1.1 ,This practice provides for the sample preparation of collected water samples with high, medium, or low suspended solids to determine the presence, count, polymer type, and physical characteristics of microplastic particles and fibers. It has been designed for the preparation of samples collected from drinking water, surface waters, wastewater influent and effluent (secondary and tertiary), and marine waters using collection practice (Practice D8332). This practice is not limited to these particular water matrices, however, the applicability of this practice to other aqueous matrices must be demonstrated.