Microplastics and nanoplastics in agriculture—A potential source of soil and groundwater contamination?

An overview of the current state of knowledge on the pollution of agricultural soils with microplastic and nanoplastic (MnP) particles is provided and the main MnP sources are discussed. MnP transport mechanisms from soil to groundwater, as well as the potential impact of MnPs on soil structure are considered, and the relevance of co-contaminants such as agrochemicals is further highlighted. We elaborate on why MnPs in soil and groundwater are understudied and how analytical capabilities are critical for furthering this crucial research area. We point out that plastic fragmentation in soils can generate secondary MnPs, and that these smaller particles potentially migrate into aquifers. The transport of MnP in soils and groundwater and their migration and fate are still poorly understood. Higher MnP concentrations in agricultural soils can influence the sorption behavior of agrochemicals onto soil grains while attachment/detachment of MnPs onto soil grains and MnP-agrochemical interactions can potentially lead to enhanced transport of both MnP particles and agrochemicals towards underlying groundwater systems.