Microplastic Deposition and its Response to Extreme Flood Events: A Case
Study of Yangtze Estuary, China
Abstract
Microplastics are ubiquitously found in the environment; however, our
knowledge about their storage and mechanism in the burial record is
scarce. We selected a core (CCYY1) in the tidal flat of the Yangtze
Estuary and investigated its microplastic pollution and sediment grain
size. Both plastic production and sediment grain size were significantly
positively correlated with microplastic abundance, revealing that the
distribution of microplastics in the core was mutually affected by
plastic production and extreme flood events. Moreover, the sedimentary
record increased rapidly in microplastic abundance and microplastic
diversity during the historic extreme flood. The resuspension of
upstream microplastics and erosion of land-based microplastics by heavy
rain may be responsible for the increase during flood events.
Microplastic abundance had a significant period of 8 a and 22 a,
indicating the influence of El Niño-Southern Oscillation and solar
activity. This study also proposed microplastics as a proxy index for
palaeo-flooding.