Qualidade Química da Água do Rio Buriti do Município de São Bernardo – Maranhão, Brasil

Resumo

Water quality is essential for human health, environmental balance, and socioeconomic development of populations. In the city of São Bernardo, Maranhão, the lack of basic sanitation, the discharge of untreated domestic sewage, and human intervention create a risk scenario for the Buriti river. In this context, this study aimed to evaluate the chemical quality of the water of the Buriti river. Four sampling areas were defined, and collections were carried out during two distinct periods (rainy and dry seasons). Nitrate levels ranged from 3.31 to 8.88 mg L^-1, close to the 10 mg L^-1 limit established by the Brazilian Council. Phosphate concentrations reached alarming levels (0.64‑4.79 mg L^-1), up to 30 times higher than the 0.1 mg L^-1 limit, indicating a risk of eutrophication. Iron (2.73‑3.02 mg L^-1) and aluminum (1.14‑1.42 mg L^-1) concentrations exceeded the maximum permitted values in the rainy season, compromising the quality of water intended for human consumption. During the dry season, a reduction in these metal concentrations was observed; however, nutrient concentrations remained high, demonstrating that pollution is continuous. Overall, the Buriti river shows indicators of anthropogenic contamination, reinforcing the urgency of public policies focused on sanitation, systematic monitoring and environmental education.