Influence of seasonality on the physical-chemical properties of water for human consumption by residents of floating villages in the interior of the Amazon

Abstract

The aim of this study was to evaluate the physicochemical properties of the water consumed by residents of floating houses and the influence of the hydrological cycles of flood and drought on these parameters. The sample consisted of 44 floating domestic units per hydrological cycle, located on the edges of the cities of Codajás, Coari and Tefé. Sociodemographic data and data related to water consumption and storage habits were collected using a semi-structured questionnaire. Water samples were collected and analyzed in accordance with the Standard Methods for the Examination of Water and Wastewater. Data were analyzed in the dry and flood hydrological phases and compared to the maximum values allowed by Ordinance GM/MS No. 888/2021. The results showed that the nitrite, manganese and free residual chlorine parameters were not in accordance with the legislation. Manganese (p = .035) and aluminum (p < .001) showed significant differences between the hydrological phases. The considerable increase in aluminum content during the flood period, even though it was within the limits of the ordinance, was also highlighted. Accordingly, even with periodic control by the supply companies, it is important to monitor the water at the point of consumption of the population. HIGHLIGHTS The water source was predominantly Amazonian tube wells.; Most residents do not pre-treat water before consumption.; High concentrations of nitrite and manganese were identified in the drinking water.; The contamination by Mn and Al showed a significant difference between the hydrological phases.; Residents of floating houses do not have good drinking water consumption and storage practices.;

Keywords

• amazonian ecosystem
• drinking water
• floating houses
• manganese
• nitrites
• public health