High levels of anthropogenic litter trapped in a mangrove area under the influence of different uses

The contamination of mangroves by anthropogenic litter has increased in recent decades. Notably, Brazil occupies a prominent status within Latin America, boasting the second-largest mangrove areas globally. In Santos-São Vicente Estuarine System (SESS), mangroves coexist with a preeminent port complex and substantial urbanization rates. Nevertheless, the anthropogenic litter occurrence and distribution in this ecosystem remains unknown. This study aimed to comprehensively assess anthropogenic litter across 13 strategically positioned sites in the SESS. The total litter density (Mean ± SD) was 22.84 ± 36.47 (0.00–142.00) items·m−2, putting the SESS among the top four most contaminated mangrove ecosystems worldwide. Residential zones accumulated more litter than uninhabited areas and significant correlation was seen with human modification index. Plastic was the prevalent material (70.4 %), measuring mostly between 2.5 and 30 cm (41.1 %). It is imperative that local authorities adopt comprehensive strategies to mitigate contamination, while also curtailing the litter inputs to the SSES mangrove ecosystem. •Anthropogenic litter levels in mangroves increased in recent decades.•Contamination by anthropogenic litter in Brazilian mangroves remains unknown.•The levels of anthropogenic litter were among the highest reported in mangroves.•Human modification levels were related to litter densities.•It is imperative to adopt comprehensive strategies to mitigate local contamination.