Spatial distribution of microplastics in the superficial sediment of a mangrove in Southeast Brazil: A comparison between fringe and basin

Abstract

The presence of microplastics (MPs) has been observed globally in every marine environment, including mangroves. However, the distribution of MPs in mangroves comparing fringe and basin forests and their ecological consequences need be better investigated. The objectives of this study were to verify the presence, distribution and types of MPs in a mangrove area in southeast Brazil. Further, we linked the presence of vegetation and urban activities with MPs presence at these sites. Eight mangrove sites in Vitória Bay were delimited and classified as fringe or basin, totaling 16 sample points. Superficial sediments were collected, then MPs classified and quantified by shapes and colors. A total of 2175 MPs were observed in the mangrove basin and fringe of sites analyzed (66.4% and 33.6%, respectively), suggesting high levels of MPs in basin sites. The color proportion of MPs found was blue (54%), transparent (21%), black (10%), red and green (6% each) and yellow and white (<1% each). Filaments accounted for 88.7% of the total, compared with 11.3% from fragments. The majority of MPs were found at the basin sites with less preserved vegetation. A positive correlation was found between the total number of MPs and the density of dead vegetation, indicating that degraded environments are more susceptible to MP accumulation. Thus, our data suggest that MPs are widely distributed and associated with lower hydrodynamism (basin region), less preserved vegetation and urban activities.