Microplásticos em sedimentos da foz do rio Amazonas
Data
2023-11-27
Autores
Silva, Lucas Pereira Mendes da 
Orientadores
Semensatto Junior, Décio Luis
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Microplásticos (MPs) são poluentes emergentes encontrados em todos os tipos de compartimentos
ambientais, cuja presença em ambientes aquáticos continentais tem sido reportada em maior
quantidade apenas nos últimos dez anos. No Brasil há poucos estudos publicados sobre MPs nesses
ambientes, com especial destaque para a lacuna em amostras de água e sedimento na região da foz
do Rio Amazonas. Estudo anterior realizado na Corrente Equatorial Norte apontou que a maior
concentração de alguns aditivos plásticos está justamente na região da pluma do Amazonas no
Atlântico Norte. Portanto, o objetivo deste trabalho foi detectar e quantificar a presença de MPs
em amostras de sedimentos da foz do Rio Amazonas (Macapá/AP). Para tanto, foram analisadas
dez amostras de sedimento de fundo (sete no Canal Norte e três no Canal Sul) coletadas em
Outubro/2021. No desenvolvimento deste trabalho, os MPs foram caracterizados de acordo com
suas propriedades morfométricas e químicas (composição polimérica). O processamento e análise
de amostras foram realizados de acordo com os métodos recomendados na literatura e protocolos
de controle de qualidade. Os resultados mostraram que a quantidade de MPs nos sedimentos da
foz do Rio Amazonas variou nas amostras de 99 ± 28 a 894 ± 147 partículas/100 g de sedimento
seco, bastante diferentes entre si do ponto de vista de suas dimensões morfológicas e de
composição química. Considerando em conjunto as amostras de cada canal, os volumes médios
de MPs nos canais Norte e Sul são, respectivamente, 0,159 ± 0,082 e 0,229 ± 0,190 mm3
/ 100 g
de sedimento seco. As médias das áreas superficiais específicas são 33,8 19,8 e 50,4 23,3 mm2
/ 100 g sedimento seco no Canal Norte e Canal Sul, respectivamente. Cerca de 84% dos MPs são
menores que 2 mm, sendo que foram identificadas como PET (polietileno tereftalato ou poliéster),
PAN (poliacrilonitrila) e PVAc (polivinil acetato etileno), além de celulose com pigmentos têxteis.
Globalmente, conclui-se que os níveis de poluição dos sedimentos por MPs não são
significativamente diferentes entre o Canal Sul e o Canal Norte e estão próximos aos observados
nos arredores de Manaus (AM). Esses resultados ajudam a compreender a distribuição desse
poluente na região de estudo e suas potenciais interações com os ambientes no entorno.
Microplastics (MPs) are emerging pollutants found in all types of environmental compartments, whose presence in continental aquatic environments has been reported in greater quantities only in the last ten years. In Brazil, there are few published studies on MPs in these environments, with special emphasis on the gap in water and sediment samples in the region around the mouth of the Amazon River. A previous study carried out in the North Equatorial Current showed that the highest concentration of some plastic additives is precisely in the region of the Amazon plume in the North Atlantic. Therefore, the objective of this work was to detect and quantify the presence of MPs in sediment samples from the mouth of the Amazon River (Macapá/AP). To this end, ten bottom sediment samples were analyzed (seven in the North Channel and three in the South Channel) collected in October/2021. In the development of this work, MPs were characterized according to their morphometric and chemical properties (polymeric composition). Sample processing and analysis were performed according to methods recommended in the literature and quality control protocols. The results showed that the quantity of MPs (microplastics) in the sediments at the mouth of the Amazon River varied in samples from 99 ± 28 to 894 ± 147 particles/100 g of dry sediment, significantly different from each other in terms of their morphological dimensions and chemical composition. Considering the samples from each channel together, the average volumes of MPs in the North and South channels are, respectively, 0.159 ± 0.082 and 0.229 ± 0.190 mm3 / 100 g of dry sediment. The averages of specific surface areas are 33.8 ± 19.8 and 50.4 ± 23.3 mm2 / 100 g dry sediment in the North and South channels, respectively. About 84% of the MPs are smaller than 2 mm, identified as PET (polyethylene terephthalate or polyester), PAN (polyacrylonitrile), and PVAc (polyvinyl acetate ethylene), in addition to cellulose with textile pigments. Overall, it is concluded that the levels of sediment pollution by MPs are not significantly different between the South Channel and the North Channel and are close to those observed around Manaus. These results help to understand the distribution of this pollutant in the study region and its potential interactions with the surrounding environments.
Microplastics (MPs) are emerging pollutants found in all types of environmental compartments, whose presence in continental aquatic environments has been reported in greater quantities only in the last ten years. In Brazil, there are few published studies on MPs in these environments, with special emphasis on the gap in water and sediment samples in the region around the mouth of the Amazon River. A previous study carried out in the North Equatorial Current showed that the highest concentration of some plastic additives is precisely in the region of the Amazon plume in the North Atlantic. Therefore, the objective of this work was to detect and quantify the presence of MPs in sediment samples from the mouth of the Amazon River (Macapá/AP). To this end, ten bottom sediment samples were analyzed (seven in the North Channel and three in the South Channel) collected in October/2021. In the development of this work, MPs were characterized according to their morphometric and chemical properties (polymeric composition). Sample processing and analysis were performed according to methods recommended in the literature and quality control protocols. The results showed that the quantity of MPs (microplastics) in the sediments at the mouth of the Amazon River varied in samples from 99 ± 28 to 894 ± 147 particles/100 g of dry sediment, significantly different from each other in terms of their morphological dimensions and chemical composition. Considering the samples from each channel together, the average volumes of MPs in the North and South channels are, respectively, 0.159 ± 0.082 and 0.229 ± 0.190 mm3 / 100 g of dry sediment. The averages of specific surface areas are 33.8 ± 19.8 and 50.4 ± 23.3 mm2 / 100 g dry sediment in the North and South channels, respectively. About 84% of the MPs are smaller than 2 mm, identified as PET (polyethylene terephthalate or polyester), PAN (polyacrylonitrile), and PVAc (polyvinyl acetate ethylene), in addition to cellulose with textile pigments. Overall, it is concluded that the levels of sediment pollution by MPs are not significantly different between the South Channel and the North Channel and are close to those observed around Manaus. These results help to understand the distribution of this pollutant in the study region and its potential interactions with the surrounding environments.