplastic pollution has recently gained the attention of the public media, politics and research. Microplastics (i.e., plastic particles less than 5mm in size) have been identified as a global environmental threat for terrestrial and aquatic ecosystems and human health. Agriculture is assumed to be both victim and polluter of microplastic pollution. Agricultural soils receive microplastic immissions from tire wear and fragmented macroplastic that enters the environment through littering. Furthermore, farmers who fertilize their arable land with sewage sludge and compost unintentionally apply the microplastic particles contained in these biosolids. On the other hand, agricultural soils may emit microplastics into aquatic environment. Because of this ambivalent position as both victim and polluter, the information on microplastic pollution is of current interest for agricultural production and might become a relevant topic for agro-environmental policies in the future. Our research aims to quantify the microplastic immissions into agricultural soils and emissions from agricultural soils into aquatic systems. We use different analysis approaches and interdisciplinary modelling to address these aims for two case studies in Germany. Because research in microplastics is a relatively new concern, we combine different methodological approaches in a complementary way.