Hidroquímica e Qualidade das águas superficiais na porção Sul do município de Presidente Figueiredo, Borda Norte da Bacia do Amazonas

Abstract

Anthropogenic activities have been causing numerous damages to ecosystems. Industries, agriculture, landfills, mining, and the production of chemical and biological waste in aquatic environments are studied to identify the impact and how it affects the environment and human health. To identify the geochemistry of surface waters, it was necessary to analyze how lakes are affected by human activities and natural processes. The hydrochemical characteristics can be used to evaluate the relationship between rock weathering and artificial sources. The blue lagoons and waterfalls in the study region were used as research subjects to explore the physicochemical and bacteriological characteristics and assess the quality of these waters within the bathing standards, according to the legislation of CONAMA 357/2005 and 274/2000.The sampling and analysis procedures followed the manual ISSN 1980-3958/2011 (PARRONet al., 2011) and APHA (2017). The samplings were conducted respecting the hydrological cycle of the municipality of Presidente Figueiredo-AM, divided into four campaigns between 2021 and 2023. The analyses performed included: E. coli, pH, conductivity, dissolved oxygen,turbidity, TSS, alkalinity, cations (Na+, K+, Ca2+, Mg2+ e NH4 +), anions (Cl-, NO3-, SO42- e PO43), and potentially toxic metals (Fe, Al, Mn, Zn, Ba, Ag, Pb, Cd, Cr, Ni, and Cu). The results indicated that the analyzed waters follow the CONAMA 357 and 274 regulations for bathing. The measurements align with the standards established by CONAMA 357/2005 and 274/2000, which regulate the quality of surface water for primary contact recreational use. Among the sampling points, Lagoa LG exhibited less anthropogenic influence, with pH and EC values consistent with regional characteristics. Na and K were the main constituents of the dissolved phase, preserving natural characteristics. Conversely, Cachoeira CL showed a higher presence of ions, CF, and pH close to neutrality, indicating greater human impact. The metals Fe, Al, Mn, Zn, and Ba showed low concentrations, reflecting the weathering conditions of humid tropical regions. However, the continuity of studies and constant monitoring of aquatic ecosystems are essential to ensure the maintenance of this compliance over time.