Assessment of Water Quality in the Mamanguape River Estuary (PB): Seasonal Influence and Environmental Risks

Objective: This study aims to assess the water quality in the Mamanguape River estuary (PB), considering the influence of seasonality on physicochemical and microbiological parameters, in order to identify environmental risks and support conservation actions. Method: The adopted methodology was applied in nature, with a quantitative-qualitative, descriptive, and exploratory approach. The research was carried out at three points along the estuary (upper, middle, and lower), representing the salinity gradient between freshwater and brackish water, with sampling conducted during the rainy season (July 2023) and the dry season (December 2023). Physicochemical parameters were measured in situ using a multiparameter probe. Microbiological analyses, performed at the middle point, included total coliforms, thermotolerant coliforms, and Escherichia coli, in accordance with current regulations (CONAMA Resolutions No. 357/2005 and No. 274/2000, and Ordinance GM/MS No. 888/2021). Results and Discussion: The results showed that although most physicochemical parameters were within legal limits, turbidity and dissolved oxygen exhibited significant variations between seasons. Microbiological analysis indicated fecal contamination during the rainy season, with the presence of E. coli and coliforms, which were absent in the dry season. These findings demonstrate the influence of seasonality on water quality and suggest the presence of diffuse pollution sources, such as domestic sewage and agricultural activities. Research Implications: The practical implications of this research include providing technical data to support public policies on basic sanitation, water resource management, and continuous environmental monitoring in the Mamanguape River estuary. Originality/Value: This study contributes to the literature by integrating physicochemical and microbiological measurements with a focus on seasonal variation, offering an updated and detailed overview of water quality in the Mamanguape River estuary.