Habitat Integrity and Microplastic Contamination in Amazonian Streams: Assessment of Water, Sediment, and Fish and Identification of Predominant Polymers

Microplastic (MP) contamination is a global problem that affects several ecosystems. This contamination is present in streams in the Amazon region, which is subject to great risks through anthropogenic actions. The present study verified the possible relationship between the physical integrity of the habitat and the levels of MP contamination in Amazonian streams, evaluating which environmental component, among water, sediment and biodiversity (fish) was most contaminated by MPs and which type of polymer was most present. No relationship was found between the integrity of the environment and the concentration of MPs in streams. The concentration of MPs in the sediments was higher than that found in the water, and only eight fish specimens were contaminated. Despite the low concentration rates of MPs recorded, our results suggest that streams can function as a deposit of MPs. It is possible that the lower level of contamination is associated with the low presence of point sources of MPs, as well as some physical factors that can transport MPs to other systems. The low concentration of MPs in streams may explain lower ingestion rates by fish, since low concentrations of particles in the environment reduce the chances of ingestion of these particles by organisms.