Variação espacial de cátions, ânions e variáveis físico-químicas no rio Solimões-Amazonas entre Manaus e Jutaí, bacia amazônica

Abstract

RESUMOCátions e ânions majoritários são espécies químicas de grande importância nos diversos compartimentos aquáticos, porém, pouco abordados de forma exclusiva na bacia amazônica. Neste sentido, o objetivo deste estudo foi avaliar a dinâmica espacial de Na Spatial variation of cations, anions and physicochemical variables in the Solimões-Amazonas River, between Manaus and Jutaí, Amazon Basin ABSTRACTMajor cations and anions are chemical species with great importance in different water compartments. However, no specific attention has been given to them in the Amazon basin. This study aimed to assess the spatial dynamic of Na + , Ca 2+ , K + , Mg 2+ , Cl -and SO 4 2-in a specific section of the Solimões-Amazonas river taking into account the alkalinity, hydrogen potential (pH), conductivity electric (EC), total suspended solids (TSS) and total organic carbon (TOC). Samples were collected in May, July and September 2012 in seven points in the Solimões-Amazonas River and in the mouth of some of its main tributaries: rivers Jutaí, Juruá, Japurá and Purus. Cations and anions were analyzed by ion chromatography, TSS by gravimetry, pH by potentiometry, alkalinity by potentiometric titration, EC by conductimetry and TOC by catalytic oxidation combustion. The average cation concentrations followed this order: Ca 2+ > Na + > Mg 2+ > K + and anion SO 4 2-> Cl. From the upstream of the river towards its downstream section there was a tendency for a decrease in cations and anions accumulation, pH, EC, TSS and alkalinity. On the other hand, there was an increase in TOC. The present study showed changes in chemical characteristics of Solimões River along its course. It was observed the contribution of the tributary rivers as one of the responsible factors for these changes.

Avaliação da qualidade ambiental dos recursos hídricos ao longo do rio Preto da Eva no Amazonas, Brasil

“…Durante a enchente, os valores foram entre 125 e 160 mg/L, onde ambos os períodos e pontos de coleta permaneceram abaixo de 400 mg/L estipulado pela resolução ambiental (Brasil, 2005). A quantidade e a qualidade dos sólidos totais no ambiente aquático são determinadas por ações naturais do meio, dentre elas os processos erosivos de formação de rios de água branca (Ex: Solimões, Madeira) (Souto et al, 2015), e por ações antrópicas que acabam incorporando no ambiente aquático níveis elevados de matéria orgânica, nutrientes e sedimentos por meio de esgoto não tratado .…”