Microplastic distribution characteristics and storage in a multi-species saltmarsh

Plastic has greatly changed modern society, and it has become an indispensable material in our daily lives. Microplastics are now regarded as the serious environmental threats due to the management limitations. Saltmarshes are one of the most productive ecosystems on earth and a high-efficiency blue carbon sink. As an emerging contaminant, the load, transport and fate of microplastics are largely neglected in saltmarshes. Here, we firstly measured the mass concentration of microplastics in the sediment cores of a multi-species saltmarsh by pressurized liquid extraction and modified double-shot pyrolysis gas chromatography-mass spectrometry. The major microplastics in saltmarsh sediments were polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP). The microplastic mass concentration in the sediment of Scirpus mariqueter was greater than Phragmites australis and mudflat. As artificial carbon, carbon content of microplastics accounts for 1.15% of total organic carbon. Overall, the results suggest that saltmarsh vegetation can efficiently drive the microplastic settling and retention. Therefore, the microplastic distribution characteristics in saltmarsh can be effected by the vegetation types and their distribution pattern.