Spatial and Seasonal Variations in Water Quality of the Amazon River in Parintins-AM: Influence of the Flood Pulse and Anthropogenic Pressures

Objective: This study aimed to characterize and analyze the spatial and seasonal variations in water quality in the urban stretch of the Amazon River in Parintins-AM, with the purpose of supporting water management strategies and public health protection. Theoretical Framework: The study is grounded in concepts of sustainable water resource management and the dynamics of large tropical rivers, emphasizing the role of the flood pulse, diffuse pollution, and the impacts of inadequate sanitation (Drake et al., 2021; Ferreira et al., 2021) Method: A total of 91 water samples were collected at seven points with varying degrees of anthropogenic influence between December 2023 and April 2024, covering flood and low-water periods. Physicochemical and microbiological parameters were analyzed. Descriptive statistics, ANOVA, non-parametric tests, and comparison with the CONAMA Resolution No. 357/2005 were applied using the PAST software. Results and Discussion: The results indicated thermal and chemical stability but revealed high concentrations of turbidity, total phosphorus, and Escherichia coli at certain points. Seasonal variation highlighted higher pollutant concentrations during the low-water period, demonstrating the hydrological cycle’s effect on water quality. Research Implications: The findings underscore the need for multiscale monitoring, improved basic sanitation policies, and integrated management to mitigate impacts on the Amazon basin, thereby protecting vulnerable riverside communities. Originality/Value: This study contributes by addressing gaps in water quality knowledge in urban Amazonian areas, integrating physicochemical and microbiological data with robust statistical analyses to support local environmental management decisions.