The assessment of the sources, abundance and composition of microplastics (MPs) present in the environment is a significant challenge, as annually, hundreds of millions of plastics are produced and deposited in the environment, thus posing real threats. Hence, MPs are more frequently perceived as first-order environmental pollutants potentially harmful to the health of many groups of organisms. To explore the current knowledge in this field, we reviewed the scientific literature (published mostly in the last 20 years) focussing on the presence of MPs in water and sediments and their impacts on aquatic ecosystems. Chinese and US scientists play a leading role in this research field. The most commonly used methods of identification and quantification of synthetic polymer particles are Fourier-transform infrared spectroscopy and Raman spectroscopy due to their high effectiveness. However, advances in measurement analytics have resulted in the constant development of more accurate methods of collecting and detecting MPs in environmental samples, necessitating the unification of these methods to develop standard analysis procedures. Our paper summarises the current knowledge about the sources, transport and circulation of MPs in the environment, based on methods used for identification of the compounds, starting from sample collection, detection and description to their quantification in water, sediments and biota of freshwater ecosystems. This holistic approach necessitates focusing research on the importance of MPs in the EcoHealth approach, examining the impact of changes in the global ecosystems on human health. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of European Regional Centre for Ecohydrology of the Polish Academy of Sciences.