Distribution and retention of microplastics in plantation mangrove forest sediments

Microplastics (MPs) in ocean tides can be effectively intercepted by mangroves, especially sediments, which are considered to be effective sinks. However, the retention of plantation mangrove forests on MPs is still unclear. In this study, the spatial distribution and its implication factors of MPs in surface sediments of plantation mangrove forests were investigated for the first time. In plantation forests, MPs were detected with abundances ranging from 67 & PLUSMN; 21 to 203 & PLUSMN; 25 items/kg, and plantation forests were significantly lower than natural forests at the CJ sampling site (p < 0.05). Plantation forests had fewer fibrous MPs than natural forests (p < 0.05). Furthermore, the MPs abundance showed strong linear relationships with the sand content (p = 0.002, R2 = 0.86) and Aegi-ceras corniculata biomass (p = 0.001, R2 = 0.84). Partial least squares path modeling analysis (PLS-PM) indicated that these two factors influenced MPs abundance by retaining MPs with fibrous, fragmented, denser and larger -sized characteristics. Our results revealed the differences in MPs abundance and characteristics between plan-tation and natural mangrove forests, and it is necessary to monitor MPs pollution to provide significant guidance for the restoration of constructed wetlands.

Automated summary

This study investigated the spatial distribution and factors influencing microplastics (MPs) in surface sediments of plantation mangrove forests for the first time. The results showed that plantation forests had lower abundance of MPs, especially fibrous MPs, compared to natural forests. The abundance of MPs was strongly related to sand content and Aegi-ceras corniculata biomass.