Microplastics in mangrove sediments of the Pearl River Estuary, South China: Correlation with halogenated flame retardants' levels

Abstract Marine microplastic pollution of intertidal mangrove ecosystem is a matter of concern. However, the relationship between microplastic distribution and other pollutants such as halogenated flame retardants (HFRs) is unknown. In this study, forty-eight sediment samples were collected from three mangrove wetlands of the Pearl River Estuary (PRE), South China to investigate the distribution of microplastic and discuss the possible relationship between HFRs and microplastic abundance in mangrove sediments. The abundance of microplastic in mangrove sediments from the PRE ranged from 100 to 7900 items·kg−1 dry weight (dw), with an average of 851 ± 177 items·kg−1 dw, which was at a relatively higher level compared to other regions worldwide. The highest abundance of microplastic was observed in Shenzhen mangrove sediments. The abundance of microplastic was significantly and positively correlated with population density and gross domestic product of the PRE. The microplastics with size