Ocorrência de microplásticos na dieta de peixes em um gradiente de uso antrópico do rio Amapari (Serra do Navio, Amapá, Brasil)

Abstract

Microplastics are already considered major water pollutants. Recent studies have highlighted the role of the atmosphere in transporting microplastics to remote areas, and we can emphasize the influence of human activities on the increase of this pollutant in the environment. Global research shows that microplastics harm aquatic organisms, affecting their populations and ecosystems. This work aims to understand whether the consumption of microplastics by fish increases according to the level of anthropic occupation along a section of the Amapari River, located in the northern Brazilian Amazon. Field collections were carried out in February and June 2024 at three points along the Amapari River: upstream, in a protected area where there are no residences and potential sources of microplastic dispersion within the boundaries of the Tumucumaque Mountains National Park, which has rules for employees and visitors regarding the use and preservation of the environment; at a point downstream from the park, in the locality of Sete Ilhas, with reduced use of the river; and in Serra do Navio, a town with 4,673 inhabitants that intensively uses the river for transportation, food, recreation, etc. The fish were collected using gillnets and hooks, and weighed, measured, and dissected in the field to remove their gills, stomachs, and intestines, which were fixed in 10% formalin for laboratory analysis. In the laboratory, the samples underwent chemical digestion with KOH, and the resulting solution was analyzed under a stereomicroscope. The color, size, shape, and type of synthetic material were recorded and tabulated for subsequent statistical analysis, in order to understand whether the quantity of microplastics follows a positive pattern in relation to the anthropic occupation of the three collection areas. After analysis, the presence of microplastics was confirmed at all three collection points, regardless of the area's anthropic occupation. Fish from both the metropolitan region of Serra do Navio and the National Park are equally contaminated by microplastics, indicating that the use of this variable is not suitable for environmental impact studies and that the dispersion of microplastics occurs through natural means as well as anthropic ones, with atmospheric transport being the primary means.