Effective management of urban solid waste in the Metropolitan Region of Belém, State of Pará, Brazil is essential for conserving ecosystems and public health in eight cities, emphasizing the municipality of Marituba. Considering the vulnerability of underground water resources in Marituba to pollution due to the possible impact of leachate percolation from the landfill, this study evaluates the quality of groundwater captured in tubular wells from different adjacent locations potentially used for human consumption. For this purpose, the systematic methodologies of the groundwater quality index and human health risk assessment analysis: non-carcinogenic and carcinogenic risk to human health were used based on chronic daily intake of heavy metals by consumption and dermal adsorption of groundwater, measured through risk quotients, risk index, and incremental lifetime cancer risk. To evaluate the interrelationships of pollutants, analysis of variance, hierarchical cluster analysis, and principal component analysis were used based on the spatio-temporal quantification of pH, temperature, electrical conductivity, As, Al, Ba, Co, Cd, Cu, Cr, Fe, Hg, Ni, Pb, Sb, Se, U, and Zn. Residents of the study area are not at potential risk, as the results demonstrate that groundwater is within the potability standards of Brazilian legislation, except for aluminum concentrations, which ranged from 53.12 to 378.01 μg L⁻¹ and 3.82 to 339.5 μg L⁻¹ in the dry and rainy seasons, respectively, exceeding the established limit of 200.0 μg L⁻¹. The quality index for groundwater and the heavy metal pollution index demonstrated that groundwater has good drinking quality with low metal contamination. The risk was considered low at all sampling sites in the non-carcinogenic risk assessment. Principal component analysis indicated that the sources of metal pollution are natural origins and anthropogeny. In this sense, they become worried because aluminum is a recognized neurotoxicant that can interfere with the central nervous system’s critical physiological and biochemical processes. Furthermore, despite complying with potability standards, trace concentrations of highly toxic metals such as As, Pb, Cd, and Ni may indicate initial contamination by landfill leachate.

Objective: This study aimed to assess the feasibility of using rainwater for human consumption as an alternative water supply in the Eastern Amazon, through a social technology for collection and treatment. Theoretical Framework: Despite the region's water abundance, access to potable water is limited, especially in isolated communities. Rainwater harvesting emerges as a viable alternative, provided its quality is rigorously evaluated. Method: The research was conducted in seven households on Ilha das Onças (Barcarena-PA) and one control unit in Belém. Water samples collected from rooftops and stored in cisterns were analyzed before and after treatment with sodium hypochlorite and filtration using activated carbon and polypropylene candles. Physical-chemical parameters (pH and electrical conductivity) were evaluated and compared with commercial brands, while microbiological parameters (coliforms) and trace metals were also analyzed. Results and Discussion: Rainwater had an average pH of 5.16 and conductivity of 9.1 μS·cm⁻¹; after treatment, these values slightly increased but remained below those found in commercial waters. Treatment reduced the microbiological load, although 53.8% of samples still showed total coliforms and 20.5% E. coli. In general, the samples did not show metal concentrations above the levels established by legislation. Research Implications: The results suggest that, with proper operation and maintenance, rainwater harvesting and treatment systems are a viable solution for water supply in Amazonian communities. Originality/Value: The study highlights a low-cost, sustainable alternative adapted to the region’s socio-environmental context for promoting health and well-being.