Microplastics in distal sediments from the mouth of the Amazon River

The distribution of microplastics (MPs) in the oceans is driven mostly by the interaction of ocean currents, inputs from the mouths of large rivers, coastal cities, and the routes of merchant shipping. Schmidt et al. (2019) reported organophosphate esters and bisphenols in waters along the Atlantic North Equatorial Current, finding the highest concentrations in the Amazon River plume (https://doi.org/10.1021/acs.est.9b01585), suggesting that this plume must be the largest source of organic plastic additives in the tropical North Atlantic region. Therefore, we report here a preliminary assessment of the presence of MPs in superficial sediments in areas of the deep shelf and the uppermost part of the continental slope in front of the Amazon River mouth ( 250 km off the coastline). The samples were collected in 2014 during an exhaustive campaign conducted by the Brazilian National Agency for Petroleum, Natural Gas, and Biofuels (ANP) and are stored at the Center for Applied Natural Sciences (UNESPetro, São Paulo State University, Brazil). The analysis followed the general recommendations for processing and quality control. The samples exhibited between 373 and 1113 MPs/100 g sed dw. The volumes of MPs varied from 0.084 to 0.224 mm³/100 g sed dw. The specific surface areas of MPs ranged from 20.2 to 51.6 mm²/100 g sed dw. Our project will further compare more samples and the MPs in sediments of the bathypelagic and neritic zones and correlate them with the results reported for the Atlantic North Equatorial Current. Also see: https://micro2024.sciencesconf.org/559723/document