Sampling and analyzing microplastics in rivers: What methods are being used after a decade of research?

Microplastic pollution in rivers has been a focus of research for more than a decade now. Studies have been conducted all over the world in an attempt to quantify and characterize these emergent pollutants in freshwater. However, the lack of homogeneity in the methods used in various studies makes it difficult to draw conclusions or general patterns. This chapter looks in detail at the methods used by these studies to provide an exhaustive overview and description of these discrepancies. During the reviewing of the 175 papers composing the corpus of this study, it quickly appeared that several papers do not provide full and complete information on their sampling and analytical approaches. In addition, even if some practices are more generalized than others, several differences made it impossible to find more than two papers analyzing river water with fully comparable methods. A complete description as well as key challenges is provided in this chapter regarding the definition of microplastics, their sampling methods, sample preparation, identification, and quantification approaches.