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Method optimization of microplastic extraction from marine sediments
Citation:
Cashman, M., K. Ho, T. Boving, T. Langknecht, AND R. Burgess. Method optimization of microplastic extraction from marine sediments. Society of Environmental Toxicology and Chemistry (SETAC), Toronto, Ontario, CANADA, November 03 - 07, 2019.
Impact/Purpose:
Small fragments of plastic, known as Microplastics, are a growing concern for marine environments. Many methods to extract microplastics from marine sediments exist, but procedural differences largely influence the types (size, shape, color, density) of microplastics extracted. We developed a hybridized method for microplastic extraction from marine sediments which was tested on two sediments (silty and sandy) and five different microplastics. Known quantities of microplastics representing a variety of polymers, sizes, shapes, colors, and densities were amended into sediment samples. Using the new hybridized method, we were able to recover at least 70% of all amended microplastics in both sediment types.
Description:
The distribution and fate of microplastics (MPs) (plastic particles <1mm in size) in marine environments are largely unknown. There are over 100 peer reviewed extraction methods for the isolation of microplastics from marine sediments; however, major procedural differences prevent meaningful comparisons among methods. Prior to this study, we conducted a method comparison analysis to assess the applicability of five popular methods to recover microplastics of different polymers, sizes, and shapes from two sediment types. Results from the method comparison analysis suggested that isolation of different MPs is strongly dependent upon MP properties, isolation method, and sediment characteristics. These prior results were used to develop a new method to extract microplastics (45-1000μm) from amended environmental sediments which varied in sediment composition and percent organic carbon. Plastics tested included polypropylene (PP), low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET), and polyvinylchloride (PVC). Results indicated that this new method generally extracts over 70% of tested MPs from both sandy and silty sediments. The results presented include quantification of the performance of this hybridized method, as well as initial recommendations for routine microplastic monitoring in marine sediments.