Analysis of the substance class distribution of the total number of substances recorded per year reveals several research trends (Fig. ). The rise in the recorded number of polymers also demonstrates the increase interest in studying this phenomenon. More interesting is the rise of organic/inorganic small molecules from 2017 onwards, in part due to interest in identifying and measuring small molecules and monomers released during plastic degradation. A general look into academic publications also shows the growing concern of pollutants from the environment and chemical additives used in manufacturing seeping into living organisms from microplastics, among other things. The elements class has also increased significantly in 2020 and 2021. For example, carbon (specifically activated carbon) is being studied for water treatment and purification, including the removal of microplastics. Other examples for the appearance of elemental carbon in literature includes the activation of carbon metabolism due to presence of microplastics in plants, methodology development to exclude carbon particles (ex: carbon black) when measuring microplastics, and how microplastics can affect the carbon cycle. The development of carbon-based catalysts derived from microplastics is also discussed in academic literature. The elements class is also increased due to the identification of microplastics as vectors for elements like As, Cd, Cr, Cu, Pb, Mn and Zn via the heavy metal absorption of the different polymers that are the main components of microplastics.