Sample Collection, Preparation and Analytical Considerations for Environmental Microplastics Studies: The Path Forward Using New ASTM Standards for Microplastics

Analyzing Microplastics in the Environment: Striving to Better Assess Occurrence, Fate and Effects
Oral Presentation

Prepared by H. Allen1, A. Cook2, W. Robberson3
1 - USEPA Region 9, 619 Mound, South Pasadena, CA, 91030, United States
2 - Ocean P3 Systems, 67 Prospect Rd, Piedmont, California, 94610, United States
3 - Ocean P3 Systems, 1230 Clay Street, APT 203, San Francisco, CA, 94108, United States


Contact Information: allen.harryl@epa.gov; 415 218-7406

ABSTRACT

Demand for microplastic pollution monitoring is expected in increase across media, institutions and industrial sectors. Microplastics occur as a heterogenous mixture comprised of particulates and fibers of various polymeric materials with variable sizes and densities and are very difficult to analyze. Count-based identification methods using spectroscopy require rigorous preparation techniques to separate polymers from other organic and inorganic materials in environmental samples, such as water with high levels of suspended solids. Mass-based methods, most notably Pyrolysis-GC/MS, enable users to achieve polymer identification and mass quantitation directly from samples with minimal particle separation. The resulting robust and repeatable mass/mass or mass/volume measurements from Py-GCMS are applicable to samples from multiple environmental media including water, soils, sediments, and air. In addition, gravimetric analysis provides strong comparability to estimation of other types of pollutants. Mass-based measurements are useful for applications such as mean or median pollutant estimation, trend analysis, univariate and multivariate inferential statistics, and regression modeling. The selection of the appropriate analytical method and data analysis must be suited to the Study Goals and Conceptual Model. This talk will present insights into the development of appropriate microplastic sample planning with emphasis on recent efforts in development of ASTM standards for sample collection, preparation and analysis as well as prospective data interpretation.