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Detecting microplastics in marine sediments: A methods comparison of isolation & extraction procedures
Citation:
Cashman, M., K. Ho, T. Langknecht, S. Robinson, AND R. Burgess. Detecting microplastics in marine sediments: A methods comparison of isolation & extraction procedures. EPA Region 1 Meeting, Boston, Massachusettes, July 10, 2019.
Impact/Purpose:
Microplastics (MPs) are a growing concern in our environment. Methods to extract MPs from environmental matrices (sediment, water & tissues) are necessary to understand the effects of these persistent, ubiquitous particles. Methods are not yet standardized in this young and rapidly growing field of study. This presentation is an overview of the AED's progress on 1) evaluating methods to extract various MPs from sediments; 2) developing a hybrid method to extract MPs from sediments; and 3) using the hybrid method to extract MPs from environmental sediments across the United States.
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. This presentation highlights research progress with the RARE Project, :Assessment of current methods for the extraction and isolation of microplastics from sediment and conduct of a multi-regional survey of microplastics in estuarine and marine sediments". 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 results from the isolation of MPs from environmental sediments collected by Regions 1,3, and 9.