Densidade de bactérias associadas a macroplásticos de sedimentos de fundo

Abstract

The pollution of water bodies by microplastics represents a global challenge, because among the risks to the microbiota and the environment, these are presented as an ideal medium for the growth of microorganisms, enabling the spread of pathogens and the invasion of environments by invasive species that can affect the aquatic ecosystem and the health of the population. With this in mind, the objective of this study was to investigate the seasonal density of heterotrophic bacteria and Pseudomonas aeruginosa adsorbed on macroplastic samples and bottom sediments in the Barbado stream microbasin in Cuiabá-MT, the characterization of sampling points, qualitative analysis of the parameters physical and chemical properties of water and quantification of microplastics in bottom sediments. The collections were carried out at four sampling points of the watershed during the rainy season (December/2019 to February/2020) and dry season (June/2020 to August/2020). This study showed that the density of heterotrophic bacteria in macroplastic and bottom sediments showed no significant difference between the sampling points, except for sediment samples in the seasonal period and when comparing the macroplastic and bottom sediment groups with each other. On the other hand, there was no growth of Pseudomonas aeruginosa in macroplastic, only in bottom sediments, with a difference in density between the points and the rainy and dry periods. The characterization of the collection points in the study area showed the presence of household waste, especially of the macroplastic type, as well as the release of domestic effluent without prior treatment, eutrophication and bad odor. In view of the qualitative analysis of the physical and chemical parameters of the water, the degradation of the water course was verified, since the dissolved oxygen presented values below the minimum established by CONAMA 357/2005, as well as the high electrical conductivity observed. As for microplastic analysis in bottom sediments in the stream under study, it did not differ significantly between sampling points and campaigns. However, a total of 103 units/kg of microplastic were quantified in the rainy season and 65 units/kg in the dry season, being mostly of the fiber, films and fragments type, respectively.