The Amazon River: A Major Source of Organic Plastic Additives to the Tropical North Atlantic?

Abstract

The release of emerging organic contaminants is identified among the most critical hazards to the marine environment, and plastic additives have received growing attention due to their worldwide distribution and potential deleterious effects. Here, we report dissolved surface water concentrations of two important families of plastic additives (organophosphate esters (OPEs) and bisphenols) and other related organic compounds (perfluorinated chemicals) measured in the North Atlantic from Cape Verde to the West Indies. We found that OPEs were the most abundant contaminants, reaching remarkably high concentrations in open ocean waters (1200 km offshore of the American Coast, at the location of the Amazon river plume during the sampling period), with up to 1.3 μg L-1 (Σ9OPEs). A Lagrangian analysis confirmed that these high concentrations of contaminants originated from the Amazon River plume and were transported more than 3000 km by the North Brazil Current and its retroflection. We thus consider the Amazon River as a major source of organic contaminants of emerging concern to the tropical North Atlantic Ocean and suggest that medium-/long-range contaminant transport occurs, most certainly facilitated by the highly stratified conditions offered by the river plume.