Resumo A contaminação de águas superficiais por elementos metálicos é uma preocupação ambiental em cidades com parques industriais, em Manaus - AM, Brasil. As preocupações estão relacionadas à bioacumulação desses elementos e sua toxicidade, que podem afetar a ecologia dos ambientes aquáticos e a saúde humana. O estudo avaliou o papel da sazonalidade nas concentrações de metais potencialmente tóxicos na bacia do São Raimundo, na cidade de Manaus. As amostras foram coletadas em junho de 2021, outubro de 2021 e janeiro de 2022 em trinta e um pontos de coleta. Os parâmetros físico-químicos foram analisados de acordo com os Methods for the Examination of Water and Wastewater of the APHA/AWWA. Os metais foram analisados por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP-OES), e os dados por análise de variância (ANOVA), correlação de Pearson e Análise de Componentes Principais (PCA). Al apresentou valores fora do estabelecido pela legislação brasileira, com média de 267.2 ug/L. A ANOVA mostrou um forte papel da sazonalidade nas concentrações dos metais, com os períodos de inundação na bacia apresentando as menores concentrações de metais. Como Bário (Ba) e Berílio (Be) com médias próximas de 0.0 ug/L no período de cheia, e período de seca com valores de 0.50 ug/L. A correlação mostrou a relação de Ba, Be e Titânio (Ti) com DBO. A PCA indicou os metais Ba, Be e Ti como os contaminantes mais relevantes na bacia. Foi possível desenvolver um mapa para identificar os pontos de amostragem onde as concentrações desses metais são maiores.

Abstract Contamination of surface water by metallic elements is an environmental concern in cities with industrial parks such as Manaus in Amazonas, Brazil. The concerns are related to the bioaccumulation of these elements and their toxicity, which affect the ecology of aquatic environments and human health. The study evaluated the role of seasonality in the concentrations of potentially toxic metals in the São Raimundo Basin in Manaus. Collections were carried out in June 2021, October 2021 and January 2022 at thirty collection points. The physicochemical parameters were analyzed according to the Methods for the Examination of Water and Wastewater of the APHA/AWWA. The metals were analyzed using optical emission spectrometry with inductively coupled plasma (ICP-OES), and the data using analysis of variance (ANOVA), Pearson correlation and Principal Component Analysis (PCA). All presented values outside those established by Brazilian legislation, with an average of 267.2 ug/L. ANOVA showed role of seasonality in the concentrations of the metals, with the periods of flooding in the basin having the lowest concentrations of metals. Such as Barium (Ba) and Beryllium (Be) with averages close to 0.0 ug/L in the flood period, and dry period with average values of 0.50 ug/L. The correlation showed the relationship of Ba, Be and Titanium (Ti) with the Biochemical Oxygen Demand (BOD). PCA indicated the metals Ba, Be and Ti as the most relevant contaminants in the basin. It was possible to develop a map to identify the sampling points where the concentrations of these metals are the highest.

Beneficial interactions between plants and microorganisms have been investigated under different ecological, physiological, biochemical, and genetic aspects. However, the systematic exploration of biomolecules with potential for biotechnological products from this interaction still is relatively scarce. Therefore, this study aimed the evaluation of the diversity and antimicrobial activity of the endophytic fungi obtained from roots, stems and leafs of Myrcia guianensis (Myrtaceae) from the Brazilian Amazon. 156 endophytic fungi were isolated and above 80% were identified by morphological examination as belonging to the genera Pestalotiopsis, Phomopsis, Aspergillus, Xylaria, Nectria, Penicillium and Fusarium. Fermented broth of those fungi were assayed for antimicrobial activity and four inhibited the growth of Staphylococcus aureus, Enterococcus faecalis, Candida albicans and Penicillium avellaneum. As the strain named MgRe2.2.3B (Nectria haematococca) had shown the most promising results against those pathogenic strains, its fermented broth was fractioned and only its two low polar fractions demonstrated to be active. Both fractions exhibited a minimum bactericidal concentration of 50 µg.mL-1 against S. aureus and a minimum fungicidal concentration of 100 µg.mL-1 against P. avellaneum. These results demonstrate the diversity of fungal genera in M. guianensis and the potential of these endophytic fungi for the production of new antibiotics.